WorldWideScience

Sample records for blood-nerve barrier

  1. Fingolimod promotes blood-nerve barrier properties in vitro.

    Science.gov (United States)

    Nishihara, Hideaki; Maeda, Toshihiko; Sano, Yasuteru; Ueno, Maho; Okamoto, Nana; Takeshita, Yukio; Shimizu, Fumitaka; Koga, Michiaki; Kanda, Takashi

    2018-04-01

    The main effect of fingolimod is thought to be functional antagonism of lymphocytic S1P1 receptors and the prevention of lymphocyte egress from lymphoid tissues, thereby reducing lymphocyte infiltration into the nervous system. However, a growing number of reports suggest that fingolimod also has a direct effect on several cell types in the nervous system. Although we previously reported that fingolimod enhances blood-brain barrier (BBB) functions, there have been no investigations regarding the blood-nerve barrier (BNB). In this study, we examine how fingolimod affects the BNB. An immortalized human peripheral nerve microvascular endothelial cell line (HPnMEC) was used to evaluate BNB barrier properties. We examined tight junction proteins and barrier functions of HPnMECs in conditioned medium with or without fingolimod-phosphate and blood sera from patients with typical chronic inflammatory demyelinating polyneuropathy (CIDP). Incubation with fingolimod-phosphate increased levels of claudin-5 mRNA and protein as well as TEER values in HPnMECs. Conversely, typical CIDP sera decreased claudin-5 mRNA/protein levels and TEER values in HPnMECs; however, pretreatment with fingolimod-phosphate inhibited the effects of the typical CIDP sera. Fingolimod-phosphate directly modifies the BNB and enhances barrier properties. This mechanism may be a viable therapeutic target for CIDP, and fingolimod may be useful in patients with typical CIDP who have severe barrier disruption.

  2. Changes in the blood-nerve barrier after sciatic nerve cold injury: indications supporting early treatment

    Directory of Open Access Journals (Sweden)

    Hao Li

    2015-01-01

    Full Text Available Severe edema in the endoneurium can occur after non-freezing cold injury to the peripheral nerve, which suggests damage to the blood-nerve barrier. To determine the effects of cold injury on the blood-nerve barrier, the sciatic nerve on one side of Wistar rats was treated with low temperatures (3-5°C for 2 hours. The contralateral sciatic nerve was used as a control. We assessed changes in the nerves using Evans blue as a fluid tracer and morphological methods. Excess fluid was found in the endoneurium 1 day after cold injury, though the tight junctions between cells remained closed. From 3 to 5 days after the cold injury, the fluid was still present, but the tight junctions were open. Less tracer leakage was found from 3 to 5 days after the cold injury compared with 1 day after injury. The cold injury resulted in a breakdown of the blood-nerve barrier function, which caused endoneurial edema. However, during the early period, the breakdown of the blood-nerve barrier did not include the opening of tight junctions, but was due to other factors. Excessive fluid volume produced a large increase in the endoneurial fluid pressure, prevented liquid penetration into the endoneurium from the microvasculature. These results suggest that drug treatment to patients with cold injuries should be administered during the early period after injury because it may be more difficult for the drug to reach the injury site through the microcirculation after the tissue fluid pressure becomes elevated.

  3. Trauma-Induced Heterotopic Ossification Regulates the Blood-Nerve Barrier

    Directory of Open Access Journals (Sweden)

    Zbigniew Gugala

    2018-06-01

    Full Text Available De novo bone formation can occur in soft tissues as a result of traumatic injury. This process, known as heterotopic ossification (HO, has recently been linked to the peripheral nervous system. Studies suggest that HO may resemble neural crest-derived bone formation and is activated through the release of key bone matrix proteins leading to opening of the blood-nerve barrier (BNB. One of the first steps in this process is the activation of a neuro-inflammatory cascade, which results in migration of chondro-osseous progenitors, and other cells from both the endoneurial and perineurial regions of the peripheral nerves. The perineurial cells undergo brown adipogenesis, to form essential support cells, which regulate expression and activation of matrix metallopeptidase 9 (MMP9 an essential regulatory protein involved in opening the BNB. However, recent studies suggest that, in mice, a key bone matrix protein, bone morphogenetic protein 2 (BMP2 is able to immediately cross the BNB to activate signaling in specific cells within the endoneurial compartment. BMP signaling correlates with bone formation and appears critical for the induction of HO. Surprisingly, several other bone matrix proteins have also been reported to regulate the BNB, leading us to question whether these matrix proteins are important in regulating the BNB. However, this temporary regulation of the BNB does not appear to result in degeneration of the peripheral nerve, but rather may represent one of the first steps in innervation of the newly forming bone.

  4. Safety, efficacy, and molecular mechanism of claudin-1-specific peptides to enhance blood-nerve-barrier permeability.

    Science.gov (United States)

    Sauer, Reine-Solange; Krug, Susanne M; Hackel, Dagmar; Staat, Christian; Konasin, Natalia; Yang, Shaobing; Niedermirtl, Benedikt; Bosten, Judith; Günther, Ramona; Dabrowski, Sebastian; Doppler, Kathrin; Sommer, Claudia; Blasig, Ingolf E; Brack, Alexander; Rittner, Heike L

    2014-07-10

    The blood-nerve barrier consists of the perineurium and endoneurial vessels. The perineurial barrier is composed of a basal membrane and a layer of perineurial cells sealed by tight junction proteins preventing e.g. application of analgesics for selective regional pain control. One of the barrier-sealing proteins in the blood-nerve barrier is claudin-1. Therefore, the claudin-1-peptidomimetics (C1C2), derived from the first extracellular loop (ECL1) on claudin-1 was developed. In this study, we further evaluated the expression of tight junction proteins in the perineurium in Wistar rats and characterized the specificity, in vivo applicability, mechanism of action as well as the biocompatibility of C1C2. In the perineurium, claudin-19, tricellulin and ZO-1, but no claudin-2, 3, 8 and -11 were expressed. C1C2 specifically bound to the ECL1 of claudin-1 and fluorescent 5,6-carboxytetramethylrhodamine-C1C2 was rapidly internalized. Opening the perineurium with C1C2 reduced the mRNA and protein expression of claudin-1 and increased small and macromolecule permeability into the peripheral nerve. Application of C1C2 facilitated regional analgesia using μ-opioid receptor agonists like DAMGO or morphine without motor impairment in naïve rats as well as rats with hind paw inflammation. In contrast the control peptide C2C2 derived from ECL1 on claudin-2 did neither open the barrier nor facilitated opioid-mediated regional analgesia. C1C2 delivery was well tolerated and caused no morphological and functional nerve damage. C1C2 effects could be reversed by interference with the wnt-signal-transduction pathway, specifically the homeobox transcription factor cdx2, using a glycogen-synthase-kinase-3 inhibitor. In summary, we describe the composition of and a pathway to open the perineurial barrier employing a peptide to deliver hydrophilic substances to the peripheral nerve. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. αMβ2-integrin-intercellular adhesion molecule-1 interactions drive the flow-dependent trafficking of Guillain-Barré syndrome patient derived mononuclear leukocytes at the blood-nerve barrier in vitro

    Science.gov (United States)

    Yosef, Nejla; Ubogu, Eroboghene E.

    2012-01-01

    The mechanisms of hematogenous leukocyte trafficking at the human blood-nerve barrier (BNB) are largely unknown. Intercellular adhesion molecule-1 (ICAM-1) has been implicated in the pathogenesis of Guillain-Barré syndrome (GBS). We developed a cytokine-activated human in vitro BNB model using primary endoneurial endothelial cells. Endothelial treatment with 10 U/mL tissue necrosis factor-α and 20 U/mL interferon-γ resulted in de novo expression of proinflammatory chemokines CCL2, CXCL9, CXCL11 and CCL20, with increased expression of CXCL2-3, CXCL8 and CXCL10 relative to basal levels. Cytokine treatment induced/ enhanced ICAM-1, E- and P-selectin, vascular cell adhesion molecule-1 and the alternatively spliced pro-adhesive fibronectin variant, fibronectin connecting segment-1 expression in a time-dependent manner, without alterations in junctional adhesion molecule-A expression. Lymphocytes and monocytes from untreated GBS patients express ICAM-1 counterligands, αM- and αL-integrin, with differential regulation of αM-integrin expression compared to healthy controls. Under flow conditions that mimic capillary hemodynamics in vivo, there was a >3-fold increase in total GBS patient and healthy control mononuclear leukocyte adhesion/ migration at the BNB following cytokine treatment relative to the untreated state. Function neutralizing monoclonal antibodies against human αM-integrin (CD11b) and ICAM-1 reduced untreated GBS patient mononuclear leukocyte trafficking at the BNB by 59% and 64.2% respectively. Monoclonal antibodies against αL-integrin (CD11a) and human intravenous immunoglobulin reduced total leukocyte adhesion/migration by 22.8% and 17.6% respectively. This study demonstrates differential regulation of αM-integrin on circulating mononuclear cells in GBS, as well as an important role for αM-integrin-ICAM-1 interactions in pathogenic GBS patient leukocyte trafficking at the human BNB in vitro. PMID:22552879

  6. Calcium regulation in frog peripheral nerve by the blood-nerve barrier

    International Nuclear Information System (INIS)

    Wadhwani, K.C.

    1986-01-01

    The objectives of this research were: (a) to investigate the characteristics of calcium transport across the perineurium and the endoneurial capillaries, and (b) to gain a better understanding of the extent of calcium homeostasis in the endoneurial space. To study the nature of calcium transport across the perineurium, the flux of radiotracer 45 Ca was measured through the perineurial cylinder, isolated from the frog sciatic nerve, and through the perineurium into the nerve in situ. To study the nature of calcium transport across the endoneurial capillaries, the permeability-surface area product (PA) of 45 Ca was determined as a function of the calcium concentration in the blood. To study calcium homeostasis, the calcium content of the frog sciatic nerve was determined as a function of chronic changes in plasma [Ca

  7. Barrier Systems

    NARCIS (Netherlands)

    Heteren, S. van

    2015-01-01

    Barrier-system dynamics are a function of antecedent topography and substrate lithology, Relative sea-level (RSL) changes, sediment availability and type, climate, vegetation type and cover, and various aero- and hydrodynamic processes during fair-weather conditions and extreme events. Global change

  8. Information barriers

    International Nuclear Information System (INIS)

    Fuller, J.L.; Wolford, J.

    2001-01-01

    Full text: An information barrier (IB) consists of procedures and technology that prevent the release of sensitive information during a joint inspection of a sensitive nuclear item, and provides confidence that the measurement system into which it has been integrated functions exactly as designed and constructed. Work in the U.S. on radiation detection system information barriers dates back at least to 1990, even though the terminology is more recent. In January 1999 the Joint DoD-DOE Information Barrier Working Group was formed in the United States to help coordinate technical efforts related to information barrier R and D. This paper presents an overview of the efforts of this group, by its Chairs, as well as recommendations for further information barrier R and D. Progress on the demonstration of monitoring systems containing IBs is also provided. From the U.S. perspective, the basic, top-level functional requirements for the information barrier portion of an integrated radiation signature-information barrier inspection system are twofold: The host must be assured that his classified information is protected from disclosure to the inspecting party; and The inspecting party must be confident that the integrated inspection system measures, processes, and presents the radiation-signature-based measurement conclusion in an accurate and reproducible manner. It is the position of the United States that in the absence of any agreement to share classified nuclear weapons design information in the conduct of an inspection regime, the requirement to protect host country classified warhead design information is paramount and admits no tradeoff versus the confidence provided to the inspecting party in the accuracy and reproducibility of the measurements. The U.S. has reached an internal consensus on several critical design elements that define a general standard for radiation signature information barrier design. These criteria have stood the test of time under intense

  9. Floating barrier

    Energy Technology Data Exchange (ETDEWEB)

    1968-05-06

    This floating barrier consists of relatively long elements which can be connected to form a practically continuous assembly. Each element consists of an inflatable tube with an apron of certain height, made of impregnated fabric which is resistant to ocean water and also to hydrocarbons. Means for connecting one element to the following one, and means for attaching ballast to the apron are also provided.

  10. Smart parking barrier

    KAUST Repository

    Alharbi, Abdulrazaq M.

    2016-01-01

    positioning of the movable parking barrier, and a parking controller configured to initiate movement of the parking barrier, via the barrier drive. The movable parking barrier can be positioned between a first position that restricts access to the parking

  11. Magnetic resonance imaging of blood brain/nerve barrier dysfunction and leukocyte infiltration: closely related or discordant?

    Directory of Open Access Journals (Sweden)

    Gesa eWeise

    2012-12-01

    Full Text Available Unlike other organs the nervous system is secluded from the rest of the organism by the blood brain (BBB or blood nerve barrier (BNB preventing passive influx of fluids from the circulation. Similarly, leukocyte entry to the nervous system is tightly controlled. Breakdown of these barriers and cellular inflammation are hallmarks of inflammatory as well as ischemic neurological diseases and thus represent potential therapeutic targets. The spatiotemporal relationship between BBB/BNB disruption and leukocyte infiltration has been a matter of debate. We here review contrast-enhanced magnetic resonance imaging (MRI as a non-invasive tool to depict barrier dysfunction and its relation to macrophage infiltration in the central and peripheral nervous system under pathological conditions. Novel experimental contrast agents like Gadofluorine M (Gf allow more sensitive assessment of BBB dysfunction than conventional Gadolinium (Gd-DTPA-enhanced MRI. In addition, Gf facilitates visualization of functional and transient alterations of the BBB remote from lesions. Cellular contrast agents such as superparamagnetic iron oxide particles (SPIO and perfluorocarbons (PFC enable assessment of leukocyte (mainly macrophage infiltration by MR technology. Combined use of these MR contrast agents disclosed that leukocytes can enter the nervous system independent from a disturbance of the BBB, and vice versa, a dysfunctional BBB/BNB by itself is not sufficient to attract inflammatory cells from the circulation. We will illustrate these basic imaging findings in animal models of multiple sclerosis (MS, cerebral ischemia and traumatic nerve injury and review corresponding findings in patients.

  12. Sprache als Barriere (Language as a Barrier)

    Science.gov (United States)

    Mattheier, Klaus

    1974-01-01

    The concept of language barrier has its derivations in the fields of dialectology, sociology and psychology. In contemporary usage however, the concept has two meanings i.e. regional-cultural barrier and socio-cultural barrier. (Text is in German.) (DS)

  13. Smart parking barrier

    KAUST Repository

    Alharbi, Abdulrazaq M.

    2016-05-06

    Various methods and systems are provided for smart parking barriers. In one example, among others, a smart parking barrier system includes a movable parking barrier located at one end of a parking space, a barrier drive configured to control positioning of the movable parking barrier, and a parking controller configured to initiate movement of the parking barrier, via the barrier drive. The movable parking barrier can be positioned between a first position that restricts access to the parking space and a second position that allows access to the parking space. The parking controller can initiate movement of the movable parking barrier in response to a positive identification of an individual allowed to use the parking space. The parking controller can identify the individual through, e.g., a RFID tag, a mobile device (e.g., a remote control, smartphone, tablet, etc.), an access card, biometric information, or other appropriate identifier.

  14. Barrier cell sheath formation

    International Nuclear Information System (INIS)

    Kesner, J.

    1980-04-01

    The solution for electrostatic potential within a simply modeled tandem mirror thermal barrier is seen to exhibit a sheath at each edge of the cell. The formation of the sheath requires ion collisionality and the analysis assmes that the collisional trapping rate into the barrier is considerably slower than the barrier pump rate

  15. Barriers to fusion

    International Nuclear Information System (INIS)

    Berriman, A.C.; Butt, R.D.; Dasgupta, M.; Hinde, D.J.; Morton, C.R.; Newton, J.O.

    1999-01-01

    The fusion barrier is formed by the combination of the repulsive Coulomb and attractive nuclear forces. Recent research at the Australian National University has shown that when heavy nuclei collide, instead of a single fusion barrier, there is a set of fusion barriers. These arise due to intrinsic properties of the interacting nuclei such deformation, rotations and vibrations. Thus the range of barrier energies depends on the properties of both nuclei. The transfer of matter between nuclei, forming a neck, can also affect the fusion process. High precision data have been used to determine fusion barrier distributions for many nuclear reactions, leading to new insights into the fusion process

  16. Extremal surface barriers

    International Nuclear Information System (INIS)

    Engelhardt, Netta; Wall, Aron C.

    2014-01-01

    We present a generic condition for Lorentzian manifolds to have a barrier that limits the reach of boundary-anchored extremal surfaces of arbitrary dimension. We show that any surface with nonpositive extrinsic curvature is a barrier, in the sense that extremal surfaces cannot be continuously deformed past it. Furthermore, the outermost barrier surface has nonnegative extrinsic curvature. Under certain conditions, we show that the existence of trapped surfaces implies a barrier, and conversely. In the context of AdS/CFT, these barriers imply that it is impossible to reconstruct the entire bulk using extremal surfaces. We comment on the implications for the firewall controversy

  17. Safety- barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2008-01-01

    Safety-barrier diagrams and the related so-called 'bow-tie' diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation of safety-barrier diagrams to other methods such as fault...... trees and Bayesian networks is discussed. A simple method for quantification of safety-barrier diagrams is proposed. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk analysis with operational safety management....

  18. Safety-barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2007-01-01

    Safety-barrier diagrams and the related so-called "bow-tie" diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation with other methods such as fault trees and Bayesian networks...... are discussed. A simple method for quantification of safety-barrier diagrams is proposed, including situations where safety barriers depend on shared common elements. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk...... analysis with operational safety management....

  19. Multilayer moisture barrier

    Science.gov (United States)

    Pankow, Joel W; Jorgensen, Gary J; Terwilliger, Kent M; Glick, Stephen H; Isomaki, Nora; Harkonen, Kari; Turkulainen, Tommy

    2015-04-21

    A moisture barrier, device or product having a moisture barrier or a method of fabricating a moisture barrier having at least a polymer layer, and interfacial layer, and a barrier layer. The polymer layer may be fabricated from any suitable polymer including, but not limited to, fluoropolymers such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), or ethylene-tetrafluoroethylene (ETFE). The interfacial layer may be formed by atomic layer deposition (ALD). In embodiments featuring an ALD interfacial layer, the deposited interfacial substance may be, but is not limited to, Al.sub.2O.sub.3, AlSiO.sub.x, TiO.sub.2, and an Al.sub.2O.sub.3/TiO.sub.2 laminate. The barrier layer associated with the interfacial layer may be deposited by plasma enhanced chemical vapor deposition (PECVD). The barrier layer may be a SiO.sub.xN.sub.y film.

  20. Barrier penetration database

    International Nuclear Information System (INIS)

    Fainberg, A.; Bieber, A.M. Jr.

    1978-11-01

    This document is intended to supply the NRC and nuclear power plant licensees with basic data on the times required to penetrate forcibly the types of barriers commonly found in nuclear plants. These times are necessary for design and evaluation of the physical protection system required under 10CFR73.55. Each barrier listed is described in detail. Minor variations in basic barrier construction that result in the same penetration time, are also described

  1. Transport barriers in plasmas

    International Nuclear Information System (INIS)

    Caldas, I L; Szezech, J D Jr; Kroetz, T; Marcus, F A; Roberto, M; Viana, R L; Lopes, S R

    2012-01-01

    We discuss the creation of transport barriers in magnetically confined plasmas with non monotonic equilibrium radial profiles. These barriers reduce the transport in the shearless region (i.e., where the twist condition does not hold). For the chaotic motion of particles in an equilibrium electric field with a nonmonotonic radial profile, perturbed by electrostatic waves, we show that a nontwist transport barrier can be created in the plasma by modifying the electric field radial profile. We also show non twist barriers in chaotic magnetic field line transport in the plasma near to the tokamak wall with resonant modes due to electric currents in external coils.

  2. The role of the blood-brain barrier in the development and treatment of migraine and other pain disorders

    Directory of Open Access Journals (Sweden)

    Marcos Fabio DosSantos

    2014-10-01

    Full Text Available The function of the blood-brain barrier (BBB related to chronic pain has been explored by its classical role in regulating the transcellular and paracellular transport, thus controlling the flow of drugs that act at the central nervous system, such as the opioid analgesics (e.g., morphine and non-steroidal anti-inflammatory drugs (NSAIDs. Nonetheless, recent studies have raised the possibility that changes in the BBB permeability might be associated with chronic pain. For instance, changes in the relative amounts of occludin isoforms, resulting in significant increases in the BBB permeability, have been demonstrated after inflammatory hyperalgesia. Furthermore, inflammatory pain produces structural changes in the P-glycoprotein (P-gp, the major efflux transporter at the BBB. One possible explanation for these findings is the action of substances typically released at the site of peripheral injuries that could lead to changes in the brain endothelial permeability, including: substance P, calcitonin gene related peptide (CGRP and IL- 1β. Interestingly, inflammatory pain also results in microglial activation, which potentiates the BBB damage. In fact, astrocytes and microglia play a critical role in maintaining the BBB integrity and the activation of those cells is considered a key mechanism underlying chronic pain. Despite the recent advances in the understanding of BBB function in pain development as well as its interference in the efficacy of analgesic drugs, there remain unknowns regarding the molecular mechanisms involved in this process. In this review, we explore the connection between the BBB as well as the blood-spinal cord barrier (BSCB and blood-nerve barrier (BNB and pain, focusing on cellular and molecular mechanisms of BBB permeabilization induced by inflammatory or neuropathic pain and migraine.

  3. Converse Barrier Certificate Theorems

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer

    2016-01-01

    This paper shows that a barrier certificate exists for any safe dynamical system. Specifically, we prove converse barrier certificate theorems for a class of structurally stable dynamical systems. Other authors have developed a related result by assuming that the dynamical system has neither...

  4. Skin barrier function

    DEFF Research Database (Denmark)

    2016-01-01

    Renowned experts present the latest knowledge Although a very fragile structure, the skin barrier is probably one of the most important organs of the body. Inward/out it is responsible for body integrity and outward/in for keeping microbes, chemicals, and allergens from penetrating the skin. Since...... the role of barrier integrity in atopic dermatitis and the relationship to filaggrin mutations was discovered a decade ago, research focus has been on the skin barrier, and numerous new publications have become available. This book is an interdisciplinary update offering a wide range of information...... on the subject. It covers new basic research on skin markers, including results on filaggrin and on methods for the assessment of the barrier function. Biological variation and aspects of skin barrier function restoration are discussed as well. Further sections are dedicated to clinical implications of skin...

  5. Barriers to the future

    Energy Technology Data Exchange (ETDEWEB)

    Massey, C T

    1986-09-01

    Opportunities for the British coal industry seem vast yet there are still barriers to progress. Seven areas are identified and discussed: mining mobility (for example, longwall mining systems are rigid and inflexible compared with American stall and pillar working); mine structure (many mines are more suitable to pit ponies than to large pieces of equipment); financial barriers (Government requires the industry to break even in 1987/88); personnel barriers (less specialization, better use of skills); safety barriers (increased use of remote control, ergonomics and robotics to protect workers); microelectronic management (nationalization has cushioned management from the market place; there is a need for a more multidisciplinary approach to the industry); and legal barriers (most legislation in the past has been in response to accidents; legislation external to the industry but affecting it is more fundamental).

  6. Vehicle barrier systems

    International Nuclear Information System (INIS)

    Sena, P.A.

    1986-01-01

    The ground vehicle is one of the most effective tools available to an adversary force. Vehicles can be used to penetrate many types of perimeter barriers, transport equipment and personnel rapidly over long distances, and deliver large amounts of explosives directly to facilities in suicide missions. The function of a vehicle barrier system is to detain or disable a defined threat vehicle at a selected distance from a protected facility. Numerous facilities are installing, or planning to install, vehicle barrier systems and many of these facilities are requesting guidance to do so adequately. Therefore, vehicle barriers are being evaluated to determine their stopping capabilities so that systems can be designed that are both balanced and capable of providing a desired degree of protection. Equally important, many of the considerations that should be taken into account when establishing a vehicle barrier system have been identified. These considerations which pertain to site preparation, barrier selection, system integration and operation, and vehicle/barrier interaction, are discussed in this paper

  7. Converse Barrier Certificate Theorem

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer

    2013-01-01

    This paper presents a converse barrier certificate theorem for a generic dynamical system.We show that a barrier certificate exists for any safe dynamical system defined on a compact manifold. Other authors have developed a related result, by assuming that the dynamical system has no singular...... points in the considered subset of the state space. In this paper, we redefine the standard notion of safety to comply with generic dynamical systems with multiple singularities. Afterwards, we prove the converse barrier certificate theorem and illustrate the differences between ours and previous work...

  8. Information barriers and authentication

    International Nuclear Information System (INIS)

    MacArthur, D.W.; Wolford, J.K.

    2001-01-01

    Acceptance of nuclear materials into a monitoring regime is complicated if the materials are in classified shapes or have classified composition. An attribute measurement system with an information barrier can be emplo,yed to generate an unclassified display from classified measurements. This information barrier must meet two criteria: (1) classified information cannot be released to the monitoring party, and (2) the monitoring party must be convinced that the unclassified output accurately represents the classified input. Criterion 1 is critical to the host country to protect the classified information. Criterion 2 is critical to the monitoring party and is often termed the 'authentication problem.' Thus, the necessity for authentication of a measurement system with an information barrier stems directly from the description of a useful information barrier. Authentication issues must be continually addressed during the entire development lifecycle of the measurement system as opposed to being applied only after the system is built.

  9. Barrier Infrared Detector (BIRD)

    Data.gov (United States)

    National Aeronautics and Space Administration — A recent breakthrough in MWIR detector design, has resulted in a high operating temperature (HOT) barrier infrared detector (BIRD) that is capable of spectral...

  10. Protective barrier development: Overview

    International Nuclear Information System (INIS)

    Wing, N.R.; Gee, G.W.

    1990-01-01

    Protective barrier and warning marker systems are being developed to isolate wastes disposed of near the earth's surface at the Hanford Site. The barrier is designed to function in an arid to semiarid climate, to limit infiltration and percolation of water through the waste zone to near-zero, to be maintenance free, and to last up to 10,000 yr. Natural materials (e.g., fine soil, sand, gravel, riprap, clay, asphalt) have been selected to optimize barrier performance and longevity and to create an integrated structure with redundant features. These materials isolate wastes by limiting water drainage; reducing the likelihood of plant, animal, and human intrusion; controlling emission of noxious gases; and minimizing erosion. Westinghouse Hanford Company and Pacific Northwest Laboratory efforts to assess the performance of various barrier and marker designs will be discussed

  11. Engineered barriers: current status

    International Nuclear Information System (INIS)

    Atkinson, A.; Marsh, G.P.

    1988-01-01

    This report summarises the current state of research relevant to assessing the performance of engineered barriers made of steel and concrete in radioactive waste repositories. The objective of these barriers is to contain the radionuclides within them by providing both physical and chemical impediment to their release. The physical barriers are of most value for highly soluble isotopes with relatively short half-lives (eg 137 Cs), since they can provide containment until a large fraction of the activity has decayed. In addition they can facilitate retrievability for some period after disposal. The chemical barriers operate by beneficial conditioning of the near field groundwater and providing sites for sorption of radionuclides. Both of these reduce the aqueous concentration of radionuclides in the near field. (author)

  12. Skin barrier composition

    International Nuclear Information System (INIS)

    Osburn, F.G.

    1985-01-01

    A skin barrier composition comprises a mixture of a copolymer resin of ethylene and vinyl acetate (EVA), and a water-insoluble dry tack-providing elastomer such as polyisobutylene. The composition after mixing and molding, is subjected to ionizing irradiation to form cross-linked polymer networks of the EVA. The compositions have exceptional properties for use as barrier sheets, rings, or strips in ostomy, wound drainage, and incontinence devices. (author)

  13. Skin barrier composition

    Energy Technology Data Exchange (ETDEWEB)

    Osburn, F G

    1985-06-12

    A skin barrier composition comprises a mixture of a copolymer resin of ethylene and vinyl acetate (EVA), and a water-insoluble dry tack-providing elastomer such as polyisobutylene. The composition after mixing and molding, is subjected to ionizing irradiation to form cross-linked polymer networks of the EVA. The compositions have exceptional properties for use as barrier sheets, rings, or strips in ostomy, wound drainage, and incontinence devices.

  14. Fuzzy barrier distributions

    International Nuclear Information System (INIS)

    Piasecki, E.

    2009-01-01

    Heavy-ion collisions often produce a fusion barrier distribution with structures displaying a fingerprint of couplings to highly collective excitations [1]. Basically the same distribution can be obtained from large-angle quasi-elastic scattering, though here the role of the many weak direct-reaction channels is unclear. For 2 0N e + 9 0Z r we have observed the barrier structures expected for the highly deformed neon projectile, but for 2 0N e + 9 2Z r we find completely smooth distribution (see Fig.1). We find that transfer channels in these systems are of similar strength but single particle excitations are significantly stronger in the latter case. They apparently reduce the 'resolving power' of the quasi-elastic channel, what leads to smeared out, or 'fuzzy' barrier distribution. This is the first case when such a phenomenon has been observed.(author)

  15. Health Barriers to Learning

    Directory of Open Access Journals (Sweden)

    Delaney Gracy

    2014-01-01

    Full Text Available This article summarizes the results from a 2013 online survey with 408 principals and assistant principals in New York City public elementary and middle schools. The survey assessed three primary areas: health issues in the school, health issues perceived as barriers to learning for affected students, and resources needed to address these barriers. Eighteen of the 22 health conditions listed in the survey were considered a moderate or serious issue within their schools by at least 10% of respondents. All 22 of the health issues were perceived as a barrier to learning by between 12% and 87% of the respondents. Representatives from schools that serve a higher percentage of low-income students reported significantly higher levels of concern about the extent of health issues and their impact on learning. Respondents most often said they need linkages with organizations that can provide additional services and resources at the school, especially for mental health.

  16. Barrier Data Base user's guide

    International Nuclear Information System (INIS)

    Worrell, R.B.; Gould, D.J.; Wall, D.W.

    1977-06-01

    A special purpose data base for physical security barriers has been developed. In addition to barriers, the entities accommodated by the Barrier Data Base (BDB) include threats and references. A threat is established as a configuration of people and equipment which has been employed to penetrate (or attempt to penetrate) a barrier. References are used to cite publications pertinent to the barriers and threats in the data base. Utilization and maintenance of the Barrier Data Base is achieved with LIST, QUERY, ENTER, DELETE, and CHANGE commands which are used to manipulate the data base entities

  17. Geophysical characterization of subsurface barriers

    International Nuclear Information System (INIS)

    Borns, D.J.

    1995-08-01

    An option for controlling contaminant migration from plumes and buried waste sites is to construct a subsurface barrier of a low-permeability material. The successful application of subsurface barriers requires processes to verify the emplacement and effectiveness of barrier and to monitor the performance of a barrier after emplacement. Non destructive and remote sensing techniques, such as geophysical methods, are possible technologies to address these needs. The changes in mechanical, hydrologic and chemical properties associated with the emplacement of an engineered barrier will affect geophysical properties such a seismic velocity, electrical conductivity, and dielectric constant. Also, the barrier, once emplaced and interacting with the in situ geologic system, may affect the paths along which electrical current flows in the subsurface. These changes in properties and processes facilitate the detection and monitoring of the barrier. The approaches to characterizing and monitoring engineered barriers can be divided between (1) methods that directly image the barrier using the contrasts in physical properties between the barrier and the host soil or rock and (2) methods that reflect flow processes around or through the barrier. For example, seismic methods that delineate the changes in density and stiffness associated with the barrier represents a direct imaging method. Electrical self potential methods and flow probes based on heat flow methods represent techniques that can delineate the flow path or flow processes around and through a barrier

  18. Chaotic correlations in barrier billiards with arbitrary barriers

    International Nuclear Information System (INIS)

    Osbaldestin, A H; Adamson, L N C

    2013-01-01

    We study autocorrelation functions in symmetric barrier billiards for golden mean trajectories with arbitrary barriers. Renormalization analysis reveals the presence of a chaotic invariant set and thus that, for a typical barrier, there are chaotic correlations. The chaotic renormalization set is the analogue of the so-called orchid that arises in a generalized Harper equation. (paper)

  19. Design of engineered sorbent barriers

    International Nuclear Information System (INIS)

    Jones, E.O.; Freeman, H.D.

    1988-08-01

    A sorbent barrier uses sorbent material such as activated carbon or natural zeolites to prevent the migration of radionuclides from a low-level waste site to the aquifer. The sorbent barrier retards the movement of radioactive contaminants, thereby providing time for the radionuclides to decay. Sorbent barriers can be a simple, effective, and inexpensive method for reducing the migration of radionuclides to the environment. Designing a sorbent barrier consists of using soil and sorbent material properties and site conditions as input to a model which will determine the necessary sorbent barrier thickness to meet contaminant limits. The paper will cover the following areas: techniques for measuring sorption properties of barrier materials and underlying soils, use of a radionuclide transport model to determine the required barrier thickness and performance under a variety of site conditions, and cost estimates for applying the barrier. 8 refs., 6 figs., 1 tab

  20. Design of engineered sorbent barriers

    International Nuclear Information System (INIS)

    Jones, E.O.; Freeman, H.D.

    1988-01-01

    A sorbent barrier uses sorbent material such as activated carbon or natural zeolites to prevent the migration of radionuclides from a low-level waste site to the aquifer. The sorbent barrier retards the movement of radioactive contaminants, thereby providing time for the radionuclides to decay. Sorbent barriers can be a simple, effective, and inexpensive method for reducing the migration of radionuclides to the environment. Designing a sorbent barrier consists of using soil and sorbent material properties and site conditions as input to a model which will determine the necessary sorbent barrier thickness to meet contaminant limits. The paper covers the following areas: techniques for measuring sorption properties of barrier materials and underlying soils, use of a radionuclide transport model to determine the required barrier thickness and performance under a variety of site conditions, and cost estimates for applying the barrier

  1. Shottky-barrier formation

    International Nuclear Information System (INIS)

    Guines, F.; Sanchez-Dehesa, J.; Flores, F.

    1983-01-01

    In this paper a realistic selfconsistent calculation of an abrupt metal-semiconductor junction is presented by means of a tight-binding approach. A specific Si-Ag junction has been considered, and the charge neutrality level as well as the barrier height have been determined in good agreement with experiments. For a generaljunction it is shown that the interface properties depend essentially on the characteristics of the first metal layer and its interaction with the semiconductor. (Author) [pt

  2. Energy barrier to decoherence

    International Nuclear Information System (INIS)

    Mizel, Ari; Mitchell, M. W.; Cohen, Marvin L.

    2001-01-01

    We propose a ground-state approach to realizing quantum computers. This scheme is time-independent and inherently defends against decoherence by possessing an energy barrier to excitation. We prove that our time-independent qubits can perform the same algorithms as their time-dependent counterparts. Advantages and disadvantages of the time-independent approach are described. A model involving quantum dots is provided for illustration

  3. Performance of engineered barriers

    International Nuclear Information System (INIS)

    Rajaram, V.; Dean, P.V.; McLellan, S.A.

    1997-01-01

    Engineered barriers, both vertical and horizontal, have been used to isolate hazardous wastes from contact, precipitation, surface water and groundwater. The primary objective of this study was to determine the performance of subsurface barriers installed throughout the U.S. over the past 20 years to contain hazardous wastes. Evaluation of Resource Conservation and Recovery Act (RCRA) Subtitle C or equivalent caps was a secondary objective. A nationwide search was launched to select hazardous waste sites at which vertical barrier walls and/or caps had been used as the containment method. None of the sites selected had an engineered floor. From an initial list of 130 sites, 34 sites were selected on the basis of availability of monitoring data for detailed analysis of actual field performance. This paper will briefly discuss preliminary findings regarding the design, construction quality assurance/construction quality control (CQA/CQC), and monitoring at the 34 sites. In addition, the short-term performance of these sites (less than 5 years) is presented since very little long-term performance data was available

  4. Fluctuations in Schottky barrier heights

    International Nuclear Information System (INIS)

    Mahan, G.D.

    1984-01-01

    A double Schottky barrier is often formed at the grain boundary in polycrystalline semiconductors. The barrier height is shown to fluctuate in value due to the random nature of the impurity positions. The magnitude of the fluctuations is 0.1 eV, and the fluctuations cause the barrier height measured by capacitance to differ from the one measured by electrical conductivity

  5. Barrier mechanisms in the Drosophila blood-brain barrier

    Directory of Open Access Journals (Sweden)

    Samantha Jane Hindle

    2014-12-01

    Full Text Available The invertebrate blood-brain barrier field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through GPCR signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate blood-brain barrier has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many blood-brain barrier mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the blood-brain barrier can govern whole animal physiologies. This includes novel functions of blood-brain barrier gap junctions in orchestrating synchronized neuroblast proliferation, and of blood-brain barrier secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate blood-brain barrier anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study.

  6. Barriers to accessing urethroplasty.

    Science.gov (United States)

    Consolo, Michael J; Syed, Kirin K; Robison, Christopher; McFadden, Jacob; Shalowitz, David I; Brown, Gordon A; Sussman, David O; Figler, Bradley D

    2016-01-01

    Urethroplasty is an effective treatment for men with anterior urethral strictures, but is utilized less frequently than ineffective treatments such as internal urethrotomy. We sought to identify provider-level barriers to urethroplasty. An anonymous online survey was emailed to all Mid-Atlantic American Urological Association members. Six scenarios in which urethroplasty was the most appropriate treatment were presented. Primary outcome was recommendation for urethroplasty in ≥ three clinical scenarios. Other factors measured include practice zip code, urethroplasty training, and proximity to a urethroplasty surgeon. Multivariate logistic regression identified factors associated with increased likelihood of urethroplasty recommendation. Of 670 members emailed, 109 (16%) completed the survey. Final analysis included 88 respondents. Mean years in practice was 17.2. Most respondents received formal training in urethroplasty: 43 (49%) in residency, 5 (6%) in fellowship, and 10 (11%) in both; 48 respondents (55%) had a urethroplasty surgeon in their practice, whereas 18 (20%) had a urethroplasty surgeon within 45 minutes of his or her primary practice location. The only covariate that was associated with an increased likelihood of recommending urethroplasty in ≥ three scenarios was formal urethroplasty training. Most members (68%) reported no barriers to referring patients for urethroplasty; the most common barriers cited were long distance to urethroplasty surgeon (n 5 13, 15%) and concern about complications (n 5 8, 9%). Urethroplasty continues to be underutilized in men with anterior urethral strictures, potentially due to lack of knowledge dissemination and access to a urethroplasty surgeon. Appropriate urethroplasty utilization may increase with greater exposure to urethroplasty in training.

  7. Racial Trade Barriers?

    DEFF Research Database (Denmark)

    Bjerre, Jacob Halvas

    . This paper analyzes the racial policies pursued in the foreign trade and argues that we need to recognize Aryanization as a world-wide policy in order to fully understand its character and possible consequences. I focus on the pre-war period and analyze the case of Denmark from three different perspectives......: perpetrators, victims and bystanders. The analysis will show that race, economy and foreign trade were combined in an attempt to raise racial trade barriers. This forced the question of German racial policies on the Danish government, Danish-Jewish businesses, and German companies involved in foreign trade...

  8. Support or Barrier?

    DEFF Research Database (Denmark)

    Sanden, Guro Refsum; Lønsmann, Dorte

    This study offers a critical look at how corporate-level language management influences front-line language practices among employees in three multinational corporations (MNCs) headquartered in Scandinavia. Based on interview and document data, we examine, firstly, what front-line practices...... employees use to cross language boundaries in their everyday work, and, secondly, how these practices relate to top-down language management in the case companies. Our findings show that employees are often dependent on ad hoc and informal solutions in cross- language situations, which leads us...... to a discussion of how a company’s language policy may be seen as both support and a barrier....

  9. Stability of barrier buckets with zero RF-barrier separations

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K.Y.; /Fermilab

    2005-03-01

    A barrier bucket with very small separation between the rf barriers (relative to the barrier widths) or even zero separation has its synchrotron tune decreasing rather slowly from a large value towards the boundary of the bucket. As a result, large area at the bucket edges can become unstable under the modulation of rf voltage and/or rf phase. In addition, chaotic regions may form near the bucket center and extend outward under increasing modulation. Application is made to those barrier buckets used in the process of momentum mining at the Fermilab Recycler Ring.

  10. Performing a local barrier operation

    Science.gov (United States)

    Archer, Charles J; Blocksome, Michael A; Ratterman, Joseph D; Smith, Brian E

    2014-03-04

    Performing a local barrier operation with parallel tasks executing on a compute node including, for each task: retrieving a present value of a counter; calculating, in dependence upon the present value of the counter and a total number of tasks performing the local barrier operation, a base value, the base value representing the counter's value prior to any task joining the local barrier; calculating, in dependence upon the base value and the total number of tasks performing the local barrier operation, a target value of the counter, the target value representing the counter's value when all tasks have joined the local barrier; joining the local barrier, including atomically incrementing the value of the counter; and repetitively, until the present value of the counter is no less than the target value of the counter: retrieving the present value of the counter and determining whether the present value equals the target value.

  11. Barrier rf systems in synchrotrons

    International Nuclear Information System (INIS)

    Bhat, Chandra M.

    2004-01-01

    Recently, many interesting applications of the barrier RF system in hadron synchrotrons have been realized. A remarkable example of this is the development of longitudinal momentum mining and implementation at the Fermilab Recycler for extraction of low emittance pbars for the Tevatron shots. At Fermilab, we have barrier RF systems in four different rings. In the case of Recycler Ring, all of the rf manipulations are carried out using a barrier RF system. Here, the author reviews various uses of barrier rf systems in particle accelerators including some new schemes for producing intense proton beam and possible new applications

  12. Tunnel superpenetrability of potential barriers

    International Nuclear Information System (INIS)

    Zakhariev, B N.

    1982-01-01

    The transmission of two particles through the same barrier is considered. The limiting cases are compared when the particles are joined together in a single particle with double mass-energy and potential and when they pass the barrier independently. As an intermediate case a pair of particles bound in a quasideuteron of a finite size is considered. It is shown that long-range collective correlations of particles (of the superfluidity type and others) simplify very much for them passing through high potential barriers. This happens due to the transfer of the additional energy from the particles outside the barriers to those inside it

  13. Barriers for recess physical activity

    DEFF Research Database (Denmark)

    Pawlowski, Charlotte Skau; Tjørnhøj-Thomsen, Tine; Schipperijn, Jasper

    2014-01-01

    BACKGROUND: Many children, in particular girls, do not reach the recommended amount of daily physical activity. School recess provides an opportunity for both boys and girls to be physically active, but barriers to recess physical activity are not well understood. This study explores gender...... differences in children's perceptions of barriers to recess physical activity. Based on the socio-ecological model four types of environmental barriers were distinguished: natural, social, physical and organizational environment. METHODS: Data were collected through 17 focus groups (at 17 different schools...... this study, we recommend promoting recess physical activity through a combination of actions, addressing barriers within the natural, social, physical and organizational environment....

  14. Linguistic Barriers and Bridges

    DEFF Research Database (Denmark)

    Thuesen, Frederik

    2016-01-01

    The influence of language on social capital in low-skill and ethnically diverse workplaces has thus far received very limited attention within the sociology of work. As the ethnically diverse workplace is an important social space for the construction of social relations bridging different social...... groups, the sociology of work needs to develop a better understanding of the way in which linguistic diversity influences the formation of social capital, i.e. resources such as the trust and reciprocity inherent in social relations in such workplaces. Drawing on theories about intergroup contact...... and intercultural communication, this article analyses interviews with 31 employees from two highly ethnically diverse Danish workplaces. The article shows how linguistic barriers such as different levels of majority language competence and their consequent misunderstandings breed mistrust and hostility, whilst...

  15. Countermeasures and barriers

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Johannes [Oersted - DTU, Automation, Kgs. Lyngby (Denmark)

    2005-10-01

    In 1973 Haddon proposed ten strategies for reducing and avoiding damages based on a model of potential harmful energy transfer (Haddon, 1973). The strategies apply to a large variety of unwanted phenomena. Haddon's pioneering work on countermeasures has had a major influence on later thinking about safety. Considering its impact it is remarkable that the literature offers almost no discussions related to the theoretical foundations of Haddon's countermeasure strategies. The present report addresses a number of theoretical issues related to Haddon's countermeasure strategies, which are: 1) A reformulation and formalization of Haddon's countermeasure strategies. 2) An identification and description of some of the problems associated with the term 'barrier'. 3) Suggestions for a more precise terminology based on the causal structure of countermeasures. 4) Extending the scope of countermeasures to include sign-based countermeasures. (au)

  16. Countermeasures and barriers

    International Nuclear Information System (INIS)

    Petersen, Johannes

    2005-10-01

    In 1973 Haddon proposed ten strategies for reducing and avoiding damages based on a model of potential harmful energy transfer (Haddon, 1973). The strategies apply to a large variety of unwanted phenomena. Haddon's pioneering work on countermeasures has had a major influence on later thinking about safety. Considering its impact it is remarkable that the literature offers almost no discussions related to the theoretical foundations of Haddon's countermeasure strategies. The present report addresses a number of theoretical issues related to Haddon's countermeasure strategies, which are: 1) A reformulation and formalization of Haddon's countermeasure strategies. 2) An identification and description of some of the problems associated with the term 'barrier'. 3) Suggestions for a more precise terminology based on the causal structure of countermeasures. 4) Extending the scope of countermeasures to include sign-based countermeasures. (au)

  17. Thames barrier (flood protection barriers on the Thames)

    International Nuclear Information System (INIS)

    Ilkovic, J.

    2005-01-01

    In this paper the flood protection barriers on the Thames are presented. The flood protection system on the Thames in 1984 was commissioned. During two decades this barrier was used 54 times against to the high water and 34 times against storm-sewage. There is installed buttress type hydroelectric power plant

  18. Energy barriers in patterned media

    NARCIS (Netherlands)

    de Vries, Jeroen

    2013-01-01

    Due to the fact that thermal activation aids in overcoming the energy barrier, the required field for reversal varies from instance to instance for the same island. This thermally induced switching field distribution can be used to determine the difference in energy barrier of magneticallyweak and

  19. Simulating complex noise barrier reflections

    NARCIS (Netherlands)

    Eerden, F.J.M. van der; Lutgendorf, D.; Roo, F. de

    2011-01-01

    Within the EU FP7 QUIESST project, QUIeting the Environment for a Sustainable Surface Transport, a test method is being developed for the reflectivity of noise barriers. The method needs to account for a complex shape of barriers and the use of various types of absorbing materials. The performance

  20. BARRIERS OF STRATEGIC ALLIANCES ORGANIZATION

    Directory of Open Access Journals (Sweden)

    Vladislav M. Sannikov

    2014-01-01

    Full Text Available General barriers of organization of different types of strategic alliances have beenconsidered in the article. There are several recommendations for overcoming themin cases of international alliances, and in case of work in one state. The article also identified goals and tasks of single coordination center of alliance to overcome organization barriers.

  1. Tunnelling without barriers

    International Nuclear Information System (INIS)

    Lee, K.

    1987-01-01

    The evolution in flat and curved space-time of quantum fields in theories with relative flat potential and its consequences are considered. It is shown that bubble nucleation, a quantum mechanical tunnelling process, may occur in flat space-time, having a bounce solution, even if V(phi) has no barrier. It is shown that bubble nucleation can also occur in curved space-time even though there is no bounce solution in the standard formalism for the bubble nucleation rate in curved space-time. Additionally, bubbles can nucleate during the slow rolling period on the potential in flat and curved space-time, in this case also there is no bounce solution. It is known in the new inflationary scenario that energy density perturbations caused by quantum fluctuations of the scalar field can satisfy the presently observed bounds on density perturbations. Bubble nucleation during the slow rolling period also gives rise to density perturbations. For a model potential density perturbations by bubbles are calculated at the horizon reentering. By applying the bound from the almost isotropic microwave black body radiation on these density perturbations, a constraint on the model potential is obtained. Finally, some further implications on the galaxy formation and applications in more realistic potential are discussed

  2. Development of engineered barrier

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwan Sik; Cho, Won Jin; Lee, Jae Owan; Kim, Seung Soo; Kang, Mu Ja

    1999-03-01

    Engineered barrier development was carried out into the three research fields : waste form, disposal container, and buffer. The waste form field dealt with long-term leaching tests with borosilicate waste glasses surrounded by compacted bentonite. The leach rate decreased with increasing time, and was higher for the waste specimen rich in U and Na. In the container field, preliminary concepts of disposal containers were recommended by conducting structural analysis, thermal analysis, and shielding analysis, and major properties of stainless steel, copper, and titanium as a container material were surveyed. The sensitization degrees of SUS 316 and316L were lower than those of SUS 304 and 304L, respectively. The crevice corrosion of sensitized stainless steel was sensitive to the content of salt. Researches into the buffer included establishment of its performance criteria followed by investigating major properties of buffer using potential material in Korea. Experiments were made for measuring hydraulic conductivities, swelling properties, mechanical properties, thermal conductivities, pore-water chemistry properties, and adsorption properties was also investigated. (author)

  3. Omnidirectional ventilated acoustic barrier

    Science.gov (United States)

    Zhang, Hai-long; Zhu, Yi-fan; Liang, Bin; Yang, Jing; Yang, Jun; Cheng, Jian-chun

    2017-11-01

    As an important problem in acoustics, sound insulation finds applications in a great variety of situations. In the existing schemes, however, there has always been a trade-off between the thinness of sound-insulating devices and their ventilating capabilities, limiting their potentials in the control of low-frequency sound in high ventilation environments. Here, we design and experimentally implement an omnidirectional acoustic barrier with a planar profile, subwavelength thickness ( 0.18 λ ), yet high ventilation. The proposed mechanism is based on the interference between the resonant scattering of discrete states and the background scattering of continuous states which induces a Fano-like asymmetric transmission profile. Benefitting from the binary-structured design of the coiled unit and hollow pipe, it maximally simplifies the design and fabrication while ensuring the ventilation for all the non-resonant units with open tubes. The simulated and measured results agree well, showing the effectiveness of our proposed mechanism to block low frequency sound coming from various directions while allowing 63% of the air flow to pass. We anticipate our design to open routes to design sound insulators and to enable applications in traditionally unattainable cases such as those calling for noise reduction and cooling simultaneously.

