Digital Manufacturing of Selective Porous Barriers in Microchannels Using Multi-Material Stereolithography

Directory of Open Access Journals (Sweden)

Yong Tae Kim

2018-03-01

Full Text Available We have developed a sequential stereolithographic co-printing process using two different resins for fabricating porous barriers in microfluidic devices. We 3D-printed microfluidic channels with a resin made of poly(ethylene glycol diacrylate (MW = 258 (PEG-DA-258, a UV photoinitiator, and a UV sensitizer. The porous barriers were created within the microchannels in a different resin made of either PEG-DA (MW = 575 (PEG-DA-575 or 40% (w/w in water PEG-DA (MW = 700 (40% PEG-DA-700. We showed selective hydrogen ion diffusion across a 3D-printed PEG-DA-575 porous barrier in a cross-channel diffusion chip by observing color changes in phenol red, a pH indicator. We also demonstrated the diffusion of fluorescein across a 3D-printed 40% PEG-DA-700 porous barrier in a symmetric-channel diffusion chip by measuring fluorescence intensity changes across the porous barrier. Creating microfluidic chips with integrated porous barriers using a semi-automated 3D printing process shortens the design and processing time, avoids assembly and bonding complications, and reduces manufacturing costs compared to micromolding processes. We believe that our digital manufacturing method for fabricating selective porous barriers provides an inexpensive, simple, convenient and reproducible route to molecule delivery in the fields of molecular filtration and cell-based microdevices.

Plan for metal barrier selection and testing for NNWSI

International Nuclear Information System (INIS)

Halsey, W.G.; McCright, R.D.

1987-12-01

The Department of Energy's Nevada Nuclear Waste Storage Investigations (NNWSI) Project is evaluating a site at Yucca Mountain in Nevada as a geological repository for the storage of high-level nuclear waste. The Nuclear Waste Management Projects (NWMP) at Lawrence Livermore National Laboratory (LLNL) has the responsibility for design, testing, and performance analysis of the NNWSI waste packages. One portion of this work is the selection and testing of the material for container construction. The anticipated container design is for this material to be a corrosion resistant metal called the metal barrier. This document is the publication version of the Scientific Investigation Plan (SIP) for the Metal Barrier Selection and Testing Task. The SIP serves as a formal planning document for the investigation and is used to assign quality assurance levels to the activities of the task. This document is an informal version for information distribution and has the sections on ''Schedule and Milestones'' and the ''Quality Assurance Level Assignment Sheets'' removed

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

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.

Gas permeability of bentonite barriers: development, construction and testing of a measurement system

Directory of Open Access Journals (Sweden)

Heraldo Nunes Pitanga

Full Text Available Abstract This article proposes a testing device to quickly and reliably estimate the gas permeability of bentonite-based clay barriers used in landfill cover systems. The testing methodology is based on a transient gas flow regime that passes through the barrier, therefore not requiring the use of sophisticated equipment that aim to maintain constant differential pressure and measure the gas flow, common requirements for testing methods under a permanent flow regime. To confirm the feasibility of the proposed technique, tests were performed on a pure hydrated bentonite layer, which subsequently encompassed samples of geosynthetic clay liner (GCL at different moisture contents. Geosynthetic clay liners are often selected as a part of the barrier layer for cover systems in solid waste landfills to prevent infiltration of rainfall and migration of biogas into the atmosphere. The results confirmed the equipment reliability and differentiate the different responses of the gas flow barriers studied, considering their different compositions and different moistures.

Alternative approaches to reliability modeling of a multiple engineered barrier system

International Nuclear Information System (INIS)

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

1994-01-01

The lifetime of the engineered barrier system used for containment of high-level radioactive waste will significantly impact the total performance of a geological repository facility. Currently two types of designs are under consideration for an engineered barrier system, single engineered barrier system and multiple engineered barrier system. Multiple engineered barrier system consists of several metal barriers and the waste form (cladding). Some recent work show that a significant improvement of performance can be achieved by utilizing multiple engineered barrier systems. Considering sequential failures for each barrier, we model the reliability of the multiple engineered barrier system. Weibull and exponential lifetime distributions are used through out the analysis. Furthermore, the number of failed engineered barrier systems in a repository at a given time is modeled using a poisson approximation

Annotated bibliography of selected references on shoreline barrier island deposits with emphasis on Patrick Draw Field, Sweetwater County, Wyoming

Energy Technology Data Exchange (ETDEWEB)

Rawn-Schatzinger, V.; Schatzinger, R.A.

1993-07-01

This bibliography contains 290 annotated references on barrier island and associated depositional environments and reservoirs. It is not an exhaustive compilation of all references on the subject, but rather selected papers on barrier islands, and the depositional processes of formation. Papers that examine the morphology and internal architecture of barrier island deposits, exploration and development technologies are emphasized. Papers were selected that aid in understanding reservoir architecture and engineering technologies to help maximize recovery efficiency from barrier island oil reservoirs. Barrier islands from Wyoming, Montana and the Rocky Mountains basins are extensively covered.

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

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.

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.

Study on vibration behaviors of engineered barrier system

International Nuclear Information System (INIS)

Mikoshiba, Tadashi; Ogawa, Nobuyuki; Minowa, Chikahiro

1998-01-01

High-level radioactive wastes have been buried underground by packing into a strong sealed container made from carbon steel (over-pack) with buffer material (bentonite). The engineered barrier system constructed with an overpack and buffer materials must be resistant to earthquakes as well as invasion of groundwater for a long period. Therefore, seismic evaluation of barrier system for earthquakes is indispensable especially in Japan to keep its structural safety. Here, the effects of earthquake vibration on the engineered barrier systems were investigated experimentally. Random-wave vibration and practical seismic wave one were loaded for the systems and fundamental data were obtained. For the former vibration the response characteristics of both engineered barrier models constructed with overpack and bentonite were non-linear. For the latter one, the stress in bentonite was increased in proportion to the vibration level. (M.N.)

Interpretation of quasi-elastic barrier distributions for weakly bound systems

International Nuclear Information System (INIS)

Monteiro, D.S.; Gomes, P.R.S.; Lubian, J.

2009-01-01

Full text: We verify that quasi-elastic (elastic + inelastic) backscattering barrier distributions for weakly bound systems do not strictly correspond to fusion barrier distributions, but rather to reaction threshold distribution, as proposed by Zagrebaev in a recent paper concerning very heavy systems. In this work, we investigate whether Zagrebaevs interpretation is valid by comparing experimental results obtained in two very recent works with the 6 Li + 144 Sm system. Monteiro et al derived the quasi-elastic barrier distribution (or reaction threshold distribution, following Zagrebaevs interpretation) by adding elastic and inelastic backscattering for this system. Rath et al obtained fusion barrier distribution for the same system from the measured complete fusion cross section for the same system. We conclude that the quasi-elastic barrier distributions can be associated with fusion barrier distributions only in situations where there are no relevant reaction channels apart from fusion. This is not the situation for very heavy nor for weakly bound systems. (author)

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

Thermal model of attic systems with radiant barriers

Energy Technology Data Exchange (ETDEWEB)

Wilkes, K.E.

1991-07-01

This report summarizes the first phase of a project to model the thermal performance of radiant barriers. The objective of this phase of the project was to develop a refined model for the thermal performance of residential house attics, with and without radiant barriers, and to verify the model by comparing its predictions against selected existing experimental thermal performance data. Models for the thermal performance of attics with and without radiant barriers have been developed and implemented on an IBM PC/AT computer. The validity of the models has been tested by comparing their predictions with ceiling heat fluxes measured in a number of laboratory and field experiments on attics with and without radiant barriers. Cumulative heat flows predicted by the models were usually within about 5 to 10 percent of measured values. In future phases of the project, the models for attic/radiant barrier performance will be coupled with a whole-house model and further comparisons with experimental data will be made. Following this, the models will be utilized to provide an initial assessment of the energy savings potential of radiant barriers in various configurations and under various climatic conditions. 38 refs., 14 figs., 22 tabs.

Selective tungsten deposition in a batch cold wall CVD system

International Nuclear Information System (INIS)

Chow, R.; Kang, S.; Harshbarger, W.R.; Susoeff, M.

1987-01-01

Selective deposition of tungsten offers many advantages for VLSI technology. The process can be used as a planarization technique for multilevel interconnect technology, it can be used to fill contacts and to provide a barrier layer between Al and Si materials, and the selective W process might be used as a self-aligned technology to provide low resistance layers on source/drain and gate conductors. Recent publications have indicate that cold wall CVD systems provide advantages for development of selective W process. Genus has investigated selective W deposition processing, and we have developed a selective W deposition process for the Genus 8402 multifilm deposition system. This paper describes the Genus 8402 system and the selective W process developed in this reactor. To further develop selective W technology, Genus has signed an agreement with General Electric establishing a joint development program. As a part of this program, the authors characterized the selective W process for encroachment, Si consumption and degrees of selectivity on various dielectrics. The status of this development activity and process characterization is reviewed in this paper

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

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

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

Barriers to global health development: An international quantitative survey.

Directory of Open Access Journals (Sweden)

Bahr Weiss

Full Text Available Global health's goal of reducing low-and-middle-income country versus high-income country health disparities faces complex challenges. Although there have been discussions of barriers, there has not been a broad-based, quantitative survey of such barriers.432 global health professionals were invited via email to participate in an online survey, with 268 (62% participating. The survey assessed participants' (A demographic and global health background, (B perceptions regarding 66 barriers' seriousness, (C detailed ratings of barriers designated most serious, (D potential solutions.Thirty-four (of 66 barriers were seen as moderately or more serious, highlighting the widespread, significant challenges global health development faces. Perceived barrier seriousness differed significantly across domains: Resource Limitations mean = 2.47 (0-4 Likert scale, Priority Selection mean = 2.20, Corruption, Lack of Competence mean = 1.87, Social and Cultural Barriers mean = 1.68. Some system-level predictors showed significant but relatively limited relations. For instance, for Global Health Domain, HIV and Mental Health had higher levels of perceived Social and Cultural Barriers than other GH Domains. Individual-level global health experience predictors had small but significant effects, with seriousness of (a Corruption, Lack of Competence, and (b Priority Selection barriers positively correlated with respondents' level of LMIC-oriented (e.g., weeks/year spent in LMIC but Academic Global Health Achievement (e.g., number of global health publications negatively correlated with overall barrier seriousness.That comparatively few system-level predictors (e.g., Organization Type were significant suggests these barriers may be relatively fundamental at the system-level. Individual-level and system-level effects do have policy implications; e.g., Priority Selection barriers were among the most serious, yet effects on seriousness of how LMIC-oriented a professional

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.

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.

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.

Representing solute transport through the multi-barrier disposal system by simplified concepts

International Nuclear Information System (INIS)

Poteri, A.; Nordman, H.; Pulkkanen, V-M.; Kekaelaeinen, P.; Hautojaervi, A.

2012-02-01

The repository system chosen in Finland for spent nuclear fuel is composed of multiple successive transport barriers. If a waste canister is leaking, this multi-barrier system retards and limits the release rates of radionuclides into the biosphere. Analysis of radionuclide migration in the previous performance assessments has largely been based on numerical modelling of the repository system. The simplified analytical approach introduced here provides a tool to analyse the performance of the whole system using simplified representations of the individual transport barriers. This approach is based on the main characteristics of the individual barriers and on the generic nature of the coupling between successive barriers. In the case of underground repository the mass transfer between successive transport barriers is strongly restricted by the interfaces between barriers leading to well-mixed conditions in these barriers. The approach here simplifies the barrier system so that it can be described with a very simple compartment model, where each barrier is represented by a single, or in the case of buffer, by not more than two compartments. This system of compartments could be solved in analogy with a radioactive decay chain. The model of well mixed compartments lends itself to a very descriptive way to represent and analyse the barrier system because the relative efficiency of the different barriers in hindering transport of solutes can be parameterised by the solutes half-times in the corresponding compartments. In a real repository system there will also be a delay between the start of the inflow and the start of the outflow from the barrier. This delay can be important for the release rates of the short lived and sorbing radionuclides, and it was also included in the simplified representation of the barrier system. In a geological multi-barrier system, spreading of the outflowing release pulse is often governed by the typical behaviour of one transport barrier

Representing solute transport through the multi-barrier disposal system by simplified concepts

Energy Technology Data Exchange (ETDEWEB)

Poteri, A.; Nordman, H.; Pulkkanen, V-M. [VTT Technical Research Centre of Finland, Espoo (Finland); Kekaelaeinen, P. [Jyvaeskylae Univ. (Finland). Dept. pf Physics; Hautojaervi, A.

2012-02-15

The repository system chosen in Finland for spent nuclear fuel is composed of multiple successive transport barriers. If a waste canister is leaking, this multi-barrier system retards and limits the release rates of radionuclides into the biosphere. Analysis of radionuclide migration in the previous performance assessments has largely been based on numerical modelling of the repository system. The simplified analytical approach introduced here provides a tool to analyse the performance of the whole system using simplified representations of the individual transport barriers. This approach is based on the main characteristics of the individual barriers and on the generic nature of the coupling between successive barriers. In the case of underground repository the mass transfer between successive transport barriers is strongly restricted by the interfaces between barriers leading to well-mixed conditions in these barriers. The approach here simplifies the barrier system so that it can be described with a very simple compartment model, where each barrier is represented by a single, or in the case of buffer, by not more than two compartments. This system of compartments could be solved in analogy with a radioactive decay chain. The model of well mixed compartments lends itself to a very descriptive way to represent and analyse the barrier system because the relative efficiency of the different barriers in hindering transport of solutes can be parameterised by the solutes half-times in the corresponding compartments. In a real repository system there will also be a delay between the start of the inflow and the start of the outflow from the barrier. This delay can be important for the release rates of the short lived and sorbing radionuclides, and it was also included in the simplified representation of the barrier system. In a geological multi-barrier system, spreading of the outflowing release pulse is often governed by the typical behaviour of one transport barrier

Management-retrieval code system of fission barrier parameter sub-library

International Nuclear Information System (INIS)

Zhang Limin; Su Zongdi; Ge Zhigang

1995-01-01

The fission barrier parameter (FBP) library, which is a sub-library of Chinese Evaluated Nuclear Parameter library (CENPL), stores various popular used fission barrier parameters from different historical period, and could retrieve the required fission barrier parameters by using the management retrieval code system of the FBP sub-library. The function, feature and operation instruction of the code system are described briefly

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...

Engineered Barrier System: Physical and Chemical Environment Model

International Nuclear Information System (INIS)

Jolley, D. M.; Jarek, R.; Mariner, 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

Improvements in or relating to thermal barrier systems

International Nuclear Information System (INIS)

Birch, W.; Pearson, R.

1976-01-01

Reference is made to thermal barrier systems for the internal surface of gas cooled reactor prestressed concrete pressure vessels. Provision has to be made to anchor the thermal barrier system to a metal limit within the pressure vessel, and the object of the arrangement described is to provided a suitable attachment means. The thermal barrier may consist of a number of plates arranged in overlapped fashion or having flexible joint portions. A problem that arises concerns anchoring of the hot plates to the cold pressure vessel by a rigid attachment, and the design must be such as to ensure adequate bending and axial strength compatible with a minimum heat conduction area and allowable thermal stress. The arrangement must also allow easy installation. The arrangement described also provides for a 'fail-safe' structure. It comprises a metal stud with a hollow body; two or more helical channels are provided through the side walls of the body. The body portion expands or contracts to accommodate axial temperature gradient stress set up by the temperature difference between the pressure vessel and the thermal barrier. The space between the thermal barrier and the pressure vessel may contain solid insulating material. (U.K.)

Development of an Integrated Natural Barrier Database System for Site Evaluation of a Deep Geologic Repository in Korea - 13527

International Nuclear Information System (INIS)

Jung, Haeryong; Lee, Eunyong; Jeong, YiYeong; Lee, Jeong-Hwan

2013-01-01

Korea Radioactive-waste Management Corporation (KRMC) established in 2009 has started a new project to collect information on long-term stability of deep geological environments on the Korean Peninsula. The information has been built up in the integrated natural barrier database system available on web (www.deepgeodisposal.kr). The database system also includes socially and economically important information, such as land use, mining area, natural conservation area, population density, and industrial complex, because some of this information is used as exclusionary criteria during the site selection process for a deep geological repository for safe and secure containment and isolation of spent nuclear fuel and other long-lived radioactive waste in Korea. Although the official site selection process has not been started yet in Korea, current integrated natural barrier database system and socio-economic database is believed that the database system will be effectively utilized to narrow down the number of sites where future investigation is most promising in the site selection process for a deep geological repository and to enhance public acceptance by providing readily-available relevant scientific information on deep geological environments in Korea. (authors)

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

Engineered Barrier System: Physical and Chemical Environment Model

Energy Technology Data Exchange (ETDEWEB)

D. M. Jolley; R. Jarek; P. Mariner

2004-02-09

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.

Natural and sexual selection giveth and taketh away reproductive barriers: models of population divergence in guppies.

Science.gov (United States)

Labonne, Jacques; Hendry, Andrew P

2010-07-01

The standard predictions of ecological speciation might be nuanced by the interaction between natural and sexual selection. We investigated this hypothesis with an individual-based model tailored to the biology of guppies (Poecilia reticulata). We specifically modeled the situation where a high-predation population below a waterfall colonizes a low-predation population above a waterfall. Focusing on the evolution of male color, we confirm that divergent selection causes the appreciable evolution of male color within 20 generations. The rate and magnitude of this divergence were reduced when dispersal rates were high and when female choice did not differ between environments. Adaptive divergence was always coupled to the evolution of two reproductive barriers: viability selection against immigrants and hybrids. Different types of sexual selection, however, led to contrasting results for another potential reproductive barrier: mating success of immigrants. In some cases, the effects of natural and sexual selection offset each other, leading to no overall reproductive isolation despite strong adaptive divergence. Sexual selection acting through female choice can thus strongly modify the effects of divergent natural selection and thereby alter the standard predictions of ecological speciation. We also found that under no circumstances did divergent selection cause appreciable divergence in neutral genetic markers.

Down-regulation of selected Blood-brain Barrier Specific Genes from Capillaries to Bovine In Vitro Models

DEFF Research Database (Denmark)

Goldeman, Charlotte; Saaby, Lasse; Brodin, Birger

Cultures of primary bovine brain endothelial cells (BECs) grown, often together with astrocytes, on permeable supports in two-compartment culture systems are commonly used as an in vitro model of the blood-brain barrier (BBB). While trans-endothelial electrical resistance, restriction...... the in vivo gene expression of brain capillary endothelial cells. Primary bovine endothelial cells and rat astrocytes were cultured in different culture configurations and the mRNA expression of selected genes (vWF, Glut-1, P-gp, claudin-1,-5, occludin, JAM-1, LAT-1, SLC16A1, MRP-1,-4, BCRP, ZO-1, AP, TPA...

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

Overcoming energy efficiency barriers through systems approach—A conceptual framework

International Nuclear Information System (INIS)

Chai, Kah-Hin; Yeo, Catrina

2012-01-01

In this paper we propose a framework which categorizes energy efficiency barriers based on the stage at which the barriers exist. Barriers to energy efficiency have been widely studied but to our knowledge, except for a few studies, we found inadequate consideration for barrier–barrier interactions when proposing policy measures for improving energy efficiency. Leveraging systems thinking's power as a problem solver which identifies underlying structure that explains (similar) patterns of behavior in a variety of different situations, we attempted to identify patterns of barriers to adoption of energy efficiency measures in industrial companies. Inspired by systems thinking, the proposed framework has four stages, namely, Motivation, Capability, Implementation and Results, as well as a feedback loop. Using a case study, we show that following the four stages will lead to positive feedback for future energy efficiency implementations. The framework highlights the interconnected nature of the barriers and a need for policymakers to address these barriers in a holistic manner. We argue that the overall effectiveness of energy efficiency policies is only as strong as the weakest link in the four-stage framework. This differs from most prior research that addressed barriers in isolation, where a solution is proposed for each of the barriers without considering the relationship between the barriers. Our framework also offers a way to understand the roles and responsibilities of major stakeholders such as governments and energy service companies (ESCOs) in driving energy efficiency. This allows the assessment and identification of weak links in energy efficiency policies. - Highlights: ► We propose a systems approach to overcome energy efficiency barriers. ► Barriers are grouped into Motivation, Capability, Implementation and Results. ► Case study shows that there is a feedback loop from Results to Motivation. ► Current Results will affect future Motivation. �

Impact of vertical barriers on performance of pump-and-treat systems

International Nuclear Information System (INIS)

Russell, K.; Rabideau, A.

1997-01-01

Although aquifer remediation by Pump-and-treat (PAT) is widely practiced, it is generally implemented as an effective means of plume containment, rather than as an efficient means of contaminant mass removal. The use of slurry cutoff walls has been recognized as a means of improving the performance of PAT with respect to hydraulic control. As part of a study on the use of decision analysis in the design of aquifer remediation systems, the economic tradeoffs between capital costs and risk reduction were compared for several alternative PAT strategies. This work included an evaluation of the use of vertical barriers as components of PAT systems, using numerical experiments to examine the impacts of vertical barriers on PAT reliability. The results indicated that the use of vertical barriers in conjunction with PAT can significantly improve the simulated system performance, but that the magnitude of the predicted enhancement and cost-effectiveness of the barrier system are dependent on site characteristics, barrier placement, and modeling assumptions

Design studies on the engineered barrier system and on the in-situ experiments under the conditions of geological environment in Horonobe

International Nuclear Information System (INIS)

Kurihara, Yuji; Yui, Mikazu; Tanai, Kenji

2004-04-01

Following studies have been done in this papers in order to apply the technologies based on H12 report to the actual geological conditions of Horonobe underground research laboratory. 1) Reconsidering the process of repository design, the design process charts of a repository were presented. In the H12 report, the design process of the engineering barrier system was followed by the facility design process. In this paper, the both processes were placed in parallel position. 2) The relation between geological conditions and the performance of engineering barrier systems and the specifications of engineering barrier systems was arranged and the geological information needed for design of engineering barrier were selected. 3) The appropriate form of geological information as input-data for design were showed and the procedure for setting input-data was presented. 4) Based on the state of geological investigations at Horonobe, mechanical input-data were arranged for the design of the in-situ experiments on engineered barrier system at HORONOBE. 5) The stability of the hall for the in-situ experiments was studied by numerical analysis and the results indicated that there are difference in stability between the depth of 500 m and 570 m. (author)

Development of backfill material as an engineered barrier in the waste package system. Interim topical report

International Nuclear Information System (INIS)

Wheelwright, E.J.; Hodges, F.N.; Bray, L.A.; Westsik, J.H. Jr.; Lester, D.H.; Nakai, T.L.; Spaeth, M.E.; Stula, R.T.

1981-09-01

A backfill barrier, emplaced between the containerized waste and the host rock, can both protect the other engineered barriers and act as a primary barrier to the release of radionuclides from the waste package. Attributes that a backfill should provide in order to carry out its required function have been identified. Primary attributes are those that have a direct effect upon the release and transport of radionuclides from the waste package. Supportive attributes do not directly affect radionuclide release but are necessary to support the primary attributes. The primary attributes, in order of importance, are: minimize (retard or exclude) the migration of ground water between the host rock and the waste canister system; retard the migration of selected chemical species (corrosive species and radionuclides) in the ground water; control the Eh and pH of the ground water within the waste-package environment. The supportive attributes are: self-seal any cracks or discontinuities in the backfill or interfacing host geology; retain performance properties at all repository temperatures; retain peformance properties during and after receiving repository levels of gamma radiation; conduct heat from the canister system to the host geology; retain mechanical properties and provide resistance to applied mechanical forces; retain morphological stability and compatibility with structural barriers and with the host geology for required period of time. Screening and selection of candidate backfill materials has resulted in a preliminary list of materials for testing. Primary emphasis has been placed on sodium and calcium bentonites and zeolites used in conjunction with quartz sand or crushed host rock. Preliminary laboratory studies have concentrated on permeability, sorption, swelling pressure, and compaction properties of candidate backfill materials

Barriers to Electronic Health Record Adoption: a Systematic Literature Review.

Science.gov (United States)

Kruse, Clemens Scott; Kristof, Caitlin; Jones, Beau; Mitchell, Erica; Martinez, Angelica

2016-12-01

Federal efforts and local initiatives to increase adoption and use of electronic health records (EHRs) continue, particularly since the enactment of the Health Information Technology for Economic and Clinical Health (HITECH) Act. Roughly one in four hospitals not adopted even a basic EHR system. A review of the barriers may help in understanding the factors deterring certain healthcare organizations from implementation. We wanted to assemble an updated and comprehensive list of adoption barriers of EHR systems in the United States. Authors searched CINAHL, MEDLINE, and Google Scholar, and accepted only articles relevant to our primary objective. Reviewers independently assessed the works highlighted by our search and selected several for review. Through multiple consensus meetings, authors tapered articles to a final selection most germane to the topic (n = 27). Each article was thoroughly examined by multiple authors in order to achieve greater validity. Authors identified 39 barriers to EHR adoption within the literature selected for the review. These barriers appeared 125 times in the literature; the most frequently mentioned barriers were regarding cost, technical concerns, technical support, and resistance to change. Despite federal and local incentives, the initial cost of adopting an EHR is a common existing barrier. The other most commonly mentioned barriers include technical support, technical concerns, and maintenance/ongoing costs. Policy makers should consider incentives that continue to reduce implementation cost, possibly aimed more directly at organizations that are known to have lower adoption rates, such as small hospitals in rural areas.

Engineered barrier systems (EBS): design requirements and constraints

International Nuclear Information System (INIS)

2004-01-01

A joint NEA-EC workshop entitled 'Engineered Barrier Systems: Design Requirements and Constraints' was organised in Turku, Finland on 26-29 August 2003 and hosted by Posiva Oy. The main objectives of the workshop were to promote interaction and collaboration among experts responsible for engineering design and safety assessment in order to develop a greater understanding of how to achieve the integration needed for the successful design of engineered barrier systems, and to clarify the role that an EBS can play in the overall safety case for a repository. These proceedings present the outcomes of this workshop. (author)

A multi-attribute decision model for portfolio selection aiming to replace technologies in industrial motor systems

International Nuclear Information System (INIS)

Vanderley Herrero Sola, Antonio; Mota, Caroline Maria de Miranda

2012-01-01

Highlights: ► We propose a multicriteria decision model for technology replacement. ► We prioritize induction motors in order to improve the energy efficiency. ► The best portfolio of options is selected based on decision maker’s utilities. ► The model contribute to surpass some organizational barriers. - Abstract: The energy efficient technologies offered by the market are in constant evolution, but their insertion in the productive sector comes up against organizational barriers, which obstruct decision making in firms. This paper proposes a multicriteria decision model in order to replace technologies in industrial energy systems, regarding organizational barriers for energy efficiency. The proposed model is applied in industrial motor systems, using Multi-Attribute Utility Theory (MAUT), in order to select the best portfolio of options based on the decision maker’s utilities. Portfolios of options from the prioritized set of motors compiled by the operational area of the studied industry are analyzed, including diverse suppliers and different classes of motors. The results show that it is essential to structure the proposed model in two steps, beginning with the operational level, to ensure that important technologies for the production system are prioritized, thus preserving the interests of the organization and improving the efficiency of industrial energy systems.

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

Load management for refrigeration systems: Potentials and barriers

Energy Technology Data Exchange (ETDEWEB)

Grein, Arne, E-mail: a.grein@tu-berlin.de [University of Technology Berlin, Institute for Energy Technology, Department of Energy Systems, Einsteinufer 25 (TA8), 10587 Berlin (Germany); Pehnt, Martin [Institute for Energy and Environmental Research Heidelberg (ifeu), Wilckensstr. 3, 69120 Heidelberg (Germany)

2011-09-15

As a strategy to deal with the increasing intermittent input of renewable energy sources in Germany, the adaptation of power consumption is complementary to power-plant regulation, grid expansion and physical energy storage. One demand sector that promises strong returns for load management efforts is cooling and refrigeration. In these processes, thermal inertia provides a temporal buffer for shifting and adjusting the power consumption of cooling systems. We have conducted an empirical investigation to obtain a detailed and time-resolved bottom-up analysis of load management for refrigeration systems in the city of Mannheim, Germany. We have extrapolated our results to general conditions in Germany. Several barriers inhibit the rapid adoption of load management strategies for cooling systems, including informational barriers, strict compliance with legal cooling requirements, liability issues, lack of technical experience, an inadequate rate of return and organizational barriers. Small commercial applications of refrigeration in the food-retailing and cold storage in hotels and restaurants are particularly promising starting points for intelligent load management. When our results are applied to Germany, suitable sectors for load management have theoretical and achievable potential values of 4.2 and 2.8 GW, respectively, amounting to about 4-6% of the maximum power demand in Germany. - Highlights: > Potential and barriers for implementation of load shifting for refrigeration. > Empirical investigation for time-resolved bottom-up analysis in Mannheim, Germany. > Suitable sectors and further recommendations for introducing load management.> Extrapolation of results from local to national level.

Load management for refrigeration systems: Potentials and barriers

International Nuclear Information System (INIS)

Grein, Arne; Pehnt, Martin

2011-01-01

As a strategy to deal with the increasing intermittent input of renewable energy sources in Germany, the adaptation of power consumption is complementary to power-plant regulation, grid expansion and physical energy storage. One demand sector that promises strong returns for load management efforts is cooling and refrigeration. In these processes, thermal inertia provides a temporal buffer for shifting and adjusting the power consumption of cooling systems. We have conducted an empirical investigation to obtain a detailed and time-resolved bottom-up analysis of load management for refrigeration systems in the city of Mannheim, Germany. We have extrapolated our results to general conditions in Germany. Several barriers inhibit the rapid adoption of load management strategies for cooling systems, including informational barriers, strict compliance with legal cooling requirements, liability issues, lack of technical experience, an inadequate rate of return and organizational barriers. Small commercial applications of refrigeration in the food-retailing and cold storage in hotels and restaurants are particularly promising starting points for intelligent load management. When our results are applied to Germany, suitable sectors for load management have theoretical and achievable potential values of 4.2 and 2.8 GW, respectively, amounting to about 4-6% of the maximum power demand in Germany. - Highlights: → Potential and barriers for implementation of load shifting for refrigeration. → Empirical investigation for time-resolved bottom-up analysis in Mannheim, Germany. → Suitable sectors and further recommendations for introducing load management.→ Extrapolation of results from local to national level.

Development of the Canadian used fuel repository engineered barrier system

Energy Technology Data Exchange (ETDEWEB)

Hatton, C., E-mail: chatton@nwmo.ca [Nuclear Waste Management Organization, Toronto, ON (Canada)

2015-07-01

The Nuclear Waste Management Organization (NWMO) is responsible for the implementation of Adaptive Phased Management (APM), the federally-approved plan for the safe long-term management of Canada's used nuclear fuel. Under the APM plan, used nuclear fuel will ultimately be placed within a deep geological repository in a suitable rock formation. In implementing APM, the NWMO is committed to ensure consistency with international best practices in the development of its repository system, including any advances in technology. In 2012, the NWMO undertook an optimization study to look at both the design and manufacture of its engineered barriers. This study looked at current technologies for the design and manufacture of used fuel containers, placement technologies, repository design, and buffer and sealing systems, while taking into consideration the state of the art worldwide in repository design and acceptance. The result of that study is the current Canadian engineered barrier system, consisting of a 2.7 tonne used fuel container with a carbon-steel core, copper-coated surface and welded spherical heads. The used fuel container is encapsulated in a bentonite buffer box at the surface and then transferred underground. Once underground, the used fuel is placed into a repository room which is cut into the rock using traditional drill-and-blast technologies. This paper explains the logic for the selection of the container and sealing system design and the development of innovative technologies for their manufacture including the use of laser welding, cold spray and pulsed-electrodeposition copper coating for the manufacture of the used fuel container, isostatic presses for the production of the one-piece bentonite blocks, and slip-skid technologies for placement into the repository. (author)

Development of the Canadian used fuel repository engineered barrier system

International Nuclear Information System (INIS)

Hatton, C.

2015-01-01

The Nuclear Waste Management Organization (NWMO) is responsible for the implementation of Adaptive Phased Management (APM), the federally-approved plan for the safe long-term management of Canada's used nuclear fuel. Under the APM plan, used nuclear fuel will ultimately be placed within a deep geological repository in a suitable rock formation. In implementing APM, the NWMO is committed to ensure consistency with international best practices in the development of its repository system, including any advances in technology. In 2012, the NWMO undertook an optimization study to look at both the design and manufacture of its engineered barriers. This study looked at current technologies for the design and manufacture of used fuel containers, placement technologies, repository design, and buffer and sealing systems, while taking into consideration the state of the art worldwide in repository design and acceptance. The result of that study is the current Canadian engineered barrier system, consisting of a 2.7 tonne used fuel container with a carbon-steel core, copper-coated surface and welded spherical heads. The used fuel container is encapsulated in a bentonite buffer box at the surface and then transferred underground. Once underground, the used fuel is placed into a repository room which is cut into the rock using traditional drill-and-blast technologies. This paper explains the logic for the selection of the container and sealing system design and the development of innovative technologies for their manufacture including the use of laser welding, cold spray and pulsed-electrodeposition copper coating for the manufacture of the used fuel container, isostatic presses for the production of the one-piece bentonite blocks, and slip-skid technologies for placement into the repository. (author)

Workplace barriers encountered by employed persons with systemic sclerosis.

Science.gov (United States)

Poole, Janet L; Anwar, Sahar; Mendelson, Cindy; Allaire, Saralynn

2016-01-01

Systemic sclerosis (SSc) is an auto-immune connective tissue disease characterized by fibrosis of skin, blood vessels, and internal organs that results in significant disability. To identify the work barriers faced by people with systemic sclerosis (SSc) in maintaining employment. Thirty-six people with SSc who were working more than 8 hours per week completed the Work Experience Survey, which contains lists of potential work barriers, including the ability to travel to and from work; get around at work; perform essential job functions, including physical, cognitive, and task-related activities; work with others; and manage work conditions. Thirty-three participants completed and returned the questionnaires, most of whom were female, and working full time and in professional careers. Principal disease symptoms included fatigue, Raynaud's phenomenon, esophageal involvement, and leg or hand/wrist pain. All participants reported some barriers with a mean of 18 barriers per participant. At least three quarters of participants cited outside temperature (82%), cold temperatures inside the workplace (76%), and household work (76%), as barriers. The next most common barriers were using both hands (64%), arranging and taking part in social activities (64%), being able to provide self-care (61%) and working 8 hours (58%). Participants reported a wide range of barriers, from cold temperatures, to physical job, fatigue related, and non-workplace demands, in maintaining the worker role. The barriers reflect the disease symptoms they reported. Identifying workplace barriers facilitates the creation of job accommodations or adaptations that will allow people with SSc to continue working.

Selection of design parameters of diffusion barrier in a passive 222Rn sampler based on activated charcoal adsorption

International Nuclear Information System (INIS)

Wei Suxia

1992-01-01

A method concerning selection of design parameters of diffusion barrier in a passive 222 Rn sampler based on activated charcoal adsorption. The proper parameter value of diffusion barrier is obtained by means of linearization of 222 Rn adsorption versus the exposure time. Thus, the influence of temperature on measured results may be greatly decreased, and higher sensitivity of the detector may be maintained

Behavior of nine selected emerging trace organic contaminants in an artificial recharge system supplemented with a reactive barrier.

Science.gov (United States)

Valhondo, Cristina; Carrera, Jesús; Ayora, Carlos; Barbieri, Manuela; Nödler, Karsten; Licha, Tobias; Huerta, Maria

2014-10-01

Artificial recharge improves several water quality parameters, but has only minor effects on recalcitrant pollutants. To improve the removal of these pollutants, we added a reactive barrier at the bottom of an infiltration basin. This barrier contained aquifer sand, vegetable compost, and clay and was covered with iron oxide dust. The goal of the compost was to sorb neutral compounds and release dissolved organic carbon. The release of dissolved organic carbon should generate a broad range of redox conditions to promote the transformation of emerging trace organic contaminants (EOCs). Iron oxides and clay increase the range of sorption site types. In the present study, we examined the effectiveness of this barrier by analyzing the fate of nine EOCs. Water quality was monitored before and after constructing the reactive barrier. Installation of the reactive barrier led to nitrate-, iron-, and manganese-reducing conditions in the unsaturated zone below the basin and within the first few meters of the saturated zone. Thus, the behavior of most EOCs changed after installing the reactive barrier. The reactive barrier enhanced the removal of some EOCs, either markedly (sulfamethoxazole, caffeine, benzoylecgonine) or slightly (trimethoprim) and decreased the removal rates of compounds that are easily degradable under aerobic conditions (ibuprofen, paracetamol). The barrier had no remarkable effect on 1H-benzotriazole and tolyltriazole.

Emergent Behavior of Coupled Barrier Island - Resort Systems

Science.gov (United States)

McNamara, D. E.; Werner, B. T.

2004-12-01

Barrier islands are attractive sites for resorts. Natural barrier islands experience beach erosion and island overwash during storms, beach accretion and dune building during inter-storm periods, and migration up the continental shelf as sea level rises. Beach replenishment, artificial dune building, seawalls, jetties and groins have been somewhat effective in protecting resorts against erosion and overwash during storms, but it is unknown how the coupled system will respond to long-term sea level rise. We investigate coupled barrier island - resort systems using an agent-based model with three components: natural barrier islands divided into a series of alongshore cells; resorts controlled by markets for tourism and hotel purchases; and coupling via storm damage to resorts and resort protection by government agents. Modeled barrier islands change by beach erosion, island overwash and inlet cutting during storms, and beach accretion, tidal delta growth and dune and vegetation growth between storms. In the resort hotel market, developer agents build hotels and hotel owning agents purchase them using predictions of future revenue and property appreciation, with the goal of maximizing discounted utility. In the tourism market, hotel owning agents set room rental prices to maximize profit and tourist agents choose vacation destinations maximizing a utility based on beach width, price and word-of-mouth. Government agents build seawalls, groins and jetties, and widen the beach and build up dunes by adding sand to protect resorts from storms, enhance beach quality, and maximize resort revenue. Results indicate that barrier islands and resorts evolve in a coupled manner to resort size saturation, with resorts protected against small-to-intermediate-scale storms under fairly stable sea level. Under extended, rapidly rising sea level, protection measures enhance the effect of large storms, leading to emergent behavior in the form of limit cycles or barrier submergence

Chemisorption on size-selected metal clusters: activation barriers and chemical reactions for deuterium and aluminum cluster ions

International Nuclear Information System (INIS)

Jarrold, M.F.; Bower, J.E.

1988-01-01

The authors describe a new approach to investigating chemisorption on size-selected metal clusters. This approach involves investigating the collision-energy dependence of chemisorption using low-energy ion beam techniques. The method provides a direct measure of the activation barrier for chemisorption and in some cases an estimate of the desorption energy as well. They describe the application of this technique to chemisorption of deuterium on size-selected aluminum clusters. The activation barriers increase with cluster size (from a little over 1 eV for Al 10 + to around 2 eV for Al 27 + ) and show significant odd-even oscillations. The activation barriers for the clusters with an odd number of atoms are larger than those for the even-numbered clusters. In addition to chemisorption of deuterium onto the clusters, chemical reactions were observed, often resulting in cluster fragmentation. The main products observed were Al/sub n-1/D + , Al/sub n-2/ + , and Al + for clusters with n + and Al/sub n-1/D + for the larger clusters

Reducing Barriers To The Use of High-Efficiency Lighting Systems

Energy Technology Data Exchange (ETDEWEB)

Peter Morante

2005-12-31

With funding from the U.S. Department of Energy (DOE), the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute completed the four-year research project, Reducing Barriers to the Use of High-Efficiency Lighting Systems. The initial objectives were: (1) identifying barriers to widespread penetration of lighting controls in commercial/industrial (C/I) applications that employ fluorescent lamp technologies, and (2) making recommendations to overcome these barriers. The addition of a fourth year expanded the original project objectives to include an examination of the impact on fluorescent lamps from dimming utilizing different lamp electrode heating and dimming ratios. The scope of the project was narrowed to identify barriers to the penetration of lighting controls into commercial-industrial (C/I) applications that employ fluorescent lamp technologies, and to recommend means for overcoming these barriers. Working with lighting manufacturers, specifiers, and installers, the project identified technological and marketing barriers to the widespread use of lighting controls, specifically automatic-off controls, occupancy sensors, photosensors, dimming systems, communication protocols and load-shedding ballasts. The primary barriers identified include cost effectiveness of lighting controls to the building owner, lack of standard communication protocols to allow different part of the control system to communicate effectively, and installation and commissioning issues. Overcoming the identified barriers requires lighting control products on the market to achieve three main goals: (1) Achieve sufficient functionality to meet the key requirements of their main market. (2) Allow significant cost reduction compared to current market standard systems. Cost should consider: hardware capital cost including wiring, design time required by the specifier and the control system manufacturer, installation time required by the electrician, and commissioning time and

[The blood-brain barrier and drug delivery in the central nervous system].

Science.gov (United States)

Loch-Neckel, Gecioni; Koepp, Janice

2010-08-01

To provide an updated view of the difficulties due to barriers and strategies used to allow the release of drugs in the central nervous system. The difficulty for the treatment of many diseases of the central nervous system, through the use of intra-venous drugs, is due to the presence of barriers that prevent the release of the same: the blood-brain barrier, blood-cerebro-spinal fluid barrier and the blood-arachnoid barrier. The blood-brain barrier is the main barrier for the transport of drugs in the brain that also acts as a immunologic and metabolic barrier. The endothelial cells of the blood-brain barrier are connected to a junction complex through the interaction of transmembrane proteins that protrude from de inside to the outside, forming a connection between the endothelial cells. The transport of substances to the brain depends on the mechanisms of transport present in the barrier and the diffusion of these compounds also depends on the physicochemical characteristics of the molecule. Some diseases alter the permeability of the blood-brain barrier and thus the passage of drugs. Strategies such as the use of methods for drug delivery in the brain have been investigated. Further details regarding the mechanisms of transport across the blood-brain barrier and the changes in neuropathology would provide important information about the etiology of diseases and lead to better therapeutic strategies.

