T Tank Farm Interim Surface Barrier Demonstration--Vadose Zone Monitoring Plan

International Nuclear Information System (INIS)

Zhang, Z. F.; Keller, Jason M.; Strickland, Christopher E.

2007-01-01

The Hanford Site has 149 underground single-shell tanks that store hazardous radioactive waste. Many of these tanks and their associated infrastructure (e.g., pipelines, diversion boxes) have leaked. Some of the leaked waste has entered the groundwater. The largest known leak occurred from the T-106 Tank in 1973. Many of the contaminants from that leak still reside within the vadose zone beneath the T Tank Farm. CH2M Hill Hanford Group, Inc. seeks to minimize movement of this residual contaminant plume by placing an interim barrier on the surface. Such a barrier is expected to prevent infiltrating water from reaching the plume and moving it further. A plan has been prepared to monitor and determine the effectiveness of the interim surface barrier. Soil water content and water pressure will be monitored using off-the-shelf equipment that can be installed by the hydraulic hammer technique. In fiscal year 2006, two instrument nests were installed. Each instrument nest contains a neutron probe access tube, a capacitance probe, four heat-dissipation units, and a drain gauge to measure soil water flux. A meteorological station has been installed outside of the fence. In fiscal year 2007, two additional instrument nests are planned to be installed beneath the proposed barrier.

Moisture barrier properties of single-layer graphene deposited on Cu films for Cu metallization

Science.gov (United States)

Gomasang, Ploybussara; Abe, Takumi; Kawahara, Kenji; Wasai, Yoko; Nabatova-Gabain, Nataliya; Thanh Cuong, Nguyen; Ago, Hiroki; Okada, Susumu; Ueno, Kazuyoshi

2018-04-01

The moisture barrier properties of large-grain single-layer graphene (SLG) deposited on a Cu(111)/sapphire substrate are demonstrated by comparing with the bare Cu(111) surface under an accelerated degradation test (ADT) at 85 °C and 85% relative humidity (RH) for various durations. The change in surface color and the formation of Cu oxide are investigated by optical microscopy (OM) and X-ray photoelectron spectroscopy (XPS), respectively. First-principle simulation is performed to understand the mechanisms underlying the barrier properties of SLG against O diffusion. The correlation between Cu oxide thickness and SLG quality are also analyzed by spectroscopic ellipsometry (SE) measured on a non-uniform SLG film. SLG with large grains shows high performance in preventing the Cu oxidation due to moisture during ADT.

Overcoming Barriers: Women in Superintendency

Science.gov (United States)

Miller, Claire M.

2009-01-01

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

Effects of single and repeated exposure to biocidal active substances on the barrier function of the skin in vitro.

Science.gov (United States)

Buist, Harrie E; van de Sandt, Johannes J M; van Burgsteden, Johan A; de Heer, Cees

2005-10-01

The dermal route of exposure is important in worker exposure to biocidal products. Many biocidal active substances which are used on a daily basis may decrease the barrier function of the skin to a larger extent than current risk assessment practice addresses, due to possible skin effects of repeated exposure. The influence of repeated and single exposure to representative biocidal active substances on the skin barrier was investigated in vitro. The biocidal active substances selected were alkyldimethylbenzylammonium chloride (ADBAC), boric acid, deltamethrin, dimethyldidecylammonium chloride (DDAC), formaldehyde, permethrin, piperonyl butoxide, sodium bromide, and tebuconazole. Of these nine compounds, only the quaternary ammonium chlorides ADBAC and DDAC had a clear and consistent influence on skin permeability of the marker compounds tritiated water and [(14)C]propoxur. For these compounds, repeated exposure increased skin permeability more than single exposure. At high concentrations the difference between single and repeated exposure was quantitatively significant: repeated exposure to 300 mg/L ADBAC increased skin permeability two to threefold in comparison to single exposure. Therefore, single and repeated exposure to specific biocidal products may significantly increase skin permeability, especially when used undiluted.

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

Invertebrate population genetics across Earth's largest habitat: The deep-sea floor.

Science.gov (United States)

Taylor, M L; Roterman, C N

2017-10-01

Despite the deep sea being the largest habitat on Earth, there are just 77 population genetic studies of invertebrates (115 species) inhabiting non-chemosynthetic ecosystems on the deep-sea floor (below 200 m depth). We review and synthesize the results of these papers. Studies reveal levels of genetic diversity comparable to shallow-water species. Generally, populations at similar depths were well connected over 100s-1,000s km, but studies that sampled across depth ranges reveal population structure at much smaller scales (100s-1,000s m) consistent with isolation by adaptation across environmental gradients, or the existence of physical barriers to connectivity with depth. Few studies were ocean-wide (under 4%), and 48% were Atlantic-focused. There is strong emphasis on megafauna and commercial species with research into meiofauna, "ecosystem engineers" and other ecologically important species lacking. Only nine papers account for ~50% of the planet's surface (depths below 3,500 m). Just two species were studied below 5,000 m, a quarter of Earth's seafloor. Most studies used single-locus mitochondrial genes revealing a common pattern of non-neutrality, consistent with demographic instability or selective sweeps; similar to deep-sea hydrothermal vent fauna. The absence of a clear difference between vent and non-vent could signify that demographic instability is common in the deep sea, or that selective sweeps render single-locus mitochondrial studies demographically uninformative. The number of population genetics studies to date is miniscule in relation to the size of the deep sea. The paucity of studies constrains meta-analyses where broad inferences about deep-sea ecology could be made. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Barriers to and drivers for energy efficiency in the Swedish foundry industry

International Nuclear Information System (INIS)

Rohdin, Patrik; Thollander, Patrik; Solding, Petter

2007-01-01

Despite the need for increased industrial energy efficiency, studies indicate that cost-efficient energy conservation measures are not always implemented, explained by the existence of barriers to energy efficiency. This paper investigates the existence of different barriers to and driving forces for the implementation of energy efficiency measures in the energy intensive Swedish foundry industry. The overall results from a questionnaire show that limited access to capital constitutes by far the largest barrier to energy efficiency according to the respondents. A comparison between group-owned and privately owned foundries shows that, except for limited access to capital, they face different high-ranked barriers. While barriers within group owned companies are more related to organizational problems, barriers within private foundries are more related to information problems. This study also found that energy consultants or other actors working with energy issues in foundries are of major importance in overcoming the largest barriers, as the foundries consider them trustworthy. They may thus help the foundries overcome organizational problems such as lack of sub-metering and lack of budget funds by quantifying potential energy efficiency investments. The two, by far, most important drivers were found to be people with real ambition and long-term energy strategies

Bubble nucleation in simple and molecular liquids via the largest spherical cavity method

International Nuclear Information System (INIS)

Gonzalez, Miguel A.; Abascal, José L. F.; Valeriani, Chantal; Bresme, Fernando

2015-01-01

In this work, we propose a methodology to compute bubble nucleation free energy barriers using trajectories generated via molecular dynamics simulations. We follow the bubble nucleation process by means of a local order parameter, defined by the volume of the largest spherical cavity (LSC) formed in the nucleating trajectories. This order parameter simplifies considerably the monitoring of the nucleation events, as compared with the previous approaches which require ad hoc criteria to classify the atoms and molecules as liquid or vapor. The combination of the LSC and the mean first passage time technique can then be used to obtain the free energy curves. Upon computation of the cavity distribution function the nucleation rate and free-energy barrier can then be computed. We test our method against recent computations of bubble nucleation in simple liquids and water at negative pressures. We obtain free-energy barriers in good agreement with the previous works. The LSC method provides a versatile and computationally efficient route to estimate the volume of critical bubbles the nucleation rate and to compute bubble nucleation free-energies in both simple and molecular liquids

Numerical simulation of torus breakdown to chaos in an atmospheric-pressure dielectric barrier discharge

International Nuclear Information System (INIS)

Zhang, J.; Wang, Y. H.; Wang, D. Z.

2013-01-01

Understanding the routes to chaos occurring in atmospheric-pressure dielectric barrier discharge systems by changing controlling parameters is very important to predict and control the dynamical behaviors. In this paper, a route of a quasiperiodic torus to chaos via the strange nonchaotic attractor is observed in an atmospheric-pressure dielectric barrier discharge driven by triangle-wave voltage. By increasing the driving frequency, the discharge system first bifurcates to a quasiperiodic torus from a stable single periodic state, and then torus and phase-locking periodic state appear and disappear alternately. In the meantime, the torus becomes increasingly wrinkling and stretching, and gradually approaches a fractal structure with the nonpositive largest Lyapunov exponent, i.e., a strange nonchaotic attractor. After that, the discharge system enters into chaotic state. If the driving frequency is further increased, another well known route of period-doubling bifurcation to chaos is also observed

Numerical simulation of torus breakdown to chaos in an atmospheric-pressure dielectric barrier discharge

Energy Technology Data Exchange (ETDEWEB)

Zhang, J.; Wang, Y. H.; Wang, D. Z. [Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2013-08-15

Understanding the routes to chaos occurring in atmospheric-pressure dielectric barrier discharge systems by changing controlling parameters is very important to predict and control the dynamical behaviors. In this paper, a route of a quasiperiodic torus to chaos via the strange nonchaotic attractor is observed in an atmospheric-pressure dielectric barrier discharge driven by triangle-wave voltage. By increasing the driving frequency, the discharge system first bifurcates to a quasiperiodic torus from a stable single periodic state, and then torus and phase-locking periodic state appear and disappear alternately. In the meantime, the torus becomes increasingly wrinkling and stretching, and gradually approaches a fractal structure with the nonpositive largest Lyapunov exponent, i.e., a strange nonchaotic attractor. After that, the discharge system enters into chaotic state. If the driving frequency is further increased, another well known route of period-doubling bifurcation to chaos is also observed.