  4. Alternative geochemical barrier materials

    International Nuclear Information System (INIS)

    1991-07-01

    Previous investigations of the effects of neutralization and reduction on uranium mill tailings pore fluids by the Technical Support Contractor indicated that arsenic, selenium, and molybdenum continue to remain in solution in all but reducing conditions. These hazardous constituents are present in groundwaters as oxyanions and, therefore, are not expected to be removed by adsorption into clays and most other soil constituents. It was decided to investigate the attenuation capacity of two commonly available crystalline iron oxides, taconite and scoria, and a zeolite, a network aluminosilicate with a cage structure. Columns of the candidate materials were exposed to solutions of individual constituents, including arsenic, molybdenum, selenium, and, uranium, and to the spiked tailings pore fluid from the Bodo Canyon disposal cell near Durango, Colorado. In addition to the single material columns, a homogeneous blend of the three materials and layers of the materials were exposed to spiked tailings pore fluids. The results of these experiments indicate that with the exception of molybdenum, the constituents of concern are attenuated by the taconite; however, they are not sufficiently attenuated to meet the groundwater protection standards applicable to the UMTRA Project. Therefore, the candidate barrier materials did not prove to be useful to the UMTRA Project for the cleanup of groundwaters

  5. Mobilitet, barrierer & muligheder

    DEFF Research Database (Denmark)

    Petersen, Mimi

    2011-01-01

    stereotypering. På den ene side peger udsagn fra de unge drenge på en oplevelse af at blive kriminaliseret i kraft af deres køn (det maskuline kombineret med at have en anden hudfarve). Og de unge piger oplever, at de udover at blive kategoriseret som ”indvandrere” også bliver kategoriseret som passive, umyndige...... som en vej ud af irakiske Kurdistan, men ikke tilbage til Danmark. Drengene fra familier med bedre økonomiske ressourcer giver udtryk for, ønske om at rejse til andre lande. På grund af begrænsede sproglige kompetencer oplever hovedparten af de unge (både i Danmark og i irakiske Kurdistan) barrierer i...... har planer for at flytte fra Kurdistan. De har dansk statsborgerskab, men de vil ikke tilbage til Danmark. I de fortællinger, som afhandlingen bygger på, er det tydeligt at samspillet mellem flere sociale dimensioner, spiller ind på de unges selvforståelse, tilhørsforhold, erfaringer og deres valg af...

  6. Development of engineered barrier

    International Nuclear Information System (INIS)

    Chun, Kwan Sik; Cho, Won Jin; Lee, Jae Owan; Kim, Seung Soo; Kang, Mu Ja

    1999-03-01

    Engineered barrier development was carried out into the three research fields : waste form, disposal container, and buffer. The waste form field dealt with long-term leaching tests with borosilicate waste glasses surrounded by compacted bentonite. The leach rate decreased with increasing time, and was higher for the waste specimen rich in U and Na. In the container field, preliminary concepts of disposal containers were recommended by conducting structural analysis, thermal analysis, and shielding analysis, and major properties of stainless steel, copper, and titanium as a container material were surveyed. The sensitization degrees of SUS 316 and 316L were lower than those of SUS 304 and 304L, respectively. The crevice corrosion of sensitized stainless steel was sensitive to the content of salt. Researches into the buffer included establishment of its performance criteria followed by investigating major properties of buffer using potential material in Korea. Experiments were made for measuring hydraulic conductivities, swelling properties, mechanical properties, thermal conductivities, pore-water chemistry properties, and adsorption properties was also investigated. (author)

  7. Tritium/hydrogen barrier development

    International Nuclear Information System (INIS)

    Hollenberg, G.W.; Simonen, E.P.; Kalinen, G.; Terlain, A.

    1994-06-01

    A review of hydrogen permeation barriers that can be applied to structural metals used in fusion power plants is presented. Both implanted and chemically available hydrogen isotopes must be controlled in fusion plants. The need for permeation barriers appears strongest in Li17-Pb blanket designs, although barriers also appear necessary for other blanket and coolant systems. Barriers that provide greater than a 1000 fold reduction in the permeation of structural metals are desired. In laboratory experiments, aluminide and titanium ceramic coatings provide permeation reduction factors, PRFS, from 1000 to over 100,000 with a wide range of scatter. The rate-controlling mechanism for hydrogen permeation through these barriers may be related to the number and type of defects in the barriers. Although these barriers appear robust and resistant to liquid metal corrosion, irradiation tests which simulate blanket environments result in very low PRFs in comparison to laboratory experiments, i.e., <150. It is anticipated from fundamental research activities that the REID enhancement of hydrogen diffusion in oxides may contribute to the lower permeation reduction factors during in-reactor experiments

  8. Enershield : energy saving air barriers

    Energy Technology Data Exchange (ETDEWEB)

    Hallihan, D. [Enershield Industries Ltd., Edmonton, AB (Canada)

    2008-07-01

    Enershield Industries is a leader in air barrier technology and provides solution for the Canadian climate. This presentation described the advantages of air barriers and the impact of rising energy costs. An air barrier is used to separate areas of differing environments and makes existing building systems more efficient. This presentation discussed how an air barrier works. It also identified how Enershield Industries calculates energy savings. It described air barrier applications and those who use barrier technology. These include the commercial and industrial sector as well as the personnel and retail sector. Barrier technology can be used for cold storage; vehicle and equipment washes; food processing; and environmental separation. Features and benefits such as the ability to create seal, acoustic insulation, and long term durability were also discussed. Last, the presentation addressed model selection and design criteria issues. Design criteria that were presented included a discussion of acoustic installation, articulating nozzles, scroll cased fans, and structural frame. Other design criteria presented were galvanized frames, telescopic sliders, and off the shelf parts. It was concluded that the ability to reduce energy consumption and enhance employee/client comfort is beneficial to the employer as well as to the employee. figs.

  9. Penetration through the Skin Barrier

    DEFF Research Database (Denmark)

    Nielsen, Jesper Bo; Benfeldt, Eva; Holmgaard, Rikke

    2016-01-01

    The skin is a strong and flexible organ with barrier properties essential for maintaining homeostasis and thereby human life. Characterizing this barrier is the ability to prevent some chemicals from crossing the barrier while allowing others, including medicinal products, to pass at varying rates......-through diffusion cells) as well as in vivo methods (microdialysis and microperfusion). Then follows a discussion with examples of how different characteristics of the skin (age, site and integrity) and of the penetrants (size, solubility, ionization, logPow and vehicles) affect the kinetics of percutaneous...

  10. Vehicle barrier with access delay

    Science.gov (United States)

    Swahlan, David J; Wilke, Jason

    2013-09-03

    An access delay vehicle barrier for stopping unauthorized entry into secure areas by a vehicle ramming attack includes access delay features for preventing and/or delaying an adversary from defeating or compromising the barrier. A horizontally deployed barrier member can include an exterior steel casing, an interior steel reinforcing member and access delay members disposed within the casing and between the casing and the interior reinforcing member. Access delay members can include wooden structural lumber, concrete and/or polymeric members that in combination with the exterior casing and interior reinforcing member act cooperatively to impair an adversarial attach by thermal, mechanical and/or explosive tools.

  11. Big Data as Information Barrier

    Directory of Open Access Journals (Sweden)

    Victor Ya. Tsvetkov

    2014-07-01

    Full Text Available The article covers analysis of ‘Big Data’ which has been discussed over last 10 years. The reasons and factors for the issue are revealed. It has proved that the factors creating ‘Big Data’ issue has existed for quite a long time, and from time to time, would cause the informational barriers. Such barriers were successfully overcome through the science and technologies. The conducted analysis refers the “Big Data” issue to a form of informative barrier. This issue may be solved correctly and encourages development of scientific and calculating methods.

  12. Fusion barrier characteristics of actinides

    Science.gov (United States)

    Manjunatha, H. C.; Sridhar, K. N.

    2018-03-01

    We have studied fusion barrier characteristics of actinide compound nuclei with atomic number range 89 ≤ Z ≤ 103 for all projectile target combinations. After the calculation of fusion barrier heights and positions, we have searched for their parameterization. We have achieved the empirical formula for fusion barrier heights (VB), positions (RB), curvature of the inverted parabola (ħω) of actinide compound nuclei with atomic number range 89 ≤ Z ≤ 103 for all projectile target combinations (6 projectile target combinations. The values produced by the present formula are also compared with experiments. The present pocket formula produces fusion barrier characteristics of actinides with the simple inputs of mass number (A) and atomic number (Z) of projectile-targets.

  13. Transport barrier in Helical system

    International Nuclear Information System (INIS)

    Ida, Katsumi

    1998-01-01

    Experiments on the transport barrier in Helical plasmas are reviewed. There are two mechanisms of transport improvement, that results in the formation of the transport barrier. One is the improvement of neoclassical transport by reducing the ripple loss with radial electric field, which exist only in helical plasma. The other is the improvement of anomalous transport due to the suppression of fluctuations associated with a radial electric field shear both in tokamak and helical plasma. The formation of the transport barrier can be triggered by the radial electric field shear associated with the transition of the radial electric field (L/H transition or ion-electron root transition) or the peaked density or the optimization of magnetic field shear. The mechanisms of transport barrier formation are also discussed. (author). 60 refs

  14. Coastal Structures and Barriers 2012

    Data.gov (United States)

    California Natural Resource Agency — This dataset is a compilation of the UCSC Sand Retention Structures, MC Barriers, and USACE Coastal Structures. UCSC Sand Retention Structures originate from a...

  15. Engineered barriers: current status 1989

    International Nuclear Information System (INIS)

    Atkinson, A.; Marsh, G.B.

    1989-06-01

    This report summarises the current state of research relevant to assessing the performance of engineered barriers made of steel and concrete in radioactive waste repositories. The objective of these barriers is to contain substantially the radionuclides within them by providing both physical and chemical impediment to their release. The physical barriers are of most value for highly soluble isotopes with relatively short half-lives (eg 137 Cs), since they can provide a measure of containment until a large fraction of the activity has decayed. In addition they can facilitate retrievability for some period after disposal. The chemical barriers operate by beneficial conditioning of the near field groundwater and providing sites for sorption of radionuclides. Both of these reduce the aqueous concentration of radionuclides in the near field. (author)

  16. Numerical simulation of flood barriers

    Science.gov (United States)

    Srb, Pavel; Petrů, Michal; Kulhavý, Petr

    This paper deals with testing and numerical simulating of flood barriers. The Czech Republic has been hit by several very devastating floods in past years. These floods caused several dozens of causalities and property damage reached billions of Euros. The development of flood measures is very important, especially for the reduction the number of casualties and the amount of property damage. The aim of flood control measures is the detention of water outside populated areas and drainage of water from populated areas as soon as possible. For new flood barrier design it is very important to know its behaviour in case of a real flood. During the development of the barrier several standardized tests have to be carried out. Based on the results from these tests numerical simulation was compiled using Abaqus software and some analyses were carried out. Based on these numerical simulations it will be possible to predict the behaviour of barriers and thus improve their design.

  17. Material Barriers to Diffusive Mixing

    Science.gov (United States)

    Haller, George; Karrasch, Daniel

    2017-11-01

    Transport barriers, as zero-flux surfaces, are ill-defined in purely advective mixing in which the flux of any passive scalar is zero through all material surfaces. For this reason, Lagrangian Coherent Structures (LCSs) have been argued to play the role of mixing barriers as most repelling, attracting or shearing material lines. These three kinematic concepts, however, can also be defined in different ways, both within rigorous mathematical treatments and within the realm of heuristic diagnostics. This has lead to a an ever-growing number of different LCS methods, each generally identifying different objects as transport barriers. In this talk, we examine which of these methods have actual relevance for diffusive transport barriers. The latter barriers are arguably the practically relevant inhibitors in the mixing of physically relevant tracers, such as temperature, salinity, vorticity or potential vorticity. We demonstrate the role of the most effective diffusion barriers in analytical examples and observational data. Supported in part by the DFG Priority Program on Turbulent Superstructures.

  18. Economic alternatives for containment barriers

    International Nuclear Information System (INIS)

    Nicholson, P.J.; Jasperse, B.H.; Fisher, M.J.

    1997-01-01

    Fixation, barriers, and containment of existing landfills and other disposal areas are often performed by insitu auger type soil mixing and jet grouting. Cement or other chemical reagents are mixed with soil to form both vertical and horizontal barriers. Immobilization of contaminants can be economically achieved by mixing soil and the contaminants with reagents that solidify or stabilize the contaminated area. Developed in Japan, and relatively new to the United States, the first large scale application was for a vertical barrier at the Jackson Lake Dam project in 1986. This technology has grown in both the civil and environmental field since. The paper describes current United States practice for Deep Soil Mixing (over 12 meters in depth), and Shallow Soil Mixing for vertical barriers and stabilization/solidification, and Jet Grouting for horizontal and vertical barriers. Creating very low permeability barriers at depth with minimal surface return often makes these techniques economical when compared to slurry trenches. The paper will discuss equipment, materials, soil and strength parameters, and quality control

  19. Air barrier systems: Construction applications

    Energy Technology Data Exchange (ETDEWEB)

    Perrault, J.C

    1989-01-01

    An examination is presented of how ordinary building materials can be used in an innovative manner to design, detail, and construct effective air barrier systems for common types of walls. For residential construction, the air drywall approach uses the interior gypsum board as the main component of the wall air barrier system. Joints between the gypsum board and adjacent materials or assemblies are sealed by gaskets. In commercial construction, two different techniques are employed for using gypsum board as air barrier material: the accessible drywall and non-accessible drywall approaches. The former is similar to the air drywall approach except that high performance sealants are used instead of gaskets. In the latter approach, exterior drywall sheathing is the main component of the air barrier system; joints between boards are taped and joints between boards and other components are sealed using elastomeric membrane strips. For various types of commercial and institutional buildings, metal air barrier systems are widely used and include pre-engineered curtain walls or sheet metal walls. Masonry wall systems are regarded as still the most durable, fireproof, and soundproof wall type available but an effective air barrier system has typically been difficult to implement. Factory-made elastomeric membranes offer the potential to provide airtightness to masonry walls. These membranes are applied on the entire masonry wall surface and are used to make airtight connections with other building components. Two types of product are available: thermofusible and peel-and-stick membranes. 5 figs.

  20. Diabetes and diet : managing dietary barriers

    NARCIS (Netherlands)

    Friele, R.D.

    1989-01-01

    This thesis reports on the barriers diabetic patients experience with their diet, and the ways they cope with these barriers. A dietary barrier is a hinderance to a person's well-being, induced by being advised a diet. First inventories were made of possible dietary barriers and ways of

  1. 24 CFR 574.645 - Coastal barriers.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Coastal barriers. 574.645 Section....645 Coastal barriers. In accordance with the Coastal Barrier Resources Act, 16 U.S.C. 3501, no financial assistance under this part may be made available within the Coastal Barrier Resources System. ...

  2. Programmer's description of the Barrier Data Base

    International Nuclear Information System (INIS)

    Wall, D.W.; Jones, R.E.; Worrell, R.B.

    1976-12-01

    The Barrier Data Base is a body of information concerning different kinds of barriers that are used in safeguarding nuclear materials and installations. The two programs written for creating, updating, and manipulating the Barrier Data Base are discussed. The BARRIER program is used to add, delete, modify, display, or search for specific data in the data base. A utility program named NUMBER is used to compress and renumber the barrier and threat tables

  3. Skin Barrier Function and Allergens

    DEFF Research Database (Denmark)

    Engebretsen, Kristiane Aasen; Thyssen, Jacob Pontoppidan

    2016-01-01

    The skin is an important barrier protecting us from mechanical insults, microorganisms, chemicals and allergens, but, importantly, also reducing water loss. A common hallmark for many dermatoses is a compromised skin barrier function, and one could suspect an elevated risk of contact sensitization...... and skin barrier status. Psoriasis has traditionally been regarded a Th1-dominated disease, but the discovery of Th17 cells and IL-17 provides new and interesting information regarding the pathogenesis of the disease. Research suggests an inverse relationship between psoriasis and CA, possibly due......) and Th2 (AD) have been proposed as an explanation. Finally, there is convincing evidence that exposure to irritants increases the risk of CS, and patients with ICD are, therefore, at great risk of developing CA. Skin irritation leads to the release of IL-1 and TNF-α, which affects the function of antigen...

  4. Barrier mechanisms in the Drosophila blood-brain barrier.

    Science.gov (United States)

    Hindle, Samantha J; Bainton, Roland J

    2014-01-01

    The invertebrate blood-brain barrier (BBB) field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through G-protein coupled receptor signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate BBB has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many BBB mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the BBB can govern whole animal physiologies. This includes novel functions of BBB gap junctions in orchestrating synchronized neuroblast proliferation, and of BBB secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate BBB anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study.

  5. Communication barriers in the family

    Directory of Open Access Journals (Sweden)

    BARBARA KOC-KOZŁOWIEC

    2017-10-01

    Full Text Available The art of communication – listening and speaking – is a major life skill, with a thorough influence on every human life. Remaining silent while the interlocutor speaks is not all that there is to the act of listening to messages. True listening is based on an intention to get involved in understanding of the other person, enjoying his or her presence, learning something from the conversation, giving assistance, or comforting the interlocutor. In the article the author describes obstacles (barriers, which render true listening impossible. These barriers have been identified by a group of young adults.

  6. Enhanced tunneling through nonstationary barriers

    International Nuclear Information System (INIS)

    Palomares-Baez, J. P.; Rodriguez-Lopez, J. L.; Ivlev, B.

    2007-01-01

    Quantum tunneling through a nonstationary barrier is studied analytically and by a direct numerical solution of Schroedinger equation. Both methods are in agreement and say that the main features of the phenomenon can be described in terms of classical trajectories which are solutions of Newton's equation in complex time. The probability of tunneling is governed by analytical properties of a time-dependent perturbation and the classical trajectory in the plane of complex time. Some preliminary numerical calculations of Euclidean resonance (an easy penetration through a classical nonstationary barrier due to an underbarrier interference) are presented

  7. Systems study on engineered barriers: barrier performance analysis

    International Nuclear Information System (INIS)

    Stula, R.T.; Albert, T.E.; Kirstein, B.E.; Lester, D.H.

    1980-09-01

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed

  8. Systems study on engineered barriers: barrier performance analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stula, R.T.; Albert, T.E.; Kirstein, B.E.; Lester, D.H.

    1980-09-01

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed.

  9. Barriers against psychosocial communication: oncologists' perceptions.

    Science.gov (United States)

    Fagerlind, Hanna; Kettis, Åsa; Glimelius, Bengt; Ring, Lena

    2013-10-20

    To explore oncologists' psychosocial attitudes and beliefs and their perceptions regarding barriers against psychosocial communication. A questionnaire was distributed to oncologists in Sweden (n = 537). Questions covered demography, the Physician Psychosocial Beliefs Scale (PPBS), and barriers against psychosocial communication. Stepwise multiple regression was used to determine what factors contribute the most to the PPBS score and the total number of barriers and barriers affecting clinical practice, respectively. Spearman rank-order correlation was used to determine correlation between PPBS score and number of barriers. Questionnaire response rate was 64%. Mean PPBS value was 85.5 (range, 49 to 123; SD, 13.0). Most oncologists (93%) perceived one or more barriers in communicating psychosocial aspects with patients. On average, five different communication barriers were perceived, of which most were perceived to affect clinical practice. These barriers included insufficient consultation time, lack of resources for taking care of problems discovered, and lack of methods to evaluate patients' psychosocial health in clinical practice. There was a positive correlation (rs = 0.490; P barriers (ie, less psychosocially oriented oncologists perceived more barriers). Oncologists with supplementary education with a psychosocial focus perceived fewer barriers/barriers affecting clinical practice (P barriers affecting psychosocial communication in clinical practice. Interventions aiming to improve psychosocial communication must therefore be multifaceted and individualized to clinics and individual oncologists. It is important to minimize barriers to facilitate optimal care and treatment of patients with cancer.

  10. Structure information from fusion barriers

    Indian Academy of Sciences (India)

    Pb, using the coupled reaction channel (CRC) method and correct structure information, have been analysed. The barrier distributions derived from these excitation functions including many of the significant channels are featureless, although these channels have considerable effects on the fusion excitation function.

  11. Communication Barriers in Distance Education

    Science.gov (United States)

    Isman, Aytekin; Dabaj, Fahme; Altinay, Fahriye; Altinay, Zehra

    2003-01-01

    Communication is a key concept as being the major tool for people in order to satisfy their needs. It is an activity which refers as process and effective communication requires qualified communication with the elimination of communication barriers. As it is known, distance education is a new trend by following contemporary facilities and tools…

  12. Functional barriers: Properties and evaluation

    NARCIS (Netherlands)

    Feigenbaum, A.; Dole, P.; Aucejo, S.; Dainelli, D.; Cruz Garcia, C. de la; Hankemeier, T.; N'Gono, Y.; Papaspyrides, C.D.; Paseiro, P.; Pastorelli, S.; Pavlidou, S.; Pennarun, P.Y.; Saillard, P.; Vidal, L.; Vitrac, O.; Voulzatis, Y.

    2005-01-01

    Functional barriers are multilayer structures deemed to prevent migration of some chemicals released by food-contact materials into food. In the area of plastics packaging, different migration behaviours of mono- and multilayer structures are assessed in terms of lag time and of their influence of

  13. Overcoming Barriers: Women in Superintendency

    Science.gov (United States)

    Miller, Claire M.

    2009-01-01

    Women currently represent the largest number of teachers in the United States but remain underrepresented in the superintendent position. This suggests that the superintendency has been influenced by patriarchy. If women are to break through the barriers that prevent them from attaining a superintendency, we will need to understand the social…

  14. Seasonal breaching of coastal barriers

    NARCIS (Netherlands)

    Tuan, Thieu Quang

    2007-01-01

    Natural or unintended breaching can be catastrophic, causing loss of human lives and damage to infrastructures, buildings and natural habitats. Quantitative understand-ing of coastal barrier breaching is therefore of great importance to vulnerability as-sessment of protection works as well as to

  15. Injectable barriers for waste isolation

    International Nuclear Information System (INIS)

    Persoff, P.; Finsterle, S.; Moridis, G.J.; Apps, J.; Pruess, K.; Muller, S.J.

    1995-03-01

    In this paper the authors report laboratory work and numerical simulation done in support of development and demonstration of injectable barriers formed from either of two fluids: colloidal silica or polysiloxane. Two principal problems addressed here are control of gel time and control of plume emplacement in the vadose zone. Gel time must be controlled so that the viscosity of the barrier fluid remains low long enough to inject the barrier, but increases soon enough to gel the barrier in place. During injection, the viscosity must be low enough to avoid high injection pressures which could uplift or fracture the formation. To test the grout gel time in the soil, the injection pressure was monitored as grouts were injected into sandpacks. When grout is injected into the vadose zone, it slumps under the influence of gravity, and redistributes due to capillary forces as it gels. The authors have developed a new module for the reservoir simulator TOUGH2 to model grout injection into the vadose zone, taking into account the increase of liquid viscosity as a function of gel concentration and time. They have also developed a model to calculate soil properties after complete solidification of the grout. The numerical model has been used to design and analyze laboratory experiments and field pilot tests. The authors present the results of computer simulations of grout injection, redistribution, and solidification

  16. Barrier island facies models and recognition criteria

    Science.gov (United States)

    Mulhern, J.; Johnson, C. L.

    2017-12-01

    Barrier island outcrops record transgressive shoreline motion at geologic timescales, providing integral clues to understanding how coastlines respond to rising sea levels. However, barrier island deposits are difficult to recognize. While significant progress has been made in understanding the modern coastal morphodynamics, this insight is not fully leveraged in existing barrier island facies models. Excellent outcrop exposures of the paralic Upper Cretaceous Straight Cliffs Formation of southern Utah provide an opportunity to revise facies models and recognition criteria for barrier island deposits. Preserved barrier islands are composed of three main architectural elements (shorefaces, tidal inlets, and tidal channels) which occur independently or in combination to create larger-scale barrier island deposits. Barrier island shorefaces record progradation, while barrier island tidal inlets record lateral migration, and barrier island tidal channels record aggradation within the tidal inlet. Four facies associations are used to describe and characterize these barrier island architectural elements. Barrier islands occur in association with backarrier fill and internally contain lower and upper shoreface, high-energy upper shoreface, and tidal channel facies. Barrier islands bound lagoons or estuaries, and are distinguished from other shoreface deposits by their internal facies and geometry, association with backbarrier facies, and position within transgressive successions. Tidal processes, in particular tidal inlet migration and reworking of the upper shoreface, also distinguish barrier island deposits. Existing barrier island models highlight the short term heterogeneous and dynamic nature of barrier island systems, yet overlook processes tied to geologic time scales, such as multi-directional motion, erosion, and reworking, and their expressions in preserved barrier island strata. This study uses characteristic outcrop expressions of barrier island successions to

  17. A meta-analysis of peripheral blood nerve growth factor levels in patients with schizophrenia.

    Science.gov (United States)

    Qin, X-Y; Wu, H-T; Cao, C; Loh, Y P; Cheng, Y

    2017-09-01

    Neurotrophins particularly brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are crucial modulators in the neurodevelopment and maintenance of central and peripheral nervous systems. Neurotrophin hypothesis of schizophrenia (SCZ) postulated that the changes in the brains of SCZ patients are the result of disturbances of developing processes involving neurotrophic factors. This hypothesis was mainly supported by the abnormal regulation of BDNF in SCZ, especially the decreased peripheral blood BDNF levels in SCZ patients validated by several meta-analyses. However, the regulation of NGF in SCZ remains unclear because of the inconsistent findings from the clinical studies. Therefore, we undertook, to the best of our knowledge, the first systematic review with a meta-analysis to quantitatively summarize the peripheral blood NGF data in SCZ patients compared with healthy control (HC) subjects. A systematic search of Pubmed, PsycINFO and Web of Science identified 13 articles encompassing a sample of 1693 individuals for the meta-analysis. Random-effects meta-analysis showed that patients with SCZ had significantly decreased peripheral blood levels of NGF when compared with the HC subjects (Hedges's g=-0.633, 95% confidence interval (CI)=-0.948 to -0.318, Pmeta-regression analyses showed that age, gender and sample size had no moderating effects on the outcome of the meta-analysis, whereas disease severity might be a confounding factor for the meta-analysis. These results demonstrated that patients with SCZ are accompanied by the decreased peripheral blood NGF levels, strengthening the clinical evidence of an abnormal neurotrophin profile in the patients with SCZ.

  18. Barriers to improvements in energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, A.K.N.

    1991-10-01

    To promote energy-efficiency improvements, actions may be required at one or more levels -- from the lowest level of the consumer (residential, commercial, industrial, etc.) through the highest level of the global agencies. But barriers to the implementation of energy-efficiency improvements exist or can arise at all these levels. Taking up each one of these barriers in turn, the paper discusses specific measures that can contribute to overcoming the barriers. However, a one-barrier-one-measure approach must be avoided. Single barriers may in fact involve several sub-barriers. Also, combinations of measures are much more effective in overcoming barriers. In particular, combinations of measures that simultaneously overcome several barriers are most successful. The paper discusses the typology of barriers, explores their origin and suggests measures that by themselves or in combination with other measures, will overcome these barriers. Since most of the barriers dealt with can be found in the barriers'' literature, any originality in the paper lies in its systematic organization, synoptic view and holistic treatment of this issue. This paper is intended to initiate a comprehensive treatment of barriers, their origins and the measures that contribute to overcoming them. Hopefully, such a treatment will facilitate the implementation of energy-efficiency improvements involving a wide diversity of ever-changing energy end uses and consumer preferences.

  19. Barriers to improvements in energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, A.K.N.

    1991-10-01

    To promote energy-efficiency improvements, actions may be required at one or more levels -- from the lowest level of the consumer (residential, commercial, industrial, etc.) through the highest level of the global agencies. But barriers to the implementation of energy-efficiency improvements exist or can arise at all these levels. Taking up each one of these barriers in turn, the paper discusses specific measures that can contribute to overcoming the barriers. However, a one-barrier-one-measure approach must be avoided. Single barriers may in fact involve several sub-barriers. Also, combinations of measures are much more effective in overcoming barriers. In particular, combinations of measures that simultaneously overcome several barriers are most successful. The paper discusses the typology of barriers, explores their origin and suggests measures that by themselves or in combination with other measures, will overcome these barriers. Since most of the barriers dealt with can be found in the ``barriers`` literature, any originality in the paper lies in its systematic organization, synoptic view and holistic treatment of this issue. This paper is intended to initiate a comprehensive treatment of barriers, their origins and the measures that contribute to overcoming them. Hopefully, such a treatment will facilitate the implementation of energy-efficiency improvements involving a wide diversity of ever-changing energy end uses and consumer preferences.

  20. Prototype Hanford Surface Barrier: Design basis document

    International Nuclear Information System (INIS)

    Myers, D.R.; Duranceau, D.A.

    1994-11-01

    The Hanford Site Surface Barrier Development Program (BDP) was organized in 1985 to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site and other arid sites. This document provides the basis of the prototype barrier. Engineers and scientists have momentarily frozen evolving barrier designs and incorporated the latest findings from BDP tasks. The design and construction of the prototype barrier has required that all of the various components of the barrier be brought together into an integrated system. This integration is particularly important because some of the components of the protective barreir have been developed independently of other barreir components. This document serves as the baseline by which future modifications or other barrier designs can be compared. Also, this document contains the minutes of meeting convened during the definitive design process in which critical decisions affecting the prototype barrier's design were made and the construction drawings

  1. Highway renewable energy : photovoltaic noise barriers

    Science.gov (United States)

    2017-07-01

    Highway photovoltaic noise barriers (PVNBs) represent the combination of noise barrier systems and photovoltaic systems in order to mitigate traffic noise while simultaneously producing renewable energy. First deployed in Switzerland in 1989, PVNBs a...

  2. Physical Environmental Barriers to School Attendance among ...

    African Journals Online (AJOL)

    environment were the major barriers to school attendance. Conclusion: To ... Key words: Parents/caregivers, children with disabilities, barriers. Introduction .... It is not safe to walk ... feeling, learning, behaviour, and fits or convulsions. [19] The ...

  3. Security barriers with automated reconnaissance

    Science.gov (United States)

    McLaughlin, James O; Baird, Adam D; Tullis, Barclay J; Nolte, Roger Allen

    2015-04-07

    An intrusion delaying barrier includes primary and secondary physical structures and can be instrumented with multiple sensors incorporated into an electronic monitoring and alarm system. Such an instrumented intrusion delaying barrier may be used as a perimeter intrusion defense and assessment system (PIDAS). Problems with not providing effective delay to breaches by intentional intruders and/or terrorists who would otherwise evade detection are solved by attaching the secondary structures to the primary structure, and attaching at least some of the sensors to the secondary structures. By having multiple sensors of various types physically interconnected serves to enable sensors on different parts of the overall structure to respond to common disturbances and thereby provide effective corroboration that a disturbance is not merely a nuisance or false alarm. Use of a machine learning network such as a neural network exploits such corroboration.

  4. Application of polycrystalline diffusion barriers

    International Nuclear Information System (INIS)

    Tsymbal, V.A.; Kolupaev, I.N.

    2010-01-01

    Degradation of contacts of the electronic equipment at the raised temperatures is connected with active diffusion redistribution of components contact - metalized systems (CMS) and phase production on interphase borders. One of systems diffusion barriers (DB) are polycrystalline silicide a film, in particular silicides of the titan. Reception disilicide the titan (TiSi 2 ) which on the parameters is demanded for conditions of microelectronics from known silicides of system Ti-Si, is possible as a result of direct reaction of a film of the titan and a substrate of silicon, and at sedimentation of layer Ti-Si demanded stoichiometric structure. Simultaneously there is specific problem polycrystalline diffusion a barrier (PDB): the polycrystalline provides structural balance and metastability film disilicide, but leaves in it borders of grains - easy local ways of diffusion. In clause the analysis diffusion permeability polycrystalline and polyphase DB is made and recommendations for practical methods of increase of blocking properties PDB are made.

  5. Sea sand for reactive barriers

    International Nuclear Information System (INIS)

    Garcia R, G.; Ordonez R, E.; Ordonez R, En.

    2002-01-01

    Some phosphates have the property to suck in radioactive metals in solution, what it is taken in advance to make reactive barriers which are placed in the nuclear waste repositories. In an effort for contributing to the study of this type of materials, it has been obtained the zirconium silicate (ZrSiO 4 ) and the alpha zirconium hydrogen phosphate (Zr(HPO 4 ) 2H 2 O) starting from sea sand in an easy and economic way. (Author)

  6. Fission barriers of light nuclei

    International Nuclear Information System (INIS)

    Grotowski, K.; Planeta, R.; Blann, M.; Komoto, T.

    1989-01-01

    Experimental fission excitation functions for compound nuclei /sup 52/Fe, /sup 49/Cr, /sup 46/V, and /sup 44/Ti formed in heavy-ion reactions are analyzed in the Hauser-Feshbach/Bohr-Wheeler formalism using fission barriers based on the rotating liquid drop model of Cohen et al. and on the rotating finite range model of Sierk. We conclude that the rotating finite range approach gives better reproduction of experimental fission yields, consistent with results found for heavier systems

  7. Zirconium-barrier cladding attributes

    International Nuclear Information System (INIS)

    Rosenbaum, H.S.; Rand, R.A.; Tucker, R.P.; Cheng, B.; Adamson, R.B.; Davies, J.H.; Armijo, J.S.; Wisner, S.B.

    1987-01-01

    This metallurgical study of Zr-barrier fuel cladding evaluates the importance of three salient attributes: (1) metallurgical bond between the zirconium liner and the Zircaloy substrate, (2) liner thickness (roughly 10% of the total cladding wall), and (3) softness (purity). The effect that each of these attributes has on the pellet-cladding interaction (PCI) resistance of the Zr-barrier fuel was studied by a combination of analytical model calculations and laboratory experiments using an expanding mandrel technique. Each of the attributes is shown to contribute to PCI resistance. The effect of the zirconium liner on fuel behavior during off-normal events in which steam comes in contact with the zirconium surface was studied experimentally. Simulations of loss-of-coolant accident (LOCA) showed that the behavior of Zr-barrier cladding is virtually indistinguishable from that of conventional Zircaloy cladding. If steam contacts the zirconium liner surface through a cladding perforation and the fuel rod is operated under normal power conditions, the zirconium liner is oxidized more rapidly than is Zircaloy, but the oxidation rate returns to the rate of Zircaloy oxidation when the oxide phase reaches the zirconium-Zircaloy metallurgical bond

  8. Filamentary and diffuse barrier discharges

    International Nuclear Information System (INIS)

    Kogelschatz, U.

    2001-01-01

    Barrier discharges, sometimes also referred to as dielectric-barrier discharges or silent discharges, are characterized by the presence of at least one insulating layer in contact with the discharge between two planar or cylindrical electrodes connected to an ac power supply. The main advantage of this type of electrical discharge is, that non-equilibrium plasma conditions in atmospheric-pressure gases can be established in an economic and reliable way. This has led to a number of important applications including industrial ozone generation, surface modification of polymers, plasma chemical vapor deposition, excitation of CO 2 lasers, excimer lamps and, most recently, large-area flat plasma display panels. Depending on the application, the width of the discharge gap can range from less than 0.1 mm to about 100 mm and the applied frequency from below line frequency to several gigahertz. Typical materials used for the insulating layer (dielectric barrier) are glass, quartz, ceramics but also thin enamel or polymer layers

  9. Perceptions regarding strategic and structural entry barriers

    NARCIS (Netherlands)

    Lutz, C.H.M.; Kemp, R.G.M.; Dijkstra, S.G.

    2010-01-01

    This article uses factor analysis to identify the underlying dimensions of strategic and structural entry barriers. We find that, in the perception of firms, both types of barriers are important and that the effectiveness of strategic barriers depends on attributes of the market structure. Based on

  10. Perceptions regarding strategic and structural entry barriers

    NARCIS (Netherlands)

    Lutz, Clemens H. M.; Kemp, Ron G. M.; Dijkstra, S. Gerhard

    This article uses factor analysis to identify the underlying dimensions of strategic and structural entry barriers. We find that, in the perception of firms, both types of barriers are important and that the effectiveness of strategic barriers depends on attributes of the market structure. Based on

  11. Faculty Perceptions about Barriers to Active Learning

    Science.gov (United States)

    Michael, Joel

    2007-01-01

    Faculty may perceive many barriers to active learning in their classrooms. Four groups of participants in a faculty development workshop were asked to list their perceived barriers to active learning. Many of the problems identified were present on more than one list. The barriers fall into three categories: student characteristics, issues…

  12. Barriers to Mammography among Inadequately Screened Women

    Science.gov (United States)

    Stoll, Carolyn R. T.; Roberts, Summer; Cheng, Meng-Ru; Crayton, Eloise V.; Jackson, Sherrill; Politi, Mary C.

    2015-01-01

    Mammography use has increased over the past 20 years, yet more than 30% of women remain inadequately screened. Structural barriers can deter individuals from screening, however, cognitive, emotional, and communication barriers may also prevent mammography use. This study sought to identify the impact of number and type of barriers on mammography…

  13. Market barriers to welfare product innovations

    NARCIS (Netherlands)

    Binnekamp, M.H.A.; Ingenbleek, P.T.M.

    2006-01-01

    New products that are based on higher animal welfare standards encounter several barriers on the road to market acceptance. The authors focus on the Dutch poultry sector and distinguish between retailer and consumer barriers. Retailer barriers include the powerful position of retailers, the price

  14. Article Including Environmental Barrier Coating System

    Science.gov (United States)

    Lee, Kang N. (Inventor)

    2015-01-01

    An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.

  15. Converse Theorems for Safety and Barrier Certificates

    OpenAIRE

    Ratschan, Stefan

    2017-01-01

    An important tool for proving safety of dynamical systems is the notion of a barrier certificate. In this paper we prove that every robustly safe ordinary differential equation has a barrier certificate. Moreover, we show a construction of such a barrier certificate based on a set of states that is reachable in finite time.

  16. Cryogenic Barrier Demonstration Project. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, L.A.; Yarmak, E.; Long, E.L.

    2000-03-01

    A long-term frozen soil barrier was implemented at the HRE (Homogeneous Reactor Experiment) Pond facility at the Oak Ridge National Laboratory in 1997. This was performed to verify the technical feasibility and costs of deploying a frozen barrier at a radiologically contaminated site. Work began in September 1996 and progressed through to December 1999. The frozen barrier has been operational since November 1997. Verification of the barrier integrity was performed independently by the EPA's SITE Program. This project showed frozen barriers offer a proven technology to retain below grade hazardous substances at relatively low costs with minimal effect on the environment.

  17. Chemical barriers for controlling groundwater contamination

    International Nuclear Information System (INIS)

    Morrison, S.J.; Spangler, R.R.

    1993-01-01

    Chemical barriers are being explored as a low-cost means of controlling groundwater contamination. The barrier can intercept a contaminant plume and prevent migration by transferring contaminants from the groundwater to immobile solids. A chemical barrier can be emplaced in a landfill liner or in an aquifer cutoff wall or can be injected into a contaminant plume. Chemical barriers can be classified as either precipitation barriers or sorption barriers depending upon the dominant mode of contaminant extraction. In a precipitation barrier, contaminants are bound in the structures of newly formed phases; whereas, in a sorption barrier, contaminants attach to the surfaces of preexisting solids by adsorption or some other surface mechanism. Sorption of contaminants is pH dependent. A precipitation barrier can control the pH of the system, but alkaline groundwater may dominate the pH in a sorption barrier. A comparison is made of the characteristics of precipitation and sorption barriers. Experimental data on the extraction of uranium and molybdenum from simulated groundwater are used to demonstrate these concepts. 10 refs., 9 figs., 1 tab

  18. Schizophrenia: breaking down the barriers.

    Science.gov (United States)

    Haghighat, R

    1997-01-01

    This paper reviews the key issues presented during the Fourth International Conference on Schizophrenia, which was held in October 1996 in Vancouver, Canada. The main emphasis was placed on the problem of stigma, loneliness and work as well as on the necessity to further elucidate the physiopathology of schizophrenia. Some of the barriers discussed are unlikely to disappear from human societies in the short term with any possible cure for schizophrenia as they are part of any major long-term illness, of which there is a long and ever increasing list.

  19. Fission barriers of superheavy nuclei

    International Nuclear Information System (INIS)

    Burvenich, T.

    2001-01-01

    Full text: Self consistent microscopic mean-field models are powerful tools for the description of nuclear structure phenomena in the region of known elements, where they have reached a good quality. Especially the Skyrme-Hartree-Fock (SHF) method and the Relativistic Mean-Field (RMF) model will be considered in the discussion of the properties of these models. When it comes to extrapolation to the region of superheavy elements, though there is agreement concerning the global trends, these model exhibit significant differences in their predictions concerning fission barrier heights and structures. (Author)

  20. Double barrier system for an in situ conversion process

    Science.gov (United States)

    McKinzie, Billy John [Houston, TX; Vinegar, Harold J [Bellaire, TX; Cowan, Kenneth Michael [Sugar land, TX; Deeg, Wolfgang Friedrich Johann [Houston, TX; Wong, Sau-Wai [Rijswijk, NL

    2009-05-05

    A barrier system for a subsurface treatment area is described. The barrier system includes a first barrier formed around at least a portion of the subsurface treatment area. The first barrier is configured to inhibit fluid from exiting or entering the subsurface treatment area. A second barrier is formed around at least a portion of the first barrier. A separation space exists between the first barrier and the second barrier.

  1. Mediated Intercultural Communication Barrier in No Drama Zone! Group

    OpenAIRE

    Lizal, Valentino

    2015-01-01

    This research study aimed to describe the mediated intercultural communication barriers in the No Drama Zone! group. This study is a qualitative descriptive type of research, with case study method. By doing in depth interview and observation, researcher found two barriers that generates other barriers in the group's mediated intercultural communication. The two big barriers were: language and physical barriers. Language barriers in this group generated two barriers, emotional barrier and pe...

  2. Subsurface barrier verification technologies, informal report

    International Nuclear Information System (INIS)

    Heiser, J.H.

    1994-06-01

    One of the more promising remediation options available to the DOE waste management community is subsurface barriers. Some of the uses of subsurface barriers include surrounding and/or containing buried waste, as secondary confinement of underground storage tanks, to direct or contain subsurface contaminant plumes and to restrict remediation methods, such as vacuum extraction, to a limited area. To be most effective the barriers should be continuous and depending on use, have few or no breaches. A breach may be formed through numerous pathways including: discontinuous grout application, from joints between panels and from cracking due to grout curing or wet-dry cycling. The ability to verify barrier integrity is valuable to the DOE, EPA, and commercial sector and will be required to gain full public acceptance of subsurface barriers as either primary or secondary confinement at waste sites. It is recognized that no suitable method exists for the verification of an emplaced barrier's integrity. The large size and deep placement of subsurface barriers makes detection of leaks challenging. This becomes magnified if the permissible leakage from the site is low. Detection of small cracks (fractions of an inch) at depths of 100 feet or more has not been possible using existing surface geophysical techniques. Compounding the problem of locating flaws in a barrier is the fact that no placement technology can guarantee the completeness or integrity of the emplaced barrier. This report summarizes several commonly used or promising technologies that have been or may be applied to in-situ barrier continuity verification

  3. Overcoming Barriers in Unhealthy Settings

    Directory of Open Access Journals (Sweden)

    Michael K. Lemke

    2016-03-01

    Full Text Available We investigated the phenomenon of sustained health-supportive behaviors among long-haul commercial truck drivers, who belong to an occupational segment with extreme health disparities. With a focus on setting-level factors, this study sought to discover ways in which individuals exhibit resiliency while immersed in endemically obesogenic environments, as well as understand setting-level barriers to engaging in health-supportive behaviors. Using a transcendental phenomenological research design, 12 long-haul truck drivers who met screening criteria were selected using purposeful maximum sampling. Seven broad themes were identified: access to health resources, barriers to health behaviors, recommended alternative settings, constituents of health behavior, motivation for health behaviors, attitude toward health behaviors, and trucking culture. We suggest applying ecological theories of health behavior and settings approaches to improve driver health. We also propose the Integrative and Dynamic Healthy Commercial Driving (IDHCD paradigm, grounded in complexity science, as a new theoretical framework for improving driver health outcomes.

  4. Barriers to medical error reporting

    Directory of Open Access Journals (Sweden)

    Jalal Poorolajal

    2015-01-01

    Full Text Available Background: This study was conducted to explore the prevalence of medical error underreporting and associated barriers. Methods: This cross-sectional study was performed from September to December 2012. Five hospitals, affiliated with Hamadan University of Medical Sciences, in Hamedan,Iran were investigated. A self-administered questionnaire was used for data collection. Participants consisted of physicians, nurses, midwives, residents, interns, and staffs of radiology and laboratory departments. Results: Overall, 50.26% of subjects had committed but not reported medical errors. The main reasons mentioned for underreporting were lack of effective medical error reporting system (60.0%, lack of proper reporting form (51.8%, lack of peer supporting a person who has committed an error (56.0%, and lack of personal attention to the importance of medical errors (62.9%. The rate of committing medical errors was higher in men (71.4%, age of 50-40 years (67.6%, less-experienced personnel (58.7%, educational level of MSc (87.5%, and staff of radiology department (88.9%. Conclusions: This study outlined the main barriers to reporting medical errors and associated factors that may be helpful for healthcare organizations in improving medical error reporting as an essential component for patient safety enhancement.

  5. Richards Barrier LA Reference Design Feature Evaluation

    International Nuclear Information System (INIS)

    N.E. Kramer

    1999-01-01

    The Richards Barrier is one of the design features of the repository to be considered for the License Application (LA), Richards was a soil scientist who first described the diversion of moisture between two materials with different hydrologic properties. In this report, a Richards Barrier is a special type of backfill with a fine-grained material (such as sand) overlaying a coarse-grained material (such as gravel). Water that enters an emplacement drift will first encounter the fine-grained material and be transported around the coarse-grained material covering the waste package, thus protecting the waste package from contact with most of the groundwater. The objective of this report is to discuss the benefits and liabilities to the repository by the inclusion of a Richards Barrier type backfill in emplacement drifts. The Richards Barrier can act as a barrier to water flow, can reduce the waste package material dissolution rate, limit mobilization of the radionuclides, and can provide structural protection for the waste package. The scope of this report is to: (1) Analyze the behavior of barrier materials following the intrusion of groundwater for influxes of 1 to 300 mm per year. The report will demonstrate diversion of groundwater intrusions into the barrier over an extended time period when seismic activity and consolidation may cause the potential for liquefaction and settlement of the Richards Barrier. (2) Review the thermal effects of the Richards Barrier on material behavior. (3) Analyze the effect of rockfall on the performance of the Richards Barrier and the depth of the barrier required to protect waste packages under the barrier. (4) Review radiological and heating conditions on placement of multiple layers of the barrier. Subsurface Nuclear Safety personnel will perform calculations to determine the radiation reduction-time relationship and shielding capacity of the barrier. (5) Evaluate the effects of ventilation on cooling of emplacement drifts and

  6. Measuring solvent barrier properties of paper

    International Nuclear Information System (INIS)

    Bollström, Roger; Saarinen, Jarkko J; Toivakka, Martti; Räty, Jukka

    2012-01-01

    New methods for measuring barrier properties against solvents, acids and bases on dispersion coated paper were developed and investigated. Usability, reliability and repeatability were compared both between the new methods and with the standardized method for measuring barrier properties against water vapor. Barrier properties could be measured with all methods and the results obtained by the different methods were in correlation with each other. A qualitative method based on a trace color provided an indicative result, whereas further developed methods also took into account the durability. The effective barrier lifetime could be measured by measuring the conductivity through the substrate as a function of time, or by utilizing a glass prism where the change in refractive index caused by penetrated liquid was monitored, also as a function of time. Barrier properties against water and humidity were also measured and were found not to be predictors for barrier properties against either solvents, or acids or bases, which supports the need to develop new methods

  7. Barrier experiment: Shock initiation under complex loading

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-12

    The barrier experiments are a variant of the gap test; a detonation wave in a donor HE impacts a barrier and drives a shock wave into an acceptor HE. The question we ask is: What is the trade-off between the barrier material and threshold barrier thickness to prevent the acceptor from detonating. This can be viewed from the perspective of shock initiation of the acceptor subject to a complex pressure drive condition. Here we consider key factors which affect whether or not the acceptor undergoes a shock-to-detonation transition. These include the following: shock impedance matches for the donor detonation wave into the barrier and then the barrier shock into the acceptor, the pressure gradient behind the donor detonation wave, and the curvature of detonation front in the donor. Numerical simulations are used to illustrate how these factors affect the reaction in the acceptor.

  8. Breaking the Barriers to the Circular Economy

    OpenAIRE

    Kirchherr, J.W.; Hekkert, M.P.; Bour, Ruben; Huijbrechtse-Truijens, Anne; Kostense-Smit, Erica; Muller, Jennifer

    2017-01-01

    The Copernicus Institute of Sustainable Development, Utrecht University, the Netherlands and Deloitte have jointly carried out research on barriers to the Circular Economy (CE) in the European Union. For this research, a survey with 153 businesses, 55 government officials and expert interviews with forty-seven thought leaders on the circular economy from businesses, governments, academia and NGOs have been carried out. Two types of barriers emerged as main barriers Firstly, there are the cult...

  9. Barriers for realisation of energy savings in buildings; Barrierer for realisering af energibesparelser i bygninger

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, O.M.

    2004-07-01

    Many years' efforts within the energy labelling area have shown large saving potentials in heating and use of electricity in buildings. At the same time it has been proved that these saving potentials, even when economically advantageous, only are cashed to a limited extent. The reason to this is ascribed to barriers that meet the individual building owner who wants to start saving energy. Most barriers are known and a lot of these have been sought overcome for some time. The questions are how many barriers still exist, have new barriers arisen and the character of these barriers. On this background the objective of this survey has been to concretize and study the barriers, which are blocking reasonable energy savings. Focus has especially been on barriers for realisation of heating savings, but through a general evaluation of energy savings of barriers other forms of energy saving methods have been taken into consideration. Special interest has been directed towards houses, typically one family houses, which are affected by the Energy Labelling Scheme. The concept barriers include all kinds of barriers, also barriers that not are acknowledged as barriers by the individual house owner, or that on closer inspection turn out to be something else than actual barriers. This note suggests an alternative inertia model, in order to create an idea of the inertness characteristic of the many house owners who understand the message but fail to act on it. (BA)

  10. High Performance Multi Barrier Thermionic Devices

    National Research Council Canada - National Science Library

    Vashaee, Daryoosh; Shakouri, Ali

    2003-01-01

    Thermoelectric transport perpendicular to layers in multiple barrier superlattice structures is investigated theoretically in two limiting cases of no lateral momentum scattering and strong scattering...