The role of plants on isolation barrier systems

International Nuclear Information System (INIS)

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

1994-11-01

Surface barriers are used to isolate buried wastes from the environment. Most have been built for short-term isolation. The need to isolate radioactive wastes from the environment requires that the functional integrity of a barrier be maintained for thousands of years. Barrier function strongly depends on vegetation. Plants reduce wind and water erosion and minimize drainage, but may transport contaminants if roots extend into buried wastes. Our review of the function of plants on surface barriers focuses on the role of plants across mesic to arid environments and gives special consideration to studies done at Hanford. The Hanford Barrier Development Program was created to design and test an earthen cover system to inhibit water infiltration, plant and animal intrusion, and wind and water erosion, while isolating buried wastes for at least 1000 years. Studies at the Hanford have shown that plants will significantly interact with the barrier. Plants transpire soil water back into the atmosphere. Deep-rooted perennials best recycle water; soil water may drain through the root zone of shallow-rooted annuals. Lysimeter studies indicate that a surface layer of fine soil with deep-rooted plants precludes drainage even with three times normal precipitation. The presence of vegetation greatly reduces water and wind erosion, but deep-rooted plants pose a threat of biointrusion and contaminant transport. The Hanford barrier includes a buried rock layer and asphalt layer to prevent biointrusion

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.

Disposal systems evaluations and tool development : Engineered Barrier System (EBS) evaluation.

Energy Technology Data Exchange (ETDEWEB)

Rutqvist, Jonny (LBNL); Liu, Hui-Hai (LBNL); Steefel, Carl I. (LBNL); Serrano de Caro, M. A. (LLNL); Caporuscio, Florie Andre (LANL); Birkholzer, Jens T. (LBNL); Blink, James A. (LLNL); Sutton, Mark A. (LLNL); Xu, Hongwu (LANL); Buscheck, Thomas A. (LLNL); Levy, Schon S. (LANL); Tsang, Chin-Fu (LBNL); Sonnenthal, Eric (LBNL); Halsey, William G. (LLNL); Jove-Colon, Carlos F.; Wolery, Thomas J. (LLNL)

2011-01-01

Key components of the nuclear fuel cycle are short-term storage and long-term disposal of nuclear waste. The latter encompasses the immobilization of used nuclear fuel (UNF) and radioactive waste streams generated by various phases of the nuclear fuel cycle, and the safe and permanent disposition of these waste forms in geological repository environments. The engineered barrier system (EBS) plays a very important role in the long-term isolation of nuclear waste in geological repository environments. EBS concepts and their interactions with the natural barrier are inherently important to the long-term performance assessment of the safety case where nuclear waste disposition needs to be evaluated for time periods of up to one million years. Making the safety case needed in the decision-making process for the recommendation and the eventual embracement of a disposal system concept requires a multi-faceted integration of knowledge and evidence-gathering to demonstrate the required confidence level in a deep geological disposal site and to evaluate long-term repository performance. The focus of this report is the following: (1) Evaluation of EBS in long-term disposal systems in deep geologic environments with emphasis on the multi-barrier concept; (2) Evaluation of key parameters in the characterization of EBS performance; (3) Identification of key knowledge gaps and uncertainties; and (4) Evaluation of tools and modeling approaches for EBS processes and performance. The above topics will be evaluated through the analysis of the following: (1) Overview of EBS concepts for various NW disposal systems; (2) Natural and man-made analogs, room chemistry, hydrochemistry of deep subsurface environments, and EBS material stability in near-field environments; (3) Reactive Transport and Coupled Thermal-Hydrological-Mechanical-Chemical (THMC) processes in EBS; and (4) Thermal analysis toolkit, metallic barrier degradation mode survey, and development of a Disposal Systems

Disposal systems evaluations and tool development: Engineered Barrier System (EBS) evaluation

International Nuclear Information System (INIS)

Rutqvist, Jonny; Liu, Hui-Hai; Steefel, Carl I.; Serrano de Caro, M.A.; Caporuscio, Florie Andre; Birkholzer, Jens T.; Blink, James A.; Sutton, Mark A.; Xu, Hongwu; Buscheck, Thomas A.; Levy, Schon S.; Tsang, Chin-Fu; Sonnenthal, Eric; Halsey, William G.; Jove-Colon, Carlos F.; Wolery, Thomas J.

2011-01-01

Key components of the nuclear fuel cycle are short-term storage and long-term disposal of nuclear waste. The latter encompasses the immobilization of used nuclear fuel (UNF) and radioactive waste streams generated by various phases of the nuclear fuel cycle, and the safe and permanent disposition of these waste forms in geological repository environments. The engineered barrier system (EBS) plays a very important role in the long-term isolation of nuclear waste in geological repository environments. EBS concepts and their interactions with the natural barrier are inherently important to the long-term performance assessment of the safety case where nuclear waste disposition needs to be evaluated for time periods of up to one million years. Making the safety case needed in the decision-making process for the recommendation and the eventual embracement of a disposal system concept requires a multi-faceted integration of knowledge and evidence-gathering to demonstrate the required confidence level in a deep geological disposal site and to evaluate long-term repository performance. The focus of this report is the following: (1) Evaluation of EBS in long-term disposal systems in deep geologic environments with emphasis on the multi-barrier concept; (2) Evaluation of key parameters in the characterization of EBS performance; (3) Identification of key knowledge gaps and uncertainties; and (4) Evaluation of tools and modeling approaches for EBS processes and performance. The above topics will be evaluated through the analysis of the following: (1) Overview of EBS concepts for various NW disposal systems; (2) Natural and man-made analogs, room chemistry, hydrochemistry of deep subsurface environments, and EBS material stability in near-field environments; (3) Reactive Transport and Coupled Thermal-Hydrological-Mechanical-Chemical (THMC) processes in EBS; and (4) Thermal analysis toolkit, metallic barrier degradation mode survey, and development of a Disposal Systems

The mechanisms of neurotoxicity and the selective vulnerability of nervous system sites.

Science.gov (United States)

Maurer, Laura L; Philbert, Martin A

2015-01-01

The spatial heterogeneity of the structure, function, and cellular composition of the nervous system confers extraordinary complexity and a multiplicity of mechanisms of chemical neurotoxicity. Because of its relatively high metabolic demands and functional dependence on postmitotic neurons, the nervous system is vulnerable to a variety of xenobiotics that affect essential homeostatic mechanisms that support function. Despite protection from the neuroglia and blood-brain barrier, the central nervous system is prone to attack from lipophilic toxicants and those that hijack endogenous transport, receptor, metabolic, and other biochemical systems. The inherent predilection of chemicals for highly conserved biochemical systems confers selective vulnerability of the nervous system to neurotoxicants. This chapter discusses selective vulnerability of the nervous system in the context of neuron-specific decrements (axonopathy, myelinopathy, disruption of neurotransmission), and the degree to which neuronal damage is facilitated or ameliorated by surrounding nonneural cells in both the central and peripheral nervous systems. © 2015 Elsevier B.V. All rights reserved.

Prediction of Placental Barrier Permeability: A Model Based on Partial Least Squares Variable Selection Procedure

Directory of Open Access Journals (Sweden)

Yong-Hong Zhang

2015-05-01

Full Text Available Assessing the human placental barrier permeability of drugs is very important to guarantee drug safety during pregnancy. Quantitative structure–activity relationship (QSAR method was used as an effective assessing tool for the placental transfer study of drugs, while in vitro human placental perfusion is the most widely used method. In this study, the partial least squares (PLS variable selection and modeling procedure was used to pick out optimal descriptors from a pool of 620 descriptors of 65 compounds and to simultaneously develop a QSAR model between the descriptors and the placental barrier permeability expressed by the clearance indices (CI. The model was subjected to internal validation by cross-validation and y-randomization and to external validation by predicting CI values of 19 compounds. It was shown that the model developed is robust and has a good predictive potential (r2 = 0.9064, RMSE = 0.09, q2 = 0.7323, rp2 = 0.7656, RMSP = 0.14. The mechanistic interpretation of the final model was given by the high variable importance in projection values of descriptors. Using PLS procedure, we can rapidly and effectively select optimal descriptors and thus construct a model with good stability and predictability. This analysis can provide an effective tool for the high-throughput screening of the placental barrier permeability of drugs.

DTR, Taut Wire System: An alarm barrier with experience

International Nuclear Information System (INIS)

Kraft, A.J.

1986-01-01

The Taut Wire Fence Alarm System concept was developed and introduced more that fifteen years ago in Israel. A sudden expansion of the nations's border lines, the difficulty to monitor intrusions along those elongated lines and the need for timely as well as accurate armed response to an intrusion attempt dictated the need for an alarming barrier. Traditionally, protection of perimeters was accomplished by the installation of a fence or other type obstacles (man made or natural) and surveillance by manned patrols, fixed observation posts, and/or electronic devices. Defense planners recognized therefore the need for an alarming barrier. A concentrated effort by scientists solved the problem by developing the first Taut Wire Fence Alarm System in a configuration of an alarm barrier. The system was specified to have an extremely low false alarm rate (FAR/NAR), high probability of detection, the capability to follow various terrains, operability in a wide range of environmental conditions, a capability to delay an intruder, ease of installation by unskilled labor, and low maintenance requirements. The authors try here to explain the various constraints and considerations given during the design stages of the Taut Wire Alarm System so as to bring the present magnitude of users to a better understanding of the system's operation

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.

The Effects of information barrier requirements on the trilateral initiative attribute measurement system (AVNG)

International Nuclear Information System (INIS)

MacArthur, D.W.; Langner, D.C.; Whiteson, R.; Wolford, J.K.

2001-01-01

Although the detection techniques used for measuring classified materials are very similar to those used in unclassified measurements, the surrounding packaging is generally very different. If iZ classified item is to be measured, an information barrier is required to protect any classified data acquired. This information barrier must protect the classified information while giving the inspector confidence that the unclassified outputs accurately reflect the classified inputs, Both information barrier and authentication considerations must be considered during all phases of system design and fabrication. One example of such a measurement system is the attribute measurement system (termed the AVNG) designed for the: Trilateral Initiative. We will discuss the integration of information barrier components into this system as well as the effects of an information barrier (including authentication) concerns on the implementation of the detector systems.

Chasing boundaries and cascade effects in a coupled barrier-marsh-lagoon system

Science.gov (United States)

Lorenzo-Trueba, Jorge; Mariotti, Giulio

2017-08-01

The long-term dynamic evolution of an idealized barrier-marsh-lagoon system experiencing sea-level rise is studied by coupling two existing numerical models. The barrier model accounts for the interaction between shoreface dynamics and overwash flux, which allows the occurrence of barrier drowning. The marsh-lagoon model includes both a backbarrier marsh and an interior marsh, and accounts for the modification of the wave regime associated with changes in lagoon width and depth. Overwash, the key process that connects the barrier shoreface with the marsh-lagoon ecosystems, is formulated to account for the role of the backbarrier marsh. Model results show that a number of factors that are not typically associated with the dynamics of coastal barriers can enhance the rate of overwash-driven landward migration by increasing backbarrier accommodation space. For instance, lagoon deepening could be triggered by marsh edge retreat and consequent export of fine sediment via tidal dispersion, as well as by an expansion of inland marshes and consequent increase in accommodation space to be filled in with sediment. A deeper lagoon results in a larger fraction of sediment overwash being subaqueous, which coupled with a slow shoreface response sending sediment onshore can trigger barrier drowning. We therefore conclude that the supply of fine sediments to the back-barrier and the dynamics of both the interior and backbarrier marsh can be essential for maintaining the barrier system under elevated rates of sea-level rise. Our results highlight the importance of considering barriers and their associated backbarriers as part of an integrated system in which sediment is exchanged.

Analysis of Barriers against Wheat Farmers' Participation in the Formation of Water Users Association: the Case of Dez Irrigation System

Directory of Open Access Journals (Sweden)

ali pazhuhan

2016-11-01

The present study was aimed at analyzing the barriers against wheat farmers' participation in the formation of water users association within the framework of a descriptive survey. The sample of this study included 375 wheat farmers in Dez irrigation system who were selected through random cluster sampling and were studied through a questionnaire. The reliability index of this questionnaire was estimated to be 0.89. The content validity of the questionnaire was confirmed by the experts and scholars in the field. After the participants filled the questionnaires and the data were collected, the SPSS software package was used to analyze the data. In addition, the results of factor analysis related to the items of barriers led to the extraction of four barriers. These barriers, in order of importance, include the lack of proper infrastructures and economic facilities, social barriers, inadequate structural characteristics and lack of risk-taking, local organizations and lack of attention to extension activities that explain 60.78 percent of the variance of all the barriers.

Hydraulic performance of permeable barriers for in situ treatment of contaminated groundwater

International Nuclear Information System (INIS)

Smyth, D.J.A.; Shikaze, S.G.; Cherry, J.A.

1997-01-01

The passive interception and in situ treatment of dissolved contaminants in groundwater by permeable reactive barriers has recently gained favor at an increasing number of sites as an alternative to conventional approaches to groundwater remediation such as the pump-and-treat method. Permeable reactive barriers have two essential functions. The first is that the barriers must be installed in a position such that all of the plume passes through the reactive system. The second function is to achieve acceptable treatment of the contamination by physical, chemical or biological means within or downgradient of the barrier. In this paper, issues associated with the hydraulic performance of permeable reaction barriers are evaluated using a three-dimensional groundwater flow model. The efficiency of plume capture by permeable wall and funnel-and-gate systems is examined for some generic and for site-specific hydrogeologic systems. The results have important implications to decisions pertaining to the selection, design and installation of permeable reactive barrier systems

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

Improving safety culture in hospitals: Facilitators and barriers to implementation of Systemic Falls Investigative Method (SFIM).

Science.gov (United States)

Zecevic, Aleksandra A; Li, Alvin Ho-Ting; Ngo, Charity; Halligan, Michelle; Kothari, Anita

2017-06-01

The purpose of this study was to assess the facilitators and barriers to implementation of the Systemic Falls Investigative Method (SFIM) on selected hospital units. A cross-sectional explanatory mixed methods design was used to converge results from a standardized safety culture survey with themes that emerged from interviews and focus groups. Findings were organized by six elements of the Ottawa Model of Research Use framework. A geriatric rehabilitation unit of an acute care hospital and a neurological unit of a rehabilitation hospital were selected purposefully due to the high frequency of falls. Hospital staff who took part in: surveys (n = 39), interviews (n = 10) and focus groups (n = 12), and 38 people who were interviewed during falls investigations: fallers, family, unit staff and hospital management. Implementation of the SFIM to investigate fall occurrences. Percent of positive responses on the Modified Stanford Patient Safety Culture Survey Instrument converged with qualitative themes on facilitators and barriers for intervention implementation. Both hospital units had an overall poor safety culture which hindered intervention implementation. Facilitators were hospital accreditation, strong emphasis on patient safety, infrastructure and dedicated champions. Barriers included heavy workloads, lack of time, lack of resources and poor communication. Successful implementation of SFIM requires regulatory and organizational support, committed frontline staff and allocation of resources to identify active causes and latent contributing factors to falls. System-wide adjustments show promise for promotion of safety culture in hospitals where falls happen regularly. © The Author 2017. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Fusion and particle transfer around the Coulomb-Barrier in intermediate systems

International Nuclear Information System (INIS)

Pascholati, P.R.

1989-01-01

The most important characteristics of fusion reactions below and around the Coulomb-barrier are summarized. Experimental fusion cross sections for typical systems are discussed and compared with current formulae obtained from semi-classical and quantum tunneling approaches. The influence of nucleons transfer in the enhancement of the fusion cross section below the Coulomb-barrier is also shown. Sub-barrier fusion cross sections for the systems 35,37 Cl + 58,64 Ni and 33 S + 90,91,92 Zr, and near-barrier cross sections of all important transfer channels have been measured using the XTU-TANDEM at Legnaro, Italy. In 35,37 Cl + 58,64 Ni systems, the motivation further investigated was the influence of the valence proton in the enhancement of the sub-barrier fusion cross section. The data are discussed in comparison with the similar data of 34,36 S + 58,64 Ni with the aim of revealing the influence of coupled proton transfer channels. Calculations were performed using the simplified coupled channel code CCFUS including ''pick-up'' of one and two neutrons and ''stripping'' of two neutrons channels. Signatures of positive Q-values transfer channels coupled to fusion were clearly identified. For the 33 S + 90,91,92 Zr systems taking into account the coupling effects between transfer and fusion and using the semi-classical approach, transfer form-factors were extracted and succesfully employed to described the isotopic effects in fusion enhancement. (Author) [es

Blood-brain barrier-on-a-chip: Microphysiological systems that capture the complexity of the blood-central nervous system interface.

Science.gov (United States)

Phan, Duc Tt; Bender, R Hugh F; Andrejecsk, Jillian W; Sobrino, Agua; Hachey, Stephanie J; George, Steven C; Hughes, Christopher Cw

2017-11-01

The blood-brain barrier is a dynamic and highly organized structure that strictly regulates the molecules allowed to cross the brain vasculature into the central nervous system. The blood-brain barrier pathology has been associated with a number of central nervous system diseases, including vascular malformations, stroke/vascular dementia, Alzheimer's disease, multiple sclerosis, and various neurological tumors including glioblastoma multiforme. There is a compelling need for representative models of this critical interface. Current research relies heavily on animal models (mostly mice) or on two-dimensional (2D) in vitro models, neither of which fully capture the complexities of the human blood-brain barrier. Physiological differences between humans and mice make translation to the clinic problematic, while monolayer cultures cannot capture the inherently three-dimensional (3D) nature of the blood-brain barrier, which includes close association of the abluminal side of the endothelium with astrocyte foot-processes and pericytes. Here we discuss the central nervous system diseases associated with blood-brain barrier pathology, recent advances in the development of novel 3D blood-brain barrier -on-a-chip systems that better mimic the physiological complexity and structure of human blood-brain barrier, and provide an outlook on how these blood-brain barrier-on-a-chip systems can be used for central nervous system disease modeling. Impact statement The field of microphysiological systems is rapidly evolving as new technologies are introduced and our understanding of organ physiology develops. In this review, we focus on Blood-Brain Barrier (BBB) models, with a particular emphasis on how they relate to neurological disorders such as Alzheimer's disease, multiple sclerosis, stroke, cancer, and vascular malformations. We emphasize the importance of capturing the three-dimensional nature of the brain and the unique architecture of the BBB - something that until recently

CHARACTERIZATION OF BENTONITE FOR ENGINEERED BARRIER SYSTEMS IN RADIOACTIVE WASTE DISPOSAL SITES

Directory of Open Access Journals (Sweden)

Dubravko Domitrović

2012-07-01

Full Text Available Engineered barrier systems are used in radioactive waste disposal sites in order to provide better protection of humans and the environment from the potential hazards associated with the radioactive waste disposal. The engineered barrier systems usually contain cement or clay (bentonite because of their isolation properties and long term performance. Quality control tests of clays are the same for all engineering barrier systems. Differences may arise in the required criteria to be met due for different application. Prescribed clay properties depend also on the type of host rocks. This article presents radioactive waste management based on best international practice. Standard quality control procedures for bentonite used as a sealing barrier in radioactive waste disposal sites are described as some personal experiences and results of the index tests (free swelling index, water adsorption capacity, plasticity limits and hydraulic permeability of bentonite (the paper is published in Croatian.

Prezygotic barriers to hybridization in marine broadcast spawners: reproductive timing and mating system variation.

Directory of Open Access Journals (Sweden)

Carla A Monteiro

Full Text Available Sympatric assemblages of congeners with incomplete reproductive barriers offer the opportunity to study the roles that ecological and non-ecological factors play in reproductive isolation. While interspecific asynchrony in gamete release and gametic incompatibility are known prezygotic barriers to hybridization, the role of mating system variation has been emphasized in plants. Reproductive isolation between the sibling brown algal species Fucus spiralis, Fucus guiryi (selfing hermaphrodite and Fucus vesiculosus (dioecious was studied because they form hybrids in parapatry in the rocky intertidal zone, maintain species integrity over a broad geographic range, and have contrasting mating systems. We compared reproductive synchrony (spawning overlap between the three species at several temporal scales (yearly/seasonal, semilunar/tidal, and hourly during single tides. Interspecific patterns of egg release were coincident at seasonal (single peak in spring to early summer to semilunar timescales. Synthesis of available data indicated that spawning is controlled by semidiurnal tidal and daily light-dark cues, and not directly by semilunar cycles. Importantly, interspecific shifts in timing detected at the hourly scale during single tides were consistent with a partial ecological prezygotic hybridization barrier. The species displayed patterns of gamete release consistent with a power law distribution, indicating a high degree of reproductive synchrony, while the hypothesis of weaker selective constraints for synchrony in selfing versus outcrossing species was supported by observed spawning in hermaphrodites over a broader range of tidal phase than in outcrossers. Synchronous gamete release is critical to the success of external fertilization, while high-energy intertidal environments may offer only limited windows of reproductive opportunity. Within these windows, however, subtle variations in reproductive timing have evolved with the potential to

Field testing of asphalt-emulsion radon-barrier system

International Nuclear Information System (INIS)

Hartley, J.N.; Freeman, H.D.; Baker, E.G.; Elmore, M.R.; Nelson, D.A.; Voss, C.F.; Koehmstedt, P.L.

1981-09-01

Three years of laboratory and field testing have demonstrated that asphalt emulsion seals are effective radon diffusion barriers. Both laboratory and field tests in 1979, 1980 and 1981 have shown that an asphalt emulsion seal can reduce radon fluxes by greater than 99.9%. The effective diffusion coefficient for the various asphalt emulsion admix seals averages about 10 -6 cm 2 /s. The 1981 joint field test is a culmination of all the technology developed to date for asphalt emulsion radon barrier systems. Preliminary results of this field test and the results of the 1980 field test are presented. 18 figures, 6 tables

The Mechanisms and Quantification of the Selective Permeability in Transport Across Biological Barriers : the Example of Kyotorphin

NARCIS (Netherlands)

Serrano, Isa D.; Freire, Joao M.; Carvalho, Miguel V.; Neves, Mafalda; Melo, Manuel N.; Castanho, Miguel A. R. B.

2014-01-01

This paper addresses the mechanisms behind selective endothelial permeability and their regulations. The singular properties of each of the seven blood-tissues barriers. Then, it further revisits the physical, quantitative meaning of permeability, and the way it should be measured based on sound

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

Coping with the knowledge sharing barriers in Product Service Systems design

OpenAIRE

Bertoni, Marco; Larsson, Andreas

2010-01-01

This paper analyzes the knowledge sharing process that characterizes Product Service Systems (PSS) design, drawing on data from an in-depth study in the Swedish manufacturing industry. It categorizes and describes the most relevant knowledge sharing barriers affecting early PSS development phases, discussing them in terms of capabilities to be included in a knowledge engineering system to fulfil the increasing need for knowledge in product-service design. To cope with these barriers, the auth...

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

Effect of inter-species selective interactions on the thermodynamics and nucleation free-energy barriers of a tessellating polyhedral compound

International Nuclear Information System (INIS)

Escobedo, Fernando A.

2016-01-01

The phase behavior and the homogeneous nucleation of an equimolar mixture of octahedra and cuboctahedra are studied using thermodynamic integration, Gibbs-Duhem integration, and umbrella sampling simulations. The components of this mixture are modeled as polybead objects of equal edge lengths so that they can assemble into a space-filling compound with the CsCl crystal structure. Taking as reference the hard-core system where the compound crystal does not spontaneously nucleate, we quantified the effect of inter-species selective interactions on facilitating the disorder-to-order transition. Facet selective and facet non-selective inter-species attractions were considered, and while the former was expectedly more favorable toward the target tessellating structure, the latter was found to be similarly effective in nucleating the crystal compound. Ranges for the strength of attractions and degree of supersaturation were identified where the nucleation free-energy barrier was small enough to foretell a fast process but large enough to prevent spinodal fluctuations that can trap the system in dense metastable states lacking long-range order. At those favorable conditions, the tendency toward the local orientational order favored by packing entropy is amplified and found to play a key role seeding nuclei with the CsCl structure.

The advantages and barriers in the implementation of a substance dependence treatment information system (SDTIS

Directory of Open Access Journals (Sweden)

Sima Ajami

2015-01-01

Full Text Available Addiction is a phenomenon that causes structural changes in different systems of society. Studies show for planning of addiction prevention and treatment, it is necessary to create an information management system. Substance dependence information systems refer to systems which collect, analyse and report data related to substance dependence information. The aim of this study was to identify advantages and barriers to implement Substance Dependence Treatment Information System (SDTIS. This study was a narrative review. Our review divided into three phases: literature collection, assessing, and selection. We employed the following keywords and their combinations in different areas of articles. In this study, 22 of collected articles and reports were selected based on their relevancy. We found many advantages for a substance dependence treatment information system such as recording sufficient, complete and accurate information and easy and timely access to them and monitoring and enhancing the quality of care received by patients. But we may face some concerns for implementing this information system like taking time and funds from client services, being expensive or even problems regarding the quality of data contained in these information systems. There are some important problems in the way of implementing. In order to overcome these issues, we need to raise community awareness.

The advantages and barriers in the implementation of a substance dependence treatment information system (SDTIS).

Science.gov (United States)

Ajami, Sima; Mellat-Karkevandi, Zahra

2015-11-01

Addiction is a phenomenon that causes structural changes in different systems of society. Studies show for planning of addiction prevention and treatment, it is necessary to create an information management system. Substance dependence information systems refer to systems which collect, analyse and report data related to substance dependence information. The aim of this study was to identify advantages and barriers to implement Substance Dependence Treatment Information System (SDTIS). This study was a narrative review. Our review divided into three phases: literature collection, assessing, and selection. We employed the following keywords and their combinations in different areas of articles. In this study, 22 of collected articles and reports were selected based on their relevancy. We found many advantages for a substance dependence treatment information system such as recording sufficient, complete and accurate information and easy and timely access to them and monitoring and enhancing the quality of care received by patients. But we may face some concerns for implementing this information system like taking time and funds from client services, being expensive or even problems regarding the quality of data contained in these information systems. There are some important problems in the way of implementing. In order to overcome these issues, we need to raise community awareness.

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.)

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.)

Aging and Phase Stability of Waste Package Outer Barrier

Energy Technology Data Exchange (ETDEWEB)

Tammy S. Edgecumble Summers

2001-08-23

This Analysis Model Report (AMR) was prepared in accordance with the Work Direction and Planning Document, ''Aging and Phase Stability of Waste Package Outer Barrier'' (CRWMS M&O 1999a). ICN 01 of this AMR was developed following guidelines provided in TWP-MGR-MD-000004 REV 01, ''Technical Work Plan for: Integrated Management of Technical Product Input Department'' (BSC 2001, Addendum B). It takes into consideration the Enhanced Design Alternative II (EDA II), which has been selected as the preferred design for the Engineered Barrier System (EBS) by the License Application Design Selection (LADS) program team (CRWMS M&O 1999b). The salient features of the EDA II design for this model are a waste package (WP) consisting of an outer barrier of Alloy 22 and an inner barrier of Type 316L stainless steel. This report provides information on the phase stability of Alloy 22l, the current waste-package-outer-barrier (WPOB) material. These phase stability studies are currently divided into three general areas: (1) Long-range order reactions; (2) Intermetallic and carbide precipitation in the base metal; and (3) Intermetallic and carbide precipitation in welded samples.

Yucca Mountain engineered barrier system corrosion model (EBSCOM)

International Nuclear Information System (INIS)

King, F.; Kolar, M.; Kessler, J.H.; Apted, M.

2008-01-01

A revised engineered barrier system model has been developed by the Electric Power Research Institute to predict the time dependence of the failure of the drip shields and waste packages in the proposed Yucca Mountain repository. The revised model is based on new information on various corrosion processes developed by the US Department of Energy and others and for a 20-mm-thick waste package design with a double closure lid system. As with earlier versions of the corrosion model, the new EBSCOM code produces a best-estimate of the failure times of the various barriers. The model predicts that only 15% of waste packages will fail within a period of 1 million years. The times for the first corrosion failures are 40,000 years, 336,000 years, and 375,000 years for the drip shield, waste package, and combination of drip shield and the associated waste package, respectively

A method of providing a barrier in a fracture-containing system

DEFF Research Database (Denmark)

2014-01-01

The present invention relates to a method of providing a barrier in a fracture-containing system, comprising: i) Providing a treatment fluid comprising: a) a base fluid; b) an elastomeric material, wherein said elastomeric material comprises at least one polymer capable of crosslinking into an el......The present invention relates to a method of providing a barrier in a fracture-containing system, comprising: i) Providing a treatment fluid comprising: a) a base fluid; b) an elastomeric material, wherein said elastomeric material comprises at least one polymer capable of crosslinking...... into an elastomer, and c) at least one crosslinking agent; ii) Placing the treatment fluid in a fracture-containing system; iii) Allowing the elastomeric material to crosslink with itself to form a barrier in said fracture-containing system; wherein the elastomeric material and/or the crosslinking agent...... are of neutral buoyancy with regard to the base fluid. The invention is contemplated to having utility not only in the oil-drilling industry but also in the plugging of fractures in sewer drains, pipelines etc....

Case history: Vertical barrier wall system for Superfund Site

International Nuclear Information System (INIS)

Koelling, M.A.; Kovac, C.P.; Norris, J.E.

1997-01-01

Design considerations and construction aspects are presented for the installation of a vertical barrier wall system for the Boeing Company at a Superfund Site near Seattle, WA. The construction was performed during 1996. The vertical barrier wall system included: (1) a soil-bentonite (SB) slurry wall, approximately 670 meters (2200 feet) in length, ranging from 12 to 21 meters (40 to 70 feet) in depth; (2) expansion of a cover system over the area enclosed by the SB wall; and (3) surface drainage improvements. Design and construction of the system addressed requirements of a Consent Decree for the site issued in 1993. The paper discusses the development of the design to meet remedial performance goals of preventing migration of contaminants in the soil/groundwater system and aiding aquifer restoration. Secondly, the paper details installation of the SB wall, highlighting the more significant construction issues, which included excavation of the wall through glacially deposited cobbles/boulders/till as well as addressing the severe elevation changes along the wall alignment. Thirdly, the paper presents Quality Assurance (QA) monitoring and testing performed during the construction phase

Cell-to-Cell Contact Results in a Selective Translocation of Maternal Human Immunodeficiency Virus Type 1 Quasispecies across a Trophoblastic Barrier by both Transcytosis and Infection

Science.gov (United States)

Lagaye, S.; Derrien, M.; Menu, E.; Coïto, C.; Tresoldi, E.; Mauclère, P.; Scarlatti, G.; Chaouat, G.; Barré-Sinoussi, F.; Bomsel, M.

2001-01-01

Mother-to-child transmission can occur in utero, mainly intrapartum and postpartum in case of breastfeeding. In utero transmission is highly restricted and results in selection of viral variant from the mother to the child. We have developed an in vitro system that mimics the interaction between viruses, infected cells present in maternal blood, and the trophoblast, the first barrier protecting the fetus. Trophoblastic BeWo cells were grown as a tight polarized monolayer in a two-chamber system. Cell-free virions applied to the apical pole neither crossed the barrier nor productively infected BeWo cells. In contrast, apical contact with human immunodeficiency virus (HIV)-infected peripheral blood mononuclear cells (PBMCs) resulted in transcytosis of infectious virus across the trophoblastic monolayer and in productive infection correlating with the fusion of HIV-infected PBMCs with trophoblasts. We showed that viral variants are selected during these two steps and that in one case of in utero transmission, the predominant maternal viral variant characterized after transcytosis was phylogenetically indistinguishable from the predominant child's virus. Hence, the first steps of transmission of HIV-1 in utero appear to involve the interaction between HIV type 1-infected cells and the trophoblastic layer, resulting in the passage of infectious HIV by transcytosis and by fusion/infection, both leading to a selection of virus quasispecies. PMID:11312350

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.

A novel method to achieve selective emitter for silicon solar cell using low cost pattern-able a-Si thin films as the semi-transparent phosphorus diffusion barrier

International Nuclear Information System (INIS)

Chen, Da Ming; Liang, Zong Cun; Zhuang, Lin; Lin, Yang Huan; Shen, Hui

2012-01-01

Highlights: ► a-Si thin films as semitransparent phosphorus diffusion barriers for solar cell. ► a-Si thin films on silicon wafers were patterned by the alkaline solution. ► Selective emitter was formed with patterned a-Si as diffusion barrier for solar cell. -- Abstract: Selective emitter for silicon solar cell was realized by employing a-Si thin films as the semi-transparent diffusion barrier. The a-Si thin films with various thicknesses (∼10–40 nm) were deposited by the electron-beam evaporation technique. Emitters with sheet resistances from 37 to 145 Ω/□ were obtained via POCl 3 diffusion process. The thickness of the a-Si diffusion barrier was optimized to be 15 nm for selective emitter in our work. Homemade mask which can dissolve in ethanol was screen-printed on a-Si film to make pattern. The a-Si film was then patterned in KOH solution to form finger-like design. Selective emitter was obtainable with one-step diffusion with patterned a-Si film on. Combinations of sheet resistances for the high-/low-level doped regions of 39.8/112.1, 36.2/88.8, 35.4/73.9 were obtained. These combinations are suitable for screen-printed solar cells. This preparation method of selective emitter based on a-Si diffusion barrier is a promising approach for low cost industrial manufacturing.

Barriers in the Implementation of Health Information Systems: A Scoping Review

Directory of Open Access Journals (Sweden)

Florin STAMATIAN

2013-12-01

Full Text Available Context. A well-developed health information system which is implemented according to present standards allows a healthcare quality increase. Our study aims at providing an overview of the barriers which were encountered in the process of implementing the health information systems by reviewing the literature connected to Europe and the United States of America. Methodology. We searched within five databases (Cochrane Library, Google Scholar, PubMed, ScienceDirect and Scopus for the exact phrase ‘implementation health information system’ along with the name of each European country/USA state. Relevance was then tested by scanning titles and abstracts. The third and final step involved assessing all the articles in order to set their relevance and a data extraction tool was created, containing the name of the state/country that the article reports data on, the article citation and the challenges identified. Results. The barriers identified were classified in four major categories: technical, organizational, behavioral/human and financial. Seemingly, Europe (41 articles and USA (20 articles are facing the same issues in the implementation of a health information system. No major difference between EU and non-EU countries was found after our analysis with regards to the identified barriers. Discussion. Even if recommendations and solutions are continuously being developed in order to solve these barriers, the implementation of a new health information system must be very detailed in order to face all these problems. Additionally, further research is required in order to evaluate their impact on the successful implementation of a health information system.

An evaluation of the fire barrier system thermo-lag 330-1

International Nuclear Information System (INIS)

Nowlen, S.P.

1994-09-01

This report presents the results of three fire endurance tests and one ampacity derating test set of the fire barrier system Thermo-Lag 330-1 Subliming Coating. Each test was performed using cable tray specimens protected by a nominal three-hour fire barrier envelope comprised of two layers of nominal 1/2 inch thick material. The fire barrier systems for two of the three fire endurance test articles and for the ampacity derating test article were installed in accordance with the manufacturer's installations procedures. The barrier system for the third fire endurance test article was a full reproduction of one of the original manufacturer's qualification test articles. This final test article included certain installation enhancements not considered typical of current nuclear power plant installations. The primary criteria for fire endurance performance evaluation was based on cable circuit integrity testing. Secondary consideration was also given to the temperature rise limits set forth in the ASTM E119 standard fire barrier test procedure. All three of the fire endurance specimens failed prematurely. Circuit integrity failures for the two fire endurance test articles with procedures-based installations were recorded at approximately 76 and 59 minutes into the exposures for a 6 inch wide and 12 inch wide cable tray respectively. Temperature excursion failures (single point) for these two test articles were noted at approximately 65 and 56 minutes respectively. The first circuit integrity failure for the full reproduction test article was recorded approximately 119 minutes into the exposure, and the first temperature excursion failure for this test article was recorded approximately 110 minutes into the exposure

The intestinal barrier function and its involvement in digestive disease

Directory of Open Access Journals (Sweden)

Eloísa Salvo-Romero

2015-11-01

Full Text Available The gastrointestinal mucosal surface is lined with epithelial cells representing an effective barrier made up with intercellular junctions that separate the inner and the outer environments, and block the passage of potentially harmful substances. However, epithelial cells are also responsible for the absorption of nutrients and electrolytes, hence a semipermeable barrier is required that selectively allows a number of substances in while keeping others out. To this end, the intestine developed the "intestinal barrier function", a defensive system involving various elements, both intra- and extracellular, that work in a coordinated way to impede the passage of antigens, toxins, and microbial byproducts, and simultaneously preserves the correct development of the epithelial barrier, the immune system, and the acquisition of tolerance against dietary antigens and the intestinal microbiota. Disturbances in the mechanisms of the barrier function favor the development of exaggerated immune responses; while exact implications remain unknown, changes in intestinal barrier function have been associated with the development of inflammatory conditions in the gastrointestinal tract. This review details de various elements of the intestinal barrier function, and the key molecular and cellular changes described for gastrointestinal diseases associated with dysfunction in this defensive mechanism.

Preliminary engineering specifications for a test demonstration multilayer protective barrier cover system

International Nuclear Information System (INIS)

Phillips, S.J.; Gilbert, T.W.; Adams, M.R.

1985-03-01

This report presents preliminary engineering specifications for a test protective barrier cover system and support radiohydrology facility to be constructed at the Hanford Protective Barrier Test Facility (PBTF). Construction of this test barrier and related radiohydrology facility is part of a continuing effort to provide construction experience and performance evaluation of alternative barrier designs used for long-term isolation of disposed radioactive waste materials. Design specifications given in this report are tentative, based on interim engineering and computer simulation design efforts. Final definitive design specifications and engineering prints will be produced in FY 1986. 6 refs., 10 figs., 1 tab

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

Social barriers to pathogen transmission in wild animal populations

Energy Technology Data Exchange (ETDEWEB)

Loehle, C.

1995-03-01

Diseases and pathogens are receiving increasing recognition as sources of mortality in animal populations. Immune system strength is clearly important in fending off pathogen attack. Physical barriers to pathogen entry are also important. Various individual behaviors are efficacious in reducing contact with diseases and pests. This paper focuses on a fourth mode of defense: social barriers to transmission. Various social behaviors have pathogen transmission consequences. Selective pressures on these social behaviors may therefore exist. Effects on pathogen transmission of mating strategies, social avoidance, group size, group isolation, and other behaviors are explored. It is concluded that many of these behaviors may have been affected by selection pressures to reduce transmission of pathogens. 84 refs., 1 tab.

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

Thermophysical and Thermomechanical Properties of Thermal Barrier Coating Systems

Science.gov (United States)

Zhu, Dongming; Miller, Robert A.

2000-01-01

Thermal barrier coatings have been developed for advanced gas turbine and diesel engine applications to improve engine reliability and fuel efficiency. However, the issue of coating durability under high temperature cyclic conditions is still of major concern. The coating failure is closely related to thermal stresses and oxidation in the coating systems. Coating shrinkage cracking resulting from ceramic sintering and creep at high temperatures can further accelerate the coating failure process. The purpose of this paper is to address critical issues such as ceramic sintering and creep, thermal fatigue and their relevance to coating life prediction. Novel test approaches have been established to obtain critical thermophysical and thermomechanical properties of the coating systems under near-realistic temperature and stress gradients encountered in advanced engine systems. Emphasis is placed on the dynamic changes of the coating thermal conductivity and elastic modulus, fatigue and creep interactions, and resulting failure mechanisms during the simulated engine tests. Detailed experimental and modeling results describing processes occurring in the thermal barrier coating systems provide a framework for developing strategies to manage ceramic coating architecture, microstructure and properties.

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.

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

Proxy records of Holocene storm events in coastal barrier systems: Storm-wave induced markers

Science.gov (United States)

Goslin, Jérôme; Clemmensen, Lars B.

2017-10-01

Extreme storm events in the coastal zone are one of the main forcing agents of short-term coastal system behavior. As such, storms represent a major threat to human activities concentrated along the coasts worldwide. In order to better understand the frequency of extreme events like storms, climate science must rely on longer-time records than the century-scale records of instrumental weather data. Proxy records of storm-wave or storm-wind induced activity in coastal barrier systems deposits have been widely used worldwide in recent years to document past storm events during the last millennia. This review provides a detailed state-of-the-art compilation of the proxies available from coastal barrier systems to reconstruct Holocene storm chronologies (paleotempestology). The present paper aims (I) to describe the erosional and depositional processes caused by storm-wave action in barrier and back-barrier systems (i.e. beach ridges, storm scarps and washover deposits), (ii) to understand how storm records can be extracted from barrier and back-barrier sedimentary bodies using stratigraphical, sedimentological, micro-paleontological and geochemical proxies and (iii) to show how to obtain chronological control on past storm events recorded in the sedimentary successions. The challenges that paleotempestology studies still face in the reconstruction of representative and reliable storm-chronologies using these various proxies are discussed, and future research prospects are outlined.

Potential Pathways for CNS Drug Delivery Across the Blood-Cerebrospinal Fluid Barrier

Science.gov (United States)

Strazielle, Nathalie; Ghersi-Egea, Jean-François

2016-01-01

The blood-brain interfaces restrict the cerebral bioavailability of pharmacological compounds. Various drug delivery strategies have been developed to improve drug penetration into the brain. Most strategies target the microvascular endothelium forming the blood-brain barrier proper. Targeting the blood-cerebrospinal fluid (CSF) barrier formed by the epithelium of the choroid plexuses in addition to the blood-brain barrier may offer added-value for the treatment of central nervous system diseases. For instance, targeting the CSF spaces, adjacent tissue, or the choroid plexuses themselves is of interest for the treatment of neuroinflammatory and infectious diseases, cerebral amyloid angiopathy, selected brain tumors, hydrocephalus or neurohumoral dysregulation. Selected CSF-borne materials seem to reach deep cerebral structures by mechanisms that need to be understood in the context of chronic CSF delivery. Drug delivery through both barriers can reduce CSF sink action towards parenchymal drugs. Finally, targeting the choroid plexus-CSF system can be especially relevant in the context of neonatal and pediatric diseases of the central nervous system. Transcytosis appears the most promising mechanism to target in order to improve drug delivery through brain barriers. The choroid plexus epithelium displays strong vesicular trafficking and secretory activities that deserve to be explored in the context of cerebral drug delivery. Folate transport and exosome release into the CSF, plasma protein transport, and various receptor-mediated endocytosis pathways may prove useful mechanisms to exploit for efficient drug delivery into the CSF. This calls for a clear evaluation of transcytosis mechanisms at the blood-CSF barrier, and a thorough evaluation of CSF drug delivery rates. PMID:27464721

Hanford Permanent Isolation Barrier Program: Asphalt technology development

International Nuclear Information System (INIS)

Freeman, H.D.; Romine, R.A.