Barriers to fusion

International Nuclear Information System (INIS)

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

1999-01-01

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

Self-organization of single filaments and diffusive plasmas during a single pulse in dielectric-barrier discharges

International Nuclear Information System (INIS)

Babaeva, Natalia Yu; Kushner, Mark J

2014-01-01

Self-organization of filaments in dielectric-barrier discharges (DBDs) probably has many origins. However, the dominant cause is proposed to be the accumulation of charge on the surfaces of the bounding dielectrics that reinforces successive discharge pulses to occur at the same locations. A secondary cause is the electrostatic repulsion of individual plasma filaments. Self-organization typically develops over many discharge pulses. In this paper, we discuss the results of a computational investigation of plasma filaments in overvoltage DBDs that, under select conditions, display self-organized patterns (SOPs) of plasma density during a single discharge pulse. (Overvoltage refers to the rapid application of a voltage in excess of the quasi-dc breakdown voltage.) The origin of the SOPs is a synergistic relationship between the speed of the surface-ionization waves that propagate along each dielectric and the rate at which avalanche occurs across the gap. For our test conditions, SOPs were not observed at lower voltages and gradually formed at higher voltages. The same conditions that result in SOPs, i.e. the application of an overvoltage, also produce more diffuse discharges. A transition from a single narrow filament to a more diffuse structure was observed as overvoltage was approached. The sensitivity of SOPs to the orientation and permittivity of the bounding dielectrics is discussed. (paper)

Functions and requirements for subsurface barriers used in support of single-shell tank waste retrieval

International Nuclear Information System (INIS)

Lowe, S.S.

1993-01-01

The mission of the Tank Waste Remediation System (TWRS) Program is to store, treat, and immobilize highly radioactive Hanford waste in an environmentally sound, safe, and cost-effective manner. The scope of the TWRS Program includes project and program activities for receiving, storing, maintaining, treating, and disposing onsite, or packaging for offsite disposal, all Hanford tank waste. Hanford tank waste includes the contents of 149 single-shell tanks (SSTs) and 28 double-shell tanks (DSTs), plus any new waste added to these facilities, and all encapsulated cesium and strontium stored onsite and returned from offsite users. A key element of the TWRS Program is retrieval of the waste in the SSTs. The waste stored in these underground tanks must be removed in order to minimize environmental, safety, and health risks associated with continuing waste storage. Subsurface barriers are being considered as a means to mitigate the effects of tank leaks including those occurring during SST waste retrieval. The functions to be performed by subsurface barriers based on their role in retrieving waste from the SSTs are described, and the requirements which constrain their application are identified. These functions and requirements together define the functional baseline for subsurface barriers

Numerical study of the influence of applied voltage on the current balance factor of single layer organic light-emitting diodes

International Nuclear Information System (INIS)

Lu, Fei-ping; Liu, Xiao-bin; Xing, Yong-zhong

2014-01-01

Current balance factor (CBF) value, the ratio of the recombination current density and the total current density of a device, has an important function in fluorescence-based organic light-emitting diodes (OLEDs), as well as in the performance of the organic electrophosphorescent devices. This paper investigates the influence of the applied voltage of a device on the CBF value of single layer OLED based on the numerical model of a bipolar single layer OLED with organic layer trap free and without doping. Results show that the largest CBF value can be achieved when the electron injection barrier (ϕ n ) is equal to the hole injection barrier (ϕ p ) in the lower voltage region at any instance. The largest CBF in the higher voltage region can be achieved in the case of ϕ n  > ϕ p under the condition of electron mobility (μ 0n ) > hole mobility (μ 0p ), whereas the result for the case of μ 0n   0p , is opposite. The largest CBF when μ 0n  = μ 0p can be achieved in the case of ϕ n  = ϕ p in the entire region of the applied voltage. In addition, the CBF value of the device increases with increasing applied voltage. The results obtained in this paper can present an in-depth understanding of the OLED working mechanism and help in the future fabrication of high efficiency OLEDs

Development of CdTe/Cd1-xMgxTe double barrier, single quantum well heterostructure for resonant tunneling

International Nuclear Information System (INIS)

Reuscher, G.; Keim, M.; Fischer, F.; Waag, A.; Landwehr, G.

1995-01-01

We report the first observation of resonant tunneling through a CdTe/Cd 1-x Mg x Te double barrier, single quantum well heterostructure. Negative differential resistance is observable at temperatures below 230 K, exhibiting a peak to valley ratio of 3:1 at 4.2 K. (author)

Initiatives for the energy renovation of single-family houses inDenmark evaluated on the basis of barriers and motivators

DEFF Research Database (Denmark)

Grøn Bjørneboe, Matilde; Svendsen, Svend; Heller, Alfred

2018-01-01

The renovation of single-family houses in Denmark is progressing only slowly. Changes in current pol-icy are needed if the political goal of a fossil-free building sector as part of a fossil-free society is to beachieved. Known barriers and motivators for energy renovation are identified, and arr......The renovation of single-family houses in Denmark is progressing only slowly. Changes in current pol-icy are needed if the political goal of a fossil-free building sector as part of a fossil-free society is to beachieved. Known barriers and motivators for energy renovation are identified......, suggestions are madefor improvement in four areas: (1) focus on non-energy benefits rather than investment, (2) enhance-ment of subsidy system, (3) including relevant renovation plans in the energy performance certificate(EPC), and (4) long-term regulation on the maximum allowed energy consumption of houses....

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)

Reflectionlessness, kurtosis and top curvature of potential barriers

International Nuclear Information System (INIS)

Ahmed, Zafar

2006-01-01

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

Numerical study of the influence of applied voltage on the current balance factor of single layer organic light-emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Lu, Fei-ping, E-mail: lufp-sysu@163.com; Liu, Xiao-bin; Xing, Yong-zhong [College of Physics and Information Science, Tianshui Normal University, Tianshui 741001 (China)

2014-04-28

Current balance factor (CBF) value, the ratio of the recombination current density and the total current density of a device, has an important function in fluorescence-based organic light-emitting diodes (OLEDs), as well as in the performance of the organic electrophosphorescent devices. This paper investigates the influence of the applied voltage of a device on the CBF value of single layer OLED based on the numerical model of a bipolar single layer OLED with organic layer trap free and without doping. Results show that the largest CBF value can be achieved when the electron injection barrier (ϕ{sub n}) is equal to the hole injection barrier (ϕ{sub p}) in the lower voltage region at any instance. The largest CBF in the higher voltage region can be achieved in the case of ϕ{sub n} > ϕ{sub p} under the condition of electron mobility (μ{sub 0n}) > hole mobility (μ{sub 0p}), whereas the result for the case of μ{sub 0n} < μ{sub 0p}, is opposite. The largest CBF when μ{sub 0n} = μ{sub 0p} can be achieved in the case of ϕ{sub n} = ϕ{sub p} in the entire region of the applied voltage. In addition, the CBF value of the device increases with increasing applied voltage. The results obtained in this paper can present an in-depth understanding of the OLED working mechanism and help in the future fabrication of high efficiency OLEDs.

Barriers to physical activity in chronic hemodialysis patients: a single-center pilot study in an Italian dialysis facility.

Science.gov (United States)

Fiaccadori, Enrico; Sabatino, Alice; Schito, Franco; Angella, Francesca; Malagoli, Martina; Tucci, Marco; Cupisti, Adamasco; Capitanini, Alessandro; Regolisti, Giuseppe

2014-01-01

In patients on chronic dialysis a sedentary lifestyle is a strong, yet potentially modifiable, predictor of mortality. The present single-center pilot study evaluated social, psychological and clinical barriers that may hinder physical activity in this population. We explored the association between barriers to physical activity and sedentarism in adult patients at a chronic dialysis facility in Parma, Italy. We used different questionnaries exploring participation in physical activity, physical functioning, patient attitudes and preferences, and barriers to physical activity perceived by either patients or dialysis doctors and nurses. We enrolled 104 patients, (67 males, 65%), mean age 69 years (79% of patients older than 60 years); median dialysis vintage 60 months (range 8-440); mean Charlson score 5.55, ADL (Activities of Daily Living) score 5.5. Ninety-two participants (88.5%) reported at least one barrier to physical activity. At multivariable analysis, after adjusting for age and sex, feeling to have too many medical problems (OR 2.99, 95% CI 1.27 to 7.07; P=0.012), chest pain (OR 10.78, 95% CI 1.28 to 90.28; P=0.029) and sadness (OR 2.59, 95% CI 1.10 to 6.09; P=0.030) were independently associated with physical inactivity. Lack of time for exercise counseling and the firm belief about low compliance/interest by the patients toward exercise were the most frequent barriers reported by doctors and nurses. We identified a number of patient-related and health personnel-related barriers to physical activity in patients on chronic dialysis. Solutions for these barriers should be addressed in future studies aimed at increasing the level of physical activity in this population. © 2014 S. Karger AG, Basel.