  11. Water and contaminant movement: migration barriers

    International Nuclear Information System (INIS)

    Lane, L.J.; Nyhan, J.W.

    1984-11-01

    Migration barriers are used in shallow land burial facilities to slow or stop the movement of water and contaminants and are discussed here as a single component embedded in a complex environmental system. Analytical solutions to solute transport equations are used to approximate the behavior of migration barriers and to derive design criteria for control of subsurface water and contaminant migration. Various types of migration barriers are compared and design recommendations are made for shallow land burial trench caps and liners. Needed improvements and suggested field experiments for future designs of migration barriers are then discussed relative to the management of low-level radioactive wastes

  12. Barriers Approach to Innovation in Academic Libraries

    Directory of Open Access Journals (Sweden)

    Fu-Hsuan Chuang

    2016-11-01

    Full Text Available Innovation in academic libraries is not a brand new issue. Academic libraries can benefit from successful innovation, since innovation is a key contributor to gaining and sustaining competitive advantage for survival. Building on two case studies, 28 participants from leadership teams to practitioners are involved, the qualitative findings identified the specific two types of barriers that academic libraries face by applying a barriers approach to innovation, that’s, environmental and organizational barriers. Especially, seven dimensions of two types of barriers to innovation are found.

  13. Barriers to healthcare for transgender individuals.

    Science.gov (United States)

    Safer, Joshua D; Coleman, Eli; Feldman, Jamie; Garofalo, Robert; Hembree, Wylie; Radix, Asa; Sevelius, Jae

    2016-04-01

    Transgender persons suffer significant health disparities and may require medical intervention as part of their care. The purpose of this manuscript is to briefly review the literature characterizing barriers to healthcare for transgender individuals and to propose research priorities to understand mechanisms of those barriers and interventions to overcome them. Current research emphasizes sexual minorities' self-report of barriers, rather than using direct methods. The biggest barrier to healthcare reported by transgender individuals is lack of access because of lack of providers who are sufficiently knowledgeable on the topic. Other barriers include: financial barriers, discrimination, lack of cultural competence by providers, health systems barriers, and socioeconomic barriers. National research priorities should include rigorous determination of the capacity of the US healthcare system to provide adequate care for transgender individuals. Studies should determine knowledge and biases of the medical workforce across the spectrum of medical training with regard to transgender medical care; adequacy of sufficient providers for the care required, larger social structural barriers, and status of a framework to pay for appropriate care. As well, studies should propose and validate potential solutions to address identified gaps.

  14. Antimicrobial Peptides, Infections and the Skin Barrier

    DEFF Research Database (Denmark)

    Clausen, Maja Lisa; Agner, Tove

    2016-01-01

    The skin serves as a strong barrier protecting us from invading pathogens and harmful organisms. An important part of this barrier comes from antimicrobial peptides (AMPs), which are small peptides expressed abundantly in the skin. AMPs are produced in the deeper layers of the epidermis and trans......The skin serves as a strong barrier protecting us from invading pathogens and harmful organisms. An important part of this barrier comes from antimicrobial peptides (AMPs), which are small peptides expressed abundantly in the skin. AMPs are produced in the deeper layers of the epidermis...

  15. Radon barrier: Method of testing airtightness

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn; Buch-Hansen, Thomas Cornelius

    2017-01-01

    The test method NBI 167/02 Radon membrane: Test of airtightness can be used for determining the airtightness of a radon barrier as a system solution. The test determines the air infiltration through the radon barrier for a number of levels of air pressure differences. The airflow through versus...... of the barrier with the low air pressure, through a well-defined opening, as a modification of the test method in general. Results, obtained using the improved test method, are shown for a number of radon barriers tested....

  16. Religious culture as a barrier?

    DEFF Research Database (Denmark)

    Agergaard, Sine

    2016-01-01

    Political interventions, media coverage and research often refer to the underrepresentation of ethnic minorities, particularly girls and women, participating in physical activity and organised sports. In both public and academic debates, reference is made to the religious culture as a particular...... barrier to participation in sports among Muslim girls and women. This article aims to provide a counter-narrative by focusing on young Muslim girls who simultaneously practice their religion and sports. The main research question was: How do young Danish Muslim girls align participation in sports...... religion as hegemonic, embodied and dynamic cultural phenomena, the analysis points to the diversity through which Muslim girls and women participate and engage in sports. Finally, the article discusses the extent to which counter-narratives may contribute to changing perspectives on so-called hard...

  17. Modeling of Thermal Barrier Coatings

    Science.gov (United States)

    Ferguson, B. L.; Petrus, G. J.; Krauss, T. M.

    1992-01-01

    The project examined the effectiveness of studying the creep behavior of thermal barrier coating system through the use of a general purpose, large strain finite element program, NIKE2D. Constitutive models implemented in this code were applied to simulate thermal-elastic and creep behavior. Four separate ceramic-bond coat interface geometries were examined in combination with a variety of constitutive models and material properties. The reason for focusing attention on the ceramic-bond coat interface is that prior studies have shown that cracking occurs in the ceramic near interface features which act as stress concentration points. The model conditions examined include: (1) two bond coat coefficient of thermal expansion curves; (2) the creep coefficient and creep exponent of the bond coat for steady state creep; (3) the interface geometry; and (4) the material model employed to represent the bond coat, ceramic, and superalloy base.

  18. Permeability Barrier Generation in the Martian Lithosphere

    Science.gov (United States)

    Schools, Joe; Montési, Laurent

    2015-11-01

    Permeability barriers develop when a magma produced in the interior of a planet rises into the cooler lithosphere and crystallizes more rapidly than the lithosphere can deform (Sparks and Parmentier, 1991). Crystallization products may then clog the porous network in which melt is propagating, reducing the permeability to almost zero, i.e., forming a permeability barrier. Subsequent melts cannot cross the barrier. Permeability barriers have been useful to explain variations in crustal thickness at mid-ocean ridges on Earth (Magde et al., 1997; Hebert and Montési, 2011; Montési et al., 2011). We explore here under what conditions permeability barriers may form on Mars.We use the MELTS thermodynamic calculator (Ghiorso and Sack, 1995; Ghiorso et al., 2002; Asimow et al., 2004) in conjunction with estimated Martian mantle compositions (Morgan and Anders, 1979; Wänke and Dreibus, 1994; Lodders and Fegley, 1997; Sanloup et al., 1999; Taylor 2013) to model the formation of permeability barriers in the lithosphere of Mars. In order to represent potential past and present conditions of Mars, we vary the lithospheric thickness, mantle potential temperature (heat flux), oxygen fugacity, and water content.Our results show that permeability layers can develop in the thermal boundary layer of the simulated Martian lithosphere if the mantle potential temperature is higher than ~1500°C. The various Martian mantle compositions yield barriers in the same locations, under matching variable conditions. There is no significant difference in barrier location over the range of accepted Martian oxygen fugacity values. Water content is the most significant influence on barrier development as it reduces the temperature of crystallization, allowing melt to rise further into the lithosphere. Our lower temperature and thicker lithosphere model runs, which are likely the most similar to modern Mars, show no permeability barrier generation. Losing the possibility of having a permeability

  19. Identifying barriers to emergency care services.

    Science.gov (United States)

    Cannoodt, Luk; Mock, Charles; Bucagu, Maurice

    2012-01-01

    This paper aims to present a review of published evidence of barriers to emergency care, with attention towards both financial and other barriers. With the keywords (financial) accessibility, barriers and emergency care services, citations in PubMed were searched and further selected in the context of the objective of this article. Forty articles, published over a period of 15 years, showed evidence of significant barriers to emergency care. These barriers often tend to persist, despite the fact that the evidence was published many years ago. Several publications stressed the importance of the financial barriers in foregoing or delaying potentially life-saving emergency services, both in poor and rich countries. Other publications report non-financial barriers that prevent patients in need of emergency care (pre-hospital and in-patient care) from seeking care, from arriving in the proper emergency department without undue delay or from receiving proper treatment when they do arrive in these departments. It is clear that timely access to life-saving and disability-preventing emergency care is problematic in many settings. Yet, low-cost measures can likely be taken to significantly reduce these barriers. It is time to make an inventory of these measures and to implement the most cost-effective ones worldwide. Copyright © 2011 John Wiley & Sons, Ltd.

  20. Contaminant containment using polymer gel barriers

    NARCIS (Netherlands)

    Darwish, M.I.M.; Rowe, R.K.; Maarel, van der J.R.C.; Pel, L.; Huinink, H.P.; Zitha, P.L.J.

    2004-01-01

    Polymer gels are well known in the oil industry, but their potential for use as barriers to contaminant transport has not previously received significant study. As a first step, this paper examines the potential for a polyelectrolyte gel to serve as a barrier to the migration of sodium chloride. Two

  1. Storm impacts on small barrier islands

    DEFF Research Database (Denmark)

    Kroon, Aart; Fruergaard, Mikkel

    The shorelines of the Baltic Sea and the inner coastal waters in Denmark consist of many barrier islands. These sandy barrier islands were mainly formed in the Holocene and are still very dynamic. The present day changes in the morphology are dominantly governed by storm waves and associated high...

  2. Engineered Barrier Test Facility status report, 1984

    International Nuclear Information System (INIS)

    Phillips, S.J.; Adams, M.R.; Gilbert, T.W.; Meinhardt, C.C.; Mitchell, R.M.; Waugh, W.J.

    1985-02-01

    This report provides a general summary of activities completed to date at the Hanford Engineered Barrier Test Facility. This facility is used to test and compare construction practices and performance of alternative designs of engineered barrier cover systems. These cover systems are being evaluated for potential use for isolation and confinement of buried waste disposal structures

  3. Nurses' barriers to learning: an integrative review.

    Science.gov (United States)

    Santos, Marion C

    2012-07-01

    This integrative review of the literature describes nurses' barriers to learning. Five major themes emerged: time constraints, financial constraints, workplace culture, access/relevance, and competency in accessing electronic evidence-based practice literature. The nurse educator must address these barriers for the staff to achieve learning and competency.

  4. Barriers to Adult Learning: Bridging the Gap

    Science.gov (United States)

    Falasca, Marina

    2011-01-01

    A fundamental aspect of adult education is engaging adults in becoming lifelong learners. More often than not, this requires removing barriers to learning, especially those relating to the actual organisational or institutional learning process. This article explores some of the main barriers to adult learning discussed in the literature and…

  5. Barriers to adherence in cystic fibrosis

    DEFF Research Database (Denmark)

    Bregnballe, Vibeke; Schiøtz, Peter Oluf

    2012-01-01

    Danish patients with cystic fibrosis aged 14 to 25 years and their parents. Conclusions: The present study showed that the majority of adolescents with CF and their parents experienced barriers to treatment adherence. Patients and parents agreed that the three most common barriers encountered lack...

  6. Barrier Engineered Quantum Dot Infrared Photodetectors

    Science.gov (United States)

    2015-06-01

    251108. 6. Barve, Ajit V., Saumya Sengupta, Jun Oh Kim, John Montoya , Brianna Klein, Mohammad Ali Shirazi, Marziyeh Zamiri et al., "Barrier selection... H . Kim, Z-B. Tian, and Sanjay Krishna. "Barrier Engineered Infrared Photodetectors Based on Type-II InAs/GaSb Strained Layer Superlattices." (2013

  7. Photovoltaic noise barriers; Stille um die Laermschutzwand

    Energy Technology Data Exchange (ETDEWEB)

    Roepcke, I.

    2007-11-30

    Photovoltaic noise barriers are uncommon. There were some demonstration project, but interest died down - in spite of the fact that the EEG specifies the same level of reimbursement for PV noise barriers as for PlV roofs. Recently, efforts have been made to revive the market. (orig.)

  8. K-Basin isolation barrier seal

    International Nuclear Information System (INIS)

    Ruff, E.S.

    1994-10-01

    This report documents various aspects of the design, analysis, procurement, and fabrication of the hydraulic seal on the isolation barriers to be installed in the 100-K Area spent nuclear fuel basin. The isolation barrier is used to keep water in the basin in the event of an earthquake

  9. Israel's Security Barrier: Effects On Operational Factors

    National Research Council Canada - National Science Library

    2004-01-01

    .... The route of the barrier is tinder intense discussion at this time and if implemented as planned by the Sharon government will negatively affect the factors of space and force. The barrier must be constructed along the correct route in order to maximize operational factors.

  10. Fusion barriers in heavy ion collisions

    International Nuclear Information System (INIS)

    Zhu Long; Su Jun; Xie Wenjie; Guo Chenchen; Zhang Donghong; Zhang Fengshou

    2014-01-01

    Study of fusion barrier is very important for people to better understand fusion reactions. In this paper the Improved Isospin-dependent Quantum Molecular Dynamics (ImIQMD) model is introduced firstly. Then the shell correction effects, energy dependence, isospin effects and orientation effects of fusion barrier are studied. The fusion barriers for the fusion reactions "4"0Ca + "4"0Ca, "4"8Ca + "2"0"8Pb, "4"8Ca + "2"0"4Pb and "1"6O + "1"5"4Sm are extracted. The negative shell correction energies lower potential barriers of a certain reaction. A complex phenomenon of energy dependence is observed. It is also found that incident energy dependence of the barrier radius and barrier height shows opposite behaviors. The Coulomb potential shows weak energy dependence when distance of two colliding nuclei is lower than the touching distance. The isospin effects of the potential barrier are investigated. The orientation effects of the potential barrier are also discussed for the system "1"6O + "1"5"4Sm. (authors)

  11. Overcoming Barriers in Working with Families

    Science.gov (United States)

    Heru, Alison M.; Drury, Laura

    2006-01-01

    Objective: The Accreditation Council for Graduate Medical Education and the Residency Review Committee for psychiatry outline the expected competencies for residents. These competencies include working with families. This article describes barriers that residents face when working with families, and offers ways to overcome these barriers. Method:…

  12. Barriers to investment in emerging power markets

    Energy Technology Data Exchange (ETDEWEB)

    Beardsworth, Jr, J J [Hunton and Williams, Richmond, VA (United States)

    1994-12-31

    Investing in private power projects in developing countries is a very different issue from investment in the US or the UK. There are many investment barriers not present in developed nations. Firstly investment barriers need to be identified. Trouble may be encountered with legal authorization; the regulatory framework; government guarantees; fuel supply security; lender protection; labour laws and local commercial restrictions such as profits repatriation, currency convertibility, and taxes. Political barriers may also be encountered in the form of: government commitments and support; funding sources; political unrest; religion; and relationships with other countries. Investment barriers may be minimised by persuading the government to remove any legal barriers; the contract has then to be agreed. Factors in a successful contract include: power purchase agreements; fuel agreements; and implementation agreements. It is vital to have a source of information on local rules and customs, by working with local companies and employing local attorneys.

  13. Barriers to physical activity among working mothers.

    Science.gov (United States)

    Dombrowski, Jill J

    2011-04-01

    Working mothers experience several barriers to physical activity. If these barriers can be identified by occupational health nurses and they can partner with working mothers to reduce these perceived barriers, the health of these workers can be improved and chronic disease risk prevented. The purpose of this study was to measure the effect of self-regulatory efficacy on physical activity among working mothers and to describe specific barriers to physical activity. The Barriers Specific Self-Efficacy Scale (BARSE) and the Kaiser Physical Activity Survey (KPAS) were used to measure the variables. Self-regulatory efficacy was found to be a strong predictor of physical activity in a diverse sample of working mothers who did not meet current recommendations for physical activity. Occupational health nurses can use these findings to design programs for groups and for counseling individuals. Copyright 2011, SLACK Incorporated.

  14. Engineering kinetic barriers in copper metallization

    International Nuclear Information System (INIS)

    Huang Hanchen; Wei, H.L.; Woo, C.H.; Zhang, X.X.

    2002-01-01

    In metallization processes of integrated circuits, it is desirable to deposit the metal lines (aluminum or copper) fast and at low temperatures. However, the lines (films) usually consist of undesirable columns and voids, because of the absence of sufficient diffusion--a direct result of large kinetic barriers. Following the proposal and realization of the three-dimensional Ehrlich-Schwoebel (3D ES) barrier, we present here a method to engineer this kinetic barrier so as to improve quality of deposited copper films. We deposit copper films by magnetron sputtering, characterize the film structure and texture by using the scanning electron microscope and the x-ray diffraction, respectively. Taking indium as surfactant during copper deposition, we have achieved much better density and bottom coverage of copper filled trenches. The characterizations show that the improvement is the result of the 3D ES barrier reduction caused by indium addition. Engineering the 3D ES barrier therefore leads to improved film quality

  15. Barrier bucket experiment at the AGS

    Directory of Open Access Journals (Sweden)

    M. Fujieda

    1999-12-01

    Full Text Available A barrier bucket experiment with two dedicated barrier cavities was performed at the Brookhaven AGS. One of the barrier cavities was a magnetic alloy (MA–loaded cavity and the other was a ferrite-loaded cavity. They generated a single sine wave with a peak voltage of 40 kV at a repetition rate of 351 kHz. A barrier rf system was established with these cavities and five bunches from the AGS booster were accumulated. A total of 3×10^{13} protons were stored without beam loss, and were successfully rebunched and accelerated. The longitudinal emittance growth was observed during accumulation by the barrier bucket, the blowup factor of which was about 3. The longitudinal mismatch between the rf bucket and the beam bunch was the main reason for the emittance growth. The potential distortions by beam loading of the ferrite cavity and the overshooting voltage of the MA cavity disturbed the smooth debunching.

  16. Mucus as a Barrier to Drug Delivery

    DEFF Research Database (Denmark)

    Bøgh, Marie; Nielsen, Hanne Mørck

    2015-01-01

    Viscoelastic mucus lines all mucosal surfaces of the body and forms a potential barrier to mucosal drug delivery. Mucus is mainly composed of water and mucins; high-molecular weight glycoproteins forming an entangled network. Consequently, mucus forms a steric barrier and due to its negative charge...... barrier to drug delivery. Current knowledge of mucus characteristics and barrier properties, as achieved by state-of-the-art methodologies, is the topic of this MiniReview emphasizing the gastrointestinal mucus and an overall focus on oral drug delivery. Cell culture-based in vitro models are well......, studies of peptide and protein drug diffusion in and through mucus and studies of mucus-penetrating nanoparticles are included to illustrate the mucus as a potentially important barrier to obtain sufficient bioavailability of orally administered drugs, and thus an important parameter to address...

  17. Tunnelling through a Gaussian random barrier

    International Nuclear Information System (INIS)

    Bezak, Viktor

    2008-01-01

    A thorough analysis of the tunnelling of electrons through a laterally inhomogeneous rectangular barrier is presented. The barrier height is defined as a statistically homogeneous Gaussian random function. In order to simplify calculations, we assume that the electron energy is low enough in comparison with the mean value of the barrier height. The randomness of the barrier height is defined vertically by a constant variance and horizontally by a finite correlation length. We present detailed calculations of the angular probability density for the tunnelled electrons (i.e. for the scattering forwards). The tunnelling manifests a remarkably diffusive character if the wavelength of the electrons is comparable with the correlation length of the barrier

  18. Barriers in the energy of deformed nuclei

    Directory of Open Access Journals (Sweden)

    V. Yu. Denisov

    2014-06-01

    Full Text Available Interaction energy between two nuclei considering to their deformations is studied. Coulomb and nuclear in-teraction energies, as well as the deformation energies of both nuclei, are taken into account at evaluation of the interaction energy. It is shown that the barrier related to the interaction energy of two nuclei depends on the de-formations and the height of the minimal barrier is evaluated. It is obtained that the heavier nucleus-nucleus sys-tems have large deformation values at the lowest barrier. The difference between the barrier between spherical nuclei and the lowest barrier between deformed nuclei increases with the mass and the charge of the interacting nuclei.

  19. Understanding transport barriers through modelling

    International Nuclear Information System (INIS)

    Rozhansky, V

    2004-01-01

    Models of radial electric field formation are discussed and compared with the results of numerical simulations from fluid transport codes and Monte Carlo codes. A comparison of the fluid and Monte Carlo codes is presented. A conclusion is arrived at that all the simulations do not predict any bifurcation of the electric field, i.e. no bifurcation of poloidal rotation from low to high Mach number values is obtained. In most of the simulations, the radial electric field is close to the neoclassical electric field. The deviation from neoclassical electric field at the separatrix due to the existence of a transitional viscous layer is discussed. Scalings for the shear of the poloidal rotation are checked versus simulation results. It is demonstrated that assuming the critical shear to be of the order of 10 5 s -1 , it is possible to obtain a L-H transition power scaling close to that observed in the experiment. The dependence of the threshold on the magnetic field direction, pellet injection, aspect ratio and other factors are discussed on the basis of existing simulations. Transport codes where transport coefficients depend on the turbulence level and scenario simulations of L-H transition are analysed. However, the details of gyrofluid and gyrokinetic modelling should be discussed elsewhere. Simulations of internal transport barrier (ITB) formation are discussed as well as factors responsible for ITB formation

  20. Institutional distributed energy interconnection barriers

    International Nuclear Information System (INIS)

    Castelaz, S.A.

    2002-01-01

    This PowerPoint presentation provided an introduction to Encorp Inc., a leading provider of network technology and infrastructure management solutions for the distributed energy market. Encorp develops and markets software and hardware technology solutions for communications, control and networking of distributed energy. It is developing and implementing real-time, distributed energy-focused solutions for a wide variety of applications through new products and services which are technology neutral, and easily networked. Encorp controls more than 500 MW of distributed power with a total of 127 customers. This paper reviewed 3 barriers (regulatory, contractual/tariffs, and business practices) based on US experience. The challenge remaining is to determine if microgrids can be used effectively, and to determine the limitations of bi-directional power flows. The key issues regarding how end-users can share the costs and maximize on the benefits of distributed energy resources include: standby service charges, departing load charges, regulatory uncertainty, rate class degradation, lack of incentives for utility cost reduction, and lack of ability to create experimental tariffs. tabs., figs

  1. Tunnel junctions with multiferroic barriers

    Science.gov (United States)

    Gajek, Martin; Bibes, Manuel; Fusil, Stéphane; Bouzehouane, Karim; Fontcuberta, Josep; Barthélémy, Agnès; Fert, Albert

    2007-04-01

    Multiferroics are singular materials that can exhibit simultaneously electric and magnetic orders. Some are ferroelectric and ferromagnetic and provide the opportunity to encode information in electric polarization and magnetization to obtain four logic states. However, such materials are rare and schemes allowing a simple electrical readout of these states have not been demonstrated in the same device. Here, we show that films of La0.1Bi0.9MnO3 (LBMO) are ferromagnetic and ferroelectric, and retain both ferroic properties down to a thickness of 2nm. We have integrated such ultrathin multiferroic films as barriers in spin-filter-type tunnel junctions that exploit the magnetic and ferroelectric degrees of freedom of LBMO. Whereas ferromagnetism permits read operations reminiscent of magnetic random access memories (MRAM), the electrical switching evokes a ferroelectric RAM write operation. Significantly, our device does not require the destructive ferroelectric readout, and therefore represents an advance over the original four-state memory concept based on multiferroics.

  2. 49 CFR 587.18 - Dimensions of fixed rigid barrier.

    Science.gov (United States)

    2010-10-01

    ... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) DEFORMABLE BARRIERS Offset Deformable Barrier § 587.18 Dimensions of fixed rigid barrier. (a) The fixed rigid barrier has a mass of not... 49 Transportation 7 2010-10-01 2010-10-01 false Dimensions of fixed rigid barrier. 587.18 Section...

  3. Model assessment of protective barrier designs

    International Nuclear Information System (INIS)

    Fayer, M.J.; Conbere, W.; Heller, P.R.; Gee, G.W.

    1985-11-01

    A protective barrier is being considered for use at the Hanford site to enhance the isolation of previously disposed radioactive wastes from infiltrating water, and plant and animal intrusion. This study is part of a research and development effort to design barriers and evaluate their performance in preventing drainage. A fine-textured soil (the Composite) was located on the Hanford site in sufficient quantity for use as the top layer of the protective barrier. A number of simulations were performed by Pacific Northwest Laboratory to analyze different designs of the barrier using the Composite soil as well as the finer-textured Ritzville silt loam and a slightly coarser soil (Coarse). Design variations included two rainfall rates (16.0 and 30.1 cm/y), the presence of plants, gravel mixed into the surface of the topsoil, an impermeable boundary under the topsoil, and moving the waste form from 10 to 20 m from the barrier edge. The final decision to use barriers for enhanced isolation of previously disposed wastes will be subject to decisions resulting from the completion of the Hanford Defense Waste Environmental Impact Statement, which addresses disposal of Hanford defense high-level and transuranic wastes. The one-dimensional simulation results indicate that each of the three soils, when used as the top layer of the protective barrier, can prevent drainage provided plants are present. Gravel amendments to the upper 30 cm of soil (without plants) reduced evaporation and allowed more water to drain

  4. Numerical simulations of capillary barrier field tests

    International Nuclear Information System (INIS)

    Morris, C.E.; Stormont, J.C.

    1997-01-01

    Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior

  5. Shakeoff Ionization near the Coulomb Barrier Energy

    Science.gov (United States)

    Sharma, Prashant; Nandi, T.

    2017-11-01

    We measure the projectile K x-ray spectra as a function of the beam energies around the Coulomb barrier in different collision systems. The energy is scanned in small steps around the barrier aiming to explore the nuclear effects on the elastically scattered projectile ions. The variation of the projectile x-ray energy with the ion-beam energies exhibits an unusual increase in between the interaction barrier and fusion barrier energies. This additional contribution to the projectile ionization can be attributed to the shakeoff of outer-shell electrons of the projectile ions due to the sudden nuclear recoil (˜10-21 sec ) caused by the attractive nuclear potential, which gets switched on near the interaction barrier energy. In the sudden approximation limit, the theoretical shakeoff probability calculation due to the nuclear recoil explains the observed data well. In addition to its fundamental interest, such processes can play a significant role in dark matter detection through the possible mechanism of x-ray emissions, where the weakly interacting massive particle-nucleus elastic scattering can lead to the nuclear-recoil-induced inner-shell vacancy creations. Furthermore, the present work may provide new prospects for atomic physics research at barrier energies as well as provide a novel technique to perform barrier distribution studies for two-body systems.

  6. Overcoming natural replication barriers: differential helicase requirements.

    Science.gov (United States)

    Anand, Ranjith P; Shah, Kartik A; Niu, Hengyao; Sung, Patrick; Mirkin, Sergei M; Freudenreich, Catherine H

    2012-02-01

    DNA sequences that form secondary structures or bind protein complexes are known barriers to replication and potential inducers of genome instability. In order to determine which helicases facilitate DNA replication across these barriers, we analyzed fork progression through them in wild-type and mutant yeast cells, using 2-dimensional gel-electrophoretic analysis of the replication intermediates. We show that the Srs2 protein facilitates replication of hairpin-forming CGG/CCG repeats and prevents chromosome fragility at the repeat, whereas it does not affect replication of G-quadruplex forming sequences or a protein-bound repeat. Srs2 helicase activity is required for hairpin unwinding and fork progression. Also, the PCNA binding domain of Srs2 is required for its in vivo role of replication through hairpins. In contrast, the absence of Sgs1 or Pif1 helicases did not inhibit replication through structural barriers, though Pif1 did facilitate replication of a telomeric protein barrier. Interestingly, replication through a protein barrier but not a DNA structure barrier was modulated by nucleotide pool levels, illuminating a different mechanism by which cells can regulate fork progression through protein-mediated stall sites. Our analyses reveal fundamental differences in the replication of DNA structural versus protein barriers, with Srs2 helicase activity exclusively required for fork progression through hairpin structures.

  7. Permanent isolation surface barrier development plan

    International Nuclear Information System (INIS)

    Wing, N.R.

    1994-01-01

    The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no open-quotes provenclose quotes long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems

  8. Permanent isolation surface barrier development plan

    Energy Technology Data Exchange (ETDEWEB)

    Wing, N.R.

    1994-01-01

    The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no {open_quotes}proven{close_quotes} long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems.

  9. Collisions between heavy nuclei near the barrier

    International Nuclear Information System (INIS)

    Henning, W.

    1988-05-01

    Detailed information has recently become available on the reaction behavior in very heavy nuclear systems close to the Coulomb barrier. Starting from an experimental study of the distribution of the reaction strength above and below the barrier, the dominant reaction channels of quasi-elastic and strongly-damped processes are examined. With decreasing incident energy, the sub-barrier collisions are increasingly dominated by quasi-elastic processes. From the division of internal excitation energy, new information is obtained on the nature of the dissipative processes. (orig.)

  10. Barriers to cervical cancer screening uptake among rural women in ...

    African Journals Online (AJOL)

    [5] Among Asian-American women, psychosocial ... poorly-trained personnel were health system-related barriers. In sub-Saharan ... explored the religious and cultural barriers to cervical screening ... perceived barriers to screening uptake.

  11. Performance of dynamic safety barriers-Structuring, modelling and visualization

    OpenAIRE

    Wikdahl, Olga

    2014-01-01

    The main objective of this master thesis is to discuss performance of dynamic safety barriers. A comprehensive literature review is performed in order to get understanding what dynamic safety barrier is. Three different concepts of dynamic safety barriers based on various meanings of dynamic were derived from the literature review: - dynamic safety barriers related to motion or physical force - dynamic safety barriers as updated barriers from dynamic risk analysis - dynamic safety ...

  12. Market and Policy Barriers to Energy Storage Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Bhatnagar, Dhruv [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Currier, Aileen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hernandez, Jacquelynne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ma, Ookie [Dept. of Energy (DOE), Washington DC (United States) Office of Energy Efficiency and Renewable Energy; Kirby, Brendan [Consultant

    2013-09-01

    Electric energy storage technologies can provide numerous grid services; there are a number of factors that restrict their current deployment. The most significant barrier to deployment is high capital costs, though several recent deployments indicate that capital costs are decreasing and energy storage may be the preferred economic alternative in certain situations. However, a number of other market and regulatory barriers persist, limiting further deployment. These barriers can be categorized into regulatory barriers, market (economic) barriers, utility and developer business model barriers, cross-cutting barriers and technology barriers.

  13. Low-impact, high toughness transportation barriers.

    Science.gov (United States)

    2012-10-01

    Alternatives to existing transportation truck escape ramps and crash barriers are examined using arrays of : wood, bamboo, and fiberglass structural elements that act as energy absorbers as they deform. The : behaviors of each material type are analy...

  14. Addressing the Barriers to Young Women's Economic ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    -understand how women overcome barriers to economic empowerment ... the United Kingdom's Department for International Development, The William and Flora ... Call for new OWSD Fellowships for Early Career Women Scientists now open.

  15. Nuclear reorganization barriers to electron transfer

    International Nuclear Information System (INIS)

    Sutin, N.; Brunschwig, B.S.; Creutz, C.; Winkler, J.R.

    1988-01-01

    The nuclear barrier to electron transfer arises from the need for reorganization of intramolecular and solvent internuclear distances prior to electron transfer. For reactions with relatively small driving force (''normal'' free-energy region) the nuclear factors and rates increase as intrinsic inner-shell and outer-shell barriers decrease; this is illustrated by data for transition metal complexes in their ground electronic states. By contrast, in the inverted free-energy region, rates and nuclear factors decrease with decreasing ''intrinsic'' barriers; this is illustrated by data for the decay of charge-transfer excited states. Several approaches to the evaluation of the outer-shell barrier are explored in an investigation of the distance dependence of the nuclear factor in intramolecular electron-transfer processes. 39 refs., 14 figs., 3 tabs

  16. Barrier Cavities in the Brookhaven AGS

    International Nuclear Information System (INIS)

    Blaskiewicz, M.; Brennan, J. M.; Roser, T.; Smith, K.; Spitz, R.; Zaltsman, A.; Fujieda, M.; Iwashita, Y.; Noda, A.; Yoshii, M.; Mori, Y.; Ohmori, C.; Sato, Y.

    1999-01-01

    In collaboration with KEK two barrier cavities, each generating 40 kV per turn have been installed in the Brookhaven AGS. Machine studies are described and their implications for high intensity operations are discussed

  17. Break down these barriers to medication safety.

    Science.gov (United States)

    2009-06-01

    Survey says of 2,200 ED nurses from 131 EDs, barriers to complying with medication-related NPSGs are common. Consider additional education of employees. One hospital uses computerized charting system to quicken triage process.

  18. DOE UST interim subsurface barrier technologies workshop

    International Nuclear Information System (INIS)

    1992-09-01

    This document contains information which was presented at a workshop regarding interim subsurface barrier technologies that could be used for underground storage tanks, particularly the tank 241-C-106 at the Hanford Reservation

  19. Cost and effectiveness of radon barrier systems

    International Nuclear Information System (INIS)

    Baker, E.G.; Freeman, H.D.; Hartley, J.N.; Gee, G.W.

    1982-12-01

    Earthen, asphalt, and multilayer radon barrier systems can all provide reduction in the amount of radon gas released from uranium mill tailings. Pacific Northwest Laboratory field tested all three types of covers at Grand Junction, Colorado during the summer of 1981. All nine individual radon barrier systems tested currently meet the EPA standard for radon flux of 20 pCi m - 2 s - 1 . The cost of the asphalt and 3m earthen covers were about the same at the field test. Multilayer covers were significantly more costly. Cost estimates for three high priority western sites indicate 3m of earthen cover is the least costly radon barrier when earthen material is available at or near the disposal site. If earthen material must be imported more than 8 to 10 km asphalt and possibly multilayer radon barriers can be cost effective

  20. Markers for blood-brain barrier integrity

    DEFF Research Database (Denmark)

    Saunders, Norman R; Dziegielewska, Katarzyna M; Møllgård, Kjeld

    2015-01-01

    In recent years there has been a resurgence of interest in brain barriers and various roles their intrinsic mechanisms may play in neurological disorders. Such studies require suitable models and markers to demonstrate integrity and functional changes at the interfaces between blood, brain......, and cerebrospinal fluid. Studies of brain barrier mechanisms and measurements of plasma volume using dyes have a long-standing history, dating back to the late nineteenth-century. Their use in blood-brain barrier studies continues in spite of their known serious limitations in in vivo applications. These were well...... known when first introduced, but seem to have been forgotten since. Understanding these limitations is important because Evans blue is still the most commonly used marker of brain barrier integrity and those using it seem oblivious to problems arising from its in vivo application. The introduction...

  1. Fusion barrier distributions - What have we learned?

    International Nuclear Information System (INIS)

    Hinde, D. J.; Dasgupta, M.

    1998-01-01

    The study of nuclear fusion received a strong impetus from the realisation that an experimental fusion barrier distribution could be determined from precisely measured fusion cross-sections. Experimental data for different reactions have shown in the fusion barrier distributions clear signatures of a range of nuclear excitations, for example the effects of static quadrupole and hexadecapole deformations, single- and double-phonon states, transfer of nucleons, and high-lying excited states. The improved understanding of fusion barrier distributions allows more reliable prediction of fusion angular momentum distributions, which aids interpretation of fission probabilities and fission anisotropies, and understanding of the population of super-deformed bands for nuclear structure studies. Studies of the relationship between the fusion barrier distribution and the extra-push energy should improve our understanding of the mechanism of the extra-push effect, and may help to predict new ways of forming very heavy or super-heavy nuclei

  2. Barriers to learning from incidents and accidents

    NARCIS (Netherlands)

    Dechy, N.; Dien, Y.; Drupsteen, L.; Felicio, A.; Cunha, C.; Roed-Larsen, S.; Marsden, E.; Tulonen, T.; Stoop, J.; Strucic, M.; Vetere Arellano, A.L.; Vorm, J.K.J. van der; Benner, L.

    2015-01-01

    This document provides an overview of knowledge concerning barriers to learning from incidents and accidents. It focuses on learning from accident investigations, public inquiries and operational experience feedback, in industrial sectors that are exposed to major accident hazards. The document

  3. Barriers to Physical Activity on University Student

    Science.gov (United States)

    Jajat; Sultoni, K.; Suherman, A.

    2017-03-01

    The purpose of the research is to analyze the factors that become barriers to physical activity in university students based on physical activity level. An internet-based survey was conducted. The participants were 158 University students from Universitas Pendidikan Indonesia. Barriers to Physical Activity Quiz (BPAQ) were used to assessed the factors that become barriers to physical activity in university students. IPAQ (short form) were used to assessed physical activity level. The results show there was no differences BPAQ based on IPAQ level. But when analyzed further based on seven factors barriers there are differences in factors “social influence and lack of willpower” based IPAQ level. Based on this it was concluded that the “influence from other and lack of willpower” an inhibiting factor on students to perform physical activity.

  4. Nuclear structure and fusion at the barrier

    International Nuclear Information System (INIS)

    Reisdorf, W.

    1985-01-01

    A comparative study of measured fusion excitation functions in the vicinity of the barrier reveals nuclear structure effects, due in particular to the coupling of the fusion process to direct-reaction channels. (orig.)

  5. Communicating across barriers at home and abroad

    Science.gov (United States)

    McDonald, J. W.

    This paper intends to catalyze the exchange of experience among technical communicators in meeting the challenge of communicating across a multitude of barriers: linguistic, disciplinary, cultural, political, intellectual, and emotional.

  6. JET internal transport barriers: experiment vs theory

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, B [Associazione Euratom - ENEA sulla Fusione, C.R. Frascati, CP 65, I-00040, Frascati, Rome (Italy); Crisanti, F [Associazione Euratom - ENEA sulla Fusione, C.R. Frascati, CP 65, I-00040, Frascati, Rome (Italy); Parail, V [Euratom/UKAEA Fusion Association, Cuhlam Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Maget, P [Association Euratom - CEA pour la Fusion, CEA Cadarache, F-13108 Saint Paul-lez-Durance Cedex (France); Baranov, Y [Euratom/UKAEA Fusion Association, Cuhlam Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Becoulet, A [Association Euratom - CEA pour la Fusion, CEA Cadarache, F-13108 Saint Paul-lez-Durance Cedex (France); Castaldo, C [Associazione Euratom - ENEA sulla Fusione, C.R. Frascati, CP 65, I-00040, Frascati, Rome (Italy); Challis, C D [Euratom/UKAEA Fusion Association, Cuhlam Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Angelis, R De [Associazione Euratom - ENEA sulla Fusione, C.R. Frascati, CP 65, I-00040, Frascati, Rome (Italy); Garbet, X [Association Euratom - CEA pour la Fusion, CEA Cadarache, F-13108 Saint Paul-lez-Durance Cedex (France); Giroud, C [Association Euratom - CEA pour la Fusion, CEA Cadarache, F-13108 Saint Paul-lez-Durance Cedex (France); Hawkes, N [Euratom/UKAEA Fusion Association, Cuhlam Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Joffrin, E [Association Euratom - CEA pour la Fusion, CEA Cadarache, F-13108 Saint Paul-lez-Durance Cedex (France); Litaudon, X [Association Euratom - CEA pour la Fusion, CEA Cadarache, F-13108 Saint Paul-lez-Durance Cedex (France); Mazon, D [Association Euratom - CEA pour la Fusion, CEA Cadarache, F-13108 Saint Paul-lez-Durance Cedex (France); Riva, M [Associazione Euratom - ENEA sulla Fusione, C.R. Frascati, CP 65, I-00040, Frascati, Rome (Italy); Zastrow, K D [Euratom/UKAEA Fusion Association, Cuhlam Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

    2003-06-01

    A large variety of JET discharges with internal transport barriers (ITBs) has been analysed in order to determine the main features which characterize turbulence stabilization at the barrier. It is found that the location of barriers is well correlated with regions where the ExB flow shearing rate exceeds the linear growth rate of the ion temperature gradient mode instability ({gamma}{sub {eta}{sub i}}). A key point is the dependence of {gamma}{sub {eta}{sub i}} on the magnetic shear: in the discharges of this database the reduction of {gamma}{sub {eta}{sub i}} associated to very low or null magnetic shear favours the formation of an ITB. After the ITB formation a positive feedback occurs in which the ExB flow shear mechanism has the leading role and the position of the barrier may be no longer linked to the low shear region.

  7. Overcoming Barriers to Shared Decision Making

    Science.gov (United States)

    ... a social worker can help. Barrier: Language differences Solution: More than 13 million people in the U.S. age 5 and older speak little or no English, according to the U.S. Census Bureau. Some hospitals ...

  8. Evapotranspiration studies for protective barriers: Experimental plans

    International Nuclear Information System (INIS)

    Link, S.O.; Waugh, W.J.

    1989-11-01

    This document describes a general theory and experimental plans for predicting evapotranspiration in support of the Protective Barrier Program. Evapotranspiration is the combined loss of water from plants and soil surfaces to the atmosphere. 45 refs., 1 fig., 4 tabs

  9. Advanced house air-barrier systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, R.K. [Natural Resources Canada, Ottawa, ON (Canada)

    1996-08-01

    Air barrier systems used in modern Canadian airtight homes were discussed. The Advanced Houses Program sets its airtightness requirements at 1.5 air changes per hour at 50 Pascals pressure difference (ACH{sub 5}0). In recent tests of 10 houses, it was suggested that a better airtightness level was attainable with average airtightness of about 1.0 ACH{sub 5}0. Six of the homes tested did not use the traditional polyethylene approach. Two of the houses used the airtight drywall approach, one used a foam system, and three used exterior air barriers. The advantages and disadvantages of each system was described, including cost effectiveness, cost reduction, performance and installation advantages. The confusion between an air barrier and a vapour diffusion retarder was explained. Exterior air barriers showed the greatest potential for meeting airtightness requirements at reasonable cost. 5 refs., 3 tabs.

  10. Electron tunneling across a tunable potential barrier

    International Nuclear Information System (INIS)

    Mangin, A; Anthore, A; Rocca, M L Della; Boulat, E; Lafarge, P

    2009-01-01

    We present an experiment where the elementary quantum electron tunneling process should be affected by an independent gate voltage parameter. We have realized nanotransistors where the source and drain electrodes are created by electromigration inducing a nanometer sized gap acting as a tunnel barrier. The barrier potential shape is in first approximation considered trapezoidal. The application of a voltage to the gate electrode close to the barrier region can in principle affect the barrier shape. Simulations of the source drain tunnel current as a function of the gate voltage predict modulations as large as one hundred percent. The difficulty of observing the predicted behaviour in our samples might be due to the peculiar geometry of the realized tunnel junction.

  11. Stochastic transport of particles across single barriers

    International Nuclear Information System (INIS)

    Kreuter, Christian; Siems, Ullrich; Henseler, Peter; Nielaba, Peter; Leiderer, Paul; Erbe, Artur

    2012-01-01

    Transport phenomena of interacting particles are of high interest for many applications in biology and mesoscopic systems. Here we present measurements on colloidal particles, which are confined in narrow channels on a substrate and interact with a barrier, which impedes the motion along the channel. The substrate of the particle is tilted in order for the particles to be driven towards the barrier and, if the energy gained by the tilt is large enough, surpass the barrier by thermal activation. We therefore study the influence of this barrier as well as the influence of particle interaction on the particle transport through such systems. All experiments are supported with Brownian dynamics simulations in order to complement the experiments with tests of a large range of parameter space which cannot be accessed in experiments.

  12. Frozen soil barriers for hazardous waste confinement

    International Nuclear Information System (INIS)

    Dash, J.G.; Leger, R.; Fu, H.Y.

    1997-01-01

    Laboratory and full field measurements have demonstrated the effectiveness of artificial ground freezing for the containment of subsurface hazardous and radioactive wastes. Bench tests and a field demonstration have shown that cryogenic barriers are impenetrable to aqueous and non aqueous liquids. As a result of the successful tests the US Department of Energy has designated frozen ground barriers as one of its top ten remediation technologies

  13. Phonic Attenuation due to Screen-Barriers

    Directory of Open Access Journals (Sweden)

    Vasile Bacria

    2011-10-01

    Full Text Available The technique of noise decreasing admits two basic approaches: an active approach and a passive one. In the frame of passive method one can count the employment of screen-barriers. In this paper we present some considerations on sound attenuation due to screen-barriers emphasizing the elements which influence it. The elucidation of these elements is made by measurements. The obtained results can be applied in every other practical situation concerning the protection against noise.

  14. Immigrant language barriers and house prices

    OpenAIRE

    Fischer, Andreas M.

    2011-01-01

    Are language skills important in explaining the nexus between house prices and immigrant inflows? The language barrier hypothesis says immigrants from a non common language country value amenities more than immigrants from common language countries.> ; In turn, immigrants from non common language countries are less price sensitive to house price changes than immigrants from a common language country. Tests of the language barrier hypothesis with Swiss house prices show that an immigration inf...

  15. Using Frozen Barriers for Containment of Contaminants

    Science.gov (United States)

    2017-09-21

    barriers are constructed of grout slurry and plastic or steel sheet pilings. Circumferential barriers can be used to completely enclose a source of...2.1.1 Slurry walls A soil-bentonite slurry trench cutoff wall (slurry wall) is excavated and backfilled with grout, cement , or soil-bentonite...installation requires a mixing area, and there is a substantial amount of excavation and the need to dispose of spoil. The advantages of cement -based

  16. Structural Stability of Tokamak Equilibrium: Transport Barriers

    Energy Technology Data Exchange (ETDEWEB)

    Solano, E. R.

    2001-07-01

    A generalised theory of structural stability of differential equations is introduced and applied to the Grad-Shafranov equation. It is discussed how the formation and loss of transport barrier could be associated with the appearance/disappearance of equilibria. The equilibrium conjecture is presented: transport barriers are associated with locally diamagnetic regions in the plasma, and affected by the paramagnetism of the bootstrap current. (Author) 18 refs.

  17. Breaching barriers to collaboration in public spaces

    DEFF Research Database (Denmark)

    Heinemann, Trine; Mitchell, Robb

    2014-01-01

    Technology provoking disparate individuals to collaborate or share experiences in the public space faces a difficult barrier, namely the ordinary social order of urban places. We employed the notion of the breaching experiment to explore how this barrier might be overcome. We analyse responses...... of life in public spaces. Arising from this, we argue for the importance of qualities such as availability, facilitation, perspicuous settings, and perspicuous participants to encourage and support co-located strangers to collaborate and share experiences....

  18. ENA study cites barriers to NPSG compliance.

    Science.gov (United States)

    2009-04-01

    There are many barriers to compliance with the National Patient Safety Goals, as a recent study shows. However, emergency medicine experts say there are several strategies you can adopt to help overcome those barriers. Send the right message to your staff by establishing a culture of shared responsibility for safety. Establish scripts for talking with patients. Standardization will help ensure they are getting the correct information. Put standardized abbreviations on posters in your department, and list them on your medication reconciliation form.

  19. Nuclear energy technology transfer: the security barriers

    International Nuclear Information System (INIS)

    Rinne, R.L.

    1975-08-01

    The problems presented by security considerations to the transfer of nuclear energy technology are examined. In the case of fusion, the national security barrier associated with the laser and E-beam approaches is discussed; for fission, the international security requirements, due to the possibility of the theft or diversion of special nuclear materials or sabotage of nuclear facilities, are highlighted. The paper outlines the nuclear fuel cycle and terrorist threat, examples of security barriers, and the current approaches to transferring technology. (auth)

  20. Barriers in EU retail financial markets

    OpenAIRE

    Micuda, Dan

    2007-01-01

    Looking at the retail financial markets and identifing a number of ‘‘natural’’ and ‘‘policy induced’’ obstacles to free trade. We use the term ‘‘natural’’ barriers to refer to those arising as a result of different cultures or consumer preferences, while different state tax policies or regulations are classified as ‘‘policy induced’’ barriers.

  1. Structuring unbreakable hydrophobic barriers in paper

    Science.gov (United States)

    Nargang, Tobias M.; Kotz, Frederik; Rapp, Bastian E.

    2018-02-01

    Hydrophobic barriers are one of the key elements of microfluidic paper based analytical devices (μPADs).μPADs are simple and cost efficient and they can be carried out without the need of high standard laboratories. To carry out such a test a method is needed to create stable hydrophobic barriers. Commonly used methods like printing wax or polystyrene have the major drawback that these barriers are stiff and break if bended which means they will no longer be able to retain a liquid sample. Here we present silanes to structure hydrophobic barriers via polycondensation and show a silanization method which combines the advantages of flexible silane/siloxane layers with the short processing times of UV-light based structuring. The barriers are created by using methoxy silanes which are mixed with a photo acid generator (PAG) as photoinitiator. Also a photosensitizer was given to the mixture to increase the effectiveness of the PAG. After the PAG is activated by UV-light the silane is hydrolyzed and coupled to the cellulose via polycondensation. The created hydrophobic barriers are highly stable and do not break if being bended.

  2. Field study plan for alternate barriers

    International Nuclear Information System (INIS)

    Freeman, H.D.; Gee, G.W.; Relyea, J.F.

    1989-05-01

    Pacific Northwest Laboratory (PNL) is providing technical assistance in selecting, designing, evaluating, and demonstrating protective barriers. As part of this technical assistance effort, asphalt, clay, and chemical grout will be evaluated for use as alternate barriers. The purpose of the subsurface layer is to reduce the likelihood that extreme events (i.e., 100-year maximum storms, etc.) will cause significant drainage through the barrier. The tests on alternate barriers will include laboratory and field analysis of the subsurface layer performance. This field test plan outlines the activities required to test and design subsurface moisture barriers. The test plan covers activities completed in FY 1988 and planned through FY 1992 and includes a field-scale test of one or more of the alternate barriers to demonstrate full-scale application techniques and to provide performance data on a larger scale. Tests on asphalt, clay, and chemical grout were initiated in FY 1988 in small (30.5 cm diameter) tube-layer lysimeters. The parameters used for testing the materials were different for each one. The tests had to take into account the differences in material characteristics and response to change in conditions, as well as information provided by previous studies. 33 refs., 8 figs., 1 tab

  3. Treatment of barrier evolution: the SKB perspective

    International Nuclear Information System (INIS)

    Hedin, A.