1994-11-01

An important component of the Hanford Permanent Isolation Barrier is the use of a two-layer composite asphalt system, which provides backup water diversion capabilities if the primary capillary barrier fails to meet infiltration goals. Because of asphalt's potential to perform to specification over the 1000-year design life criterion, a composite asphalt barrier (HMAC/fluid-applied polymer-modified asphalt) is being considered as an alternative to the bentonite clay/high density poly(ethylene) barriers for the low-permeability component of the Hanford Permanent Isolation Barrier. The feasibility of using asphalt as a long-term barrier is currently being studied. Information that must be known is the ability of asphalt to retain desirable physical properties over a period of 1000 years. This paper presents the approach for performing accelerated aging tests and evaluating the performance of samples under accelerated conditions. The results of these tests will be compared with asphalt artifact analogs and the results of modeling the degradation of the selected asphalt composite to make life-cycle predictions

Barrier and system performances within a safety case: their functioning and evolution with time

International Nuclear Information System (INIS)

Hedin, A.; Voinis, S.; Fillion, E.; Keller, S.; Lalieux, Ph.; Nachmilner, L.; Nys, V.; Rodriguez, J.; Sevougian, D.; Wollrath, J.

2002-01-01

The following six questions were used as the basis for the discussions in a Working Group: - 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 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 are barriers and system performances, as a function of time, evaluated (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)

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

Integrated control of the wastewater system – potentials and barriers

DEFF Research Database (Denmark)

Mollerup, Ane Loft; Grum, Morten; Muschalla, Dirk

2013-01-01

Applying integrated control to a sewer system and wastewater treatment plant often leads to additional benefits for both systems when compared to controlling them independently. However, barriers such as a lack of incentive for utilities to put this type of control in place mean that in practice...

Engineered barrier experiment. Power control and data acquisition systems

International Nuclear Information System (INIS)

Alberdi, J.; Barcala, J.M.; Gamero, E.; Martin, P.L.; Molinero, A.; Navarrete, J.J.; Yuste, C.

1997-01-01

The engineered barrier concept for the storage of radioactive wastes is being tested at almost full scale at CIEMAT facilities. A data acquisition and control is an element of this experiment. This system would be operating for next three years. (Author)

Effect of vadose zone on the steady-state leakage rates from landfill barrier systems

International Nuclear Information System (INIS)

Celik, B.; Rowe, R.K.; Unlue, K.

2009-01-01

Leakage rates are evaluated for a landfill barrier system having a compacted clay liner (CCL) underlain by a vadose zone of variable thickness. A numerical unsaturated flow model SEEP/W is used to simulate the moisture flow regime and steady-state leakage rates for the cases of unsaturated zones with different soil types and thicknesses. The results of the simulations demonstrate that harmonic mean hydraulic conductivity of coarse textured vadose zones is 3-4 orders of magnitude less than saturated hydraulic conductivity; whereas, the difference is only one order of magnitude for fine textured vadose zones. For both coarse and fine textured vadose zones, the effective hydraulic conductivity of the barrier system and the leakage rate to an underlying aquifer increases with increasing thickness of the vadose zone and ultimately reaches an asymptotic value for a coarse textured vadose zone thickness of about 10 m and a fine textured vadose zone thickness of about 5 m. Therefore, the fine and coarse textured vadose zones thicker than about 5 m and 10 m, respectively, act as an effective part of the barrier systems examined. Although the thickness of vadose zone affects the effective hydraulic conductivity of the overall barrier system, the results demonstrated that the hydraulic conductivity of the CCL is the dominant factor controlling the steady-state leakage rates through barrier systems having single low permeability clay layers

Influences of engineered barrier systems on low-level radioactive waste disposal

International Nuclear Information System (INIS)

Buckley, L.P.

1987-09-01

There are major differences between the current practices of shallow land burial and alternative concepts for the disposal of low-level radioactive wastes. Additional protection provided with engineered barrier systems can overcome major concerns the public has with shallow land burial: subsidence; percolating ground waters; radionuclide migration; and the vulnerability of shallow trenches to intrusion. The presence of a variety of engineered barriers to restrict water movement, retain radionuclides and to prevent plant animal or human intrusion leads to significant changes to input data for performance assessment models. Several programs which are underway to more accurately predict the long-term performance of engineered barriers for low-level waste will be described

Influences of engineered barrier systems on low-level radioactive waste disposal

Energy Technology Data Exchange (ETDEWEB)

Buckley, L. P.

1987-09-15

There are major differences between the current practices of shallow land burial and alternative concepts for the disposal of low-level radioactive wastes. Additional protection provided with engineered barrier systems can overcome major concerns the public has with shallow land burial: subsidence; percolating ground waters; radionuclide migration; and the vulnerability of shallow trenches to intrusion. The presence of a variety of engineered barriers to restrict water movement, retain radionuclides and to prevent plant animal or human intrusion leads to significant changes to input data for performance assessment models. Several programs which are underway to more accurately predict the long-term performance of engineered barriers for low-level waste will be described.

Sub-barrier fusion of Si+Si systems

Science.gov (United States)

Colucci, G.; Montagnoli, G.; Stefanini, A. M.; Bourgin, D.; Čolović, P.; Corradi, L.; Courtin, S.; Faggian, M.; Fioretto, E.; Galtarossa, F.; Goasduff, A.; Haas, F.; Mazzocco, M.; Scarlassara, F.; Stefanini, C.; Strano, E.; Urbani, M.; Szilner, S.; Zhang, G. L.

2017-11-01

The near- and sub-barrier fusion excitation function has been measured for the system 30Si+30Si at the Laboratori Nazionali di Legnaro of INFN, using the 30Si beam of the XTU Tandem accelerator in the energy range 47 - 90 MeV. A set-up based on a beam electrostatic deflector was used for detecting fusion evaporation residues. The measured cross sections have been compared to previous data on 28Si+28Si and Coupled Channels (CC) calculations have been performed using M3Y+repulsion and Woods-Saxon potentials, where the lowlying 2+ and 3- excitations have been included. A weak imaginary potential was found to be necessary to reproduce the low energy 28Si+28Si data. This probably simulates the effect of the oblate deformation of this nucleus. On the contrary, 30Si is a spherical nucleus, 30Si+30Si is nicely fit by CC calculations and no imaginary potential is needed. For this system, no maximum shows up for the astrophysical S-factor so that we have no evidence for hindrance, as confirmed by the comparison with CC calculations. The logarithmic derivative of the two symmetric systems highlights their different low energy trend. A difference can also be noted in the two barrier distributions, where the high-energy peak present in 28Si+28Si is not observed for 30Si+30Si, probably due to the weaker couplings in last case.

Sub-barrier fusion of Si+Si systems

Directory of Open Access Journals (Sweden)

Colucci G.

2017-01-01

Full Text Available The near- and sub-barrier fusion excitation function has been measured for the system 30Si+30Si at the Laboratori Nazionali di Legnaro of INFN, using the 30Si beam of the XTU Tandem accelerator in the energy range 47 - 90 MeV. A set-up based on a beam electrostatic deflector was used for detecting fusion evaporation residues. The measured cross sections have been compared to previous data on 28Si+28Si and Coupled Channels (CC calculations have been performed using M3Y+repulsion and Woods-Saxon potentials, where the lowlying 2+ and 3− excitations have been included. A weak imaginary potential was found to be necessary to reproduce the low energy 28Si+28Si data. This probably simulates the effect of the oblate deformation of this nucleus. On the contrary, 30Si is a spherical nucleus, 30Si+30Si is nicely fit by CC calculations and no imaginary potential is needed. For this system, no maximum shows up for the astrophysical S-factor so that we have no evidence for hindrance, as confirmed by the comparison with CC calculations. The logarithmic derivative of the two symmetric systems highlights their different low energy trend. A difference can also be noted in the two barrier distributions, where the high-energy peak present in 28Si+28Si is not observed for 30Si+30Si, probably due to the weaker couplings in last case.

Regulatory analysis for the use of underground barriers at the Hanford Site tank farms

International Nuclear Information System (INIS)

Hampsten, K.L.

1994-01-01

Sixty-seven of the single-shell tanks at the Hanford Site, Richland, Washington, are assumed to have leaked in the past. Some of the waste retrieval options being considered, such as past-practice sluicing (a process that uses hot water to dislodge waste for subsequent removal by pumping), have the potential for increasing releases of dangerous waste from these tanks. Underground barrier systems are being evaluated as a method to mitigate releases of tank waste to the soil and groundwater that may occur during retrieval activities. The following underground barrier system options are among those being evaluated to determine whether their construction at the Single-Shell Tank Farms is viable. (1) A desiccant barrier would be created by circulating air through the subsurface soil to lower and then maintain the water saturation below the levels required for liquids to flow. (2) An injected materials barrier would be created by injecting materials such as grout or silica into the subsurface soils to form a barrier around and under a given tank or tank farm. (3) A cryogenic barrier would be created by freezing subsurface soils in the vicinity of a tank or tank farm. An analysis is provided of the major regulatory requirements that may impact full scale construction and operation of an underground barrier system and a discussion of factors that should be considered throughout the barrier selection process, irrespective of the type of underground barrier system being considered. However, specific barrier systems will be identified when a given regulation will have significant impact on a particular type of barrier technology. Appendix A provides a matrix of requirements applicable to construction and operation of an underground barrier system

Linear and non-linear energy barriers in systems of interacting single-domain ferromagnetic particles

International Nuclear Information System (INIS)

Petrila, Iulian; Bodale, Ilie; Rotarescu, Cristian; Stancu, Alexandru

2011-01-01

A comparative analysis between linear and non-linear energy barriers used for modeling statistical thermally-excited ferromagnetic systems is presented. The linear energy barrier is obtained by new symmetry considerations about the anisotropy energy and the link with the non-linear energy barrier is also presented. For a relevant analysis we compare the effects of linear and non-linear energy barriers implemented in two different models: Preisach-Neel and Ising-Metropolis. The differences between energy barriers which are reflected in different coercive field dependence of the temperature are also presented. -- Highlights: → The linear energy barrier is obtained from symmetry considerations. → The linear and non-linear energy barriers are calibrated and implemented in Preisach-Neel and Ising-Metropolis models. → The temperature and time effects of the linear and non-linear energy barriers are analyzed.

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

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

Engineered barrier systems (EBS) in the context of the entire safety case

International Nuclear Information System (INIS)

2003-01-01

A joint NEA-EC workshop entitled 'Engineered Barrier Systems (EBS) in the Context of the Entire Safety Case' was organised in Oxford on 25-27 September 2002 and hosted by United Kingdom Nirex Limited. The main objectives of the workshop were to provide a status report on engineered barrier systems in various national radioactive waste management programmes considering deep geological disposal; to establish the value to member countries of a project on EBS; and to define such a project's scope, timetable and modus operandi. This report presents the outcomes of this workshop. (author)

Engineered Barrier Systems (EBS) in the Context of the Entire Safety Case

International Nuclear Information System (INIS)

2005-01-01

A joint NEA-EC workshop entitled ''Engineered Barrier Systems (EBS) in the Context of the Entire Safety Case'' was organised in Oxford on 25-27 September 2002 and hosted by United Kingdom Nirex Limited. The main objectives of the workshop were to provide a status report on engineered barrier systems in various national radioactive waste management programmes considering deep geological disposal; to establish the value to member countries of a project on EBS; and to define such a project scope, timetable and modus operandi. This report presents the outcomes of this workshop. (author)

Evaluation of the Effectiveness of Stormwater Decision Support Tools for Infrastructure Selection and the Barriers to Implementation

Science.gov (United States)

Spahr, K.; Hogue, T. S.

2016-12-01

Selecting the most appropriate green, gray, and / or hybrid system for stormwater treatment and conveyance can prove challenging to decision markers across all scales, from site managers to large municipalities. To help streamline the selection process, a multi-disciplinary team of academics and professionals is developing an industry standard for selecting and evaluating the most appropriate stormwater management technology for different regions. To make the tool more robust and comprehensive, life-cycle cost assessment and optimization modules will be included to evaluate non-monetized and ecosystem benefits of selected technologies. Initial work includes surveying advisory board members based in cities that use existing decision support tools in their infrastructure planning process. These surveys will qualify the decisions currently being made and identify challenges within the current planning process across a range of hydroclimatic regions and city size. Analysis of social and other non-technical barriers to adoption of the existing tools is also being performed, with identification of regional differences and institutional challenges. Surveys will also gage the regional appropriateness of certain stormwater technologies based off experiences in implementing stormwater treatment and conveyance plans. In additional to compiling qualitative data on existing decision support tools, a technical review of components of the decision support tool used will be performed. Gaps in each tool's analysis, like the lack of certain critical functionalities, will be identified and ease of use will be evaluated. Conclusions drawn from both the qualitative and quantitative analyses will be used to inform the development of the new decision support tool and its eventual dissemination.

Development of a Mechanical Analysis System Considering Chemical Transitions of Barrier Materials

International Nuclear Information System (INIS)

Sahara, F.; Murakami, T.; Ito, H.; Kobayashi, I.; Yokozeki, K.

2006-01-01

An analysis system for the long-term mechanical behavior of barrier materials (MACBECE: Mechanical Analysis system considering Chemical transitions of Bentonite-based and Cement-based materials) was developed in order to improve the reliability of the evaluation of the hydraulic field that is one of the important environmental conditions in the safety assessment of the TRU waste disposal in Japan. The MACBECE is a system that calculates the deformation of barrier materials using their chemical property changes as inputs, and subsequently their hydraulic conductivity taking both their chemical property changes and deformation into consideration. This paper provides a general description of MACBECE and the results of experimental analysis carried out using MACBECE. (authors)

Organizational, interface, and financial barriers to the commercial development of community energy systems

Energy Technology Data Exchange (ETDEWEB)

Schladale, R.; Ritschard, R.

1979-12-01

The scope of this analysis was limited to systems producing electricity - the output of a community energy system typically falling in the range 10 kW to 150 MW. The purpose of this study was to identify the barriers that groups and individuals will face when attempting to commercialize community energy systems. Three particular classes of barriers were investigated: those within the organization attempting the commercialization, those that arise from attempts to link the community system with an electric utility, and those that impede the flow of investment capital into community energy systems. In summary, three general observations regarding community energy systems may be distilled from this study. First, although many barriers exist to the commercialization of the systems, few if any appear unresolvable. Perhaps most challenginng will be the problem of expanding the use of cogeneration and municipal sold waste while at the same time maintaining or improving ambient air quality. Second, the financial subsidies required to make community systems competitive are not extraordinary. Indeed, with the exception of photovoltaics they should not amount to more than about 10% of capital cost of the new systems, and mass production may eliminate the need for subsidies altogether at some point in the future. Third, the administrative and regulatory procedures required to make community energy systems viable appear to be taking shape in a positive and timely fashion.

Project Guarantee 1985. Final repository for high-level radioactive wastes: The system of safety barriers

International Nuclear Information System (INIS)

Anon.

1985-01-01

Final disposal of radioactive waste involves preventing the waste from returning from the repository location into the biosphere by means of successively arranged containment measures known as safety barriers. In the present volume NGB 85-04 of the series of reports for Project 'Guarantee' 1985, the safety barrier system for the type C repository for high-level waste is described. The barrier parameters which are relevant for safety analysis are quantified and associated error limits and data scatter are given. The aim of the report is to give a summary documentation of the safety analysis input data and their scientific background. For secure containment of radioactive waste safety barriers are used which effectively limit the release of radioactive material from the repository (release barriers) and effectively retard the entry of the original radioactive material into the biosphere (time barriers). Safety barriers take the form of both technically constructed containment measures and the siting of the repository in suitable geological formations. The technical safety barrier system in the case of high-level waste comprises: the waste solidification matrix (borosilicate glass), massive steel canisters, encasement of the waste canisters, encasement of the waste canisters in highly compacted bentonite, sealing of vacant storage space and access routes on repository closure. The natural geological safety barriers - the host rock and overlying formations provide sufficiently long deep groundwater flow times from the repository location to the earth's surface and for additional lengthening of radionuclide migration times by means of various chemical and physical retardation mechanisms. The stability of the geological formations is so great that hydrogeological system is protected for a sufficient length of time from deterioration caused, in particular, by erosion. Observations in the final section of the report indicate that input data for the type C repository safety

Sub-barrier fusion and transfers in the 40Ca + 58,64Ni systems

Science.gov (United States)

Bourgin, D.; Courtin, S.; Haas, F.; Goasduff, A.; Stefanini, A. M.; Montagnoli, G.; Montanari, D.; Corradi, L.; Huiming, J.; Scarlassara, F.; Fioretto, E.; Simenel, C.; Rowley, N.; Szilner, S.; Mijatović, T.

2016-05-01

Fusion cross sections have been measured in the 40Ca + 58Ni and 40Ca + 64Ni systems at energies around and below the Coulomb barrier. The 40Ca beam was delivered by the XTU Tandem accelerator of the Laboratori Nazionali di Legnaro and evaporation residues were measured at very forward angles with the LNL electrostatic beam deflector. Coupled-channels calculations were performed which highlight possible strong effects of neutron transfers on the fusion below the barrier in the 40Ca + 64Ni system. Microscopic time-dependent Hartree-Fock calculations have also been performed for both systems. Preliminary results are shown.

Experimental Approach of Fault Movement on an Engineered Barrier System

International Nuclear Information System (INIS)

Lee, Minsoo; Choi, Heuijoo; Kim, Heuna

2012-01-01

Safety evaluation of an engineered barrier system against fault movement at underground disposal region for high level waste (HLW) is tried using a miniature bore-shear apparatus. For the purpose, a miniature bore-shear apparatus simulating an EBS (engineered barrier system) was manufactured in 1/30 scale. And using the developed apparatus, bore-shear tests were performed twice. During the tests, pressure variations were checked at 6 points around buffer zone, and then a rotational angle of the test vessel was checked. The achieved pressure data were compared with those from analytical modeling, which is based on Drucker-Prager model. At initial shearing step, high pressure was recorded at some point but it decreased rapidly. For the better understanding of fault movement, the modification of an analytical model and the accumulation of experimental experience were required

Experimental Approach of Fault Movement on an Engineered Barrier System

Energy Technology Data Exchange (ETDEWEB)

Lee, Minsoo; Choi, Heuijoo; Kim, Heuna [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-03-15

Safety evaluation of an engineered barrier system against fault movement at underground disposal region for high level waste (HLW) is tried using a miniature bore-shear apparatus. For the purpose, a miniature bore-shear apparatus simulating an EBS (engineered barrier system) was manufactured in 1/30 scale. And using the developed apparatus, bore-shear tests were performed twice. During the tests, pressure variations were checked at 6 points around buffer zone, and then a rotational angle of the test vessel was checked. The achieved pressure data were compared with those from analytical modeling, which is based on Drucker-Prager model. At initial shearing step, high pressure was recorded at some point but it decreased rapidly. For the better understanding of fault movement, the modification of an analytical model and the accumulation of experimental experience were required.

Project Guarantee 1985. Final repository for low- and intermediate-level radioactive wastes: The system of safety barriers

International Nuclear Information System (INIS)

Anon.

1985-01-01

The safety barrier system for the type B repository for low- and intermediate-level waste is described. The barrier parameters which are relevant for safety analysis are quantified and associated error limits and data scatter are given. The aim of the report is to give a summary documentation of the safety analysis input data and their scientific background. For secure containment of radioactive waste safety barriers are used which effectively limit the release of radioactive material from the repository (release barriers) and effectively retard the entry of the original radioactive material into the biosphere (time barriers). In the case of low- and intermediate-level waste the technical safety barrier system comprises: waste solidification matrix (cement, bitumen and resin), immobilisation of the waste packages in containers using liquid cement, concrete repository containers, backfilling of remaining vacant storage space with special concrete, concrete lining of the repository caverns, sealing of access tunnels on final closure of the repository. Natural geological safety barriers - host rock and overlying formations - have the following important functions. Because of its stability, the host rock in the repository zone protects the technical safety barrier system from destruction caused by climatic effects and erosion for a sufficient length of time. It also provides for low water flow and favourable chemistry (reducing conditions)

A novel muscarinic receptor ligand which penetrates the blood brain barrier and displays in vivo selectivity for the m2 subtype

International Nuclear Information System (INIS)

Gitler, M.S.; Cohen, V.I.; De La Cruz, R.; Boulay, S.F.; Jin, B.; Zeeberg, B.R.; Reba, R.C.

1993-01-01

Alzheimer's disease (AD) involves selective loss of muscarinic m2, but not m1, subtype neuroreceptors in the posterior parietal cortex of the human brain. Emission tomographic study of the loss of m2 receptors in AD is limited by the fact that there is currently no available m2-selective radioligand which can penetrate the blood-brain barrier. In our efforts to prepare such a radioligand, the authors have used competition studies against currently existing muscarinic receptor radioligands to infer the in vitro and in vivo properties of a novel muscarinic receptor ligand, 5-[[4-[4-(diisobutylamino)butyl]-1-phenyl]acetyl]-10,11-dihydro-5H-dibenzo[b,e][1,4]diazepin-11-one (DIBD). In vitro competition studies against [ 3 H](R)-3-quinuclidinylbenzilate ([ 3 H]QNB) and [ 3 H]N-methylscopolamine ([ 3 H]NMS), using membranes derived from transfected cells expressing only m1, m2, m3, or m4 receptor subtypes, indicate that DIBD is selective for m2/m4 over m1/m3. In vivo competition studies against (R,R)-[ 125 I]IQNB indicate that DIBD crosses the blood brain barrier (BBB). The relationship of the regional percentage decrease in (R,R)-[ 125 I]IQNB versus the percentage of each of the receptor subtypes indicates that DIBD competes more effectively in those brain regions which are known to be enriched in the m2, relative to the m1, m3, and m4, receptor subtype; however, analysis of the data using a mathematical model shows that caution is required when interpreting the in vivo results. The authors conclude that a suitably radiolabeled derivative of DIBD may be of potential use in emission tomographic study of changes in m2 receptors in the central nervous system

Attitude towards the incorporation of the selective collection of biowaste in a municipal solid waste management system. A case study

International Nuclear Information System (INIS)

Bernad-Beltrán, D.; Simó, A.; Bovea, M.D.

2014-01-01

Highlights: • Attitude towards incorporating biowaste selective collection is analysed. • Willingness to participate and to pay in biowaste selective collection is obtained. • Socioeconomic aspects affecting WtParticipate and WtPay are identified. - Abstract: European waste legislation has been encouraging for years the incorporation of selective collection systems for the biowaste fraction. European countries are therefore incorporating it into their current municipal solid waste management (MSWM) systems. However, this incorporation involves changes in the current waste management habits of households. In this paper, the attitude of the public towards the incorporation of selective collection of biowaste into an existing MSWM system in a Spanish municipality is analysed. A semi-structured telephone interview was used to obtain information regarding aspects such as: level of participation in current waste collection systems, willingness to participate in selective collection of biowaste, reasons and barriers that affect participation, willingness to pay for the incorporation of the selective collection of biowaste and the socioeconomic characteristics of citizens who are willing to participate and pay for selective collection of biowaste. The results showed that approximately 81% of the respondents were willing to participate in selective collection of biowaste. This percentage would increase until 89% if the Town Council provided specific waste bins and bags, since the main barrier to participate in the new selective collection system is the need to use specific waste bin and bags for the separation of biowaste. A logit response model was applied to estimate the average willingness to pay, obtaining an estimated mean of 7.5% on top of the current waste management annual tax. The relationship of willingness to participate and willingness to pay for the implementation of this new selective collection with the socioeconomic variables (age, gender, size of the

Attitude towards the incorporation of the selective collection of biowaste in a municipal solid waste management system. A case study

Energy Technology Data Exchange (ETDEWEB)

Bernad-Beltrán, D. [Department of Mechanical Engineering and Construction, Universitat Jaume I, Av Sos Baynat s/n, E12071 Castellón (Spain); Simó, A. [Department of Mathematics, Universitat Jaume I, Av Sos Baynat s/n, E12071 Castellón (Spain); Bovea, M.D., E-mail: bovea@uji.es [Department of Mechanical Engineering and Construction, Universitat Jaume I, Av Sos Baynat s/n, E12071 Castellón (Spain)

2014-12-15

Highlights: • Attitude towards incorporating biowaste selective collection is analysed. • Willingness to participate and to pay in biowaste selective collection is obtained. • Socioeconomic aspects affecting WtParticipate and WtPay are identified. - Abstract: European waste legislation has been encouraging for years the incorporation of selective collection systems for the biowaste fraction. European countries are therefore incorporating it into their current municipal solid waste management (MSWM) systems. However, this incorporation involves changes in the current waste management habits of households. In this paper, the attitude of the public towards the incorporation of selective collection of biowaste into an existing MSWM system in a Spanish municipality is analysed. A semi-structured telephone interview was used to obtain information regarding aspects such as: level of participation in current waste collection systems, willingness to participate in selective collection of biowaste, reasons and barriers that affect participation, willingness to pay for the incorporation of the selective collection of biowaste and the socioeconomic characteristics of citizens who are willing to participate and pay for selective collection of biowaste. The results showed that approximately 81% of the respondents were willing to participate in selective collection of biowaste. This percentage would increase until 89% if the Town Council provided specific waste bins and bags, since the main barrier to participate in the new selective collection system is the need to use specific waste bin and bags for the separation of biowaste. A logit response model was applied to estimate the average willingness to pay, obtaining an estimated mean of 7.5% on top of the current waste management annual tax. The relationship of willingness to participate and willingness to pay for the implementation of this new selective collection with the socioeconomic variables (age, gender, size of the

The role of engineered barriers in spent fuel disposal

International Nuclear Information System (INIS)

Vokal, A.

1997-01-01

Engineered, i.e. man-made, barriers in underground spent fuel disposal include the waste form itself, the fuel cladding, the storage container, and the isolating system made of buffering, filling, and sealing materials. The parameters of and requirements for each of the components are highlighted, and the methodology of materials selection is discussed. (P.A.)

Progress in waste package and engineered barrier system performance assessment and design

International Nuclear Information System (INIS)

Van Luik, A.; Stahl, D.; Harrison, D.

1993-01-01

As part of the U.S. Department of Energy's evaluation of site suitability for a potential high-level radioactive waste repository, long-term interactions between the engineered barrier system and the site must be determined. This requires a waste-package/engineered-system design, a description of the environment around the emplacement zone, and models that simulate operative processes describing these engineered/natural systems interactions. Candidate designs are being evaluated, including a more robust, multi-barrier waste package, and a drift emplacement mode. Tools for evaluating designs, and emplacement mode are the currently available waste-package/engineered-system performance assessment codes development for the project. For assessments that support site suitability, environmental impact, or licensing decisions, more capable codes are needed. Code capability requirements are being written, and existing codes are to be evaluated against those requirements. Recommendations are being made to focus waste-packaging/engineered-system code-development

Barriers and opportunities: A review of selected successful energy-efficiency programs

International Nuclear Information System (INIS)

Worrell, Ernst; Price, Lynn

2001-01-01

In industry, barriers may exist at various points in the decision making process, and in the implementation and management of measures to improve energy efficiency. Barriers may take many forms, and are determined by the business environment and include decision-making processes, energy prices, lack of information, a lack of confidence in the information, or high transaction costs for obtaining reliable information, as well as limited capital availability. Other barriers are the ''invisibility'' of energy efficiency measures and the difficulty of quantifying the impacts, and slow diffusion of innovative technology into markets while firms typically under-invest in R and D, despite the high pay-backs. Various programs try to reduce the barriers to improve the uptake of innovative technologies. A wide array of policies has been used and tested in the industrial sector in industrialized countries, with varying success rates. We review some new approaches to industrial energy efficiency improvement in industrialized countries, focusing on voluntary agreements

Chemical gel barriers as low-cost alternative to containment and in situ cleanup of hazardous wastes to protect groundwater

International Nuclear Information System (INIS)

1997-01-01

Chemical gel barriers are being considered as a low-cost alternative for containment and in situ cleanup of hazardous wastes to protect groundwater. Most of the available gels in petroleum application are non-reactive and relative impermeable, providing a physical barriers for all fluids and contaminants. However, other potential systems can be envisioned. These systems could include gels that are chemically reactive and impermeable such that most phase are captured by the barriers but the contaminants could diffuse through the barriers. Another system that is chemically reactive and permeable could have potential applications in selectivity capturing contaminants while allowing water to pass through the barriers. This study focused on chemically reactive and permeable gel barriers. The gels used in experiment are DuPont LUDOX SM colloidal silica gel and Pfizer FLOPAAM 1330S hydrolyzed polyacrylamide (HPAM) gel

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...

Sub-barrier fusion and transfers in the 40Ca + 58,64Ni systems

Directory of Open Access Journals (Sweden)

Bourgin D.

2016-01-01

Full Text Available Fusion cross sections have been measured in the 40Ca + 58Ni and 40Ca + 64Ni systems at energies around and below the Coulomb barrier. The 40Ca beam was delivered by the XTU Tandem accelerator of the Laboratori Nazionali di Legnaro and evaporation residues were measured at very forward angles with the LNL electrostatic beam deflector. Coupled-channels calculations were performed which highlight possible strong effects of neutron transfers on the fusion below the barrier in the 40Ca + 64Ni system. Microscopic time-dependent Hartree-Fock calculations have also been performed for both systems. Preliminary results are shown.

Barriers to the use of mobile sales force automation systems: a salesperson’s perspective

OpenAIRE

Sinisalo, Jaakko; Karjaluoto, Heikki; Saraniemi, Saila

2015-01-01

Purpose – The purpose of this paper is to examine the barriers associated with the adoption and use of mobile sales force automation (SFA) systems from a salesperson’s perspective. Design/methodology/approach – A qualitative investigation of two business-to-business companies was conducted. Data collected from ten semi-structured interviews with directors or sales managers were analyzed to understand the main barriers to SFA system adoption. Findings – The study confirms the ex...

Effect of joint mechanism on vehicle redirectional capability of water-filled road safety barrier systems.

Science.gov (United States)

Thiyahuddin, M I; Thambiratnam, D P; Gu, Y T

2014-10-01

Portable water-filled barriers (PWFBs) are roadside appurtenances that prevent vehicles from penetrating into temporary construction zones on roadways. PWFBs are required to satisfy the strict regulations for vehicle re-direction in tests. However, many of the current PWFBs fail to re-direct the vehicle at high speeds due to the inability of the joints to provide appropriate stiffness. The joint mechanism hence plays a crucial role in the performance of a PWFB system at high speed impacts. This paper investigates the desired features of the joint mechanism in a PWFB system that can re-direct vehicles at high speeds, while limiting the lateral displacement to acceptable limits. A rectangular "wall" representative of a 30m long barrier system was modeled and a novel method of joining adjacent road barriers was introduced through appropriate pin-joint connections. The impact response of the barrier "wall" and the vehicle was obtained and the results show that a rotational stiffness of 3000kNm/rad at the joints seems to provide the desired features of the PWFB system to re-direct impacting vehicles and restrict the lateral deflection. These research findings will be useful to safety engineers and road barrier designers in developing a new generation of PWFBs for increased road safety. Copyright © 2014 Elsevier Ltd. All rights reserved.

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...

Towards a barrier height benchmark set for biologically relevant systems.

Science.gov (United States)

Kromann, Jimmy C; Christensen, Anders S; Cui, Qiang; Jensen, Jan H

2016-01-01

We have collected computed barrier heights and reaction energies (and associated model structures) for five enzymes from studies published by Himo and co-workers. Using this data, obtained at the B3LYP/6- 311+G(2d,2p)[LANL2DZ]//B3LYP/6-31G(d,p) level of theory, we then benchmark PM6, PM7, PM7-TS, and DFTB3 and discuss the influence of system size, bulk solvation, and geometry re-optimization on the error. The mean absolute differences (MADs) observed for these five enzyme model systems are similar to those observed for PM6 and PM7 for smaller systems (10-15 kcal/mol), while DFTB results in a MAD that is significantly lower (6 kcal/mol). The MADs for PMx and DFTB3 are each dominated by large errors for a single system and if the system is disregarded the MADs fall to 4-5 kcal/mol. Overall, results for the condensed phase are neither more or less accurate relative to B3LYP than those in the gas phase. With the exception of PM7-TS, the MAD for small and large structural models are very similar, with a maximum deviation of 3 kcal/mol for PM6. Geometry optimization with PM6 shows that for one system this method predicts a different mechanism compared to B3LYP/6-31G(d,p). For the remaining systems, geometry optimization of the large structural model increases the MAD relative to single points, by 2.5 and 1.8 kcal/mol for barriers and reaction energies. For the small structural model, the corresponding MADs decrease by 0.4 and 1.2 kcal/mol, respectively. However, despite these small changes, significant changes in the structures are observed for some systems, such as proton transfer and hydrogen bonding rearrangements. The paper represents the first step in the process of creating a benchmark set of barriers computed for systems that are relatively large and representative of enzymatic reactions, a considerable challenge for any one research group but possible through a concerted effort by the community. We end by outlining steps needed to expand and improve the data set

Cost of radon-barrier systems for uranium mill tailings

International Nuclear Information System (INIS)

Baker, E.G.; Hartley, J.N.

1982-08-01

This report deals specifically with the cost of three types of radon barrier systems, earthen covers, asphalt emulsion covers, and multilayer covers, which could meet standards proposed by the Environmental Protection Agency to stabilize uranium mill tailings located primarily in the western US. In addition, the report includes a sensitivity analysis of various factors which significantly effect the overall cost of the three systems. These analyses were based on a generic disposal site. Four different 3m thick earthen covers were tested and cost an average of $27/m 2 . The least expensive earthen cover cost was about $21/m 2 . The asphalt cover system (6 to 7 cm of asphalt topped with 0.6m of overburden) cost about $28/m 2 . The four multilayer covers averaged $57/m 2 , but materials handling problems encountered during the test inflated this cost above what was anticipated and significant cost reductions should be possible. The least expensive multilayer cover cost $43/m 2 . Based on the results of the Grand Junction field test we estimated the cost of covering the tailings from three high priority sites, Durango, Shiprock, and Salt Lake City (Vitro). The cost of a 3m earthen cover ranged from $18 to 33/m 2 for the seven disposal sites (two or three at each location) studied. The cost of asphalt cover systems were $23 to 28/m 2 and the multilayer cover costs were between $31 to 36/m 2 . The earthen cover costs are less than the Grand Junction field test cost primarily because cover material is available at or near most of the disposal sites selected. Earthen material was imported from 6 to 10 miles for the field test. Assuming more efficienct utilization of materials significantly reduced the cost of the multilayer covers

Understanding the modifiable health systems barriers to hypertension management in Malaysia: a multi-method health systems appraisal approach.

Science.gov (United States)

Risso-Gill, Isabelle; Balabanova, Dina; Majid, Fadhlina; Ng, Kien Keat; Yusoff, Khalid; Mustapha, Feisul; Kuhlbrandt, Charlotte; Nieuwlaat, Robby; Schwalm, J-D; McCready, Tara; Teo, Koon K; Yusuf, Salim; McKee, Martin

2015-07-03

The growing burden of non-communicable diseases in middle-income countries demands models of care that are appropriate to local contexts and acceptable to patients in order to be effective. We describe a multi-method health system appraisal to inform the design of an intervention that will be used in a cluster randomized controlled trial to improve hypertension control in Malaysia. A health systems appraisal was undertaken in the capital, Kuala Lumpur, and poorer-resourced rural sites in Peninsular Malaysia and Sabah. Building on two systematic reviews of barriers to hypertension control, a conceptual framework was developed that guided analysis of survey data, documentary review and semi-structured interviews with key informants, health professionals and patients. The analysis followed the patients as they move through the health system, exploring the main modifiable system-level barriers to effective hypertension management, and seeking to explain obstacles to improved access and health outcomes. The study highlighted the need for the proposed intervention to take account of how Malaysian patients seek treatment in both the public and private sectors, and from western and various traditional practitioners, with many patients choosing to seek care across different services. Patients typically choose private care if they can afford to, while others attend heavily subsidised public clinics. Public hypertension clinics are often overwhelmed by numbers of patients attending, so health workers have little time to engage effectively with patients. Treatment adherence is poor, with a widespread belief, stemming from concepts of traditional medicine, that hypertension is a transient disturbance rather than a permanent asymptomatic condition. Drug supplies can be erratic in rural areas. Hypertension awareness and education material are limited, and what exist are poorly developed and ineffective. Despite having a relatively well funded health system offering good access to

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

Manufacture and test of prototype water pipe chase barrier in ITER Magnet Feeder system

Energy Technology Data Exchange (ETDEWEB)

Lu, Kun, E-mail: lukun@ipp.ac.cn [Institute of Plasma Physics, Shushan Hu Road 350, Hefei, Anhui (China); Wen, Xinjie; Liu, Chen; Song, Yuntao [Institute of Plasma Physics, Shushan Hu Road 350, Hefei, Anhui (China); Niu, Erwu [ITER China, 15B Fuxing Road, Beijing 100862 (China); Gung, Chenyu; Su, Man [ITER Organization, Route de Vinon-sur-Verdon – CS 90046, 13067 St Paul-lez-Durance Cedex (France)

2016-11-01

The Magnet Feeder system in the International Thermonuclear Experimental Reactor (ITER) deploys electrical currents and supercritical helium to the superconducting magnets and the magnet diagnostic signals to the operators. In the current design, the feeders located in the upper L3 level of the Tokamak gallery penetrate the Tokamak coolant water system vault, the biological shield and the cryostat. As a secondary confinement to contain the activated coolant water in the vault in the case of water pipe burst accident, a water barrier is welded between the penetration in the water pipe chase outer wall and the mid-plane of the vacuum jacket of the Feeder Coil Terminal Box (CTB). A thin-wall stainless steel diaphragm with an omega shape profile is welded around the CTB as the water barrier to endure 2 bar hydraulic pressure. In addition, the barrier is designed as a flexible compensator to withstand a maximum of 15 mm of axial displacement of the CTB in case of helium leak accident without failure. This paper presents the detail configuration, the manufacturing and assembly processes of the water barrier. Test results of the prototype water barrier under simulated accident conditions are also reported. Successful qualification of the design and manufacturing process of the water barrier lays a good foundation for the series production of this subsystem.

Nurse-patient communication barriers in Iranian nursing.

Science.gov (United States)

Anoosheh, M; Zarkhah, S; Faghihzadeh, S; Vaismoradi, M

2009-06-01

Providing effective communication with patients is an essential aspect of nursing care. Understanding the barriers that inhibit nurse-patient communication can provide an opportunity to eliminate them. To investigate nurse-patient and environment-related communication barriers perceived by patients and nurses in Iranian nursing. A descriptive survey was carried out in three randomly selected educational hospitals in a large urban city in Iran. Data were collected by questionnaire; the study sample consisted of 61 patients and 75 nurses. Participants were asked to rate the importance of each communication barriers item. Finally, data were analysed using descriptive statistics, and to compare the perceived importance of communication barriers between patients and nurses, item means were calculated and the t-test for independent samples was applied. Similarities and differences between the two groups were identified. According to nurses' views, 'heavy nursing workload', 'hard nursing tasks' and 'lack of welfare facilities for nurses' were the main communication barriers. From patients' views, 'unfamiliarity of nurses with dialect', 'having contagious diseases' and 'sex differences between nurses and patients' were determined as the main communication barriers. The shared communication barriers were 'age difference', 'social class difference' and 'having contagious diseases'. It can be concluded that nursing managers and healthcare system planners should focus on eliminating or modifying the barriers stated by the two groups, particularly the shared ones. It is suggested that understanding the cultural aspects of nurse-patient communication barriers in various contexts can help nurses. The study relied on self-report by a limited sample of nurses and patients. The responses should now be tested by a larger sample and then by empirical research into actual practice in order to test whether the nurses' and patients' perceived ideas of communication barriers are

Engineered Barrier System Thermal-Hydraulic-Chemical Column Test Report

International Nuclear Information System (INIS)

W.E. Lowry

2001-01-01

The Engineered Barrier System (EBS) Thermal-Hydraulic-Chemical (THC) Column Tests provide data needed for model validation. The EBS Degradation, Flow, and Transport Process Modeling Report (PMR) will be based on supporting models for in-drift THC coupled processes, and the in-drift physical and chemical environment. These models describe the complex chemical interaction of EBS materials, including granular materials, with the thermal and hydrologic conditions that will be present in the repository emplacement drifts. Of particular interest are the coupled processes that result in mineral and salt dissolution/precipitation in the EBS environment. Test data are needed for thermal, hydrologic, and geochemical model validation and to support selection of introduced materials (CRWMS M and O 1999c). These column tests evaluated granular crushed tuff as potential invert ballast or backfill material, under accelerated thermal and hydrologic environments. The objectives of the THC column testing are to: (1) Characterize THC coupled processes that could affect performance of EBS components, particularly the magnitude of permeability reduction (increases or decreases), the nature of minerals produced, and chemical fractionation (i.e., concentrative separation of salts and minerals due to boiling-point elevation). (2) Generate data for validating THC predictive models that will support the EBS Degradation, Flow, and Transport PMR, Rev. 01

Barriers to Participation in Learning Management Systems in Saudi Arabian Universities

Directory of Open Access Journals (Sweden)

Abdullah Alenezi

2018-01-01

Full Text Available This study was designed to identify various barriers that have hindered the adoption of LMSs in Saudi Arabian universities. Learning management systems (LMSs have been adopted in many learning institutions because of their functionalities and applications to improve pedagogy. Universities have been encouraged to use LMSs to enhance the collaborative working environment among students and between the students and their instructors. This study was done by administering 150 questionnaires to students in three universities in Saudi Arabia. Findings from the study revealed that the main barriers to the use of LMSs were inadequate technical support by the universities, negative attitude toward technology, and inadequate training on the LMS platforms. Minor barriers identified include poor Internet access and networking, limited infrastructure to support the LMS, lack of hardware and software to run the LMS, and challenges in English language proficiency.

Computational Design and Experimental Validation of New Thermal Barrier Systems

Energy Technology Data Exchange (ETDEWEB)

Guo, Shengmin; Yang, Shizhong; Khosravi, Ebrahim

2011-12-31

This project (10/01/2010-9/30/2013), “Computational Design and Experimental Validation of New Thermal Barrier Systems”, originates from Louisiana State University (LSU) Mechanical Engineering Department and Southern University (SU) Department of Computer Science. This proposal will directly support the technical goals specified in DE-FOA-0000248, Topic Area 3: Turbine Materials, by addressing key technologies needed to enable the development of advanced turbines and turbine-based systems that will operate safely and efficiently using coal-derived synthesis gases. We will develop novel molecular dynamics method to improve the efficiency of simulation on novel TBC materials; we will perform high performance computing (HPC) on complex TBC structures to screen the most promising TBC compositions; we will perform material characterizations and oxidation/corrosion tests; and we will demonstrate our new Thermal barrier coating (TBC) systems experimentally under Integrated gasification combined cycle (IGCC) environments. The durability of the coating will be examined using the proposed High Temperature/High Pressure Durability Test Rig under real syngas product compositions.