Study of the Wigner function at the device boundaries in one-dimensional single- and double-barrier structures

International Nuclear Information System (INIS)

Savio, Andrea; Poncet, Alain

2011-01-01

In this work, we compute the Wigner distribution function on one-dimensional devices from wave functions generated by solving the Schroedinger equation. Our goal is to investigate certain issues that we encountered in implementing Wigner transport equation solvers, such as the large discrepancies observed between the boundary conditions and the solution in the neighborhood of the boundaries. By evaluating the Wigner function without solving the Wigner transport equation, we intend to ensure that the actual boundary conditions are consistent with those commonly applied in literature. We study both single- and double-barrier unbiased structures. We use simple potential profiles, so that we can compute the wave functions analytically for better accuracy. We vary a number of structure geometry, material, meshing, and numerical parameters, among which are the contact length, the barrier height, the number of incident wave functions, and the numerical precision used for the computations, and we observe how the Wigner function at the device boundaries is affected. For the double-barrier structures, we look at the density matrix function and we study a model for the device transmission spectrum which helps explain the lobelike artifacts that we observe on the Wigner function.

Loy Yang A - Australia's largest privatisation

International Nuclear Information System (INIS)

Yenckin, C.

1997-01-01

The recent A$4,746 million privatisation of the 2000MW Loy Yang A power station and the Loy Yang coal mine by the Victorian Government is Australia's largest privatisation and one of 1997's largest project financing deals. (author)

Spin asymmetry calculations of the TMR-V curves in single and double-barrier magnetic tunnel junctions

KAUST Repository

Useinov, Arthur

2011-10-01

Spin-polarization asymmetry is the key parameter in asymmetric voltage behavior (AVB) of the tunnel magnetoresistance (TMR) in magnetic tunnel junctions. In this paper, we study the value of the TMR as a function of the applied voltage Va in the single as well as double barrier magnetic tunnel junctions (SMTJ & DMTJ, which are constructed from CoFeB/MgO interfaces) and numerically estimate the possible difference of the TMR-V a curves for negative and positive voltages in the homojunctions. As a result, we found that AVB may help to determine the exact values of Fermi wave vectors for minority and majority conducting spin sub-bands. Moreover, significant asymmetry of the experimental TMR-Va curves, which arises due to different annealing regimes, is explained by different heights of the tunnel barriers and values of the spin asymmetry. The numerical TMR-V a data are in good agreement with experimental ones. © 2011 IEEE.

Using Telepresence to Connect and Engage Classes and the Public in the Exploration of Tamu Massif, the World's Largest Single Volcano

Science.gov (United States)

Nanez-James, S. E.; Sager, W.

2016-02-01

Research published in 2013 showed that TAMU Massif, the largest mountain in the Shatsky Rise oceanic plateau, located approximately 1500 kilometers east of Japan, is the "World's Largest Single Volcano." This claim garnered widespread public interest and wonder concerning how something so big could remain so mysterious in the 21st century. This disconnect highlights the fact that oceans are still widely unexplored, especially the middle of the deep ocean. Because there is so much interest in TAMU Massif, a diverse outreach team lead by chief scientist Dr. William Sager from the University of Houston in partnership with the Texas State Aquarium and the Schmidt Ocean Institute (SOI) conducted a multifaceted ship-to-shore outreach project that included secondary school students, formal and informal educators, university students and professors, the aquarium and museum audience, and the general public. The objective was to work in conjunction with SOI and various other partners, including the Texas Regional Collaborative, the Aquarium of the Pacific, and the Houston Museum of Natural Science, to promote science and ocean literacy while inspiring future scientists - especially those from underserved and underrepresented groups - through ocean connections. Participants were connected through live ship-to-shore distance learning broadcasts of ongoing marine research and discovery of TAMU Massif aboard the R/V Falkor, allowing audiences to participate in real-time research and apply real world science to curriculum in the classrooms. These ship-to-shore presentations connected to existing curriculums and standards, lessons, and career interests of the students and educators with special teacher events and professional development workshops conducted from aboard the R/V Falkor.

Largest case series of Latin American eyelid tumors over 13-Years from a single center in Sao Paulo, Brazil

Directory of Open Access Journals (Sweden)

Jéssica Carolinne Damasceno

Full Text Available ABSTRACT Purpose: Malignant lesions of the eyelid are the most common eye cancers. Although rarely lethal, late diagnosis can lead to serious visual morbidity. Definitive diagnosis of neoplastic lesions is pathological. Indications and types of eyelid lesions in a single high-volume ophthalmic reference center in Sao Paulo, Brazil, were analyzed. Methods: The surgical pathological reports of patients who underwent eye removal procedures between January 2000 and December 2012 were retrieved from the electronic database of the Ophthalmology Department and retrospectively reviewed. Data regarding the final anatomopathological diagnosis, sex, and age were analyzed via the χ2 test with Yates' correction. Results: Of the 1,113 eyelid tumors resected over the 13-year study period, 324 (29% lesions were malignant. The most prevalent lesions were basal cell, squamous cell, and sebaceous gland carcinomas. The median ages of patients (females, n=165, 51%; males, n=159, 49% with a diagnosis of basal cell, squamous cell, and sebaceous gland carcinomas were 65, 75, and 70 years, respectively. Conclusion: This is the largest retrospective cohort analysis of eyelid tumors in a Latin American population. These findings are in agreement with those from large centers in other countries and regions.

Tuning anisotropy barriers in a family of tetrairon(III) single-molecule magnets with an S = 5 ground state.

Science.gov (United States)

Accorsi, Stefania; Barra, Anne-Laure; Caneschi, Andrea; Chastanet, Guillaume; Cornia, Andrea; Fabretti, Antonio C; Gatteschi, Dante; Mortalo, Cecilia; Olivieri, Emiliano; Parenti, Francesca; Rosa, Patrick; Sessoli, Roberta; Sorace, Lorenzo; Wernsdorfer, Wolfgang; Zobbi, Laura

2006-04-12

Tetrairon(III) Single-Molecule Magnets (SMMs) with a propeller-like structure exhibit tuneable magnetic anisotropy barriers in both height and shape. The clusters [Fe4(L1)2(dpm)6] (1), [Fe4(L2)2(dpm)6] (2), [Fe4(L3)2(dpm)6].Et2O (3.Et2O), and [Fe4(OEt)3(L4)(dpm)6] (4) have been prepared by reaction of [Fe4(OMe)6(dpm)6] (5) with tripodal ligands R-C(CH2OH)3 (H3L1, R = Me; H3L2, R = CH2Br; H3L3, R = Ph; H3L4, R = tBu; Hdpm = dipivaloylmethane). The iron(III) ions exhibit a centered-triangular topology and are linked by six alkoxo bridges, which propagate antiferromagnetic interactions resulting in an S = 5 ground spin state. Single crystals of 4 reproducibly contain at least two geometric isomers. From high-frequency EPR studies, the axial zero-field splitting parameter (D) is invariably negative, as found in 5 (D = -0.21 cm(-1)) and amounts to -0.445 cm(-1) in 1, -0.432 cm(-1) in 2, -0.42 cm(-1) in 3.Et2O, and -0.27 cm(-1) in 4 (dominant isomer). The anisotropy barrier Ueff determined by AC magnetic susceptibility measurements is Ueff/kB = 17.0 K in 1, 16.6 K in 2, 15.6 K in 3.Et2O, 5.95 K in 4, and 3.5 K in 5. Both |D| and U(eff) are found to increase with increasing helical pitch of the Fe(O2Fe)3 core. The fourth-order longitudinal anisotropy parameter B4(0), which affects the shape of the anisotropy barrier, concomitantly changes from positive in 1 ("compressed parabola") to negative in 5 ("stretched parabola"). With the aid of spin Hamiltonian calculations the observed trends have been attributed to fine modulation of single-ion anisotropies induced by a change of helical pitch.

T-TY Tank Farm Interim Surface Barrier Demonstration - Vadose Zone Monitoring Plan

International Nuclear Information System (INIS)

Zhang, Z.F.; Strickland, Christopher E.; Field, Jim G.; Parker, Danny L.