    2002-01-01

    This paper serves as a point of departure for the discussions to be held within the Working Group of Technical Topic entitled 'Barriers and System Performances within a safety case: Their functioning and Evolution with Time'. The paper gives the SKB perspective of the issues to be discussed within the Working Group for this Topic. The following issues to be discussed by the Working Group are: What is the role of each barrier as a function of time or in the different time frames? What is its contribution to the overall system performance or safety as a function of time? Which are the main uncertainties on the performance of barriers in the timescales? To what extent should we enhance the robustness of barriers because of the uncertainties of some component behaviour with time? What is the requested or required performance versus the expected or realistic or conservative behaviour with time? How are these safety margins used as arguments in a safety case? What is the issue associated with the geosphere stability for different geological systems? How is barriers and system performances as a function of time evaluated (and presented and communicated) in a safety case? What kind of measures are used for siting, designing and optimising robust barriers corresponding to situations that can vary with time? Are human actions considered to be relevant? (authors)

  4. Effect of the barrier properties on the surface part of the barrier discharge

    International Nuclear Information System (INIS)

    Sokolova, M.V.; Zhukov, S.V.

    1998-01-01

    The effect of barrier characteristics on the discharge processes in a barrier discharge was investigated, main attention being paid to the amount and distribution of the charge left on the barrier surface by the volume discharge in the main air gap. The measurements show that the main part of the gap charge is due to the volume part of the discharge. The measured values of the surface charge significantly increase with the voltage applied and with the length of the gas gap, while the dimensions of the charge spot and the distribution of charge density are determined by the barrier properties. (J.U.)

  5. Opportunities and barriers for international bioenergy trade

    International Nuclear Information System (INIS)

    Junginger, Martin; Dam, Jinke van; Zarrilli, Simonetta; Ali Mohamed, Fatin; Marchal, Didier; Faaij, Andre

    2011-01-01

    Recently, the international trade of various bioenergy commodities has grown rapidly, yet this growth is also hampered by some barriers. The aim of this paper is to obtain an overview of what market actors currently perceive as major opportunities and barriers for the development of international bioenergy trade. The work focuses on three bioenergy commodities: bioethanol, biodiesel and wood pellets. Data were collected through an internet-based questionnaire. The majority of the 141 respondents had an industrial background. Geographically, two-thirds were from (mainly Western) Europe, with other minor contributions from all other continents. Results show that import tariffs and the implementation of sustainability certification systems are perceived as (potentially) major barriers for the trade of bioethanol and biodiesel, while logistics are seen mainly as an obstacle for wood pellets. Development of technical standards was deemed more as an opportunity than a barrier for all commodities. Most important drivers were high fossil fuel prices and climate change mitigation policies. Concluding, to overcome some of the barriers, specific actions will be required by market parties and policy makers. Import tariffs for biofuels could be reduced or abolished, linked to multinational trade agreements and harmonization (including provisions on technical standards and sustainability requirements). - Research highlights: → We analyze main barriers for global trade of wood pellets, ethanol and biodiesel. → Import tariffs can be a major barrier for liquid biofuels trade. → Implementation of sustainability certification systems may hamper biofuels trade. → Logistics are seen mainly as an obstacle for the trade of wood pellets. → Development of technical standards are deemed an opportunity for bioenergy trade.

  6. Numerical investigation of dielectric barrier discharges

    Science.gov (United States)

    Li, Jing

    1997-12-01

    A dielectric barrier discharge (DBD) is a transient discharge occurring between two electrodes in coaxial or planar arrangements separated by one or two layers of dielectric material. The charge accumulated on the dielectric barrier generates a field in a direction opposite to the applied field. The discharge is quenched before an arc is formed. It is one of the few non-thermal discharges that operates at atmospheric pressure and has the potential for use in pollution control. In this work, a numerical model of the dielectric barrier discharge is developed, along with the numerical approach. Adaptive grids based on the charge distribution is used. A self-consistent method is used to solve for the electric field and charge densities. The Successive Overrelaxation (SOR) method in a non-uniform grid spacing is used to solve the Poisson's equation in the cylindrically-symmetric coordinate. The Flux Corrected Transport (FCT) method is modified to solve the continuity equations in the non-uniform grid spacing. Parametric studies of dielectric barrier discharges are conducted. General characteristics of dielectric barrier discharges in both anode-directed and cathode-directed streamer are studied. Effects of the dielectric capacitance, the applied field, the resistance in external circuit and the type of gases (O2, air, N2) are investigated. We conclude that the SOR method in an adaptive grid spacing for the solution of the Poisson's equation in the cylindrically-symmetric coordinate is convergent and effective. The dielectric capacitance has little effect on the g-factor of radical production, but it determines the strength of the dielectric barrier discharge. The applied field and the type of gases used have a significant role on the current peak, current pulse duration and radical generation efficiency, discharge strength, and microstreamer radius, whereas the external series resistance has very little effect on the streamer properties. The results are helpful in

  7. A comparison of freeway median crash frequency, severity, and barrier strike outcomes by median barrier type.

    Science.gov (United States)

    Russo, Brendan J; Savolainen, Peter T

    2018-08-01

    Median-crossover crashes are among the most hazardous events that can occur on freeways, often resulting in severe or fatal injuries. The primary countermeasure to reduce the occurrence of such crashes is the installation of a median barrier. When installation of a median barrier is warranted, transportation agencies are faced with the decision among various alternatives including concrete barriers, beam guardrail, or high-tension cable barriers. Each barrier type differs in terms of its deflection characteristics upon impact, the required installation and maintenance costs, and the roadway characteristics (e.g., median width) where installation would be feasible. This study involved an investigation of barrier performance through an in-depth analysis of crash frequency and severity data from freeway segments where high-tension cable, thrie-beam, and concrete median barriers were installed. A comprehensive manual review of crash reports was conducted to identify crashes in which a vehicle left the roadway and encroached into the median. This review also involved an examination of crash outcomes when a barrier strike occurred, which included vehicle containment, penetration, or re-direction onto the travel lanes. The manual review of crash reports provided critical supplementary information through narratives and diagrams not normally available through standard fields on police crash report forms. Statistical models were estimated to identify factors that affect the frequency, severity, and outcomes of median-related crashes, with particular emphases on differences between segments with varying median barrier types. Several roadway-, traffic-, and environmental-related characteristics were found to affect these metrics, with results varying across the different barrier types. The results of this study provide transportation agencies with important guidance as to the in-service performance of various types of median barrier. Copyright © 2018 Elsevier Ltd. All rights

  8. Circularly polarized antennas for active holographic imaging through barriers

    Science.gov (United States)

    McMakin, Douglas L [Richland, WA; Severtsen, Ronald H [Richland, WA; Lechelt, Wayne M [West Richland, WA; Prince, James M [Kennewick, WA

    2011-07-26

    Circularly-polarized antennas and their methods of use for active holographic imaging through barriers. The antennas are dielectrically loaded to optimally match the dielectric constant of the barrier through which images are to be produced. The dielectric loading helps to remove barrier-front surface reflections and to couple electromagnetic energy into the barrier.

  9. A Learner Perspective on Barriers to E-Learning

    Science.gov (United States)

    Becker, Karen; Newton, Cameron; Sawang, Sukanlaya

    2013-01-01

    This study aims to identify and categorize barriers to e-learning adoption and the relative impact of those barriers on learners. It contributes to the understanding of learner perceptions of barriers, the different types of barriers and their relative importance. This study used a quantitative methodology grounded in previous literature. The…

  10. Model assessment of protective barrier designs: Part 2

    International Nuclear Information System (INIS)

    Fayer, M.J.

    1987-11-01

    Protective barriers are being considered for use at the Hanford Site to enhance the isolation of radioactive wastes from water, plant, and animal intrusion. This study assesses the effectiveness of protective barriers for isolation of wastes from water. In this report, barrier designs are reviewed and several barrier modeling assumptions are tested. 20 refs., 16 figs., 6 tabs

  11. Near-Surface Engineered Environmental Barrier Integrity

    International Nuclear Information System (INIS)

    Piet, S.J.; Breckenridge, R.P.

    2002-01-01

    The INEEL Environmental Systems Research and Analysis (ESRA) program has launched a new R and D project on Near-Surface Engineered Environmental Barrier Integrity to increase knowledge and capabilities for using engineering and ecological components to improve the integrity of near-surface barriers used to confine contaminants from the public and the environment. The knowledge gained and the capabilities built will help verify the adequacy of past remedial decisions and enable improved solutions for future cleanup decisions. The research is planned to (a) improve the knowledge of degradation mechanisms (weathering, biological, geological, chemical, radiological, and catastrophic) in times shorter than service life, (b) improve modeling of barrier degradation dynamics, (c) develop sensor systems to identify degradation prior to failure, and (d) provide a better basis for developing and testing of new barrier systems to increase reliability and reduce the risk of failure. Our project combine s selected exploratory studies (benchtop and field scale), coupled effects accelerated aging testing and the meso-scale, testing of new monitoring concepts, and modeling of dynamic systems. The performance of evapo-transpiration, capillary, and grout-based barriers will be examined

  12. Surface stability test plan for protective barriers

    International Nuclear Information System (INIS)

    Ligotke, M.W.

    1989-01-01

    Natural-material protective barriers for long-term isolation of buried waste have been identified as integral components of a plan to isolate a number of Hanford defense waste sites. Standards currently being developed for internal and external barrier performance will mandate a barrier surface layer that is resistant to the eolian erosion processes of wind erosion (deflation) and windborne particle deposition (formation of sand dunes). Thus, experiments are needed to measure rates of eolian erosion processes impacting those surfaces under different surface and climatological conditions. Data from these studies will provide information for use in the evaluation of selected surface layers as a means of providing stable cover over waste sites throughout the design life span of protective barriers. The multi-year test plan described in this plan is directed at understanding processes of wind erosion and windborne particle deposition, providing measurements of erosion rates for models, and suggesting construction materials and methods for reducing the effect of long-term eolian erosion on the barrier. Specifically, this plan describes possible methods to measure rates of eolian erosion, including field and laboratory procedure. Advantages and disadvantages of laboratory (wind tunnel) tests are discussed, and continued wind tunnel tests are recommended for wind erosion studies. A comparison between field and wind tunnel erosive forces is discussed. Plans for testing surfaces are described. Guidance is also presented for studying the processes controlling sand dune and blowout formation. 24 refs., 7 figs., 3 tabs

  13. Field emission from finite barrier quantum structures

    Energy Technology Data Exchange (ETDEWEB)

    Biswas Sett, Shubhasree, E-mail: shubhasree24@gmail.com [The Institution of Engineers - India, 8, Gokhale Road, Kolkata 700 020 (India); Bose, Chayanika, E-mail: chayanikab@ieee.org [Electronics and Telecommunication Engg. Dept., Jadavpur University, Kolkata 700 032 (India)

    2014-10-01

    We study field emission from various finite barrier quasi-low dimensional structures, taking image force into account. To proceed, we first formulate an expression for field emission current density from a quantum dot. Transverse dimensions of the dot are then increased in turn, to obtain current densities respectively from quantum wire and quantum well with infinite potential energy barriers. To find out field emission from finite barrier structures, the above analysis is followed with a correction in the energy eigen values. In course, variations of field emission current density with strength of the applied electric field and structure dimensions are computed considering n-GaAs and n-GaAs/Al{sub x}Ga{sub 1−x}As as the semiconductor materials. In each case, the current density is found to increase exponentially with the applied field, while it oscillates with structure dimensions. The magnitude of the emission current is less when the image force is not considered, but retains the similar field dependence. In all cases, the field emission from infinite barrier structures exceeds those from respective finite barrier ones.

  14. Barrier properties of cultured retinal pigment epithelium.

    Science.gov (United States)

    Rizzolo, Lawrence J

    2014-09-01

    The principal function of an epithelium is to form a dynamic barrier that regulates movement between body compartments. Each epithelium is specialized with barrier functions that are specific for the tissues it serves. The apical surface commonly faces a lumen, but the retinal pigment epithelium (RPE) appears to be unique by a facing solid tissue, the sensory retina. Nonetheless, there exists a thin (subretinal) space that can become fluid filled during pathology. RPE separates the subretinal space from the blood supply of the outer retina, thereby forming the outer blood-retinal barrier. The intricate interaction between the RPE and sensory retina presents challenges for learning how accurately culture models reflect native behavior. The challenge is heightened by findings that detail the variation of RPE barrier proteins both among species and at different stages of the life cycle. Among the striking differences is the expression of claudin family members. Claudins are the tight junction proteins that regulate ion diffusion across the spaces that lie between the cells of a monolayer. Claudin expression by RPE varies with species and life-stage, which implies functional differences among commonly used animal models. Investigators have turned to transcriptomics to supplement functional studies when comparing native and cultured tissue. The most detailed studies of the outer blood-retinal barrier have focused on human RPE with transcriptome and functional studies reported for human fetal, adult, and stem-cell derived RPE. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Vertical barriers with increased sorption capacities

    International Nuclear Information System (INIS)

    Bradl, H.B.

    1997-01-01

    Vertical barriers are commonly used for the containment of contaminated areas. Due to the very small permeability of the barrier material which is usually in the order of magnitude of 10-10 m/s or less the advective contaminant transport can be more or less neglected. Nevertheless, there will always be a diffusive contaminant transport through the barrier which is caused by the concentration gradient. Investigations have been made to increase the sorption capacity of the barrier material by adding substances such as organoclays, zeolites, inorganic oxides and fly ashes. The contaminants taken into account where heavy metals (Pb) and for organic contaminants Toluole and Phenantrene. The paper presents results of model calculations and experiments. As a result, barrier materials can be designed 'tailor-made' depending on the individual contaminant range of each site (e.g. landfills, gasworks etc.). The parameters relevant for construction such as rheological properties, compressive strength and permeability are not affected by the addition of the sorbents

  16. Visual selective attention with virtual barriers.

    Science.gov (United States)

    Schneider, Darryl W

    2017-07-01

    Previous studies have shown that interference effects in the flanker task are reduced when physical barriers (e.g., hands) are placed around rather than below a target flanked by distractors. One explanation of this finding is the referential coding hypothesis, whereby the barriers serve as reference objects for allocating attention. In five experiments, the generality of the referential coding hypothesis was tested by investigating whether interference effects are modulated by the placement of virtual barriers (e.g., parentheses). Modulation of flanker interference was found only when target and distractors differed in size and the virtual barriers were beveled wood-grain objects. Under these conditions and those of previous studies, the author conjectures that an impression of depth was produced when the barriers were around the target, such that the target was perceived to be on a different depth plane than the distractors. Perception of depth in the stimulus display might have led to referential coding of the stimuli in three-dimensional (3-D) space, influencing the allocation of attention beyond the horizontal and vertical dimensions. This 3-D referential coding hypothesis is consistent with research on selective attention in 3-D space that shows flanker interference is reduced when target and distractors are separated in depth.

  17. Schottky barrier MOSFET systems and fabrication thereof

    Science.gov (United States)

    Welch, J.D.

    1997-09-02

    (MOS) device systems-utilizing Schottky barrier source and drain to channel region junctions are disclosed. Experimentally derived results which demonstrate operation of fabricated N-channel and P-channel Schottky barrier (MOSFET) devices, and of fabricated single devices with operational characteristics similar to (CMOS) and to a non-latching (SRC) are reported. Use of essentially non-rectifying Schottky barriers in (MOS) structures involving highly doped and the like and intrinsic semiconductor to allow non-rectifying interconnection of, and electrical accessing of device regions is also disclosed. Insulator effected low leakage current device geometries and fabrication procedures therefore are taught. Selective electrical interconnection of drain to drain, source to drain, or source to source, of N-channel and/or P-channel Schottky barrier (MOSFET) devices formed on P-type, N-type and Intrinsic semiconductor allows realization of Schottky Barrier (CMOS), (MOSFET) with (MOSFET) load, balanced differential (MOSFET) device systems and inverting and non-inverting single devices with operating characteristics similar to (CMOS), which devices can be utilized in modulation, as well as in voltage controlled switching and effecting a direction of rectification. 89 figs.

  18. On the porosity of barrier layers

    Directory of Open Access Journals (Sweden)

    J. Mignot

    2009-09-01

    Full Text Available Barrier layers are defined as the layer between the pycnocline and the thermocline when the latter are different as a result of salinity stratification. We present a revisited 2-degree resolution global climatology of monthly mean oceanic Barrier Layer (BL thickness first proposed by de Boyer Montégut et al. (2007. In addition to using an extended data set, we present a modified computation method that addresses the observed porosity of BLs. We name porosity the fact that barrier layers distribution can, in some areas, be very uneven regarding the space and time scales that are considered. This implies an intermittent alteration of air-sea exchanges by the BL. Therefore, it may have important consequences for the climatic impact of BLs. Differences between the two computation methods are small for robust BLs that are formed by large-scale processes. However, the former approach can significantly underestimate the thickness of short and/or localized barrier layers. This is especially the case for barrier layers formed by mesoscale mechanisms (under the intertropical convergence zone for example and along western boundary currents and equatorward of the sea surface salinity subtropical maxima. Complete characterisation of regional BL dynamics therefore requires a description of the robustness of BL distribution to assess the overall impact of BLs on the process of heat exchange between the ocean interior and the atmosphere.

  19. Psychological Barriers to Behavior Change: How to indentify the barriers that inhibit change

    OpenAIRE

    Olson, James M.

    1992-01-01

    Adopting a healthy lifestyle often requires changing patterns of behavior. This article describes three categories of psychological barriers to behavior change: those that prevent the admission of a problem, those that interfere with initial attempts to change behavior, and those that make long-term change difficult. Strategies are identified that family physicians can use to overcome the barriers.

  20. Devices for overcoming biological barriers: the use of physical forces to disrupt the barriers.

    Science.gov (United States)

    Mitragotri, Samir

    2013-01-01

    Overcoming biological barriers including skin, mucosal membranes, blood brain barrier as well as cell and nuclear membrane constitutes a key hurdle in the field of drug delivery. While these barriers serve the natural protective function in the body, they limit delivery of drugs into the body. A variety of methods have been developed to overcome these barriers including formulations, targeting peptides and device-based technologies. This review focuses on the use of physical methods including acoustic devices, electric devices, high-pressure devices, microneedles and optical devices for disrupting various barriers in the body including skin and other membranes. A summary of the working principles of these devices and their ability to enhance drug delivery is presented. Copyright © 2012. Published by Elsevier B.V.

  1. SOME OBSERVATIONS ON THE DESIGN OF NOISE BARRIERS

    OpenAIRE

    Arkadiusz BOCZKOWSKI

    2013-01-01

    The issue connected with effectiveness of noise barriers has been the subject of numerous considerations among acousticians. On the one hand, noise barriers are still the most popular and the most frequently used protection against traffic noise, on the other hand, however, the excessive number of noise barriers and the results of research focusing on effectiveness of the existing barriers make us reflect whether it is reasonable to use them. Very often low effectiveness of noise barriers is ...

  2. Barrier performance researches for the safety evaluation

    International Nuclear Information System (INIS)

    Niibori, Yuichi

    2004-01-01

    So far, many researches were conducted to propose a scientific evidence (a safety case) for the realization of geological disposal in Japan. In order to regulate the geological disposal system of radioactive wastes, on the other hand, we need also a holistic approach to integrate various data related for the performance evaluations of the engineered barrier system and the natural barrier system. However, the scientific bases are not sufficient to establish the safety regulation for such a natural system. For example, we often apply the specific probability density function (PDF) to the uncertainty of barrier system due to the essential heterogeneity. However, the applicability is not clear in the regulation point of view. A viewpoint to understand such an applicability of PDFs has been presented. (author)

  3. Membrane barriers for radon gas flow restrictions

    International Nuclear Information System (INIS)

    Archibald, J.F.

    1984-08-01

    Research was performed to assess the feasibility of barrier membrane substances, for use within mining or associated high risk environments, in restricting the diffusion transport of radon gas quantities. Specific tests were conducted to determine permeability parameters of a variety of membrane materials with reference to radon flow capabilities. Tests were conducted both within laboratory and in-situ emanation environments where concentrations and diffusion flows of radon gas were known to exist. Equilibrium radon gas concentrations were monitored in initially radon-free chambers adjacent to gas sources, but separated by specified membrane substances. Membrane barrier effectiveness was demonstrated to result in reduced emanation concentrations of radon gas within the sampling chamber atmosphere. Minimum gas concentrations were evidenced where the barrier membrane material was shown to exhibit lowest radon permeability characteristics

  4. Efficient sound barrier calculations with the BEM

    DEFF Research Database (Denmark)

    Juhl, Peter Møller; Cutanda Henriquez, Vicente

    2018-01-01

    The Boundary Element Method has been used for calculating the effect of introducing sound barriers for some decades. The method has also been used for optimizing the shape of the barrier and in some cases the effects of introducing sound absorption. However, numerical calculations are still quite...... time consuming and inconvenient to use, which is limiting their use for many practical problems. Moreover, measurements are mostly taken in one-third or full octave bands opposed to the numerical computations at specific frequencies, which then has to be conducted using a fine density in frequencies....... This paper addresses some of the challenges and possible solutions for developing BEM into a more efficient tool for sound barrier calculations....

  5. Barriers to Medicaid Participation among Florida Dentists

    Science.gov (United States)

    Logan, Henrietta L.; Catalanotto, Frank; Guo, Yi; Marks, John; Dharamsi, Shafik

    2015-01-01

    Background Finding dentists who treat Medicaid-enrolled children is a struggle for many parents. The purpose of this study was to identify non-reimbursement factors that influence the decision by dentists about whether or not to participate in the Medicaid program in Florida. Methods Data from a mailed survey was analyzed using a logistic regression model to test the association of Medicaid participation with the Perceived Barriers and Social Responsibility variables. Results General and pediatric dentists (n=882) who identified themselves as either Medicaid (14%) or Non-Medicaid (86%) participants responded. Five items emerged as significant predictors of Medicaid participation, with a final concordance index of 0.905. Two previously unreported barriers to participation in Medicaid emerged: 1) dentists’ perception of social stigma from other dentists for participating in Medicaid, and 2) the lack of specialists to whom Medicaid patients can be referred. Conclusions This study provides new information about non-reimbursement barriers to Medicaid participation. PMID:25702734

  6. Phonon tunneling through a double barrier system

    International Nuclear Information System (INIS)

    Villegas, Diosdado; León-Pérez, Fernando de; Pérez-Álvarez, R.; Arriaga, J.

    2015-01-01

    The tunneling of optical and acoustic phonons at normal incidence on a double-barrier is studied in this paper. Transmission coefficients and resonance conditions are derived theoretically under the assumption that the long-wavelength approximation is valid. It is shown that the behavior of the transmission coefficients for the symmetric double barrier has a Lorentzian form close to resonant frequencies and that Breit–Wigner's formula have a general validity in one-dimensional phonon tunneling. Authors also study the so-called generalized Hartman effect in the tunneling of long-wavelength phonons and show that this effect is a numerical artifact resulting from taking the opaque limit before exploring the variation with a finite barrier width. This study could be useful for the design of acoustic devices

  7. Constructing bottom barriers with met grouting

    International Nuclear Information System (INIS)

    Shibazaki, M.; Yoshida, H.

    1997-01-01

    Installing a bottom barrier using conventional high pressure jetting technology and ensuring barrier continuity is challenging. This paper describes technology that has been developed and demonstrated for the emplacement of bottom barriers using pressures and flow rates above the conventional high pressure jetting parameters. The innovation capable of creating an improved body exceeding 5 meters in diameter has resulted in the satisfying connection and adherence between the treated columns. Besides, the interfaces among the improved bodies obtain the same strength and permeability lower than 1 x 10 -7 cm/sec as body itself. A wide variety of the thickness and the diameter of the improved mass optimizes the application, and the method is nearing completion. The paper explains an aspect and briefs case histories

  8. Epidermal Growth Factor and Intestinal Barrier Function

    Directory of Open Access Journals (Sweden)

    Xiaopeng Tang

    2016-01-01

    Full Text Available Epidermal growth factor (EGF is a 53-amino acid peptide that plays an important role in regulating cell growth, survival, migration, apoptosis, proliferation, and differentiation. In addition, EGF has been established to be an effective intestinal regulator helping to protect intestinal barrier integrity, which was essential for the absorption of nutrients and health in humans and animals. Several researches have demonstrated that EGF via binding to the EGF receptor and subsequent activation of Ras/MAPK, PI3K/AKT, PLC-γ/PKC, and STATS signal pathways regulates intestinal barrier function. In this review, the relationship between epidermal growth factor and intestinal development and intestinal barrier is described, to provide a better understanding of the effects of EGF on intestine development and health.

  9. Barriers To Successful Implementation of STEM Education

    Directory of Open Access Journals (Sweden)

    James A. Ejiwale

    2013-05-01

    Full Text Available The implementation of STEM education in schools across the globe is to prepare the future workforce with strong scientific and mathematical backgrounds to enhance skills development across STEM disciplines. However, for STEM education to achieve its goals and objectives, addressing the barriers to STEM education should start by fixing the problems at the elementary, junior and senior high school levels; the grassroots and potential feeders to colleges and universities. Since many nations including the United States of America is in dire need of the workforce with adequate preparation in science and mathematics to help address the nation’s economy that is in shambles, the barriers to its successful implementation should be identified and addressed. In this paper, (a the definition of STEM education and (b some barriers to successful implementation of STEM education are discussed and elaborated.

  10. Barriers to student success in engineering education

    Science.gov (United States)

    Boles, Wageeh; Whelan, Karen

    2017-07-01

    In the UK, the USA and Australia, there have been calls for an increase in the number of engineering graduates to meet the needs of current global challenges. Universities around the world have been grappling with how to both attract more engineering students and to then retain them. Attrition from engineering programmes is disturbingly high. This paper reports on an element of research undertaken through an Australian Learning and Teaching Council-funded Fellowship that investigated the factors leading to student attrition in engineering programmes, by identifying barriers to student success. Here, we contrast a review of the literature related to student barriers and success with student perceptions, gathered through a series of focus groups and interviews at three Australian universities. We also present recommendations for action to try to remove barriers to student success.

  11. Compositional Safety Analysis using Barrier Certificates

    DEFF Research Database (Denmark)

    Sloth, Christoffer; Pappas, George J.; Wisniewski, Rafael

    2012-01-01

    This paper proposes a compositional method for verifying the safety of a dynamical system, given as an interconnection of subsystems. The safety verification is conducted by the use of the barrier certificate method; hence, the contribution of this paper is to show how to obtain compositional...... conditions for safety verification. We show how to formulate the verification problem, as a composition of coupled subproblems, each given for one subsystem. Furthermore, we show how to find the compositional barrier certificates via linear and sum of squares programming problems. The proposed method makes...... it possible to verify the safety of higher dimensional systems, than the method for centrally computed barrier certificates. This is demonstrated by verifying the safety of an emergency shutdown of a wind turbine....

  12. Phonon tunneling through a double barrier system

    Energy Technology Data Exchange (ETDEWEB)

    Villegas, Diosdado [Departamento de Física, Universidad Central “Marta Abreu” de Las Villas, CP 54830, Santa Clara, Villa Clara (Cuba); Instituto de Física, Universidad Autónoma de Puebla, 18 Sur y San Claudio, Edif. 110A, Ciudad Universitaria, 72570 Puebla (Mexico); León-Pérez, Fernando de [Centro Universitario de la Defensa de Zaragoza, Ctra. de Huesca s/n, E-50090 Zaragoza (Spain); Pérez-Álvarez, R. [Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, CP 62209 Cuernavaca (Mexico); Arriaga, J., E-mail: arriaga@ifuap.buap.mx [Instituto de Física, Universidad Autónoma de Puebla, 18 Sur y San Claudio, Edif. 110A, Ciudad Universitaria, 72570 Puebla (Mexico)

    2015-04-15

    The tunneling of optical and acoustic phonons at normal incidence on a double-barrier is studied in this paper. Transmission coefficients and resonance conditions are derived theoretically under the assumption that the long-wavelength approximation is valid. It is shown that the behavior of the transmission coefficients for the symmetric double barrier has a Lorentzian form close to resonant frequencies and that Breit–Wigner's formula have a general validity in one-dimensional phonon tunneling. Authors also study the so-called generalized Hartman effect in the tunneling of long-wavelength phonons and show that this effect is a numerical artifact resulting from taking the opaque limit before exploring the variation with a finite barrier width. This study could be useful for the design of acoustic devices.

  13. Surface barrier research at the Hanford Site

    International Nuclear Information System (INIS)

    Gee, G.W.; Ward, A.L.; Fayer, M.J.

    1997-01-01

    At the DOE Hanford Site, a field-scale prototype surface barrier was constructed in 1994 over an existing waste site as a part of a CERCLA treatability test. The above-grade barrier consists of a fine-soil layer overlying coarse layers of sands, gravels, basalt rock (riprap), and a low permeability asphalt layer. Two sideslope configurations, clean-fill gravel on a 10:1 slope and basalt riprap on a 2:1 slope, were built and are being tested. Design considerations included: constructability; drainage and water balance monitoring, wind and water erosion control and monitoring; surface revegetation and biotic intrusion; subsidence and sideslope stability, and durability of the asphalt layer. The barrier is currently in the final year of a three-year test designed to answer specific questions related to stability and long-term performance. One half of the barrier is irrigated such that the total water applied, including precipitation, is 480 mm/yr (three times the long-term annual average). Each year for the past two years, an extreme precipitation event (71 mm in 8 hr) representing a 1,000-yr return storm was applied in late March, when soil water storage was at a maximum. While the protective sideslopes have drained significant amounts of water, the soil cover (2-m of silt-loam soil overlying coarse sand and rock) has never drained. During the past year there was no measurable surface runoff or wind erosion. This is attributed to extensive revegetation of the surface. In addition, the barrier elevation has shown a small increase of 2 to 3 cm that is attributed to a combination of root proliferation and freeze/thaw activity. Testing will continue through September 1997. Performance data from the prototype barrier will be used by DOE in site-closure decisions at Hanford

  14. Tritium permeation barriers for fusion technology

    International Nuclear Information System (INIS)

    Perujo, A.; Forcey, K.

    1994-01-01

    An important issue concerning the safety, feasibility and fueling (i.e., tritium breeding ratio and recovery from the breeding blanket) of a fusion reactor is the possible tritium leakages through the structural materials and in particular through those operating at high temperatures. The control of tritium permeation could be a critical factor in determining the viability of a future fusion power reactor. The formation of tritium permeation barriers to prevent the loss of tritium to the coolant by diffusion though the structural material seems to be the most practical method to minimize such losses. Many authors have discussed the formation of permeation barriers to reduce the leakage of hydrogen isotopes through proposed first wall and structural materials. In general, there are two routes for the formation of such a barrier, namely: the growth of oxide layers (e.g., Cr 2 O 3 , Al 2 O 3 , etc.) or the application of surface coatings. Non-metals are the most promising materials from the point of view of the formation of permeation barriers. Oxides such as Al 2 O 3 or Cr 2 O 3 or carbides such as SiC or TiC have been proposed. Amongst the metals only tungsten or gold are sufficiently less permeable than steel to warrant investigation as candidate materials for permeation barriers. It is of course possible to grow oxide layers on steel directly by heating in the atmosphere or under a variety of conditions (first route above). The direct oxidizing is normally done in an environment of open-quotes wet hydrogenclose quotes to promote the growth of chromia on, for example, nickel steels or ternary oxides on 316L to prevent corrosion. The application of surface layers (second route above), offers a greater range of materials for the formation of permeation barriers. In addition to reducing permeation, such layers should be adhesive, resistant to attack by corrosive breeder materials and should not crack during thermal cycling

  15. Barriers to evidence-based medicine: a systematic review.

    Science.gov (United States)

    Sadeghi-Bazargani, Homayoun; Tabrizi, Jafar Sadegh; Azami-Aghdash, Saber

    2014-12-01

    Evidence-based medicine (EBM) has emerged as an effective strategy to improve health care quality. The aim of this study was to systematically review and carry out an analysis on the barriers to EBM. Different database searching methods and also manual search were employed in this study using the search words ('evidence-based' or 'evidence-based medicine' or 'evidence-based practice' or 'evidence-based guidelines' or 'research utilization') and (barrier* or challenge or hinder) in the following databases: PubMed, Scopus, Web of Knowledge, Cochrane library, Pro Quest, Magiran, SID. Out of 2592 articles, 106 articles were finally identified for study. Research barriers, lack of resources, lack of time, inadequate skills, and inadequate access, lack of knowledge and financial barriers were found to be the most common barriers to EBM. Examples of these barriers were found in primary care, hospital/specialist care, rehabilitation care, medical education, management and decision making. The most common barriers to research utilization were research barriers, cooperation barriers and changing barriers. Lack of resources was the most common barrier to implementation of guidelines. The result of this study shows that there are many barriers to the implementation and use of EBM. Identifying barriers is just the first step to removing barriers to the use of EBM. Extra resources will be needed if these barriers are to be tackled. © 2014 John Wiley & Sons, Ltd.

  16. Message maps for safety barrier awareness

    DEFF Research Database (Denmark)

    Jørgensen, Kirsten; Duijm, Nijs Jan; Troen, Hanne

    2011-01-01

    , time, or place, and by enabling them to observe and judge whether the relevant safety barriers are in place and in good order. This can be considered “Situational Awareness” (SA), which is an essential competence enabling an employee to perform his/her job safely. This SA entails a number...... of requirements for people, work conditions, management, learning, knowledge, experience, motivation etc. The Dutch WORM and RAM projects led to the identification of 64 types of risks and the safety barriers and performance factors linked to these risks. The Danish DanWORM project has transferred this knowledge...

  17. Message maps for Safety Barrier Awareness

    DEFF Research Database (Denmark)

    of the risks in a given situation, time or place, and by enabling them to observe and judge whether the relevant safety barriers are in place and in good order. This can be considered as “Situational Awareness (SA)”, which is an essential competence for at en employee can perform his/her job safely....... This Situational Awareness puts a number of requirements on people, work conditions, management, learning, knowledge, experience, motivation, etc. The Dutch WORM and RAM projects led to the identification of 64 types of risks and the safety barriers and performance factors that are linked to these risks...

  18. THE BARRIERS OF IMPLEMENTING E-PROCUREMENT

    Directory of Open Access Journals (Sweden)

    Corina Pop Sitar

    2011-01-01

    Full Text Available The concept of e-procurement has many different meanings ranging from shopping on theinternet (through reverse auction to collaborative initiatives taking place in virtualmeetings. There are many forms of e-procurement that can be found in the literature. In thispaper we define the most important forms of e-procurement. Next, we present the mainbarriers of implementing an e-procurement found in the literature. Furthermore, we presenta matrix with the main barriers of e-procurement classified in four main categories. Finally,we elaborated for managers some guidelines in order to overcome the barriers ofimplementing e-procurement.

  19. Electrochemical cell structure including an ionomeric barrier

    Science.gov (United States)

    Lambert, Timothy N.; Hibbs, Michael

    2017-06-20

    An apparatus includes an electrochemical half-cell comprising: an electrolyte, an anode; and an ionomeric barrier positioned between the electrolyte and the anode. The anode may comprise a multi-electron vanadium phosphorous alloy, such as VP.sub.x, wherein x is 1-5. The electrochemical half-cell is configured to oxidize the vanadium and phosphorous alloy to release electrons. A method of mitigating corrosion in an electrochemical cell includes disposing an ionomeric barrier in a path of electrolyte or ion flow to an anode and mitigating anion accumulation on the surface of the anode.

  20. Relativistic tunneling through two successive barriers

    International Nuclear Information System (INIS)

    Lunardi, Jose T.; Manzoni, Luiz A.

    2007-01-01

    We study the relativistic quantum mechanical problem of a Dirac particle tunneling through two successive electrostatic barriers. Our aim is to study the emergence of the so-called generalized Hartman effect, an effect observed in the context of nonrelativistic tunneling as well as in its counterparts and which is often associated with the possibility of superluminal velocities in the tunneling process. We discuss the behavior of both the phase (or group) tunneling time and the dwell time, and show that in the limit of opaque barriers the relativistic theory also allows the emergence of the generalized Hartman effect. We compare our results with the nonrelativistic ones and discuss their interpretation

  1. Dielectric barrier discharge image processing by Photoshop

    Science.gov (United States)

    Dong, Lifang; Li, Xuechen; Yin, Zengqian; Zhang, Qingli

    2001-09-01

    In this paper, the filamentary pattern of dielectric barrier discharge has been processed by using Photoshop, the coordinates of each filament can also be obtained. By using Photoshop two different ways have been used to analyze the spatial order of the pattern formation in dielectric barrier discharge. The results show that the distance of the neighbor filaments at U equals 14 kV and d equals 0.9 mm is about 1.8 mm. In the scope of the experimental error, the results from the two different methods are similar.

  2. Barrier design for tornado-generated missiles

    International Nuclear Information System (INIS)

    Kar, A.K.

    1977-01-01

    Nuclear power plant facilities and many other structures need protection against missiles generated by tornados and explosions. The missile impacts result in both local and overall effects on barriers or targets. The local effects are characterized by penetration, perforation and backface spalling or scabbing of the target material. The overall effects of missile impact on structural stability are commonly evaluated in terms of the flexural and shear behaviour of the target. Empirical formulas are presented to determine the local effects on concrete and steel barriers. Procedures are given for determining the design loads for overall effects. Design methods are described. (Auth.)

  3. Barrier design for tornado-generated missiles

    International Nuclear Information System (INIS)

    Kar, A.K.

    1977-01-01

    Nuclear powerplant facilities and many other structures need protection against missiles generated by tornadoes and explosions. The missile impacts result in both local and overall effects on barriers or targets. The local effects are characterized by penetration, perforation, and backface spalling or scabbing of the target material. The overall effects of missile impact on structural stability are commonly evaluated in terms of the flexural and shear behavior of the target. Empirical formulas are presented to determine the local effects on concrete and steel barriers. Procedures are given for determining the design loads for overall effects. Design methods are described

  4. Testing the psychological barrier in borsa Istanbul

    OpenAIRE

    Çinko, Murat

    2014-01-01

    The aim of the study is to find out the existence of “psychological barriers” in Borsa Istanbul. The importance of this study is that Psychological Barrier has never been tested in Borsa Istanbul. The data set consists of 2523 daily closing index values between 03 April 2003 to 12 April 2013. The reason of choosing these dates is that all index values have five digits. Chi - Square goodness of fit test and regression analysis indicate that there exists a psychological barrier at thousands lev...

  5. Cross-cultural barriers to health care.

    Science.gov (United States)

    Vidaeff, Alex C; Kerrigan, Anthony J; Monga, Manju

    2015-01-01

    Culturally sensitive health care represents a real ethical and practical need in a Western healthcare system increasingly serving a multiethnic society. This review focuses on cross-cultural barriers to health care and incongruent aspects from a cultural perspective in the provision of health care. To overcome difficulties in culturally dissimilar interactions and eventually remove cross-cultural barriers to health care, a culturally sensitive physician considers his or her own identity, values, and beliefs; recognizes the similarities and differences among cultures; understands what those similarities and differences mean; and is able to bridge the differences to accomplish clear and effective communication.

  6. LGBT Populations' Barriers to Cancer Care.

    Science.gov (United States)

    Boehmer, Ulrike

    2018-02-01

    To describe lesbian, gay, bisexual, and transgender (LGBT) individuals' barriers to accessing and receiving quality cancer care. Published data on cancer care and studies of LGBT individuals. There is a clustering of barriers among LGBT individuals, which suggests multiple inequities exist in LGBT individuals' cancer care, although data on disparities along the cancer control continuum are not consistently available. Nurses can make a difference in LGBT individuals' cancer care by obtaining training on LGBT health and their cancer-related needs and by providing a welcoming and respectful relationship with LGBT patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Developments in permeable and low permeability barriers

    International Nuclear Information System (INIS)

    Jefferis, S.A.; Norris, G.H.; Thomas, A.O.

    1997-01-01

    The concept of the reactive treatment zone whereby pollutants are attenuated as they move along a pathway in the ground has enabled a re-thinking of many of the concepts of containment. In particular it offers the potential for the control of the flux from a contaminated area by controlling the contaminant concentration in the pathway(s) as well as or instead of using a low permeability barrier. The paper outlines the basic concepts of the reactive treatment zone and the use of permeable and low permeability reactive systems. The paper then gives a case history of the installation of a permeable barrier using an in-situ reaction chamber

  8. Fusion barrier distributions and fission anisotropies

    International Nuclear Information System (INIS)

    Hinde, D.J.; Morton, C.R.; Dasgupta, M.; Leigh, J.R.; Lestone, J.P.; Lemmon, R.C.; Mein, J.C.; Newton, J.O.; Timmers, H.; Rowley, N.; Kruppa, A.T.

    1995-01-01

    Fusion excitation functions for 16,17 O+ 144 Sm have been measured to high precision. The extracted fusion barrier distributions show a double-peaked structure interpreted in terms of coupling to inelastic collective excitations of the target. The effect of the positive Q-value neutron stripping channel is evident in the reaction with 17 O. Fission and evaporation residue cross-sections and excitation functions have been measured for the reaction of 16 O+ 208 Pb and the fusion barrier distribution and fission anisotropies determined. It is found that the moments of the fusion l-distribution determined from the fusion and fission measurements are in good agreement. ((orig.))

  9. Vehicle barriers: emphasis on natural features

    International Nuclear Information System (INIS)

    Adams, K.G.; Roscoe, B.J.

    1985-07-01

    The recent increase in the use of car and truck bombs by terrorist organizations has led NRC to evaluate the adequacy of licensee security against such threats. As part of this evaluation, one of the factors is the effectiveness of terrain and vegetation in providing barriers against the vehicle entry. The effectiveness of natural features is presented in two contexts. First, certain natural features are presented. Second, the effectiveness of combinations of features is presented. In addition to the discussion of natural features, this report provides a discussion of methods to slow vehicles. Also included is an overview of man-made barrier systems, with particular attention to ditches. 17 refs., 49 figs

  10. Permanent isolation surface barrier: Functional performance

    International Nuclear Information System (INIS)

    Wing, N.R.

    1993-10-01

    This document presents the functional performance parameters for permanent isolation surface barriers. Permanent isolation surface barriers have been proposed for use at the Hanford Site (and elsewhere) to isolate and dispose of certain types of waste in place. Much of the waste that would be disposed of using in-place isolation techniques is located in subsurface structures, such as solid waste burial grounds, tanks, vaults, and cribs. Unless protected in some way, the wastes could be transported to the accessible environment via transport pathways, such as water infiltration, biointrusion, wind and water erosion, human interference, and/or gaseous release

  11. Barrierer for ibrugtagning af videooptaget universitetsundervisning

    DEFF Research Database (Denmark)

    Rattleff, Pernille

    2009-01-01

    tilgængelige for studerende og andre interesserede. Der kan således iagttages nogle barrierer i forhold til ibrugtagning af videooptaget undervisning på universitetsniveau, idet underviserne for en umiddelbar betragtning tilsyneladende for det første har nogle forbehold af psykologisk, for det andet af...... begrebsafklaring, præsenterer forfatterne i denne artikel erfaringerne med tilbud af videostreamet og podcastet universitetsundervisning til studerende på Danmarks Pædagogiske Universitetsskole med henblik på en diskussion af de potentialer og især de barrierer, der kan iagttages i forhold til en mere systematisk...

  12. Self-regulation of turbulence bursts and transport barriers

    International Nuclear Information System (INIS)

    Floriani, E; Ciraolo, G; Ghendrih, Ph; Sarazin, Y; Lima, R

    2013-01-01

    The interplay between turbulent bursts and transport barriers is analyzed with a simplified model of interchange turbulence in magnetically confined plasmas. The turbulent bursts spread into the transport barriers and, depending on the competing magnitude of the burst and stopping capability of the barrier, can burn through. Simulations of two models of transport barriers are presented: a hard barrier where interchange turbulence modes are stable in a prescribed region and a soft barrier with external plasma biasing. The response of the transport barriers to the non-linear perturbations of the turbulent bursts, addressed in a predator–prey approach, indicates that the barriers monitor an amplification factor of the turbulent bursts, with amplification smaller than one for most bursts and, in some cases, amplification factors that can significantly exceed unity. The weak barriers in corrugated profiles and magnetic structures, as well as the standard barriers, are characterized by these transmission properties, which then regulate the turbulent burst transport properties. The interplays of barriers and turbulent bursts are modeled as competing stochastic processes. For different classes of the probability density function (PDF) of these processes, one can predict the heavy tail properties of the bursts downstream from the barrier, either exponential for a leaky barrier, or with power laws for a tight barrier. The intrinsic probing of the transport barriers by the turbulent bursts thus gives access to the properties of the barriers. The main stochastic variables are the barrier width and the spreading distance of the turbulent bursts within the barrier, together with their level of correlation. One finds that in the case of a barrier with volumetric losses, such as radiation or particle losses as addressed in our present simulations, the stochastic model predicts a leaky behavior with an exponential PDF of escaping turbulent bursts in agreement with the simulation

  13. Removing bridge barriers stimulates suicides: an unfortunate natural experiment.

    Science.gov (United States)

    Beautrais, Annette L; Gibb, Sheree J; Fergusson, David M; Horwood, L John; Larkin, Gregory Luke

    2009-06-01

    Safety barriers to prevent suicide by jumping were removed from Grafton Bridge in Auckland, New Zealand, in 1996 after having been in place for 60 years. This study compared the number of suicides due to jumping from the bridge after the reinstallation of safety barriers in 2003. National mortality data for suicide deaths were compared for three time periods: 1991-1995 (old barrier in place); 1997-2002 (no barriers in place); 2003-2006 (after barriers were reinstated). Removal of barriers was followed by a fivefold increase in the number and rate of suicides from the bridge. These increases led to a decision to reinstall safety barriers. Since the reinstallation of barriers, of an improved design, in 2003, there have been no suicides from the bridge. This natural experiment, using a powerful a-b-a (reversal) design, shows that safety barriers are effective in preventing suicide: their removal increases suicides; their reinstatement prevents suicides.

  14. Use of electrical barriers to deter movement of round goby

    Science.gov (United States)

    Savino, Jacqueline F.; Jude, David J.; Kostich, Melissa J.; Coutant, Charles C.

    2001-01-01

    An electrical barrier was chosen as a possible means to deter movement of round goby Neogobius melanostomus. Feasibility studies in a 2.1-m donut-shaped tank determined the electrical parameters necessary to inhibit round goby from crossing the 1-m stretch of the benthic, electrical barrier. Increasing electrical pulse duration and voltage increased effectiveness of the barrier in deterring round goby movement through the barrier. Differences in activity of round goby during daytime and nocturnal tests did not change the effectiveness of the barrier. In field verification studies, an electrical barrier was placed between two blocking nets in the Shiawassee River, Michigan. The barrier consisted of a 6-m wide canvas on which were laid four cables carrying the electrical current. Seven experiments were conducted, wherein 25 latex paint-marked round goby were introduced upstream of the electrical barrier and recovered 24 h later upstream, on, and downstream of the barrier. During control studies, round goby moved across the barrier within 20 min from release upstream. With the barrier on and using the prescribed electrical settings shown to inhibit passage in the laboratory, the only marked round goby found below the barrier were dead. At reduced pulse durations, a few round goby (mean one/test) were found alive, but debilitated, below the barrier. The electrical barrier could be incorporated as part of a program in reducing movement of adult round goby through artificial connections between watersheds.

  15. Deployment Efficiency and Barrier Effectiveness Testing of a Temporary Anti-Personnel (TAP) Barrier System.

    Energy Technology Data Exchange (ETDEWEB)

    Allen, David James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hedrick, Charles D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martinez, Ruben [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-02-01

    This report documents tests conducted by Sandia National Laboratories (SNL) on behalf of the U.S. Department of State to evaluate a temporary anti-personnel (TAP) barrier system developed by Mitigation Technologies. For this, the SNL Denial and Structural Assessment department developed a test protocol for the evaluation of the TAP barrier system on the basis of deployment efficiency and barrier effectiveness against a riotous/mob attack threat. The test protocol was then executed by SNL personnel and the results of the testing are documented.

  16. Photoelectric effect in surface-barrier structures

    International Nuclear Information System (INIS)

    Kononenko, V.K.; Tupenevich, P.A.

    1985-08-01

    Deviations from the Fowler law were observed when investigating photoelectric emission in p-type ZnTe surface-barrier structures. The revealed peculiarities of the structure photosensitivity spectrum are explained by the electron transitions involving surface states at the metal-semiconductor interface. (author)

  17. Homoepitaxial graphene tunnel barriers for spin transport

    Directory of Open Access Journals (Sweden)

    Adam L. Friedman

    2016-05-01

    Full Text Available Tunnel barriers are key elements for both charge-and spin-based electronics, offering devices with reduced power consumption and new paradigms for information processing. Such devices require mating dissimilar materials, raising issues of heteroepitaxy, interface stability, and electronic states that severely complicate fabrication and compromise performance. Graphene is the perfect tunnel barrier. It is an insulator out-of-plane, possesses a defect-free, linear habit, and is impervious to interdiffusion. Nonetheless, true tunneling between two stacked graphene layers is not possible in environmental conditions usable for electronics applications. However, two stacked graphene layers can be decoupled using chemical functionalization. Here, we demonstrate that hydrogenation or fluorination of graphene can be used to create a tunnel barrier. We demonstrate successful tunneling by measuring non-linear IV curves and a weakly temperature dependent zero-bias resistance. We demonstrate lateral transport of spin currents in non-local spin-valve structures, and determine spin lifetimes with the non-local Hanle effect. We compare the results for hydrogenated and fluorinated tunnel and we discuss the possibility that ferromagnetic moments in the hydrogenated graphene tunnel barrier affect the spin transport of our devices.

  18. Homoepitaxial graphene tunnel barriers for spin transport

    Science.gov (United States)

    Friedman, Adam L.; van't Erve, Olaf M. J.; Robinson, Jeremy T.; Whitener, Keith E.; Jonker, Berend T.