Origin of Small Barriers in Jahn–Teller Systems

DEFF Research Database (Denmark)

Barriuso, M. T.; Ortiz-Sevilla, B.; Aramburu, J. A.

2013-01-01

. It is quantitatively proven that the elongated geometry observed for NaCl:Ni+ is due to the 3d–4s vibronic admixture, which is slightly larger than the anharmonicity in the eg JT mode that favors a compressed geometry. The existence of these two competing mechanisms explains the low value of B for the model system......Despite its relevance, the microscopic origin of the energy barrier, B, between the compressed and elongated geometries of Jahn–Teller (JT) systems is not well understood yet because of a lack of quantitative data about its various contributions. Seeking to clear up this matter, we have carried out...

Evaluation studies of EMA implementation’s barriers in business practice

Directory of Open Access Journals (Sweden)

Petra Mísařová

2010-01-01

Full Text Available Environmental Management Accounting (EMA is a system, which collects, records, evaluates and disseminates information about environmentally induced financial impacts and environmental impacts of the system itself. EMA is an important source of information for decision-making processes such as management of an organization, for EMS or environmental reporting. Identified barriers were included in the study which was conducted in three phases – in organizations espousing to Responsible Care, in selected companies with ISO 14000 and in companies with environmental management systems, validated by European EMAS. In early 2010 research was completed in the field of environmental management accounting and barriers defending the implemention of EMA to organization’s information system and the subsequent use of EMA. Primary data obtained from this study were subjected to cluster analysis and the results are presented in this scientific thesis. In practise there are many obstacles to full-fledged EMA implementation process into practice organization and its functioning. Findings of the study give answers to the question: „What barriers act as obstacles to the implementation of EMA into the practise of the organization and its functioning?“

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.

Facilitators and Barriers of Implementing a Measurement Feedback System in Public Youth Mental Health.

Science.gov (United States)

Kotte, Amelia; Hill, Kaitlin A; Mah, Albert C; Korathu-Larson, Priya A; Au, Janelle R; Izmirian, Sonia; Keir, Scott S; Nakamura, Brad J; Higa-McMillan, Charmaine K

2016-11-01

This study examines implementation facilitators and barriers of a statewide roll-out of a measurement feedback system (MFS) in a youth public mental health system. 76 % of all state care coordinators (N = 47) completed interviews, which were coded via content analysis until saturation. Facilitators (e.g., recognition of the MFS's clinical utility) and barriers (e.g., MFS's reliability and validity) emerged paralleling the Exploration, Adoption/Preparation, Implementation, and Sustainment framework outlined by Aarons et al. (Adm Policy Mental Health Mental Health Serv Res, 38:4-23, 2011). Sustainment efforts may leverage innovation fit, individual adopter, and system related facilitators.

Quantitative performance allocation of multi-barrier system for high-level radioactive waste disposal

International Nuclear Information System (INIS)

Ahn, Joon-Hong; Ikeda, Takao; Ohe, Toshiaki

1995-01-01

Performance assessment of each barrier consisting of geologic disposal system for high-level radioactive wastes is carried out quantitatively, and key radionuclides and parameters are pointed out. Chemical compositions and solubilities of radionuclides under repository conditions are determined by PHREEQE code staring from compositions of granitic groundwater observed in Japan. Glass dissolution analysis based on mass transfer theory and precipitation analysis have been done in order to determine the inner boundary condition for radionuclide diffusion through a bentonite-filled buffer region, where multi-member decay chain and isotopic sharing of solubility at the inner boundary are considered. Natural barrier is treated as homogeneous porous rock, or porous rock with infinite planar fractures. Performance of each barrier is evaluated in terms of non-dimensionalized hazard defined as the ratio of annual radioactivity release from each barrier to the annual limit on intake. At the outer edge of the engineered barriers, 239 Pu is the key unclide to the performance, whereas at the exit of the natural barrier, weakly-sorbing fission product nuclides such as 135 Cs, 129 I and 99 Tc dominate the hazard. (author) 50 refs

Safety indicators used to prove the role of natural barrier for Saligny near surface disposal system

International Nuclear Information System (INIS)

Niculae, Ortenzia; Durdun, I.; Ionita, Gh.

2007-01-01

Full text: The siting process for a near surface repository suitable for the radioactive waste resulted from Cernavoda NPP operation and decommissioning (low level radioactive waste with small amounts of long lived radionuclides) started in 1992 and it included the collection of data from specific field and laboratory works for each site selection stage as well as different safety performance evaluation. According to the IAEA standards (Safety Guide No.111-G-3.1, 1994), the purpose of the siting process is not to get the best solution but to find out 'an acceptable solution, with sufficient safety reserves'. Since 1996, detailed field and investigation works were performed in Saligny preferred site including an experimental area to test the improvement method proposed for the foundation ground of repository, as well as detailed performance assessments using specific computer codes. The paper presents the results of recent performance assessments for the natural barrier of disposal system. The calculations were done using HYDRUS 2D, FEHM and AMBER computer codes. The endpoint of the Safety Report for Siting a Near Surface Repository at Saligny Site [CITON and SCN, Safety Report for Siting a Near Surface Repository at Saligny Site, 2007, pages 8.2.1-1 to 8.2.1-22 and 8-63 to 8-70] was the assessment of safety indicators. Individual annual effective dose for exposed peoples (both workers and general public) was the main safety indicator. In the same document, the radionuclide concentration in the disposal system compartments has been evaluated, as supplementary safety indicator of repository barriers (especially to confirm the natural barrier performance). The results confirmed the performance of natural barrier: the maximum extension of H-3 and Co-60 contaminant plume after repository closure remains more above underground water level. In the aquifer, iodine concentration reaches a value of 10 -15 mol/l, at the same magnitude order with the admitted limit from CFR

Magnet system for a thermal barrier Tandem Mirror Reactor

International Nuclear Information System (INIS)

Kim, N.S.; Conn, R.W.

1981-01-01

The magnet system for a thermal barrier D-D tandem mirror reactor has been studied as part of the UCLA tandem mirror reactor design study SATYR. Three main considerations in designing the SATYR magnet system are to obtain the desired field strength variation throughout the system, to have proper space for plasma and neutron shielding, and to satisfy the MHD stability to achieve maximum central cell /beta/. Due to the importance and the complexity, the 'internal' field reversal magnet is the main concern in the entire magnet system for SATYR. Two different magnet designs, a non-uniform current density solenoid and a higher-order solenoid, are discussed. Coil levitation for the internal field reversal magnet has been analyzed

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

Towards a barrier height benchmark set for biologically relevant systems

Directory of Open Access Journals (Sweden)

Jimmy C. Kromann

2016-05-01

Full Text Available We have collected computed barrier heights and reaction energies (and associated model structures for five enzymes from studies published by Himo and co-workers. Using this data, obtained at the B3LYP/6- 311+G(2d,2p[LANL2DZ]//B3LYP/6-31G(d,p level of theory, we then benchmark PM6, PM7, PM7-TS, and DFTB3 and discuss the influence of system size, bulk solvation, and geometry re-optimization on the error. The mean absolute differences (MADs observed for these five enzyme model systems are similar to those observed for PM6 and PM7 for smaller systems (10–15 kcal/mol, while DFTB results in a MAD that is significantly lower (6 kcal/mol. The MADs for PMx and DFTB3 are each dominated by large errors for a single system and if the system is disregarded the MADs fall to 4–5 kcal/mol. Overall, results for the condensed phase are neither more or less accurate relative to B3LYP than those in the gas phase. With the exception of PM7-TS, the MAD for small and large structural models are very similar, with a maximum deviation of 3 kcal/mol for PM6. Geometry optimization with PM6 shows that for one system this method predicts a different mechanism compared to B3LYP/6-31G(d,p. For the remaining systems, geometry optimization of the large structural model increases the MAD relative to single points, by 2.5 and 1.8 kcal/mol for barriers and reaction energies. For the small structural model, the corresponding MADs decrease by 0.4 and 1.2 kcal/mol, respectively. However, despite these small changes, significant changes in the structures are observed for some systems, such as proton transfer and hydrogen bonding rearrangements. The paper represents the first step in the process of creating a benchmark set of barriers computed for systems that are relatively large and representative of enzymatic reactions, a considerable challenge for any one research group but possible through a concerted effort by the community. We end by outlining steps needed to expand and

Exploration of Scholars’ Attributions of Instructional Barriers in the Context of Pedagogical-Epistemological Belief Systems

Directory of Open Access Journals (Sweden)

Yılmaz SOYSAL

2017-08-01

Full Text Available In this study, two academics’ who have been employed in a private university teaching barriers and accompanied attributional reasoning were examined in the context of their belief systems with regards to learning, teaching and knowledge. This study was conducted with a basic qualitative perspective. By means of qualitative data gathering and analysis, it was aimed at estimating how the relation between teaching barriers and attributional reasoning was influenced by pedagogical-epistemological belief systems of scholars. Qualitative data was collected through two different semi-structured interview protocols and gathered data was analyzed with an inductive and interpretivist manner. The scholars’ beliefs systems’ divergences (teacher-centered vs. learner-centered allowed to explore the presumable relation of barrier-attribution in the context of pedagogical-epistemological belief systems. It was found out that the scholar who has adopted the more learner-centered modes of teaching favors more internally-oriented, controllable and non-stable attributional styles in illustrating her barrier-attribution relation. In contrast, it was also detected that the scholar who has held more teacher-centered teaching beliefs is liable to make attributions to overly external, non-controllable and stable factors in illuminating her barrier-attribution relation. Major outcomes of the study are evaluated by means of psychological (i.e., attribution theory and instructional (pedagogical-epistemological beliefs lenses and suggestions are offered in the context of higher education.

A path method for finding energy barriers and minimum energy paths in complex micromagnetic systems

International Nuclear Information System (INIS)

Dittrich, R.; Schrefl, T.; Suess, D.; Scholz, W.; Forster, H.; Fidler, J.

2002-01-01

Minimum energy paths and energy barriers are calculated for complex micromagnetic systems. The method is based on the nudged elastic band method and uses finite-element techniques to represent granular structures. The method was found to be robust and fast for both simple test problems as well as for large systems such as patterned granular media. The method is used to estimate the energy barriers in CoCr-based perpendicular recording media

Barriers to Participation in Tourism in the Disabled

Directory of Open Access Journals (Sweden)

Kaganek Krzysztof

2017-06-01

Full Text Available Introduction. Physical activity is critical to effective rehabilitation in people with disabilities and, consequently, is of high importance in their lives. However, participation of the disabled in physical activity, including tourism, is a much more complex issue than in the case in able-bodied individuals. Material and methods. This paper aims to fill the gap and familiarise the reader with barriers faced by the disabled who engage in tourism. The study group consisted of randomly selected 460 participants with certificates specifying the degree of their disability. The group included 55 (12% individuals with visual impairments, 203 (44.1% individuals with hearing impairments, and 202 (43.9% individuals with locomotor system disabilities. Results. The data derived from interviews made with people with physical dysfunctions, designed with a view to achieving the aims of the study, were used to develop logistic regression models. Conclusions. On average, the greatest and smallest numbers of barriers were reported by individuals with severe disabilities and those who had large families, respectively. Younger disabled people most often complained about the equipment barriers to participation in tourism. Older respondents were mostly challenged with social barriers. Of all the determinants analysed in the study, the perception of barriers to participation in tourism most often depended on the subjects’ degree of disability.

A Selection Method for COTS Systems

DEFF Research Database (Denmark)

Hedman, Jonas

new skills and methods supporting the process of evaluating and selecting information systems. This paper presents a method for selecting COTS systems. The method includes the following phases: problem framing, requirements and appraisal, and selection of systems. The idea and distinguishing feature...... behind the method is that improved understanding of organizational' ends' or goals should govern the selection of a COTS system. This can also be expressed as a match or fit between ‘ends' (e.g. improved organizational effectiveness) and ‘means' (e.g. implementing COTS systems). This way of approaching...

Modeling the Hydrogeochemical Transport of Radionuclides through Engineered Barriers System in the Proposed LLW Disposal Site of Taiwan - 12082

Energy Technology Data Exchange (ETDEWEB)

Lin, Wen-Sheng [Hydrotech Research Institute, National Taiwan University, Taipei, Taiwan (China); Liu, Chen-Wuing; Tsao, Jui-Hsuan [Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei, Taiwan (China); Li, Ming-Hsu [Institute of Hydrological and Oceanic Sciences, National Central University, Jhongli, Taiwan (China)

2012-07-01

A proposed site for final disposal of low-level radioactive waste located in Daren Township of Taitung County along the southeastern coast has been on the selected list in Taiwan. The geology of the Daren site consists of argillite and meta-sedimentary rocks. A mined cavern design with a tunnel system of 500 m below the surface is proposed. Concrete is used as the main confinement material for the engineered barrier. To investigate the hydrogeochemical transport of radionuclides through engineered barriers system, HYDROGEOCHEM5.0 model was applied to simulate the complex chemical interactions among radionuclides, the cement minerals of the concrete, groundwater flow, and transport in the proposed site. The simulation results showed that the engineered barriers system with the side ditch efficiently drained the ground water and lowered the concentration of the concrete degradation induced species (e.g., hydrogen ion, sulfate, and chloride). The velocity of groundwater observed at side ditch gradually decreased with time due to the fouling of pore space by the mineral formation of ettringite and thaumasite. The short half-life of Co-60, Sr-90 and Cs-137 significantly reduced the concentrations, whereas the long half-life of I-129(1.57x10{sup 7} years) and Am-241(432 years) remain stable concentrations at the interface of waste canister and concrete barrier after 300 years. The mineral saturation index (SI) was much less than zero due to the low aqueous concentration of radionuclide, so that the precipitation formation of Co-60, Sr-90, I-129, Cs-137 and Am-241 related minerals were not found. The effect of adsorption/desorption (i.e., surface complexation model) could be a crucial geochemical mechanism for the modeling of liquid-solid phase behavior of radionuclide in geochemically dynamic environments. Moreover, the development of advanced numerical models that are coupled with hydrogeochemical transport and dose assessment of radionuclide is required in the future

Numerical evaluation of energy barriers and magnetic relaxation in interacting nanostructured magnetic systems

International Nuclear Information System (INIS)

Chubykalo-Fesenko, Oksana A.; Chantrell, Roy W.

2004-01-01

We discuss a model to quantify long-time thermally induced magnetization reversal in magnetic systems with distributed properties. Two algorithms, based on kinetic and Metropolis Monte Carlo are introduced. While the former requires the constant recalculation of all energy barriers and is useful when the interactions are weak, the latter uses the Metropolis Monte Carlo to estimate the magnetization trajectory and, consequently, only the most probable transition rates are evaluated. The ridge optimization method is used to evaluate the energy barriers in a multidimensional energy landscape. The algorithms are applied to a granular system modeled by means of Voronoi polyhedra and having random in-plane anisotropy

The intestinal barrier in irritable bowel syndrome: subtype-specific effects of the systemic compartment in an in vitro model.

Directory of Open Access Journals (Sweden)

Samefko Ludidi

Full Text Available Irritable bowel syndrome (IBS is a disorder with multifactorial pathophysiology. Intestinal barrier may be altered, especially in diarrhea-predominant IBS (IBS-D. Several mediators may contribute to increased intestinal permeability in IBS.We aimed to assess effects of tryptase and LPS on in vitro permeability using a 3-dimensional cell model after basolateral cell exposure. Furthermore, we assessed the extent to which these mediators in IBS plasma play a role in intestinal barrier function.Caco-2 cells were grown in extracellular matrix to develop into polarized spheroids and were exposed to tryptase (10 - 50 mU, LPS (1 - 50 ng/mL and two-fold diluted plasma samples of 7 patients with IBS-D, 7 with constipation-predominant IBS (IBS-C and 7 healthy controls (HC. Barrier function was assessed by the flux of FITC-dextran (FD4 using live cell imaging. Furthermore, plasma tryptase and LPS were determined.Tryptase (20 and 50 mU and LPS (6.25 - 50 ng/mL significantly increased Caco-2 permeability versus control (all P< 0.05. Plasma of IBS-D only showed significantly elevated median tryptase concentrations (7.1 [3.9 - 11.0] vs. 4.2 [2.2 - 7.0] vs. 4.2 [2.5 - 5.9] μg/mL; P<0.05 and LPS concentrations (3.65 [3.00 - 6.10] vs. 3.10 [2.60-3.80] vs. 2.65 [2.40 - 3.40] EU/ml; P< 0.05 vs. IBS-C and HC. Also, plasma of IBS-D increased Caco-2 permeability versus HC (0.14450 ± 0.00472 vs. 0.00021 ± 0.00003; P < 0.001, which was attenuated by selective inhibition of tryptase and LPS (P< 0.05.Basolateral exposure of spheroids to plasma of IBS-D patients resulted in a significantly increased FD4 permeation, which was partially abolished by selective inhibition of tryptase and LPS. These findings point to a role of systemic tryptase and LPS in the epithelial barrier alterations observed in patients with IBS-D.

Value engineering study for seletion of verticle barrier technology at a Superfund site

International Nuclear Information System (INIS)

Bryan, E.E.; Guglielmetti, J.L.; Butler, P.B.; Brill, M.P.

1997-01-01

A value engineering (VE) study was conducted to identify and evaluate vertical barrier technologies and alignments for a Superfund project in New Castle County, Delaware. The objective was to select and recommend the most appropriate vertical barrier(s) for two separate landfills and a portion of the manufacturing plant on the site. A VE team was assembled to identify and evaluate site specific issues related to effectiveness, constructability and cost for numerous vertical barrier technologies. Several cost-effective alternatives were identified that met project objectives. The VE study concluded that a composite vertical barrier system consisting of a soil-bentonite slurry trench and steel sheet piles would provide effective containment of the North Landfill. Additionally, the geologic confining unit specified in the Record of Decision (ROD) was found to be unsuitable as a vertical barrier key and a more suitable, shallow confining unit was discovered. This paper describes the value engineering process and results of the VE study for one of the landfills

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.

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

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

Combined photovoltaic and solar-thermal systems: overcoming barriers to market acceptance. Paper no. IGEC-1-136

International Nuclear Information System (INIS)

Collins, M.R.

2005-01-01

In 1997, the International Energy Association's (IEA) Photovoltaic Power Systems Program (PVSP) initiated IEA Task 7 to evaluate the technical status of combined Photovoltaic and Solar-Thermal systems (PV/T), and to formulate a roadmap for future development. Because the Task was initiated by the PVSP, however, individuals from the Solar Heating and Cooling Program (SHCP) were not invited to participate, and the Task Group lacked any significant expertise with solar-thermal systems. When the Task submitted its final report in 2002, it consisted of an accounting of existing systems and a list of the perceived market barriers. Without input from the SHCP, however, no move could be made to actually address those barriers. IEA Task 7, however, did recognize that the participation of the SHCP was needed, and in 1999 made an effort to initiate some discussion between the PVSP and the SHCP. The result was IEA Task 35 - PV/T Systems, which met for the first time in January of 2005. The new group intends to reevaluate the findings of Task 7, and to develop the means by which these market barriers can be overcome. The current discussion will provide an overview of existing and potential PV/T systems and their technical status. Further, it will report on the methodology established by the Task 35 work group to overcome the aforementioned market barriers. (author)

Barriers to installing innovative energy systems in existing housing stock identified

NARCIS (Netherlands)

Hoppe, Thomas

2013-01-01

Several barriers to upgrading existing social housing with innovative energy systems (IES) have been identified by a study of eight large-scale renovation projects in the Netherlands. These include a lack of trust between stakeholders, opposition from tenants on grounds of increased costs or delays,

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

Assessment on mechanical effect of engineering barrier system to fault movement. Research document

International Nuclear Information System (INIS)

Hirai, Takashi; Tanai, Kenji; Takaji, Kazuhiko; Ohnuma, Satoshi

2003-03-01

The objective of this report is to clarify mechanical effect of engineering barrier system to the unavoidable fault movement. From the basic policy of the second progress report by JNC, natural phenomenon which affect strongly to the geological disposal system should be avoided. However, small faults as sliprate ''C'' far from principal fault zone, are difficult to be found out completely. Therefore, it is important to evaluate the influence of these fault movements and to clarify stability and safety of the engineered barrier system. Accordingly, the effect of a rock displacement across a deposition holl was considered and the midium scale test was carried out. Then midium scale test was simulated by Finit Element Method in which the constitutive model of Tresca was adopted to analyze elastoplastic behavior of buffer material. From the result of the midium scale test and the analysis, it was realized that the buffer material diminish shear stress acting on the overpack. Further analytical study was conducted to evaluate the real scale engineered barrier system designed in the second progress report by JNC. From the study, it was appeared that stress in buffer corresponded to the stress calculated for the midium scale test model. Consequently, it was obvious that rock displacement, 80% of buffer didn't affect overpack if velocity of fault movement was under 10 cm/sec. (author)

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

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.

An in vitro and in vivo study of peptide-functionalized nanoparticles for brain targeting : The importance of selective blood–brain barrier uptake

NARCIS (Netherlands)

Bode, Gerard H.; Coué, G.M.J.P.C.; Freese, Christian; Pickl, Karin E.; Sanchez-Purrà, Maria; Albaiges, Berta; Borrós, Salvador; van Winden, Ewoud C.; Tziveleka, Leto Aikaterini; Sideratou, Zili; Engbersen, Johan F.J.; Singh, Smriti; Albrecht, Krystyna; Groll, Jürgen; Möller, Martin; Pötgens, Andy J.G.; Schmitz, Christoph; Fröhlich, Eleonore; Grandfils, Christian; Sinner, Frank M.; Kirkpatrick, C. James; Steinbusch, Harry W.M.; Frank, Hans Georg; Unger, Ronald E.; Martinez-Martinez, Pilar

2017-01-01

Targeted delivery of drugs across endothelial barriers remains a formidable challenge, especially in the case of the brain, where the blood–brain barrier severely limits entry of drugs into the central nervous system. Nanoparticle-mediated transport of peptide/protein-based drugs across endothelial

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...

Time evolution of the Clay Barrier Chemistry in a HLW deep geological disposal in granite

International Nuclear Information System (INIS)

Font, I.; Miguel, M. J.; Juncosa, R.

2000-01-01

The main goal of a high level waste geological disposal is to guarantee the waste isolation from the biosphere, locking them away into very deep geological formations. The best way to assure the isolation is by means of a multiple barrier system. These barriers, in a serial disposition, should assure the confinement function of the disposal system. Two kinds of barriers are considered: natural barriers (geological formations) and engineered barriers (waste form, container and backfilling and sealing materials). Bentonite is selected as backfilling and sealing materials for HLW disposal into granite formations, due to its very low permeability and its ability to fill the remaining spaces. bentonite has also other interesting properties, such as, the radionuclide retention capacity by sorption processes. Once the clay barrier has been placed, the saturation process starts. The granite groundwater fills up the voids of the bentonite and because of the chemical interactions, the groundwater chemical composition varies. Near field processes, such as canister corrosion, waste leaching and radionuclide release, strongly depends on the water chemical composition. Bentonite pore water composition is such a very important feature of the disposal system and its determination and its evolution have great relevance in the HLW deep geological disposal performance assessment. The process used for the determination of the clay barrier pore water chemistry temporal evolution, and its influence on the performance assessment, are presented in this paper. (Author)

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

Microstructure Evolution and Durability of Advanced Environmental Barrier Coating Systems for SiC/SiC Ceramic Matrix Composites

Science.gov (United States)

Zhu, Dongming; Evans, Laura J.; McCue, Terry R.; Harder, Bryan

2016-01-01

Environmental barrier coated SiC-SiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures with improved efficiency, reduce engine weight and cooling requirements. Advanced HfO2 and rare earth silicate environmental barrier coatings (EBCs), along with multicomponent hafnium and rare earth silicide EBC bond coats have been developed. The coating degradation mechanisms in the laboratory simulated engine thermal cycling, and fatigue-creep operating environments are also being investigated. This paper will focus on the microstructural and compositional evolutions of an advanced environmental barrier coating system on a SiC-SiC CMC substrate during the high temperature simulated durability tests, by using a Field Emission Gun Scanning Electron Microscopy, Energy Dispersive Spectroscopy (EDS) and Wavelength Dispersive Spectroscopy (WDS). The effects of Calcium-Magnesium-Alumino-Silicate (CMAS) from road sand or volcano-ash deposits on the degradation mechanisms of the environmental barrier coating systems will also be discussed. The detailed analysis results help understand the EBC-CMC system performance, aiming at the durability improvements to achieve more robust, prime-reliant environmental barrier coatings.

Fission Meter Information Barrier Attribute Measurement System: Task 1 Report: Document existing Fission Meter neutron IB system

Energy Technology Data Exchange (ETDEWEB)

Kerr, P. L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-02-28

An SNM attribute Information Barrier (IB) system was developed for a 2011 US/UK Exercise. The system was modified and extensively tested in a 2013-2014 US-UK Measurement Campaign. This work demonstrated rapid deployment of an IB system for potential treaty use. The system utilizes an Ortec Fission Meter neutron multiplicity counter and custom computer code. The system demonstrates a proof-of-principle automated Pu-240 mass determination with an information barrier. After a software start command is issued, the system automatically acquires and downloads data, performs an analysis, and displays the results. This system conveys the results of a Pu mass threshold measurements in a way the does not reveal sensitive information. In full IB mode, only red/green ‘lights’ are displayed in the software. In test mode, more detailed information is displayed. The code can also read in, analyze, and display results from previously acquired or simulated data. Because the equipment is commercial-off-the-shelf (COTS), the system demonstrates a low-cost short-lead-time technology for treaty SNM attribute measurements. A deployed system will likely require integration of additional authentication and tamper-indicating technologies. This will be discussed for the project in this and future progress reports.

Biomechanics of the transport barrier in the nuclear pore complex.

Science.gov (United States)

Stanley, George J; Fassati, Ariberto; Hoogenboom, Bart W

2017-08-01

The nuclear pore complex (NPC) is the selective gateway through which all molecules must pass when entering or exiting the nucleus. It is a cog in the gene expression pathway, an entrance to the nucleus exploited by viruses, and a highly-tuned nanoscale filter. The NPC is a large proteinaceous assembly with a central lumen occluded by natively disordered proteins, known as FG-nucleoporins (or FG-nups). These FG-nups, along with a family of soluble proteins known as nuclear transport receptors (NTRs), form the selective transport barrier. Although much is known about the transport cycle and the necessity of NTRs for chaperoning cargo molecules through the NPC, the mechanism by which NTRs and NTR•cargo complexes translocate the selective transport barrier is not well understood. How can disordered FG-nups and soluble NTRs form a transport barrier that is selective, ATP-free, and fast? In this work, we review various mechanical approaches - both experimental and theoretical/computational - employed to better understand the morphology of the FG-nups, and their role in nucleocytoplasmic transport. Recent experiments on FG-nups tethered to planar surfaces, coupled with quantitative modelling work suggests that FG-nup morphologies are the result of a finely balanced system with significant contributions from FG-nup cohesiveness and entropic repulsion, and from NTR•FG-nup binding avidity; whilst AFM experiments on intact NPCs suggest that the FG-nups are sufficiently cohesive to form condensates in the centre of the NPC lumen, which may transiently dissolve to facilitate the transport of larger cargoes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design of barrier bucket kicker control system

Science.gov (United States)

Ni, Fa-Fu; Wang, Yan-Yu; Yin, Jun; Zhou, De-Tai; Shen, Guo-Dong; Zheng, Yang-De.; Zhang, Jian-Chuan; Yin, Jia; Bai, Xiao; Ma, Xiao-Li

2018-05-01

The Heavy-Ion Research Facility in Lanzhou (HIRFL) contains two synchrotrons: the main cooler storage ring (CSRm) and the experimental cooler storage ring (CSRe). Beams are extracted from CSRm, and injected into CSRe. To apply the Barrier Bucket (BB) method on the CSRe beam accumulation, a new BB technology based kicker control system was designed and implemented. The controller of the system is implemented using an Advanced Reduced Instruction Set Computer (RISC) Machine (ARM) chip and a field-programmable gate array (FPGA) chip. Within the architecture, ARM is responsible for data presetting and floating number arithmetic processing. The FPGA computes the RF phase point of the two rings and offers more accurate control of the time delay. An online preliminary experiment on HIRFL was also designed to verify the functionalities of the control system. The result shows that the reference trigger point of two different sinusoidal RF signals for an arbitrary phase point was acquired with a matched phase error below 1° (approximately 2.1 ns), and the step delay time better than 2 ns were realized.

Seismic evidence for the preservation of several stacked Pleistocene coastal barrier/lagoon systems on the Gulf of Valencia continental shelf (western Mediterranean)

Science.gov (United States)

Albarracín, Silvia; Alcántara-Carrió, Javier; Barranco, Andrés; Sánchez García, María José; Fontán Bouzas, Ángela; Rey Salgado, Jorge

2013-04-01

The focus of this study is the analysis of coastal sand barriers and associated coastal lagoons on the inner continental shelf of the Gulf of Valencia (western Mediterranean), based on two W-E seismic profiles recorded seaward of the Albufera de Valencia coastal lagoon. Seismic facies identified include a number of coastal sand barriers with landward lagoons draped by contemporary continental shelf deposits. The barrier systems have been grouped into two sedimentary systems tracts, the older one corresponding to a prograding/aggrading highstand systems tract involving at least four paleo-coastal sand barrier/lagoon systems, followed landward by a transgressive systems tract comprising three such systems. All the systems have been allocated a Tyrrhenian age, the formation of individual barrier systems having been associated with successive sea-level stillstands, and their present-day position being explained by the very high regional subsidence rate. In summary, this study demonstrates that the Quaternary stratigraphic record of the Gulf of Valencia inner continental shelf is composed of littoral sand facies, in particular coastal sand barrier and lagoon deposits. These findings are in agreement with corresponding observations on other continental shelves of the western Mediterranean, showing that the formation of coastal sand barriers was a characteristic feature of this region during the Quaternary.

Today's Yucca mountain project and a new concept of multi-barrier system

International Nuclear Information System (INIS)

Xu Guoqing

2008-01-01

This paper mainly deals with the current status of Yucca Mountain project and the progress in study on engineering barrier in Belgium and introduces the future plan for Yucca Mountain project, two reports on draft supplemental environmental impact statement, and the view of New York Sen. Hillary Clinton and Illinois Sen. Barack Obama during the 2008 president elections related to the building a nuclear waste repository in Nevada. In order to enhance the security of geological disposal of high-level radioactive waste, a new concept about multi-barrier system is given by Belgium and is concisely described here. (authors)

Reactive Transport and Coupled THM Processes in Engineering Barrier Systems (EBS)

International Nuclear Information System (INIS)

Steefel, Carl; Rutqvist, Jonny; Tsang, Chin-Fu; Liu, Hui-Hai; Sonnenthal, Eric; Houseworth, Jim; Birkholzer, Jens

2010-01-01

Geological repositories for disposal of high-level nuclear wastes generally rely on a multi-barrier system to isolate radioactive wastes from the biosphere. The multi-barrier system typically consists of a natural barrier system, including repository host rock and its surrounding subsurface environment, and an engineering barrier system (EBS). EBS represents the man-made, engineered materials placed within a repository, including the waste form, waste canisters, buffer materials, backfill and seals (OECD, 2003). EBS plays a significant role in the containment and long-term retardation of radionuclide release. EBS is involved in complex thermal, hydrogeological, mechanical, chemical and biological processes, such as heat release due to radionuclide decay, multiphase flow (including gas release due to canister corrosion), swelling of buffer materials, radionuclide diffusive transport, waste dissolution and chemical reactions. All these processes are related to each other. An in-depth understanding of these coupled processes is critical for the performance assessment (PA) for EBS and the entire repository. Within the EBS group of Used Fuel Disposition (UFD) Campaign, LBNL is currently focused on (1) thermal-hydraulic-mechanical-chemical (THMC) processes in buffer materials (bentonite) and (2) diffusive transport in EBS associated with clay host rock, with a long-term goal to develop a full understanding of (and needed modeling capabilities to simulate) impacts of coupled processes on radionuclide transport in different components of EBS, as well as the interaction between near-field host rock (e.g., clay) and EBS and how they effect radionuclide release. This final report documents the progress that LBNL has made in its focus areas. Specifically, Section 2 summarizes progress on literature review for THMC processes and reactive-diffusive radionuclide transport in bentonite. The literature review provides a picture of the state-of-the-art of the relevant research areas

Reactive Transport and Coupled THM Processes in Engineering Barrier Systems (EBS)

Energy Technology Data Exchange (ETDEWEB)

Steefel, Carl; Rutqvist, Jonny; Tsang, Chin-Fu; Liu, Hui-Hai; Sonnenthal, Eric; Houseworth, Jim; Birkholzer, Jens

2010-08-31

Geological repositories for disposal of high-level nuclear wastes generally rely on a multi-barrier system to isolate radioactive wastes from the biosphere. The multi-barrier system typically consists of a natural barrier system, including repository host rock and its surrounding subsurface environment, and an engineering barrier system (EBS). EBS represents the man-made, engineered materials placed within a repository, including the waste form, waste canisters, buffer materials, backfill and seals (OECD, 2003). EBS plays a significant role in the containment and long-term retardation of radionuclide release. EBS is involved in complex thermal, hydrogeological, mechanical, chemical and biological processes, such as heat release due to radionuclide decay, multiphase flow (including gas release due to canister corrosion), swelling of buffer materials, radionuclide diffusive transport, waste dissolution and chemical reactions. All these processes are related to each other. An in-depth understanding of these coupled processes is critical for the performance assessment (PA) for EBS and the entire repository. Within the EBS group of Used Fuel Disposition (UFD) Campaign, LBNL is currently focused on (1) thermal-hydraulic-mechanical-chemical (THMC) processes in buffer materials (bentonite) and (2) diffusive transport in EBS associated with clay host rock, with a long-term goal to develop a full understanding of (and needed modeling capabilities to simulate) impacts of coupled processes on radionuclide transport in different components of EBS, as well as the interaction between near-field host rock (e.g., clay) and EBS and how they effect radionuclide release. This final report documents the progress that LBNL has made in its focus areas. Specifically, Section 2 summarizes progress on literature review for THMC processes and reactive-diffusive radionuclide transport in bentonite. The literature review provides a picture of the state-of-the-art of the relevant research areas

Scientific investigation plan for initial engineered barrier system field tests

International Nuclear Information System (INIS)

Wunan Lin.

1993-02-01

The purpose of this Scientific Investigation Plan (SIP) is to describe tests known as Initial Engineered Barrier System Field Tests (IEBSFT) and identified by Work Breakdown Structure as WBS 1.2.2.2.4. The IEBSFT are precursors to the Engineered Barrier System Field Test (EBSFT), WBS 1.2.2.2.4, to be conducted in the Exploratory Study Facility (ESF) at Yucca Mountain. The EBSFT and IEBSFT are designed to provide information on the interaction between waste packages (simulated by heated containers) and the surrounding rock mass, its vadose water, and infiltrated water. Heater assemblies will be installed in drifts or boreholes openings and heated to measure moisture movement during heat-up and subsequent cool-down of the rock mass. In some of the tests, infiltration of water into the heated rock mass will be studied. Throughout the heating and cooling cycle, instruments installed in the rock will monitor such parameters as temperature, moisture content, concentration of some chemical species, and stress and strain. Rock permeability measurements, rock and fluid (water and gas) sampling, and fracture pattern measurements will also be made before and after the test

Pharmacists' Attitudes and Perceived Barriers to Human Papillomavirus (HPV) Vaccination Services.

Science.gov (United States)

Hastings, Tessa J; Hohmann, Lindsey A; McFarland, Stuart J; Teeter, Benjamin S; Westrick, Salisa C

2017-08-07

Use of non-traditional settings such as community pharmacies has been suggested to increase human papillomavirus (HPV) vaccination uptake and completion rates. The objectives of this study were to explore HPV vaccination services and strategies employed by pharmacies to increase HPV vaccine uptake, pharmacists' attitudes towards the HPV vaccine, and pharmacists' perceived barriers to providing HPV vaccination services in community pharmacies. A pre-piloted mail survey was sent to 350 randomly selected community pharmacies in Alabama in 2014. Measures included types of vaccines administered and marketing/recommendation strategies, pharmacists' attitudes towards the HPV vaccine, and perceived system and parental barriers. Data analysis largely took the form of descriptive statistics. 154 pharmacists completed the survey (response rate = 44%). The majority believed vaccination is the best protection against cervical cancer (85.3%), HPV is a serious threat to health for girls (78.8%) and boys (55.6%), and children should not wait until they are sexually active to be vaccinated (80.1%). Perceived system barriers included insufficient patient demand (56.5%), insurance plans not covering vaccination cost (54.8%), and vaccine expiration before use (54.1%). Respondents also perceived parents to have inadequate education and understanding about HPV infection (86.6%) and vaccine safety (78.7%). Pharmacists have positive perceptions regarding the HPV vaccine. Barriers related to system factors and perceived parental concerns must be overcome to increase pharmacist involvement in HPV vaccinations.

The disposal of Canada's nuclear fuel waste: engineered barriers alternatives

International Nuclear Information System (INIS)

Johnson, L.H.; Tait, J.C.; Shoesmith, D.W.; Crosthwaite, J.L.; Gray, M.N.

1994-01-01

The concept for disposal of Canada's nuclear fuel waste involves emplacing the waste in a vault excavated at a depth of 500 to 1000 m in plutonic rock of the Canadian Shield. The solid waste would be isolated from the biosphere by a multibarrier system consisting of engineered barriers, including long-lived containers and clay and cement-based sealing materials, and the natural barrier provided by the massive geological formation. The technical feasibility of this concept and its impact on the environment and human health are being documented in an Environmental Impact Statement (EIS), which will be submitted for review under the federal Environmental Assessment and Review Process. This report, one of nine EIS primary references, describes the various alternative designs and materials for engineered barriers that have been considered during the development of the Canadian disposal concept and summarizes engineered barrier concepts being evaluated in other countries. The basis for the selection of a reference engineered barrier system for the EIS is presented. This reference system involves placing used CANDU (Canada Deuterium Uranium) fuel bundles in titanium containers, which would then be emplaced in boreholes drilled in the floor of disposal rooms. Clay-based sealing materials would be used to fill both the space between the containers and the rock and the remaining excavations. In the section on waste forms, the properties of both used-fuel bundles and solidified high-level wastes, which would be produced by treating wastes resulting from the reprocessing of used fuel, are discussed. Methods of solidifying the wastes and the chemical durability of the solidified waste under disposal conditions are reviewed. Various alternative container designs are reviewed, ranging from preliminary conceptual designs to designs that have received extensive prototype testing. Results of structural performance, welding and inspection studies are also summarized. The corrosion of

Nagra technical report 14-03, characteristic dosage intervals and documentation for the assessment of barrier systems

International Nuclear Information System (INIS)

2014-12-01

This comprehensive technical report published by the Swiss National Cooperative for the Disposal of Radioactive Wastes Nagra discusses the procedure for selecting sites for deep geological repositories for all categories of radioactive waste produced in Switzerland, as defined in the conceptual part of the Sectoral Plan for Deep Geological Repositories (BFE 2008). Analyses are presented and discussed that determine the priority host rocks for the disposal of low, intermediate and high level radioactive wastes. The evaluation of the effectiveness of the barrier systems is discussed. Also, analyses are presented and discussed in connection with the regions where sites for the repositories may be located. Important site-specific geological information is examined which is to be used in the assessment of possible repository sites from the safety analysis point of view

The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities In Assessing The Degradation Of Cementitious Barriers

Energy Technology Data Exchange (ETDEWEB)

Flach, G. P. [Savannah River Site (SRS), Aiken, SC (United States); Burns, H. H. [Savannah River Site (SRS), Aiken, SC (United States); Langton, C. [Savannah River Site (SRS), Aiken, SC (United States); Smith, F. G. III [Savannah River Site (SRS), Aiken, SC (United States); Brown, K. G. [Vanderbilt University, Nashville, TN (United States); Kosson, D. S. [Vanderbilt University, Nashville, TN (United States); Garrabrants, A. C. [Vanderbilt University, Nashville, TN (United States); Sarkar, S. [Vanderbilt University, Nashville, TN (United States); van der Sloot, H. [Hans van der Sloot Consultancy (The Netherlands); Meeussen, J. C.L. [Nuclear Research and Consultancy Group, Petten (The Netherlands); Samson, E. [SIMCO Technologies Inc. , 1400, boul. du Parc - Technologique , Suite 203, Quebec (Canada); Mallick, P. [United States Department of Energy, 1000 Independence Ave. SW , Washington, DC (United States); Suttora, L. [United States Department of Energy, 1000 Independence Ave. SW , Washington, DC (United States); Esh, D. W. [U .S. Nuclear Regulatory Commission , Washington, DC (United States); Fuhrmann, M. J. [U .S. Nuclear Regulatory Commission , Washington, DC (United States); Philip, J. [U .S. Nuclear Regulatory Commission , Washington, DC (United States)

2013-01-11

The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste and Nuclear Materials Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to 100 years and longer for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox has produced tangible benefits to the DOE Performance Assessment (PA) community. A review of prior DOE PAs has provided a list of potential opportunities for improving cementitious barrier performance predictions through the use of the CBP software tools. These opportunities include: 1) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, 2) prediction of changes in Kd/mobility as a function of time that result from changing pH and redox conditions, 3) concrete degradation from rebar corrosion due to carbonation, 4) early age cracking from drying and/or thermal shrinkage and 5) degradation due to sulfate attack. The CBP has already had opportunity to provide near-term, tangible support to ongoing DOE-EM PAs such as the Savannah River Saltstone Disposal Facility (SDF) by providing a sulfate attack analysis that predicts the extent and damage that sulfate ingress will have on the concrete vaults over extended time (i.e., > 1000 years). This analysis is one of the many technical opportunities in cementitious barrier performance that can be addressed by the DOE-EM sponsored CBP software

Barrier and operational risk analysis of hydrocarbon releases (BORA-Release)

International Nuclear Information System (INIS)

Sklet, Snorre; Vinnem, Jan Erik; Aven, Terje

2006-01-01

This paper presents results from a case study carried out on an offshore oil and gas production platform with the purpose to apply and test BORA-Release, a method for barrier and operational risk analysis of hydrocarbon releases. A description of the BORA-Release method is given in Part I of the paper. BORA-Release is applied to express the platform specific hydrocarbon release frequencies for three release scenarios for selected systems and activities on the platform. The case study demonstrated that the BORA-Release method is a useful tool for analysing the effect on the release frequency of safety barriers introduced to prevent hydrocarbon releases, and to study the effect on the barrier performance of platform specific conditions of technical, human, operational, and organisational risk influencing factors (RIFs). BORA-Release may also be used to analyse the effect on the release frequency of risk reducing measures

PILOT-SCALE EVALUATION OF ENGINEERED BARRIER SYSTEMS FOR THE YUCCA MOUNTAIN PROJECT

International Nuclear Information System (INIS)

Webb, S.W.; George, J.T.; Finley, R.E.