2010-01-01

The Hanford Site has 149 underground single-shell tanks that store hazardous radioactive waste. Many of these tanks and their associated infrastructure (e.g., pipelines, diversion boxes) have leaked. Some of the leaked waste has entered the groundwater. The largest known leak occurred from the T-106 Tank of the 241-T Tank Farm in 1973. Five tanks are assumed to have leaked in the TY Farm. Many of the contaminants from those leaks still reside within the vadose zone within the T and TY Tank Farms. The Department of Energy's Office of River Protection seeks to minimize the movement of these contaminant plumes by placing interim barriers on the ground surface. Such barriers are expected to prevent infiltrating water from reaching the plumes and moving them further. The soil water regime is monitored to determine the effectiveness of the interim surface barriers. Soil-water content and water pressure are monitored using off-the-shelf equipment that can be installed by the hydraulic hammer technique. Four instrument nests were installed in the T Farm in fiscal year (FY) 2006 and FY2007; two nests were installed in the TY Farm in FY2010. Each instrument nest contains a neutron probe access tube, a capacitance probe, and four heat-dissipation units. A meteorological station has been installed at the north side of the fence of the T Farm. This document summarizes the monitoring methods, the instrument calibration and installation, and the vadose zone monitoring plan for interim barriers in T farm and TY Farm.

Barriers for Energy Renovation of Danish Single-Family Houses and Suggested Solutions to Overcome These

DEFF Research Database (Denmark)

Mortensen, Andrea; Heiselberg, Per; Knudstrup, Mary-Ann

2011-01-01

As much as 40% of the total energy consumption in Denmark is utilized by the building sector and most of this energy is used for heating. Political initiatives have been taken to reduce this amount considerably but for this to happen, the energy consumption of the existing residential housing stock...... must be reduced dramatically. The greatest saving potential is found among the approximately 440.000 standardised single-family houses which were constructed in the 1960’s and 1970’s. It is found that barriers preventing the implementation of this great potential are present in various forms among all...

Tunnel superpenetrability of potential barriers

International Nuclear Information System (INIS)

Zakhariev, B N.

1982-01-01

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

Investigation of airflow effects on the dielectric barrier discharge with single/double discharge channel arrangement

Science.gov (United States)

Fan, Zhihui; Yan, Huijie; Liu, Yidi; Guo, Hongfei; Wang, Yuying; Ren, Chunsheng

2018-05-01

Atmospheric-pressure dielectric barrier discharge (DBD) with airflow participation has been widely used in recent years. In this paper, effects of airflow on DBD characteristics are experimentally investigated by single/double pin-to-plate DBD arrangements with an AC exciting source. The discharge electrical characteristics and the movements of discharge channels in airflow are investigated with a single pin electrode arrangement. The current intensities increase in positive cycles and decrease in negative cycles with the increase in airflow velocity. The transition from a filamentary discharge to a diffuse discharge is observed under certain airflow conditions, and the discharge channels move with the airflow with a movement velocity less than the corresponding airflow velocity. In the cases of double pin electrode arrangements, the repulsion between double pin discharge channels is apparent at a 10 mm distance but is not obvious at a 20 mm distance. When the airflow is introduced into the discharge gap, not as in the case of single pin electrode arrangement, the movements of discharge channels in airflow are affected by adjacent discharge channels. The corresponding reasons are analyzed in the paper.

BARRIERS OF STRATEGIC ALLIANCES ORGANIZATION

Directory of Open Access Journals (Sweden)

Vladislav M. Sannikov

2014-01-01

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

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.

Development of CdTe/Cd{sub 1-x}Mg{sub x}Te double barrier, single quantum well heterostructure for resonant tunneling

Energy Technology Data Exchange (ETDEWEB)

Reuscher, G.; Keim, M.; Fischer, F.; Waag, A.; Landwehr, G. [Physikalishes Institut der Universitaet Wuerzburg am Hubland, Wuerzburg (Germany)

1995-12-31

We report the first observation of resonant tunneling through a CdTe/Cd{sub 1-x}Mg{sub x}Te double barrier, single quantum well heterostructure. Negative differential resistance is observable at temperatures below 230 K, exhibiting a peak to valley ratio of 3:1 at 4.2 K. (author). 16 refs, 2 figs.

Schottky barrier MOSFET systems and fabrication thereof

Science.gov (United States)

Welch, J.D.

1997-09-02

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

Future Directions for Transuranic Single Molecule Magnets

Directory of Open Access Journals (Sweden)

Nicola Magnani

2018-02-01

Full Text Available Single Molecule Magnets (SMMs based on transition metals and rare earths have been the object of considerable attention for the past 25 years. These systems exhibit slow relaxation of the magnetization, arising from a sizeable anisotropy barrier, and magnetic hysteresis of purely molecular origin below a given blocking temperature. Despite initial predictions that SMMs based on 5f-block elements could outperform most others, the results obtained so far have not met expectations. Exploiting the versatile chemistry of actinides and their favorable intrinsic magnetic properties proved, indeed, to be more difficult than assumed. However, the large majority of studies reported so far have been dedicated to uranium molecules, thus leaving the largest part of the 5f-block practically unexplored. Here, we present a short review of the progress achieved up to now and discuss some options for a possible way forward.

Could tight junctions regulate the barrier function of the aged skin?

Science.gov (United States)

Svoboda, Marek; Bílková, Zuzana; Muthný, Tomáš

2016-03-01

The skin is known to be the largest organ in human organism creating interface with outer environment. The skin provides protective barrier against pathogens, physical and chemical insults, and against uncontrolled loss of water. The barrier function was primarily attributed to the stratum corneum (SC) but recent studies confirmed that epidermal tight junctions (TJs) also play important role in maintaining barrier properties of the skin. Independent observations indicate that barrier function and its recovery is impaired in aged skin. However, trans-epidermal water loss (TEWL) values remains rather unchanged in elderly population. UV radiation as major factor of photoageing impairs TJ proteins, but TJs have great self-regenerative potential. Since it may be possible that TJs can compensate TEWL in elderly due to its regenerative and compensatory capabilities, important question remains to be answered: how are TJs regulated during skin ageing? This review provides an insight into TJs functioning as epidermal barrier and summarizes current knowledge about the impact of ageing on the barrier function of the skin and epidermal TJs. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Magnetization reversal processes of single nanomagnets and their energy barrier

International Nuclear Information System (INIS)

Krone, P.; Makarov, D.; Albrecht, M.; Schrefl, T.; Suess, D.

2010-01-01

Micromagnetic simulations were performed to investigate the influence of geometry and magnetic anisotropy constant on energy barrier and magnetization reversal mechanism of individual bits important for the bit patterned media concept in magnetic data storage. It is shown that dependency of the energy barrier on magnetic and geometric properties of bits can be described by an analytical approach in the case of quasi-coherent magnetization rotation process. However, when the bit size exceeds a critical size, for which an incoherent magnetization reversal is preferred, the analytical approach becomes invalid and no self-consistent theory is available. By systematically investigating the influence of bit size on the magnetization reversal mode, it was found that the transition from quasi-coherent to incoherent magnetization reversal mode can still be described analytically if an activation volume is considered instead of the bit volume. In this case, the nucleation volume is an important parameter determining thermal stability of the bit. If the volume of the bit is larger than twice the activation volume, the energy barrier stays nearly constant; with further increase in bit size, no gain in thermal stability can be achieved.

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

Identification and analysis of reverse logistics barriers using fuzzy Delphi method and AHP

DEFF Research Database (Denmark)

Bouzon, Marina; Govindan, Kannan; Rodriguez, Carlos M Taboada

2016-01-01

enacted National Policy on solid waste. To bridge this gap, this paper identifies and evaluates the barriers for RL in the Brazilian context. An eleven-step research methodology is proposed. First, literature was thoroughly reviewed. fuzzy Delphi method (FDM) was used to obtain the critical list...... a systematic literature review process, a list of most common RL barriers accepted by Brazilian organizations, and a priority ranking of RL barriers for the electrical-electronic industry sector in Brazil. The "Economic related issues" category of barriers seems to be the first priority. The financial burden...... the reverse flow must be taken. However, most existing research on the barriers for RL implementation is focused on developed countries. Among the most important emerging economies, Brazil, the largest Latin America economy, faces challenges such as a deficient logistics infrastructure and the recently...

Measurement and statistical analysis of single-molecule current-voltage characteristics, transition voltage spectroscopy, and tunneling barrier height.

Science.gov (United States)

Guo, Shaoyin; Hihath, Joshua; Díez-Pérez, Ismael; Tao, Nongjian

2011-11-30

We report on the measurement and statistical study of thousands of current-voltage characteristics and transition voltage spectra (TVS) of single-molecule junctions with different contact geometries that are rapidly acquired using a new break junction method at room temperature. This capability allows one to obtain current-voltage, conductance voltage, and transition voltage histograms, thus adding a new dimension to the previous conductance histogram analysis at a fixed low-bias voltage for single molecules. This method confirms the low-bias conductance values of alkanedithiols and biphenyldithiol reported in literature. However, at high biases the current shows large nonlinearity and asymmetry, and TVS allows for the determination of a critically important parameter, the tunneling barrier height or energy level alignment between the molecule and the electrodes of single-molecule junctions. The energy level alignment is found to depend on the molecule and also on the contact geometry, revealing the role of contact geometry in both the contact resistance and energy level alignment of a molecular junction. Detailed statistical analysis further reveals that, despite the dependence of the energy level alignment on contact geometry, the variation in single-molecule conductance is primarily due to contact resistance rather than variations in the energy level alignment.