    2016-05-01

    Tunnel barriers are key elements for both charge-and spin-based electronics, offering devices with reduced power consumption and new paradigms for information processing. Such devices require mating dissimilar materials, raising issues of heteroepitaxy, interface stability, and electronic states that severely complicate fabrication and compromise performance. Graphene is the perfect tunnel barrier. It is an insulator out-of-plane, possesses a defect-free, linear habit, and is impervious to interdiffusion. Nonetheless, true tunneling between two stacked graphene layers is not possible in environmental conditions usable for electronics applications. However, two stacked graphene layers can be decoupled using chemical functionalization. Here, we demonstrate that hydrogenation or fluorination of graphene can be used to create a tunnel barrier. We demonstrate successful tunneling by measuring non-linear IV curves and a weakly temperature dependent zero-bias resistance. We demonstrate lateral transport of spin currents in non-local spin-valve structures, and determine spin lifetimes with the non-local Hanle effect. We compare the results for hydrogenated and fluorinated tunnel and we discuss the possibility that ferromagnetic moments in the hydrogenated graphene tunnel barrier affect the spin transport of our devices.

  19. Barriers to Teaching Introductory Physical Geography Online

    Science.gov (United States)

    Ritter, Michael E.

    2012-01-01

    Learning geography online is becoming an option for more students but not without controversy. Issues of faculty resources, logistics, professional recognition, and pedagogical concerns are cited as barriers to teaching online. Offering introductory physical geography online presents special challenges. As a general education course, an…

  20. Thinly disguised contempt: a barrier to excellence.

    Science.gov (United States)

    Brown-Stewart, P

    1987-04-01

    Many elements in contemporary leadership and management convey contempt for employees. "Thinly disguised contempt," a concept introduced by Peters and Austin in A Passion For Excellence, explains many barriers to the achievement of excellence in corporations across disciplines. Health care executives and managers can learn from the errors of corporate management and avoid replicating these errors in the health care industry.

  1. Reconnaissance level study Mississippi storm surge barrier

    NARCIS (Netherlands)

    Van Ledden, M.; Lansen, A.J.; De Ridder, H.A.J.; Edge, B.

    2012-01-01

    This paper reports a reconnaissance level study of a storm surge barrier in the Mississippi River. Historical hurricanes have shown storm surge of several meters along the Mississippi River levees up to and upstream of New Orleans. Future changes due to sea level rise and subsidence will further

  2. Kiwifruit, mucins, and the gut barrier.

    Science.gov (United States)

    Moughan, Paul J; Rutherfurd, Shane M; Balan, Prabhu

    2013-01-01

    Kiwifruit has long been regarded in China, where it originated from, for its health properties and particularly in relation to digestion and general gut health. There are a number of physical and chemical properties of the fruit, including its dietary fiber content, the presence of raphides, its high water holding capacity and actinidin content, that suggest that kiwifruit may be effective in influencing gut mucin production and thus enhancing the integrity of the gut barrier. The mucous layer, which comprises mucins and other materials, overlying the mucosal epithelium, is an important component of the gut barrier. The gut barrier plays a crucial role in separating the host from the often noxious external environment. The mucous layer, which covers the entire gastrointestinal tract (GIT), is the front line of innate host defense. There have been few direct studies of the effect of kiwifruit ingestion on mucin production in the GIT, and findings that are available using animal models are somewhat inconsistent. Taking results for digesta mucin content, number of goblet cells, and mucin gene expression, together, it would seem that green kiwifruit and possibly gold kiwifruit do influence gut mucin production, and the kiwifruit as part of a balanced diet may help to maintain the mucous layer and gut barrier. More corroborative experimental evidence is needed, and studies need to be undertaken in humans. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Telehomecare in The Netherlands: Barriers to implementation

    NARCIS (Netherlands)

    HSM Kort; Joost van Hoof

    2012-01-01

    Telehomecare is one of the technological solutions used by older persons to remain living at home in their own community. A selection of 85 Dutch telehomecare projects was examined in terms of the barriers to their implementation. Three categories of telehomecare technologies were distinguished: (i)

  4. Telehomecare in the Netherlands : barriers to implementation

    NARCIS (Netherlands)

    Kort, H.S.M.; Hoof, van J.

    2012-01-01

    Telehomecare is one of the technological solutions used by older persons to remain living at home in their own community. A selection of 85 Dutch telehomecare projects was examined in terms of the barriers to their implementation. Three categories of telehomecare technologies were distinguished: (i)

  5. Double-barrier junction based dc SQUID

    NARCIS (Netherlands)

    Bartolomé, M.E.; Brinkman, Alexander; Flokstra, Jakob; Golubov, Alexandre Avraamovitch; Rogalla, Horst

    2000-01-01

    dc SQUIDs based on double-barrier Nb/Al/AlOx/Al/AlOx/Al/Nb junctions (DBSQs) have been fabricated and tested for the first time. The current–voltage curves have been measured at temperatures down to 1.4 K. The critical current, Ic, dependence on the temperature T is partially described by the

  6. On Emotional Barriers to Second Language Learning

    Institute of Scientific and Technical Information of China (English)

    Chen Qin

    2012-01-01

    Language learning is a very complex process, which is related to many factors, either internal or external. Affective factors plays an important role in a second language learning. If only we realize such affective factors, we can overcome the emotional barriers effectively and have a successful learning.

  7. BSN completion barriers, challenges, incentives, and strategies.

    Science.gov (United States)

    Duffy, Marie T; Friesen, Mary Ann; Speroni, Karen Gabel; Swengros, Diane; Shanks, Laura A; Waiter, Pamela A; Sheridan, Michael J

    2014-04-01

    The objectives of this study were to explore RN perceptions regarding barriers/challenges and incentives/supports for BSN completion and identify recommendations to increase RN BSN completion. The Institute of Medicine's 2011 The Future of Nursing report recommended the proportion of RNs with a BSN increase to 80% by 2020. This qualitative study included 41 RNs who participated in 1 of 6 focus groups based on their BSN completion status. Primary themes were sacrifices, barriers/challenges, incentives/supports, value, how to begin, and pressure. Primary BSN completion barriers/challenges were work-life balance and economic issues. Incentives/supports identified were financial compensation, assistance from employer and academic institution, and encouragement from family. Institutional strategies recommended for increasing BSN completion rates were improved access to education and financial support facilitated by collaboration between hospitals and academic institutions. Exploring RN barriers/challenges and incentives/supports for BSN completion can lead to implementation of institutional strategies, such as tuition reimbursement and academic collaboration.

  8. Intestinal barrier integrity and inflammatory bowel disease

    DEFF Research Database (Denmark)

    Holmberg, Fredrik Eric Olof; Pedersen, Jannie; Jørgensen, Peter

    2018-01-01

    Disruption of normal barrier function is a fundamental factor in the pathogenesis of inflammatory bowel disease, which includes increased epithelial cell death, modified mucus configuration, altered expression and distribution of tight junction-proteins, along with a decreased expression of antim......Disruption of normal barrier function is a fundamental factor in the pathogenesis of inflammatory bowel disease, which includes increased epithelial cell death, modified mucus configuration, altered expression and distribution of tight junction-proteins, along with a decreased expression...... of antimicrobial peptides. Inflammatory bowel disease is associated with life-long morbidity for affected patients, and both the incidence and prevalence is increasing globally, resulting in substantial economic strain for society. Mucosal healing and re-establishment of barrier integrity is associated......, novel treatment strategies to accomplish mucosal healing and to re-establish normal barrier integrity in inflammatory bowel disease are warranted, and luminal stem cell-based approaches might have an intriguing potential. Transplantation of in vitro expanded intestinal epithelial stem cells derived...

  9. Open problems in sub-barrier fusion

    International Nuclear Information System (INIS)

    Vandenbosch, R.

    1992-01-01

    Two aspects of sub-barrier fusion are discussed. A challenge to the use of fission fragment angular distributions to probe the spin distribution in fusion is addressed. Evidence from excitation functions for the importance of neutron transfer and the neck degree of freedom is examined

  10. Impenetrable Barriers in Phase-Space

    International Nuclear Information System (INIS)

    Wiggins, S.; Wiesenfeld, L.; Jaffe, C.; Uzer, T.

    2001-01-01

    Dynamical systems theory is used to construct a general phase-space version of transition state theory. Special multidimensional separatrices are found which act as impenetrable barriers in phase-space between reacting and nonreacting trajectories. The elusive momentum-dependent transition state between reactants and products is thereby characterized. A practical algorithm is presented and applied to a strongly coupled Hamiltonian

  11. The Barrier within: Relational Aggression among Women

    Science.gov (United States)

    Brock, Barbara L.

    2010-01-01

    Relational aggression among women presents an overlooked barrier to women's quest for advancement in the workplace. Although research on women's leadership extols their ability to collaborate and form lasting, supportive relationships, one cannot assume that all women are supportive of other women. Research reveals that relational aggression,…

  12. Dielectric barrier discharges applied for optical spectrometry

    Czech Academy of Sciences Publication Activity Database

    Brandt, S.; Schütz, A.; Klute, F. D.; Kratzer, Jan; Franzke, J.

    2016-01-01

    Roč. 123, SEP (2016), s. 6-32 ISSN 0584-8547 R&D Projects: GA ČR GA14-23532S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * analytical spectroscopy * applications Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 3.241, year: 2016

  13. Tandem mirror reactor with thermal barriers

    International Nuclear Information System (INIS)

    Carlson, G.A.; Arfin, B.; Barr, W.L.; Boghosian, B.M.; Erickson, J.L.; Fink, J.H.; Hamilton, G.W.; Logan, B.G.; Myall, J.O.; Neef, W.S. Jr.

    1979-01-01

    This report gives detailed information in the form of the following chapters: (1) overview, (2) plasma physics, (3) magnets, (4) end-plug neutral beams, (5) barrier pump neutral beams, (6) ecr heating, (7) plasma direct converter, and (8) central cell

  14. Barriers to Professional Advancement among Female Managers.

    Science.gov (United States)

    O'Leary, Virginia E.

    It appears that there is nothing inherently associated with femaleness which should preclude the ascendence of women into management positions. However, barriers do exist and they stem from such factors as societal sex-role stereotypes, attitudes toward women in management, attitudes toward female competence, and the prevalence of the male…

  15. Tacit Knowledge Barriers in Franchising: Practical Solutions

    Science.gov (United States)

    Cumberland, Denise; Githens, Rod

    2012-01-01

    Purpose: The purpose of this paper is to identify barriers that hinder tacit knowledge transfer in a franchise environment and offer a compendium of solutions that encourage franchisees and franchisors to leverage tacit knowledge as a resource for competitive advantage. Design/methodology/approach: Drawing from the research on franchise…

  16. Tacit Knowledge Barriers within Franchise Organizations

    Science.gov (United States)

    Cumberland, Denise M.; Githens, Rod P.

    2010-01-01

    This paper reviews knowledge management in the context of a franchise business operation, with a focus on tacit knowledge barriers. In a franchise organization, the transfer of knowledge occurs on multiple levels and has an added level of complexity because of the number of partners and relationships. Tacit knowledge transfer should occur…

  17. Computer simulations of the random barrier model

    DEFF Research Database (Denmark)

    Schrøder, Thomas; Dyre, Jeppe

    2002-01-01

    A brief review of experimental facts regarding ac electronic and ionic conduction in disordered solids is given followed by a discussion of what is perhaps the simplest realistic model, the random barrier model (symmetric hopping model). Results from large scale computer simulations are presented...

  18. Improved Metallography Of Thermal-Barrier Coatings

    Science.gov (United States)

    Brindley, William J.; Leonhardt, Todd A.

    1991-01-01

    New technique for preparation of metallographic samples makes interpretation of images of pores and microcracks more reliable. Involves use of vacuum epoxy infiltration and interference-film coating to reduce uncertainty. Developed for inspection of plasma-sprayed ceramic thermal-barrier coatings on metals but applicable to other porous, translucent materials, including many important ceramics.

  19. Language Barriers of the Culturally Different.

    Science.gov (United States)

    Berg, Paul Conrad

    Language differences peculiar to the disadvantaged are discussed as they relate to reading. Linguistic differences, including the interdependence among language, operant feedback, thought, and experience, and the power of these to reconstruct and reassociate through reading constitute one barrier. Another is the effects of language on the total…

  20. Barriers vs Creativity in Translator Training

    Science.gov (United States)

    Yazici, Mine

    2016-01-01

    This paper discusses translation problems awaiting Turkish students as well as the creative solutions they develop in overcoming them. It consists of two parts; The first part studies the barriers concerning translation procedures from the perspective of translation theory and Turkish translation history; The second parts analyses the impact of…

  1. Characterization of a surface dielectric barrier discharge

    NARCIS (Netherlands)

    Pemen, A.J.M.; Beckers, F.J.C.M.; Heesch, van E.J.M.

    2009-01-01

    A surface dielectric barrier discharge (SDBD) reactor provides a homogeneous plasma over a large surface area. This allows surface treatments of foils, textiles or fibers. Here we present results of a study to characterize the AC and pulsed performance of SDBD with regard to ozone production,

  2. Dielectric barrier discharges applied for optical spectrometry

    Czech Academy of Sciences Publication Activity Database

    Brandt, S.; Schütz, A.; Klute, F. D.; Kratzer, Jan; Franzke, J.

    2016-01-01

    Roč. 123, SEP (2016), s. 6-32 ISSN 0584-8547 R&D Projects: GA ČR GA14-23532S Institutional support: RVO:68081715 Keywords : dielectric barrier discharge * analytical spectroscopy * applications Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.241, year: 2016

  3. Floating convection barrier for evaporation source

    International Nuclear Information System (INIS)

    1975-01-01

    A floating matrix of titanium in an uranium evaporation source, melted by an electron beam, serves as a barrier for preventing cooler material from reaching the evaporation area. This construction allows a big volume of melted uranium to be present and new uranium to be furnished in regulated intervals without manual intervention

  4. Deep inelastic scattering near the Coulomb barrier

    International Nuclear Information System (INIS)

    Gehring, J.; Back, B.; Chan, K.

    1995-01-01

    Deep inelastic scattering was recently observed in heavy ion reactions at incident energies near and below the Coulomb barrier. Traditional models of this process are based on frictional forces and are designed to predict the features of deep inelastic processes at energies above the barrier. They cannot be applied at energies below the barrier where the nuclear overlap is small and friction is negligible. The presence of deep inelastic scattering at these energies requires a different explanation. The first observation of deep inelastic scattering near the barrier was in the systems 124,112 Sn + 58,64 Ni by Wolfs et al. We previously extended these measurements to the system 136 Xe + 64 Ni and currently measured the system 124 Xe + 58 Ni. We obtained better statistics, better mass and energy resolution, and more complete angular coverage in the Xe + Ni measurements. The cross sections and angular distributions are similar in all of the Sn + Ni and Xe + Ni systems. The data are currently being analyzed and compared with new theoretical calculations. They will be part of the thesis of J. Gehring

  5. Innovation drivers and barriers in food processing

    NARCIS (Netherlands)

    Fortuin, F.T.J.M.; Omta, S.W.F.

    2009-01-01

    Purpose - The food processing industry, confronted with increased global competition and more stringent customer demands, is pressurized to improve the pace and quality of its innovation processes. This paper aims to find out what factors constitute the main drivers and barriers to innovation and to

  6. Air barrier details: How effective are they

    Energy Technology Data Exchange (ETDEWEB)

    A project was initiated to measure the air leakage through three typical details in wood frame walls: the header joist, electric outlets, and window openings. Three construction methods were tested: the poly approach, where a sealed internal polyethylene sheet and caulking provide the air barrier; an external air barrier approach using a continuous vapor permeable membrane sandwiched between two layers of external wall sheathing; and the airtight drywall approach (ADA), where the interior gypsum board finish along with framing and gaskets are the air barrier. Twelve sample panels using each of the three details were built using each of the construction approaches. A traditional wood-frame wall construction detail, with no effort made to create a continuous air barrier, was also built and tested for comparison. The samples were put in a test chamber so that air pressures could create infiltration or exfiltration through the panel under loads similar to those due to wind action. Measurements were made at several stages during construction of each sample to see the effect of different components on the air leakage. Overall, all but the traditional samples and the ADA electrical outlet panel exceeded the current tightness standards for glass and aluminum curtain walls. All three approaches could meet the airtightness standards of the R-2000 program. The total air leakage calculated for each approach is under 20% of that in traditional construction. Of the details tested, window detailing offers the greatest potential for increasing overall airtightness compared to traditional methods. 1 ref., 2 figs., 1 tab.

  7. Barriers to Distance Education in Rural Schools

    Science.gov (United States)

    Irvin, Matthew J.; Hannum, Wallace H.; Varre, Claire de la; Farmer, Thomas W.

    2010-01-01

    The primary purpose of the current study was to examine barriers to the use of distance education and explore related factors in small and low-income rural schools. Data were collected via a telephone survey with administrators or other qualified personnel. The sample involved 417 randomly selected small and low-income rural school districts…

  8. Udvikling af universitetsundervisning - rammer, barrierer og muligheder

    DEFF Research Database (Denmark)

    Horst, Sebastian; Jensen, Ane; Johannsen, Bjørn Friis

    2011-01-01

    Dansk Universitetspædagogisk Netværk (DUN) afholdt sin årlige konference i 2011 den 30.-31. maj med temaet “Udvikling af universitetsundervisning - rammer, barrierer og muligheder”. På konferencen arbejdede ca. 100 personer fra alle niveauer i universitetsverdenen på at beskrive hvordan vi kan...

  9. Motivations and Barriers in Promoting Preschool Education

    Science.gov (United States)

    Küçükturan, A. Güler; Akbaba Altun, Sadegül

    2017-01-01

    This study is designed to explore the reasons for sending and not sending preschool age children to preschools at an early age by exploring the motivations for and barriers towards promoting preschool education in Turkey. It aimed to determine various stakeholders' perceptions, attitudes, and knowledge related to preschool education in order to…

  10. Deep inelastic scattering near the Coulomb barrier

    Energy Technology Data Exchange (ETDEWEB)

    Gehring, J.; Back, B.; Chan, K. [and others

    1995-08-01

    Deep inelastic scattering was recently observed in heavy ion reactions at incident energies near and below the Coulomb barrier. Traditional models of this process are based on frictional forces and are designed to predict the features of deep inelastic processes at energies above the barrier. They cannot be applied at energies below the barrier where the nuclear overlap is small and friction is negligible. The presence of deep inelastic scattering at these energies requires a different explanation. The first observation of deep inelastic scattering near the barrier was in the systems {sup 124,112}Sn + {sup 58,64}Ni by Wolfs et al. We previously extended these measurements to the system {sup 136}Xe + {sup 64}Ni and currently measured the system {sup 124}Xe + {sup 58}Ni. We obtained better statistics, better mass and energy resolution, and more complete angular coverage in the Xe + Ni measurements. The cross sections and angular distributions are similar in all of the Sn + Ni and Xe + Ni systems. The data are currently being analyzed and compared with new theoretical calculations. They will be part of the thesis of J. Gehring.

  11. Uniting Control Lyapunov and Control Barrier Functions

    NARCIS (Netherlands)

    Romdlony, Zakiyullah; Jayawardhana, Bayu

    2014-01-01

    In this paper, we propose a nonlinear control design for solving the problem of stabilization with guaranteed safety. The design is based on the merging of a Control Lyapunov Function and a Control Barrier Function. The proposed control method allows us to combine the design of a stabilizer based on

  12. RF Current Drive in Internal Transport Barrier

    Energy Technology Data Exchange (ETDEWEB)

    Peysson, Y.; Basiuk, V.; Huysmans, G. [Association EURATOM-CEA, CEA/DSM/DRFC, CEA-Cadarache, 13 - St Paul-lez-Durance (France); Decker, J.; Bers, A.; Ram, A.K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA (United States)

    2005-07-01

    The current drive problem in regimes with internal transport barrier is addressed using a fast solver of the electron drift kinetic equation which may be used for arbitrary tokamak plasma magnetic equilibrium and any type of electron radio-frequency wave. Parametric studies are performed for the Lower Hybrid and Electron Cyclotron waves. (authors)

  13. Transport barriers in bootstrap-driven tokamaks

    Science.gov (United States)

    Staebler, G. M.; Garofalo, A. M.; Pan, C.; McClenaghan, J.; Van Zeeland, M. A.; Lao, L. L.

    2018-05-01

    Experiments have demonstrated improved energy confinement due to the spontaneous formation of an internal transport barrier in high bootstrap fraction discharges. Gyrokinetic analysis, and quasilinear predictive modeling, demonstrates that the observed transport barrier is caused by the suppression of turbulence primarily from the large Shafranov shift. It is shown that the Shafranov shift can produce a bifurcation to improved confinement in regions of positive magnetic shear or a continuous reduction in transport for weak or negative magnetic shear. Operation at high safety factor lowers the pressure gradient threshold for the Shafranov shift-driven barrier formation. Two self-organized states of the internal and edge transport barrier are observed. It is shown that these two states are controlled by the interaction of the bootstrap current with magnetic shear, and the kinetic ballooning mode instability boundary. Election scale energy transport is predicted to be dominant in the inner 60% of the profile. Evidence is presented that energetic particle-driven instabilities could be playing a role in the thermal energy transport in this region.

  14. Breaking the Barriers to the Circular Economy

    NARCIS (Netherlands)

    Kirchherr, J.W.; Hekkert, M.P.; Bour, Ruben; Huijbrechtse-Truijens, Anne; Kostense-Smit, Erica; Muller, Jennifer

    2017-01-01

    The Copernicus Institute of Sustainable Development, Utrecht University, the Netherlands and Deloitte have jointly carried out research on barriers to the Circular Economy (CE) in the European Union. For this research, a survey with 153 businesses, 55 government officials and expert interviews with

  15. Physical protection system using activated barriers

    International Nuclear Information System (INIS)

    Timm, R.E.; Zinneman, T.E.; Haumann, J.R.; Flaugher, H.A.; Reigle, D.L.

    1984-03-01

    The Argonne National Laboratory has recently installed an activated barrier, the Access Denial System, to upgrade its security. The technology of this system was developed in the late 70's by Sandia National Laboratory-Albuquerque. The Argonne National Laboratory is the first Department of Energy facility to use this device. Recent advancements in electronic components provide the total system support that makes the use of an activated barrier viable and desirable. The premise of an activated barrier is that it is deployed after a positive detection of an adversary is made and before the adversary can penetrate vital area. To accomplish this detection, sophisticated alarms, assessment, and communications must be integrated into a system that permits a security inspector to make a positive evaluation and to activate the barrier. The alarm sensor locations are selected to provide protection in depth. Closed circuit television is used with components that permit multiple video frames to be stored for automated, priority-based playback to the security inspector. Further, algorithms permit look-ahead surveillance of vital areas so that the security inspector can activate the access denial system in a timely manner and not be restricted to following the adversaries' penetration path(s)

  16. Understanding Motivators and Barriers to Physical Activity

    Science.gov (United States)

    Patay, Mary E.; Patton, Kevin; Parker, Melissa; Fahey, Kathleen; Sinclair, Christina

    2015-01-01

    The purpose of this study was to understand the factors that influence physical activity among year-round residents in an isolated summer resort community. Specifically, we explored the personal, environmental, social, and culture-specific perceived motivators and barriers to physical activity. Participants were formally interviewed about their…

  17. Engineered Barrier System: Physical and Chemical Environment

    International Nuclear Information System (INIS)

    Dixon, P.

    2004-01-01

    The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports

  18. Transcending communication barriers: A case for hybrid ...

    African Journals Online (AJOL)

    Therefore, communication can be improved by combining both feminine and masculine styles of communication, because male and female leaders can adapt to the demands of leadership in the transformational mode. Key words: secondary school; transformational leadership; channels of communication; cultural barriers ...

  19. Natural and Synthetic Barriers to Immobilize Radionuclides

    International Nuclear Information System (INIS)

    Um, W.

    2011-01-01

    The experiments of weathering of glass waste form and the reacted sediments with simulated glass leachates show that radionuclide sequestration can be significantly enhanced by promoting the formation of secondary precipitates. In addition, synthetic phosphate-bearing nanoporous material exhibits high stability at temperature and has a very high K d value for U(VI) removal. Both natural and synthetic barrier materials can be used as additional efficient adsorbents for retarding transport of radionuclides for various contaminated waste streams and waste forms present at U. S. Department of Energy clean-up sites and the proposed geologic radioactive waste disposal facility. In the radioactive waste repository facility, natural or synthetic materials are planned to be used as a barrier material to immobilize and retard radionuclide release. The getter material can be used to selectively scavenge the radionuclide of interest from a liquid waste stream and subsequently incorporate the loaded getters in a cementitious or various monolithic waste forms. Also, the getter material is to reduce the release of radionuclides from monolithic waste forms. Also, the getter material is to reduce the release of radionuclides from monolithic waste forms. Also, the getter material is to reduce the release of radionuclides form monolithic waste forms by being emplaced as a backfill barrier material around the wastes or waste form to minimize the potential around the wastes or waste form to minimize the potential hazard of leached radioactive wastes. The barrier material should be highly efficient to sequester radionuclides and possess physical and chemical stability for long-term exposure to severe weathering conditions. Because potential leaching of radionuclides depends on various environmental and weathering conditions of the near-field repository, the barrier materials must be durable and not disintegrate under a range of moisture, temperature, pressure, radiation, Eh, ph. and

  20. MENDING THE IN SITU MANIPULATION BARRIER

    Energy Technology Data Exchange (ETDEWEB)

    PETERSEN, S.W.

    2006-02-06

    In early 2004, the U.S. Department of Energy (DOE) Richland and Fluor Hanford requested technical assistance from the DOE Headquarters EM-23 Technical Assistance Program to provide a team of technical experts to develop recommendations for mending the In Situ Redox Manipulation (ISRM) Barrier in the 100-D Area of the Hanford Site in Washington State. To accommodate this request, EM-23 provided support to convene a group of technical experts from industry, a national laboratory, and a DOE site to participate in a 2 1/2-day workshop with the objective of identifying and recommending options to enhance the performance of the 100-D Area reactive barrier and of a planned extension to the northeast. This report provides written documentation of the team's findings and recommendations. In 1995, a plume of dissolved hexavalent chromium [Cr(VI)], which resulted from operation of the D/DR Reactors at the Hanford site, was discovered along the Columbia River shoreline and in the 100-D Area. Between 1999 and 2003, a reactive barrier using the In Situ Redox Manipulation (ISRM) technology, was installed a distance of 680 meters along the river to reduce the Cr(VI) in the groundwater. The ISRM technology creates a treatment zone within the aquifer by injection of sodium dithionite, a strong reducing agent that scavenges dissolved oxygen (DO) from the aquifer and reduces ferric iron [Fe(III)], related metals, and oxy-ions. The reduction of Fe(III) to ferrous [Fe(II)] iron provides the primary reduction capacity to reduce Cr(VI) to the +3 state, which is less mobile and less toxic. Bench-scale and field-scale treatability tests were initially conducted to demonstrate proof-of principle and to provide data for estimation of barrier longevity. These calculations estimated barrier longevity in excess of twenty years. However, several years after initial and secondary treatment, groundwater in a number of wells has been found to contain elevated chromium (Cr) concentrations

  1. Identifying and overcoming barriers to technology implementation

    International Nuclear Information System (INIS)

    Bailey, M.; Warren, S.; McCune, M.

    1996-01-01

    In a recent General Accounting Office report, the Department of Energy's (DOE) Office of Environmental Management was found to be ineffective in integrating their environmental technology development efforts with the cleanup actions. As a result of these findings, a study of remediation documents was performed by the Technology Applications Team within DOE's Office of Environmental Restoration (EM-40) to validate this finding and to understand why it was occurring. A second initiative built on the foundation of the remediation document study and evaluated solutions to the ineffective implementation of improved technologies. The Technology Applications Team examined over 50 remediation documents (17 projects) which included nearly 600 proposed remediation technologies. It was determined that very few technologies are reaching the Records of Decision documents. In fact, most are eliminated in the early stages of consideration. These observations stem from regulators' and stakeholders' uncertainties in cost and performance of the technology and the inability of the technology to meet site specific conditions. The Technology Applications Team also set out to identify and evaluate solutions to barriers to implementing innovative technology into the DOE's environmental management activities. Through the combined efforts of DOE and the Hazardous Waste Action Coalition (HWAC), a full day workshop was conducted at the annual HWAC meeting in June 1995 to solve barriers to innovative technology implementation. Three barriers were identified as widespread throughout the DOE complex and industry. Identified barriers included a lack of verified or certified cost and performance data for innovative technologies; risk of failure to reach cleanup goals using innovative technologies; and communication barriers that are present at virtually every stage of the characterization/remediation process from development through implementation

  2. Electrolyte diffusion in compacted montmorillonite engineered barriers

    International Nuclear Information System (INIS)

    Jahnke, F.M.; Radke, C.J.

    1985-09-01

    The bentonite-based engineered barrier or packing is a proposed component of several designs conceived to dispose of high-level nuclear waste in geologic repositories. Once radionuclides escape the waste package, they must first diffuse through the highly impermeable clay-rich barrier before they reach the host repository. To determine the effectiveness of the packing as a sorption barrier in the transient release period and as a mass-transfer barrier in the steady release period over the geologic time scales involved in nuclear waste disposal, a fundamental understanding of the diffusion of electrolytes in compacted clays is required. We present, and compare with laboratory data, a model quantifying the diffusion rates of cationic cesium and uncharged tritium in compacted montmorillonite clay. Neutral tritium characterizes the geometry (i.e., tortuosity) of the particulate gel. After accounting for cation exchange, we find that surface diffusion is the dominant mechanism of cation transport, with an approximate surface diffusion coefficient of 2 x 10 -6 cm 2 /s for cesium. This value increases slightly with increasing background ionic strength. The implications of this work for the packing as a migration barrier are twofold. During the transient release period, K/sub d/ values are of little importance in retarding ion migration. This is because sorption also gives rise to a surface diffusion path, and it is surface diffusion which controls the diffusion rate of highly sorbing cations in compacted montmorillonite. During the steady release period, the presence of surface diffusion leads to a flux through the packing which is greatly enhanced. In either case, if surface diffusion is neglected, the appropriate diffusion coefficient of ions in compacted packing will be in considerable error relative to current design recommendations. 11 refs., 4 figs., 1 tab

  3. Transport Barriers in Bootstrap Driven Tokamaks

    Science.gov (United States)

    Staebler, Gary

    2017-10-01

    Maximizing the bootstrap current in a tokamak, so that it drives a high fraction of the total current, reduces the external power required to drive current by other means. Improved energy confinement, relative to empirical scaling laws, enables a reactor to more fully take advantage of the bootstrap driven tokamak. Experiments have demonstrated improved energy confinement due to the spontaneous formation of an internal transport barrier in high bootstrap fraction discharges. Gyrokinetic analysis, and quasilinear predictive modeling, demonstrates that the observed transport barrier is due to the suppression of turbulence primarily due to the large Shafranov shift. ExB velocity shear does not play a significant role in the transport barrier due to the high safety factor. It will be shown, that the Shafranov shift can produce a bifurcation to improved confinement in regions of positive magnetic shear or a continuous reduction in transport for weak or negative magnetic shear. Operation at high safety factor lowers the pressure gradient threshold for the Shafranov shift driven barrier formation. The ion energy transport is reduced to neoclassical and electron energy and particle transport is reduced, but still turbulent, within the barrier. Deeper into the plasma, very large levels of electron transport are observed. The observed electron temperature profile is shown to be close to the threshold for the electron temperature gradient (ETG) mode. A large ETG driven energy transport is qualitatively consistent with recent multi-scale gyrokinetic simulations showing that reducing the ion scale turbulence can lead to large increase in the electron scale transport. A new saturation model for the quasilinear TGLF transport code, that fits these multi-scale gyrokinetic simulations, can match the data if the impact of zonal flow mixing on the ETG modes is reduced at high safety factor. This work was supported by the U.S. Department of Energy under DE-FG02-95ER54309 and DE-FC02

  4. Hanford protective barriers program: Status of asphalt barrier studies - FY 1989

    International Nuclear Information System (INIS)

    Freeman, H.D.; Gee, G.W.

    1989-11-01

    The Hanford Protective Barrier Program is evaluating alternate barriers to provide a means of meeting stringent water infiltration requirements. One type of alternate barrier being considered is an asphalt-based layer, 1.3 to 15 cm thick. Evaluations of these barriers were initiated in FY 1988, and, based on laboratory studies, two asphalt formulations were selected for further testing in small-tube lysimeters: a hot rubberized asphalt and an admixture of cationic asphalt emulsion and concrete sand containing 24 wt% residual asphalt. Eight lysimeters containing asphalt seals were installed as part of the Small Tube Lysimeter Test Facility on the Hanford Site. Two control lysimeters containing Hanford sand with a surface gravel treatment were also installed for comparison. 5 refs., 13 figs., 1 tab

  5. Differential Rollover Risk in Vehicle-to-Traffic Barrier Collisions

    Science.gov (United States)

    Gabauer, Douglas J.; Gabler, Hampton C.

    2009-01-01

    In the roadside safety community, there has been debate over the influence of vehicle and barrier type on rollover rates in traffic barrier crashes. This study investigated rollover rates between sport utility vehicles (SUVs), pickup trucks, and cars in vehicle-traffic barrier crashes and has examined the effect of barrier type on rollover risk for concrete barrier and metal barrier impacts. The analysis included 955 barrier impact cases that were selected from 11-years of in-depth crash data available through the National Automotive Sampling System (NASS) / Crashworthiness Data System (CDS). In real world tow-away level longitudinal barrier collisions, the most important predictors of vehicle rollover were found to be vehicle type and whether the vehicle was tracking prior to barrier impact. Based on binary logistic regression, SUVs were found to have 8 times the risk of rollover as cars in barrier impacts. Although pickups were found to have an increased risk of rollover compared to cars, the risk was not as pronounced as that found for SUVs. This finding has direct implications for the full scale crash testing of longitudinal barriers as the testing procedures have been predicated on the assumption that the pickup truck provides a critical or worst case impact scenario. In towaway crashes, our study does not support the notion that concrete barriers have a higher risk of vehicle rollover than metal beam barriers. PMID:20184839

  6. Improved Barriers to Turbine Engine Fragments: Final Annual Report

    National Research Council Canada - National Science Library

    Shockey, Donald

    2002-01-01

    .... Previous large-scale fragment impact testing of comer peg-mounted fabric barriers indicated that the failure of the fabric around the pegged hole was a significant factor in the barrier's effectiveness...

  7. Performance of Traffic Noise Barriers with Varying Cross-Section

    Directory of Open Access Journals (Sweden)

    Sanja Grubeša

    2011-05-01

    Full Text Available The efficiency of noise barriers largely depends on their geometry. In this paper, the performance of noise barriers was simulated using the numerical Boundary Element Method (BEM. Traffic noise was particularly considered with its standardized noise spectrum adapted to human hearing. The cross-section of the barriers was varied with the goal of finding the optimum shape in comparison to classical rectangular barriers. The barrier performance was calculated at different receiver points for a fixed barrier height and source position. The magnitude of the insertion loss parameter was used to evaluate the performance change, both in one-third octave bands and as the broadband mean insertion loss value. The proposed barriers of varying cross-section were also compared with a typical T-shape barrier of the same height.

  8. Engineered barrier development for a nuclear waste repository in basalt

    International Nuclear Information System (INIS)

    Smith, M.J.

    1980-05-01

    The BWIP Engineered Barrier Program has been developed to provide an integrated approach to the development of site-specific Engineered Barrier assemblages for a repository located in basalt. The goal of this program is to specify engineered and natural barriers which will ensure that nuclear and non-radioactive hazardous materials emplaced in a repository in basalt do not exceed acceptable rates of release to the biosphere. A wide range of analytical and experimental activities related to the basalt repository environment, waste package environment, waste/barrier/rock interactions, and barrier performance assessment provide the basis for selection of systems capable of meeting licensing requirements. Work has concentrated on specifying and testing natural and man-made materials which can be used to plug boreholes in basalt and which can be used as multiple barriers to surround nuclear waste forms and containers. The Engineered Barriers Program is divided into two major activities: multiple barrier studies and borehole plugging. 8 figures, 4 tables

  9. Evaluation of Subsurface Engineered Barriers at Waste Sites

    National Research Council Canada - National Science Library

    1998-01-01

    .... Environmental Protection Agency's (EPA) waste programs with a national retrospective analysis of barrier field performance, and information that may be useful in developing guidance on the use and evaluation of barrier systems...

  10. Barriers to utilization of modern methods of family planning amongst ...

    African Journals Online (AJOL)

    Barriers to utilization of modern methods of family planning amongst women in a ... is recognized by the world health organization (WHO) as a universal human right. ... Conclusion: The study finds numerous barriers to utilization of family ...

  11. Energy analysis of vehicle-to-cable barrier impacts.

    Science.gov (United States)

    2013-06-01

    An accident reconstruction technique was developed for estimating the energy absorbed during an impact with a cable barrier system as well as the initial impact velocity. The kinetic energy absorbed during a cable barrier system impact is comprised o...

  12. Transparent Barrier Urethanes Based on Polyethylene Soft Segments

    National Research Council Canada - National Science Library

    Beck

    2000-01-01

    ...%. Flexible, transparent materials were produced. The mechanical and barrier properties of these urethanes were evaluated for comparison with the performance of traditional flexible barrier materials (e.g., butyl rubber...

  13. Transport of the moving barrier driven by chiral active particles

    Science.gov (United States)

    Liao, Jing-jing; Huang, Xiao-qun; Ai, Bao-quan

    2018-03-01

    Transport of a moving V-shaped barrier exposed to a bath of chiral active particles is investigated in a two-dimensional channel. Due to the chirality of active particles and the transversal asymmetry of the barrier position, active particles can power and steer the directed transport of the barrier in the longitudinal direction. The transport of the barrier is determined by the chirality of active particles. The moving barrier and active particles move in the opposite directions. The average velocity of the barrier is much larger than that of active particles. There exist optimal parameters (the chirality, the self-propulsion speed, the packing fraction, and the channel width) at which the average velocity of the barrier takes its maximal value. In particular, tailoring the geometry of the barrier and the active concentration provides novel strategies to control the transport properties of micro-objects or cargoes in an active medium.

  14. Therapeutic benefits of enhancing permeability barrier for atopic eczema

    Directory of Open Access Journals (Sweden)

    George Man

    2015-06-01

    Full Text Available The regulatory role of epidermal permeability barrier function in cutaneous inflammation has been well appreciated. While barrier disruption induces cutaneous inflammation, improvement of permeability barrier function alleviates inflammation. Studies have demonstrated that improvement of epidermal permeability barrier function not only prevents the development of atopic eczema, but also delays the relapse of these diseases. Moreover, enhancing the epidermal permeability barrier also alleviates atopic eczema. Furthermore, co-applications of barrier enhancing products with glucocorticoids can increase the therapeutic efficacy and reduce the adverse effects of glucocorticoids in the treatment of atopic eczema. Therefore, utilization of permeability barrier enhancing products alone or in combination with glucocorticoids could be a valuable approach in the treatment of atopic eczema. In this review, we discuss the benefits of improving the epidermal permeability barrier in the management of atopic eczema.

  15. Electronically Induced Redox Barriers for Treatment of Groundwater

    National Research Council Canada - National Science Library

    Sale, Tom; Gilbert, David

    2006-01-01

    ...) and Colorado State University (CSU). The focus is an innovative electrolytic approach for managing redox-sensitive contaminants in groundwater, referred to as electrically induced redox barrier (e-barriers...

  16. Crossing safety barriers: influence of children's morphological and functional variables.

    Science.gov (United States)

    Cordovil, Rita; Vieira, Filomena; Barreiros, João

    2012-05-01

    Thirty-three children between 3 and 6 years of age were asked to climb four different types of safety barriers. Morphological and functional variables of the children, which were expected to influence climbing or passing through skills, were collected. The influence of those variables on children's success rate and time to cross was tested. No barrier offered a total restraining efficacy. The horizontal bars barrier was crossed by 97% of the children. In the group of children that succeeded in crossing the four barriers, mean time to cross the most difficult barrier was 15 s. Age was the best predictor for success in crossing most barriers but morphology and strength were important predictors of time to cross. The influence of anthropometric variables in time to cross was dependent upon the characteristics of the barrier. A good design of safety barriers should consider children's age, morphology and strength. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  17. Overcoming Barriers to Wind Development in Appalachian Coal Country

    Energy Technology Data Exchange (ETDEWEB)

    Brent Bailey; Evan Hansen

    2012-10-09

    This research project synthesizes existing data and communication from experts to assess barriers to wind development in Pennsylvania, Maryland, West Virginia, Virginia, and Kentucky, and makes recommendations where feasible to reduce or eliminate those barriers.

  18. Prototype Engineered Barrier System Field Tests

    International Nuclear Information System (INIS)

    Ramirez, A.L.; Beatty, J.; Buscheck, T.A.

    1989-01-01

    This paper presents selected preliminary results obtained during the first 54 days of the Prototype Engineered Barrier System Field Tests (PEBSFT) that are being performed in G-Tunnel within the Nevada Test Site. The test described is a precursor to the Engineered Barrier Systems Field Tests (EBSFT). The EBSFT will consist of in situ tests of the geohydrologic and geochemical environment in the near field (within a few meters) of heaters emplaced in welded tuff to simulate the thermal effects of waste packages. The PEBSFTs are being conducted to evaluate the applicability of measurement techniques, numerical models, and procedures for future investigations that will be conducted in the Exploratory Shaft Facilities of the Yucca Mountain Project (YMP). The paper discusses the evolution of hydrothermal behavior during the prototype test, including rock temperatures, changes in rock moisture content, air permeability of fractures, gas pressures, and rock mass gas-phase humidity. 10 refs., 12 figs

  19. NATURAL BARRIERS TARGETED THRUST FY 2004 PROJECTS

    International Nuclear Information System (INIS)

    NA

    2005-01-01

    This booklet contains project descriptions of work performed by the Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), Office of Science and Technology and International's (OSTandI) Natural Barriers Targeted Thrust during Fiscal Year (FY) 2004. The Natural Barriers Targeted Thrust is part of OSTandI's Science and Technology Program which supports the OCRWM mission to manage and dispose of high-level radioactive waste and spent nuclear fuel in a manner that protects health, safety, and the environment; enhances national and energy security; and merits public confidence. In general, the projects described will continue beyond FY 2004 assuming that the technical work remains relevant to the proposed Yucca Mountain Repository and sufficient funding is made available to the Science and Technology Program

  20. Exercising at work: barriers to women's participation.

    Science.gov (United States)

    Verhoef, M J; Hamm, R D; Love, E J

    1993-06-01

    Only a minority of women in an urban random sample have the opportunity to exercise at work, and even fewer women use these opportunities. Lack of time and inconvenient times are the major reasons for not participating in exercise programs at work. Exercise programs at work are used by women who are already physically active, suggesting that workplace exercise programs do not serve the needs of women who may need exercise programs most. Multivariate analysis shows that age, having children, lack of energy, and lack of support are significant barriers to women's exercise participation at work. The results of this study suggest a leadership opportunity for on site occupational health nurses in addressing these barriers to workplace exercise.

  1. The biological significance of brain barrier mechanisms

    DEFF Research Database (Denmark)

    Saunders, Norman R; Habgood, Mark D; Møllgård, Kjeld

    2016-01-01

    , but more work is required to evaluate the method before it can be tried in patients. Overall, our view is that much more fundamental knowledge of barrier mechanisms and development of new experimental methods will be required before drug targeting to the brain is likely to be a successful endeavor......Barrier mechanisms in the brain are important for its normal functioning and development. Stability of the brain's internal environment, particularly with respect to its ionic composition, is a prerequisite for the fundamental basis of its function, namely transmission of nerve impulses....... In addition, the appropriate and controlled supply of a wide range of nutrients such as glucose, amino acids, monocarboxylates, and vitamins is also essential for normal development and function. These are all cellular functions across the interfaces that separate the brain from the rest of the internal...

  2. Investigating the barriers on media privatization

    Directory of Open Access Journals (Sweden)

    Roghiyeh Jame

    2013-01-01

    Full Text Available During the past few years, there has been growing interests in reducing cost of products and services among developing countries. Privatization is believed to be one of the most important techniques to increase relative efficiencies of publically held organizations. In this paper, we study important barriers on privatization of television (TV media industry in Iran. The proposed study of this paper designs and distributes a questionnaire using a sample of 234 out of 600 graduate students who were enrolled in media communication studies and examined six hypotheses based on one-side t-student. The survey considers different factors influencing privatization of TV media industry. The results of the investigation indicate that the cost of TV production, short and long-term investment security, people's interest on investing on TV media industry, building appropriate culture, cultural obstacles and economic barriers influence media privatization, significantly.

  3. NATURAL BARRIERS TARGETED THRUST FY 2004 PROJECTS

    Energy Technology Data Exchange (ETDEWEB)

    NA

    2005-07-27

    This booklet contains project descriptions of work performed by the Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), Office of Science and Technology and International's (OST&I) Natural Barriers Targeted Thrust during Fiscal Year (FY) 2004. The Natural Barriers Targeted Thrust is part of OST&I's Science and Technology Program which supports the OCRWM mission to manage and dispose of high-level radioactive waste and spent nuclear fuel in a manner that protects health, safety, and the environment; enhances national and energy security; and merits public confidence. In general, the projects described will continue beyond FY 2004 assuming that the technical work remains relevant to the proposed Yucca Mountain Repository and sufficient funding is made available to the Science and Technology Program.

  4. Direct access tariffs and barriers to choice

    International Nuclear Information System (INIS)

    Levson, D.

    1999-01-01

    The current situation of the power market in Alberta was reviewed. Based on this review is was concluded that the province is a long way from being a competitive, liquid power market. Further, it was predicted that unless large power purchasers get actively involved in managing their options, identify realistic and competitive supply options and actively campaign for the removal of barriers to choice, they will experience significant cost increases in the year 2001 and beyond, due in large measure to the market power exercised by the four major utilities (TAU, EPCOR, APL and Powerex). Barriers to new supply such as the high cost of standby, uncertainties about transmission and natural gas prices, the delays to cogeneration caused by low oil prices, and the design of direct access tariffs by utilities, were also explored. The cumulative contribution of these factors to uncertainties in pool price, fixed price and transmission and distribution costs were outlined

  5. Greatest barrier is retaining young scientists

    Science.gov (United States)

    Chandler, Mark; Hopper, John

    The National Science Foundation's top priorities as listed by director Neal Lane in Eos (November 9) are to strengthen NSF and its support of scientific research and education, to better articulate to the public why it is so important that support of science and engineering be strengthened, and to continue to lower barriers that discourage young people from choosing careers in science.While we firmly support the first two priorities, we are concerned about the underlying assumptions and implications of the third. Barriers discouraging women and minorities from considering careers in math and science do exist within our educational system, and there is now abundant statistical evidence showing these groups are under-represented in most fields of science. However, as stated in the Eos article, solving these problems and leveling the playing field is not the primary goal of the NSF policy.

  6. Infiltration barrier demonstration at Maxey Flats, Kentucky

    International Nuclear Information System (INIS)

    Mills, D.; Razor, J.

    1983-01-01

    At the 1982 DOE LLWMP meeting, the Kentucky Natural Resources and Environmental Protection Cabinet presented a history of the Maxey Flats Waste Disposal Facility, its status, and current Commonwealth activities leading toward stabilization and decommissioning. Information was presented at that time on the purpose of the DOE Trench Moisture Barrier Demonstration Grant and the early phases of construction and implementation. In this paper, final construction and implementation of the trench moisture barrier demonstration are discussed. Data including trench water level measurements, lateral liquid flow in experimental sections, and soil moisture measurements are presented and discussed. The Paper is completed with a brief discussion of remediation activities currently being implemented at Maxey Flats. 9 references, 7 figures, 1 table

  7. Investing in Energy Efficiency. Removing the Barriers

    International Nuclear Information System (INIS)

    2004-01-01

    Investing in improving energy efficiency has the clear advantages of reducing energy costs, improving security of supply and mitigating the environmental impacts of energy use. And still, many viable opportunities for higher energy efficiency are not tapped because of the existence of numerous barriers to such investments. These lost opportunities imply costs to the individual energy consumers and to the society as a whole and they are particularly important in economies in transition. This report identifies various types of barriers for making energy efficiency investments (be they of legal, administrative, institutional or financial nature), mainly in buildings, district heating and efficient lighting. The role of various bodies and organisations for the facilitation of energy efficiency investments is analysed, from public authorities and regulators to banks and international financing institutions

  8. Osteoarthritis guidelines: Barriers to implementation and solutions.

    Science.gov (United States)

    Ferreira de Meneses, Sarah; Rannou, Francois; Hunter, David J

    2016-06-01

    Osteoarthritis (OA) is a leading cause of disability worldwide. Clinical practice guidelines (CPGs) have been developed to facilitate improved OA management. Scientific communities worldwide have proposed CPGs for OA treatment. Despite the number of highly prominent guidelines available and their remarkable consistency, their uptake has been suboptimal. Possibly because of the multitude of barriers related to the implementation of CPGs. For example, different guidelines show contradictions, some lack evidence, and they lack a hierarchy or tools to facilitate their translation and application. Also, the guidelines do not acknowledge the effect of comorbidities on choosing the treatments. Finally, poor integration of multidisciplinary services within and across healthcare settings is a major barrier to the effective implementation of management guidelines. Here we describe the main problems related to the OA guidelines and some solutions so as to offer some guidance on the elaboration of future CPGs and their implementation in primary care. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Decreasing barriers for nurse practitioner social entrepreneurship.

    Science.gov (United States)

    Sharp, Dayle B; Monsivais, Diane

    2014-10-01

    To describe difficulties associated with the business-related aspects of practice in role transition of rural nurse practitioners (NPs), and to give practice implications. This focused ethnographic study derived data from semi-structured interviews. Participants provided information about rural NP practice ownership and barriers. The sample consisted of 24 rural NPs living throughout the United States. The majority were 51-60 years of age (45%) and females (93%) who had been in rural practice for 1 to over 20 years. NP social entrepreneurs experience difficulties related to scope of practice, business skills, and role conflict. To decrease barriers for NP clinic ownership and management, NPs need to receive education related to financing a rural practice, legal/regulatory practices, strategic planning, leadership, and clinic management. ©2014 American Association of Nurse Practitioners.

  10. Sub-barrier photofission of 238U

    International Nuclear Information System (INIS)

    Bhandari, B.S.