2001-01-01

This paper describes two quarter-scale experiments (1.4 m diameter) and associated numerical analyses on granular backfill engineered barrier systems in support of the Yucca Mountain Project for the potential repository. The two configurations include a sloped capillary barrier and a plain backfill. The tests involve application of dyed water as a constant line infiltration source along the top of the test set-up, monitoring water movement through the test, and measuring water exiting the experiments. A complete water balance estimate is made for each test, and observed water movement is compared with (1) detailed numerical analyses conducted using the TOUGH2 code for unsaturated flow in porous media and (2) posttest observations. The results of the testing and analyses show that for the injection rates and configuration applied, the capillary barrier design diverts a significant amount of all injected water and the TOUGH2 pretest predictions show qualitative and quantitative agreement with the experimental data

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

Response of a thermal barrier system to acoustic excitation in a gas turbine nuclear reactor

International Nuclear Information System (INIS)

Betts, W.S. Jr.; Blevins, R.D.

1980-11-01

A gas turbine located within a High-Temperature Gas-Cooled Reactor (HTGR) induces high acoustic sound pressure levels into the primary coolant (helium). This acoustic loading induces high cycle fatigue stresses which may control the design of the thermal barrier system. This study examines the dynamic response of a thermal barrier configuration consisting of a fibrous insulation compressed against the reactor vessel by a coverplate which is held in position by a central attachment fixture. The results of dynamic vibration analyses indicate the effect of the plate size and curvature and the attachment size on the response of the thermal barrier

Astrocytic TYMP and VEGFA drive blood-brain barrier opening in inflammatory central nervous system lesions.

Science.gov (United States)

Chapouly, Candice; Tadesse Argaw, Azeb; Horng, Sam; Castro, Kamilah; Zhang, Jingya; Asp, Linnea; Loo, Hannah; Laitman, Benjamin M; Mariani, John N; Straus Farber, Rebecca; Zaslavsky, Elena; Nudelman, German; Raine, Cedric S; John, Gareth R

2015-06-01

In inflammatory central nervous system conditions such as multiple sclerosis, breakdown of the blood-brain barrier is a key event in lesion pathogenesis, predisposing to oedema, excitotoxicity, and ingress of plasma proteins and inflammatory cells. Recently, we showed that reactive astrocytes drive blood-brain barrier opening, via production of vascular endothelial growth factor A (VEGFA). Here, we now identify thymidine phosphorylase (TYMP; previously known as endothelial cell growth factor 1, ECGF1) as a second key astrocyte-derived permeability factor, which interacts with VEGFA to induce blood-brain barrier disruption. The two are co-induced NFκB1-dependently in human astrocytes by the cytokine interleukin 1 beta (IL1B), and inactivation of Vegfa in vivo potentiates TYMP induction. In human central nervous system microvascular endothelial cells, VEGFA and the TYMP product 2-deoxy-d-ribose cooperatively repress tight junction proteins, driving permeability. Notably, this response represents part of a wider pattern of endothelial plasticity: 2-deoxy-d-ribose and VEGFA produce transcriptional programs encompassing angiogenic and permeability genes, and together regulate a third unique cohort. Functionally, each promotes proliferation and viability, and they cooperatively drive motility and angiogenesis. Importantly, introduction of either into mouse cortex promotes blood-brain barrier breakdown, and together they induce severe barrier disruption. In the multiple sclerosis model experimental autoimmune encephalitis, TYMP and VEGFA co-localize to reactive astrocytes, and correlate with blood-brain barrier permeability. Critically, blockade of either reduces neurologic deficit, blood-brain barrier disruption and pathology, and inhibiting both in combination enhances tissue preservation. Suggesting importance in human disease, TYMP and VEGFA both localize to reactive astrocytes in multiple sclerosis lesion samples. Collectively, these data identify TYMP as an

Selected aspects of fusion reactions

International Nuclear Information System (INIS)

Lacroix, D.

2003-01-01

In this lecture, we present selected aspects of nuclear fusion. The importance of the initial geometry of the reaction and its relation to fusion barrier are first discussed. The effect of deformation leading to the notion of barrier distribution is then illustrated. After a brief overview of the advantages of macroscopic theories, the dynamics of nuclear system under large amplitude motion is reviewed. The di-nuclear concept is presented to understand the competition between fusion and quasi-fission. This concept is then generalized to account for the dissipative dynamics in multidimensional collective space. The last part of this lecture is devoted to new aspects encountered with radioactive beams specific properties of very extended neutron rich system, influence of pygmy or soft dipole resonances and charge exchange far from stability are discussed. (author)

Computational design and experimental validation of new thermal barrier systems

Energy Technology Data Exchange (ETDEWEB)

Guo, Shengmin [Louisiana State Univ., Baton Rouge, LA (United States)

2015-03-31

The focus of this project is on the development of a reliable and efficient ab initio based computational high temperature material design method which can be used to assist the Thermal Barrier Coating (TBC) bond-coat and top-coat design. Experimental evaluations on the new TBCs are conducted to confirm the new TBCs’ properties. Southern University is the subcontractor on this project with a focus on the computational simulation method development. We have performed ab initio density functional theory (DFT) method and molecular dynamics simulation on screening the top coats and bond coats for gas turbine thermal barrier coating design and validation applications. For experimental validations, our focus is on the hot corrosion performance of different TBC systems. For example, for one of the top coatings studied, we examined the thermal stability of TaZr_2.75O₈ and confirmed it’s hot corrosion performance.

Durability and CMAS Resistance of Advanced Environmental Barrier Coatings Systems for SiC/SiC Ceramic Matrix Composites

Science.gov (United States)

Zhu, Dongming

2015-01-01

Environmental barrier coatings (EBCs) and SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures with improved efficiency, reduce engine weight and cooling requirements. This paper will emphasize advanced environmental barrier coating developments for SiCSiC turbine airfoil components, by using advanced coating compositions and processing, in conjunction with mechanical and environment testing and durability validations. The coating-CMC degradations and durability in the laboratory simulated engine fatigue-creep and complex operating environments are being addressed. The effects of Calcium-Magnesium-Alumino-Silicate (CMAS) from road sand or volcano-ash deposits on the degradation mechanisms of the environmental barrier coating systems will be discussed. The results help understand the advanced EBC-CMC system performance, aiming at the durability improvements of more robust, prime-reliant environmental barrier coatings for successful applications of the component technologies and lifing methodologies.

Self-assembled pentablock copolymers for selective and sustained gene delivery

Energy Technology Data Exchange (ETDEWEB)

Zhang, Bingqi [Iowa State Univ., Ames, IA (United States)

2011-05-15

The poly(diethylaminoethyl methacrylate) (PDEAEM) - Pluronic F127 - PDEAEM pentablock copolymer (PB) gene delivery vector system has been found to possess an inherent selectivity in transfecting cancer cells over non-cancer cells in vitro, without attaching any targeting ligands. In order to understand the mechanism of this selective transfection, three possible intracellular barriers to transfection were investigated in both cancer and non-cancer cells. We concluded that escape from the endocytic pathway served as the primary intracellular barrier for PB-mediated transfection. Most likely, PB vectors were entrapped and rendered non-functional in acidic lysosomes of non-cancer cells, but survived in less acidic lysosomes of cancer cells. The work highlights the importance of identifying intracellular barriers for different gene delivery systems and provides a new paradigm for designing targeting vectors based on intracellular differences between cell types, rather than through the use of targeting ligands. The PB vector was further developed to simultaneously deliver anticancer drugs and genes, which showed a synergistic effect demonstrated by significantly enhanced gene expression in vitro. Due to the thermosensitive gelation behavior, the PB vector packaging both drug and gene was also investigated for its in vitro sustained release properties by using polyethylene glycol diacrylate as a barrier gel to mimic the tumor matrix in vivo. Overall, this work resulted in the development of a gene delivery vector for sustained and selective gene delivery to tumor cells for cancer therapy.

Selecting practice management information systems.

Science.gov (United States)

Worley, R; Ciotti, V

1997-01-01

Despite enormous advances in information systems, the process by which most medical practices select them has remained virtually unchanged for decades: the request for proposal (RFP). Unfortunately, vendors have learned ways to minimize the value of RFP checklists to where purchasers now learn little about the system functionality. The authors describe a selection methodology that replaces the RFP with scored demos, reviews of vendor user manuals and mathematically structured reference checking. In a recent selection process at a major medical center, these techniques yielded greater user buy-in and favorable contract terms as well.

Electro-Catalysis System for Biodiesel Synthesis from Palm Oil over Dielectric-Barrier Discharge Plasma Reactor

Directory of Open Access Journals (Sweden)

Istadi Istadi

2014-07-01

Full Text Available Biodiesel synthesis reaction routes from palm oil using plasma electro-catalysis process over Dielectric-Barrier Discharge (DBD plasma reactor were studied. The study was focused on finding possible reaction mechanism route during plasma electro-catalysis process. The prediction was performed based on the changes of Gas Chromatography Mass Spectrometer (GC-MS and Fourier Transform Infra Red (FT-IR analyses to the biodiesel products with respect to time length of plasma treatment. It was found that main reaction mechanism occurred in the plasma electro-catalysis system was non-thermal pyrolysis rather than transesterification. The main reactions within the plasma treatment were due to collision between high energetic electrons (supplied from high voltage power supply through high voltage electrode and the reaction mixtures. The high energetic electrons affected the electrons pair of covalent bonding to be excited or dissociated even ionized at higher energy. Therefore, this plasma electro-catalysis system was promising for biodiesel synthesis from vegetable oils due to only very short time reaction was needed, even no need a catalyst, no soap formation, and no glycerol by-product. This system could produce fatty acid methyl ester yield of 75.65% at 120 seconds and other possible chemicals, such as alkynes, alkanes, esters, carboxylic acid, and aldehydes. However, during the plasma process, the reaction mechanisms were still difficult to be controlled due the action of available high energetic electrons. The advanced studies on how to control the reaction mechanism selectively in the plasma electro-catalysis will be published elsewhere. © 2014 BCREC UNDIP. All rights reservedReceived: 23rd January 2014; Revised: 20th March 2014; Accepted: 23rd March 2014[How to Cite: Istadi, I., Yudhistira, A.D., Anggoro, D.D., Buchori, L. (2014. Electro-Catalysis System for Biodiesel Synthesis from Palm Oil over Dielectric-Barrier Discharge Plasma Reactor

Understanding the barriers to physician error reporting and disclosure: a systemic approach to a systemic problem.

Science.gov (United States)

Perez, Bianca; Knych, Stephen A; Weaver, Sallie J; Liberman, Aaron; Abel, Eileen M; Oetjen, Dawn; Wan, Thomas T H

2014-03-01

The issues of medical errors and medical malpractice have stimulated significant interest in establishing transparency in health care, in other words, ensuring that medical professionals formally report medical errors and disclose related outcomes to patients and families. However, research has amply shown that transparency is not a universal practice among physicians. A review of the literature was carried out using the search terms "transparency," "patient safety," "disclosure," "medical error," "error reporting," "medical malpractice," "doctor-patient relationship," and "physician" to find articles describing physician barriers to transparency. The current literature underscores that a complex Web of factors influence physician reluctance to engage in transparency. Specifically, 4 domains of barriers emerged from this analysis: intrapersonal, interpersonal, institutional, and societal. Transparency initiatives will require vigorous, interdisciplinary efforts to address the systemic and pervasive nature of the problem. Several ethical and social-psychological barriers suggest that medical schools and hospitals should collaborate to establish continuity in education and ensure that knowledge acquired in early education is transferred into long-term learning. At the institutional level, practical and cultural barriers suggest the creation of supportive learning environments and private discussion forums where physicians can seek moral support in the aftermath of an error. To overcome resistance to culture transformation, incremental change should be considered, for example, replacing arcane transparency policies and complex reporting mechanisms with clear, user-friendly guidelines.

Comparative Analysis of AHP-TOPSIS and Fuzzy AHP Models in Selecting Appropriate Nanocomposites for Environmental Noise Barrier Applications

Science.gov (United States)

Naderzadeh, Mahdiyeh; Arabalibeik, Hossein; Monazzam, Mohammad Reza; Ghasemi, Ismaeil

Choosing the right material in the design of environmental noise barriers has always been a challenging issue in acoustics. In less-developed countries, the material selection is affected by many factors from various aspects, which makes the decision-making very complicated. This study attempts to compare and assign weights to the most important indices affecting the choice of appropriate noise barrier material. These criteria include absorption coefficient, transparency, tensile modulus, strength at yield, elongation at break, impact strength, flexural modulus, hardness, and cost. For this purpose, experts' opinions was gathered through a total of 13 questionnaires and used for assigning weights by Analytic Hierarchy Process (AHP) and Fuzzy Analytic Hierarchy process (FAHP) techniques. According to the AHP results, impact strength, with only a minor difference of 0.093 compared to the AHP, was recognized as the most important criterion. Finally, the optimal composite material was selected using two different methods; first by Technique for Order-Preference by Similarity to Ideal Solution (TOPSIS) based on the weights obtained from AHP, and next by directly applying the obtained weights from FAHP to the true measured values of parameters. As the results show, in both abovementioned methods, Polycarbonate-SiO2 0.3% with roughened surface (PCSI3-R) received the highest score and was selected as the preferred composite material. Given the close similarity of the results, to determine the superiority of one method over the other, some noise was added to the original data set from the mechanical and acoustic tests and then the variance of the changes in the final orders of preferences was calculated. This indicates the robustness of the method against the measurement errors and noise. The results shows that under the same circumstances, the overall order shift variance in the classic TOPSIS is six times higher than that of the fuzzy AHP method.

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. ...

The Hybridization Barrier between Herbaceous Medicago sativa and Woody M. arborea Is Weakened by Selection of Seed Parents

Directory of Open Access Journals (Sweden)

Edwin Bingham

2013-05-01

Full Text Available Medicago sativa, alfalfa or lucerne, and M. arborea were considered reproductively isolated until recently. Then, in 2003, an alfalfa genotype was identified that produced a few seeds and progeny with hybrid traits after a large number of pollinations by M. arborea. A derivative of this alfalfa genotype also produced a low frequency of progeny with hybrid traits. Thus, the hybridization barrier was weakened by selection of seed parents. Hybrids from both events expressed traits from M. arborea and M. arborea-specific DNA bands, although more of the M. sativa genome was retained, based on the DNA results. Thus, there was chromatin elimination during embryogenesis, resulting in partial hybrids (hereafter hybrids. However, more than 30 hybrids with an array of M. arborea traits have been obtained thus far, and research continues on the nature of the hybrids. Traits have been genetically transmitted in crosses, and selected traits are in use for alfalfa breeding. This paper reviews the first hybrids and then focuses on further weakening of the hybridization barrier with the discovery of a more efficient hybridizer derived from crossing Medicago sativa subspecies, sativa, coerulea and falcata. This genotype was found to have reproductive abnormalities associated with its complex subspecies origin that are best described as hybrid breakdown. In effect, this subspecies derivative is a bridge-cross parent that consistently produces hybrids. Reproductive abnormalities in the bridge-cross parent are reported and discussed.

The Hybridization Barrier between Herbaceous Medicago sativa and Woody M. arborea Is Weakened by Selection of Seed Parents

Science.gov (United States)

Bingham, Edwin; Armour, David; Irwin, John

2013-01-01

Medicago sativa, alfalfa or lucerne, and M. arborea were considered reproductively isolated until recently. Then, in 2003, an alfalfa genotype was identified that produced a few seeds and progeny with hybrid traits after a large number of pollinations by M. arborea. A derivative of this alfalfa genotype also produced a low frequency of progeny with hybrid traits. Thus, the hybridization barrier was weakened by selection of seed parents. Hybrids from both events expressed traits from M. arborea and M. arborea-specific DNA bands, although more of the M. sativa genome was retained, based on the DNA results. Thus, there was chromatin elimination during embryogenesis, resulting in partial hybrids (hereafter hybrids). However, more than 30 hybrids with an array of M. arborea traits have been obtained thus far, and research continues on the nature of the hybrids. Traits have been genetically transmitted in crosses, and selected traits are in use for alfalfa breeding. This paper reviews the first hybrids and then focuses on further weakening of the hybridization barrier with the discovery of a more efficient hybridizer derived from crossing Medicago sativa subspecies, sativa, coerulea and falcata. This genotype was found to have reproductive abnormalities associated with its complex subspecies origin that are best described as hybrid breakdown. In effect, this subspecies derivative is a bridge-cross parent that consistently produces hybrids. Reproductive abnormalities in the bridge-cross parent are reported and discussed. PMID:27137379

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...

Socio-cultural barriers to the development of a sustainable energy system - the case of hydrogen

DEFF Research Database (Denmark)

Petersen, Lars Kjerulf; Andersen, Anne Holst

Any transition to a more sustainable energy system, radically reducing greenhouse gas emissions, is bound to run in to a host of different barriers - technological and economic, but also socio-cultural. This will also be the case for any large-scale application of hydrogen as energy carrier......, especially if the system is going to be based on renewable energy sources. The aim of these research notes is to review and discuss major socio-cultural barriers to new forms of energy supply in general and to hydrogen specifically. Reaching sufficient reductions in greenhouse gas emissions may require more...

Application of CFRP with High Hydrogen Gas Barrier Characteristics to Fuel Tanks of Space Transportation System

Science.gov (United States)

Yonemoto, Koichi; Yamamoto, Yuta; Okuyama, Keiichi; Ebina, Takeo

In the future, carbon fiber reinforced plastics (CFRPs) with high hydrogen gas barrier performance will find wide applications in all industrial hydrogen tanks that aim at weight reduction; the use of such materials will be preferred to the use of conventional metallic materials such as stainless steel or aluminum. The hydrogen gas barrier performance of CFRP will become an important issue with the introduction of hydrogen-fuel aircraft. It will also play an important role in realizing fully reusable space transportation system that will have high specific tensile CFRP structures. Such materials are also required for the manufacture of high-pressure hydrogen gas vessels for use in the fuel cell systems of automobiles. This paper introduces a new composite concept that can be used to realize CFRPs with high hydrogen gas barrier performance for applications in the cryogenic tanks of fully reusable space transportation system by the incorporation of a nonmetallic crystal layer, which is actually a dense and highly oriented clay crystal laminate. The preliminary test results show that the hydrogen gas barrier characteristics of this material after cryogenic heat shocks and cyclic loads are still better than those of other polymer materials by approximately two orders of magnitude.

Barriers to Implementing a Reporting and Learning Patient Safety System: Pediatric Chiropractic Perspective.

Science.gov (United States)

Pohlman, Katherine A; Carroll, Linda; Hartling, Lisa; Tsuyuki, Ross T; Vohra, Sunita

2016-04-01

A reporting and learning system is a method of monitoring the occurrence of incidents that affect patient safety. This cross-sectional survey asked pediatric chiropractors about factors that may limit their participation in such a system. The list of potential barriers for participation was developed using a systematic approach. All members of the 2 pediatric councils associated with US national chiropractic organizations were invited to complete the survey (N = 400). The cross-sectional survey was created using an online survey tool (REDCap) and sent directly to member emails addressed by the respective executive committees. Of the 400 potential respondents, 81 responded (20.3%). The most common limitations to participating were identified as time pressure (96%) and patient concerns (81%). Reporting and learning systems have been utilized to increase safety awareness in many high-risk industries. To be successful, future patient safety studies with pediatric chiropractors need to ensure these barriers are understood and addressed. © The Author(s) 2015.

Strategies to overcome barriers for cleaner generation technologies in small developing power systems: Sri Lanka case study

International Nuclear Information System (INIS)

Wijayatunga, Priyantha D.C.; Siriwardena, Kanchana; Fernando, W.J.L.S.; Shrestha, Ram M.; Attalage, Rahula A.

2006-01-01

The penetration of cleaner and energy efficient technologies in small power systems such as the one in Sri Lanka has encountered many problems. This has caused major concerns among the policy makers, mainly in the context of the growing need to reduce harmful emissions in the electricity supply industry from the point of view of both local environmental pollution as well as the global warming concerns. This paper presents the outcome of a study involved in identifying and ranking the barriers to the promotion of cleaner and energy efficient technologies and strategies to overcome these barriers in Sri Lanka. Barriers for renewable energy based systems such as wind and wood fuel fired plants (dendro thermal power) and cleaner technologies such as liquefied natural gas (LNG) fired combined cycle and IGCC (coal) were identified based on a survey. A direct assessment multi-criteria decision making method called Analytic Hierarchy Process (AHP) was used to rank the barriers. The most effective strategies are proposed to address the three major barriers for each of these technologies based on extensive discussions with all the stakeholders in the electricity industry. It was found that lack of financing instruments, high initial cost and lack of assurance of resource supply or availability are the main barriers for renewable technologies. As for cleaner fuel and technology options associated with conventional generation systems, the lack of a clear government policy, uncertainty of fuel supplies and their prices and the reliability of the technologies themselves are the major barriers. Strategies are identified to overcome the above barriers. Establishment of a proper feed in tariff, geographical diversification of installations and capacity building in commercial banks are suggested for wind power. Investment incentives, streamlining of wood production and research on site identification are proposed for wood fuel fired plants. Also the study suggests delayed

Implementation of renewable energy technology - Opportunities and barriers. Summary of country studies

Energy Technology Data Exchange (ETDEWEB)

Painuly, J.P.; Fenhann, J.V.

2002-07-01

The project was launched to identify barriers to the implementation of renewable energy technologies (RETs) and explore measures to overcome the identified barriers. National institutions in Egypt, Ghana and Zimbabwe carried out the country studies based on the basic methodological framework provided by the UNEP Centre. The objectives of the project included strengthening institutional capacity for analysis and implementation of RET projects in the participating countries and bring out experiences on RETs barriers and removal measures for dissemination so that others can benefit from the knowledge so gained. An important highlight of the studies was involvement of stake holders in the process of identification of barriers and measures to remove them. A preliminary identification of relevant RETs for their countries was done by the country teams in the initial stage of the project. After that, national workshops involving various stake holders were held between July and September 1999 to discuss the RETs and barriers to their implementation. Based on the discussions, a few important RETs were identified for more detailed study. PV systems for rural electrification, solar water heating systems and large-scale biogas system were identified and analysed for barriers in the Egypt country study. Economic, information and policy barriers were identified as major barriers for these technologies. Solar water pumps, biogas and small hydro were the focus of study in Ghana. In this case also, economic, information and policy barriers were found to be the important barriers for the selected technologies. In the case of Zimbabwe, focus was on identification of primary and secondary barriers to RETs dissemination. The primary barriers included lack of capacity to develop proposals, lack of information for policy making and framework for information dissemination. The study concluded that the secondary barriers as seen and experienced by the stake holders are due to primary

The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities in Assessing the Degradation of Cementitious Barriers - 13487

Energy Technology Data Exchange (ETDEWEB)

Flach, G.P.; Burns, H.H.; Langton, C.; Smith, F.G. III [Savannah River National Laboratory, Savannah River Site, Aiken SC 29808 (United States); Brown, K.G.; Kosson, D.S.; Garrabrants, A.C.; Sarkar, S. [Vanderbilt University, Nashville, TN (United States); Van der Sloot, H. [Hans Van der Sloot Consultancy (Netherlands); Meeussen, J.C.L. [Nuclear Research and Consultancy Group, Petten (Netherlands); Samson, E. [SIMCO Technologies Inc., 1400, boul. du Parc-Technologique, Suite 203, Quebec (Canada); Mallick, P.; Suttora, L. [United States Department of Energy, 1000 Independence Ave. SW, Washington, DC (United States); Esh, D.W.; Fuhrmann, M.J.; Philip, J. [U.S. Nuclear Regulatory Commission, Washington, DC (United States)

2013-07-01

The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste and Nuclear Materials Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to 100 years and longer for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox has produced tangible benefits to the DOE Performance Assessment (PA) community. A review of prior DOE PAs has provided a list of potential opportunities for improving cementitious barrier performance predictions through the use of the CBP software tools. These opportunities include: 1) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, 2) prediction of changes in K{sub d}/mobility as a function of time that result from changing pH and redox conditions, 3) concrete degradation from rebar corrosion due to carbonation, 4) early age cracking from drying and/or thermal shrinkage and 5) degradation due to sulfate attack. The CBP has already had opportunity to provide near-term, tangible support to ongoing DOE-EM PAs such as the Savannah River Saltstone Disposal Facility (SDF) by providing a sulfate attack analysis that predicts the extent and damage that sulfate ingress will have on the concrete vaults over extended time (i.e., > 1000 years). This analysis is one of the many technical opportunities in cementitious barrier performance that can be addressed by the DOE-EM sponsored CBP

Professional perspectives on systemic barriers to admission avoidance: learning from a system dynamics study of older people's admission pathways.

Science.gov (United States)

Walsh, Bronagh; Lattimer, Valerie; Wintrup, Julie; Brailsford, Sally

2015-06-01

There is debate worldwide about the best way to manage increased healthcare demand within ageing populations, particularly rising rates of unplanned and avoidable hospital admissions. To understand health and social care professionals' perspectives on barriers to admission avoidance throughout the admissions journey, in particular: the causes of avoidable admissions in older people; drivers of admission and barriers to use of admission avoidance strategies; and improvements to reduce unnecessary admissions. A qualitative framework analysis of interview data from a System dynamics (SD) modelling study. Semi-structured interviews were conducted with twenty health and social care professionals with experience of older people's admissions. The interviews were used to build understanding of factors facilitating or hindering admission avoidance across the admissions system. Data were analysed using framework analysis. Three overarching themes emerged: understanding the needs of the patient group; understanding the whole system; and systemwide access to expertise in care of older people. There were diverse views on the underlying reasons for avoidable admissions and recognition of the need for whole-system approaches to service redesign. Participants recommended system redesign that recognises the specific needs of older people, but there was no consensus on underlying patient needs or specific service developments. Access to expertise in management of older and frailer patients was seen as a barrier to admission avoidance throughout the system. Providing access to expertise and leadership in care of frail older people across the admissions system presents a challenge for service managers and nurse educators but is seen as a prerequisite for effective admission avoidance. System redesign to meet the needs of frail older people requires agreement on causes of avoidable admission and underlying patient needs. © 2014 John Wiley & Sons Ltd.

Investigation of endothelial growth using a sensors-integrated microfluidic system to simulate physiological barriers

Directory of Open Access Journals (Sweden)

Rajabi Taleieh

2015-09-01

Full Text Available In this paper we present a microfluidic system based on transparent biocompatible polymers with a porous membrane as substrate for various cell types which allows the simulation of various physiological barriers under continuous laminar flow conditions at distinct tunable shear rates. Besides live cell and fluorescence microscopy, integrated electrodes enable the investigation of the permeability and barrier function of the cell layer as well as their interaction with external manipulations using the Electric Cell-substrate Impedance Sensing (ECIS method.

Development and Property Evaluation of Selected HfO2-Silicon and Rare Earth-Silicon Based Bond Coats and Environmental Barrier Coating Systems for SiC/SiC Ceramic Matrix Composites

Science.gov (United States)

Zhu, Dongming

2016-01-01

Ceramic environmental barrier coatings (EBC) and SiC/SiC ceramic matrix composites (CMCs) will play a crucial role in future aircraft propulsion systems because of their ability to significantly increase engine operating temperatures, improve component durability, reduce engine weight and cooling requirements. Advanced EBC systems for SiC/SiC CMC turbine and combustor hot section components are currently being developed to meet future turbine engine emission and performance goals. One of the significant material development challenges for the high temperature CMC components is to develop prime-reliant, high strength and high temperature capable environmental barrier coating bond coat systems, since the current silicon bond coat cannot meet the advanced EBC-CMC temperature and stability requirements. In this paper, advanced NASA HfO2-Si and rare earth Si based EBC bond coat EBC systems for SiC/SiC CMC combustor and turbine airfoil applications are investigated. High temperature properties of the advanced EBC systems, including the strength, fracture toughness, creep and oxidation resistance have been studied and summarized. The advanced NASA EBC systems showed some promise to achieve 1500C temperature capability, helping enable next generation turbine engines with significantly improved engine component temperature capability and durability.

Engineered Barrier System performance requirements systems study report. Revision 02

International Nuclear Information System (INIS)

Balady, M.A.

1997-01-01

This study evaluates the current design concept for the Engineered Barrier System (EBS), in concert with the current understanding of the geologic setting to assess whether enhancements to the required performance of the EBS are necessary. The performance assessment calculations are performed by coupling the EBS with the geologic setting based on the models (some of which were updated for this study) and assumptions used for the 1995 Total System Performance Assessment (TSPA). The need for enhancements is determined by comparing the performance assessment results against the EBS related performance requirements. Subsystem quantitative performance requirements related to the EBS include the requirement to allow no more than 1% of the waste packages (WPs) to fail before 1,000 years after permanent closure of the repository, as well as a requirement to control the release rate of radionuclides from the EBS. The EBS performance enhancements considered included additional engineered components as well as evaluating additional performance available from existing design features but for which no performance credit is currently being taken

Engineered Barrier System performance requirements systems study report. Revision 02

Energy Technology Data Exchange (ETDEWEB)

Balady, M.A.

1997-01-14

This study evaluates the current design concept for the Engineered Barrier System (EBS), in concert with the current understanding of the geologic setting to assess whether enhancements to the required performance of the EBS are necessary. The performance assessment calculations are performed by coupling the EBS with the geologic setting based on the models (some of which were updated for this study) and assumptions used for the 1995 Total System Performance Assessment (TSPA). The need for enhancements is determined by comparing the performance assessment results against the EBS related performance requirements. Subsystem quantitative performance requirements related to the EBS include the requirement to allow no more than 1% of the waste packages (WPs) to fail before 1,000 years after permanent closure of the repository, as well as a requirement to control the release rate of radionuclides from the EBS. The EBS performance enhancements considered included additional engineered components as well as evaluating additional performance available from existing design features but for which no performance credit is currently being taken.

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.

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.

Measurements of barrier distributions for the system {sup 8}Li+{sup 120}Sn

Energy Technology Data Exchange (ETDEWEB)

Rossi Junior, E.S. [Centro Universitario FIEO (UNIFIEO), Osasco, SP (Brazil); Guimaraes, V.; Barioni, A.; Morais, M.C.; Faria, P.N. de; Lepine-Szily, A.; Lichtenthaeler Filho, R.; Crema, E.; Cardona, J.C.A. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Monteiro, D.S. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Fisica; Huiza, J.F.P. [Universidade Estadual do Sudoeste da Bahia (UESB), Jequie, BA (Brazil); Shorto, J.M.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

Full text: The investigation of exotic nuclei, where the appearance of various effects and phenomena such as halo effect, skin of nucleons, new forms of decay, different spacing between the levels and new magic numbers in the shell model, has attracted a great motivation to investigate and study these nuclei in detail. Thus, important effects such as competition and interference between the reaction mechanisms, coupling between channels, can be investigated and analyzed in detail. The results of precise measurements of quasi-elastic barrier distributions can be used to develop and verify the validity of new models of reactions and new analytical techniques, making use of polarization potentials and calculations of CDCC (Continuum Discretized Coupled Channels). These measurements at energies near the Coulomb barrier can provide also information about the nuclear structure and reaction mechanisms. Recently, measurements of quasi-elastic barrier distributions for the system {sup 8}Li + {sup 120}Sn were carried out at energies around the Coulomb barrier (19.0, 20.4, 21.4 and 23.5 MeV) at the Pelletron laboratory. In this work, we will present the preliminary results of those measurements. (author)

Combined Thermomechanical and Environmental Durability of Environmental Barrier Coating Systems on SiC/SiC Ceramic Matrix Composites

Science.gov (United States)

Zhu, Dongming; Harder, Bryan; Bhatt, Ramakrishna

2016-01-01

Environmental barrier coatings (EBCs) and SiC/SiC ceramic matrix composites (CMCs) will play a crucial role in next generation turbine engines for hot-section component applications. The development of prime-reliant environmental barrier coatings is essential to the EBC-CMC system durability, ensuring the successful implementations of the high temperature and lightweight engine component technologies for engine applications.This paper will emphasize recent NASA environmental barrier coating and CMC developments for SiC/SiC turbine airfoil components, utilizing advanced coating compositions and processing methods. The emphasis has been particularly placed on thermomechanical and environment durability evaluations of EBC-CMC systems. We have also addressed the integration of the EBCs with advanced SiC/SiC CMCs, and studied the effects of combustion environments and Calcium-Magnesium-Alumino-Silicate (CMAS) deposits on the durability of the EBC-CMC systems under thermal gradient and mechanical loading conditions. Advanced environmental barrier coating systems, including multicomponent rare earth silicate EBCs and HfO2-Si based bond coats, will be discussed for the performance improvements to achieve better temperature capability and CMAS resistance for future engine operating conditions.

Optimization of the Ultrasound-Induced Blood-Brain Barrier Opening

OpenAIRE

Konofagou, Elisa E.

2012-01-01

Current treatments of neurological and neurodegenerative diseases are limited due to the lack of a truly non-invasive, transient, and regionally selective brain drug delivery method. The brain is particularly difficult to deliver drugs to because of the blood-brain barrier (BBB). The impermeability of the BBB is due to the tight junctions connecting adjacent endothelial cells and highly regulatory transport systems of the endothelial cell membranes. The main function of the BBB is ion and vol...

Barriers And Motivators for Smoking Cessation in Patients With Systemic Lupus Erythematosus (SLE).

Science.gov (United States)

Terrell, Deirdra R; Stewart, Lauren M; Tolma, Eleni L; McClain, Rebekah; Vesely, Sara K; James, Judith A

2015-11-01

Although studies have shown that smoking is detrimental to the health of patients with systemic lupus erythematosus (SLE), studies regarding barriers and motivators for smoking cessation are lacking. The purpose of this study was to generate hypotheses regarding the barriers and motivators for smoking cessation in SLE patients. This study was based on the theoretical framework of the stages of change model. All participants met SLE classification criteria. Interviews were conducted with 16 current and 10 former smokers. Motivators included: medical reasons, readiness, and concern for others. Barriers included: enjoyment, coping mechanism, and an emotional connection. Participants were unsure of the impact of smoking on their medication and disease, and had mixed feelings regarding the impact on pain. The main motivator for cessation in this population was concern for one's health. Rheumatologists need to include disease specific harms and assess pain management strategies as part of cessation counseling.

Decision support system to select cover systems

International Nuclear Information System (INIS)

Bostick, K.V.

1995-01-01

The objective of this technology is to provide risk managers with a defensible, objective way to select capping alternatives for remediating radioactive and mixed waste landfills. The process of selecting containment cover technologies for mixed waste landfills requires consideration of many complex and interrelated technical, regulatory, and economic issues. A Decision Support System (DSS) is needed to integrate the knowledge of experts from scientific, engineering, and management disciplines to help in selecting the best capping practice for the site

Studies on an advanced repository system with enhanced engineered barriers (a framework)

International Nuclear Information System (INIS)

Fujiwara, A.; Tashiro, S.; Ikari, S.; Suzuki, A.

1993-01-01

In order to propose advanced designs of repositories with enhanced engineered barriers of relatively high radioactive wastes such as burnable poisons, channel boxes, control rods and highly irradiated metals, studies started in 1987 and completed the first phase in 1992. This paper presents the framework and brief results of the first phase. The studies set preliminary design concepts of the repositories with various combinations with engineered barriers and natural barriers for different models and locations such as a silo type in shallow land or a tunnel type in intermediate depth. Through the designs, four component technics were picked up and studied for (1) construction of the components in repository; (2) performance evaluation to realize repository design; (3) improvement of circumstances inside or around repository; and (4) surveillance of repository performance to realize the repository designs. Finally, some repository systems were provided using obtained results, and then the applicability and the economy were evaluated. The studies will continue to the second phase focusing on the long-term performance of the repositories

Monitoring long-term evolution of engineered barrier systems using magnets: Magnetic response.

Science.gov (United States)

Rigonat, N; Isnard, O; Harley, S L; Butler, I B

2018-01-05

Remote and non-destructive monitoring of the stability and performance of Engineered Barrier Systems for Geological Disposal Facility of is gaining considerable importance in establishing the safety cases for Higher Activity Wastes disposal. This study offers an innovative use of mineral magnetism for monitoring groundwater saturation of the barrier. Four mixtures of permanent magnets (Nd-Fe-B, coated and uncoated; SmCo and AlNiCo) and bentonite were reacted for 4, 8 and 12 months with mildly-saline, high-pH leachates, representing the fluids saturating a time-evolved engineered barrier. Coupled hysteresis and thermomagnetic analyses demonstrate how Nd-Fe-B feature a time-dependent transition from square-like ferromagnetic to superparamagnetic loop via pot-bellied and wasp-waist loops, whereas SmCo and AlNiCo do not show so extensive corrosion-related variations of the intrinsic and extrinsic magnetic properties. This study allowed to identify magnetic materials suitable for shorter- (Nd-Fe-B) and longer-term (SmCo and AlNiCo) monitoring purposes. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

The Blood-Brain Barrier: An Engineering Perspective

Directory of Open Access Journals (Sweden)

Andrew eWong

2013-08-01

Full Text Available It has been more than 100 years since Paul Ehrlich reported that various water-soluble dyes injected into the circulation did not enter the brain. Since Ehrlich’s first experiments, only a small number of molecules, such as alcohol and caffeine have been found to cross the blood-brain barrier, and it remains the major roadblock to treatment of many central nervous system diseases. At the same time, many central nervous system diseases are associated with disruption of the blood-brain barrier that can lead to changes in permeability, modulation of immune cell transport, and trafficking of pathogens into the brain. Therefore advances in our understanding of the structure and function of the blood-brain barrier are key to advances in treatment of a wide range of central nervous system diseases. Over the past 10 years it has become recognized that the blood-brain barrier is a complex dynamic system that involves biomechanical and biochemical signaling between the vascular system and the brain. Here we reconstruct the structure, function, and transport properties of the blood-brain barrier from an engineering perspective. New insight into the physics of the blood-brain barrier could ultimately lead to clinical advances in the treatment of central nervous system diseases.

Waste package/engineered barrier system design concepts for the direct disposal of spent fuel in the potential United States' repository at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Stahl, D.; Harrison, D.J.

1993-01-01

The goal of the US Department of Energy's (DOE) Yucca Mountain Site Characterization Project (YMP) waste package development program is to design a waste package and associated engineered barrier system (EBS) that meets the applicable regulatory requirements for safe disposal of spent nuclear fuel and solidified high-level waste (HLW) in a geologic repository. Attainment of this goal relies on a multi-barrier approach, the unsaturated nature of the Yucca Mountain site, consideration of technical alternatives, and sufficient resolution of technical and regulatory uncertainties. To accomplish this, an iterative system engineering approach will be used. The NWPA of 1982 limits the content of the first US repository to 70,000 metric tons of heavy metal (MTHM). The DOE Mission Plan describes the implementation of the provisions of the NWPA for the waste management system. The Draft 1988 approach will involve selecting candidate designs, evaluating them against performance requirements, and then selecting one or two preferred designs for further detailed evaluation and final design. The reference design of the waste package described in the YMP Site Characterization Plan is a thin-walled, vertical borehole-emplaced waste package with an air gap between the package and the rock wall. The reference design appeared to meet the design requirement. However, the degree of uncertainty was large. This uncertainty led to considering several more-robust design concepts during the Advanced Conceptual Design phase of the program that include small, drift-emplaced packages and higher capacity, drift-emplaced packages, both partially and totally self-shielded. Metallic as well as ceramic materials are being considered

Pathways for Small Molecule Delivery to the Central Nervous System Across the Blood-Brain Barrier

OpenAIRE

Mikitsh, John L; Chacko, Ann-Marie

2014-01-01

The treatment of central nervous system (CNS) disease has long been difficult due to the ineffectiveness of drug delivery across the blood-brain barrier (BBB). This review summarizes important concepts of the BBB in normal versus pathophysiology and how this physical, enzymatic, and efflux barrier provides necessary protection to the CNS during drug delivery, and consequently treatment challenging. Small molecules account for the vast majority of available CNS drugs primarily due to their abi...

A chromia forming thermal barrier coating system

Energy Technology Data Exchange (ETDEWEB)

Taylor, M.P.; Evans, H.E. [Metallurgy and Materials, The University of Birmingham, Birmingham, B15 2TT (United Kingdom); Gray, S.; Nicholls, J.R. [Surface Science and Engineering Centre, Cranfield University, Cranfield, MK43 0AL (United Kingdom)

2011-07-15

Conventional thermal barrier coating (TBC) systems consist of an insulating ceramic topcoat, a bond coat for oxidation protection and the underlying superalloy designed to combat the oxidising conditions in aero- and land-based gas turbines. Under high-temperature oxidation, the use of an alumina forming bond coat is warranted, thus all current TBC systems are optimised for the early formation of a dense, protective thermally grown oxide (TGO) of alumina. This also offers protection against Type I hot corrosion but a chromia layer gives better protection against Type II corrosion and intermediate temperatures, the conditions found in land-based gas turbines. In this paper the authors present the first known results for a chromia forming TBC system. Tests have been performed under oxidising conditions, up to 1000 h, at temperatures between 750 C and 900 C, and under Type I (900 C) and Type II (700 C) hot corrosion conditions up to 500 h. Under all these conditions no cracking, spallation or degradation was observed. Examination showed the formation of an adherent, dense chromia TGO at the bond coat / topcoat interface. These initial results are very encouraging and the TGO thicknesses agree well with comparable results reported in the literature. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Development of Advanced Environmental Barrier Coatings for SiC/SiC Ceramic Matrix Composites: Path Toward 2700 F Temperature Capability and Beyond

Science.gov (United States)

Zhu, Dongming; Harder, Bryan; Hurst, Janet B.; Good, Brian; Costa, Gustavo; Bhatt, Ramakrishna T.; Fox, Dennis S.

2017-01-01

Advanced environmental barrier coating systems for SiC-SiC Ceramic Matrix Composite (CMC) turbine and combustor hot section components are currently being developed to meet future turbine engine emission and performance goals. One of the significant coating development challenges is to achieve prime-reliant environmental barrier coating systems to meet the future 2700F EBC-CMC temperature stability and environmental durability requirements. This presentation will emphasize recent NASA environmental barrier coating system testing and down-selects, particularly the development path and properties towards 2700-3000F durability goals by using NASA hafnium-hafnia-rare earth-silicon-silicate composition EBC systems for the SiC-SiC CMC turbine component applications. Advanced hafnium-based compositions for enabling next generation EBC and CMCs capabilities towards ultra-high temperature ceramic coating systems will also be briefly mentioned.