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)

Comfort and microbial barrier properties of garments worn next to the skin

Science.gov (United States)

Kopitar, D.; Rogina-Car, B.; Skenderi, Z.

2017-10-01

Compared with viscose fibre, modal fibre is characterized by some advantageous properties such as higher dry and wet tenacities, higher wet modulus, lower water retention capacity and lower level of swelling. Impact of different knitted fabric structure made of cotton and 97 % CMD/3 % EL fibres on thermo-physiological comfort and microbial barrier properties were investigated. All knitted fabrics have very good physiological properties. The microbial barrier permeability of knitted fabric after extreme contamination with bacterial spores in dry state showed that double jersey offered more effective microbial barrier than the single jersey knitted fabrics respectively the greater thickness of double jersey knitted fabric provide more difficult barrier to bacterial spores to pass. In wet state all knitted fabrics have more effective microbial barrier which could be explained by cellulose fibres swelling. In wet state 97 % CMD/3 % EL single jersey knitted fabric have more effective microbial barrier then cotton double and single jersey knitted fabrics.

Schottky barrier diode based on β-Ga2O3 (100) single crystal substrate and its temperature-dependent electrical characteristics

Science.gov (United States)

He, Qiming; Mu, Wenxiang; Dong, Hang; Long, Shibing; Jia, Zhitai; Lv, Hangbing; Liu, Qi; Tang, Minghua; Tao, Xutang; Liu, Ming

2017-02-01

The Pt/β-Ga2O3 Schottky barrier diode and its temperature-dependent current-voltage characteristics were investigated for power device application. The edge-defined film-fed growth (EFG) technique was utilized to grow the (100)-oriented β-Ga2O3 single crystal substrate that shows good crystal quality characterized by X-ray diffraction and high resolution transmission electron microscope. Ohmic and Schottky electrodes were fabricated by depositing Ti and Pt metals on the two surfaces, respectively. Through the current-voltage (I-V) measurement under different temperature and the thermionic emission modeling, the fabricated Pt/β-Ga2O3 Schottky diode was found to show good performances at room temperature, including rectification ratio of 1010, ideality factor (n) of 1.1, Schottky barrier height (ΦB) of 1.39 eV, threshold voltage (Vbi) of 1.07 V, ON-resistance (RON) of 12.5 mΩ.cm2, forward current density at 2 V (J@2V) of 56 A/cm2, and saturation current density (J0) of 2 × 10-16 A/cm2. The effective donor concentration Nd - Na was calculated to be about 2.3 × 1014 cm3. Good temperature dependent performance was also found in the device. The Schottky barrier height was estimated to be about 1.3 eV-1.39 eV at temperatures ranging from room temperature to 150 °C. With increasing temperature, parameters such as RON and J@2V become better, proving that the diode can work well at high temperature. The EFG grown β-Ga2O3 single crystal is a promising material to be used in the power devices.

Extraction of water labeled with oxygen 15 during single-capillary transit. Influence of blood pressure, osmolarity, and blood-brain barrier damage

International Nuclear Information System (INIS)

Go, K.G.; Lammertsma, A.A.; Paans, A.M.; Vaalburg, W.; Woldring, M.G.

1981-01-01

By external detection, the influence of arterial blood pressure (BP), osmolarity, and cold-induced blood-brain barrier damage was assessed on the extraction of water labeled with oxygen 15 during single-capillary transit in the rat. There was an inverse relation between arterial BP and extraction that was attributable to the influence of arterial BP on cerebral blood flow (CBF) and the relation between CBF and extraction. Neither arterial BP nor osmolarity of the injected bolus had any direct effect on extraction of water 15O, signifying that the diffusional exchange component (determined by blood flow) of extraction greatly surpasses the convection flow contribution by hydrostatic or osmotic forces. Damage to the blood-brain barrier did not change its permeability to water

Thermal barrier coatings with a double-layer bond coat on Ni{sub 3}Al based single-crystal superalloy

Energy Technology Data Exchange (ETDEWEB)

Zhou, Xin [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Xu, Zhenhua; Mu, Rende [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); He, Limin, E-mail: he_limin@yahoo.com [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Huang, Guanghong [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Cao, Xueqiang, E-mail: xcao@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2014-04-05

Highlights: • Thermal barrier coatings with a double-layer bond coat of (Ni,Pt)Al and NiCrAlYSi. • Good adherence at all interfaces within TBC system. • The underlying (Ni,Pt)Al layer can supply abundant Al content for the upper NiCrAlYSi layer. • Crack nucleation, propagation and coalescence lead to the failure of coating. -- Abstract: Electron-beam physical vapor deposited thermal barrier coatings (TBCs) with a double-layer bond coat of (Ni,Pt)Al and NiCrAlYSi were prepared on a Ni{sub 3}Al based single-crystal superalloy. Phase and cross-sectional microstructure of the developed coatings were studied by using X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The experimental results show good adherence at all interfaces within this system. Furthermore, oxidation resistance and elements interdiffusion behavior of the double-layer bond coat were also investigated. The double-layer bond coat system exhibits a better scale adherence than the single layer bond coat systems since the underlying (Ni,Pt)Al layer can supply abundant Al for the upper NiCrAlYSi layer. Finally, thermal cycling behavior of the double-layer bond coat TBC was evaluated and the failure mechanism was discussed. Crack nucleation, propagation and coalescence caused by TGO growth stress and the thermal expansion mismatch stress between TGO and bond coat can be mainly responsible for the spallation of this coating.

Delay time in a single barrier for a movable quantum shutter

International Nuclear Information System (INIS)

Hernandez, Alberto

2010-01-01

The transient solution and delay time for a δ potential scatterer with a movable quantum shutter is calculated by solving analytically the time-dependent Schroedinger equation. The delay time is analyzed as a function of the distance between the shutter and the potential barrier and also as a function of the distance between the potential barrier and the detector. In both cases, it is found that the delay time exhibits a dynamical behavior and that it tends to a saturation value Δt sat in the limit of very short distances, which represents the maximum delay produced by the potential barrier near the interaction region. The phase time τ θ , on the other hand, is not an appropriate time scale for measuring the time delay near the interaction region, except if the shutter is moved far away from the potential. The role played by the antibound state of the system on the behavior of the delay time is also discussed.

Selective arc-discharge synthesis of Dy2S-clusterfullerenes and their isomer-dependent single molecule magnetism.

Science.gov (United States)

Chen, Chia-Hsiang; Krylov, Denis S; Avdoshenko, Stanislav M; Liu, Fupin; Spree, Lukas; Yadav, Ravi; Alvertis, Antonis; Hozoi, Liviu; Nenkov, Konstantin; Kostanyan, Aram; Greber, Thomas; Wolter, Anja U B; Popov, Alexey A

2017-09-01

A method for the selective synthesis of sulfide clusterfullerenes Dy 2 S@C 2 n is developed. Addition of methane to the reactive atmosphere reduces the formation of empty fullerenes in the arc-discharge synthesis, whereas the use of Dy 2 S 3 as a source of metal and sulfur affords sulfide clusterfullerenes as the main fullerene products along with smaller amounts of carbide clusterfullerenes. Two isomers of Dy 2 S@C 82 with C s (6) and C 3v (8) cage symmetry, Dy 2 S@C 72 - C s (10528), and a carbide clusterfullerene Dy 2 C 2 @C 82 - C s (6) were isolated. The molecular structure of both Dy 2 S@C 82 isomers was elucidated by single-crystal X-ray diffraction. SQUID magnetometry demonstrates that all of these clusterfullerenes exhibit hysteresis of magnetization, with Dy 2 S@C 82 - C 3v (8) being the strongest single molecule magnet in the series. DC- and AC-susceptibility measurements were used to determine magnetization relaxation times in the temperature range from 1.6 K to 70 K. Unprecedented magnetization relaxation dynamics with three consequent Orbach processes and energy barriers of 10.5, 48, and 1232 K are determined for Dy 2 S@C 82 - C 3v (8). Dy 2 S@C 82 - C s (6) exhibits faster relaxation of magnetization with two barriers of 15.2 and 523 K. Ab initio calculations were used to interpret experimental data and compare the Dy-sulfide clusterfullerenes to other Dy-clusterfullerenes. The smallest and largest barriers are ascribed to the exchange/dipolar barrier and relaxation via crystal-field states, respectively, whereas an intermediate energy barrier of 48 K in Dy 2 S@C 82 - C 3v (8) is assigned to the local phonon mode, corresponding to the librational motion of the Dy 2 S cluster inside the carbon cage.

Barriers to improvements in energy efficiency

Energy Technology Data Exchange (ETDEWEB)

Reddy, A.K.N.