    Photofission cross section of 238 U below threshold have been calculated using a double humped potential barrier parameterized by smoothly joining four parabolas, and a coulomb potential at and beyond the scission point. Relative strength in the fission channel has been calculated and an attempt has been made to interpret the apparent resonance structures observed recently in photofission experiments of 238 U as excited states of the fission isomer. A set of parameters for a double humped barrier are found which are consistent with known spontaneous fission and isomeric fission half lives. In addition to reproducing satisfactorily the observed resonance structure near threshold, the calculation also predicts several low energy resonances in the cross sections [pt

  11. Fire barrier problems-part 3

    International Nuclear Information System (INIS)

    Verna, B.J.

    1993-01-01

    This article deals with problems associated with a thermal barrier material called Thermo-Lag 330. Typically in nuclear applications this material is used to provide either 1 hour (1/2 inch thick) or 3 hour (1 inch thick) barriers to prevent the spread of fires between redundant safety systems, and to protect cable trays and conduit. The article reviews concerns within the nuclear industry as to the proper handling of the material, how to interpret the data available on the material, the apparant conflicting assessments of the material when tested by different groups, etc. Research is ongoing on the suitability of the material, but the article points out that the manufacturer feels it should be installed by properly trained installers, the joints sealed with a grouting material, properly bundled to maintain its integrity, have a complete stress skin, and not be walked on after installation in order to function properly

  12. Nuclear reactor vessel fuel thermal insulating barrier

    Science.gov (United States)

    Keegan, C. Patrick; Scobel, James H.; Wright, Richard F.

    2013-03-19

    The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel that has a hemispherical lower section that increases in volume from the center line of the reactor to the outer extent of the diameter of the thermal insulating barrier and smoothly transitions up the side walls of the vessel. The space between the thermal insulating harrier and the reactor vessel forms a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive inlet valve for the cooling water includes a buoyant door that is normally maintained sealed under its own weight and floats open when the cavity is Hooded. Passively opening steam vents are also provided.

  13. BARRIERS TO PHYSICAL ACTIVITY IN THE ELDERLY

    Directory of Open Access Journals (Sweden)

    Paulo Matias

    2015-04-01

    Full Text Available The population awareness of the physical exercise’s benefits is widely diffused. These benefits are particularly important in the elderly because, with increasing age, there is a decline of the musculoskeletal system and the maximum oxygen consumption which reduces the functional fitness of the elderly and can often lead to a significant decline in the quality of life. Despite this awareness, a large part of the population remains sedentary. It is important to know what the barriers are, so they can be circumvented in order to increase the engagement of the elderly population in existing physical activity programs.Objectives: This study aims to identify some of the personal, behavioral and environmental barriers that prevent older adults to be physically active.

  14. Renewable energy costs, potentials, barriers: Conceptual issues

    International Nuclear Information System (INIS)

    Verbruggen, Aviel; Fischedick, Manfred; Moomaw, William; Weir, Tony; Nadai, Alain; Nilsson, Lars J.; Nyboer, John; Sathaye, Jayant

    2010-01-01

    Renewable energy can become the major energy supply option in low-carbon energy economies. Disruptive transformations in all energy systems are necessary for tapping widely available renewable energy resources. Organizing the energy transition from non-sustainable to renewable energy is often described as the major challenge of the first half of the 21st century. Technological innovation, the economy (costs and prices) and policies have to be aligned to achieve full renewable energy potentials, and barriers impeding that growth need to be removed. These issues are also covered by IPCC's special report on renewable energy and climate change to be completed in 2010. This article focuses on the interrelations among the drivers. It clarifies definitions of costs and prices, and of barriers. After reviewing how the third and fourth assessment reports of IPCC cover mitigation potentials and commenting on definitions of renewable energy potentials in the literature, we propose a consistent set of potentials of renewable energy supplies.

  15. Social Barriers to Effective Communication in Old Age

    OpenAIRE

    Anna Sanecka

    2014-01-01

    Some communication barriers apply particularly to elderly people. The social barriers to effective communication in old age are the barriers caused by stereotypes of old age/elderly people and the barriers arising from limitations in using mass communication by seniors. Stereotypes of old age/elderly people embrace views regarding old people’s communication skills and the ideas about the correct way of communication with them. Therefore the communication problems of old people are correlated ...

  16. Theoretical analysis of the rotational barrier of ethane.

    Science.gov (United States)

    Mo, Yirong; Gao, Jiali

    2007-02-01

    The understanding of the ethane rotation barrier is fundamental for structural theory and the conformational analysis of organic molecules and requires a consistent theoretical model to differentiate the steric and hyperconjugation effects. Due to recently renewed controversies over the barrier's origin, we developed a computational approach to probe the rotation barriers of ethane and its congeners in terms of steric repulsion, hyperconjugative interaction, and electronic and geometric relaxations. Our study reinstated that the conventional steric repulsion overwhelmingly dominates the barriers.

  17. Piezotronically modified double Schottky barriers in ZnO varistors.

    Science.gov (United States)

    Raidl, Nadine; Supancic, Peter; Danzer, Robert; Hofstätter, Michael

    2015-03-25

    Double Schottky barriers in ZnO are modified piezotronically by the application of mechanical stresses. New effects such as the enhancement of the potential barrier height and the increase or decrease of the natural barrier asymmetry are presented. Also, an extended model for the piezotronic modification of double Schottky barriers is given. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. How to break the barriers to climate awareness

    DEFF Research Database (Denmark)

    Kemp, Peter

    2016-01-01

    In this paper is provided a philosophical analysis of the cognitive barriers that may block the individual citizen’s acknowledgement of a personal responsibility to engage in climate responsible behaviour. The authors distinguish between two types of cognitive barriers; the physical barriers......, that are associated with the way we gain knowledge about climate change and the physical world state; and the psychological barriers, that arise from ideas about ourselves and the nature that surrounds us....

  19. Ethics case reflection sessions: Enablers and barriers.

    Science.gov (United States)

    Bartholdson, Cecilia; Molewijk, Bert; Lützén, Kim; Blomgren, Klas; Pergert, Pernilla

    2018-03-01

    In previous research on ethics case reflection (ECR) sessions about specific cases, healthcare professionals in childhood cancer care were clarifying their perspectives on the ethical issue to resolve their main concern of consolidating care. When perspectives were clarified, consequences in the team included 'increased understanding', 'group strengthening' and 'decision grounding'. Additional analysis of the data was needed on conditions that could contribute to the quality of ECR sessions. The aim of this study was to explore conditions for clarifying perspectives during ECR sessions. Data were collected from observations and interviews and the results emerged from an inductive analysis using grounded theory. Participants and research context: Six observations during ECR sessions and 10 interviews were performed with healthcare professionals working in childhood cancer care and advanced paediatric homecare. Ethical considerations: The study was approved by a regional ethical review board. Participants were informed about their voluntary involvement and that they could withdraw their participation without explaining why. Two categories emerged: organizational enablers and barriers and team-related enablers and barriers. Organizational enablers and barriers included the following sub-categories: the timing of the ECR session, the structure during the ECR session and the climate during the ECR session. Sub-categories to team-related enablers and barriers were identified as space for inter-professional perspectives, varying levels of ethical skills and space for the patient's and the family's perspectives. Space for inter-professional perspectives included the dominance of a particular perspective that can result from hierarchical positions. The medical perspective is relevant for understanding the child's situation but should not dominate the ethical reflection. Conditions for ECR sessions have been explored and the new knowledge can be used when training

  20. Radiant Barriers Save Energy in Buildings

    Science.gov (United States)

    2014-01-01

    Langley Research Center needed to coat the Echo 1 satellite with a fine mist of vaporized metal, and collaborated with industry to create "radiant barrier technology." In 2010, Ryan Garrett learned about a new version of the technology resistant to oxidation and founded RadiaSource in Ogden, Utah, to provide the NASA-derived technology for applications in homes, warehouses, gymnasiums, and agricultural settings.

  1. Chaos near the Coulomb barrier. Nuclear molecules

    International Nuclear Information System (INIS)

    Strayer, M.R.

    1984-01-01

    The present work examines in detail the classical behavior of the α + 14 C and the 12 C + 12 C(O + ) collison at energies near the Coulomb barrier. The long-time motion of the compound nuclear system is identified in terms of its classical quasiperiodic and chaotic behavior. The consequences of this motion are discussed and interpreted in terms of the evolution of the system along a dynamical energy surface. 45 references

  2. Light Barrier for Non-Foil Packaging

    Science.gov (United States)

    2010-12-16

    foil and all-plastic materials were retorted and a second set of all-plastic packaged entrees were Microwave Sterilized on the Washington State...Copolymers for Retort Applications; SPE Polyolefins and Flexible Packaging Conference: Society of Plastics Engineers. Newtown. CT, 43pp. Thellen C...Final Scientific Report Light Barrier for Non-Foil Packaging Contract No. W911QY-08-C-0132 Final Scientific Report Contract No. W911QY-08-C-0132

  3. Regulatory Barriers Blocking Standardization of Interoperability

    OpenAIRE

    Zhong, Daidi; Kirwan, Michael J; Duan, Xiaolian

    2013-01-01

    Developing and implementing a set of personal health device interoperability standards is key to cultivating a healthy global industry ecosystem. The standardization organizations, including the Institute of Electrical and Electronics Engineers 11073 Personal Health Device Workgroup (IEEE 11073-PHD WG) and Continua Health Alliance, are striving for this purpose. However, factors like the medial device regulation, health policy, and market reality have placed non-technical barriers over the ad...

  4. Grænser, barrierer og broer

    DEFF Research Database (Denmark)

    Nortvig, Anne Mette; Christiansen, René B.; Karlsen, Asgjerd Vea

    2015-01-01

    ledelsesmæssige muligheder for, at skoleklasser i grundskolen kan arbejde sammen og lære på tværs af de tre landes grænser. Nogle af de helt overordnede mål for projektet har således været at udvikle grænseoverskridende undervisningsmodeller i Norden, der kunne mindske de mentale og praktiske barrierer for en...

  5. Sub-barrier fusion: An experimental review

    International Nuclear Information System (INIS)

    Betts, R.R.

    1991-01-01

    This paper contains a review of the current status of the experimental study of heavy-ion fusion at sub-barrier energies. Emphasis is placed on the comparison of the experimentally observed quantities with theoretical expectations. Results of measurements of the spin distributions of the composite systems formed following fusion are critically examined with a view to understanding the large discrepancies between theory and experiment which exist for some systems. 20 refs., 14 figs

  6. Barriers to Clinical Research in Latin America

    OpenAIRE

    Chomsky-Higgins, Kathryn; Miclau, Theodore A.; Mackechnie, Madeline C.; Aguilar, Dino; Avila, Jorge Rubio; dos Reis, Fernando Baldy; Balmaseda, Roberto; Barquet, Antonio; Ceballos, Alfredo; Contreras, Fernando; Escalante, Igor; Elias, Nelson; Vincenti, Sergio Iriarte; Lozano, Christian; Medina, Fryda

    2017-01-01

    Enhancing health research capacity in developing countries is a global health priority. Understanding the orthopedic burden of disease in Latin America will require close partnership between more-developed and less-developed countries. To this end, the Osteosynthesis and Trauma Care Foundation assembled a research consortium of Latin-American orthopedic leaders. Prior to the meeting, we surveyed attendees on perceived barriers to conducting research at their institutions. During the event, wo...

  7. Plasma measurements with surface barrier detectors

    International Nuclear Information System (INIS)

    Futch, A.H. Jr.; Bradley, A.E.

    1969-01-01

    A surface barrier detector system for measuring the loss rate of protons from a hydrogen plasma and their energy spectrum is described. A full width at half maximum (FWHM) resolution of 1.4 keV for 15-keV hydrogen atoms was obtained using a selected detector having a sensitive area of 3 mm 2 and a depletion depth of 700 microns

  8. Engineered Barrier System: Physical and Chemical Environment

    Energy Technology Data Exchange (ETDEWEB)

    P. Dixon

    2004-04-26

    The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

  9. Disease management programs: barriers and benefits.

    Science.gov (United States)

    Magnezi, Racheli; Kaufman, Galit; Ziv, Arnona; Kalter-Leibovici, Ofra; Reuveni, Haim

    2013-04-01

    The healthcare system in Israel faces difficulties similar to those of most industrialized countries, including limited resources, a growing chronically ill population, and demand for high quality care. Disease management programs (DMPs) for patients with a chronic illness aim to alleviate some of these problems, primarily by improving patient self-management skills and quality of care. This study surveyed the opinions of senior healthcare administrators regarding barriers, benefits, and support for implementing DMPs. Cross-sectional survey. A 21-item questionnaire was self-completed by 87 of 105 (83%) healthcare administrators included in the study. Participants were 65.5% male and 47% physicians, 25.3% nurses, 17.3% administrators, and 10.3% other healthcare professionals. The main perceived benefit of DMPs among all respondents was improving quality of care. Other benefits noted were better contact with patients (81.6%) and better compliance with treatment (75.9%). Efficient long-term utilization of system resources was perceived as a benefit by only 58.6%. The main perceived barriers to implementing DMPs were lack of budgetary resources (69%) and increased time required versus financial compensation received (63.2%). The benefits of DMPs were patient oriented; barriers were perceived as financial and limiting professional autonomy. Information regarding long-term benefits (better patient outcomes) that ultimately provide better value for the system versus short-term barriers (increased costs and expenditures of time without compensation) might encourage the implementation of DMPs in countries faced with a growing population of patients with at least 1 chronic illness.

  10. Reconsolidated Salt as a Geotechnical Barrier

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Francis D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gadbury, Casey [USDOE Carlsbad Field Office, NM (United States)

    2015-11-01

    Salt as a geologic medium has several attributes favorable to long-term isolation of waste placed in mined openings. Salt formations are largely impermeable and induced fractures heal as stress returns to equilibrium. Permanent isolation also depends upon the ability to construct geotechnical barriers that achieve nearly the same high-performance characteristics attributed to the native salt formation. Salt repository seal concepts often include elements of reconstituted granular salt. As a specific case in point, the Waste Isolation Pilot Plant recently received regulatory approval to change the disposal panel closure design from an engineered barrier constructed of a salt-based concrete to one that employs simple run-of-mine salt and temporary bulkheads for isolation from ventilation. The Waste Isolation Pilot Plant is a radioactive waste disposal repository for defense-related transuranic elements mined from the Permian evaporite salt beds in southeast New Mexico. Its approved shaft seal design incorporates barrier components comprising salt-based concrete, bentonite, and substantial depths of crushed salt compacted to enhance reconsolidation. This paper will focus on crushed salt behavior when applied as drift closures to isolate disposal rooms during operations. Scientific aspects of salt reconsolidation have been studied extensively. The technical basis for geotechnical barrier performance has been strengthened by recent experimental findings and analogue comparisons. The panel closure change was accompanied by recognition that granular salt will return to a physical state similar to the halite surrounding it. Use of run-of-mine salt ensures physical and chemical compatibility with the repository environment and simplifies ongoing disposal operations. Our current knowledge and expected outcome of research can be assimilated with lessons learned to put forward designs and operational concepts for the next generation of salt repositories. Mined salt

  11. Reconsolidated Salt as a Geotechnical Barrier

    International Nuclear Information System (INIS)

    Hansen, Francis D.; Gadbury, Casey

    2015-01-01

    Salt as a geologic medium has several attributes favorable to long-term isolation of waste placed in mined openings. Salt formations are largely impermeable and induced fractures heal as stress returns to equilibrium. Permanent isolation also depends upon the ability to construct geotechnical barriers that achieve nearly the same high-performance characteristics attributed to the native salt formation. Salt repository seal concepts often include elements of reconstituted granular salt. As a specific case in point, the Waste Isolation Pilot Plant recently received regulatory approval to change the disposal panel closure design from an engineered barrier constructed of a salt-based concrete to one that employs simple run-of-mine salt and temporary bulkheads for isolation from ventilation. The Waste Isolation Pilot Plant is a radioactive waste disposal repository for defense-related transuranic elements mined from the Permian evaporite salt beds in southeast New Mexico. Its approved shaft seal design incorporates barrier components comprising salt-based concrete, bentonite, and substantial depths of crushed salt compacted to enhance reconsolidation. This paper will focus on crushed salt behavior when applied as drift closures to isolate disposal rooms during operations. Scientific aspects of salt reconsolidation have been studied extensively. The technical basis for geotechnical barrier performance has been strengthened by recent experimental findings and analogue comparisons. The panel closure change was accompanied by recognition that granular salt will return to a physical state similar to the halite surrounding it. Use of run-of-mine salt ensures physical and chemical compatibility with the repository environment and simplifies ongoing disposal operations. Our current knowledge and expected outcome of research can be assimilated with lessons learned to put forward designs and operational concepts for the next generation of salt repositories. Mined salt

  12. Fruit and vegetable consumption: benefits and barriers.

    Science.gov (United States)

    Maclellan, Debbie L; Gottschall-Pass, Katherine; Larsen, Roberta

    2004-01-01

    Few people on Prince Edward Island meet the goal of consuming five or more servings of vegetables and fruit a day. The main objective of this qualitative study was to explore the perceptions of the nutritional benefits and barriers to vegetable and fruit intake among adult women in Prince Edward Island. Participants were 40 women aged 20-49, with or without children at home, who were or were not currently meeting the objective of eating five or more fruit and vegetable servings a day. In-home, one-on-one interviews were used for data collection. Thematic analysis was conducted on the transcribed interviews. Data were examined for trustworthiness in the context of credibility, transferability, and dependability. Most participants identified one or more benefits of eating fruit and vegetables; however, comments tended to be non-specific. The main barriers that participants identified were effort, lack of knowledge, sociopsychological and socioenvironmental factors, and availability. Internal influences, life events, and food rules were identified as encouraging women to include vegetables and fruit in their diets. Given the challenges of effecting meaningful dietary change, dietitians must look for broader dietary behavioural interventions that are sensitive to women's perceptions of benefits and barriers to fruit and vegetable intake.

  13. Regulatory barriers blocking standardization of interoperability.

    Science.gov (United States)

    Zhong, Daidi; Kirwan, Michael J; Duan, Xiaolian

    2013-07-12

    Developing and implementing a set of personal health device interoperability standards is key to cultivating a healthy global industry ecosystem. The standardization organizations, including the Institute of Electrical and Electronics Engineers 11073 Personal Health Device Workgroup (IEEE 11073-PHD WG) and Continua Health Alliance, are striving for this purpose. However, factors like the medial device regulation, health policy, and market reality have placed non-technical barriers over the adoption of technical standards throughout the industry. These barriers have significantly impaired the motivations of consumer device vendors who desire to enter the personal health market and the overall success of personal health industry ecosystem. In this paper, we present the affect that these barriers have placed on the health ecosystem. This requires immediate action from policy makers and other stakeholders. The current regulatory policy needs to be updated to reflect the reality and demand of consumer health industry. Our hope is that this paper will draw wide consensus amongst its readers, policy makers, and other stakeholders.

  14. The barrier within: endothelial transport of hormones.

    Science.gov (United States)

    Kolka, Cathryn M; Bergman, Richard N

    2012-08-01

    Hormones are involved in a plethora of processes including development and growth, metabolism, mood, and immune responses. These essential functions are dependent on the ability of the hormone to access its target tissue. In the case of endocrine hormones that are transported through the blood, this often means that the endothelium must be crossed. Many studies have shown that the concentrations of hormones and nutrients in blood can be very different from those surrounding the cells on the tissue side of the blood vessel endothelium, suggesting that transport across this barrier can be rate limiting for hormone action. This transport can be regulated by altering the surface area of the blood vessel available for diffusion through to the underlying tissue or by the permeability of the endothelium. Many hormones are known to directly or indirectly affect the endothelial barrier, thus affecting their own distribution to their target tissues. Dysfunction of the endothelial barrier is found in many diseases, particularly those associated with the metabolic syndrome. The interrelatedness of hormones may help to explain why the cluster of diseases in the metabolic syndrome occur together so frequently and suggests that treating the endothelium may ameliorate defects in more than one disease. Here, we review the structure and function of the endothelium, its contribution to the function of hormones, and its involvement in disease.

  15. Healthcare barriers of refugees post-resettlement.

    Science.gov (United States)

    Morris, Meghan D; Popper, Steve T; Rodwell, Timothy C; Brodine, Stephanie K; Brouwer, Kimberly C

    2009-12-01

    The majority of refugees spend the greater part of their lives in refugee camps before repatriation or resettlement to a host country. Limited resources and stress during residence in refugee camps can lead to a variety of acute and chronic diseases which often persist upon resettlement. However, for most resettled refugees little is known about their health needs beyond a health assessment completed upon entry. We conducted a qualitative pilot-study in San Diego County, the third largest area in California, USA for resettling refugees, to explore health care access issues of refugees after governmental assistance has ended. A total of 40 guided in-depth interviews were conducted with a targeted sample of informants (health care practitioners, employees of refugee serving organizations, and recent refugee arrivals) familiar with the health needs of refugees. Interviews revealed that the majority of refugees do not regularly access health services. Beyond individual issues, emerging themes indicated that language and communication affect all stages of health care access--from making an appointment to filling out a prescription. Acculturation presented increased stress, isolation, and new responsibilities. Additionally, cultural beliefs about health care directly affected refugees' expectation of care. These barriers contribute to delayed care and may directly influence refugee short- and long-term health. Our findings suggest the need for additional research into contextual factors surrounding health care access barriers, and the best avenues to reduce such barriers and facilitate access to existing services.

  16. ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    R. Jarek

    2004-11-23

    The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports.

  17. Barriers and enablers to academic health leadership.

    Science.gov (United States)

    Bharwani, Aleem; Kline, Theresa; Patterson, Margaret; Craighead, Peter

    2017-02-06

    Purpose This study sought to identify the barriers and enablers to leadership enactment in academic health-care settings. Design/methodology/approach Semi-structured interviews ( n = 77) with programme stakeholders (medical school trainees, university leaders, clinical leaders, medical scientists and directors external to the medical school) were conducted, and the responses content-analysed. Findings Both contextual and individual factors were identified as playing a role in affecting academic health leadership enactment that has an impact on programme development, success and maintenance. Contextual factors included sufficient resources allocated to the programme, opportunities for learners to practise leadership skills, a competent team around the leader once that person is in place, clear expectations for the leader and a culture that fosters open communication. Contextual barriers included highly bureaucratic structures, fear-of-failure and non-trusting cultures and inappropriate performance systems. Programmes were advised to select participants based on self-awareness, strong communication skills and an innovative thinking style. Filling specific knowledge and skill gaps, particularly for those not trained in medical school, was viewed as essential. Ineffective decision-making styles and tendencies to get involved in day-to-day activities were barriers to the development of academic health leaders. Originality/value Programmes designed to develop academic health-care leaders will be most effective if they develop leadership at all levels; ensure that the organisation's culture, structure and processes reinforce positive leadership practices; and recognise the critical role of teams in supporting its leaders.

  18. Regulatory barriers to hazardous waste technology innovation

    International Nuclear Information System (INIS)

    Kuusinen, T.L.; Siegel, M.R.

    1991-02-01

    The primary federal regulatory programs that influence the development of new technology for hazardous waste are the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA, also commonly known as Superfund). Two important aspects of RCRA that can create barriers to hazardous waste technology innovation are technology-based waste pre-treatment standards and a cumbersome permitting program. By choosing a technology-based approach to the RCRA land disposal restrictions program, the US Environmental Protection Agency (EPA) has simultaneously created tremendous demand for the technologies specified in its regulations, while at the same time significantly reduced incentives for technology innovation that might have otherwise existed. Also, the RCRA hazardous waste permitting process can take years and cost hundreds of thousands of dollars. The natural tendency of permit writers to be cautious of unproven (i.e., innovative) technology also can create a barrier to deployment of new technologies. EPA has created several permitting innovations, however, to attempt to mitigate this latter barrier. Understanding the constraints of these permitting innovations can be important to the success of hazardous waste technology development programs. 3 refs

  19. Barrier Coatings for Refractory Metals and Superalloys

    International Nuclear Information System (INIS)

    SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

    2006-01-01

    In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life

  20. Motivators and barriers for paediatricians discharging patients.

    Science.gov (United States)

    Turbitt, Erin; Kunin, Marina; Gafforini, Sarah; Freed, Gary L

    2017-07-01

    The aim of this study was to identify motivators and barriers that paediatricians face when discharging patients from outpatient specialty care. A questionnaire was administered to outpatient care paediatricians in Victoria working in one of five speciality public hospital clinics. Questions focused on how important various motivators and barriers were in respondents' decision to discharge a patient from their clinic. Nearly all (91%, n=74) paediatricians invited to participate provided responses. The factor influencing the greatest proportion of paediatricians in their decision to discharge patients back to primary care was the potential that patients may not receive the required care from a GP. The next most highly rated barrier was that it is too complicated to arrange discharge; rated as a very important influence by one-third of paediatricians (33%, n=24). Improvements to the discharge process may encourage more paediatricians to discharge patients back to their GP, therefore freeing up appointment slots. This in turn could reduce waiting times for paediatric outpatient clinics in Victoria. The concern from paediatricians that patients may not receive the required care from a GP warrants attention and should be further investigated.

  1. TMX-U thermal-barrier experiments

    International Nuclear Information System (INIS)

    Simonen, T.C.; Allen, S.L.; Barter, J.D.

    1988-01-01

    This review of thermal-barrier experiments in the Tandem Mirror Experiment Upgrade (TMX-U) describes our progress at Lawrence Livermore National Laboratory in plasma confinement and central-cell heating. Thermal barriers in TMX-U improved axial confinement by two orders of magnitude over a limited range of densities, compared with confinement in single-cell mirrors at the same ion temperature. Our study shows that central-cell radial nonambipolar confinement scales as neoclassical theory and can be eliminated by floating the end walls. Radial ambipolar losses can also be measured and reduced. The electron energy balance is improved in tandem mirrors to near classical, resulting in T/sub e/ up to 0.28 keV. Electron cyclotron heating (ECH) efficiencies up to 42 percent, with low levels of electron microinstability, were achieved when hot electrons in the thermal barrier were heated to average betas as large as 15 percent. The hot-electron distribution is measured from X rays and is modeled by a Fokker-Planck code that includes heating from cavity radio-frequency (RF) fields. Neutral-beam injection in the central cell created average ion betas up to 5 percent with radial profiles of hot ions that are modeled accurately by a radial Fokker-Planck code. Gas fueling between two fundamental ion cyclotron heating (ICH) resonances resulted in symmetrical heating of passing ions toward both ends

  2. Barrier Coatings for Refractory Metals and Superalloys

    Energy Technology Data Exchange (ETDEWEB)

    SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close

    2006-02-23

    In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life.

  3. Use of Postpartum Care: Predictors and Barriers

    Directory of Open Access Journals (Sweden)

    Jessica N. DiBari

    2014-01-01

    Full Text Available This study aimed to identify actual and perceived barriers to postpartum care among a probability sample of women who gave birth in Los Angeles County, California in 2007. Survey data from the 2007 Los Angeles Mommy and Baby (LAMB study (N = 4,075 were used to identify predictors and barriers to postpartum care use. The LAMB study was a cross-sectional, population-based study that examined maternal and child health outcomes during the preconception, prenatal, and postpartum periods. Multivariable analyses identified low income, being separated/divorced and never married, trying hard to get pregnant or trying to prevent pregnancy, Medi-Cal insurance holders, and lack of prenatal care to be risk factors of postpartum care nonuse, while Hispanic ethnicity was protective. The most commonly reported barriers to postpartum care use were feeling fine, being too busy with the baby, having other things going on, and a lack of need. Findings from this study can inform the development of interventions targeting subgroups at risk for not obtaining postpartum care. Community education and improved access to care can further increase the acceptability of postpartum visits and contribute to improvements in women’s health. Postpartum care can serve as a gateway to engage underserved populations in the continuum of women’s health care.

  4. Vulnerability of multiple-barrier systems

    International Nuclear Information System (INIS)

    Lind, N.C.

    1996-01-01

    'Vulnerability' is defined as the ratio of the probability of failure of a damaged system to the probability of failure of the undamaged system. This definition applies to all engineered systems and can be specialized to particular system types. Some disastrous failures (e.g., Chernobyl) have shown that systems can be highly vulnerable. open-quotes Defense in depthclose quotes is a powerful design principle, reducing vulnerability when the consequences of failure can be catastrophic. In the nuclear industry, defense in depth is widely used in radiation protection, reactor control, and shutdown systems. A multiple-barrier system is a simple example of a system that has defense in depth. The idea is that the system is not vulnerable. It cannot fail if one barrier fails because there is another to take its place. This idea is untenable in waste management, but a quantified vulnerability of a system can help owners, designers, and regulators decide how much defense in depth is desirable or enough. Many multiple-barrier systems can be modeled as systems of components physically in a series, each individually able to prevent failure. Components typically have bimodal distributions of the service time to failure, as illustrated by an example of application to a hypothetical nuclear fuel waste repository

  5. Charge transport through DNA based electronic barriers

    Science.gov (United States)

    Patil, Sunil R.; Chawda, Vivek; Qi, Jianqing; Anantram, M. P.; Sinha, Niraj

    2018-05-01

    We report charge transport in electronic 'barriers' constructed by sequence engineering in DNA. Considering the ionization potentials of Thymine-Adenine (AT) and Guanine-Cytosine (GC) base pairs, we treat AT as 'barriers'. The effect of DNA conformation (A and B form) on charge transport is also investigated. Particularly, the effect of width of 'barriers' on hole transport is investigated. Density functional theory (DFT) calculations are performed on energy minimized DNA structures to obtain the electronic Hamiltonian. The quantum transport calculations are performed using the Landauer-Buttiker framework. Our main findings are contrary to previous studies. We find that a longer A-DNA with more AT base pairs can conduct better than shorter A-DNA with a smaller number of AT base pairs. We also find that some sequences of A-DNA can conduct better than a corresponding B-DNA with the same sequence. The counterions mediated charge transport and long range interactions are speculated to be responsible for counter-intuitive length and AT content dependence of conductance of A-DNA.

  6. Vibration behavior of the artificial barrier system

    International Nuclear Information System (INIS)

    Mikoshiba, Tadashi; Ogawa, Nobuyuki; Nakamura, Izuru

    2000-01-01

    This study aims at production of a mimic specimen of artificial barrier, experimental elucidation of influence of seismic motion due to a vibration experiment on the artificial barrier system, and establishment of an evaluating method on its long-term behavior. The study has been carried out under a cooperative study of the National Research Institute for Earth Science and Disaster Prevention and the Japan Nuclear Cycle Development Institute. In 1998 fiscal year, an artificial barrier specimen initiated by crosscut road was produced, and their random wave and actual seismic wave vibrations were carried out to acquire their fundamental data. As a result of the both vibrations, it was found that in a Case 2 specimen of which buffer material was swelled by poured water, the material was integrated with a mimic over-pack to vibrate under judgement of eigen-frequency, maximum acceleration ratio, and so forth on the test results. And, in a Case 1 specimen, it was thought that the mimic over-pack showed an extreme non-linear performance (soft spring) because of reducing eigen-frequency with increase of its vibration level. (G.K.)

  7. ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

    International Nuclear Information System (INIS)

    Jarek, R.

    2004-01-01

    The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports

  8. ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

    International Nuclear Information System (INIS)

    G.H. Nieder-Westermann

    2005-01-01

    The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports

  9. Vibration behavior of the artificial barrier system

    Energy Technology Data Exchange (ETDEWEB)

    Mikoshiba, Tadashi; Ogawa, Nobuyuki; Nakamura, Izuru [National Research Inst. for Earth sceince and Disaster Prevention (Japan)

    2000-02-01

    This study aims at production of a mimic specimen of artificial barrier, experimental elucidation of influence of seismic motion due to a vibration experiment on the artificial barrier system, and establishment of an evaluating method on its long-term behavior. The study has been carried out under a cooperative study of the National Research Institute for Earth Science and Disaster Prevention and the Japan Nuclear Cycle Development Institute. In 1998 fiscal year, an artificial barrier specimen initiated by crosscut road was produced, and their random wave and actual seismic wave vibrations were carried out to acquire their fundamental data. As a result of the both vibrations, it was found that in a Case 2 specimen of which buffer material was swelled by poured water, the material was integrated with a mimic over-pack to vibrate under judgement of eigen-frequency, maximum acceleration ratio, and so forth on the test results. And, in a Case 1 specimen, it was thought that the mimic over-pack showed an extreme non-linear performance (soft spring) because of reducing eigen-frequency with increase of its vibration level. (G.K.)

  10. ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    G.H. Nieder-Westermann

    2005-04-07

    The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports.

  11. Zero Learning: Case explorations of barriers to organizational learning

    DEFF Research Database (Denmark)

    Jørgensen, Frances; S., Jacob

    2003-01-01

    that the existence of learning barriers may not only inhibit on-going learning process, but also lead to a negative cycle of non-learning in the organization. The implications of a "zero learning" cycle caused by learning barriers are discussed and insights are provided as to how barriers may be resolved so...

  12. A Survey to Assess Barriers to Urban Teaching Careers

    Science.gov (United States)

    Creasey, Gary; Mays, Jennifer; Lee, Robert; D'Santiago, Verenice

    2016-01-01

    The "Urban Teaching Barriers" survey was created to assess barriers to urban teaching careers. Pre-service teachers (N = 377) completed this instrument, along with questionnaires that assessed urban teaching intentions and urban teaching self-efficacy. Six barrier domains were identified that tapped concerns over (a) lack of resources,…

  13. Barriers and strategies for innovations entering BoP markets

    NARCIS (Netherlands)

    Kamp, L.M.; Ortt, J.R.; Harahap, B.

    2015-01-01

    Companies that bring a new product to the market or enter a new market with an existing product, come across a number of barriers that prevent large?scale diffusion. In order to circumvent or remove these barriers, they can adopt alternative strategies. This paper looks into these barriers and

  14. SME's perceptions regarding strategic and structural entry barriers

    NARCIS (Netherlands)

    Lutz, Clemens; Kemp, Ron; Dijkstra, S. Gerhard

    2007-01-01

    Abstract Extant literature discusses a large number of different entry barriers that may hamper market efficiency or entrepreneurial activity. In practice several of these barriers cohere and stem from the same root. Factor analysis is used to identify the underlying dimensions of these barriers. 7

  15. Patients' reports of barriers to expressing concerns during cancer consultations.

    Science.gov (United States)

    Brandes, Kim; Linn, Annemiek J; Smit, Edith G; van Weert, Julia C M

    2015-03-01

    To identify cancer patients' most influential barriers to expressing concerns during cancer consultations in a new manner by examining patients' reports of perceived barriers and perceived occurrence of barriers in consultations. Two online focus groups (N=16) and an online survey (N=236) were conducted among cancer patients and cancer survivors. The online focus groups and survey were used to examine two elements of patients' barriers, i.e., patients' reports of perceived barriers and perceived occurrence of barriers in consultations. Composite scores of these two elements were calculated to determine influential barriers. Results showed that the most influential barriers were related to providers' behavior (e.g., providers do not explicitly invite patients to express concerns) and the environment where the consultation takes place (e.g., perceived lack of time). The results of this study indicate that influential barriers to expressing concerns are barriers that patients cannot overcome themselves (i.e., they are related to providers' behavior or the environment of the consultation). A collaborative approach between researchers, providers and policy makers is needed to overcome these barriers. The results of this study can be used to develop strategies to overcome barriers to patients expressing concerns. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  16. Origin of methyl torsional potential barrier – An overview

    Indian Academy of Sciences (India)

    Unknown

    The effect of skeletal flexing on the picture of barrier .... views to explain the origin of the barrier to this rotation have been proposed, but none of .... molecule, a model is always advantageous to predict the barrier and its cause in a given.

  17. Overcoming Branding Barriers in Nonprofit, Private Colleges and Universities

    Science.gov (United States)

    Chyr, Fred

    2017-01-01

    Purpose: The purpose of this Delphi study was to explore the views of experts in the field of nonprofit private colleges and universities in the United States to define branding and identify current barriers to branding, to discover how those barriers can be overcome, and to determine what barriers to branding are likely to occur 5 years in the…

  18. Classification of paraglacial barrier systems: coastal New England, USA.

    NARCIS (Netherlands)

    FitzGerald, D.M.; van Heteren, S.

    1999-01-01

    The New England coast harbours a wide variety of barrier forms, which we organize into six barrier-coastline types. The barriers develop in response to the relative importance of several spatially and temporally variable parameters, particularly antecedent topography and geology, sediment abundance

  19. Barriers to Herbal Medicine Research in Nigeria; Researcher's ...

    African Journals Online (AJOL)

    This paper presents the barriers to herbal medicine research in Nigeria. This is with a view to formulating appropriate strategies that would be deployed to overcome the identified barriers to herbal medicine research. The paper therefore identified and discussed some of these inherent barriers such as the standardization of ...

  20. Gliovascular and cytokine interactions modulate brain endothelial barrier in vitro.

    Science.gov (United States)

    Chaitanya, Ganta V; Cromer, Walter E; Wells, Shannon R; Jennings, Merilyn H; Couraud, P Olivier; Romero, Ignacio A; Weksler, Babette; Erdreich-Epstein, Anat; Mathis, J Michael; Minagar, Alireza; Alexander, J Steven

    2011-11-23

    The glio-vascular unit (G-unit) plays a prominent role in maintaining homeostasis of the blood-brain barrier (BBB) and disturbances in cells forming this unit may seriously dysregulate BBB. The direct and indirect effects of cytokines on cellular components of the BBB are not yet unclear. The present study compares the effects of cytokines and cytokine-treated astrocytes on brain endothelial barrier. 3-dimensional transwell co-cultures of brain endothelium and related-barrier forming cells with astrocytes were used to investigate gliovascular barrier responses to cytokines during pathological stresses. Gliovascular barrier was measured using trans-endothelial electrical resistance (TEER), a sensitive index of in vitro barrier integrity. We found that neither TNF-α, IL-1β or IFN-γ directly reduced barrier in human or mouse brain endothelial cells or ECV-304 barrier (independent of cell viability/metabolism), but found that astrocyte exposure to cytokines in co-culture significantly reduced endothelial (and ECV-304) barrier. These results indicate that the barrier established by human and mouse brain endothelial cells (and other cells) may respond positively to cytokines alone, but that during pathological conditions, cytokines dysregulate the barrier forming cells indirectly through astrocyte activation involving reorganization of junctions, matrix, focal adhesion or release of barrier modulating factors (e.g. oxidants, MMPs). © 2011 Chaitanya et al; licensee BioMed Central Ltd.

  1. 10 CFR 63.115 - Requirements for multiple barriers.

    Science.gov (United States)

    2010-01-01

    ... Requirements for multiple barriers. Demonstration of compliance with § 63.113(a) must: (a) Identify those design features of the engineered barrier system, and natural features of the geologic setting, that are... 10 Energy 2 2010-01-01 2010-01-01 false Requirements for multiple barriers. 63.115 Section 63.115...

  2. Partitioning of methyl internal rotational barrier energy of ...

    Indian Academy of Sciences (India)

    The nature of methyl internal rotational barrier in thioacetaldehyde has been investigated by relaxation effect, natural bond orbital (NBO) analysis and Pauling exchange interactions. The true experimental barrier can be obtained by considering fully relaxed rotation. Nuclear-electron attraction term is a barrier forming term in ...

  3. Perceived Career Barriers for Gay, Lesbian, and Bisexual Individuals

    Science.gov (United States)

    Parnell, Martha Keeton; Lease, Suzanne H.; Green, Michael L.

    2012-01-01

    This study examined career-related barriers that gay, lesbian, and bisexual (GLB) individuals had encountered in the past and anticipated in the future and the degree of hindrance associated with future barriers. Two hundred forty-one GLB participants (126 women and 115 men) completed the Career Barriers Inventory-Revised and 11 additional items…

  4. An oncological view on the blood-testis barrier

    NARCIS (Netherlands)

    Bart, J; Groen, HJM; van der Graaf, WTA; Hollema, H; Hendrikse, NH; Vaalburg, W; Sleijfer, DT; de Vries, EGE

    The function of the blood-testis barrier is to protect germ cells from harmful influences; thus, it also impedes the delivery of chemotherapeutic drugs to the testis. The barrier has three components: first, a physicochemical barrier consisting of continuous capillaries, Sertoli cells in the tubular

  5. Psychology of Success: Overcoming Barriers to Pursuing Further Education

    Science.gov (United States)

    Goto, Stanford T.; Martin, Connie

    2009-01-01

    Of the many barriers that prevent adults from continuing their education, psychological barriers are least often addressed by educators. This is an important area of concern because psychological factors influence how prospective students respond to other barriers. This qualitative study was conducted to describe how adults negotiate…

  6. Legal and Regulatory Barriers to Reverse Innovation.

    Science.gov (United States)

    Rowthorn, Virginia; Plum, Alexander J; Zervos, John

    Reverse innovation, or the importation of new, affordable, and efficacious models to high-income countries from the developing world, has emerged as a way to improve the health care system in the United States. Reverse innovation has been identified as a key emerging trend in global health systems in part because low-resourced settings are particularly good laboratories for low-cost/high-impact innovations that are developed out of necessity. A difficult question receiving scant attention is that of legal and regulatory barriers. The objective of this paper is to understand and elucidate the legal barriers faced by innovators bringing health interventions to the United States. Semistructured qualitative interviews were conducted with 9 key informants who have directly participated in the introduction of global health care approaches to the United States health system. A purposive sampling scheme was employed to identify participants. Phone interviews were conducted over one week in July 2016 with each participant and lasted an average of 35 minutes each. Purely legal barriers included questions surrounding tort liability, standard of care, and concerns around patient-administered self-care. Regulatory burdens included issues of international medical licensure, reimbursement, and task shifting and scope of work challenges among nonprofessionals (e.g. community health workers). Finally, perceived (i.e. not realized or experienced) legal and regulatory barriers to innovative modalities served as disincentives to bringing products or services developed outside of the United States to the United States market. Conflicting interests within the health care system, safety concerns, and little value placed on low-cost interventions inhibit innovation. Legal and regulatory barriers rank among, and contribute to, an anti-innovation atmosphere in healthcare for domestic and reverse innovators alike. Reverse innovation should be fostered through the thoughtful development of

  7. Thermal barrier coatings application in diesel engines

    Science.gov (United States)

    Fairbanks, J. W.

    1995-01-01

    Commercial use of thermal barrier coatings in diesel engines began in the mid 70's by Dr. Ingard Kvernes at the Central Institute for Industrial Research in Oslo, Norway. Dr. Kvernes attributed attack on diesel engine valves and piston crowns encountered in marine diesel engines in Norwegian ships as hot-corrosion attributed to a reduced quality of residual fuel. His solution was to coat these components to reduce metal temperature below the threshold of aggressive hot-corrosion and also provide protection. Roy Kamo introduced thermal barrier coatings in his 'Adiabatic Diesel Engine' in the late 70's. Kamo's concept was to eliminate the engine block water cooling system and reduce heat losses. Roy reported significant performance improvements in his thermally insulated engine at the SAE Congress in 1982. Kamo's work stimulates major programs with insulated engines, particularly in Europe. Most of the major diesel engine manufacturers conducted some level of test with insulated combustion chamber components. They initially ran into increased fuel consumption. The German engine consortium had Prof. Woschni of the Technical Institute in Munich. Woschni conducted testing with pistons with air gaps to provide the insulation effects. Woschni indicated the hot walls of the insulated engine created a major increase in heat transfer he refers to as 'convection vive.' Woschni's work was a major factor in the abrupt curtailment of insulated diesel engine work in continental Europe. Ricardo in the UK suggested that combustion should be reoptimized for the hot-wall effects of the insulated combustion chamber and showed under a narrow range of conditions fuel economy could be improved. The Department of Energy has supported thermal barrier coating development for diesel engine applications. In the Clean Diesel - 50 Percent Efficient (CD-50) engine for the year 2000, thermal barrier coatings will be used on piston crowns and possibly other components. The primary purpose of the

  8. Barriers to Participation in Parenting Programs: The Relationship between Parenting Stress, Perceived Barriers, and Program Completion.

    Science.gov (United States)

    Rostad, Whitney L; Moreland, Angela D; Valle, Linda Anne; Chaffin, Mark J

    2018-04-01

    Families experiencing child maltreatment or risk factors for child maltreatment often receive referrals to interventions focused on changing parenting practices. Compliance with specific parenting programs can be challenging as many of the stressors that place families at-risk may also interfere with program participation. Because families may receive limited benefit from programs they do not fully receive, it is critical to understand the relationship between parenting stress and barriers to program completion. We used structural equation modeling to examine the relationship among parenting stress, perceived barriers to program participation, and program completion in two datasets involving low-income parents. Data were collected at two time points from a sample of parents involved with child welfare services and a sample of parents considered at-risk of future involvement (total study n = 803). Direct paths from parenting stress at time 1 to barriers to participation and parenting stress at time 2, and from parenting stress at time 2 to program completion were significant. Interestingly, increased barriers to participation were related to increased parenting stress at time 2, and greater parenting stress was related to increased program completion. Results suggest that with increasing levels of parenting stress, parents have an increased likelihood of completing the program. Assessing and addressing the influence of perceived barriers and parenting stress on program participation may decrease the likelihood of treatment attrition.

  9. Barriers to participation in mental health research: are there specific gender, ethnicity and age related barriers?

    Directory of Open Access Journals (Sweden)

    Howard Louise

    2010-12-01

    Full Text Available Abstract Background It is well established that the incidence, prevalence and presentation of mental disorders differ by gender, ethnicity and age, and there is evidence that there is also differential representation in mental health research by these characteristics. The aim of this paper is to a review the current literature on the nature of barriers to participation in mental health research, with particular reference to gender, age and ethnicity; b review the evidence on the effectiveness of strategies used to overcome these barriers. Method Studies published up to December 2008 were identified using MEDLINE, PsycINFO and EMBASE using relevant mesh headings and keywords. Results Forty-nine papers were identified. There was evidence of a wide range of barriers including transportation difficulties, distrust and suspicion of researchers, and the stigma attached to mental illness. Strategies to overcome these barriers included the use of bilingual staff, assistance with travel, avoiding the use of stigmatising language in marketing material and a focus on education about the disorder under investigation. There were very few evaluations of such strategies, but there was evidence that ethnically matching recruiters to potential participants did not improve recruitment rates. Educational strategies were helpful and increased recruitment. Conclusion Mental health researchers should consider including caregivers in recruitment procedures where possible, provide clear descriptions of study aims and describe the representativeness of their sample when reporting study results. Studies that systematically investigate strategies to overcome barriers to recruitment are needed.

  10. The blood-tendon barrier: identification and characterisation of a novel tissue barrier in tendon blood vessels

    Directory of Open Access Journals (Sweden)

    C Lehner

    2016-05-01

    Full Text Available Tissue barriers function as “gate keepers” between different compartments (usually blood and tissue and are formed by specialised membrane-associated proteins, localising to the apicolateral plasma membrane domain of epithelial and endothelial cells. By sealing the paracellular space, the free diffusion of solutes and molecules across epithelia and endothelia is impeded. Thereby, tissue barriers contribute to the establishment and maintenance of a distinct internal and external environment, which is crucial during organ development and allows maintenance of an organ-specific homeostatic milieu. So far, various epithelial and endothelial tissue barriers have been described, including the blood-brain barrier, the blood-retina barrier, the blood-testis barrier, the blood-placenta barrier, and the cerebrospinal fluid (CSF-brain barrier, which are vital for physiological function and any disturbance of these barriers can result in severe organ damage or even death. Here, we describe the identification of a novel barrier, located in the vascular bed of tendons, which we term the blood-tendon barrier (BTB. By using immunohistochemistry, transmission electron microscopy, and tracer studies we demonstrate the presence of a functional endothelial barrier within tendons restricting the passage of large blood-borne molecules into the surrounding tendon tissue. We further provide in vitro evidence that the BTB potentially contributes to the creation of a distinct internal tissue environment impacting upon the proliferation and differentiation of tendon-resident cells, effects which might be fundamental for the onset of tendon pathologies.

  11. Spin-dependent dwell time through ferromagnetic graphene barrier

    International Nuclear Information System (INIS)

    Sattari, F.

    2014-01-01

    We investigated the dwell time of electrons tunneling through a ferromagnetic (FM) graphene barrier. The results show that the spin polarization can be efficiently controlled by the barrier width, barrier height, and the incident electron energy. Furthermore, it is found that electrons with different spin orientations will spend different times through the barrier. The difference of the dwell time between spin-up and spin-down electrons arises from the exchange splitting, which is induced by the FM strip. Study results indicate that a ferromagnetic graphene barrier can cause a nature spin filter mechanism in the time domain

  12. Barriers to Physical Activity in Individuals with Spinal Cord Injury

    DEFF Research Database (Denmark)

    Roberton, Terri; Bucks, Romola S.; Skinner, Timothy C.

    2011-01-01

    This study examined barriers to physical activity reported individuals with spinal cord injury (SCI) and the degree to which these barriers differed across varying degrees of independence. Participants were 65 individuals recruited from the Western Australian Spinal Cord Injury database. Data...... on physical activity participation and perceived barriers to physical activity participation were collected using a cross-sectional survey and analysed using independent samples t-tests. We found that, regardless of level of ambulation or ability to transfer, few participants reported being physically active....... While there were no significant differences in the amount of barriers reported by individuals with different levels of independence, the type of barriers reported varied across groups....

  13. Large magnetocurrents in double-barrier tunneling transistors

    International Nuclear Information System (INIS)

    Lee, J.H.; Jun, K.-I.; Shin, K.-H.; Park, S.Y.; Hong, J.K.; Rhie, K.; Lee, B.C.