Selective ablation of the androgen receptor in mouse sertoli cells affects sertoli cell maturation, barrier formation and cytoskeletal development.

Directory of Open Access Journals (Sweden)

Ariane Willems

2010-11-01

Full Text Available The observation that mice with a selective ablation of the androgen receptor (AR in Sertoli cells (SC (SCARKO mice display a complete block in meiosis supports the contention that SC play a pivotal role in the control of germ cell development by androgens. To delineate the physiological and molecular mechanism responsible for this control, we compared tubular development in pubertal SCARKO mice and littermate controls. Particular attention was paid to differences in SC maturation, SC barrier formation and cytoskeletal organization and to the molecular mediators potentially involved. Functional analysis of SC barrier development by hypertonic perfusion and lanthanum permeation techniques and immunohistochemical analysis of junction formation showed that SCARKO mice still attempt to produce a barrier separating basal and adluminal compartment but that barrier formation is delayed and defective. Defective barrier formation was accompanied by disturbances in SC nuclear maturation (immature shape, absence of prominent, tripartite nucleoli and SC polarization (aberrant positioning of SC nuclei and cytoskeletal elements such as vimentin. Quantitative RT-PCR was used to study the transcript levels of genes potentially related to the described phenomena between day 8 and 35. Differences in the expression of SC genes known to play a role in junction formation could be shown from day 8 for Cldn11, from day 15 for Cldn3 and Espn, from day 20 for Cdh2 and Jam3 and from day 35 for ZO-1. Marked differences were also noted in the transcript levels of several genes that are also related to cell adhesion and cytoskeletal dynamics but that have not yet been studied in SC (Actn3, Ank3, Anxa9, Scin, Emb, Mpzl2. It is concluded that absence of a functional AR in SC impedes the remodeling of testicular tubules expected at the onset of spermatogenesis and interferes with the creation of the specific environment needed for germ cell development.

Noble magnetic barriers in the ASDEX UG tokamak

Science.gov (United States)

Ali, Halima; Punjabi, Alkesh; Vazquez, Justin

2010-02-01

The second-order perturbation method of creating invariant tori inside chaos in Hamiltonian systems (Ali, H.; Punjabi, A. Plasma Phys. Contr. F. 2007, 49, 1565-1582) is applied to the axially symmetric divertor experiment upgrade (ASDEX UG) tokamak to build noble irrational magnetic barriers inside chaos created by resonant magnetic perturbations (m, n)=(3, 2)+(4, 3), with m and n the poloidal and toroidal mode numbers of the Fourier expansion of the magnetic perturbation. The radial dependence of the Fourier modes is ignored. The modes are considered to be locked and have the same amplitude δ. A symplectic mathematical mapping in magnetic coordinates is used to integrate magnetic field line trajectories in the ASDEX UG. Tori with noble irrational rotational transform are the last ones to be destroyed by perturbation in Hamiltonian systems. For this reason, noble irrational magnetic barriers are built inside chaos, and the strongest noble irrational barrier is identified. Three candidate locations for the strongest noble barrier in ASDEX UG are selected. All three candidate locations are chosen to be roughly midway between the resonant rational surfaces ψ32 and ψ43. ψ is the magnetic coordinate of the flux surface. The three candidate surfaces are the noble irrational surfaces close to the surface with q value that is a mediant of q=3/2 and 4/3, q value of the physical midpoint of the two resonant surfaces, and the q value of the surface where the islands of the two perturbing modes just overlap. These q values of the candidate surfaces are denoted by q MED, q MID, and q OVERLAP. The strongest noble barrier close to q MED has the continued fraction representation (CFR) [1;2,2,1∞] and exists for δ≤2.6599×10-4; the strongest noble barrier close to q MID has CFR [1;2,2,2,1∞] and exists for δ≤4.6311×10-4; and the strongest noble barrier close to q OVERLAP has CFR [1;2,2,6,2,1∞] and exists for δ≤1.367770×10-4. From these results, the strongest

The patient work system: an analysis of self-care performance barriers among elderly heart failure patients and their informal caregivers.

Science.gov (United States)

Holden, Richard J; Schubert, Christiane C; Mickelson, Robin S

2015-03-01

Human factors and ergonomics approaches have been successfully applied to study and improve the work performance of healthcare professionals. However, there has been relatively little work in "patient-engaged human factors," or the application of human factors to the health-related work of patients and other nonprofessionals. This study applied a foundational human factors tool, the systems model, to investigate the barriers to self-care performance among chronically ill elderly patients and their informal (family) caregivers. A Patient Work System model was developed to guide the collection and analysis of interviews, surveys, and observations of patients with heart failure (n = 30) and their informal caregivers (n = 14). Iterative analyses revealed the nature and prevalence of self-care barriers across components of the Patient Work System. Person-related barriers were common and stemmed from patients' biomedical conditions, limitations, knowledge deficits, preferences, and perceptions as well as the characteristics of informal caregivers and healthcare professionals. Task barriers were also highly prevalent and included task difficulty, timing, complexity, ambiguity, conflict, and undesirable consequences. Tool barriers were related to both availability and access of tools and technologies and their design, usability, and impact. Context barriers were found across three domains-physical-spatial, social-cultural, and organizational-and multiple "spaces" such as "at home," "on the go," and "in the community." Barriers often stemmed not from single factors but from the interaction of several work system components. Study findings suggest the need to further explore multiple actors, contexts, and interactions in the patient work system during research and intervention design, as well as the need to develop new models and measures for studying patient and family work. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Investigation on the Interface Characteristics of the Thermal Barrier Coating System through Flat Cylindrical Indenters

Directory of Open Access Journals (Sweden)

Shifeng Wen

2014-01-01

Full Text Available Thermal barrier coating (TBC systems are highly advanced material systems and usually applied to insulate components from large and prolonged heat loads by utilizing thermally insulating materials. In this study, the characteristics of the interface of thermal barrier coating systems have been simulated by the finite-element method (FEM. The emphasis was put on the stress distribution at the interface which is beneath the indenter. The effect of the interface roughness, the thermally grown oxide (TGO layer's thickness, and the modulus ratio (η of the thin film with the substrate has been considered. Finite-element results showed that the influences of the interface roughness and the TGO layer's thickness on stress distribution were important. At the same time, the residual stress distribution has been investigated in detail.

Barriers in Sustainable Knowledge Management Model in Education

Directory of Open Access Journals (Sweden)

Gratiela Dana BOCA

2016-12-01

Full Text Available The paper present a comprehensive model in education using the data base collected from 101 students from Turkey. The target group was students involved in academic life system. Results are used to design a model where education transfer of knowledge it is investigated in function of possible barriers as internal, external and knowledge management factors of influence in education selection and students vision for education development. As a conclusion, the evaluation of the barriers in sustainable knowledge management in education present a cross-educational model which seems to indicate its highly effective resource for environmental education focused on sustainability, and favours the development of knowledge, attitudes and future intentions of inspiring educational environment. The model can be useful on passing of knowledge from one generation to the next generation, managing succession and distributing the competencies and responsibilities to a repetitive change.

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).

Development of a continuous motorcycle protection barrier system using computer simulation and full-scale crash testing.

Science.gov (United States)

Atahan, Ali O; Hiekmann, J Marten; Himpe, Jeffrey; Marra, Joseph

2018-07-01

Road restraint systems are designed to minimize the undesirable effects of roadside accidents and improve safety of road users. These systems are utilized at either side or median section of roads to contain and redirect errant vehicles. Although restraint systems are mainly designed against car, truck and bus impacts there is an increasing pressure by the motorcycle industry to incorporate motorcycle protection systems into these systems. In this paper development details of a new and versatile motorcycle barrier, CMPS, coupled with an existing vehicle barrier is presented. CMPS is intended to safely contain and redirect motorcyclists during a collision event. First, crash performance of CMPS design is evaluated by means of a three dimensional computer simulation program LS-DYNA. Then full-scale crash tests are used to verify the acceptability of CMPS design. Crash tests were performed at CSI proving ground facility using a motorcycle dummy in accordance with prEN 1317-8 specification. Full-scale crash test results show that CMPS is able to successfully contain and redirect dummy with minimal injury risk on the dummy. Damage on the barrier is also minimal proving the robustness of the CMPS design. Based on the test findings and further review by the authorities the implementation of CMPS was recommended at highway system. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Internal resistor of multi-functional tunnel barrier for selectivity and switching uniformity in resistive random access memory.

Science.gov (United States)

Lee, Sangheon; Woo, Jiyong; Lee, Daeseok; Cha, Euijun; Hwang, Hyunsang

2014-01-01

In this research, we analyzed the multi-functional role of a tunnel barrier that can be integrated in devices. This tunnel barrier, acting as an internal resistor, changes its resistance with applied bias. Therefore, the current flow in the devices can be controlled by a tunneling mechanism that modifies the tunnel barrier thickness for non-linearity and switching uniformity of devices. When a device is in a low-resistance state, the tunnel barrier controls the current behavior of the device because most of the bias is applied to the tunnel barrier owing to its higher resistance. Furthermore, the tunnel barrier induces uniform filament formation during set operation with the tunnel barrier controlling the current flow.

Combined photovoltaic and solar-thermal systems: overcoming barriers to market acceptance

International Nuclear Information System (INIS)

Collins, M.R.

2005-01-01

Combined Photovoltaic and Solar-Thermal Systems (PV/T Systems) combine Photovoltaic (PV) and solar thermal technologies into one system with both electrical and thermal energy output. PV/T systems have several perceived advantages to stand-alone PV or solar-thermal systems. The increased efficiency and dual nature of the systems make suitable for situations where installation space is limited, and for homeowners who are forced to decide between meeting thermal or electrical needs. The financial benefit of the combined system is also significant, as the long payback of PV systems is joined with a relatively short payback of solar thermal systems. A background of PV/T was presented, with details of classifications and the International Energy Association's program to evaluate the technical status of PV/T systems and formulate a roadmap for future development. It was noted that input from the Solar Heating and Cooling Program (SHCP) is needed to help identify market barriers in PV/T systems. This paper reviewed existing and potential PV/T systems and their technical status, and reported on the methodology established by IEA group 35. The systems were grouped according to thermal collector types of unglazed water collectors, glazed water collectors, unglazed air collectors, glazed air collectors, air-flow windows, and concentrating collectors. It was noted that a number of new systems are currently being developed, including concentrating collectors with water and air heating, unglazed air heating systems, and unglazed water heating systems. It was noted that apart from technical barriers, efficient design and performance prediction are also problematic, as tools for predicting performance do not exist. The same tools will be used to optimize PV/T system designs. It was suggested that standardized reporting methods, simulation and sizing tools and demonstration products need to be created and that regional certification issues need to be identified. Environmental

Microscopic study on dynamic barrier in fusion reactions

International Nuclear Information System (INIS)

Wu Xizhen; Tian Junlong; Zhao Kai; Li Zhuxia; Wang Ning

2004-01-01

The authors briefly review the fusion process of very heavy nuclear systems and some theoretical models. The authors propose a microscopic transport dynamic model, i.e. the Improved Quantum Molecular Dynamic model, for describing fusion reactions of heavy systems, in which the dynamical behavior of the fusion barrier in heavy fusion systems has been studied firstly. The authors find that with the incident energy decreasing the lowest dynamic barrier is obtained which approaches to the adiabatic static barrier and with increase of the incident energy the dynamic barrier goes up to the diabatic static barrier. The authors also indicate that how the dynamical fusion barrier is correlated with the development of the configuration of fusion partners along the fusion path. Associating the single-particle potentials obtained at different stages of fusion with the Two Center Shell Model, authors can study the time evolution of the single particle states of fusion system in configuration space of single particle orbits along the fusion path. (author)

Coupled channel effects in quasi-elastic barrier distributions of 16,18O + 206Pb systems

International Nuclear Information System (INIS)

Jha, V.; Roy, B.J.; Parkar, V.V.; Kumawat, H.; Pal, U.K.; Pandit, S.K.; Mahata, K.; Shrivastava, A.; Mohanty, A.K.

2013-01-01

The fusion barrier distribution and QEBD for the 16 O + 208 Pb have been studied in great detail. The couplings due to the collective excitations of the colliding nuclei are found to have the dominant effect as deduced by the conventional coupled-channels calculations used to explain the experimental QEBD and fusion barrier distributions. In contrast, for the 18 O + 206 Pb system, the role of single neutron stripping (Q-value= -1.308 MeV) and neutron pair transfer (Q-value = + 1.917 MeV) are expected to be significant. In the present work, the QEBD measurements for the 18 O + 206 Pb system are performed for the investigation of these aspects

Integrated modelling of near field and engineered barrier system processes

International Nuclear Information System (INIS)

Lamont, A.; Gansemer, J.

1994-01-01

The Yucca Mountain Integrating Model (YMIM) is an integrated model of the Engineered barrier System has been developed to assist project managers at LLNL in identifying areas where research emphasis should be placed. The model was designed to be highly modular so that a model of an individual process could be easily modified or replaced without interfering with the models of other processes. The modules modelling container failure and the dissolution of nuclides include particularly detailed, temperature dependent models of their corresponding processes

Barriers to breast cancer screening among a sample of Egyptian females

Directory of Open Access Journals (Sweden)

Heba M. Mamdouh

2014-01-01

Full Text Available Background: Breast cancer (BC is usually diagnosed in late stages in countries with limited resources. Early detection of BC is likely to improve the outcome of the disease for women in these areas. Objective: The aim of this study was to understand the possible personal, economic, and systems barriers to BC screening in a sample of Egyptian women. Materials and Methods: A cross-sectional study was conducted in family health centers representing the seven districts of Alexandria governorate, Egypt. A total of 612 women were randomly selected from the chosen centers. Results: In this sample of Egyptian women, the most frequently identified potential barriers to BC screening were the following: 81.8% would not seek care until they were ill, 77% were unwilling to have a mammogram until it was recommended by the doctor, 71.4% blamed the, lack of privacy, 69.2% thought that medical checkups were not worthwhile, and 64.6% blamed the cost of services. The study further revealed that women of lower education, women in the lower income category, women who did not do paid work, those who had poor knowledge of the risks of BC, and women with no family history of BC were more likely to perceive different screening barriers compared with their counterparts. Conclusion: Many potential personal, economic, and health system barriers were identified. Addressing these barriers by increasing the awareness of BC and dealing with the misconceptions that the women have can help the policy makers to design more culturally relevant strategies to motivate women to utilize screening services.

A Study of the Bolt Connection System for a Concrete Barrier of a Modular Bridge

Directory of Open Access Journals (Sweden)

Doo-Yong Cho

2018-04-01

Full Text Available Modular technology has been recently studied to reduce the construction periods in the field of bridge construction. However, this method is restricted to the pier, girder, and deck, which are the main members of a bridge, and incidental facilities such as concrete barriers have been rarely studied. Thus, in this study, the connection system of a concrete barrier for modular bridges was developed, and a static loading experiment was performed to verify the structural capacity of the proposed system. The variables of the experiment were the vertical and horizontal bolt connections and the construction method. The barrier and plate were fabricated using match casting methods in which nuts were first inserted into the plates rather than anchor bolts using the conservative method. Moreover, a comparison with the conventional in situ barrier was also performed. The experiments were conducted according to the AASHTO LRFD standard. Consequently, the specimen using the vertical bolt connection had a structural capacity that was equal to 85% of that of the conventional specimen and exhibited similar crack patterns compared with the conventional specimen. In the case of the horizontal bolt connection, the separation in the connection area occurred with the application of the initial load and this specimen exhibited a poor performance because of the increase in the separation distance with the application of the maximum load.

Next generation of non-mammalian blood-brain barrier models to study parasitic infections of the central nervous system

OpenAIRE

Siddiqui, Ruqaiyyah; Edwards-Smallbone, James; Flynn, Robin; Khan, Naveed Ahmed

2012-01-01

Transmigration of neuropathogens across the blood-brain barrier is a key step in the development of central nervous system infections, making it a prime target for drug development. The ability of neuropathogens to traverse the blood-brain barrier continues to inspire researchers to understand the specific strategies and molecular mechanisms that allow them to enter the brain. The availability of models of the blood-brain barrier that closely mimic the situation in vivo offers unprecedented o...

Barriers to Liposomal Gene Delivery: from Application Site to the Target.

Science.gov (United States)

Saffari, Mostafa; Moghimi, Hamid Reza; Dass, Crispin R

2016-01-01

Gene therapy is a therapeutic approach to deliver genetic material into cells to alter their function in entire organism. One promising form of gene delivery system (DDS) is liposomes. The success of liposome-mediated gene delivery is a multifactorial issue and well-designed liposomal systems might lead to optimized gene transfection particularly in vivo. Liposomal gene delivery systems face different barriers from their site of application to their target, which is inside the cells. These barriers include presystemic obstacles (epithelial barriers), systemic barriers in blood circulation and cellular barriers. Epithelial barriers differ depending on the route of administration. Systemic barriers include enzymatic degradation, binding and opsonisation. Both of these barriers can act as limiting hurdles that genetic material and their vector should overcome before reaching the cells. Finally liposomes should overcome cellular barriers that include cell entrance, endosomal escape and nuclear uptake. These barriers and their impact on liposomal gene delivery will be discussed in this review.

The socio-technical barriers to Solar Home Systems (SHS) in Papua New Guinea: 'Choosing pigs, prostitutes, and poker chips over panels'

International Nuclear Information System (INIS)

Sovacool, Benjamin K.; D'Agostino, Anthony L.; Jain Bambawale, Malavika

2011-01-01

This study explores the socio-technical barriers to Solar Home Systems (SHS) in Papua New Guinea. The authors collected primary data through semi-structured research interviews conducted over the course of February 2010-April 2010. Respondents included government officials, financiers, planners, commercial distributors and companies, teachers and rural villagers in addition to members of civil society, academics, consultants, and trainers. These interviews were supplemented with site visits to Port Moresby, Goroka, and Madang, and field research in the villages of Akameku, Asaroka, Lufa, Kundiawa, Okifa, Simbu, and Talidig. The study draws from these interviews and visits to discuss four types of barriers. Technical barriers relate to substandard equipment and logistical problems. Economic barriers include high rates of poverty, misconceptions about the role of currency, and lack of financing. Political barriers include poor institutional capacity and a government commitment to fossil-fueled grid electrification. Social barriers encompass unrealistic expectations about what SHS can provide along with jealousy, theft, vandalism, and unfamiliarity with solar technology. - Research highlights: → Solar Home Systems (SHS) are impeded by a collection of different barriers in Papua New Guinea. → Technical barriers relate to substandard equipment and logistical problems. → Economic barriers include high rates of poverty, misconceptions about the role of currency, and lack of financing.→ Political barriers include poor institutional capacity and a government commitment to fossil-fueled grid electrification. → Social barriers encompass unrealistic expectations about what SHS can provide along with jealousy, theft, vandalism, and unfamiliarity with solar technology.

The Blood-Brain Barrier: Connecting the Gut and the Brain

OpenAIRE

Banks, William A.

2008-01-01

The BBB prevents the unrestricted exchange of substances between the central nervous system (CNS) and the blood. The blood-brain barrier (BBB) also conveys information between the CNS and the gastrointestinal (GI) tract through several mechanisms. Here, we review three of those mechanisms. First, the BBB selectively transports some peptides and regulatory proteins in the blood-to-brain or the brain-to-blood direction. The ability of GI hormones to affect functions of the BBB, as illustrated b...

Modelling the endothelial blood-CNS barriers: a method for the production of robust in vitro models of the rat blood-brain barrier and blood-spinal cord barrier.

Science.gov (United States)

Watson, P Marc D; Paterson, Judy C; Thom, George; Ginman, Ulrika; Lundquist, Stefan; Webster, Carl I

2013-06-18

Modelling the blood-CNS barriers of the brain and spinal cord in vitro continues to provide a considerable challenge for research studying the passage of large and small molecules in and out of the central nervous system, both within the context of basic biology and for pharmaceutical drug discovery. Although there has been considerable success over the previous two decades in establishing useful in vitro primary endothelial cell cultures from the blood-CNS barriers, no model fully mimics the high electrical resistance, low paracellular permeability and selective influx/efflux characteristics of the in vivo situation. Furthermore, such primary-derived cultures are typically labour-intensive and generate low yields of cells, limiting scope for experimental work. We thus aimed to establish protocols for the high yield isolation and culture of endothelial cells from both rat brain and spinal cord. Our aim was to optimise in vitro conditions for inducing phenotypic characteristics in these cells that were reminiscent of the in vivo situation, such that they developed into tight endothelial barriers suitable for performing investigative biology and permeability studies. Brain and spinal cord tissue was taken from the same rats and used to specifically isolate endothelial cells to reconstitute as in vitro blood-CNS barrier models. Isolated endothelial cells were cultured to expand the cellular yield and then passaged onto cell culture inserts for further investigation. Cell culture conditions were optimised using commercially available reagents and the resulting barrier-forming endothelial monolayers were characterised by functional permeability experiments and in vitro phenotyping by immunocytochemistry and western blotting. Using a combination of modified handling techniques and cell culture conditions, we have established and optimised a protocol for the in vitro culture of brain and, for the first time in rat, spinal cord endothelial cells. High yields of both CNS

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

Changes in skin barrier during treatment with systemic alitretinoin: focus on skin susceptibility and stratum corneum ceramides

DEFF Research Database (Denmark)

Jungersted, J.M.; Høgh, Julie Kaae; Hellgren, Lars

2010-01-01

) was performed on the volar forearm and evaluated by trans-epidermal water loss (TEWL), erythema, and a cyanoacrylate skin sample was obtained for lipid analysis. We found no significant changes in response to SLS irritation as evaluated by TEWL and erythema, after treatment with alitretinoin for 2 months......Alitretinoin is a new drug for systemic treatment of chronic hand eczema. Previous functional tests of skin topically treated with retinoids have indicated impaired skin barrier function, but no data are available on barrier parameters after systemic alitretinoin treatment. To investigate...

Containment analysis of the 9975 transportation package with multiple barriers

International Nuclear Information System (INIS)

Vinson, D.W.

2000-01-01

A containment analysis has been performed for the scenario of non-routine transfer of a damaged 9975 package containing plutonium metal from K-area monitored storage to F-area on the Savannah River Site. A multiple barrier system with each barrier having a defined leakage rate of less than 1times10 -3 cm 3 /sec of air at Standard Temperature and Pressure was analyzed to determine the number of barriers needed to transport the package under normal transportation conditions to meet transportation requirements for containment. The barrier system was analyzed parametrically to achieve a composite system that met the federal requirements for the maximum permissible release rate given in Title 10 of the Code of Federal Regulations, Part 71. The multiple barrier system acts to retard the release of radioactivity. That is, a build-up in the radioactivity release rate occurs with time. For example, a system with three barriers (e.g., sealed plastic barrier) with a total free volume of 4,500 cm 3 could be transported for a total time of up to approximately 10 days with a release rate within the permissible rate. Additional number of barriers, or volume of the barriers, or both, would extend to this period of time. For example, a system with seven barriers with a total free volume of 4,500 cm 3 could be transported for up to 100 days. Plastic bags are one type of barrier used in movement of radioactive materials and capable of achieving a leak rate of 1times10 -3 cm 3 /sec of air at STP. Low-density polyethylene bags can withstand high temperature (up to 180 degrees C); a barrier thickness of 10 mils should be suitable for the barrier system. Additional requirements for barriers are listed in Section 4.2 of this report. Container testing per ANSI N14.5 is required to demonstrate leak rates for the individual barriers of less than 1times10 -3 cm 3 /sec

Band-selective filter in a zigzag graphene nanoribbon.

Science.gov (United States)

Nakabayashi, Jun; Yamamoto, Daisuke; Kurihara, Susumu

2009-02-13

Electric transport of a zigzag graphene nanoribbon through a steplike potential and a barrier potential is investigated by using the recursive Green's function method. In the case of the steplike potential, we demonstrate numerically that scattering processes obey a selection rule for the band indices when the number of zigzag chains is even; the electrons belonging to the "even" ("odd") bands are scattered only into the even (odd) bands so that the parity of the wave functions is preserved. In the case of the barrier potential, by tuning the barrier height to be an appropriate value, we show that it can work as the "band-selective filter", which transmits electrons selectively with respect to the indices of the bands to which the incident electrons belong. Finally, we suggest that this selection rule can be observed in the conductance by applying two barrier potentials.

Technique Selectively Represses Immune System

Science.gov (United States)

... Research Matters December 3, 2012 Technique Selectively Represses Immune System Myelin (green) encases and protects nerve fibers (brown). A new technique prevents the immune system from attacking myelin in a mouse model of ...

Edge transport barrier formation in compact helical system

International Nuclear Information System (INIS)

Okamura, S; Minami, T; Oishi, T; Suzuki, C; Ida, K; Isobe, M; Yoshimura, Y; Nagaoka, K; Toi, K; Fujisawa, A; Akiyama, T; Iguchi, H; Ikeda, R; Kado, S; Matsuoka, K; Matsushita, H; Nakamura, K; Nakano, H; Nishimura, S; Nishiura, M; Ohshima, S; Shimizu, A; Takagi, S; Takahashi, C; Takeuchi, M; Yoshinuma, M

2004-01-01

The edge transport barrier (ETB) for particle transport is formed in the neutral beam (NB) heated hydrogen discharges in compact helical system (CHS). The transition to the ETB formation and the back transition are controlled by the heating power. The existence of the heating power threshold is confirmed and it is roughly proportional to the density. The Hα emission signal shows a clear drop at the transition (the timescale of signal decrease is ∼1 ms for the high heating power case). The ETB formation continues for the full duration of NB injection (100 ms) with a moderate level of radiation power loss. Local density profile measurement shows increase of the edge density and the movement of the density gradient region towards the edge

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

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.

Organizational human factors as barriers to energy efficiency in electrical motors systems in industry

International Nuclear Information System (INIS)

Sola, Antonio Vanderley Herrero; Augusto de Paula, Xavier Antonio

2007-01-01

This paper presents a study accomplished in the State of Parana in Southern Brazil, aiming at verifying the correlation between organizational human factors (OHF) and the level of energy losses in organizations. The purpose is to subsidize the formularization of institutional policies in organizations to improve the energy efficiency in the productive sector. The research was carried out in ten industries of the following sectors: pulp and paper; food; wood and chemical products. The losses of electric energy were determined in motor systems with the aid of a mathematical model and the evaluation of 27 OHF identified in the literature review was made with the supervisors in the industries by means of a structurized questionnaire. Seven OHF had presented significant correlation with energy losses and six of them are inversely proportional to the losses, in accordance with linear regression analysis. The inversely proportional factors to the losses also with significant correlation are considered determinative OHF and constitute barriers for energy efficiency in organizations. These barriers are linked with the following organizational areas: management system; education of employees; strategical vision. The study recommends the implementation of the determinative OHF in organizations as a way to transpose the human barriers for energy efficiency

Isotopic effects in sub-barrier fusion of Si + Si systems

Science.gov (United States)

Colucci, G.; Montagnoli, G.; Stefanini, A. M.; Esbensen, H.; Bourgin, D.; Čolović, P.; Corradi, L.; Faggian, M.; Fioretto, E.; Galtarossa, F.; Goasduff, A.; Grebosz, J.; Haas, F.; Mazzocco, M.; Scarlassara, F.; Stefanini, C.; Strano, E.; Szilner, S.; Urbani, M.; Zhang, G. L.

2018-04-01

Background: Recent measurements of fusion cross sections for the 28Si+28Si system revealed a rather unsystematic behavior; i.e., they drop faster near the barrier than at lower energies. This was tentatively attributed to the large oblate deformation of 28Si because coupled-channels (CC) calculations largely underestimate the 28Si+28Si cross sections at low energies, unless a weak imaginary potential is applied, probably simulating the deformation. 30Si has no permanent deformation and its low-energy excitations are of a vibrational nature. Previous measurements of this system reached only 4 mb, which is not sufficient to obtain information on effects that should show up at lower energies. Purpose: The aim of the present experiment was twofold: (i) to clarify the underlying fusion dynamics by measuring the symmetric case 30Si+30Si in an energy range from around the Coulomb barrier to deep sub-barrier energies, and (ii) to compare the results with the behavior of 28Si+28Si involving two deformed nuclei. Methods: 30Si beams from the XTU tandem accelerator of the Laboratori Nazionali di Legnaro of the Istituto Nazionale di Fisica Nucleare were used, bombarding thin metallic 30Si targets (50 μ g /cm2) enriched to 99.64 % in mass 30. An electrostatic beam deflector allowed the detection of fusion evaporation residues (ERs) at very forward angles, and angular distributions of ERs were measured. Results: The excitation function of 30Si+30Si was measured down to the level of a few microbarns. It has a regular shape, at variance with the unusual trend of 28Si+28Si . The extracted logarithmic derivative does not reach the LCS limit at low energies, so that no maximum of the S factor shows up. CC calculations were performed including the low-lying 2+ and 3- excitations. Conclusions: Using a Woods-Saxon potential the experimental cross sections at low energies are overpredicted, and this is a clear sign of hindrance, while the calculations performed with a M3Y + repulsion

Engineered Barrier System - Manufacturing, Testing and Quality Assurance. Report from a Workshop

International Nuclear Information System (INIS)

2004-06-01

As part of preparations for review of future license applications, the Swedish Nuclear Power Inspectorate (SKI) organised a workshop on the engineered barrier system for the KBS-3 concept, with the focus on manufacturing, testing and quality assurance. The main purpose of the workshop was to identify critical issues in the demonstration of how long-term safety requirements could be fulfilled for the engineered barriers. The workshop included presentations related to engineered barrier manufacturing and testing held by external experts, and working group sessions to prepare questions to the Swedish Nuclear Fuel and Waste Management Co. (SKB). SKB presentations were followed by an informal questioning and discussion with SKB representatives. This report includes a presentation of the questions posed by the working groups, SKB's replies to these questions as well as a summary of the working group discussions. The conclusions and viewpoints presented in this report are those of one or several workshop participants. During the workshop many issues regarding manufacturing, testing and quality assurance of the engineered barriers were discussed. The central themes in the questions and discussions are summarised as follows: There is a need to specify how the functional requirements for the buffer and backfill will be achieved in practise. Issues of particular interest are material selection, compaction density, initial water content and manufacturing methods for bentonite blocks. A major problem that must be addressed is the long period required to obtain relevant results from large-scale testing. The uncertainties relating to the wetting and subsequent swelling processes of the bentonite buffer have implications for analysis of the canister. It is necessary to know now non-uniform the bentonite swelling pressure could be in a worst case pressure differential, in order to evaluate the sufficiency of 'as tested' canister performance. Regarding the copper shell of the

Zebrafish as a visual and dynamic model to study the transport of nanosized drug delivery systems across the biological barriers.

Science.gov (United States)

Li, Ye; Miao, Xiaoqing; Chen, Tongkai; Yi, Xiang; Wang, Ruibing; Zhao, Haitao; Lee, Simon Ming-Yuen; Wang, Xueqing; Zheng, Ying

2017-08-01

With the wide application of nanotechnology to drug delivery systems, a simple, dynamic and visual in vivo model for high-throughput screening of novel formulations with fluorescence markers across biological barriers is desperately needed. In vitro cell culture models have been widely used, although they are far from a complimentary in vivo system. Mammalian animal models are common predictive models to study transport, but they are costly and time consuming. Zebrafish (Danio rerio), a small vertebrate model, have the potential to be developed as an "intermediate" model for quick evaluations. Based on our previously established coumarin 6 nanocrystals (C6-NCs), which have two different sizes, the present study investigates the transportation of C6-NCs across four biological barriers, including the chorion, blood brain barrier (BBB), blood retinal barrier (BRB) and gastrointestinal (GI) barrier, using zebrafish embryos and larvae as in vivo models. The biodistribution and elimination of C6 from different organs were quantified in adult zebrafish. The results showed that compared to 200nm C6-NCs, 70nm C6-NCs showed better permeability across these biological barriers. A FRET study suggested that intact C6-NCs together with the free dissolved form of C6 were absorbed into the larval zebrafish. More C6 was accumulated in different organs after incubation with small sized NCs via lipid raft-mediated endocytosis in adult zebrafish, which is consistent with the findings from in vitro cell monolayers and the zebrafish larvae model. C6-NCs could be gradually eliminated in each organ over time. This study demonstrated the successful application of zebrafish as a simple and dynamic model to simultaneously assess the transport of nanosized drug delivery systems across several biological barriers and biodistribution in different organs, especially in the brain, which could be used for central nervous system (CNS) drug and delivery system screening. Copyright © 2017 Elsevier B

Next generation of non-mammalian blood-brain barrier models to study parasitic infections of the central nervous system

Science.gov (United States)

Siddiqui, Ruqaiyyah; Edwards-Smallbone, James; Flynn, Robin; Khan, Naveed Ahmed

2012-01-01

Transmigration of neuropathogens across the blood-brain barrier is a key step in the development of central nervous system infections, making it a prime target for drug development. The ability of neuropathogens to traverse the blood-brain barrier continues to inspire researchers to understand the specific strategies and molecular mechanisms that allow them to enter the brain. The availability of models of the blood-brain barrier that closely mimic the situation in vivo offers unprecedented opportunities for the development of novel therapeutics. PMID:21921682

Laboratory and field scale demonstration of reactive barrier systems

International Nuclear Information System (INIS)

Dwyer, B.P.; Marozas, D.C.; Cantrell, K.; Stewart, W.

1996-10-01

In an effort to devise a cost efficient technology for remediation of uranium contaminated groundwater, the Department of Energy's Uranium Mill Tailings Remedial Action (DOE-UMTRA) Program through Sandia National Laboratories (SNL) fabricated a pilot scale research project utilizing reactive subsurface barriers at an UMTRA site in Durango, Colorado. A reactive subsurface barrier is produced by placing a reactant material (in this experiment, metallic iron) in the flow path of the contaminated groundwater. The reactive media then removes and/or transforms the contaminant(s) to regulatory acceptable levels. Experimental design and results are discussed with regard to other potential applications of reactive barrier remediation strategies at other sites with contaminated groundwater problems

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

Role of Geologic Framework, Paleotopography, Sediment Supply, and Human Modification in the Evolutionary Development of the Northeastern North Carolina Barrier Island System

Science.gov (United States)

Riggs, S. R.; Thieler, E. R.; Mallinson, D. A.; Culver, S. J.; Corbett, D. R.; Hoffman, C. W.

2002-12-01

The NE North Carolina coastal system contains an exceptionally thick and well preserved Quaternary stratigraphic record that is the focus of a five-year Cooperative Coastal Geology Program between the USGS, several academic institutions, and state agencies. The major goal is to map this Quaternary section on the inner continental shelf, Outer Banks barrier islands, Albemarle-Pamlico estuarine system, and adjacent land areas. The program objectives are to define the geologic framework, develop the detailed evolutionary history, and understand the ongoing process dynamics driving this large, complex, and rapidly changing, high-energy coastal system. Preliminary data synthesis demonstrates that the major controls dictating the present health and future evolution of this coastal system include the following. 1) The regional late Pleistocene morphology constitutes the underlying geologic framework that the Holocene system has inherited. 2) The controlling paleotopography is a series of lowstand drainage basins consisting of trunk and tributary streams and associated interstream divides that are being drowned. 3) Three major sediment sources dictate the highly variable sand resources available to specific barrier segments and include riverine channel and deltaic deposits associated with lowstand trunk streams, the large cross-shelf cape shoal sand deposits, and sand-rich units occurring within the adjacent shoreface and inner-self strata. 4) Wherever large sand supplies have historically been available, the barrier segments occur as complex islands with large sand volumes producing high and wide barriers, whereas barrier segments without adequate sand supplies are sediment starved and occur as simple overwash barriers. 5) Human modification of the barrier islands over the past seven decades represents a major force that has significantly changed the barrier island dynamics and evolution. 6) The Albemarle Embayment appears to have a slightly higher rate of sea-level rise

Selecting a Cable System Operator.

Science.gov (United States)

Cable Television Information Center, Washington, DC.

Intended to assist franchising authorities with the process of selecting a cable television system operator from franchise applicants, this document provides a framework for analysis of individual applications. Section 1 deals with various methods which can be used to select an operator. The next section covers the application form, the vehicle a…

Controlling surface adsorption to enhance the selectivity of porphyrin based gas sensors

Energy Technology Data Exchange (ETDEWEB)

Evyapan, M., E-mail: mevyapan@gmail.com [Department of Physics, University of Balikesir, Balikesir, 10145 (Turkey); Chemical and Biological Engineering, University of Sheffield, Mappin Building, S1 3JD (United Kingdom); Dunbar, A.D.F. [Chemical and Biological Engineering, University of Sheffield, Mappin Building, S1 3JD (United Kingdom)

2016-01-30

specific ratios in order to control the selectivity of the resulting barrier layers. Spectroscopic Ellipsometry (SE) and Atomic Force Microscopy (AFM) measurements were carried out to analyze the structure of the porous barrier layers. It was found that the orientation of the calix[8]arene molecules was well controlled within the Langmuir layers such that molecular ring lies flat on the EHO layers when deposited. However, the calix[6]arene and calix[4]arene molecules were quite not so reliably oriented. The sensor films (with and without the addition of the different selective barrier layers) were exposed to various carboxylic acid vapors. More specifically, acetic acid, butyric acid and hexanoic acid were chosen due to their different molecular sizes. The uncovered EHO films were highly sensitive to all the carboxylic acids. The porosity of the barrier layers which influences their selectivity was investigated by changing the size of the acid molecules. Upon deposition of a barrier layer on top of EHO film the sensing response rate and magnitude were changed depending on both the barrier layer structure and molecular size of the analyte vapor. The optical sensing results show that by controlling the size of the pores in the barrier layer it can be used as a size selective layer which limits the diffusion of analyte molecules into the sensor and in extreme cases stopping the diffusion completely. Therefore the selectivity of this sensor system has been enhanced by adding a controllable barrier layer. The enhanced sensors have been used to differentiate between acetic, butyric and hexanoic acids.

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

Safety performance evaluation of cable median barriers on freeways in Florida.

Science.gov (United States)

Alluri, Priyanka; Haleem, Kirolos; Gan, Albert; Mauthner, John

2016-07-03

This article aims to evaluate the safety performance of cable median barriers on freeways in Florida. The safety performance evaluation was based on the percentages of barrier and median crossovers by vehicle type, crash severity, and cable median barrier type (Trinity Cable Safety System [CASS] and Gibraltar system). Twenty-three locations with cable median barriers totaling about 101 miles were identified. Police reports of 6,524 crashes from years 2005-2010 at these locations were reviewed to verify and obtain detailed crash information. A total of 549 crashes were determined to be barrier related (i.e., crashes involving vehicles hitting the cable median barrier) and were reviewed in further detail to identify crossover crashes and the manner in which the vehicles crossed the barriers; that is, by either overriding, underriding, or penetrating the barriers. Overall, 2.6% of vehicles that hit the cable median barrier crossed the median and traversed into the opposite travel lane. Overall, 98.1% of cars and 95.5% of light trucks that hit the barrier were prevented from crossing the median. In other words, 1.9% of cars and 4.5% of light trucks that hit the barrier had crossed the median and encroached on the opposite travel lanes. There is no significant difference in the performance of cable median barrier for cars versus light trucks in terms of crossover crashes. In terms of severity, overrides were more severe compared to underrides and penetrations. The statistics showed that the CASS and Gibraltar systems performed similarly in terms of crossover crashes. However, the Gibraltar system experienced a higher proportion of penetrations compared to the CASS system. The CASS system resulted in a slightly higher percentage of moderate and minor injury crashes compared to the Gibraltar system. Cable median barriers are successful in preventing median crossover crashes; 97.4% of the cable median barrier crashes were prevented from crossing over the median. Of all of

International Collaboration Activities on Engineered Barrier Systems

Energy Technology Data Exchange (ETDEWEB)

Jove-Colon, Carlos F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-08-31

The Used Fuel Disposition Campaign (UFDC) within the DOE Fuel Cycle Technologies (FCT) program has been engaging in international collaborations between repository R&D programs for high-level waste (HLW) disposal to leverage on gathered knowledge and laboratory/field data of near- and far-field processes from experiments at underground research laboratories (URL). Heater test experiments at URLs provide a unique opportunity to mimetically study the thermal effects of heat-generating nuclear waste in subsurface repository environments. Various configurations of these experiments have been carried out at various URLs according to the disposal design concepts of the hosting country repository program. The FEBEX (Full-scale Engineered Barrier Experiment in Crystalline Host Rock) project is a large-scale heater test experiment originated by the Spanish radioactive waste management agency (Empresa Nacional de Residuos Radiactivos S.A. – ENRESA) at the Grimsel Test Site (GTS) URL in Switzerland. The project was subsequently managed by CIEMAT. FEBEX-DP is a concerted effort of various international partners working on the evaluation of sensor data and characterization of samples obtained during the course of this field test and subsequent dismantling. The main purpose of these field-scale experiments is to evaluate feasibility for creation of an engineered barrier system (EBS) with a horizontal configuration according to the Spanish concept of deep geological disposal of high-level radioactive waste in crystalline rock. Another key aspect of this project is to improve the knowledge of coupled processes such as thermal-hydro-mechanical (THM) and thermal-hydro-chemical (THC) operating in the near-field environment. The focus of these is on model development and validation of predictions through model implementation in computational tools to simulate coupled THM and THC processes.

Selective effects of alpha-MSH and MIF-1 on the blood-brain barrier

International Nuclear Information System (INIS)

Sankar, R.; Domer, F.R.; Kastin, A.J.

1981-01-01

The effects of intravenously-injected alpha-MSH and MIF-1 (Pro-Leu-Gly-NH2) on the permeability of the blood-brain barrier (BBB) to a large protein and a small anion were studied using radioiodinated serum albumin (RISA) and 99mTc-labeled sodium pertechnetate. The permeability of the BBB to RISA was unaltered by either peptide. Permeability to the inorganic pertechnetate anion, however, was significantly increased by alpha-MSH but not by MIF-1 at doses known to evoke EEG and behavioral responses. The peptides did not cause a change in the systemic blood pressure. It is possible, therefore, that at least some CNS effects of peripherally administered peptides are exerted by alteration of the permeability of the BBB to other substances

Creep Behavior of Hafnia and Ytterbium Silicate Environmental Barrier Coating Systems on SiC/SiC Ceramic Matrix Composites

Science.gov (United States)

Zhu, Dongming; Fox, Dennis S.; Ghosn, Louis J.; Harder, Bryan

2011-01-01

Environmental barrier coatings will play a crucial role in future advanced gas turbine engines because of their ability to significantly extend the temperature capability and stability of SiC/SiC ceramic matrix composite (CMC) engine components, thus improving the engine performance. In order to develop high performance, robust coating systems for engine components, appropriate test approaches simulating operating temperature gradient and stress environments for evaluating the critical coating properties must be established. In this paper, thermal gradient mechanical testing approaches for evaluating creep and fatigue behavior of environmental barrier coated SiC/SiC CMC systems will be described. The creep and fatigue behavior of Hafnia and ytterbium silicate environmental barrier coatings on SiC/SiC CMC systems will be reported in simulated environmental exposure conditions. The coating failure mechanisms will also be discussed under the heat flux and stress conditions.