1991-10-01

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

Barriers to improvements in energy efficiency

Energy Technology Data Exchange (ETDEWEB)

Reddy, A.K.N.

1991-10-01

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

Study on fusion potential barrier in heavy ion reactions based on the dynamical model

International Nuclear Information System (INIS)

Tian Junlong; Wu Xizhen; Li Zhuxia; Wang Ning; Liu Fuhu

2004-01-01

Based on an improved quantum molecular dynamics model the static and dynamic potential in the entrance channel of synthesis of superheavy nuclei are studied. The dependence of the static potential (and driving potential) on mass-asymmetry is obtained. From this study authors find out that the mass-symmetric system seems to be difficult to fuse and the fusing system with the largest driving potential could be the optimal choice of the projectile-target combination. By comparing the static potential barrier with the dynamic one authors find that the latter one is lower than former one obviously, and that the dynamical potential barrier is entrance energy dependent. The maximum and minimum of dynamic potential barriers approach to the diabatic (sudden approximation) and the adiabatic static potential barriers, respectively

Largest College Endowments, 2011

Science.gov (United States)

Chronicle of Higher Education, 2012

2012-01-01

Of all endowments valued at more than $250-million, the UCLA Foundation had the highest rate of growth over the previous year, at 49 percent. This article presents a table of the largest college endowments in 2011. The table covers the "rank," "institution," "market value as of June 30, 2011," and "1-year change" of institutions participating in…

An examination of how women and underrepresented racial/ethnic minorities experience barriers in biomedical research and medical programs

Science.gov (United States)

Chakraverty, Devasmita

Women in medicine and biomedical research often face challenges to their retention, promotion, and advancement to leadership positions (McPhillips et al., 2007); they take longer to advance their careers, tend to serve at less research-intensive institutions and have shorter tenures compared to their male colleagues (White, McDade, Yamagata, & Morahan, 2012). Additionally, Blacks and Hispanics are the two largest minority groups that are vastly underrepresented in medicine and biomedical research in the United States (AAMC, 2012; NSF, 2011). The purpose of this study is to examine specific barriers reported by students and post-degree professionals in the field through the following questions: 1. How do women who are either currently enrolled or graduated from biomedical research or medical programs define and make meaning of gender-roles as academic barriers? 2. How do underrepresented groups in medical schools and biomedical research institutions define and make meaning of the academic barriers they face and the challenges these barriers pose to their success as individuals in the program? These questions were qualitatively analyzed using 146 interviews from Project TrEMUR applying grounded theory. Reported gender-role barriers were explained using the "Condition-Process-Outcome" theoretical framework. About one-third of the females (across all three programs; majority White or Black between 25-35 years of age) reported gender-role barriers, mostly due to poor mentoring, time constraints, set expectations and institutional barriers. Certain barriers act as conditions, causing gender-role issues, and gender-role issues influence certain barriers that act as outcomes. Strategies to overcome barriers included interventions mostly at the institutional level (mentor support, proper specialty selection, selecting academia over medicine). Barrier analysis for the two largest URM groups indicated that, while Blacks most frequently reported racism, gender barriers

Socio-demographic and behavioral variation in barriers to leisure-time physical activity.

Science.gov (United States)

Borodulin, Katja; Sipilä, Noora; Rahkonen, Ossi; Leino-Arjas, Päivi; Kestilä, Laura; Jousilahti, Pekka; Prättälä, Ritva

2016-02-01

We examined the socio-demographic and behavioral determinants of perceived barriers to leisure-time physical activity (LTPA) in a population-based sample of working-aged adults. Data comprised the National FINRISK 2002 Study, a population-based health examination study. Analyses were restricted to those aged 25-64 years and who perceived that their amount of LTPA did not reach sufficient levels. They reported barriers to LTPA, defined as a lack of time, motivation and lack of companionship to be active with, as well as high expenses. Age, education, household income, employment status, family type, physical activity, smoking and body mass index (BMI) were included as explanatory variables. Lack of time was the most frequent barrier. Each barrier was explained by a different set of factors that also varied between genders. The strongest and most systematic associations with the barriers were found for age, employment status and family type. Lack of time was less often reported as a barrier among the unemployed, singles without children and older people. Lacking motivation as a barrier was most common among singles without children. High expenses as a barrier was more often reported by the unemployed, and less often reported in the highest income group. When considering actions to promote LTPA, there is not one single solution, because the perceived barriers vary by population subgroups. © 2015 the Nordic Societies of Public Health.

Analysis of interactions among the barriers to energy saving in China

International Nuclear Information System (INIS)

Wang Guohong; Wang Yunxia; Zhao Tao

2008-01-01

Since China became the second largest energy consumer and carbon dioxide emitter, the problem of energy consumption and environmental pollution has drawn the world's attention. Meanwhile, Chinese government has put high emphasis on the problem. One project of energy saving initiated by Chinese government has been put into practice. However, many difficulties need to be dealt with to meet the expected aim of social development. The objective of this article is to investigate the interactions among the major barriers which prevent the practice of energy saving in China. Obviously, a clear definition of relationships among the barriers to energy saving helps top leaders make relevant decisions to solve the problem of economic sustainability, energy security and environment pollution in the future. To date, studies specifying energy-saving barriers have often focused on analyzing these barriers separately. As a result, a holistic view in understanding the barriers to energy-saving project is lacking. Interpretive structural modeling (ISM) is utilized to summarize the critical barriers hindering the project of energy saving in China and to explain the interrelationships among them. Suggestions for energy-saving practice and future research are provided

Entering the United States Federal Procurement Market: success factors and barriers for foreign firms.

NARCIS (Netherlands)

Vehof, Tim; Telgen, Jan; Ruel, Hubertus Johannes Maria; Ruel, H.J.M.

2012-01-01

The US federal procurement market is the largest procurement market in the world. Therefore, it is an attractive market for foreign companies to enter. Existing literature indicates the success factors and barriers for public procurement market entry in general, however not for the US procurement

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

Science.gov (United States)

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

2016-04-01

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

Largest particle detector nearing completion

CERN Multimedia

2006-01-01

"Construction of another part of the Large Hadron Collider (LHC), the worl's largest particle accelerator at CERN in Switzerland, is nearing completion. The Compact Muon Solenoid (CMS) is oner of the LHC project's four large particle detectors. (1/2 page)

Role of intestinal mucosal barrier in the development and progression of nonalcoholic fatty liver disease

Directory of Open Access Journals (Sweden)

ZHANG Yuanyuan

2016-12-01

Full Text Available The incidence of non-alcoholic fatty liver disease (NAFLD has been increasing year by year in China. Intestinal mucosa is the largest organ for bacterial storage, and intestinal mucosal barrier includes biological barrier, mechanical barrier, immunological barrier, and chemical barrier. This article investigates the important role of intestinal mucosal barrier function in the pathogenesis of NAFLD. As for the intestinal biological barrier, abnormalities in gut microbiota occur earlier than obesity and other metabolic disorders; small intestinal bacterial overgrowth may affect energy metabolism, promote insulin resistance, and get involved in the pathogenesis of NAFLD; regulation of gut microbiota has a certain clinical effect in the treatment of NAFLD. Intestinal mechanical barrier impairment increases the mucosal permeability and is associated with intestinal dysbacteriosis. The changes in intestinal immunological barrier may be associated with obesity, metabolic disorders, and liver inflammation. The changes in intestinal chemical barrier can inhibit the synthesis and secretion of very low-density lipoprotein and low-density lipoprotein in hepatocytes and may result in triglyceride deposition in the liver. It is pointed out that the research on intestinal mucosal barrier function provides promising prospects for the prevention and treatment of NAFLD.

The transition mechanism from a symmetric single period discharge to a period-doubling discharge in atmospheric helium dielectric-barrier discharge

International Nuclear Information System (INIS)

Zhang, Dingzong; Wang, Yanhui; Wang, Dezhen

2013-01-01

Period-doubling and chaos phenomenon have been frequently observed in atmospheric-pressure dielectric-barrier discharges. However, how a normal single period discharge bifurcates into period-doubling state is still unclear. In this paper, by changing the driving frequency, we study numerically the transition mechanisms from a normal single period discharge to a period-doubling state using a one-dimensional self-consistent fluid model. The results show that before a discharge bifurcates into a period-doubling state, it first deviates from its normal operation and transforms into an asymmetric single period discharge mode. Then the weaker discharge in this asymmetric discharge will be enhanced gradually with increasing of the frequency until it makes the subsequent discharge weaken and results in the discharge entering a period-doubling state. In the whole transition process, the spatial distribution of the charged particle density and the electric field plays a definitive role. The conclusions are further confirmed by changing the gap width and the amplitude of the applied voltage

The transition mechanism from a symmetric single period discharge to a period-doubling discharge in atmospheric helium dielectric-barrier discharge

Energy Technology Data Exchange (ETDEWEB)

Zhang, Dingzong; Wang, Yanhui; Wang, Dezhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2013-06-15

Period-doubling and chaos phenomenon have been frequently observed in atmospheric-pressure dielectric-barrier discharges. However, how a normal single period discharge bifurcates into period-doubling state is still unclear. In this paper, by changing the driving frequency, we study numerically the transition mechanisms from a normal single period discharge to a period-doubling state using a one-dimensional self-consistent fluid model. The results show that before a discharge bifurcates into a period-doubling state, it first deviates from its normal operation and transforms into an asymmetric single period discharge mode. Then the weaker discharge in this asymmetric discharge will be enhanced gradually with increasing of the frequency until it makes the subsequent discharge weaken and results in the discharge entering a period-doubling state. In the whole transition process, the spatial distribution of the charged particle density and the electric field plays a definitive role. The conclusions are further confirmed by changing the gap width and the amplitude of the applied voltage.