    2005-01-01

    Magnetic tunneling transistors (MTT) with double tunneling barriers are fabricated. The structure of the transistor is AFM/FM/I/FM/I/FM/AFM, and ferromagnetic layers serve as the emitter, base and collector. This double-barrier tunneling transistor (DBTT) has an advantage of controlling the potential between the base and collector, compared to the Schottky-barrier-based base and collector of MTT. We found that the collector current density of DBTT is at least 10 3 times larger than that of conventional MTT, since tunneling through AlO x barrier provides much larger current density than that through Schottky barrier

  14. Permeable bio-reactive barriers for hydrocarbon remediation in Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Mumford, K.A.; Stevens, G.W.; Gore, D.B. [Melbourne Univ., Victoria (Australia). Dept. of Chemical and Biomoleculuar Engineering, Particulate Fluids Processing Centre; Snape, I.; Rayner, J.L. [Australian Antarctic Div., Kingston, Tasmania (Australia); Gore, D.B. [Macquarie Univ., Sydney, NSW (Australia). Dept. of Environmental Science

    2010-07-01

    This study assessed the performance of a permeable bio-reactive barrier designed to treat contaminated water. The bio-reactive barrier was installed at a fuel spill site located in the Windmill Islands, Antarctica. A funnel and gate design was used to prevent contaminant migration beyond the barrier location as well as to ensure controlled nutrient delivery. The study also investigated the performance of the bio-reactive barrier in regions with freeze-thaw conditions. The 4-year project was also conducted to assess optimal conditions for enhancing the barrier's ability to degrade hydrocarbons.

  15. Potential barrier classification by short-time measurement

    International Nuclear Information System (INIS)

    Granot, Er'el; Marchewka, Avi

    2006-01-01

    We investigate the short-time dynamics of a delta-function potential barrier on an initially confined wave packet. There are mainly two conclusions: (A) At short times the probability density of the first particles that passed through the barrier is unaffected by it. (B) When the barrier is absorptive (i.e., its potential is imaginary) it affects the transmitted wave function at shorter times than a real potential barrier. Therefore, it is possible to distinguish between an imaginary and a real potential barrier by measuring its effect at short times only on the transmitting wave function

  16. Potential barrier classification by short-time measurement

    Science.gov (United States)

    Granot, Er'El; Marchewka, Avi

    2006-03-01

    We investigate the short-time dynamics of a delta-function potential barrier on an initially confined wave packet. There are mainly two conclusions: (A) At short times the probability density of the first particles that passed through the barrier is unaffected by it. (B) When the barrier is absorptive (i.e., its potential is imaginary) it affects the transmitted wave function at shorter times than a real potential barrier. Therefore, it is possible to distinguish between an imaginary and a real potential barrier by measuring its effect at short times only on the transmitting wave function.

  17. Control of Internal Transport Barriers in Magnetically Confined Fusion Plasmas

    Science.gov (United States)

    Panta, Soma; Newman, David; Sanchez, Raul; Terry, Paul

    2016-10-01

    In magnetic confinement fusion devices the best performance often involves some sort of transport barriers to reduce the energy and particle flow from core to edge. Those barriers create gradients in the temperature and density profiles. If gradients in the profiles are too steep that can lead to instabilities and the system collapses. Control of these barriers is therefore an important challenge for fusion devices (burning plasmas). In this work we focus on the dynamics of internal transport barriers. Using a simple 7 field transport model, extensively used for barrier dynamics and control studies, we explore the use of RF heating to control the local gradients and therefore the growth rates and shearing rates for barrier initiation and control in self-heated fusion plasmas. Ion channel barriers can be formed in self-heated plasmas with some NBI heating but electron channel barriers are very sensitive. They can be formed in self-heated plasmas with additional auxiliary heating i.e. NBI and radio-frequency(RF). Using RF heating on both electrons and ions at proper locations, electron channel barriers along with ion channel barriers can be formed and removed demonstrating a control technique. Investigating the role of pellet injection in controlling the barriers is our next goal. Work supported by DOE Grant DE-FG02-04ER54741.

  18. Biointrusion test plan for the Permanent Isolation Surface Barrier Prototype

    International Nuclear Information System (INIS)

    Link, S.O.; Cadwell, L.L.; Brandt, C.A.; Downs, J.L.; Rossi, R.E.; Gee, G.W.

    1994-04-01

    This document provides a testing and monitoring plan for the biological component of the prototype barrier slated for construction at the Hanford Site. The prototype barrier is an aboveground structure engineered to demonstrate the basic features of an earthen cover system. It is designed to permanently isolate waste from the biosphere. The features of the barrier include multiple layers of soil and rock materials and a low-permeability asphalt sublayer. The surface of the barrier consists of silt loam soil, covered with plants. The barrier sides are reinforced with rock or coarse earthen-fill to protect against wind and water erosion. The sublayers inhibit plant and animal intrusion and percolation of water. A series of tests will be conducted on the prototype barrier over the next several years to evaluate barrier performance under extreme climatic conditions. Plants and animals will play a significant role in the hydrologic and water and wind erosion characteristics of the prototype barrier. Studies on the biological component of the prototype barrier will include work on the initial revegetation of the surface, continued monitoring of the developing plant community, rooting depth and dispersion in the context of biointrusion potential, the role of plants in the hydrology of the surface and toe regions of the barrier, the role of plants in stabilizing the surface against water and wind erosion, and the role of burrowing animals in the hydrology and water and wind erosion of the barrier

  19. Review of potential subsurface permeable barrier emplacement and monitoring technologies

    International Nuclear Information System (INIS)

    Riggsbee, W.H.; Treat, R.L.; Stansfield, H.J.; Schwarz, R.M.; Cantrell, K.J.; Phillips, S.J.

    1994-02-01

    This report focuses on subsurface permeable barrier technologies potentially applicable to existing waste disposal sites. This report describes candidate subsurface permeable barriers, methods for emplacing these barriers, and methods used to monitor the barrier performance. Two types of subsurface barrier systems are described: those that apply to contamination.in the unsaturated zone, and those that apply to groundwater and to mobile contamination near the groundwater table. These barriers may be emplaced either horizontally or vertically depending on waste and site characteristics. Materials for creating permeable subsurface barriers are emplaced using one of three basic methods: injection, in situ mechanical mixing, or excavation-insertion. Injection is the emplacement of dissolved reagents or colloidal suspensions into the soil at elevated pressures. In situ mechanical mixing is the physical blending of the soil and the barrier material underground. Excavation-insertion is the removal of a soil volume and adding barrier materials to the space created. Major vertical barrier emplacement technologies include trenching-backfilling; slurry trenching; and vertical drilling and injection, including boring (earth augering), cable tool drilling, rotary drilling, sonic drilling, jetting methods, injection-mixing in drilled holes, and deep soil mixing. Major horizontal barrier emplacement technologies include horizontal drilling, microtunneling, compaction boring, horizontal emplacement, longwall mining, hydraulic fracturing, and jetting methods

  20. Ballistic transport through graphene nanostructures of velocity and potential barriers

    International Nuclear Information System (INIS)

    Krstajic, P M; Vasilopoulos, P

    2011-01-01

    We investigate the electronic properties of graphene nanostructures when the Fermi velocity and the electrostatic potential vary in space. First, we consider the transmission T and conductance G through single and double barriers. We show that G for velocity barriers differs markedly from that for potential barriers for energies below the height of the latter and it exhibits periodic oscillations as a function of the energy for strong velocity modulation. Special attention is given to superlattices (SLs). It is shown that an applied bias can efficiently widen or shrink the allowed minibands of velocity-modulated SLs. The spectrum in the Kronig-Penney limit is periodic in the strength of the barriers. Collimation of an electron beam incident on an SL with velocity and potential barriers is present but it disappears when the potential barriers are absent. The number of additional Dirac points may change considerably if barriers and wells have sufficiently different Fermi velocities.

  1. Benefits of barrier fuel on fuel cycle economics

    International Nuclear Information System (INIS)

    Crowther, R.L.; Kunz, C.L.

    1988-01-01

    Barrier fuel rod cladding was developed to eliminate fuel rod failures from pellet/cladding stress/corrosion interaction and to eliminate the associated need to restrict the rate at which fuel rod power can be increased. The performance of barrier cladding has been demonstrated through extensive testing and through production application to many boiling water reactors (BWRs). Power reactor data have shown that barrier fuel rod cladding has a significant beneficial effect on plant capacity factor and plant operating costs and significantly increases fuel reliability. Independent of the fuel reliability benefit, it is less obvious that barrier fuel has a beneficial effect of fuel cycle costs, since barrier cladding is more costly to fabricate. Evaluations, measurements, and development activities, however, have shown that the fuel cycle cost benefits of barrier fuel are large. This paper is a summary of development activities that have shown that application of barrier fuel significantly reduces BWR fuel cycle costs

  2. On the evolution of a holocene barrier coast

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel

    in a distinct stratal stacking pattern of each of the investigated coastal barrier systems. We conclude that the overall infilling of the barrier systems over the Holocene was mainly controlled by sea-level rise and sediment supply. However, major storms and tidal channel migration have greatly affected......This thesis investigates the sedimentary evolution of a Holocene barrier coast with special focus on how barrier system stratigraphy is affected by changes in sea-level and sediment supply. Coastal barrier systems comprise about 13% of the world’s coastlines and they are mportant components...... of the stratigraphic record of the Earth. Sea-level rise and sediment supply are the two most important factors controlling barrier system evolution. Detailed depositional reconstructions of a number of barrier systems from the Danish Wadden Sea area have been carried out in order to evaluate the sedimentary effects...

  3. The effects of temperature on Schottky diode barrier height and evidence of multiple barrier

    International Nuclear Information System (INIS)

    Rabah, K.V.O.

    1994-07-01

    Experimental study of Capacitance-Voltage-Temperature (C-V-T) plots, Current-Voltage-Temperature (I-V-T) characteristics have been undertaken in order to determine the height of the Schottky barrier. The results of the barrier height obtained by the above two methods were found to differ as well as vary with temperature change. In view of this discrepancy in barrier height values, two further experiments were performed: one on activation energy (I-T) plots and the other on pulsed (I-V-T) characteristics, and the results were found to show a similar trend. The Schottky diode studied was a 30CP040. (author). 23 refs, 9 figs, 3 tabs

  4. Physician variation in perceived barriers to personal health

    Directory of Open Access Journals (Sweden)

    Rubenfire M

    2012-01-01

    Full Text Available Adam RB Kosteva1, Brian M Salata1, Sangeetha Mahadevan Krishnan2, Michael Howe3, Alissa Weber3, Melvyn Rubenfire2,3, Elizabeth A Jackson2,31Michigan Cardiovascular Research and Reporting Program, 2Division of Cardiovascular Medicine, 3Department of Internal Medicine, University of Michigan Health System, Ann Arbor, MI, USAObjective: Physicians’ personal health habits are associated with their counseling habits regarding physical activity. We sought to examine physicians’ own barriers to a healthy lifestyle by level of training and gender.Methods: Physicians at a major teaching hospital were surveyed regarding their lifestyle habits and barriers to healthy habits. The frequency of reported barriers was examined by years in practice (trainees vs staff physicians and gender.Results: 183 total responses were received. Over 20% of respondents were overweight. Work schedule was cited as the greatest barrier to regular exercise in 70.5% of respondents. Trainees were more likely to cite time constraints or cost as a barrier to a healthy diet compared to staff physicians. Staff physicians were more likely to report the time to prepare healthy foods as a barrier. For both trainees and staff physicians, time was a barrier to regular exercise. For trainees work schedule was a barrier, while both work schedule and family commitments were top barriers cited by staff physicians. Women were more likely to report family commitments as a barrier than men. Respondents suggested healthier options in vending machines and the hospital cafeteria, healthy recipes, and time and/or facilities for exercise at work as options to help overcome these barriers.Conclusion: Work schedules and family commitments are frequently reported by providers as barriers to healthy lifestyle. Efforts to reduce such barriers may lead to improved health habits among providers.Keywords: diet, exercise, counseling, prevention, gender, barriers, health

  5. Coastal Barrier Resource Areas, Barrier Islands and Spits; s44gbb89; Barrier Beaches as defined by RI CRMC were barrier beaches as defined by RI CRMC were identified on quad maps and manually digitized from tablets, Published in 1989, 1:24000 (1in=2000ft) scale, Rhode Island and Providence Plantations.

    Data.gov (United States)

    NSGIC State | GIS Inventory — Coastal Barrier Resource Areas dataset current as of 1989. Barrier Islands and Spits; s44gbb89; Barrier Beaches as defined by RI CRMC were barrier beaches as defined...

  6. Sub-barrier fusion and near-barrier quasi-elastic scattering

    International Nuclear Information System (INIS)

    Kolata, J.J.; Tighe, R.J.

    1990-01-01

    Elastic scattering of 32 S on 58,64 Ni and fusion of 32 S+ 58,64 Ni and 34 S+ 64 Ni have been measured at energies near the Coulomb barrier. Our results differ in several important respects from previous measurements on these systems. Coupled-channels calculations which explicitly allow for inelastic excitation and single-nucleon transfer reproduce the main features of the new data. Near-barrier elastic scattering of 48 Ca on 40 Ca has also been measured. These data provide evidence for the effect of strong coupling to positive Q-value channels other than single-nucleon transfer. 18 refs., 3 figs

  7. Modelization and simulation of capillary barriers

    International Nuclear Information System (INIS)

    Lisbona Cortes, F.; Aguilar Villa, G.; Clavero Gracia, C.; Gracia Lozano, J.L.

    1998-01-01

    Among the different underground transport phenomena, that due to water flows is of great relevance. Water flows in infiltration and percolation processes are responsible of the transport of hazardous wastes towards phreatic layers. From the industrial and geological standpoints, there is a great interest in the design of natural devices to avoid the flows transporting polluting substances. This interest is increased when devices are used to isolate radioactive waste repositories, whose life is to be longer than several hundred years. The so-called natural devices are those based on the superimposition of material with different hydraulic properties. In particular, the flow retention in this kind stratified media, in unsaturated conditions, is basically due to the capillary barrier effect, resulting from placing a low conductivity material over another with a high hydraulic conductivity. Covers designed from the effect above have also to allow a drainage of the upper layer. The lower cost of these covers, with respect to other kinds of protection systems, and the stability in time of their components make them very attractive. However, a previous investigation to determine their effectivity is required. In this report we present the computer code BCSIM, useful for easy simulations of unsaturated flows in a capillary barrier configuration with drainage, and which is intended to serve as a tool for designing efficient covers. The model, the numerical algorithm and several implementation aspects are described. Results obtained in several simulations, confirming the effectivity of capillary barriers as a technique to build safety covers for hazardous waste repositories, are presented. (Author)

  8. Boosters and barriers for direct cardiac reprogramming.

    Science.gov (United States)

    Talkhabi, Mahmood; Zonooz, Elmira Rezaei; Baharvand, Hossein

    2017-06-01

    Heart disease is currently the most significant cause of morbidity and mortality worldwide, which accounts for approximately 33% of all deaths. Recently, a promising and alchemy-like strategy has been developed called direct cardiac reprogramming, which directly converts somatic cells such as fibroblasts to cardiac lineage cells such as cardiomyocytes (CMs), termed induced CMs or iCMs. The first in vitro cardiac reprogramming study, mediated by cardiac transcription factors (TFs)-Gata4, Tbx5 and Mef2C-, was not enough efficient to produce an adequate number of fully reprogrammed, functional iCMs. As a result, numerous combinations of cardiac TFs exist for direct cardiac reprogramming of mouse and human fibroblasts. However, the efficiency of direct cardiac reprogramming remains low. Recently, a number of cellular and molecular mechanisms have been identified to increase the efficiency of direct cardiac reprogramming and the quality of iCMs. For example, microgrooved substrate, cardiogenic growth factors [VEGF, FGF, BMP4 and Activin A], and an appropriate stoichiometry of TFs boost the direct cardiac reprogramming. On the other hand, serum, TGFβ signaling, activators of epithelial to mesenchymal transition, and some epigenetic factors (Bmi1 and Ezh2) are barriers for direct cardiac reprogramming. Manipulating these mechanisms by the application of boosters and removing barriers can increase the efficiency of direct cardiac reprogramming and possibly make iCMs reliable for cell-based therapy or other potential applications. In this review, we summarize the latest trends in cardiac TF- or miRNA-based direct cardiac reprogramming and comprehensively discuses all molecular and cellular boosters and barriers affecting direct cardiac reprogramming. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Permeation barrier for lightweight liquid hydrogen tanks

    Energy Technology Data Exchange (ETDEWEB)

    Schultheiss, D.

    2007-04-16

    For the future usage of hydrogen as an automotive fuel, its on-board storage is crucial. One approach is the storage of liquid hydrogen (LH2, 20 K) in double-walled, vacuum insulated tanks. The introduction of carbon fiber reinforced plastics (CFRP) as structural material enables a high potential of reducing the weight in comparison to the state-of-the-art stainless steel tanks. The generally high permeability of hydrogen through plastics, however, can lead to long-term degradation of the insulating vacuum. The derived objective of this dissertation was to find and apply an adequate permeation barrier (liner) on CFRP. The investigated liners were either foils adhered on CFRP specimens or coatings deposited on CFRP specimens. The coatings were produced by means of thermal spraying, metal plating or physical vapor deposition (PVD). The materials of the liners included Al, Au, Cu, Ni and Sn as well as stainless steel and diamond-like carbon. The produced liners were tested for their permeation behavior, thermal shock resistance and adherence to the CFRP substrate. Additionally, SEM micrographs were used to characterize and qualify the liners. The foils, although being a good permeation barrier, adhered weakly to the substrate. Furthermore, leak-free joining of foil segments is a challenge still to be solved. The metal plating liners exhibited the best properties. For instance, no permeation could be detected through a 50 {mu}m thick Cu coating within the accuracy of the measuring apparatus. This corresponds to a reduction of the permeation gas flow by more than factor 7400 compared to uncoated CFRP. In addition, the metal platings revealed a high adherence and thermal shock resistance. The coatings produced by means of thermal spraying and PVD did not show a sufficient permeation barrier effect. After having investigated the specimens, a 170 liter CFRP tank was fully coated with 50 {mu}m Cu by means of metal plating. (orig.)

  10. BREASTFEEDING AND SOCIAL, CULTURAL, GEOPOLITICAL EMBODIED BARRIERS

    Directory of Open Access Journals (Sweden)

    Miriam Castaldo

    2016-01-01

    Full Text Available This study in medical anthropology was conducted at the National Institute for Health, Migration and Poverty (INMP, in Rome, Italy, and was carried out in 2013-2014 as part of the project “Clinical and social evaluation of medical practices in the treatment of infectious diseases in paediatrics for children of vulnerable populations”. At the end of the project, it was possible to ensure diagnostic accuracy, the proper prescription of antibiotic therapy and improve family care of children affected by pharyngotonsillitis. In addition, it was possible to acquire knowledge of the health of children with respect for certain social determinants. The anthropological research targeted mother’s of children and adolescents from the age of 3 to the age of 17 immigrated to Rome from Africa: sub-Saharan and North; furthermore from Asia: Indian subcontinent, West Asia, Eurasia, Middle East, Arabian peninsula; South-East Europe; Centre and South America. In this article we’ll consider only mother’s of 39 children and adolescents from Latin America (Argentina, Brazil, Colombia, Ecuador, El Salvador, Honduras, Nicaragua, Paraguay, Peru, Dominican Republic, Uruguay and Venezuela. The study aimed at analysing the formation and the socio-cultural representation, which emerged from interviews of women regarding barriers to breastfeeding; the effects of breastfeeding on the psychological and physical health of infants; the social and domestic consequences, which affect women who did not stop breastfeeding when they feel they should have. In Italy, as in other destination countries for global migrations, barriers that prevent the access to the healthcare system must be removed, barriers that are accentuated by linguistic and cultural incomprehension, through adequate multidisciplinary healthcare settings such as the one we are presenting, composed of a medical doctor, an anthropologist and a cultural mediator.

  11. Barriers to wheelchair use in the winter.

    Science.gov (United States)

    Ripat, Jacquie D; Brown, Cara L; Ethans, Karen D

    2015-06-01

    To test the hypothesis that challenges to community participation posed by winter weather are greater for individuals who use scooters, manual and power wheelchairs (wheeled mobility devices [WMDs]) than for the general ambulatory population, and to determine what WMD users identify as the most salient environmental barriers to community participation during the winter. Cross-sectional survey organized around 5 environmental domains: technological, natural, physical, social/attitudinal, and policy. Urban community in Canada. Convenience sample of WMD users or their proxy (N=99). Not applicable. Not applicable. Forty-two percent identified reduced outing frequency in winter months, associated with increased age (χ(3)=6.4, P=.04), lack of access to family/friends for transportation (χ(2)=8.1, P=.04), and primary type of WMD used in the winter (scooter χ(2)=8.8, P=.003). Most reported tires/casters becoming stuck in the snow (95%) or slipping on the ice (91%), difficulty ascending inclines/ramps (92%), and cold hands while using controls or pushing rims (85%); fewer identified frozen wheelchair/scooter batteries, seat cushions/backrests, or electronics. Sidewalks/roads were reported to be problematic by 99%. Eighty percent reported needing additional help in the winter. Limited community access in winter led to a sense of loneliness/isolation, and fear/anxiety related to safety. Respondents identified policies that limited participation during winter. People who use WMDs decrease their community participation in cold weather because of multiple environmental barriers. Clinicians, researchers, and policymakers can take a multidimensional approach to mitigate these barriers in order to enhance community participation by WMD users in winter. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  12. Pharmacogenetics in Europe: barriers and opportunities.

    Science.gov (United States)

    Gurwitz, D; Zika, E; Hopkins, M M; Gaisser, S; Ibarreta, D

    2009-01-01

    This paper reviews the current situation in the field of pharmacogenetics/pharmacogenomics (PGx) in Europe. High expectations surrounding the clinical application of PGx remain largely unmet, as only a limited number of such applications have actually reached the market and clinical practice. Thus, the potential impact of PGx-based diagnostics on healthcare and its socio-economic implications are still unclear. With the aim of shedding some light on these uncertainties, the Institute for Prospective Technological Studies (IPTS) of the European Commission's Joint Research Centre (JRC) has conducted a review of the 'state of the art' and a further analysis on the use of pharmacogenetics diagnostics for preventing toxic drug reactions and improving drug efficacy in Europe. The paper presents highlights from the JRC-IPTS studies and discusses possibilities for improving translation of PGx research in Europe by comparing some experiences in the USA. We also illustrate the related barriers for the clinical uptake of PGx in Europe with specific case-studies. Most of the barriers identified extend beyond the European context. This reflects the global problems of scarcity of data demonstrating proven clinical validity or utility and favorable cost-effectiveness studies to support the clinical application of PGx diagnostic tests in the clinical setting. Another key barrier is the lack of incentives for the private sector to invest in the development and licensing of PGx diagnostic tests for improving the safety and efficacy of out-of-patent drugs. It therefore seems that one key aspect where policy can affect the clinical uptake of PGx is via sustaining large-scale industry-academia collaborations for developing and proving the utility of PGx diagnostics. Copyright 2009 S. Karger AG, Basel.

  13. Cellulose insulation as an air barrier

    Energy Technology Data Exchange (ETDEWEB)

    Manning, K.

    1989-10-01

    The objective of this study was to determine if a wet sprayed cellulose wall insulation system would function satisfactorily without use of a polyethylene air/vapour barrier. The research was designed to demonstrate that this particular insulation system would form enough of a barrier to air leakage, that moisture accumulation from condensation and vapour diffusion would be insignificant. Field work conducted in Alberta, involved construction of a conventional duplex housing unit which was insulated with wet sprayed cellulose in the exterior walls and dry loose-fill cellulose in the attic areas. One half of the unit did not have a polyethylene air/vapor barrier installed. Air leakage and exterior wall moisture levels were monitored for a year following construction. Data collected during this time indicated that the moisture added to the walls during the insulating process was dissipated over the study period. The presence of polyethylene sheeting had no significant effect on the moisture levels in either the wall or attic areas of the test structure. On the other hand, testing indicated that the use of polyethylene sheeting in the wall system did serve to improve blower door air test results. In conclusion, although the air leakage resistance apparently provided by the polyethylene sheeting is significant, the amount is probably not more than could otherwise be obtained by more careful attention to sealing procedures such as those used in the airtight drywall technique. A more important finding is that the use of polyethylene sheeting is not essential in a structure which has the degree of air leakage resistance provided by the insulation system used in this project. 6 figs., 2 tabs.

  14. Effect of breakup on near barrier fusion

    International Nuclear Information System (INIS)

    Dasgupta, M.; Berriman, A.C.; Butt, R.D.; Hinde, D.J.; Morton, C.R.; Newton, J.O.

    2000-01-01

    Full text: Unstable neutron-rich nuclei having very weakly bound neutrons exhibit characteristic features such as a neutron halo extending to large radii, and a low energy threshold for breakup. These features may dramatically affect fusion and other reaction processes. It is well accepted that the extended nuclear matter distribution will lead to an enhancement in fusion cross-sections over those for tightly bound nuclei. The effect of couplings to channels which act as doorways to breakup is, however, controversial, with model predictions differing in the relative magnitudes of enhancement and suppression. To investigate the effect on fusion of couplings specific to unstable neutron-rich nuclei, it is necessary to understand (and then predict) the cross-sections expected for their stable counterparts. This requires knowledge of the energy of the average fusion barrier, and information on the couplings. Experimentally all this information can be obtained from precisely measured fusion cross-sections. Such precision measurements of complete fusion cross-sections for 9 Be + 208 Pb and 6 Li, 7 Li + 209 Bi systems have been done at the Australian National University. The distribution of fusion barriers extracted from these data were used to reliably predict the expected fusion cross-sections. Comparison of the theoretical expectations with the experimentally measured cross-sections show conclusively that complete fusion, at above barrier energies, for all three systems is suppressed (by about 30%) compared with the fusion of more tightly bound nuclei. These measurements, in conjunction with incomplete fusion cross-sections, which were also measured, should encourage a complete theoretical description of fusion and breakup

  15. Simulating barrier penetration during combat. Technical report

    International Nuclear Information System (INIS)

    De Laquil, P. III.

    1980-04-01

    A computer program, BARS, simulates combat between an adversary group attempting to hijack special nuclear material and escort personnel attempting to protect it. BARS is designed to investigate how various combat strategies and levels of performance affect the time required to penetrate barriers (armor, deterrent systems, etc.) against forcible entry. A Monte Carlo code, BARS uses a game theoretic approach to allocate the attacking and defending forces. Combat suppression is simulated using a stochastic state-transition model for the behavior of individuals under combat stress. The BARS program was developed as part of the overall combat modelling effort of the transportation safeguards program

  16. Formation and collapse of internal transport barrier

    International Nuclear Information System (INIS)

    Fukuyama, A.; Itoh, K.; Itoh, S.I.; Yagi, M.

    1999-01-01

    A theoretical model of internal transport barrier (ITB) is developed. The transport model based on the self-sustained turbulence theory of the current-diffusive ballooning mode is extended to include the effects of ExB rotation shear. Delayed formation of ITB is observed in transport simulations. The influence of finite gyroradius is also discussed. Simulation of the current ramp-up experiment successfully described the radial profile of density, temperature and safety factor. A model of ITB collapse due to magnetic braiding is proposed. Sudden enhancement of transport triggered by overlapping of magnetic islands terminates ITB. The possibility of destabilizing global low-n modes is also discussed. (author)

  17. High speed PVD thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Beele, W. [Sulzer Metco Coatings BV (Netherlands); Eschendorff, G. [Sulzer Metco Coatings BV (Netherlands); Eldim BV (Netherlands)

    2006-07-15

    The high speed PVD process (HS-PVD) combines gas phase coating synthesis with high deposition rates. The process has been demonstrated for high purity YSZ deposited as a chemically bonded top thermal barrier with columnar structure of EB-PVD features. The process can manufacture EB-PVD like coatings that match in regards to their TGO-formation and columnar structure. Coatings with a columnar structure formed by individual columns of 1/4 of the diameter of a classical EB-PVD type TBC have been deposited. These coatings have the potential to prove a significant reduction in thermal conductivity and in erosion performance. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  18. Ceramides and barrier function in healthy skin

    DEFF Research Database (Denmark)

    Jungerstedt, J; Hellgren, Lars; Drachmann, Tue

    2010-01-01

    Lipids in the stratum corneum are key components in the barrier function of the skin. Changes in lipid composition related to eczematous diseases are well known, but limited data are available on variations within healthy skin. The objective of the present study was to compare ceramide subgroups...... and ceramide/cholesterol ratios in young, old, male and female healthy skin. A total of 55 participants with healthy skin was included in the study. Lipid profiles were correlated with transepidermal water loss and with information on dry skin from a questionnaire including 16 people. No statistically...

  19. On the Existence of Compositional Barrier Certificates

    DEFF Research Database (Denmark)

    Sloth, Christoffer; Wisniewski, Rafael; Pappas, George J.

    2012-01-01

    This paper provides a necessary and sufficient condition for the compositional verification of a continuous system with additively separable barrier functions. The compositional safety verification enables the verification of an interconnection of subsystems. The idea behind the compositional...... of a system that cannot be verified using the compositional method, but can be verified using a centralized method. This example highlights how not to decompose systems, and should be used to guide the decomposition of a system into appropriate subsystems. Finally, we provide a second condition...

  20. DNA nanovehicles and the biological barriers

    DEFF Research Database (Denmark)

    Okholm, Anders Hauge; Kjems, Jørgen

    2016-01-01

    DNA is emerging as a smart material to construct nanovehicles for targeted drug delivery. The programmability of Watson-Crick base paring enables construction of defined and dynamic DNA nanostructures of almost arbitrary shape and DNA can readily be functionalized with a variety of molecular...... be overcome. Here, we highlight recent strategies for DNA nanostructures in drug delivery, DNA nanovehicles, to facilitate targeting and crossing of the biological barriers. In light of this, we discuss future solutions and challenges for DNA nanovehicles to unravel their great potential to facilitate...

  1. Reliability modeling of an engineered barrier system

    International Nuclear Information System (INIS)

    Ananda, M.M.A.; Singh, A.K.; Flueck, J.A.

    1993-01-01

    The Weibull distribution is widely used in reliability literature as a distribution of time to failure, as it allows for both increasing failure rate (IFR) and decreasing failure rate (DFR) models. It has also been used to develop models for an engineered barrier system (EBS), which is known to be one of the key components in a deep geological repository for high level radioactive waste (HLW). The EBS failure time can more realistically be modelled by an IFR distribution, since the failure rate for the EBS is not expected to decrease with time. In this paper, we use an IFR distribution to develop a reliability model for the EBS

  2. Opportunities and barriers to straw construction

    DEFF Research Database (Denmark)

    White, Caroline Meyer; Howard, Thomas J.; Lenau, Torben Anker

    2012-01-01

    produced to support communication between clients and the consultants and facilitate the straw build design and decision making process. The intended audiences for the design guide are clients of small scale construction projects, architects, engineers, builders of straw construction, homeowner...... construction, and a series of qualitative interviews with a variety of stakeholders from previous straw build housing projects, results were gathered to find the most influential motives, barriers and considerations for straw build housing construction. Based on this empirical data, a design guide has been...

  3. Reliability modeling of an engineered barrier system

    International Nuclear Information System (INIS)

    Ananda, M.M.A.; Singh, A.K.; Flueck, J.A.

    1993-01-01

    The Weibull distribution is widely used in reliability literature as a distribution of time to failure, as it allows for both increasing failure rate (IFR) and decreasing failure rate (DFR) models. It has also been used to develop models for an engineered barrier system (EBS), which is known to be one of the key components in a deep geological repository for high level radioactive waste (HLW). The EBS failure time can more realistically be modelled by an IFR distribution, since the failure rate for the EBS is not expected to decrease with time. In this paper, an IFR distribution is used to develop a reliability model for the EBS

  4. Dielectric barrier discharge processing of aerospace materials

    International Nuclear Information System (INIS)

    Scott, S J; Figgures, C C; Dixon, D G

    2004-01-01

    We report the use of atmospheric pressure, air based, dielectric barrier discharges (DBD) to treat materials commonly used in the aerospace industries. The material samples were processed using a test-bed of a conventional DBD configuration in which the sample formed one of the electrodes and was placed in close proximity to a ceramic electrode. The discharges generated a powerful, cold oxidizing environment which was able to remove organic contaminants, etch primer and paint layers, oxidize aluminium and roughen carbon fibre composites by the selective removal of resin

  5. Formation and collapse of internal transport barrier

    International Nuclear Information System (INIS)

    Fukuyama, A.; Itoh, K.; Itoh, S.-I.; Yagi, M.

    2001-01-01

    A theoretical model of internal transport barrier (ITB) is developed. The transport model based on the self-sustained turbulence theory of the current-diffusive ballooning mode is extended to include the effects of ExB rotation shear. Delayed formation of ITB is observed in transport simulations. The influence of finite gyroradius is also discussed. Simulation of the current ramp-up experiment successfully described the radial profile of density, temperature and safety factor. A model of ITB collapse due to magnetic braiding is proposed. Sudden enhancement of transport triggered by overlaping of magnetic islands terminates ITB. The possibility of destabilizing global low-n modes is also discussed. (author)

  6. High speed PVD thermal barrier coatings

    International Nuclear Information System (INIS)

    Beele, W.; Eschendorff, G.

    2006-01-01

    The high speed PVD process (HS-PVD) combines gas phase coating synthesis with high deposition rates. The process has been demonstrated for high purity YSZ deposited as a chemically bonded top thermal barrier with columnar structure of EB-PVD features. The process can manufacture EB-PVD like coatings that match in regards to their TGO-formation and columnar structure. Coatings with a columnar structure formed by individual columns of 1/4 of the diameter of a classical EB-PVD type TBC have been deposited. These coatings have the potential to prove a significant reduction in thermal conductivity and in erosion performance. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  7. Reactive barriers for 137Cs retention

    International Nuclear Information System (INIS)

    Krumhansl, James L.; Brady, Patrick V.; Anderson, Howard L.

    2000-01-01

    137 Cs was dispersed globally by cold war activities and, more recently, by the Chernobyl accident. Engineered extraction of 137 Cs from soils and groundwaters is exceedingly difficult. Because the half life of 137 Cs is only 30.2 years, remediation might be more effective (and less costly) if 137 Cs bioavailability could be demonstrably limited for even a few decades by use of a reactive barrier. Essentially permanent isolation must be demonstrated in those few settings where high nuclear level wastes contaminated the environment with 135 Cs (half life 2.3x10 6 years) in addition to 137 Cs. Clays are potentially a low-cost barrier to Cs movement, though their long-term effectiveness remains untested. To identify optimal clays for Cs retention Cs resorption was measured for five common clays: Wyoming Montmorillonite (SWy-1), Georgia Kaolinites (KGa-1 and KGa-2), Fithian Illite (F-Ill), and K-Metabentonite (K-Mbt). Exchange sites were pre-saturated with 0.16 M CsCl for 14 days and readily exchangeable Cs was removed by a series of LiNO 3 and LiCl washes. Washed clay were then placed into dialysis bags and the Cs release to the deionized water outside the bags measured. Release rates from 75 to 139 days for SWy-1, K-Mbt and F- 111 were similar; 0.017 to 0.021% sorbed Cs released per day. Both kaolinites released Cs more rapidly (0.12 to 0.05% of the sorbed Cs per day). In a second set of experiments, clays were doped for 110 days and subjected to an extreme and prolonged rinsing process. All the clays exhibited some capacity for irreversible Cs uptake so most soils have some limited ability to act as a natural barrier to Cs migration. However, the residual loading was greatest on K-Mbt (∼ 0.33 wt% Cs). Thus, this clay would be the optimal material for constructing artificial reactive barriers

  8. Barrier inhomogeneities limited current and 1/f noise transport in GaN based nanoscale Schottky barrier diodes

    Science.gov (United States)

    Kumar, Ashutosh; Heilmann, M.; Latzel, Michael; Kapoor, Raman; Sharma, Intu; Göbelt, M.; Christiansen, Silke H.; Kumar, Vikram; Singh, Rajendra

    2016-01-01

    The electrical behaviour of Schottky barrier diodes realized on vertically standing individual GaN nanorods and array of nanorods is investigated. The Schottky diodes on individual nanorod show highest barrier height in comparison with large area diodes on nanorods array and epitaxial film which is in contrast with previously published work. The discrepancy between the electrical behaviour of nanoscale Schottky diodes and large area diodes is explained using cathodoluminescence measurements, surface potential analysis using Kelvin probe force microscopy and 1ow frequency noise measurements. The noise measurements on large area diodes on nanorods array and epitaxial film suggest the presence of barrier inhomogeneities at the metal/semiconductor interface which deviate the noise spectra from Lorentzian to 1/f type. These barrier inhomogeneities in large area diodes resulted in reduced barrier height whereas due to the limited role of barrier inhomogeneities in individual nanorod based Schottky diode, a higher barrier height is obtained. PMID:27282258

  9. Barriers to treatment for older adults seeking psychological therapy.

    Science.gov (United States)

    Wuthrich, Viviana M; Frei, Jacqueline

    2015-07-01

    Older adults with mental health disorders underutilize mental health services more than other adults. While there are well known general barriers to help seeking across the population, specific barriers for older adults include difficulties with transportation, beliefs that it is normal to be anxious and depressed in old age, and beliefs by referrers that psychological therapy is less likely to be effective. This study examined barriers related to identifying the need for help, seeking help and participating in therapy in a clinical population of older adults. Sixty older adults (aged 60-79 years) with comorbid anxiety and unipolar mood disorders completed barriers to treatment questionnaires before and after psychological group treatment, as well as measures of cognitive ability, anxiety, depression, and quality of life at baseline. The greatest barriers to help seeking related to difficulties identifying the need for help, with 50% of the sample reporting their belief that their symptoms were normal as a major barrier. Other major barriers identified were related to: self-reliance, cost of treatment, and fear of medication replicating previous findings. The main barriers reported for difficulties in continuing therapy included not finding therapy helpful, cost of treatment, and thinking that the therapist did not understand their issues. The main barriers identified related to issues with identifying the need to seek help. More attention is needed to educate older adults and professionals about the need for, and effectiveness of, psychological therapies for older adults with anxiety and depression to reduce this barrier to help seeking.

  10. [Prevalence of barriers for physical activity in adolescents].

    Science.gov (United States)

    Santos, Mariana Silva; Hino, Adriano Akira Ferreira; Reis, Rodrigo Siqueira; Rodriguez-Añez, Ciro Romélio

    2010-03-01

    The aim of this study was to analyze the prevalence and association of barriers to physical activity among adolescents. This cross-sectional study evaluated a representative sample of public high school students in Curitiba-PR, Brazil. A total of 1,609 school adolescents (59.7% male) between 14 and 18 years of age answered a questionnaire on physical activity status and barriers to physical activity. Logistic regressions were conducted for each barrier investigated to verify the association between the prevalence of barriers and physical activity, adjusting for confounding variables (age and socioeconomic status). Analyses were done separately for boys and girls. Only 22% of boys and 9% of girls achieved the current physical activity recommendation. Among the 12 barriers investigated, only "there is nobody to take" did not differ between boys and girls. The perception of barriers was higher for girls than boys (p barriers. "Lack of friends company" and "feel lazy" were the barriers most often reported by boys (30.4%) and girls (51.8%) respectively; however, the barrier most strongly associated with prevalence of physical inactivity was "prefer to do other things" for both boys (OR = 5.02 (2.69 - 9.37); p barriers for the practice of physical activity were more prevalent in girls and differed as to the extent of importance between genders.

  11. Empirical investigation of energy efficiency barriers in Italian manufacturing SMEs

    International Nuclear Information System (INIS)

    Trianni, Andrea; Cagno, Enrico; Worrell, Ernst; Pugliese, Giacomo

    2013-01-01

    The paper identifies and evaluates barriers to industrial energy efficiency through the investigation of 48 manufacturing Small and Medium-sized Enterprises (SMEs) in Northern Italy. The research provides interesting suggestions both for enterprises and energy policy-makers. Firstly, economic and information barriers are perceived as the major obstacles to the adoption of energy-efficient technologies, whilst behavioural barriers do not seem to affect enterprises very much. Nonetheless, despite what declared, the most relevant barriers are the lack of interest in energy efficiency and the existence of other priorities, thus showing that decision-makers tend to downgrade energy efficiency to a marginal issue. Furthermore, perceived barriers do not take place exclusively in implementing energy-efficient technologies, but, with comparable importance, also in generating the interest and knowledge of the opportunities. Moreover, the study highlights that relevant differences can be appreciated for both perceived and real barriers even among SMEs, that thus should not be bundled together. In addition to that, other factors affect barriers, stimulating future research: indeed, lower real barriers can be observed with higher complexity of the production, high variability of the demand and strong competitors. -- Highlights: ► Evidence of existing misalignments between perceived and real barriers to the adoption of energy-efficient technologies. ► Relevance of barriers to the generation of interest towards energy efficiency. ► Evidence of firm's size (within SMEs) and energy expenditures on barriers to energy efficiency. ► Importance, for energy efficiency barriers, of avoid bundling SMEs as a whole. ► Preliminary evidence of factors related to supply chain complexity affecting barriers to energy efficiency.

  12. THE TOURISM BARRIERS OF THE DISABLED

    Directory of Open Access Journals (Sweden)

    Nagy Andreea

    2011-07-01

    Full Text Available This article seeks to address a very sensitive issue in Romania, the disabled tourism. The natural question is whether tourism can respond and meet the needs of such people. Internationally, the researches in detail about tourism for people with disabilities are limited in this direction, and those who exist are focused more on lack of physical access to certain services in the hotel units.-As for the problems (barriers that a person with disabilities may face when seeking to participate in the act of travel there were found numerous internal and external barriers in trying to participate in tourism activities-The study seeks to identify how normal people behave towards people with disabilities and aims to demonstrate the existence of correlations between the responses of the interviewees, which would lead to the presentation as close to the truth as possible of the results from the sample (section, transposed over the population from which the sample belongs and also lead to finding conclusions on which there could be made several proposals.

  13. Enablers of and barriers to abortion training.

    Science.gov (United States)

    Guiahi, Maryam; Lim, Sahnah; Westover, Corey; Gold, Marji; Westhoff, Carolyn L

    2013-06-01

    Since the legalization of abortion services in the United States, provision of abortions has remained a controversial issue of high political interest. Routine abortion training is not offered at all obstetrics and gynecology (Ob-Gyn) training programs, despite a specific training requirement by the Accreditation Council for Graduate Medical Education. Previous studies that described Ob-Gyn programs with routine abortion training either examined associations by using national surveys of program directors or described the experience of a single program. We set out to identify enablers of and barriers to Ob-Gyn abortion training in the context of a New York City political initiative, in order to better understand how to improve abortion training at other sites. We conducted in-depth qualitative interviews with 22 stakeholders from 7 New York City public hospitals and focus group interviews with 62 current residents at 6 sites. Enablers of abortion training included program location, high-capacity services, faculty commitment to abortion training, external programmatic support, and resident interest. Barriers to abortion training included lack of leadership continuity, leadership conflict, lack of second-trimester abortion services, difficulty obtaining mifepristone, optional rather than routine training, and antiabortion values of hospital personnel. Supportive leadership, faculty commitment, and external programmatic support appear to be key elements for establishing routine abortion training at Ob-Gyn residency training programs.

  14. Testing of isolation barrier sealing surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Graves, C.E.

    1994-12-15

    Isolation barrier doors are to be installed in the 105KE and 105KW basins as part of the 1994 unreviewed safety question (USQ) resolution plan to isolate the fuel storage basin from the fuel discharge chute. Included in this installation is the placement of new sealing surfaces for the barriers by affixing stainless steel plates to existing carbon steel angle bars with a specially formulated epoxy adhesive/sealant material. The sealant is a two-part component consisting of an epoxy resin (the condensation product of bisphenol A and epichlorohydrin) and a curing agent (a proprietary cycloaliphatic polyamine). The sealant is solvent free (complying with air pollution regulations) and capable of withstanding the surrounding radiation fields over an estimated 15-year service life. The epoxy sealant experiences negligible water damage partly because of its hydrophobic (water-repelling) nature. With bond tensile strengths measured at greater than 862 kPa (125 lbf/in{sup 2}), the epoxy sealant is judged acceptable for its intended application. The four-hour pot life of the epoxy sealant provides sufficient time to apply the epoxy, examine the epoxy bead for continuity, and position the stainless steel sealing plates.

  15. Rare disease research: Breaking the privacy barrier

    Directory of Open Access Journals (Sweden)

    Deborah Mascalzoni

    2014-06-01

    Full Text Available Due to the few patients affected, rare disease research has to count on international registries to exist in order to produce significant research outputs. Data sharing of registries is therefore a unique resource to allow rare disease research to flourish and any lost data will jeopardize the quality of an already extremely difficult research. The rules usually applied to research such as the right to withdraw or the need for specific consent for every use of data can be detrimental in order to get effective results. Privacy rights regulated through traditional informed consent mechanisms have been regarded as a major barrier in order to effectively share data worldwide. Some authors argue that this barrier hampers results that could be beneficial to the patients so that another right will be overstated: the right to quality healthcare. We argue in this paper that privacy has been often interpreted just one-sided as the right to secrecy but it can entail another meaning: the right to manage one's own private sphere. Managing it pertains, not only to the right to deny access, but also to the right to grant access. At the same time research on patient participation and transparency shows that new forms of IT-based informed consent can provide a good balance between the right of individuals to be in control of their data and the opportunity for science to pursue international research.

  16. Corrosion of barrier materials in seawater environments

    International Nuclear Information System (INIS)

    Heiser, J.H.; Soo, P.

    1995-07-01

    A brief review has been carried out on the performance of barrier materials for low-level radioactive wastes in seawater environments. The environments include those for shallower coastal waters as well as the deep ocean (down to 3800 m). The review is mainly focused on metallic materials since they are the most common for seawater service and they have the largest data base. Information from the literature is usually pertinent to shallower coastal locations, but there is a valuable source of corrosion data obtained from several studies of metallic specimens exposed to ocean-bed conditions. In addition, the corrosion of carbon steel barriers has been evaluated for actual waste containers that were retrieved from previously-used disposal sites in the Atlantic and Pacific Oceans. Of the metallic materials studied, carbon steel showed the least corrosion resistance. Failure by non-uniform attack in a typical waste container could occur in as little as 25 y in some ocean environments ' Penetration by local attack, such as pitting and crevice corrosion resistance was also observed for more expensive materials such as low-alloy steels, stainless steels, titanium alloys, zirconium alloys, copper alloys, nickel alloys, aluminum alloys, and lead alloys

  17. Barriers of six sigma in healthcare organizations

    Directory of Open Access Journals (Sweden)

    Serkan Deniz

    2018-09-01

    Full Text Available Six Sigma approach is based on decreasing defects and variations in the products and processes, and it provides important benefits to healthcare organizations. This study aims to identify managers’ opinions, who work in private healthcare organizations, about the reasons behind not using Six Sigma in their organizations. The research was performed between December 2016 and March 2018 in private healthcare organizations (private hospitals and medical centers operating in Turkey and not using Six Sigma approach. Data were collected from managers, who have knowledge about Six Sigma, through using surveys. In this study, survey methodology was used to collect data. According to the results, the biggest barrier related to not using Six Sigma is based on the lack of knowledge about Six Sigma. The other important barrier about the diffusion of Six Sigma within this organizations is related to the lack of support from top management and leaders. Another finding about the reasons of not applying Six Sigma approach is that there is not a statistically significant difference among managers in terms of their managerial position. In order to overcome the lack of knowledge about Six Sigma, it is advised that managers should take steps in the direction of promoting Six Sigma within their current organization, and provide necessary support and leadership about the process.

  18. Nurses' Psychosocial Barriers to Suicide Risk Management

    Directory of Open Access Journals (Sweden)

    Sharon Valente

    2011-01-01

    Full Text Available Suicide remains a serious health care problem and a sentinel event tracked by The Joint Commission. Nurses are pivotal in evaluating risk and preventing suicide. Analysis of nurses' barriers to risk management may lead to interventions to improve management of suicidal patients. These data emerged from a random survey of 454 oncology nurses' attitudes, knowledge of suicide, and justifications for euthanasia. Instruments included a vignette of a suicidal patient and a suicide attitude questionnaire. Results. Psychological factors (emotions, unresolved grief, communication, and negative judgments about suicide complicate the nurse's assessment and treatment of suicidal patients. Some nurses (=122 indicated that euthanasia was never justified and 11 were unsure of justifications and evaluated each case on its merits. Justifications for euthanasia included poor symptom control, poor quality of life, incurable illness or permanent disability, terminal illness, and terminal illness with inadequate symptom control or impending death, patient autonomy, and clinical organ death. The nurses indicated some confusion and misconceptions about definitions and examples of euthanasia, assisted suicide, and double effect. Strategies for interdisciplinary clinical intervention are suggested to identify and resolve these psychosocial barriers.

  19. Investigation of a natural geochemical barrier

    International Nuclear Information System (INIS)

    1991-02-01

    Groundwater data from lysimeters and monitor wells in the vicinity of the Bowman, North Dakota, Uranium Mill Tailings Remedial Action (UMTRA) Project site indicated that there is a mechanism in the subsurface which cleans up downward-percolating fluids. It was hypothesized that clays and organic materials in the sediments sequestered hazardous constituents from infiltrating fluids. A program was designed to collect sediment cores from various locations on and around the site and to analyze the sediments to determine whether there has been a build up of hazardous constituents in any specific type of sedimentary material. Materials that concentrate the hazardous constituents would be potential candidates to be used in constructed geochemical barriers. The water quality of the groundwater contained within the sedimentary section indicates that there is a transport of contaminants down through the sediments and that these contaminants are removed from solution by the iron-bearing minerals in the organic-rich lignite beds. The data gathered during the course of this investigation indicate that the lignite ashing operations have added very little of the hazardous constituents of concern--arsenic, chromium, molybdenum, selenium, or uranium--to the sediments beneath the UMTRA Project site. At both locations, the hazardous constituents are concentrated in the upper most lignite bed. These data offer a natural analog for laboratory tests in which sphagnum peat was used to sequester hazardous constituents. Constructed geochemical barriers are a viable mechanism for the clean-up of the majority of hazardous constituents from uranium mill tailings in groundwater

  20. Neutrophils Compromise Retinal Pigment Epithelial Barrier Integrity

    Directory of Open Access Journals (Sweden)

    Jiehao Zhou

    2010-01-01

    Full Text Available We hypothesized that neutrophils and their secreted factors mediate breakdown of the integrity of the outer blood-retina-barrier by degrading the apical tight junctions of the retinal pigment epithelium (RPE. The effect of activated neutrophils or neutrophil cell lysate on apparent permeability of bovine RPE-Choroid explants was evaluated by measuring [H] mannitol flux in a modified Ussing chamber. The expression of matrix metalloproteinase- (MMP- 9 in murine peritoneal neutrophils, and the effects of neutrophils on RPE tight-junction protein expression were assessed by confocal microscopy and western blot. Our results revealed that basolateral incubation of explants with neutrophils decreased occludin and ZO-1 expression at 1 and 3 hours and increased the permeability of bovine RPE-Choroid explants by >3-fold (P<.05. Similarly, basolateral incubation of explants with neutrophil lysate decreased ZO-1 expression at 1 and 3 hours (P<.05 and increased permeability of explants by 75%. Further, we found that neutrophils prominently express MMP-9 and that incubation of explants with neutrophils in the presence of anti-MMP-9 antibody inhibited the increase in permeability. These data suggest that neutrophil-derived MMP-9 may play an important role in disrupting the integrity of the outer blood-retina barrier.