Effective selection of transgenic papaya plants with the PMI/Man selection system.

Science.gov (United States)

Zhu, Yun J; Agbayani, Ricelle; McCafferty, Heather; Albert, Henrik H; Moore, Paul H

2005-09-01

The selectable marker gene phospho-mannose isomerase (pmi), which encodes the enzyme phospho-mannose isomerase (PMI) to enable selection of transformed cell lines on media containing mannose (Man), was evaluated for genetic transformation of papaya (Carica papaya L.). We found that papaya embryogenic calli have little or no PMI activity and cannot utilize Man as a carbon source; however, when calli were transformed with a pmi gene, the PMI activity was greatly increased and they could utilize Man as efficiently as sucrose. Plants regenerated from selected callus lines also exhibited PMI activity but at a lower specific activity level. Our transformation efficiency with Man selection was higher than that reported using antibiotic selection or with a visual marker. For papaya, the PMI/Man selection system for producing transgenic plants is a highly efficient addition to previously published methods for selection and may facilitate the stacking of multiple transgenes of interest. Additionally, since the PMI/Man selection system does not involve antibiotic or herbicide resistance genes, its use might reduce environmental concerns about the potential flow of those genes into related plant populations.

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

Discursive barriers and cross-scale forest governance in Central Kalimantan, Indonesia

Directory of Open Access Journals (Sweden)

Caleb T. Gallemore

2014-06-01

Full Text Available Students of social-ecological systems have emphasized the need for effective cross-scale governance. We theorized that discursive barriers, particularly between technical and traditional practices, can act as a barrier to cross-scale collaboration. We analyzed the effects of discursive divides on collaboration on Reducing Emissions from Deforestation and Forest Degradation (REDD+ policy development in Central Kalimantan, an Indonesian province on the island of Borneo selected in 2010 to pilot subnational REDD+ policy. We argue that the complexities of bridging local land management practices and technical approaches to greenhouse gas emissions reduction and carbon offsetting create barriers to cross-scale collaboration. We tested these hypotheses using an exponential random graph model of collaboration among 36 organizations active in REDD+ policy in the province. We found that discursive divides were associated with a decreased probability of collaboration between organizations and that organizations headquartered outside the province were less likely to collaborate with organizations headquartered in the province. We conclude that bridging discursive communities presents a chicken-and-egg problem for cross-scale governance of social-ecological systems. In precisely the situations where it is most important, when bridging transnational standards with local knowledge and land management practices, it is the most difficult.

Culture media-based selection of endothelial cells, pericytes, and perivascular-resident macrophage-like melanocytes from the young mouse vestibular system.

Science.gov (United States)

Zhang, Jinhui; Chen, Songlin; Cai, Jing; Hou, Zhiqiang; Wang, Xiaohan; Kachelmeier, Allan; Shi, Xiaorui

2017-03-01

The vestibular blood-labyrinth barrier (BLB) is comprised of perivascular-resident macrophage-like melanocytes (PVM/Ms) and pericytes (PCs), in addition to endothelial cells (ECs) and basement membrane (BM), and bears strong resemblance to the cochlear BLB in the stria vascularis. Over the past few decades, in vitro cell-based models have been widely used in blood-brain barrier (BBB) and blood-retina barrier (BRB) research, and have proved to be powerful tools for studying cell-cell interactions in their respective organs. Study of both the vestibular and strial BLB has been limited by the unavailability of primary culture cells from these barriers. To better understand how barrier component cells interact in the vestibular system to control BLB function, we developed a novel culture medium-based method for obtaining EC, PC, and PVM/M primary cells from tiny explants of the semicircular canal, sacculus, utriculus, and ampullae tissue of young mouse ears at post-natal age 8-12 d. Each phenotype is grown in a specific culture medium which selectively supports the phenotype in a mixed population of vestibular cell types. The unwanted phenotypes do not survive passaging. The protocol does not require additional equipment or special enzyme treatment. The harvesting process takes less than 2 h. Primary cell types are generated within 7-10 d. The primary culture ECs, PCs, and PVM/M shave consistent phenotypes more than 90% pure after two passages (∼ 3 weeks). The highly purified primary cell lines can be used for studying cell-cell interactions, barrier permeability, and angiogenesis. Copyright © 2017 Elsevier B.V. All rights reserved.

PEBS. Long-term performance of engineered barrier systems

Energy Technology Data Exchange (ETDEWEB)

Wieczorek, Klaus; Czaikowski, Oliver; Miehe, Ruediger

2014-12-15

The evolution of the engineered barrier system (EBS) of geological repositories for radioactive waste has been the subject of many national and international research programmes. The emphasis of the research activities was on the elaboration of a detailed understanding of the complex THMC processes, which are expected to evolve in the early post closure period in the near field. From the perspective of radiological long-term safety, an in-depth understanding of these coupled processes is of great significance, because the evolution of the EBS during the early post-closure phase may have a non-negligible impact on the radiological safety functions at the time when the canisters breach. Unexpected process interactions during the resaturation phase could impair the safety-relevant parameters in the EBS (e. g. swelling pressure, hydraulic conductivity, diffusivity).

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)

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)

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....

Barriers to Implementing Evidence-Based Intrapartum Care: A Descriptive Exploratory Qualitative Study.

Science.gov (United States)

Iravani, Mina; Janghorbani, Mohsen; Zarean, Ellahe; Bahrami, Masod

2016-02-01

Evidence based practice is an effective strategy to improve the quality of obstetric care. Identification of barriers to adaptation of evidence-based intrapartum care is necessary and crucial to deliver high quality care to parturient women. The current study aimed to explore barriers to adaptation of evidence-based intrapartum care from the perspective of clinical groups that provide obstetric care in Iran. This descriptive exploratory qualitative research was conducted from 2013 to 2014 in fourteen state medical training centers in Iran. Participants were selected from midwives, specialists, and residents of obstetrics and gynecology, with a purposive sample and snowball method. Data were collected through face-to-face semi-structured in-depth interviews and analyzed according to conventional content analysis. Data analysis identified twenty subcategories and four main categories. Main categories included barriers were related to laboring women, persons providing care, the organization environment and health system. The adoption of evidence based intrapartum care is a complex process. In this regard, identifying potential barriers is the first step to determine and apply effective strategies to encourage the compliance evidence based obstetric care and improves maternity care quality.

Performance Confirmation for the Engineered Barrier System. Report of a Workshop

International Nuclear Information System (INIS)

Bennett, David G.

2004-08-01

As part of preparations for review of future license applications, the Swedish Nuclear Power Inspectorate (SKI) organised a workshop on the engineered barrier system for the KBS-3 concept, focused on Performance Confirmation (PC). The workshop was held during 12 - 14 May, 2004 at Oskarshamn. The main purpose of the workshop was to identify key issues relating to the demonstration of long-term safety using a system of engineered barriers. The workshop began with introductory presentations on Performance Confirmation, on monitoring, and on long-term experiments in underground research laboratories. Working groups were then convened to discuss these topics and identify questions to put to the Swedish Nuclear Fuel and Waste Management Company (SKB) the following day. On the second day, SKB made several presentations, mainly on long-term experiments conducted at the Aespoe underground research laboratory. These presentations were followed by an informal session during which the questions identified by the working groups on the first day were discussed with SKB and its representatives. This report includes the questions identified by the working groups and a summary of the workshop discussions. Extended abstracts for the introductory presentations are included in an appendix. The conclusions and viewpoints presented in this report are those of one or several workshop participants. They do not necessarily coincide with those of SKI

Feasibility study of a single-element transcranial focused ultrasound system for blood-brain barrier opening

Science.gov (United States)

Marquet, Fabrice; Tung, Yao-Sheng; Teichert, Tobias; Ferrera, Vincent P.; Konofagou, Elisa E.

2012-10-01

The blood-brain barrier (BBB) is a specialized vascular system that impedes entry of all large and the vast majority of small molecules including the most potent CNS disease therapeutic agents from entering from the lumen into the brain parenchyma. Microbubble-enhanced, focused ultrasound (ME-FUS) has been previously shown to disrupt noninvasively, selectively, and transiently the BBB in small animals in vivo. The study addresses the focusing properties of single-element transducers at intermediate frequencies (500 kHz) through primate and human skulls, targeting clinically relevant targets extracted from 3D brain atlases such as the hippocampus and the basal ganglia, which are typically affected by early Alzheimer's and Parkinson's disease, respectively. A preliminary in vivo study was performed to study the frequency dependence of BBB opening parameters in mice. Then, feasibility of transcranial ME-FUS BBB opening in non-human primates was demonstrated with subsequent BBB recovery. Sonications were combined with two different types of microbubbles (custom made 4-5 μm and Definity®). 3T MRI was used to confirm the BBB disruption and to assess brain damage.

Induction of selective blood-tumor barrier permeability and macromolecular transport by a biostable kinin B1 receptor agonist in a glioma rat model.

Science.gov (United States)

Côté, Jérôme; Bovenzi, Veronica; Savard, Martin; Dubuc, Céléna; Fortier, Audrey; Neugebauer, Witold; Tremblay, Luc; Müller-Esterl, Werner; Tsanaclis, Ana-Maria; Lepage, Martin; Fortin, David; Gobeil, Fernand

2012-01-01

Treatment of malignant glioma with chemotherapy is limited mostly because of delivery impediment related to the blood-brain tumor barrier (BTB). B1 receptors (B1R), inducible prototypical G-protein coupled receptors (GPCR) can regulate permeability of vessels including possibly that of brain tumors. Here, we determine the extent of BTB permeability induced by the natural and synthetic peptide B1R agonists, LysdesArg(9)BK (LDBK) and SarLys[dPhe(8)]desArg(9)BK (NG29), in syngeneic F98 glioma-implanted Fischer rats. Ten days after tumor inoculation, we detected the presence of B1R on tumor cells and associated vasculature. NG29 infusion increased brain distribution volume and uptake profiles of paramagnetic probes (Magnevist and Gadomer) at tumoral sites (T(1)-weighted imaging). These effects were blocked by B1R antagonist and non-selective cyclooxygenase inhibitors, but not by B2R antagonist and non-selective nitric oxide synthase inhibitors. Consistent with MRI data, systemic co-administration of NG29 improved brain tumor delivery of Carboplatin chemotherapy (ICP-Mass spectrometry). We also detected elevated B1R expression in clinical samples of high-grade glioma. Our results documented a novel GPCR-signaling mechanism for promoting transient BTB disruption, involving activation of B1R and ensuing production of COX metabolites. They also underlined the potential value of synthetic biostable B1R agonists as selective BTB modulators for local delivery of different sized-therapeutics at (peri)tumoral sites.

Progress of the AVNG System - Attribute Verification System with Information Barriers for Mass Isotopics Measurements

International Nuclear Information System (INIS)

Budnikov, D.; Bulatov, M.; Jarikhine, I.; Lebedev, B.; Livke, A.; Modenov, A.; Morkin, A.; Razinkov, S.; Tsaregorodtsev, D.; Vlokh, A.; Yakovleva, S.; Elmont, T.H.; Langner, D.C.; MacArthur, D.W.; Mayo, D.R.; Smith, M.K.; Luke, S.J.

2005-01-01

An attribute verification system (AVNG) with information barriers for mass and isotopics measurements has been designed and its fabrication is nearly completed. The AVNG is being built by scientists at the Russian Federal Nuclear Center-VNIIEF, with support of Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL). Such a system could be used to verify the presence of several unclassified attributes of classified material with no classified information release. The system is comprised of a neutron multiplicity counter and gamma-spectrometry system based on a high purity germanium gamma detector (nominal relative efficiency @ 1332 keV 50%) and digital gamma-ray spectrometer DSPEC PLUS . The neutron multiplicity counter is a three ring counter with 164 3 He tubes. The system was designed to measure prototype containers 491 mm in diameter and 503 mm high. This paper provides a brief history of the project and documents the progress of this effort with drawings and photographs.

Development of a coincidence system for radio-nuclide standardization using surface barrier detectors

International Nuclear Information System (INIS)

Koskinas, M.F.

1988-01-01

A system for the standardization of alpha-gamma or electron-X radionuclide emitters has been developed in the present work. The system consists of one or two surface barrier detectors for alpha or electron detection which are coupled to thin-window NaI (T1) crystals suitable for low energy X or gamma ray detection. The performance of the system has been verified by means of the standardization of 241 Am, 137 Cs and 109 Cd solutions. The activity has been obtained using the extrapolation method applied to the 4Πα-γ and 2Πe c -X coincidence technique. The surface barrier detection efficiency was varied by placing absorbers over the radioactive sources or by changing the source to detector distance. The results were compared to those obtained using conventional absolute systems based on gas-flow and pressurized 4Π proportional counters, or using radioactive solutions standardized in international comparisons spondored by the Bureau International des Poids et Mesures. The expect and measured activities agree within the experimental uncertainties which were: 0.2 % for 241 Am, 0.7% for 137 Cs and 0.6% for 109 Cd. The ratio between the probabilities of (electron capture + internal conversion) and internal conversion for the K-shell of 109 Cd has been determined. The result is: 2.8883 ± 0.016. (author) [pt

[Wavelength Selection in Hemolytic Evaluation Systems with Spectrophotometry Detection].

Science.gov (United States)

Zhang, Hong; Su, Baochang; Ye, Xunda; Luo, Man

2016-04-01

Spectrophotometry is a simple hemolytic evaluation method commonly used in new drugs,biomedical materials and blood products.It is for the quantitative analysis of the characteristic absorption peaks of hemoglobin.Therefore,it is essential to select the correct detection wavelength when the evaluation system has influences on the conformation of hemoglobin.Based on the study of changes in the characteristic peaks over time of the hemolysis supernatant in four systems,namely,cell culture medium,phosphate buffered saline(PBS),physiological saline and banked blood preservation solution,using continuous wavelength scanning,the selections of detection wavelength were proposed as follows.In the cell culture medium system,the wavelength of 415 nm should be selected within 4h;,near 408 nm should be selected within 4~72h.In PBS system,within 4h,541 nm,577nm or 415 nm should be selected;4~72h,541 nm,577nm or near 406 nm should be selected.In physiological saline system,within 4h,414 nm should be selected;4~72h,near 405 nm should be selected;within 12 h,541nm or 577 nm could also be selected.In banked blood preservation solution system,within 72 h,415nm,540 nm or 576 nm should be selected.

Multiuser hybrid switched-selection diversity systems

KAUST Repository

Shaqfeh, Mohammad

2011-09-01

A new multiuser scheduling scheme is proposed and analyzed in this paper. The proposed system combines features of conventional full-feedback selection-based diversity systems and reduced-feedback switch-based diversity systems. The new hybrid system provides flexibility in trading-off the channel information feedback overhead with the prospected multiuser diversity gains. The users are clustered into groups, and the users\\' groups are ordered into a sequence. Per-group feedback thresholds are used and optimized to maximize the system overall achievable rate. The proposed hybrid system applies switched diversity criterion to choose one of the groups, and a selection criterion to decide the user to be scheduled from the chosen group. Numerical results demonstrate that the system capacity increases as the number of users per group increases, but at the cost of more required feedback messages. © 2011 IEEE.

Underutilization of Mental Health Services among College Students: An Examination of System-Related Barriers

Science.gov (United States)

Marsh, Carey N.; Wilcoxon, S. Allen

2015-01-01

Despite the documented benefits of counseling and mental health services on academic performance and degree attainment, only about 10% of psychologically distressed college students ever seek professional help. This investigation examined mental health care system-related barriers that might distinguish help seekers from nonhelp seekers among…

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.

Experimental fusion excitation functions and derived barrier distributions for heavy ion systems involving prolate and oblate target nuclei

International Nuclear Information System (INIS)

Bierman, J.D.; Chan, P.; Liang, J.F.; Kelly, M.P.; Sonzogni, A.A.; Vandenbosch, R.

1996-01-01

Fusion excitation functions spanning the entire barrier region in 1 MeV energy steps for the two systems 40 Ca + 192 Os, 194 Pt are presented. The results of fission fragment angular distribution measurements for fusion-fission of 40 Ca + 197 Au at several projectile energies within the barrier region are also presented. The fusion data is of high enough precision to allow for extraction of the distribution of fusion barriers from the second differential of the product of E and σ. Basic coupled channels calculations which are in quite good agreement with the data are shown and discussed

Advanced Environmental Barrier Coating Development for SiC-SiC Ceramic Matrix Composite Components

Science.gov (United States)

Zhu, Dongming; Harder, Bryan; Hurst, Janet B.; Halbig, Michael Charles; Puleo, Bernadette J.; Costa, Gustavo; Mccue, Terry R.

2017-01-01

This presentation reviews the NASA advanced environmental barrier coating (EBC) system development for SiC-SiC Ceramic Matrix Composite (CMC) combustors particularly under the NASA Environmentally Responsible Aviation, Fundamental Aeronautics and Transformative Aeronautics Concepts Programs. The emphases have been placed on the current design challenges of the 2700-3000F capable environmental barrier coatings for low NOX emission combustors for next generation turbine engines by using advanced plasma spray based processes, and the coating processing and integration with SiC-SiC CMCs and component systems. The developments also have included candidate coating composition system designs, degradation mechanisms, performance evaluation and down-selects; the processing optimizations using TriplexPro Air Plasma Spray Low Pressure Plasma Spray (LPPS), Plasma Spray Physical Vapor Deposition and demonstration of EBC-CMC systems. This presentation also highlights the EBC-CMC system temperature capability and durability improvements under the NASA development programs, as demonstrated in the simulated engine high heat flux, combustion environments, in conjunction with high heat flux, mechanical creep and fatigue loading testing conditions.

Drivers and barriers among householders to managing domestic wastewater treatment systems in the Republic of Ireland; implications for risk prevention behaviour

Science.gov (United States)

Devitt, Catherine; O'Neill, Eoin; Waldron, Richard

2016-04-01

Septic systems that are malfunctioning, improperly sited or designed, present a contamination risk to drinking water sources, and subsequently, to human health. However, the international literature identifies gaps in householder knowledge regarding the function and maintenance requirements of septic systems, and also the potential health and environmental risk implications. Allied with householder fears related to the financial cost of risk management, these factors tend to reduce concern to recognise a malfunctioning system. In the Republic of Ireland, three-quarters of households in rural areas utilise an individual domestic wastewater treatment system (or septic system). Consequently, a significant portion of rural households that rely on groundwater sources via private-well use are at risk. Ireland reports one of the highest crude incidence rates of Verotoxigenic Escherichia coli (VTEC) infection in the European Union, and waterborne transmission related to contact with untreated or poorly treated water from private water sources is a factor in its transmission. Following recent Irish legislative change that places a duty of care on individual householders to ensure a proper system functioning, this exploratory study examines perceptions towards the risk management of septic systems among Irish householders. Using qualitative research methods, four focus groups selected on the basis of geographical variation, and two semi-structured interviews were conducted. While most householders agreed that poorly maintained septic systems represented a threat to the environment and to public health, none reported to having a regular maintenance routine in place. Thematic analysis revealed the drivers and barriers to septic system maintenance, and preferences of householders pertaining to communication on septic systems. The Health Belief Model is employed to help understand results. Results suggest that householder capacity to engage in regular risk management is reduced

Breakup mechanisms for 7Li + 197Au, 204Pb systems at sub-barrier energies

Directory of Open Access Journals (Sweden)

Luong D.H.

2013-12-01

Full Text Available Coincidence measurements of breakup fragments were carried out for the 7Li + 197Au and 204Pb systems at sub-barrier energies. The mechanisms triggering breakup, and time-scales of each process, were identified through the reaction Q-values and the relative energy of the breakup fragments. Binary breakup of 7Li were found to be predominantly triggered by nucleon transfer, with p-pickup leading to 8Be → α + α decay being the preferred breakup mode. From the time-scales of each process, the coincidence yields were separated into prompt and delayed components, allowing the identification of breakup process important in the suppression of complete fusion of 7Li at above-barrier energies.

Time-Sequential Working Wavelength-Selective Filter for Flat Autostereoscopic Displays

Directory of Open Access Journals (Sweden)

René de la Barré

2017-02-01

Full Text Available A time-sequential working, spatially-multiplexed autostereoscopic 3D display design consisting of a fast switchable RGB-color filter array and a fast color display is presented. The newly-introduced 3D display design is usable as a multi-user display, as well as a single-user system. The wavelength-selective filter barrier emits the light from a larger aperture than common autostereoscopic barrier displays with similar barrier pitch and ascent. Measurements on a demonstrator with commercial display components, simulations and computational evaluations have been carried out to describe the proposed wavelength-selective display design in static states and to show the weak spots of display filters in commercial displays. An optical modelling of wavelength-selective barriers has been used for instance to calculate the light ray distribution properties of that arrangement. In the time-sequential implementation, it is important to avoid that quick eye or eyelid movement leads to visible color artifacts. Therefore, color filter cells, switching faster than conventional LC display cells, must distribute directed light from different primaries at the same time, to create a 3D presentation. For that, electric tunable liquid crystal Fabry–Pérot color filters are presented. They switch on-off the colors red, green and blue in the millisecond regime. Their active areas consist of a sub-micrometer-thick nematic layer sandwiched between dielectric mirrors and indium tin oxide (ITO-electrodes. These cells shall switch narrowband light of red, green or blue. A barrier filter array for a high resolution, glasses-free 3D display has to be equipped with several thousand switchable filter elements having different color apertures.

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...

Report to Congress: Coastal Barrier Resources System with recommendations as required by Section 10 of Public Law 97-348, the Coastal Barrier Resources Act of 1982. Volume 1

International Nuclear Information System (INIS)

1988-01-01

The U.S. shoreline bordering the Atlantic Ocean and Gulf of Mexico contains one of the longest and best defined chains of coastal barriers in the world. In recognition of the fact, the Coastal Barrier Resources Act (CBRA) (16 U.S.C. 3501 et seq.) was enacted in October 1982. The Act established the Coastal Barrier Resources System (CBRS) consisting of 186 coastal barrier units along 670 mi of shoreline on the Atlantic and Gulf of Mexico coasts. The philosophy behind the CBRA is that the risk associated with new development in these areas should be borne by those who choose to live and work along the coast, and not by all American taxpayers. By restricting Federal expenditures and financial assistance on specific undeveloped coastal barriers, the Federal Government can minimize the loss of human life, reduce the wasteful expenditure of Federal revenues, and reduce the damage to fish and wildlife and other natural resources that can accompany development of these fragile areas. Section 10 of the CBRA directs the Department of the Interior to study the CBRS and prepare for Congress a report which includes recommendations for changes in the CBRS based on an evaluation of management alternatives that would foster conservation of the natural resources of the CBRS

Richards Barrier LA Reference Design Feature Evaluation

International Nuclear Information System (INIS)

N.E. Kramer

1999-01-01

dusting potential. (6) Evaluate drift conditions and configurations to determine the suitability of Richards Barrier installation methodology. (7) Perform cost assessment of barrier material placement. (8) Evaluate the feature with criteria that will be supplied by the License Application Design Selection (LADS) Team. (9) Comment on the use of depleted uranium as a Richards Barrier material

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.

The socio-technical barriers to Solar Home Systems (SHS) in Papua New Guinea: 'Choosing pigs, prostitutes, and poker chips over panels'

Energy Technology Data Exchange (ETDEWEB)

Sovacool, Benjamin K., E-mail: bsovacool@nus.edu.s [Lee Kuan Yew School of Public Policy, National University of Singapore, 469C Bukit Timah Road, Singapore 259772 (Singapore); D' Agostino, Anthony L.; Jain Bambawale, Malavika [Lee Kuan Yew School of Public Policy, National University of Singapore, 469C Bukit Timah Road, Singapore 259772 (Singapore)

2011-03-15

This study explores the socio-technical barriers to Solar Home Systems (SHS) in Papua New Guinea. The authors collected primary data through semi-structured research interviews conducted over the course of February 2010-April 2010. Respondents included government officials, financiers, planners, commercial distributors and companies, teachers and rural villagers in addition to members of civil society, academics, consultants, and trainers. These interviews were supplemented with site visits to Port Moresby, Goroka, and Madang, and field research in the villages of Akameku, Asaroka, Lufa, Kundiawa, Okifa, Simbu, and Talidig. The study draws from these interviews and visits to discuss four types of barriers. Technical barriers relate to substandard equipment and logistical problems. Economic barriers include high rates of poverty, misconceptions about the role of currency, and lack of financing. Political barriers include poor institutional capacity and a government commitment to fossil-fueled grid electrification. Social barriers encompass unrealistic expectations about what SHS can provide along with jealousy, theft, vandalism, and unfamiliarity with solar technology. - Research highlights: {yields} Solar Home Systems (SHS) are impeded by a collection of different barriers in Papua New Guinea. {yields} Technical barriers relate to substandard equipment and logistical problems. {yields} Economic barriers include high rates of poverty, misconceptions about the role of currency, and lack of financing.{yields} Political barriers include poor institutional capacity and a government commitment to fossil-fueled grid electrification. {yields} Social barriers encompass unrealistic expectations about what SHS can provide along with jealousy, theft, vandalism, and unfamiliarity with solar technology.

EDX and ion beam treatment studies of filamentary in situ MgB2 wires with Ti barrier

International Nuclear Information System (INIS)

Rosova, A.; Kovac, P.; Husek, I.; Kopera, L.

2011-01-01

Highlights: → SiC-doped MgB 2 wires with Ti barrier showed good Jc in magnetic field. → Explanation why the Ti barrier fits to SiC-doped MgB 2 filaments. → Ti barrier getters Si from SiC-doped filaments and improve their properties. → Si accumulated in an inner layer of Ti barrier protects filaments from Cu diffusion. → Ion beam treatment helps to discover microstructure of complicated systems. - Abstract: In situ SiC-doped filamentary MgB 2 wires (with the diameter of 0.860 and 0.375 mm) with Cu stabilization separated by Ti barrier layers supported by outer SS sheath and annealed at 800 deg. C/0.5 h have been studied by combination of EDX analysis and ion beam selective etching. It was found that several Ti-Cu inter-metallic compounds were created by Cu-Ti interdiffusion and thus the barrier protection against Cu penetration into the superconducting filaments is limited. We showed an advantage of Ti use as the barrier material in our wires. Ti getters silicon out from the superconducting filament, what purges superconducting MgB 2 from Si and creates an additional Si-rich layer in inner part of Ti barrier which prevents Cu diffusion more effectively.

Interorganisational Integration: Healthcare Professionals’ Perspectives on Barriers and Facilitators within the Danish Healthcare System

Directory of Open Access Journals (Sweden)

Anne Marie Lyngsø

2016-03-01

Full Text Available Introduction: Despite many initiatives to improve coordination of patient pathways and intersectoral cooperation, Danish health care is still fragmented, lacking intra- and interorganisational integration. This study explores barriers to and facilitators of interorganisational integration as perceived by healthcare professionals caring for patients with chronic obstructive pulmonary disease within the Danish healthcare system. Methods: Seven focus groups were conducted in January through July 2014 with 21 informants from general practice, local healthcare centres and a pulmonary department at a university hospital in the Capital Region of Denmark. Results and discussion: Our results can be grouped into five influencing areas for interorganisational integration: communication/information transfer, committed leadership, patient engagement, the role and competencies of the general practitioner and organisational culture. Proposed solutions to barriers in each area hold the potential to improve care integration as experienced by individuals responsible for supporting and facilitating it. Barriers and facilitators to integrating care relate to clinical, professional, functional and normative integration. Especially, clinical, functional and normative integration seems fundamental to developing integrated care in practice from the perspective of healthcare professionals.

Quantifying system safety: A comparison of the SBOAT & Safety Barrier Manager tools

OpenAIRE

Hansen, Zaza Nadja Lee; Duijm, Nijs Jan; Markert, Frank; Herbert, Luke Thomas

2015-01-01

This paper presents two software tools for analyzing safety risks, SBOAT (Stochastic BPMN Optimisation and Analysis Tool) and SBM (SafetyBarrierManagerr). SBOAT employs principles from stochastic model checking to allow for the quantitative verification of workflows. SBM supports the creation of valid safety-barrier diagrams and allows the quantitative analysis of the probability of all possible end states of the barrier diagram, i.e. the outcomes if one or several of the barriers fail to per...

Barriers to the success of an electronic pharmacovigilance reporting system in Kenya: an evaluation three years post implementation.

Science.gov (United States)

Agoro, Oscar O; Kibira, Sarah W; Freeman, Jenny V; Fraser, Hamish S F

2018-06-01

Electronic pharmacovigilance reporting systems are being implemented in many developing countries in an effort to improve reporting rates. This study sought to establish the factors that acted as barriers to the success of an electronic pharmacovigilance reporting system in Kenya 3 years after its implementation. Factors that could act as barriers to using electronic reporting systems were identified in a review of literature and then used to develop a survey questionnaire that was administered to pharmacists working in government hospitals in 6 counties in Kenya. The survey was completed by 103 out of the 115 targeted pharmacists (89.5%) and included free-text comments. The key factors identified as barriers were: unavailable, unreliable, or expensive Internet access; challenges associated with a hybrid system of paper and electronic reporting tools; and system usability issues. Coordination challenges at the national pharmacovigilance center and changes in the structure of health management in the country also had an impact on the success of the electronic reporting system. Different personal, organizational, infrastructural, and reporting system factors affect the success of electronic reporting systems in different ways, depending on the context. Context-specific formative evaluations are useful in establishing the performance of electronic reporting systems to identify problems and ensure that they achieve the desired objectives. While several factors hindered the optimal use of the electronic pharmacovigilance reporting system in Kenya, all were considered modifiable. Effort should be directed toward tackling the identified issues in order to facilitate use and improve pharmacovigilance reporting rates.

Selection Method for COTS Systems

DEFF Research Database (Denmark)

Hedman, Jonas; Andersson, Bo

2014-01-01

feature behind the method is that improved understanding of organizational ‘ends’ or goals should govern the selection of a COTS system. This can also be expressed as a match or fit between ‘ends’ (e.g. improved organizational effectiveness) and ‘means’ (e.g. implementing COTS systems). This way...

Health system and societal barriers for gestational diabetes mellitus (GDM) services - lessons from World Diabetes Foundation supported GDM projects

DEFF Research Database (Denmark)

Nielsen, Karoline Kragelund; de Courten, Maximilian; Kapur, Anil

2012-01-01

for the offspring. A better understanding of the barriers hindering detection and treatment of GDM is needed. Based on experiences from World Diabetes Foundation (WDF) supported GDM projects this paper seeks to investigate societal and health system barriers to such efforts. Methods Questionnaires were filled out...... by 10 WDF supported GDM project partners implementing projects in eight different LMIC. In addition, interviews were conducted with the project partners. The interviews were analysed using content analysis. Results Barriers to improving maternal health related to GDM nominated by project implementers...

Transcytosis in the blood–cerebrospinal fluid barrier of the mouse brain with an engineered receptor/ligand system

Directory of Open Access Journals (Sweden)

Héctor R Méndez-Gómez

Full Text Available Crossing the blood–brain and the blood–cerebrospinal fluid barriers (BCSFB is one of the fundamental challenges in the development of new therapeutic molecules for brain disorders because these barriers prevent entry of most drugs from the blood into the brain. However, some large molecules, like the protein transferrin, cross these barriers using a specific receptor that transports them into the brain. Based on this mechanism, we engineered a receptor/ligand system to overcome the brain barriers by combining the human transferrin receptor with the cohesin domain from Clostridium thermocellum, and we tested the hybrid receptor in the choroid plexus of the mouse brain with a dockerin ligand. By expressing our receptor in choroidal ependymocytes, which are part of the BCSFB, we found that our systemically administrated ligand was able to bind to the receptor and accumulate in ependymocytes, where some of the ligand was transported from the blood side to the brain side.

Expert System Model for Educational Personnel Selection

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Héctor A. Tabares-Ospina

2013-06-01

Full Text Available The staff selection is a difficult task due to the subjectivity that the evaluation means. This process can be complemented using a system to support decision. This paper presents the implementation of an expert system to systematize the selection process of professors. The management of software development is divided into 4 parts: requirements, design, implementation and commissioning. The proposed system models a specific knowledge through relationships between variables evidence and objective.

Energy barrier of bcc-fcc phase transition via the Bain path in Yukawa system

Science.gov (United States)

Kiyokawa, Shuji

2018-05-01

In the Yukawa system with the dimensionless screening parameter κ>1.5 , when bcc-fcc transition occurs via Bain path, we show that spontaneous transitions do not occur even if the system temperature reaches the transition point of bcc-fcc because it is necessary to increase once the free energy in the process of transition from bcc to fcc through Bain deformation. Here, we refer the temporary increment of the free energy during Bain deformation as Bain barrier. Since there are the Bain barriers at the transitions between bcc and fcc phases, these phases may coexist as metastable state in the wide region (not a coexistence line) of κ and the coupling constant Γ. We study the excess energy of the system and the free energy difference between bcc and fcc phases by the Monte Carlo method, where the simulation box is divided into a large number of elements with small volume and a particle in the box is restricted be placed in one of these elements. By this method, we can tabulate the values of the interparticle potential and can calculate the internal energy fast and precisely.

Selection of nuclear power information database management system

International Nuclear Information System (INIS)

Zhang Shuxin; Wu Jianlei

1996-01-01

In the condition of the present database technology, in order to build the Chinese nuclear power information database (NPIDB) in the nuclear industry system efficiently at a high starting point, an important task is to select a proper database management system (DBMS), which is the hinge of the matter to build the database successfully. Therefore, this article explains how to build a practical information database about nuclear power, the functions of different database management systems, the reason of selecting relation database management system (RDBMS), the principles of selecting RDBMS, the recommendation of ORACLE management system as the software to build database and so on

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

“Zebrafishing” for Novel Genes Relevant to the Glomerular Filtration Barrier

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Nils Hanke

2013-01-01

Full Text Available Data for genes relevant to glomerular filtration barrier function or proteinuria is continually increasing in an era of microarrays, genome-wide association studies, and quantitative trait locus analysis. Researchers are limited by published literature searches to select the most relevant genes to investigate. High-throughput cell cultures and other in vitro systems ultimately need to demonstrate proof in an in vivo model. Generating mammalian models for the genes of interest is costly and time intensive, and yields only a small number of test subjects. These models also have many pitfalls such as possible embryonic mortality and failure to generate phenotypes or generate nonkidney specific phenotypes. Here we describe an in vivo zebrafish model as a simple vertebrate screening system to identify genes relevant to glomerular filtration barrier function. Using our technology, we are able to screen entirely novel genes in 4–6 weeks in hundreds of live test subjects at a fraction of the cost of a mammalian model. Our system produces consistent and reliable evidence for gene relevance in glomerular kidney disease; the results then provide merit for further analysis in mammalian models.

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)

Understanding critical barriers to implementing a clinical information system in a nursing home through the lens of a socio-technical perspective.

Science.gov (United States)

Or, Calvin; Dohan, Michael; Tan, Joseph

2014-09-01

This paper addresses key barriers to implementing a clinical information system (CIS) in a Hong Kong nursing home setting, from a healthcare specific socio-technical perspective. Data was collected through field observations (n = 12) and semi-structured individual interviews (n = 18) of CIS stakeholders in a Hong Kong nursing home, and analyzed using the immersion/crystallization approach. Complex interactions relevant to our case were contextualized and interpreted within the perspective of the Sittig-Singh Healthcare Socio-Technical Framework (HSTF). Three broad clusters of implementation barriers from the eight HSTF dimensions were identified: (a) Infrastructure-based barriers, which relate to conflict between government regulations and system functional needs of users; lack of financial support; inconsistency between workflow, work policy, and procedures; and inadequacy of hardware-software infrastructural and technical support; (b) Process-based barriers, which relate to mismatch between the technology, existing work practice and workflow, and communication; low system speed, accessibility, and stability; deficient computer literacy; more experience in health care profession; clinical content inadequacy and unavailability; as well as poor system usefulness and user interface design; and (c) Outcome-based barriers, which relate to the lack of measurement and monitoring of system effectiveness. Two additional dimensions underlining the importance of the ability of a CIS to change are proposed to extend the Sittig-Singh HSTF. First, advocacy would promote the articulation and influence of changes in the system and subsequent outcomes by CIS stakeholders, and second, adaptability would ensure the ability of the system to adjust to emerging needs. The broad set of discovered implementation shortcomings expands prior research on why CIS can fail in nursing home settings. Moreover, our investigation offers a knowledge base and recommendations that can serve

Connectivity and systemic resilience of the Great Barrier Reef.

Directory of Open Access Journals (Sweden)

Karlo Hock

2017-11-01

Full Text Available Australia's iconic Great Barrier Reef (GBR continues to suffer from repeated impacts of cyclones, coral bleaching, and outbreaks of the coral-eating crown-of-thorns starfish (COTS, losing much of its coral cover in the process. This raises the question of the ecosystem's systemic resilience and its ability to rebound after large-scale population loss. Here, we reveal that around 100 reefs of the GBR, or around 3%, have the ideal properties to facilitate recovery of disturbed areas, thereby imparting a level of systemic resilience and aiding its continued recovery. These reefs (1 are highly connected by ocean currents to the wider reef network, (2 have a relatively low risk of exposure to disturbances so that they are likely to provide replenishment when other reefs are depleted, and (3 have an ability to promote recovery of desirable species but are unlikely to either experience or spread COTS outbreaks. The great replenishment potential of these 'robust source reefs', which may supply 47% of the ecosystem in a single dispersal event, emerges from the interaction between oceanographic conditions and geographic location, a process that is likely to be repeated in other reef systems. Such natural resilience of reef systems will become increasingly important as the frequency of disturbances accelerates under climate change.

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.

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)

Development of a alpha spectrometer system with the surface barrier detector

International Nuclear Information System (INIS)

Alencar, Marcus Alexandre Vallini de

1994-04-01

The aim of this work is the development of an α spectrometer of low cost and home made technology. The spectrometer is mounted in a double NIM module and includes a surface barrier detector and dedicate electronic system. Six barrier surface detectors were made, three of which with η type silicon wafer 3350 Ω.cm, 270mm 2 and three other with ρ type silicon wafer 5850 Ω.cm and 220mm 2 . The rectifier and the ohmic contacts were prepared at high vacuum (10 -2 to 10 -3 Pa) evaporation with 40μg/cm 2 of Au and Al respectively for the η type detectors, and with Al and Au respectively for the ρ type detectors. The electronic system is composed by a low noise charge sensitive preamplifier with the operational amplifier LF-356 mounted with 1OOMΩ feedback resistor and a 0.5 pF capacitor. The linear amplifier is also based in the LF-356 and the LM-310 operational amplifier. The bipolar output is formatted through a (CR) 2- (RC) 4 shaping network and the unipolar output is obtained through a CR-(RC) 4 shaping system which is sufficient to realize a almost true Gaussian shaping pulse with a time constant of 3.0μs. This format was chosen because we can expect a low counting rate and the gaussian pulse can improve the signal/noise ratio. The first CR differentiation has also a active pole-zero cancellation network.The resolution of detectors for 241 Am α particles at room temperature (24 degree) vary 21 to 44 keV FWHM. The electronic noise of the noise of the system is 7.5 keV FWHM at OpF input capacitance. The overall resolution of the spectrometer was found to be 62 keV FWHM at room temperature. The simplicity of the electronic system, the low cost of the construction and the overall resolution show that this alpha spectrometer can be readily used in measurements where high resolution is not a premium. (author)

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.

The Development of Environmental Barrier Coating Systems for SiC-SiC Ceramic Matrix Composites: Environment Effects on the Creep and Fatigue Resistance

Science.gov (United States)

Zhu, Dongming; Ghosn, Louis J.

2014-01-01

Topics covered include: Environmental barrier coating system development: needs, challenges and limitations; Advanced environmental barrier coating systems (EBCs) for CMC airfoils and combustors; NASA EBC systems and material system evolutions, Current turbine and combustor EBC coating emphases, Advanced development, processing, testing and modeling, EBC and EBC bond coats: recent advances; Design tool and life prediction of coated CMC components; Advanced CMC-EBC rig demonstrations; Summary and future directions.

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

Polymers for subterranean containment barriers for underground storage tanks (USTs)

International Nuclear Information System (INIS)

Heiser, J.H.; Colombo, P.; Clinton, J.

1992-12-01

The US Department of Energy (DOE) set up the Underground Storage Tank Integrated Demonstration Program (USTID) to demonstrate technologies for the retrieval and treatment of tank waste, and closure of underground storage tanks (USTs). There are more than 250 underground storage tanks throughout the DOE complex. These tanks contain a wide variety of wastes including high level, low level, transuranic, mixed and hazardous wastes. Many of the tanks have performed beyond the designed lifetime resulting in leakage and contamination of the local geologic media and groundwater. To mitigate this problem it has been proposed that an interim subterranean containment barrier be placed around the tanks. This would minimize or prevent future contamination of soil and groundwater in the event that further tank leakages occur before or during remediation. Use of interim subterranean barriers can also provide sufficient time to evaluate and select appropriate remediation alternatives. The DOE Hanford site was chosen as the demonstration site for containment barrier technologies. A panel of experts for the USTID was convened in February, 1992, to identify technologies for placement of subterranean barriers. The selection was based on the ability of candidate grouts to withstand high radiation doses, high temperatures and aggressive tank waste leachates. The group identified and ranked nine grouting technologies that have potential to place vertical barriers and five for horizontal barriers around the tank. The panel also endorsed placement technologies that require minimal excavation of soil surrounding the tanks

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.

Selective Attention in Multi-Chip Address-Event Systems

Directory of Open Access Journals (Sweden)

Giacomo Indiveri

2009-06-01

Full Text Available Selective attention is the strategy used by biological systems to cope with the inherent limits in their available computational resources, in order to efficiently process sensory information. The same strategy can be used in artificial systems that have to process vast amounts of sensory data with limited resources. In this paper we present a neuromorphic VLSI device, the “Selective Attention Chip” (SAC, which can be used to implement these models in multi-chip address-event systems. We also describe a real-time sensory-motor system, which integrates the SAC with a dynamic vision sensor and a robotic actuator. We present experimental results from each component in the system, and demonstrate how the complete system implements a real-time stimulus-driven selective attention model.