Single Particle Entropy in Heated Nuclei

International Nuclear Information System (INIS)

Guttormsen, M.; Chankova, R.; Hjorth-Jensen, M.; Rekstad, J.; Siem, S.; Sunde, A. C.; Syed, N. U. H.; Agvaanluvsan, U.; Schiller, A.; Voinov, A.

2006-01-01

The thermal motion of single particles represents the largest contribution to level density (or entropy) in atomic nuclei. The concept of single particle entropy is presented and shown to be an approximate extensive (additive) quantity for mid-shell nuclei. A few applications of single particle entropy are demonstrated

Barrier bucket experiment at the AGS

Directory of Open Access Journals (Sweden)

M. Fujieda

1999-12-01

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

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

Alternative Fuels Data Center: America's Largest Home Runs on Biodiesel in

Science.gov (United States)

North Carolina America's Largest Home Runs on Biodiesel in North Carolina to someone by E-mail Share Alternative Fuels Data Center: America's Largest Home Runs on Biodiesel in North Carolina on Facebook Tweet about Alternative Fuels Data Center: America's Largest Home Runs on Biodiesel in North

Electrical and mechanical properties of Bi-2223/Ag/barrier/Ag composite tapes

International Nuclear Information System (INIS)

Kovac, P.; Husek, I.; Goemoery, F.; Oduleye, O.O.; Alford, N.McN.; Pachla, W.; Diduszko, R.

2000-01-01

Bi-2223/Ag/barrier/Ag single-core tapes with various oxide barrier materials (BaZrO 3 , SrCO 3 , ZrO 2 and Al 2 O 3 ) have been prepared by PIT. The I-V curves and ac susceptibility measurements have been performed for tapes with identical heat treatment history. Young's moduli of these tape samples have been evaluated by three-point bending and the structure of barrier powders and BSCCO cores was analysed by SEM and XRD, respectively. It was found that the shape of I-V curves, the current transfer lengths and the mechanical properties of tapes are all affected by the oxide barrier type and the barrier thickness, as well as by its porosity and uniformity. This is because the oxide barrier controls the oxygen diffusion during the tape heat treatment and simultaneously the HTS phase formation kinetics, its purity and content within the superconducting core. On the base of the results obtained for single-core tapes, two kinds of multifilamentary composite were made and tested. (author)

Identifying the node spreading influence with largest k-core values

International Nuclear Information System (INIS)

Lin, Jian-Hong; Guo, Qiang; Dong, Wen-Zhao; Tang, Li-Ying; Liu, Jian-Guo

2014-01-01

Identifying the nodes with largest spreading influence of complex networks is one of the most promising domains. By taking into account the neighbors' k-core values, we present an improved neighbors' k-core (INK) method which is the sum of the neighbors' k-core values with a tunable parameter α to evaluate the node spreading influence with largest k-core values. Comparing with the Susceptible–Infected–Recovered (SIR) results for four real networks, the INK method could identify the node spreading influence with largest k-core values more accurately than the ones generated by the degree k, closeness C, betweenness B and coreness centrality method. - Highlights: • We present an improved neighbors' k-core (INK) method to evaluate the node spreading influence with largest k-core values. • The INK method could identify the node spreading influence with largest k-core values more accurately. • Kendall's tau τ of INK method with α=1 are highly identical to rank the node influence

Preparing Europe for a single market in energy

International Nuclear Information System (INIS)

Anon.

1990-01-01

By the end of 1992 a ''single market'' in the European Community should be in place. While the energy sector was not included in the ''White Paper'' which planned the single market, it soon became obvious that it could not be excluded. The single market in energy is intended to integrate energy supply in the member states and remove barriers to trade. It has been calculated that these barriers cost the Community 20-30 billion ecus ($15-20 billion) every year. Removing the barriers will result in much greater competition within the energy market. The Commission published a working document, the internal energy market, in May 1988. This report described the real and potential obstacles to the single energy market for each of the principal energy sources and suggested priorities which should be addressed. The strategy suggested in the report is outlined here, and recent developments briefly reviewed. (author)

CERN tests largest superconducting solenoid magnet

CERN Multimedia

2006-01-01

"CERN's Compacts Muon Solenoid (CMS) - the world's largest superconducting solenoid magnet - has reached full field in testing. The instrument is part of the proton-proton Large Hadron Collider (LHC) project, located in a giant subterranean chamber at Cessy on the Franco-Swiss border." (1 page)

Effects of Thermal Exposure on Structures of DD6 Single Crystal Superalloy with Thermal Barrier Coatings

Directory of Open Access Journals (Sweden)

DONG Jianmin

2016-10-01

Full Text Available In order to investigate the effect of water grit-blasting and high temperature thermal exposure on the microstructures of DD6 alloy with TBCs, DD6 single crystal superalloy specimens were water grit-blasted with 0.3 MPa pressure, then the specimens were coated with thermal barrier coatings by electron beam physical vapor deposition (EB-PVD. Specimens with TBCs were exposed at 1100℃ for 50 and 100 hours in the air respectively, and then these specimens were subjected to stress-rupture tests under the condition of 1100℃/130 MPa. The results show that grit-blasting doesn't lead into the recrystallization, thermal exposure can induce element interdiffusion between the bond coat and alloy substrate, the residual stress and element diffusion lead into the changes of γ' phase coarsing direction. After stress rupture tests, the secondary reaction zone emerges into a local area.

Intestinal epithelial barrier function and tight junction proteins with heat and exercise

DEFF Research Database (Denmark)

Dokladny, Karol; Zuhl, Micah N; Moseley, Pope L

2016-01-01

A single layer of enterocytes and tight junctions (intercellular multiprotein complexes) form the intestinal epithelial barrier that controls transport of molecules through transcellular and paracellular pathways. A dysfunctional or "leaky" intestinal tight junction barrier allows augmented perme...

Barriers to Cleft Lip and Palate Repair Around the World.

Science.gov (United States)

Massenburg, Benjamin B; Jenny, Hillary E; Saluja, Saurabh; Meara, John G; Shrime, Mark G; Alonso, Nivaldo

2016-10-01

Cleft lip and/or palate (CLP) is estimated to occur in 1 out of every 700 births, but for many people residing in low- and middle-income countries this deformity may be repaired late in life or not at all. This study aims to analyze worldwide provider-perceived barriers to the surgical repair of CLP in low- and middle-income countries. From 2011 to 2014, Smile Train distributed a multiple-choice, voluntary survey to healthcare providers to identify areas of need in CLP care worldwide. Data on provider-reported barriers to care were aggregated by year, country, and larger world regions. A total of 1997 surveys were completed by surgeons and healthcare providers (60.7% response rate). The most commonly reported barriers were "patient travel costs" (60.7%), "lack of patient awareness" (54.1%), and "lack of financial support" (52.8%). "Patient travel costs" was the most commonly reported barrier in sub-Saharan Africa, the Middle East and North Africa, and South and Southeast Asia. "Lack of financial support" was the most commonly reported barrier in the Americas, Eastern Europe, and East Asia. This is the largest intercontinental study on healthcare provider-identified barriers to care, representing the limitations experienced by healthcare professionals in providing corrective surgery for CLP around the world. Financial risk protection from hidden costs, such as patient travel costs, is essential. Community health workers and nurses are critical for communication and linking CLP care to the rest of the community. Recognition of these barriers can inform future policy decisions, targeted by region, for surgical systems delivering care for patients with CLP worldwide.

Changes in the biomechanical properties of a single cell induced by nonthermal atmospheric pressure micro-dielectric barrier discharge plasma.

Science.gov (United States)

Choi, Hyeongwon; Choi, Eun Ha; Kim, Kyung Sook

2017-10-01

Mechanical properties of a single cell are closely related to the fate and functions of the cell. Changes in mechanical properties may cause diseases or cell apoptosis. Selective cytotoxic effects of nonthermal atmospheric pressure micro-dielectric barrier discharge (DBD) plasma have been demonstrated on cancer cells. In this work, changes in the mechanical properties of a single cell induced by nonthermal atmospheric pressure micro-DBD plasma were investigated using atomic force microscopy (AFM). Two cervical cancer cell lines (HeLa and SiHa) and normal human fibroblast cells (HFBs) were exposed to micro-DBD plasma for various exposure times. The elasticity of a single cell was determined by force-distance curve measurement using AFM. Young's modulus was decreased by plasma treatment for all cells. The Young's modulus of plasma-treated HeLa cells was decreased by 75% compared to nontreated HeLa cells. In SiHa cells and HFBs, elasticity was decreased slightly. Chemical changes induced by the plasma treatment, which were observed by Raman spectroscopy, were also significant in HeLa cells compared to SiHa cells and HFBs. These results suggested that the molecular changes induced by micro-DBD plasma were related to cell mechanical changes. © 2017 Wiley Periodicals, Inc.