  1. Active commuting: prevalence, barriers, and associated variables.

    Science.gov (United States)

    Silva, Kelly Samara; Vasques, Daniel Giordani; Martins, Caroline de Oliveira; Williams, Laura Ashley; Lopes, Adair S

    2011-08-01

    Research has demonstrated that adolescents who actively commute have higher levels of physical activity (PA), which have declined precipitously over the past 30 years. The purpose of this study was to describe the prevalence of active commuting to school; and to identify barriers associated with active commuting. A cross-sectional study was conducted with 1672 students (46.8% boys and 53.2% girls) from 11 to 17 years of age in Caxias do Sul/RS, Brazil. The students were asked to answer questionnaires about active transport, PA, and sedentary behaviors. They also completed a cardiovascular fitness test and body composition measurements. The study used a multivariate Poisson regression analysis. A total of 62.5% of students were observed to actively commute and the prevalence ratio (PR) of not actively commuting was associated with the type of school (Private: 2.41; 1.47, 3.95) and the time spent on commuting (>20 min: 1.93; 1.23, 3.03). The associated barriers to passive commuting were distance (3.02; 1.95, 4.71), crime/danger (2.65; 1.82, 3.85), and traffic (1.75; 1.19, 2.58). This study showed that environmental variables were strongly associated with active commuting. However, no alterations in body composition or other behavioral variables were observed after adjustment.

  2. Testing of isolation barrier sealing surfaces

    International Nuclear Information System (INIS)

    Graves, C.E.

    1994-01-01

    Isolation barrier doors are to be installed in the 105KE and 105KW basins as part of the 1994 unreviewed safety question (USQ) resolution plan to isolate the fuel storage basin from the fuel discharge chute. Included in this installation is the placement of new sealing surfaces for the barriers by affixing stainless steel plates to existing carbon steel angle bars with a specially formulated epoxy adhesive/sealant material. The sealant is a two-part component consisting of an epoxy resin (the condensation product of bisphenol A and epichlorohydrin) and a curing agent (a proprietary cycloaliphatic polyamine). The sealant is solvent free (complying with air pollution regulations) and capable of withstanding the surrounding radiation fields over an estimated 15-year service life. The epoxy sealant experiences negligible water damage partly because of its hydrophobic (water-repelling) nature. With bond tensile strengths measured at greater than 862 kPa (125 lbf/in 2 ), the epoxy sealant is judged acceptable for its intended application. The four-hour pot life of the epoxy sealant provides sufficient time to apply the epoxy, examine the epoxy bead for continuity, and position the stainless steel sealing plates

  3. Barriers affecting adherence to radiation treatment and strategies to overcome those barriers.

    Science.gov (United States)

    Rangarajan, R; Jayaraman, K

    2017-01-01

    The WHO defines adherence as the extent to which a patient's behavior coincides with recommendations from a health-care provider. Nonadherence to cancer treatment has a major impact on the therapeutic outcome. To assess the prevalence of nonadherence to radiation regimen and to analyze the factors that affect adherence to cancer treatment. Patients receiving radiation treatment in our hospital were screened for adherence to appointment keeping and to the prescribed radiation regimen and patients who had unplanned treatment breaks during treatment were interviewed. Between January and July 2013, we identified 61 patients who had unplanned breaks during treatment. We analyzed the social, emotional, educational, economic, and therapeutic barriers that led to nonadherence. Of the 61 patients who had unplanned breaks during treatment, 54% were males and 46% were females. Fifty-seven percent of patients had head and neck cancers and 25% had gynecological cancers. Seventy-one percent of patients were planned for concurrent chemoradiation. The number of days of unplanned treatment breaks ranged from 3 to 27 days. Social and therapeutic barriers were found to be the most common factor that led to nonadherence in these patients. Identification of barriers that lead to nonadherence, designing strategies to overcome such barriers and effective communication becomes imperative to ensure uninterrupted treatment. Based on the above analysis, we have designed several strategies to improve adherence to treatment among our patients.

  4. Current-voltage relation for thin tunnel barriers: Parabolic barrier model

    DEFF Research Database (Denmark)

    Hansen, Kim; Brandbyge, Mads

    2004-01-01

    We derive a simple analytic result for the current-voltage curve for tunneling of electrons through a thin uniform insulating layer modeled by a parabolic barrier. Our model, which goes beyond the Wentzel–Kramers–Brillouin approximation, is applicable also in the limit of highly transparant...

  5. HRE-Pond Cryogenic Barrier Technology Demonstration: Pre- and Post-Barrier Hydrologic Assessment

    International Nuclear Information System (INIS)

    Moline, G.R.

    1999-01-01

    The Homogeneous Reactor Experiment (HRE) Pond is the site of a former impoundment for radioactive wastes on the Oak Ridge Reservation (ORR) in east Tennessee. The pond received radioactive wastes from 1957 to 1962, and was subsequently drained, filled with soil, and covered with an asphalt cap. The site is bordered to the east and south by an unnamed stream that contains significant concentrations of radioactive contaminants, primarily 90 Sr. Because of the proximity of the stream to the HRE disposal site and the probable flow of groundwater from the site to the stream, it was hypothesized that the HRE Pond has been a source of contamination to the creek. The HRE-Pond was chosen as the site of a cryogenic barrier demonstration to evaluate this technology as a means for rapid, temporary isolation of contaminants in the type of subsurface environment that exists on the ORR. The cryogenic barrier is created by the circulation of liquid CO 2 through a system of thermoprobes installed in boreholes which are backfilled with sand. The probes cool the subsurface, creating a vertical ice wall by freezing adjacent groundwater, effectively surrounding the pond on four sides. The purpose of this investigation was to evaluate the hydrologic conditions within and around the pond prior to, during, and after the cryogenic barrier emplacement. The objectives were (1) to provide a hydrologic baseline for post-banner performance assessment, (2) to confirm that the pond is hydraulically connected to the surrounding sediments, (3) to determine the likely contaminant exit pathways from the pond, and (4) to measure changes in hydrologic conditions after barrier emplacement in order to assess the barrier performance. Because relatively little information about the subsurface hydrology and the actual configuration of the pond existed, data from multiple sources was required to reconstruct this complex system

  6. SOME OBSERVATIONS ON THE DESIGN OF NOISE BARRIERS

    Directory of Open Access Journals (Sweden)

    Arkadiusz BOCZKOWSKI

    2013-04-01

    Full Text Available The issue connected with effectiveness of noise barriers has been the subject of numerous considerations among acousticians. On the one hand, noise barriers are still the most popular and the most frequently used protection against traffic noise, on the other hand, however, the excessive number of noise barriers and the results of research focusing on effectiveness of the existing barriers make us reflect whether it is reasonable to use them. Very often low effectiveness of noise barriers is related to a badly conducted designing process. This article presents the basic mistakes made by noise barriers’ designers and the consequences thereof. Next, the paper describes the appropriate approach to the process of the noise barriers’ design which consists in the use of computer methods and conducting of a detailed analysis of the acoustic field’s distribution both behind the barrier and on the facades of the acoustically protected buildings.

  7. Urban sound energy reduction by means of sound barriers

    Directory of Open Access Journals (Sweden)

    Iordache Vlad

    2018-01-01

    Full Text Available In urban environment, various heating ventilation and air conditioning appliances designed to maintain indoor comfort become urban acoustic pollution vectors due to the sound energy produced by these equipment. The acoustic barriers are the recommended method for the sound energy reduction in urban environment. The current sizing method of these acoustic barriers is too difficult and it is not practical for any 3D location of the noisy equipment and reception point. In this study we will develop based on the same method a new simplified tool for acoustic barriers sizing, maintaining the same precision characteristic to the classical method. Abacuses for acoustic barriers sizing are built that can be used for different 3D locations of the source and the reception points, for several frequencies and several acoustic barrier heights. The study case presented in the article represents a confirmation for the rapidity and ease of use of these abacuses in the design of the acoustic barriers.

  8. Urban sound energy reduction by means of sound barriers

    Science.gov (United States)

    Iordache, Vlad; Ionita, Mihai Vlad

    2018-02-01

    In urban environment, various heating ventilation and air conditioning appliances designed to maintain indoor comfort become urban acoustic pollution vectors due to the sound energy produced by these equipment. The acoustic barriers are the recommended method for the sound energy reduction in urban environment. The current sizing method of these acoustic barriers is too difficult and it is not practical for any 3D location of the noisy equipment and reception point. In this study we will develop based on the same method a new simplified tool for acoustic barriers sizing, maintaining the same precision characteristic to the classical method. Abacuses for acoustic barriers sizing are built that can be used for different 3D locations of the source and the reception points, for several frequencies and several acoustic barrier heights. The study case presented in the article represents a confirmation for the rapidity and ease of use of these abacuses in the design of the acoustic barriers.

  9. Herbal medicines that benefit epidermal permeability barrier function

    Directory of Open Access Journals (Sweden)

    Lizhi Hu

    2015-06-01

    Full Text Available Epidermal permeability barrier function plays a critical role in regulating cutaneous functions. Hence, researchers have been searching for effective and affordable regimens to enhance epidermal permeability barrier function. In addition to topical stratum corneum lipids, peroxisome proliferator-activated receptor, and liver X receptor ligands, herbal medicines have been proven to benefit epidermal permeability barrier function in both normal and diseased skin, including atopic dermatitis, glucocorticoid-induced skin damage, and UVB-damaged skin. The potential mechanisms by which herbal medicines improve the permeability barrier include stimulation of epidermal differentiation, lipid production, antimicrobial peptide expression, and antioxidation. Therefore, utilization of herbal medicines could be a valuable alternative approach to enhance epidermal permeability barrier function in order to prevent and/or treat skin disorders associated with permeability barrier abnormalities.

  10. Recent results from TMX-U thermal barrier experiments

    International Nuclear Information System (INIS)

    Molvik, A.W.; Allen, S.; Barter, J.

    1984-01-01

    The Tandem Mirror Experiment-Upgrade (TMX-U) device was designed to study plasma confinement in a tandem mirror with thermal barriers. Previously the author reported improved axial confinement with high end-plug potentials, consistent with thermal barrier operation. Now, the existence of thermal barriers in TMX-U confirmed by measuring the axial potential profile. Specifically, measured the change in energy of a 5-keV deuterium neutral beam that is injected nearly parallel to the axis and is ionized between the barrier and the central cell. The authors found that the barrier potential is lower than the central cell potential, as required for a thermal barrier. The peak potential is at least 2.4 keV, as determined from the minimum energy of end loss ions. In addition, radial transport is reduced by the use of floating and electrodes that map to concentric cylinders in the central cell. Sloshing ions continue to be microstable

  11. Barriers to participation in vocational orientation programmes among prisoners

    Directory of Open Access Journals (Sweden)

    Dorien Brosens

    2015-11-01

    Full Text Available This study investigates the barriers to prisoners’ participation in vocational education, as well as the predictors of different types of barriers. Survey data derived from a project in a remand prison in Belgium (N=468 provided the empirical evidence for the analyses. The results indicate that facing situational and informational barriers are most common. Based on the different kinds of barriers, various types of non-participants can be distinguished and multinomial logistic regression analyses are conducted to identify in what way participants of vocational education differ from various types of non-participants. For instance, prisoners with a poor understanding of the Dutch language and those who never/rarely receive visitors participate less in vocational education as they are more likely to be confronted with informational barriers. We conclude this article by discussing paths for future research and implications for policy and practice to anticipate the barriers for those who want to participate in vocational education.

  12. ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

    Energy Technology Data Exchange (ETDEWEB)

    R. Jarek

    2005-08-29

    The purpose of this model report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The resulting seepage evaporation and gas abstraction models are used in the total system performance assessment for the license application (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2005 [DIRS 173782], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports. To be consistent with other project documents that address features, events, and processes (FEPs), Table 6.14.1 of the current report includes updates to FEP numbers and FEP subjects for two FEPs identified in the technical work plan (TWP) governing this report (BSC 2005 [DIRS 173782]). FEP 2.1.09.06.0A (Reduction-oxidation potential in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP 2.1.09.06.0B (Reduction-oxidation potential in Drifts; see Table 6.14-1). FEP 2.1.09.07.0A (Reaction kinetics in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP 2.1.09.07.0B (Reaction kinetics in Drifts; see Table 6.14-1). These deviations from the TWP are justified because they improve integration with FEPs

  13. ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

    International Nuclear Information System (INIS)

    R. Jarek

    2005-01-01

    The purpose of this model report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The resulting seepage evaporation and gas abstraction models are used in the total system performance assessment for the license application (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2005 [DIRS 173782], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports. To be consistent with other project documents that address features, events, and processes (FEPs), Table 6.14.1 of the current report includes updates to FEP numbers and FEP subjects for two FEPs identified in the technical work plan (TWP) governing this report (BSC 2005 [DIRS 173782]). FEP 2.1.09.06.0A (Reduction-oxidation potential in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP 2.1.09.06.0B (Reduction-oxidation potential in Drifts; see Table 6.14-1). FEP 2.1.09.07.0A (Reaction kinetics in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP 2.1.09.07.0B (Reaction kinetics in Drifts; see Table 6.14-1). These deviations from the TWP are justified because they improve integration with FEPs documents. The updates

  14. Unified Model of Dynamic Forced Barrier Crossing in Single Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Friddle, R W

    2007-06-21

    Thermally activated barrier crossing in the presence of an increasing load can reveal kinetic rate constants and energy barrier parameters when repeated over a range of loading rates. Here we derive a model of the mean escape force for all relevant loading rates--the complete force spectrum. Two well-known approximations emerge as limiting cases; one of which confirms predictions that single-barrier spectra should converge to a phenomenological description in the slow loading limit.

  15. K West basin isolation barrier leak rate test

    International Nuclear Information System (INIS)

    Whitehurst, R.; McCracken, K.; Papenfuss, J.N.

    1994-01-01

    This document establishes the procedure for performing the acceptance test on the two isolation barriers being installed in K West basin. This acceptance test procedure shall be used to: First establish a basin water loss rate prior to installation of the two isolation barriers between the main basin and the discharge chute in K-Basin West. Second, perform an acceptance test to verify an acceptable leakage rate through the barrier seals

  16. Barriers to medication error reporting among hospital nurses.

    Science.gov (United States)

    Rutledge, Dana N; Retrosi, Tina; Ostrowski, Gary

    2018-03-01

    The study purpose was to report medication error reporting barriers among hospital nurses, and to determine validity and reliability of an existing medication error reporting barriers questionnaire. Hospital medication errors typically occur between ordering of a medication to its receipt by the patient with subsequent staff monitoring. To decrease medication errors, factors surrounding medication errors must be understood; this requires reporting by employees. Under-reporting can compromise patient safety by disabling improvement efforts. This 2017 descriptive study was part of a larger workforce engagement study at a faith-based Magnet ® -accredited community hospital in California (United States). Registered nurses (~1,000) were invited to participate in the online survey via email. Reported here are sample demographics (n = 357) and responses to the 20-item medication error reporting barriers questionnaire. Using factor analysis, four factors that accounted for 67.5% of the variance were extracted. These factors (subscales) were labelled Fear, Cultural Barriers, Lack of Knowledge/Feedback and Practical/Utility Barriers; each demonstrated excellent internal consistency. The medication error reporting barriers questionnaire, originally developed in long-term care, demonstrated good validity and excellent reliability among hospital nurses. Substantial proportions of American hospital nurses (11%-48%) considered specific factors as likely reporting barriers. Average scores on most barrier items were categorised "somewhat unlikely." The highest six included two barriers concerning the time-consuming nature of medication error reporting and four related to nurses' fear of repercussions. Hospitals need to determine the presence of perceived barriers among nurses using questionnaires such as the medication error reporting barriers and work to encourage better reporting. Barriers to medication error reporting make it less likely that nurses will report medication

  17. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Hampikian, J.M.; Carter, W.B. [Georgia Institute of Technology, Atlanta, GA (United States)

    1995-10-01

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  18. Barriers to guideline-compliant psoriasis care: analyses and concepts.

    Science.gov (United States)

    Eissing, L; Radtke, M A; Zander, N; Augustin, M

    2016-04-01

    Despite the availability of effective therapeutics and evidence-based treatment guidelines, a substantial proportion of patients with moderate-to-severe psoriasis does not receive appropriate care. This under-provision of health care may cause further worsening of health, remarkable limitations of the patient's quality of life, and indirect costs for the health care system. In order to provide guideline-compliant care for every psoriasis patient, it is important to identify barriers obstructing optimal care. Studies have identified various barriers on the physician's and on the patient's side; however, respective studies approached only single barriers, and not all of them in the context of psoriasis. Other publications that describe barriers systematically did not focus on psoriasis either. The objective of this literature review was to identify barriers and facilitators, based on studies analysing quality of care and single barriers, resulting in a comprehensive model of causal factors. Our analyses revealed three categories of barriers - patient-related, physician-related and external factors: On the patient side, we found non-adherence to therapies to be an important barrier, often in close association with psychiatric factors. Barriers on the physician's side predominantly are incomplete knowledge of the guidelines as well as the complexity of psoriasis comorbidity. In some countries, payment for patients with complex disease status is poor and inconsistent reimbursement regulations potentially interfere with optimal care. The current analysis indicates that most barriers are interdependent. Thus, measures approaching related barriers simultaneously are required. To improve care for psoriasis patients, further studies systematically addressing all potentially relevant barriers in conjoint are needed. © 2015 European Academy of Dermatology and Venereology.

  19. Anti-collimation of ballistic electrons by a potential barrier

    Science.gov (United States)

    Coleridge, P. T.; Taylor, R. P.; Sachrajda, A. S.; Adams, J. A.

    1994-03-01

    A pair of Quantum Point Contacts separated by a continuous barrier have been fabricated using the surface gate technique. Transport measurements for each component of this system and for various combinations have shown both additive and non-additive behaviour. The results are explained by a combination of reflection by the barrier of electrons collimated by the Quantum Point Contacts and transport by diffusion across the barrier.

  20. Test device for measuring permeability of a barrier material

    Science.gov (United States)

    Reese, Matthew; Dameron, Arrelaine; Kempe, Michael

    2014-03-04

    A test device for measuring permeability of a barrier material. An exemplary device comprises a test card having a thin-film conductor-pattern formed thereon and an edge seal which seals the test card to the barrier material. Another exemplary embodiment is an electrical calcium test device comprising: a test card an impermeable spacer, an edge seal which seals the test card to the spacer and an edge seal which seals the spacer to the barrier material.

  1. Selection of barrier metals for a waste package in tuff

    International Nuclear Information System (INIS)

    Russell, E.W.; McCright, R.D.; O'Neal, W.C.

    1983-10-01

    The Nevada Nuclear Waste Storage Investigations (NNWSI) project under the Civilian Radioactive Waste Management Program is planning a repository at Yucca Mountain at the Nevada Test Site for isolation of high-level nuclear waste. Lawrence Livermore National Laboratory is developing designs for an engineered barrier system containing several barriers such as the waste form, a canister and/or an overpack, packing, and near field host rock. In this paper we address the selection of metal containment barriers. 13 references, 4 tables

  2. "Targeted disruption of the epithelial-barrier by Helicobacter pylori"

    Directory of Open Access Journals (Sweden)

    Wroblewski Lydia E

    2011-11-01

    Full Text Available Abstract Helicobacter pylori colonizes the human gastric epithelium and induces chronic gastritis, which can lead to gastric cancer. Through cell-cell contacts the gastric epithelium forms a barrier to protect underlying tissue from pathogenic bacteria; however, H. pylori have evolved numerous strategies to perturb the integrity of the gastric barrier. In this review, we summarize recent research into the mechanisms through which H. pylori disrupts intercellular junctions and disrupts the gastric epithelial barrier.

  3. Universal potential-barrier penetration by initially confined wave packets

    International Nuclear Information System (INIS)

    Granot, Er'el; Marchewka, Avi

    2007-01-01

    The dynamics of an initially sharp-boundary wave packet in the presence of an arbitrary potential barrier is investigated. It is shown that the penetration through the barrier is universal in the sense that it depends only on the values of the wave function and its derivatives at the boundary. The dependence on the derivatives vanishes at long distances from the barrier, where the dynamics is governed solely by the initial value of the wave function at the boundary

  4. Universal potential-barrier penetration by initially confined wave packets

    Science.gov (United States)

    Granot, Er'El; Marchewka, Avi

    2007-07-01

    The dynamics of an initially sharp-boundary wave packet in the presence of an arbitrary potential barrier is investigated. It is shown that the penetration through the barrier is universal in the sense that it depends only on the values of the wave function and its derivatives at the boundary. The dependence on the derivatives vanishes at long distances from the barrier, where the dynamics is governed solely by the initial value of the wave function at the boundary.

  5. Reflectionlessness, kurtosis and top curvature of potential barriers

    International Nuclear Information System (INIS)

    Ahmed, Zafar

    2006-01-01

    Apart from the rectangular barrier, other barriers having a single maximum generally display reflectivity, R(E), as a smoothly decreasing function of energy. We conjecture that symmetric potential barriers with a single maximum entail zeros or sharp minima in R(E) provided they have either their coefficient of kurtosis lying in the range (1.8, 3.0), or their top curvature as zero, or both

  6. Improved anchoring of SSS with vacuum barrier to avoid displacement

    CERN Document Server

    Capatina, O; Foreste, A; Parma, V; Renaglia, T; Quesnel, J

    2009-01-01

    As presented in the previous speech, the incident in sector 3-4 of the LHC caused a high pressure build-up inside the cryostat insulation vacuum resulting in high longitudinal forces acting on the insulation vacuum barriers. This resulted in braking floor and floor fixations of the SSS with vacuum barrier. The strategy of improving anchoring of SSS with vacuum barrier to avoid displacement is presented and discussed.

  7. Women leadership barriers in healthcare, academia and business

    OpenAIRE

    Kalaitzi, S.; Czabanowska, K.; Fowler-Davis, S.; Brand, H.

    2017-01-01

    Purpose\\ud \\ud \\ud \\ud This paper maps the barriers to women leadership across healthcare, academia and business, and identifies barriers prevalence across sectors. A Barriers Thematic Map (BTM), with quantitative logic, and a prevalence chart have been developed, with the aim to uncover inequalities and provide orientation to develop inclusion and equal opportunity strategies within different work environments.\\ud \\ud \\ud \\ud \\ud Design/methodology/approach\\ud \\ud \\ud A systematic literature...

  8. Selected socioeconomic barriers of education in Sub-Saharan Africa

    OpenAIRE

    Tillová, Petra

    2015-01-01

    Selected socioeconomic barriers of education in Sub-Saharan Africa Abstract The aim of bachelor thesis is to describe and understand the process of education in Sub-Saharan Africa and analyze components that cause limited access to education. The first part of the thesis describes the process of education in Sub-Saharan Africa using selected indicators. The second main part focuses on the description and possible relations between selected socioeconomic barriers and literacy. Selected barrier...

  9. Selection of barrier metals for a waste package in tuff

    International Nuclear Information System (INIS)

    Russell, E.W.; McCright, R.D.; O'Neal, W.C.

    1983-09-01

    The Nevada Nuclear Waste Storage Investigation (NNWSI) project under the Civilian Radioactive Waste Management Program is planning a repository at Yucca Mountain at the Nevada Test Site for isolation of high-level nuclear waste. LLNL is developing designs for an engineered barrier system containing several barriers such as the waste form, a canister and/or an overpack, packing, and near field host rock. The selection of metal containment barriers is addressed. 13 references

  10. Niobium nitride Josephson junctions with silicon and germanium barriers

    International Nuclear Information System (INIS)

    Cukauskas, E.J.; Carter, W.L.

    1988-01-01

    Niobium nitride based junctions with silicon, germanium, and composite silicon/germanium barriers were fabricated and characterized for several barrier compositions. The current-voltage characteristics were analyzed at several temperatures using the Simmons model and numerical integration of the WKB approximation for the average barrier height and effective thickness. The zero voltage conductance was measured from 1.5 K to 300 K and compared to the Mott hopping conductivity model and the Stratton tunneling temperature dependence. Conductivity followed Mott conductivity at temperatures above 60 K for junctions with less than 100 angstrom thick barriers

  11. PRIORITISING LEAN CONSTRUCTION BARRIERS IN UGANDA'S CONSTRUCTION INDUSTRY

    Directory of Open Access Journals (Sweden)

    Henry Mwanaki Alinaitwe

    2009-06-01

    Full Text Available Engaging in lean construction efforts could prove to be highly rewarding for building firms in Uganda. However, lean construction is risky and can be disastrous if not properly managed. Lean production efforts in some other countries have not been successful due to the many barriers to its successful implementation. To enable sound lean construction efforts and to increase the chances of success in eliminating waste, a thorough investigation of the barriers is essential. This study presents 31 barriers and investigates their influence (strength on the success of lean construction initiatives. Structured interviews were carried out with technical managers of building firms to assess their perception of the barriers to lean production based on their experience at their firms. The strongest barrier is the provision of inputs exactly when required. Additionally, the barriers were ranked according to the ease of overcoming each. The easiest barrier to overcome is keeping the required items in the right place. Finally, a graphical aid is provided to enable decision makers to concentrate their efforts on the influential (strong, yet easy to overcome barriers. A lack of buildable designs and a participative management style for the workforce are the most important barriers to successful waste reduction in terms of strength and ease of overcoming. On the other hand, a lack of an organisational culture that supports teamwork, a lack of prefabrication and a lack of knowledgeable and skilled workers are regarded as low in strength, and at the same time difficult to overcome.

  12. Effect of contact barrier on electron transport in graphene.

    Science.gov (United States)

    Zhou, Yang-Bo; Han, Bing-Hong; Liao, Zhi-Min; Zhao, Qing; Xu, Jun; Yu, Da-Peng

    2010-01-14

    The influence of the barrier between metal electrodes and graphene on the electrical properties was studied on a two-electrode device. A classical barrier model was used to analyze the current-voltage characteristics. Primary parameters including barrier height and effective resistance were achieved. The electron transport properties under magnetic field were further investigated. An abnormal peak-valley-peak shape of voltage-magnetoresistance curve was observed. The underlying mechanisms were discussed under the consideration of the important influence of the contact barrier. Our results indicate electrical properties of graphene based devices are sensitive to the contact interface.

  13. Protective barrier systems for final disposal of Hanford Waste Sites

    International Nuclear Information System (INIS)

    Phillips, S.J.; Hartley, J.N.

    1986-01-01

    A protecting barrier system is being developed for potential application in the final disposal of defense wastes at the Hanford Site. The functional requirements for the protective barrier are control of water infiltration, wind erosion, and plant and animal intrusion into the waste zone. The barrier must also be able to function without maintenance for the required time period (up to 10,000 yr). This paper summarizes the progress made and future plans in this effort to design and test protective barriers at the Hanford Site

  14. COMPASS: A source term code for investigating capillary barrier performance

    International Nuclear Information System (INIS)

    Zhou, Wei; Apted, J.J.

    1996-01-01

    A computer code COMPASS based on compartment model approach is developed to calculate the near-field source term of the High-Level-Waste repository under unsaturated conditions. COMPASS is applied to evaluate the expected performance of Richard's (capillary) barriers as backfills to divert infiltrating groundwater at Yucca Mountain. Comparing the release rates of four typical nuclides with and without the Richard's barrier, it is shown that the Richard's barrier significantly decreases the peak release rates from the Engineered-Barrier-System (EBS) into the host rock

  15. Concrete road barriers subjected to impact loads: An overview

    Directory of Open Access Journals (Sweden)

    Muhammad Fauzi Bin Mohd. Zain

    Full Text Available Abstract Concrete barriers prevent vehicles from entering the opposite lane and going off the road. An important factor in the design of concrete barriers is impact load, which a vehicle exerts upon collision with a concrete barrier. This study suggests that a height of 813 mm, a base width of 600 mm, and a top width of 240 mm are optimum dimensions for a concrete barrier. These dimensions ensure the stability of concrete barriers during vehicle collisions. An analytical and experimental model is used to analyze the concrete barrier design. The LS-DYNA software is utilized to create the analytical models because it can effectively simulate vehicle impact on concrete barriers. Field tests are conducted with a vehicle, whereas laboratory tests are conducted with machines that simulate collisions. Full-scale tests allow the actual simulation of vehicle collisions with concrete barriers. In the vehicle tests, a collision angle of 25°, collision speeds of 100 km per hour, and a vehicle weighing more than 2 t are considered in the reviewed studies. Laboratory tests are performed to test bridge concrete barriers in static condition.

  16. Electron optics with magnetic vector potential barriers in graphene

    International Nuclear Information System (INIS)

    Ghosh, Sankalpa; Sharma, Manish

    2009-01-01

    An analysis of electron transport in graphene in the presence of various arrangements of delta-function like magnetic barriers is presented. The motion through one such barrier gives an unusual non-specular refraction leading to asymmetric transmission. The symmetry is restored by putting two such barriers in opposite directions side by side. Periodic arrangements of such barriers can be used as Bragg reflectors whose reflectivity has been calculated using a transfer matrix formalism. Such Bragg reflectors can be used to make resonant cavities. We also analyze the associated band structure for the case of infinite periodic structures. (fast track communication)

  17. High-resolution reconstruction of a coastal barrier system

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel; Andersen, Thorbjørn Joest; Nielsen, Lars Henrik

    2015-01-01

    This study presents a detailed reconstruction of the sedimentary effects of Holocene sea-level rise on a modern coastal barrier system (CBS). Increasing concern over the evolution of CBSs due to future accelerated rates of sea-level rise calls for a better understanding of coastal barriers response...... from retreat of the barrier island and probably also due to formation of a tidal inlet close to the study area. Continued transgression and shoreface retreat created a distinct hiatus and wave ravinement surface in the seaward part of the CBS before the barrier shoreline stabilised between 5.0 and 4...

  18. Evaluation of Erosion Resistance of Advanced Turbine Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Kuczmarski, Maria A.; Miller, Robert A.; Cuy, Michael D.

    2007-01-01

    The erosion resistant turbine thermal barrier coating system is critical to aircraft engine performance and durability. By demonstrating advanced turbine material testing capabilities, we will be able to facilitate the critical turbine coating and subcomponent development and help establish advanced erosion-resistant turbine airfoil thermal barrier coatings design tools. The objective of this work is to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and/or thermal gradient environments, validating advanced turbine airfoil thermal barrier coating systems based on nano-tetragonal phase toughening design approaches.

  19. Experienced Barriers to Lean in Swedish Manufacturing and Health Care

    Directory of Open Access Journals (Sweden)

    Bengt Halling

    2013-12-01

    Full Text Available The purpose is to compare similarities and divergences in how the concepts of Lean and barriers to Lean are described by key informants at a production unit in a large manufacturing company and two emergency health care units in Sweden. Data was collected via semi-structured interviews and analyzed with the constant comparative method (CCM and Porras and Robertson’s (1992 change model. : In both organizations, the view of Lean changed from a toolbox to a human behavior view. Eight barriers were experienced in both organizations. Three barriers were unique to manufacturing or to health care, respectively. Nine barriers were elements of social factors; five were elements of organizing arrangements. Only people practically involved and responsible for the implementation at the two organizations participated in the study. Persons responsible for implementing Lean should consider organizational arrangements and social factors in order to limit barriers to successful implementation. Most research on Lean has been about successful Lean implementations. This study focuses on how Lean is viewed and what barriers personnel in manufacturing and health care have experienced. In comparing the barriers to Lean experienced in the two groups, common, archetypical, and unique barriers for manufacturing and health care can be identified, thus contributing to knowledge about barriers to Lean implementation.

  20. Quasi-relativistic effects in barrier-penetration processes

    International Nuclear Information System (INIS)

    Anchishkin, D.V.

    1991-01-01

    The problem of a particle tunneling through the potential barrier is solved within quasi-relativistic Schroedinger equation. It is shown that the subbarrier relativistic effects give a significant addition to penetration coefficient when some relations between parameters of the barrier and mass of a tunneling particle are satisfied. For instance an account of these effects for penetration of low energy π + -mesons through Coulomb barrier of the 298 U nuclei would give the increasing of penetration coefficient to 30 percent as compared to the nonrelativistic one. Also we give the criteria under which the contribution of the ''under barrier relativism'' to penetration coefficient becomes essential. 3 refs.; 6 figs. (author)

  1. Electrical insulator assembly with oxygen permeation barrier

    Science.gov (United States)

    Van Der Beck, Roland R.; Bond, James A.

    1994-01-01

    A high-voltage electrical insulator (21) for electrically insulating a thermoelectric module (17) in a spacecraft from a niobium-1% zirconium alloy wall (11) of a heat exchanger (13) filled with liquid lithium (16) while providing good thermal conductivity between the heat exchanger and the thermoelectric module. The insulator (21) has a single crystal alumina layer (SxAl.sub.2 O.sub.3, sapphire) with a niobium foil layer (32) bonded thereto on the surface of the alumina crystal (26) facing the heat exchanger wall (11), and a molybdenum layer (31) bonded to the niobium layer (32) to act as an oxygen permeation barrier to preclude the oxygen depleting effects of the lithium from causing undesirable niobium-aluminum intermetallic layers near the alumina-niobium interface.

  2. Barriers to emergency obstetric care services

    DEFF Research Database (Denmark)

    Echoka, Elizabeth; Makokha, Anselimo; Dubourg, Dominique

    2014-01-01

    Introduction: Pregnancy-related mortality and morbidity in most low and middle income countries can be reduced through early recognition of complications, prompt access to care and appropriate medical interventions following obstetric emergencies. We used the three delays framework to explore...... barriers to emergency obstetric care (EmOC) services by women who experienced life threatening obstetric complications in Malindi District, Kenya. Methods: A facility-based qualitative study was conducted between November and December 2010. In-depth interviews were conducted with 30 women who experienced...... decision to seek care and in reaching an appropriate care facility. The "first" delay was due to lack of birth preparedness, including failure to identify a health facility for delivery services regardless of antenatal care and to seek care promptly despite recognition of danger signs. The "second" delay...

  3. Quantum mechanical streamlines. I - Square potential barrier

    Science.gov (United States)

    Hirschfelder, J. O.; Christoph, A. C.; Palke, W. E.

    1974-01-01

    Exact numerical calculations are made for scattering of quantum mechanical particles hitting a square two-dimensional potential barrier (an exact analog of the Goos-Haenchen optical experiments). Quantum mechanical streamlines are plotted and found to be smooth and continuous, to have continuous first derivatives even through the classical forbidden region, and to form quantized vortices around each of the nodal points. A comparison is made between the present numerical calculations and the stationary wave approximation, and good agreement is found between both the Goos-Haenchen shifts and the reflection coefficients. The time-independent Schroedinger equation for real wavefunctions is reduced to solving a nonlinear first-order partial differential equation, leading to a generalization of the Prager-Hirschfelder perturbation scheme. Implications of the hydrodynamical formulation of quantum mechanics are discussed, and cases are cited where quantum and classical mechanical motions are identical.

  4. Ceramides and barrier function in healthy skin

    DEFF Research Database (Denmark)

    Mutanu Jungersted, Jakob; Hellgren, Lars; Høgh, Julie Kaae

    2010-01-01

    Lipids in the stratum corneum are key components in the barrier function of the skin. Changes in lipid composition related to eczematous diseases are well known, but limited data are available on variations within healthy skin. The objective of the present study was to compare ceramide subgroups...... and ceramide/cholesterol ratios in young, old, male and female healthy skin. A total of 55 participants with healthy skin was included in the study. Lipid profiles were correlated with transepidermal water loss and with information on dry skin from a questionnaire including 16 people. No statistically...... significant differences were found between young and old skin for ceramide subgroups or ceramide/cholesterol ratios, and there was no statistically significant correlation between answers about dry skin and ceramide levels. Interestingly, a statistically significant higher ceramide/cholesterol ratio was found...

  5. Rotavirus vaccination in Europe: drivers and barriers.

    Science.gov (United States)

    Parez, N; Giaquinto, C; Du Roure, C; Martinon-Torres, F; Spoulou, V; Van Damme, P; Vesikari, T

    2014-05-01

    Rotavirus gastroenteritis is a vaccine-preventable disease that confers a high medical and economic burden in more developed countries and can be fatal in less developed countries. Two vaccines with high efficacy and good safety profiles were approved and made available in Europe in 2006. We present an overview of the status of rotavirus vaccination in Europe. We discuss the drivers (including high effectiveness and effect of universal rotavirus vaccination) and barriers (including low awareness of disease burden, perception of unfavourable cost-effectiveness, and potential safety concerns) to the implementation of universal rotavirus vaccination in Europe. By February, 2014, national universal rotavirus vaccination had been implemented in Belgium, Luxembourg, Austria, Finland, Greece, Luxembourg, Norway, and the UK. Four other German states have issued recommendations and reimbursement is provided by sickness funds. Other countries were at various stages of recommending or implementing universal rotavirus vaccination. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Proton emission with a screened electrostatic barrier

    Energy Technology Data Exchange (ETDEWEB)

    Budaca, R. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania); Academy of Romanian Scientists, Bucharest (Romania); Budaca, A.I. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania)

    2017-08-15

    Half-lives of proton emission for Z ≥ 51 nuclei are calculated within a simple analytical model based on the WKB approximation for the barrier penetration probability which includes the centrifugal and overlapping effects besides the electrostatic repulsion. The model has a single free parameter associated to a Hulthen potential which emulates a Coulomb electrostatic interaction only at short distance. The agreement with experimental data is very good for most of the considered nuclei. Theoretical predictions are made for few cases with uncertain emitting state configuration or incomplete decay information. The model's assignment of the proton orbital momentum is in agreement with the differentiation of the experimental data by orbital momentum values realized with a newly introduced correlation formula. (orig.)

  7. Market Opportunities and Barriers for Smart Buildings

    DEFF Research Database (Denmark)

    Ma, Zheng; Badi, Adrian; Jørgensen, Bo Nørregaard

    2016-01-01

    Buildings consume up to 42% of the global electricity and the primary emitter of greenhouse gas on the planet. Building efficiency is the largest growing segment in the US, the estimated global revenue by the building efficiency sector is around 210 million dollars, and constantly increases since...... 2011. Much research already shows the players' passive and conservative attitudes to enter into the energy efficiency market. Especially there are obstacles for the construction companies to redesign their business model from the traditional building business to the smart building market. This paper...... conducts a qualitative approach with primary and secondary data to investigate the Barriers and opportunities of the construction companies into the smart building market. The result shows the willingness of the players to involve the building efficiency business with huge potential monetary benefits...

  8. Thermal barrier coatings - Technology for diesel engines

    International Nuclear Information System (INIS)

    Harris, D.H.; Lutz, J.

    1988-01-01

    Thermal Barrier Coatings (TBC) are a development of the aerospace industry primarily aimed at hot gas flow paths in turbine engines. TBC consists of zirconia ceramic coatings applied over (M)CrAlY. These coatings can provide three benefits: (1) a reduction of metal surface operating temperatures, (2) a deterrent to hot gas corrosion, and (3) improved thermal efficiencies. TBC brings these same benefits to reciprocal diesel engines but coating longevity must be demonstrated. Diesels require thicker deposits and have challenging geometries for the arc-plasma spray (APS) deposition process. Different approaches to plasma spraying TBC are required for diesels, especially where peripheral edge effects play a major role. Bondcoats and ceramic top coats are modified to provide extended life as determined by burner rig tests, using ferrous and aluminum substrates

  9. Overcoming immunological barriers in regenerative medicine.

    Science.gov (United States)

    Zakrzewski, Johannes L; van den Brink, Marcel R M; Hubbell, Jeffrey A

    2014-08-01

    Regenerative therapies that use allogeneic cells are likely to encounter immunological barriers similar to those that occur with transplantation of solid organs and allogeneic hematopoietic stem cells (HSCs). Decades of experience in clinical transplantation hold valuable lessons for regenerative medicine, offering approaches for developing tolerance-induction treatments relevant to cell therapies. Outside the field of solid-organ and allogeneic HSC transplantation, new strategies are emerging for controlling the immune response, such as methods based on biomaterials or mimicry of antigen-specific peripheral tolerance. Novel biomaterials can alter the behavior of cells in tissue-engineered constructs and can blunt host immune responses to cells and biomaterial scaffolds. Approaches to suppress autoreactive immune cells may also be useful in regenerative medicine. The most innovative solutions will be developed through closer collaboration among stem cell biologists, transplantation immunologists and materials scientists.

  10. Enablers & Barriers for Realizing Modularity Benefits

    DEFF Research Database (Denmark)

    Storbjerg, Simon Haahr; Brunø, Thomas Ditlev; Thyssen, Jesper

    2012-01-01

    far less attention compared to the theories and methods concerning modularization of technical systems. Harvesting the full potential of modularization, particularly in relation to product development agility, depends on more than an optimal architecture. Key enablers in this context......Although modularization is becoming both a well-described domain in academia and a broadly applied concept in business, many of today’s firm still struggle to realize the promised benefits of this approach. Managing modularization is a complex matter, and in spite of this, a topic that has received...... are the organizational and systems related aspects. Recognizing the need for guidance to realize the benefits of modularity, the purpose of this study is through a literature study and a case study to improve the insight into the organizational and systems related enablers and barriers with regard to obtaining the full...

  11. Nanoparticle transport across the blood brain barrier.

    Science.gov (United States)

    Grabrucker, Andreas M; Ruozi, Barbara; Belletti, Daniela; Pederzoli, Francesca; Forni, Flavio; Vandelli, Maria Angela; Tosi, Giovanni

    2016-01-01

    While the role of the blood-brain barrier (BBB) is increasingly recognized in the (development of treatments targeting neurodegenerative disorders, to date, few strategies exist that enable drug delivery of non-BBB crossing molecules directly to their site of action, the brain. However, the recent advent of Nanomedicines may provide a potent tool to implement CNS targeted delivery of active compounds. Approaches for BBB crossing are deeply investigated in relation to the pathology: among the main important diseases of the CNS, this review focuses on the application of nanomedicines to neurodegenerative disorders (Alzheimer, Parkinson and Huntington's Disease) and to other brain pathologies as epilepsy, infectious diseases, multiple sclerosis, lysosomal storage disorders, strokes.

  12. Improved permeation barriers for tritiated waste packaging

    International Nuclear Information System (INIS)

    Vassallo, G.; Van Den Bergh, R.; Forcey, K.S.; Perujo, A.

    1994-01-01

    High-density polyethylene (HDPE) is extensively used as flexible bagging or packaging for soft tritiated waste in the tritium community because of its low permeability to the more radiotoxic form of tritium, i.e., tritiated water (HTO). However, HDPE does not represent a perfect barrier to HTO nor does it effectively hinder the permeation of elemental tritium, i.e, HT. This latter drawback is particularly important considering that the elemental form may readily convert to HTO outside of the waste package. The possible use of a multilayer film as packing material for the conditioning of tritiated waste is assessed, and its capability to hinder the permeation of elemental tritium is measured and compared with that of bare HDPE. The material investigated is readily available from the food industry. 5 refs., 1 tab

  13. Barriers of the Human Capital Shaping

    Directory of Open Access Journals (Sweden)

    Joanna Krochmal

    2011-07-01

    Full Text Available Nowadays, in the age of the economy focused on knowledge and science, the process of formation and development of the employees is considered as a very important investment, inspiration and a tool to efficiency creating, success and first of all, the strategic potential of the company. Indeed, it is people who are the key and the path to success and on them, the strength, the power and the success of any business should be built. The aim of this elaboration is to highlight and emphasize the importance of investment in human capital and show fluctuations, as one of the barriers that can disrupt this development, what in general also may be caused by lack of adequate systems of employees motivation.

  14. Maximizing competition : reducing barriers for new players

    International Nuclear Information System (INIS)

    Chandler, H.; Cramer, D.; McLeese, R.; Singer, J.

    2003-01-01

    This session included highlights from four guest speakers who commented on ways to reduce barriers to competition in Ontario's electric power industry. Topics of discussion included intertie transaction failures, the lack of overall investment in the market, the government's inaction which is preventing investment, the continued underwriting of Ontario Power Generation's activities by the government which discourages investment in the private sector, and indecisiveness regarding policy on coal plants. It was emphasized that investors need to know for certain that they can get a reasonable rate of return on their investments, that the market will be transparent and there will be no shift in policy. The need to promote new, efficient power generation by means of nuclear, coal, natural gas, and hydro energy was also emphasized. Charts depicting total energy production by source were presented for 2001 with projections to 2012. figs

  15. Barriers to increased market-oriented activity

    DEFF Research Database (Denmark)

    Bisp, Søren

    1999-01-01

    and related activities still seem to attract relatively few resources is not answered by supplying another checklist or package of facilitators. Based on published conceptual writings and empirical studies this article makes an account of what the intra-organizational barriers may be to increased market......Most research on market orientation has dealt with assessing how market orientation behaviour is related to business performance. This work has established an intense market-oriented activity as significantly and positively related to business performance under most circumstances. In a maturing......-oriented activity. A framework of six generic domains is suggested: Organizational structure, human resource management, market-oriented activity competence, psychological climate, managers' personality characteristics, and individually held beliefs. A model is suggested inter-relating the domains....

  16. Immune barriers of Ebola virus infection.

    Science.gov (United States)

    McElroy, Anita K; Mühlberger, Elke; Muñoz-Fontela, César

    2018-02-01

    Since its initial emergence in 1976 in northern Democratic Republic of Congo (DRC), Ebola virus (EBOV) has been a global health concern due to its virulence in humans, the mystery surrounding the identity of its host reservoir and the unpredictable nature of Ebola virus disease (EVD) outbreaks. Early after the first clinical descriptions of a disease resembling a 'septic-shock-like syndrome', with coagulation abnormalities and multi-system organ failure, researchers began to evaluate the role of the host immune response in EVD pathophysiology. In this review, we summarize how data gathered during the last 40 years in the laboratory as well as in the field have provided insight into EBOV immunity. From molecular mechanisms involved in EBOV recognition in infected cells, to antigen processing and adaptive immune responses, we discuss current knowledge on the main immune barriers of infection as well as outstanding research questions. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. The role of the sediment barrier

    International Nuclear Information System (INIS)

    Freeman, T.J.; Schultheiss, P.J.; Searle, R.C.; Sills, G.C.; Toolan, F.E.

    1989-01-01

    The conference 'Disposal of radioactive wastes in seabed sediments' was organized by the Society for Underwater Technology to review the potential of certain seabed sediments to provide a long-term containment for radioactive wastes. Its objectives were to assess: (1) what has been learned about the properties and nature of the sediments of the deep ocean; (2) the merits and demerits of the conceptual techniques that have been developed to dispose of waste; and (3) whether what has been learned about deep ocean disposal has any relevance to other areas of marine science. This chapter introduces the subject matter of the conference in the framework of the international research programme and discusses what has been learned about the role of the sediment barrier. (author)

  18. Stratum Corneum Barrier Lipids in Cholesteatoma

    DEFF Research Database (Denmark)

    Svane-Knudsen, V; Halkier-Sørensen, L; Rasmussen, G

    2000-01-01

    emerged. When the corneocyte reaches the transitional stage to the stratum corneum, the Odland bodies accumulate near the cell membrane and discharge their contents of lipid and enzymes. The lipids are reorganized into multiple long sheets of lamellar structures that embrace the keratinized corneocytes......, as seen in the formation and maintenance of the cutaneous permeability barrier. In this study we draw the attention to the facts that the cholesteatoma epithelium is capable of producing not only cholesterol, but also several lipids, and that the lipid molecules are organized in multilamellar structures......Specimens from primary cholesteatomas were examined under the electron microscope using a lipid-retaining method that is best suited for intracellular lipids and a method that is best for intercellular lipids. In the stratum granulosum of the squamous epithelium, a large number of Odland bodies...

  19. [Emergency contraception in Brazil: facilitators and barriers].

    Science.gov (United States)

    Hardy, E; Duarte, G A; Osis, M J; Arce, X E; Possan, M

    2001-01-01

    A multi-centered qualitative study was conducted in Brazil, Chile, and Mexico to assess the acceptability of emergency contraception both among potential users and possible providers, authorities, and opinion-makers, and to identify (according to participants' perceptions) factors facilitating or hindering the method's use and the most appropriate strategies to disseminate information and provide the method. Data were collected through semi-structured interviews, group interviews, and discussion groups, which were tape-recorded and transcribed. A thematic analysis of this material was conducted. Acceptability of emergency contraception was high among participants, who also felt that there were no barriers towards its acceptance by the population. Participants felt that the method's acceptability would be greater if it were included in reproductive health programs, emphasizing its prescription for emergency situations. Participants highlighted that strategic components in Brazil would be training of providers and inclusion of the method in family planning services.

  20. Desensitization: Overcoming the Immunologic Barriers to Transplantation

    Science.gov (United States)

    Choi, Jua; Vo, Ashley; Peng, Alice; Jordan, Stanley C.

    2017-01-01

    HLA (Human Leucocyte Antigen) sensitization is a significant barrier to successful kidney transplantation. It often translates into difficult crossmatch before transplant and increased risk of acute and chronic antibody mediated rejection after transplant. Over the last decade, several immunomodulatory therapies have emerged allowing for increased access to kidney transplantation for the immunologically disadvantaged group of HLA sensitized end stage kidney disease patients. These include IgG inactivating agents, anti-cytokine antibodies, costimulatory molecule blockers, complement inhibitors, and agents targeting plasma cells. In this review, we discuss currently available agents for desensitization and provide a brief analysis of data on novel biologics, which will likely improve desensitization outcomes, and have potential implications in treatment of antibody mediated rejection. PMID:28127571