Selective attention in multi-chip address-event systems.

Science.gov (United States)

Bartolozzi, Chiara; Indiveri, Giacomo

2009-01-01

Selective attention is the strategy used by biological systems to cope with the inherent limits in their available computational resources, in order to efficiently process sensory information. The same strategy can be used in artificial systems that have to process vast amounts of sensory data with limited resources. In this paper we present a neuromorphic VLSI device, the "Selective Attention Chip" (SAC), which can be used to implement these models in multi-chip address-event systems. We also describe a real-time sensory-motor system, which integrates the SAC with a dynamic vision sensor and a robotic actuator. We present experimental results from each component in the system, and demonstrate how the complete system implements a real-time stimulus-driven selective attention model.

Performance of engineered barrier materials in near surface disposal facilities for radioactive waste. Results of a co-ordinated research project

International Nuclear Information System (INIS)

2001-11-01

The primary objectives of the CRP were to: promote the sharing of experiences of the Member States in their application of engineered barrier materials for near surface disposal facilities; help enhance their use of engineered barriers by improving techniques and methods for selecting, planning and testing performance of various types of barrier materials for near surface disposal facilities. The objective of this publication is to provide and overview of technical issues related to the engineered barrier systems and a summary of the major findings of each individual research project that was carried out within the framework of the CRP. This publication deals with a general overview of engineered barriers in near surface disposal facilities, key technical information obtained within the CRP and overall conclusions and recommendations for future research and development activities. Appendices presenting individual research accomplishments are also provided. Each of the 13 appendices was indexed separately

Long term performance of the Waterloo denitrification barrier

International Nuclear Information System (INIS)

Robertson, W.D.; Cherry, J.A.

1997-01-01

Beginning in 1991 a series of laboratory tests and small scale field trials were initiated to test the performance of an innovative permeable reactive barrier for treatment of nitrate from septic systems. The barrier promotes denitrification by providing an energy source in the form of solid organic carbon mixed into the porous media material. Advantages of the system for nitrate treatment are that the reaction is passive and in situ and it is possible to incorporate sufficient carbon mass in conveniently sized barriers to potentially provide treatment for long periods (decades) without the necessity for maintenance. However, longevity can only be demonstrated by careful long term monitoring of field installations. This paper documents four years of operating history at three small scale field trials; two where the denitrification barrier is installed as a horizontal layer positioned in the unsaturated zone below conventional septic system infiltration beds and one where the barrier is installed as a vertical wall intercepting a septic system plume at a downgradient location. The barriers have successfully attenuated 50-100% of NO - 3 -N levels of up to 170 mg/L and treatment has remained consistent over the four year period in each case, thus considerable longevity is indicated. Other field trials have demonstrated this technology to be equally effective in treating nitrogen contamination from other sources such as landfill leachate and farm field runoff

Nuclear reactions of the system 6 Li on 58 Ni near the Coulomb barrier

International Nuclear Information System (INIS)

Lizcano, D.; Aguilera, E.F.; Garcia M, H.; Martinez Q, E.

2004-01-01

Protons, alpha particles and deuterons coming from the reactions 6 Li + 58 Ni are detected to three different energy around the Coulomb barrier. The possible effects of the weakly bound character of the projectile are studied and the results are compared with previous data for the system 6 Li + 59 Co. (Author)

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

Integrating observational and modelling systems for the management of the Great Barrier Reef

Science.gov (United States)

Baird, M. E.; Jones, E. M.; Margvelashvili, N.; Mongin, M.; Rizwi, F.; Robson, B.; Schroeder, T.; Skerratt, J.; Steven, A. D.; Wild-Allen, K.

2016-02-01

Observational and modelling systems provide two sources of knowledge that must be combined to provide a more complete view than either observations or models alone can provide. Here we describe the eReefs coupled hydrodynamic, sediment and biogeochemical model that has been developed for the Great Barrier Reef; and the multiple observations that are used to constrain the model. Two contrasting examples of model - observational integration are highlighted. First we explore the carbon chemistry of the waters above the reef, for which observations are accurate, but expensive and therefore sparse, while model behaviour is highly skilful. For carbon chemistry, observations are used to constrain model parameterisation and quantify model error, with the model output itself providing the most useable knowledge for management purposes. In contrast, ocean colour provides inaccurate, but cheap and spatially and temporally extensive observations. Thus observations are best combined with the model in a data assimilating framework, where a custom-designed optical model has been developed for the purposes of incorporating ocean colour observations. The future management of Great Barrier Reef water quality will be based on an integration of observing and modelling systems, providing the most robust information available.

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.

Understanding barriers and facilitators to the use of Clinical Information Systems for intensive care units and Anesthesia Record Keeping: A rapid ethnography.

Science.gov (United States)

Saleem, Jason J; Plew, William R; Speir, Ross C; Herout, Jennifer; Wilck, Nancy R; Ryan, Dale Marie; Cullen, Theresa A; Scott, Jean M; Beene, Murielle S; Phillips, Toni

2015-07-01

This study evaluated the current use of commercial-off-the-shelf Clinical Information Systems (CIS) for intensive care units (ICUs) and Anesthesia Record Keeping (ARK) for operating rooms and post-anesthesia care recovery settings at three Veterans Affairs Medical Centers (VAMCs). Clinicians and administrative staff use these applications at bedside workstations, in operating rooms, at nursing stations, in physician's rooms, and in other various settings. The intention of a CIS or an ARK system is to facilitate creation of electronic records of data, assessments, and procedures from multiple medical devices. The US Department of Veterans Affairs (VA) Office of the Chief of Nursing Informatics sought to understand usage barriers and facilitators to optimize these systems in the future. Therefore, a human factors study was carried out to observe the CIS and ARK systems in use at three VAMCs in order to identify best practices and suggested improvements to currently implemented CIS and ARK systems. We conducted a rapid ethnographic study of clinical end-users interacting with the CIS and ARK systems in the critical care and anesthesia care areas in each of three geographically distributed VAMCs. Two observers recorded interactions and/or interview responses from 88 CIS and ARK end-users. We coded and sorted into logical categories field notes from 69 shadowed participants. The team transcribed and combined data from key informant interviews with 19 additional participants with the observation data. We then integrated findings across observations into meaningful patterns and abstracted the data into themes, which translated directly to barriers to effective adoption and optimization of the CIS and ARK systems. Effective optimization of the CIS and ARK systems was impeded by: (1) integration issues with other software systems; (2) poor usability; (3) software challenges; (4) hardware challenges; (5) training concerns; (6) unclear roles and lack of coordination among

Selection Process of ERP Systems

OpenAIRE

Molnár, Bálint; Szabó, Gyula; Benczúr, András

2013-01-01

Background: The application and introduction of ERP systems have become a central issue for management and operation of enterprises. The competition on market enforces the improvement and optimization of business processes of enterprises to increase their efficiency, effectiveness, and to manage better the resources outside the company. The primary task of ERP systems is to achieve the before-mentioned objectives. Objective: The selection of a particular ERP system has a decisive effect on th...

Induction of selective blood-tumor barrier permeability and macromolecular transport by a biostable kinin B1 receptor agonist in a glioma rat model.

Directory of Open Access Journals (Sweden)

Jérôme Côté

Full Text Available Treatment of malignant glioma with chemotherapy is limited mostly because of delivery impediment related to the blood-brain tumor barrier (BTB. B1 receptors (B1R, inducible prototypical G-protein coupled receptors (GPCR can regulate permeability of vessels including possibly that of brain tumors. Here, we determine the extent of BTB permeability induced by the natural and synthetic peptide B1R agonists, LysdesArg(9BK (LDBK and SarLys[dPhe(8]desArg(9BK (NG29, in syngeneic F98 glioma-implanted Fischer rats. Ten days after tumor inoculation, we detected the presence of B1R on tumor cells and associated vasculature. NG29 infusion increased brain distribution volume and uptake profiles of paramagnetic probes (Magnevist and Gadomer at tumoral sites (T(1-weighted imaging. These effects were blocked by B1R antagonist and non-selective cyclooxygenase inhibitors, but not by B2R antagonist and non-selective nitric oxide synthase inhibitors. Consistent with MRI data, systemic co-administration of NG29 improved brain tumor delivery of Carboplatin chemotherapy (ICP-Mass spectrometry. We also detected elevated B1R expression in clinical samples of high-grade glioma. Our results documented a novel GPCR-signaling mechanism for promoting transient BTB disruption, involving activation of B1R and ensuing production of COX metabolites. They also underlined the potential value of synthetic biostable B1R agonists as selective BTB modulators for local delivery of different sized-therapeutics at (peritumoral sites.

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

Vegetation barrier and tillage effects on runoff and sediment in an alley crop system on a Luvisol in Burkina Faso

NARCIS (Netherlands)

Spaan, W.P.; Sikking, A.F.S.; Hoogmoed, W.B.

2005-01-01

The effects of vegetation barriers and tillage on runoff and soil loss were evaluated in an alley crop system at a research station in central Burkina Faso. On a 2% slope of a sandy loam various local species (grasses, woody species and a succulent) were planted as conservation barriers in order to

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.

Near barrier fusion, breakup and scattering for the 9Be + 144Sm system

International Nuclear Information System (INIS)

Paes, B.; Lubian, J.; Gomes, P.R.S.; Padron, I.; Canto, L.F.

2009-01-01

Full text: The investigation of the break-up process of weakly bound nuclei and its influence on the fusion cross section and elastic scattering has been investigated in the last years by different approaches. One of these approaches is the comparison of data of complete fusion (CF) cross sections with predictions from CC calculations which do not include the break-up channel. Different phenomena leading to opposite effects on the fusion cross section may be identified: static effects arising from the longer tail of the nuclear potential and the large size of the weakly bound nuclei, leading to a smaller Coulomb barrier, and dynamical effects, either like the strong coupling between the elastic and continuum states, that takes flux that otherwise would go to fusion or like the coupling of soft resonance states. Very recently a method has been developed by us to disentangle these effects. Another approach to perform this study is the investigation of the presence or absence of the threshold anomaly or the break-up threshold anomaly in the elastic scattering at near barrier energies. The attractive or repulsive characters of the polarization potentials associated with the different reaction processes, may lead to enhancement or suppression of the fusion cross section. In this contribution we analyze, by different approaches, a large set of data for the 9 Be + 144 Sm system, including CF and incomplete fusion, elastic and inelastic scattering. We use a reliable double folding potential in CC calculations which either do not take into account the break-up channel or consider resonances of the 9 Be projectile; we also perform simultaneous fits of elastic and CF cross sections; we derive the break-up cross sections and investigate the energy dependence of the real and imaginary optical potentials corresponding to the fusion and direct processes, separately; and we derive the break-up polarization potential for this system. Then, we show the agreement between these

Interaction between blood-brain barrier and glymphatic system in solute clearance.

Science.gov (United States)

Verheggen, I C M; Van Boxtel, M P J; Verhey, F R J; Jansen, J F A; Backes, W H

2018-03-30

Neurovascular pathology concurs with protein accumulation, as the brain vasculature is important for waste clearance. Interstitial solutes, such as amyloid-β, were previously thought to be primarily cleared from the brain by blood-brain barrier transport. Recently, the glymphatic system was discovered, in which cerebrospinal fluid is exchanged with interstitial fluid, facilitated by the aquaporin-4 water channels on the astroglial endfeet. Glymphatic flow can clear solutes from the interstitial space. Blood-brain barrier transport and glymphatic clearance likely serve complementary roles with partially overlapping mechanisms providing a well-conditioned neuronal environment. Disruption of these mechanisms can lead to protein accumulation and may initiate neurodegenerative disorders, for instance amyloid-β accumulation and Alzheimer's disease. Although both mechanisms seem to have a similar purpose, their interaction has not been clearly discussed previously. This review focusses on this interaction in healthy and pathological conditions. Future health initiatives improving waste clearance might delay or even prevent onset of neurodegenerative disorders. Defining glymphatic flow kinetics using imaging may become an alternative way to identify those at risk of Alzheimer's disease. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

ARTIFICIAL NEURAL NETWORKS BASED GEARS MATERIAL SELECTION HYBRID INTELLIGENT SYSTEM

Institute of Scientific and Technical Information of China (English)

X.C. Li; W.X. Zhu; G. Chen; D.S. Mei; J. Zhang; K.M. Chen

2003-01-01

An artificial neural networks(ANNs) based gear material selection hybrid intelligent system is established by analyzing the individual advantages and weakness of expert system (ES) and ANNs and the applications in material select of them. The system mainly consists of tow parts: ES and ANNs. By being trained with much data samples,the back propagation (BP) ANN gets the knowledge of gear materials selection, and is able to inference according to user input. The system realizes the complementing of ANNs and ES. Using this system, engineers without materials selection experience can conveniently deal with gear materials selection.

Financing Solar Energy Systems with Energy Savings Performance Contracts in the Federal Sector: Results of a Survey on Barriers

Energy Technology Data Exchange (ETDEWEB)

Gee, R. C.; LaPorta, C.

1999-08-17

This report summarizes the findings of an investigation into financing solar energy systems for the Federal sector. The objectives of the investigation were (1) to identify the barriers that impede companies from using Energy Savings Performance Contracts (ESPCs) to develop solar energy projects for Federal facilities, and (2) to clarify the impacts of Federal contracting requirements on energy service companies' use of ESPCs. Twenty-four representatives of energy service companies agreed to be interviewed. Their responses indicate that these are the primary barriers to greater use of ESPCs: the relatively long payback periods for investments in solar technologies; the length of the ESPC process; the cost of certain contractual requirements regarding wages and financing; and a lack of knowledge about the actual cost and reliability of solar systems. The report proposes a number of actions the government could take to remove these barriers, including (1) streamlining and shortening the ESPC process and (2) doing more to inform both government agencies and energy service companies about the costs and benefits of solar systems.

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...

Selection on plant male function genes identifies candidates for reproductive isolation of yellow monkeyflowers.

Directory of Open Access Journals (Sweden)

Jan E Aagaard

Full Text Available Understanding the genetic basis of reproductive isolation promises insight into speciation and the origins of biological diversity. While progress has been made in identifying genes underlying barriers to reproduction that function after fertilization (post-zygotic isolation, we know much less about earlier acting pre-zygotic barriers. Of particular interest are barriers involved in mating and fertilization that can evolve extremely rapidly under sexual selection, suggesting they may play a prominent role in the initial stages of reproductive isolation. A significant challenge to the field of speciation genetics is developing new approaches for identification of candidate genes underlying these barriers, particularly among non-traditional model systems. We employ powerful proteomic and genomic strategies to study the genetic basis of conspecific pollen precedence, an important component of pre-zygotic reproductive isolation among yellow monkeyflowers (Mimulus spp. resulting from male pollen competition. We use isotopic labeling in combination with shotgun proteomics to identify more than 2,000 male function (pollen tube proteins within maternal reproductive structures (styles of M. guttatus flowers where pollen competition occurs. We then sequence array-captured pollen tube exomes from a large outcrossing population of M. guttatus, and identify those genes with evidence of selective sweeps or balancing selection consistent with their role in pollen competition. We also test for evidence of positive selection on these genes more broadly across yellow monkeyflowers, because a signal of adaptive divergence is a common feature of genes causing reproductive isolation. Together the molecular evolution studies identify 159 pollen tube proteins that are candidate genes for conspecific pollen precedence. Our work demonstrates how powerful proteomic and genomic tools can be readily adapted to non-traditional model systems, allowing for genome-wide screens

Economic evaluation of closure cap barrier materials study

Energy Technology Data Exchange (ETDEWEB)

Serrato, M.G.; Bhutani, J.S.; Mead, S.M.

1993-09-01

Volume II of the Economic Evaluation of the Closure Cap Barrier Materials, Revision I contains detailed cost estimates for closure cap barrier materials. The cost estimates incorporate the life cycle costs for a generic hazardous waste seepage basin closure cap under the RCRA Post Closure Period of thirty years. The economic evaluation assessed six barrier material categories. Each of these categories consists of several composite cover system configurations, which were used to develop individual cost estimates. The information contained in this report is not intended to be used as a cost estimating manual. This information provides the decision makers with the ability to screen barrier materials, cover system configurations, and identify cost-effective materials for further consideration.

Economic evaluation of closure cap barrier materials study

International Nuclear Information System (INIS)

Serrato, M.G.; Bhutani, J.S.; Mead, S.M.

1993-09-01

Volume II of the Economic Evaluation of the Closure Cap Barrier Materials, Revision I contains detailed cost estimates for closure cap barrier materials. The cost estimates incorporate the life cycle costs for a generic hazardous waste seepage basin closure cap under the RCRA Post Closure Period of thirty years. The economic evaluation assessed six barrier material categories. Each of these categories consists of several composite cover system configurations, which were used to develop individual cost estimates. The information contained in this report is not intended to be used as a cost estimating manual. This information provides the decision makers with the ability to screen barrier materials, cover system configurations, and identify cost-effective materials for further consideration

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....

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

ERP systems selection in multinational enterprises: a practical guide

OpenAIRE

Moutaz Haddara

2018-01-01

The Enterprise Resource Planning (ERP) system selection is an early phase in the ERP adoption process. When organizations evaluate an ERP, they commonly develop their own selection criteria that usually involve various system and vendor related factors. While the selection process is critical, however, there is an apparent research gap in literature. The ERP selection effort also focuses on the system’s fit with the organizational requirements and needs. Thus, the selection phase is critical,...

Feasibility of permeation grouting for constructing subsurface barriers

International Nuclear Information System (INIS)

Dwyer, B.P.

1994-03-01

The technical feasibility of emplacing a barrier beneath a waste site using directionally drilled boreholes and permeation grouting was investigated. The benefits of this emplacement system are: (1) Directionally drilled boreholes provide access beneath a waste site without disturbing the waste; (2) interim containment of contaminants allows time for the development of remediation options; (3) in the interim, the volume of waste remains fixed; (4) barriers may enhance the effectiveness of in situ remediation actions; and (5) barrier systems may provide permanent waste containment

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.

Barriers to Leisure-Time Physical Activities in Individuals with Spinal Cord Injury.

Science.gov (United States)

Hwang, Eric J; Groves, Mary D; Sanchez, Jacqueline N; Hudson, Cassandra E; Jao, Rachel G; Kroll, Meghan E

2016-07-01

This study investigated the personal, environmental, and activity barriers to leisure-time physical activities (LTPAs) among individuals with spinal cord injury (SCI). A survey instrument was administered to 85 participants with SCI. Personal barriers to LTPAs included issues involving motivation, pain, scheduling, and financial resources. Environmental barriers marked the issues regarding availability and accessibility to specialized programs, activities, and professional services. Activity barriers included limitations in equipment, training, and personal skills required by the selected activities. Significant negative correlations were found between these barriers and the levels of physical activity and satisfaction with physical activity. While working with clients with SCI, occupational therapists should identify those LTPA barriers and possible solutions in order to establish individualized action plans for enhancing participation in LTPAs.

Magnetic Materials: Novel Monitors of Long-Term Evolution of Engineered Barrier Systems

Directory of Open Access Journals (Sweden)

Simon L. Harley

2016-12-01

Full Text Available Most safety cases for the deep geological disposal of radioactive waste are reliant on the swelling of bentonite in the engineered barrier system as it saturates with groundwater. Assurance of safety therefore requires effective monitoring of bentonite saturation. The time- and fluid-dependent corrosion of synthetic magnets embedded in bentonite is demonstrated here to provide a novel and passive means of monitoring saturation. Experiments have been conducted at 70 °C in which neo magnets, AlNiCo magnets, and ferrite magnets have been reacted with saline (NaCl, KCl, CaCl2 solutions and alkaline fluids (NaOH, KOH, Ca(OH2 solutions; pH = 12 in the presence of bentonite. Nd-Fe-B magnets undergo extensive corrosion that results in a dramatic change from ferromagnetic to superparamagnetic behaviour concomitant with bentonite saturation. AlNiCo magnets in saline solutions show corrosion but only limited decreases in their magnetic intensities, and ferrite magnets are essentially unreactive on the experimental timescales, retaining their initial magnetic properties. For all magnets the impact of their corrosion on bentonite swelling is negligible; alteration of bentonite is essentially governed by the applied fluid composition. In principle, synthetic magnet arrays can, with further development, be designed and embedded in bentonite to monitor its fluid saturation without compromising the integrity of the engineered barrier system itself.

Effects of sea-level rise on barrier island groundwater system dynamics: ecohydrological implications

Science.gov (United States)

Masterson, John P.; Fienen, Michael N.; Thieler, E. Robert; Gesch, Dean B.; Gutierrez, Benjamin T.; Plant, Nathaniel G.

2014-01-01

We used a numerical model to investigate how a barrier island groundwater system responds to increases of up to 60 cm in sea level. We found that a sea-level rise of 20 cm leads to substantial changes in the depth of the water table and the extent and depth of saltwater intrusion, which are key determinants in the establishment, distribution and succession of vegetation assemblages and habitat suitability in barrier islands ecosystems. In our simulations, increases in water-table height in areas with a shallow depth to water (or thin vadose zone) resulted in extensive groundwater inundation of land surface and a thinning of the underlying freshwater lens. We demonstrated the interdependence of the groundwater response to island morphology by evaluating changes at three sites. This interdependence can have a profound effect on ecosystem composition in these fragile coastal landscapes under long-term changing climatic conditions.

Socio-cultural barriers to the development of a sustainable energy system - the case of hydrogen

Energy Technology Data Exchange (ETDEWEB)

Kjerulf Petersen, L.; Holst Andersen, A.

2009-02-15

Any transition to a more sustainable energy system, radically reducing greenhouse gas emissions, is bound to run in to a host of different barriers - technological and economic, but also socio-cultural. This will also be the case for any large-scale application of hydrogen as energy carrier, especially if the system is going to be based on renewable energy sources. The aim of these research notes is to review and discuss major socio-cultural barriers to new forms of energy supply in general and to hydrogen specifically. Reaching sufficient reductions in greenhouse gas emissions may require more than large-scale dissemination of renewable energy sources. Also reductions or moderations in energy demand may be necessary. Hence, a central point in the research note is to consider not only socio-cultural obstacles for changing technologies in energy production, distribution and consumption but also obstacles for changing the scale of energy consumption, i.e. moderating the growth in how much energy is consumed or even reducing consumption volumes. (au)

Selection strategy for the most Suitable CEC method for clay barrier characterisation

International Nuclear Information System (INIS)

Dohrmann, R.; Kaufhold, S.

2010-01-01

Document available in extended abstract form only. The cation exchange capacity (CEC) is one of the most relevant properties of clay barriers. CEC results often are used for characterization of the clay host rock or for sensitive detection of degradation of the barrier material, e.g. bentonite buffer. Numerous methods exist for the determination of the CEC and exchangeable cations. However, a lot of methods suffer from systematic errors. These errors are caused by interactions (that differ from cation exchange) of the exchange solutions used with minerals in the barrier material: i) Dissolution of soluble minerals such as calcite, gypsum, or dolomite which causes inflated exchangeable calcium (magnesium) values. Other reactions of carbonates or gypsum not only affect exchangeable cations but also the CEC (index cation) values in a way that ii) witherite (barium carbonate) is formed and dissolved later (barium chloride method) which causes inflated CEC values or iii) rests of gypsum are present during reexchange with magnesium chloride (barium chloride method) which then leads to drastic CEC underestimation by formation of barium sulphate (here simultaneously barium ions are desorbed from exchange positions and sulphate enters the solution due to gypsum dissolution). When the ammonium acetate method is used for CEC determination of calcareous clays/bentonites another mechanism for a systematic CEC decrease occurs: iv) ammonium acetate is first used to saturate the clay components in a regular way (cation exchange), but during washing for removal of excess salt, ammonium is desorbed again from exchange positions by calcium which is liberated (dissolved) from remaining calcite of calcareous clays studied. Other errors may be v) the degradation of cationic complexes (silver thiourea, if pH > 8) or vi) substances which are added to adjust the pH of the exchange solutions such as triethanolamine in barium chloride exchange solution which may be protonated and adsorbed in

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

Hanford prototype-barrier status report: FY 1995

International Nuclear Information System (INIS)

Gee, G.W.; Ward, A.L.; Gilmore, B.G.; Ligotke, M.W.; Link, S.O.

1995-11-01

Surface barriers (or covers) have been proposed for use at the Hanford Site as a means to isolate certain waste sites that, for reasons of cost or worker safety or both, may not be exhumed. Surface barriers are intende to isolated the wastes from the accessible environment and to provide long-term protection to future populations that might use the Hanford Site. Currently, no ''proven'' long-term barrier system is available. For this reason, the Hanford Site Permanent Isolation Surface-Barrier Development Program (BDP) was organized to develop the technology needed to provide long-term surface barrier capability for the Hanford Site for the US Department of Energy (DOE). Designs have been proposed to meet the most stringent needs for long-term waste disposal. The objective of the current barrier design is to use natural materials to develop a protective barrier system that isolates wastes for at least 1000 years by limiting water, plant, animal, and human intrusion; and minimizing erosion. The design criteria for water drainage has been set at 0.5 mm/yr. While other design criteria are more qualitative, it is clear that waste isolation for an extended time is the prime objective of the design. Constructibility and performance. are issues that can be tested and dealt with by evaluating prototype designs prior to extensive construction and deployment of covers for waste sites at Hanford

Evolution of mid-Atlantic coastal and back-barrier estuary environments in response to a hurricane: Implications for barrier-estuary connectivity

Science.gov (United States)

Miselis, Jennifer L.; Andrews, Brian D.; Nicholson, Robert S.; Defne, Zafer; Ganju, Neil K.; Navoy, Anthony S.

2016-01-01

Assessments of coupled barrier island-estuary storm response are rare. Hurricane Sandy made landfall during an investigation in Barnegat Bay-Little Egg Harbor estuary that included water quality monitoring, geomorphologic characterization, and numerical modeling; this provided an opportunity to characterize the storm response of the barrier island-estuary system. Barrier island morphologic response was characterized by significant changes in shoreline position, dune elevation, and beach volume; morphologic changes within the estuary were less dramatic with a net gain of only 200,000 m3 of sediment. When observed, estuarine deposition was adjacent to the back-barrier shoreline or collocated with maximum estuary depths. Estuarine sedimentologic changes correlated well with bed shear stresses derived from numerically simulated storm conditions, suggesting that change is linked to winnowing from elevated storm-related wave-current interactions rather than deposition. Rapid storm-related changes in estuarine water level, turbidity, and salinity were coincident with minima in island and estuarine widths, which may have influenced the location of two barrier island breaches. Barrier-estuary connectivity, or the transport of sediment from barrier island to estuary, was influenced by barrier island land use and width. Coupled assessments like this one provide critical information about storm-related coastal and estuarine sediment transport that may not be evident from investigations that consider only one component of the coastal system.

Sensor Selection method for IoT systems – focusing on embedded system requirements

Directory of Open Access Journals (Sweden)

Hirayama Masayuki

2016-01-01

Full Text Available Recently, various types of sensors have been developed. Using these sensors, IoT systems have become hot topics in embedded system domain. However, sensor selections for embedded systems are not well discussed up to now. This paper focuses on embedded system’s features and architecture, and proposes a sensor selection method which is composed seven steps. In addition, we applied the proposed method to a simple example – a sensor selection for computer scored answer sheet reader unit. From this case study, an idea to use FTA in sensor selection is also discussed.

Implementation of Computer Assisted Test Selection System in Local Governments

Directory of Open Access Journals (Sweden)

Abdul Azis Basri

2016-05-01

Full Text Available As an evaluative way of selection of civil servant system in all government areas, Computer Assisted Test selection system was started to apply in 2013. In phase of implementation for first time in all areas in 2014, this system selection had trouble in several areas, such as registration procedure and passing grade. The main objective of this essay was to describe implementation of new selection system for civil servants in the local governments and to seek level of effectiveness of this selection system. This essay used combination of study literature and field survey which data collection was made by interviews, observations, and documentations from various sources, and to analyze the collected data, this essay used reduction, display data and verification for made the conclusion. The result of this essay showed, despite there a few parts that be problem of this system such as in the registration phase but almost all phases of implementation of CAT selection system in local government areas can be said was working clearly likes in preparation, implementation and result processing phase. And also this system was fulfilled two of three criterias of effectiveness for selection system, they were accuracy and trusty. Therefore, this selection system can be said as an effective way to select new civil servant. As suggestion, local governments have to make prime preparation in all phases of test and make a good feedback as evaluation mechanism and together with central government to seek, fix and improve infrastructures as supporting tool and competency of local residents.

Identifying Facilitators and Barriers for Patient Safety in a Medicine Label Design System Using Patient Simulation and Interviews

DEFF Research Database (Denmark)

Dieckmann, Peter; Clemmensen, Marianne Hald; Sørensen, Trine Kart

2016-01-01

Objectives Medicine label design plays an important role in improving patient safety. This study aimed at identifying facilitators and barriers in a medicine label system to prevent medication errors in clinical use by health care professionals. Methods The study design is qualitative and explora......Objectives Medicine label design plays an important role in improving patient safety. This study aimed at identifying facilitators and barriers in a medicine label system to prevent medication errors in clinical use by health care professionals. Methods The study design is qualitative...... of the system and some inconsistencies (different meaning of colors) posed challenges, when considered with the actual application context, in which there is little time to get familiar with the design features. Conclusions For optimizing medicine labels and obtaining the full benefit of label design features...

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)

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)

Fusion of light ion systems at energies near and below the Coulomb barrier

International Nuclear Information System (INIS)

Arnould, M.; Howard, W.M.; Cusson, R.Y.

1978-01-01

Experimental fusion cross sections for light ion systems at energies below the Coulomb barrier become available in greater and greater number, and provide a stringent test of the macroscopic and microscopic physics involved in models of heavy-ion reactions. Measurements and predictions of the fusion cross sections for 12 C + 12 C, 12 C + 16 O and 16 O + 16 O are also of major importance in astrophysics. (orig.) [de

New concepts for drift pumping a thermal barrier with rf

International Nuclear Information System (INIS)

Barter, J.D.; Baldwin, D.; Chen, Y.; Poulsen, P.

1985-01-01

Pump neutral beams, which are directed into the loss cone of the TMX-U plugs, are normally used to pump ions from the thermal barriers. Because these neutral beams introduce cold gas that reduces pumping efficiency, and require a straight line entrance and exit from the plug, alternate methods are being investigated to provide barrier pumping. To maintain the thermal barrier, either of two classes of particles can be pumped. First, the collisionally trapped ions can be pumped directly. In this case, the most promising selection criterion is the azimuthal drift frequency. Second, the excess sloshing-ion density can be removed, allowing the use of increased sloshing-beam density to pump the trapped ions. The selection mechanism in this case is the Doppler-shifted ion-cyclotron resonance of the high-energy sloshing-ions (3 keV less than or equal to U/sub parallel/ less than or equal to 10 keV)

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)

Asphalt emulsion radon barrier systems for uranium mill tailings: an overview of the technology

International Nuclear Information System (INIS)

Baker, E.G.; Hartley, J.N.; Freeman, H.D.; Gates, T.E.; Nelson, D.A.; Dunning, R.L.

1984-03-01

Pacific Northwest Laboratory (PNL), under contract to the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action Project (UMTRAP) office, has developed an asphalt emulsion cover system to reduce the release of radon from uranium mill tailings. The system has been field tested at Grand Junction, Colorado. Results from laboratory and field tests indicate that this system is effective in reducing radon release to near-background levels ( -2 s -1 ) and has the properties required for long-term effectiveness and stability. Engineering specifications have been developed, and analysis indicates that asphalt emulsion covers are cost-competitive with other cover systems. This report summarizes the technology for asphalt emulsion radon barrier systems. 59 references, 45 figures, 36 tables

Barriers and post-closure monitoring (AL121125)

International Nuclear Information System (INIS)

Bostick, K.V.; Janecky, D.

1995-01-01

This project focuses on the rapid implementation of near-surface barriers, biotreatment, and post-closure monitoring technology. It uses water-permeable and biologic barriers that chemically capture and/or degrade contaminants without significantly altering the natural water flow regime. Barrier approaches are being tested for two different applications. The first is the use of barriers for confinement of chemical contaminants for in-trench treatments with leach systems or an in-place bioreactor. The second is an enhancement of the current practice of emplacing grout or clay slurry walls into direct horizontal surface and subsurface water flows around a contaminated area by integrating permeable reactive barriers and petroleum reservoir gel/foam/polymer technology

46 CFR 108.404 - Selection of fire detection system.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Selection of fire detection system. 108.404 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems § 108.404 Selection of fire detection system. (a) If a... space. (b) The fire detection system must be designed to minimize false alarms. ...

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.

Optimistic Selection Rule Better Than Majority Voting System

Science.gov (United States)

Sugiyama, Takuya; Obata, Takuya; Hoki, Kunihito; Ito, Takeshi

A recently proposed ensemble approach to game-tree search has attracted a great deal of attention. The ensemble system consists of M computer players, where each player uses a different series of pseudo-random numbers. A combination of multiple players under the majority voting system would improve the performance of a Shogi-playing computer. We present a new strategy of move selection based on the search values of a number of players. The move decision is made by selecting one player from all M players. Each move is selected by referring to the evaluation value of the tree search of each player. The performance and mechanism of the strategy are examined. We show that the optimistic selection rule, which selects the player that yields the highest evaluation value, outperforms the majority voting system. By grouping 16 or more computer players straightforwardly, the winning rates of the strongest Shogi programs increase from 50 to 60% or even higher.

Monitoring active species in an atmospheric pressure dielectric-barrier discharge: Observation of the Herman-infrared system

Czech Academy of Sciences Publication Activity Database

Annušová, A.; Čermák, P.; Rakovský, Jozef; Martišovitš, V.; Veis, P.

2017-01-01

Roč. 57, č. 2 (2017), s. 67-75 ISSN 0863-1042 Institutional support: RVO:61388955 Keywords : dielectric-barrier discharge * Herman-infrared system * nitrogen Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.440, year: 2016

Protection of blood retinal barrier and systemic vasculature by insulin-like growth factor binding protein-3.

Directory of Open Access Journals (Sweden)

Yagna P R Jarajapu

Full Text Available Previously, we showed that insulin growth factor (IGF-1 binding protein-3 (IGFBP-3, independent of IGF-1, reduces pathological angiogenesis in a mouse model of the oxygen-induced retinopathy (OIR. The current study evaluates novel endothelium-dependent functions of IGFBP-3 including blood retinal barrier (BRB integrity and vasorelaxation. To evaluate vascular barrier function, either plasmid expressing IGFBP-3 under the regulation of an endothelial-specific promoter or a control plasmid was injected into the vitreous humor of mouse pups (P1 and compared to the non-injected eyes of the same pups undergoing standard OIR protocol. Prior to sacrifice, the mice were given an injection of horseradish peroxidase (HRP. IGFBP-3 plasmid-injected eyes displayed near-normal vessel morphology and enhanced vascular barrier function. Further, in vitro IGFBP-3 protects retinal endothelial cells from VEGF-induced loss of junctional integrity by antagonizing the dissociation of the junctional complexes. To assess the vasodilatory effects of IGFBP-3, rat posterior cerebral arteries were examined in vitro. Intraluminal IGFBP-3 decreased both pressure- and serotonin-induced constrictions by stimulating nitric oxide (NO release that were blocked by L-NAME or scavenger receptor-B1 neutralizing antibody (SRB1-Ab. Both wild-type and IGF-1-nonbinding mutant IGFBP-3 (IGFBP-3NB stimulated eNOS activity/NO release to a similar extent in human microvascular endothelial cells (HMVECs. NO release was neither associated with an increase in intracellular calcium nor decreased by Ca(2+/calmodulin-dependent protein kinase II (CamKII blockade; however, dephosphorylation of eNOS-Thr(495 was observed. Phosphatidylinositol 3-kinase (PI3K activity and Akt-Ser(473 phosphorylation were both increased by IGFBP-3 and selectively blocked by the SRB1-Ab or PI3K blocker LY294002. In conclusion, IGFBP-3 mediates protective effects on BRB integrity and mediates robust NO release to stimulate

Morphological response of a barrier island system on a catastrophic event

DEFF Research Database (Denmark)

Fruergaard, Mikkel; Kroon, Aart

2016-01-01

storms are capable of moving large amounts of sediments over relatively short time-periods and can create barrier shoals, whereas moderate storms mostly rework the shoal or barrier and create more local erosion and/or landward migration. Catastrophic storms substantially influence long-term and large...

ERP systems selection in multinational enterprises: a practical guide

Directory of Open Access Journals (Sweden)

Moutaz Haddara

2018-01-01

Full Text Available The Enterprise Resource Planning (ERP system selection is an early phase in the ERP adoption process. When organizations evaluate an ERP, they commonly develop their own selection criteria that usually involve various system and vendor related factors. While the selection process is critical, however, there is an apparent research gap in literature. The ERP selection effort also focuses on the system’s fit with the organizational requirements and needs. Thus, the selection phase is critical, because if an organization chooses an unfit ERP, the whole project could be predestined to fail. This research provides an overview of an ERP selection process at an overseas branch office of a multinational company. The process employed a simple multi-attribute rating technique (SMART for evaluation. In addition, this research presents how cross-border data protection laws between the parent company and its branch have influenced the selection process. As the ERP system has been implemented successfully, the method and the selection factors have been proven adequate for the selection process.

THE ROLE OF MULTIDRUG RESISTANCE ASSOCIATED PROTEIN (MRP) IN THE BLOOD-BRAIN BARRIER AND OPIOID ANALGESIA

Science.gov (United States)

Su, Wendy; Pasternak, Gavril W.

2013-01-01

The blood brain barrier protects the brain from circulating compounds and drugs. The ATP-binding cassette (ABC) transporter P-glycoprotein (Pgp) is involved with the barrier, both preventing the influx of agent from the blood into the brain and facilitating the efflux of compounds from the brain into the blood, raising the possibility of a similar role for other transporters. Multidrug resistance associated protein (MRP), a 190 kDa protein similar to Pgp is also ABC transport that has been implicated in the blood brain barrier. The current study explores its role in opioid action. Immunohistochemically, it is localized in the choroid plexus in ratsand can be selectively downregulated by antisense treatment at both the level of mRNA, as shown by RT-PCR, and protein, as demonstrated immunohistochemically. Behaviorally, downregulation of MRP significantly enhances the analgesic potency of systemic morphine in MRP knockout mice and in antisense-treated rats by lowering the blood brain barrier. Following intracerebroventricular administration, a number of compounds, including some opioids, are rapidly secreted from the brain into the blood where they contribute to the overall analgesic effects by activating peripheral systems. MRP plays a role in this efflux. Downregulating MRP expression leads to a corresponding decrease in the transport and a diminished analgesic response from opioids administered intracerebroventricularly. Thus, the transporter protein MRP plays a role in maintaining the blood-brain barrier and modulates the activity of opioids. PMID:23508590

Energy management action plan: Developing a strategy for overcoming institutional barriers to municipal energy conservation

Energy Technology Data Exchange (ETDEWEB)

1992-12-31

Energy offices working to improve efficiency of local government facilities face not only technical tasks, but institutional barriers, such as budget structures that do not reward efficiency, a low awareness of energy issues, and purchasing procedures based only on minimizing initial cost. The bureau, in working to remove such barriers in San Francisco, has identified 37 institutional barriers in areas such as operations & maintenance, purchasing, and facility design; these barriers were then reorganized into three groupings-- policy & attitudes, budget & incentives, and awareness & information-- and mapped. This map shows that the barriers mutually reinforce each other, and that a holistic approach is required for permanent change. The city`s recreation & parks department was used as a model department, and information about facility energy use was compiled into a departmental energy review. Staff interviews showed how barriers affect conservation. The bureau then generated ideas for projects to remove specific barriers and rated them according to potential impact and the resources required to implement them. Four of the six projects selected focused on maintenance staff: a cost- sharing lighting retrofit program, a boiler efficiency program, a departmental energy tracking system, and a budgetary incentive program for conservation. The other two projects are city-wide: promotion of a new term contract supplying energy-efficient light materials, and publication/distribution of ENERGY NEWS newsletter. A general methodology, the EMAP Strategy Guide, has been created to assist other energy offices in developing EMAPs.

BENCHMARKING THE INTERACTIONS AMONG BARRIERS IN DAIRY SUPPLY CHAIN: AN ISM APPROACH

Directory of Open Access Journals (Sweden)

Rahul S Mor

2018-06-01

Full Text Available The purpose of this paper is to explore the key barriers in dairy supply chain and to analyze their interactions in the context of Indian dairy industry. A total of eight barriers have been identified through literature review and the opinions of an expert team consisting of managerial and technical experts from dairy industry and academics. A questionnaire has been developed for identified barriers and responses were collected from select dairy industries located at northern India. Interpretive structure modeling (ISM is used to analyze the interactions among barriers and to propose a structural model. Further, the importance of barriers is determined based on their driving and dependence power using MICMAC analysis. The ISM-based model allocates to 'traceability, unbalanced production line, over-processing' as key barriers, 'wastages and high production downtime' comes next. MICMAC analysis depicts one autonomous barrier, one dependent barrier and six linkage barriers. The ISM-based model and MICMAC analysis will support the decision makers in dairy industry for planning their supply chain activities in an efficient way by managing the identified barriers.

Determining Barriers and Facilitators Associated With Willingness to Use a Personal Health Information Management System to Support Worksite Wellness Programs.

Science.gov (United States)

Neyens, David M; Childers, Ashley Kay

2017-07-01

To determine the barriers and facilitators associated with willingness to use personal health information management (PHIM) systems to support an existing worksite wellness program (WWP). The study design involved a Web-based survey. The study setting was a regional hospital. Hospital employees comprised the study subjects. Willingness, barriers, and facilitators associated with PHIM were measured. Bivariate logit models were used to model two binary dependent variables. One model predicted the likelihood of believing PHIM systems would positively affect overall health and willingness to use. Another predicted the likelihood of worrying about online security and not believing PHIM systems would benefit health goals. Based on 333 responses, believing PHIM systems would positively affect health was highly associated with willingness to use PHIM systems (p < .01). Those comfortable online were 7.22 times more willing to use PHIM systems. Participants in exercise-based components of WWPs were 3.03 times more likely to be willing to use PHIM systems. Those who worried about online security were 5.03 times more likely to believe PHIM systems would not help obtain health goals. Comfort with personal health information online and exercise-based WWP experience was associated with willingness to use PHIM systems. However, nutrition-based WWPs did not have similar effects. Implementation barriers relate to technology anxiety and trust in security, as well as experience with specific WWP activities. Identifying differences between WWP components and addressing technology concerns before implementation of PHIM systems into WWPs may facilitate improved adoption and usage.