Analysis of Human Standing Balance by Largest Lyapunov Exponent

Directory of Open Access Journals (Sweden)

Kun Liu

2015-01-01

Full Text Available The purpose of this research is to analyse the relationship between nonlinear dynamic character and individuals’ standing balance by the largest Lyapunov exponent, which is regarded as a metric for assessing standing balance. According to previous study, the largest Lyapunov exponent from centre of pressure time series could not well quantify the human balance ability. In this research, two improvements were made. Firstly, an external stimulus was applied to feet in the form of continuous horizontal sinusoidal motion by a moving platform. Secondly, a multiaccelerometer subsystem was adopted. Twenty healthy volunteers participated in this experiment. A new metric, coordinated largest Lyapunov exponent was proposed, which reflected the relationship of body segments by integrating multidimensional largest Lyapunov exponent values. By using this metric in actual standing performance under sinusoidal stimulus, an obvious relationship between the new metric and the actual balance ability was found in the majority of the subjects. These results show that the sinusoidal stimulus can make human balance characteristics more obvious, which is beneficial to assess balance, and balance is determined by the ability of coordinating all body segments.

Healthcare barriers of refugees post-resettlement.

Science.gov (United States)

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

2009-12-01

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

Binding of higher alcohols onto Mn(12) single-molecule magnets (SMMs): access to the highest barrier Mn(12) SMM.

Science.gov (United States)

Lampropoulos, Christos; Redler, Gage; Data, Saiti; Abboud, Khalil A; Hill, Stephen; Christou, George

2010-02-15

Two new members of the Mn(12) family of single-molecule magnets (SMMs), [Mn(12)O(12)(O(2)CCH(2)Bu(t))(16)(Bu(t)OH)(H(2)O)(3)].2Bu(t)OH (3.2Bu(t)OH) and [Mn(12)O(12)(O(2)CCH(2)Bu(t))(16)(C(5)H(11)OH)(4)] (4) (C(5)H(11)OH is 1-pentanol), are reported. They were synthesized from [Mn(12)O(12)(O(2)CMe)(16)(H(2)O)(4)].2MeCO(2)H.4H(2)O (1) by carboxylate substitution and crystallization from the appropriate alcohol-containing solvent. Complexes 3 and 4 are new members of the recently established [Mn(12)O(12)(O(2)CCH(2)Bu(t))(16)(solv)(4)] (solv = H(2)O, alcohols) family of SMMs. Only one bulky Bu(t)OH can be accommodated into 3, and even this causes significant distortion of the [Mn(12)O(12)] core. Variable-temperature, solid-state alternating current (AC) magnetization studies were carried out on complexes 3 and 4, and they established that both possess an S = 10 ground state spin and are SMMs. However, the magnetic behavior of the two compounds was found to be significantly different, with 4 showing out-of-phase AC peaks at higher temperatures than 3. High-frequency electron paramagnetic resonance (HFEPR) studies were carried out on single crystals of 3.2Bu(t)OH and 4, and these revealed that the axial zero-field splitting constant, D, is very different for the two compounds. Furthermore, it was established that 4 is the Mn(12) SMM with the highest kinetic barrier (U(eff)) to date. The results reveal alcohol substitution as an additional and convenient means to affect the magnetization relaxation barrier of the Mn(12) SMMs without major change to the ligation or oxidation state.

InGaP Heterojunction Barrier Solar Cells

Science.gov (United States)

Welser, Roger E. (Inventor)

2014-01-01

A new solar cell structure called a heterojunction barrier solar cell is described. As with previously reported quantum-well and quantum-dot solar cell structures, a layer of narrow band-gap material, such as GaAs or indium-rich InGaP, is inserted into the depletion region of a wide band-gap PN junction. Rather than being thin, however, the layer of narrow band-gap material is about 400-430 nm wide and forms a single, ultrawide well in the depletion region. Thin (e.g., 20-50 nm), wide band-gap InGaP barrier layers in the depletion region reduce the diode dark current. Engineering the electric field and barrier profile of the absorber layer, barrier layer, and p-type layer of the PN junction maximizes photogenerated carrier escape. This new twist on nanostructured solar cell design allows the separate optimization of current and voltage to maximize conversion efficiency.

Fusion barrier distributions - What have we learned?

International Nuclear Information System (INIS)

Hinde, D. J.; Dasgupta, M.

1998-01-01

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

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.

Identifiability of location and magnitude of flow barriers in slightly compressible flow

NARCIS (Netherlands)

Kahrobaei, S.; Mansoori Habib Abadi, M.; Joosten, G.J.P.; Hof, Van den P.M.J.; Jansen, J.D.

2015-01-01

Classic identifiability analysis of flow barriers in incompressible single-phase flow reveals that it is not possible to identify the location and permeability of low-permeability barriers from production data (wellbore pressures and rates), and that only averaged reservoir properties in between

Identifiability of location and magnitude of flow barriers in slightly compressible flow

NARCIS (Netherlands)

Kahrobaei, S.; Mansoori Habib Abadi, M.; Joosten, G.J.P.; Van den Hof, P.; Jansen, J.D.

2016-01-01

Classic identifiability analysis of flow barriers in incompressible single-phase flow reveals that it is not possible to identify the location and permeability of low-permeability barriers from production data (wellbore pressures and rates), and that only averaged reservoir properties in between

Automated Impedance Tomography for Monitoring Permeable Reactive Barrier Health

Energy Technology Data Exchange (ETDEWEB)

LaBrecque, D J; Adkins, P L

2009-07-02

Kansas City barrier and the East Helena barrier. As these sites are also used for our field monitoring efforts, this allowed for a comparison between field and laboratory. In column studies with high concentrations of calcium and carbonate/bicarbonate, we observed that the increase of electrical resistivity and decrease of polarization magnitude is significant and is mainly controlled by the precipitation of calcium carbonates. In general, the electrical properties of all of the barriers studied follow a pattern. New barriers are fairly resistive with in-situ conductivity only a few times background (outside the barrier) values. Older barriers get increasingly conductive, with failed barriers showing values of over 100 S/m. The induced polarization response is more complicated. Chargeability values increase over time for young barriers, are largest for healthy barriers in the middle of their lifespan, and decrease as the barrier ages These results suggest that normalized IP appears promising as a measure of barrier age.

Ballistic transport through graphene nanostructures of velocity and potential barriers

International Nuclear Information System (INIS)

Krstajic, P M; Vasilopoulos, P

2011-01-01

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

On the compatibility of single crystal superalloys with a thermal barrier coating system

Energy Technology Data Exchange (ETDEWEB)

Wu, R.T. [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2BP (United Kingdom); Reed, R.C. [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2BP (United Kingdom)], E-mail: r.reed@birmingham.ac.uk

2008-02-15

The compatibility of three Co-containing prototype single crystal nickel-based superalloys with a thermal barrier coating (TBC) system is examined. These contain 2.1, 8.4 and 12.6 at.% Co; the concentrations of Al, Cr, Ta, W, Re, Hf are identical and chosen to be representative of advanced grades of these alloys. The TBC consists of an yttria-stabilized zirconia (YSZ) layer formed by electron beam physical vapour deposition (EB-PVD) and a bond coat made by electrodeposited platinum with a subsequent interdiffusion heat treatment - a so-called 'platinum-diffused' bond coat. The resistance to spallation of the TBC system is degraded as the Co content of the substrate increases. Wavelength-dispersive X-ray analysis and secondary ion mass spectrometry indicate that quantities of Co are present in the thermally grown oxide (TGO) by the time that failure occurs, this effect being most pronounced when the Co content of the substrate is high; the TGO is then more wavy and convoluted. The bond coat consists exclusively of the {gamma} and {gamma}' phases, with the balance shifting towards {gamma} with increasing thermal exposure; the loss of Al from the bond coat due to TGO formation means that the TGO is eventually in contact with the {gamma} phase solely, which is enriched in Co.

Environmental barriers, person-environment fit and mortality among community-dwelling very old people.

Science.gov (United States)

Rantakokko, Merja; Törmäkangas, Timo; Rantanen, Taina; Haak, Maria; Iwarsson, Susanne

2013-08-28

Environmental barriers are associated with disability-related outcomes in older people but little is known of the effect of environmental barriers on mortality. The aim of this study was to examine whether objectively measured barriers in the outdoor, entrance and indoor environments are associated with mortality among community-dwelling 80- to 89-year-old single-living people. This longitudinal study is based on a sample of 397 people who were single-living in ordinary housing in Sweden. Participants were interviewed during 2002-2003, and 393 were followed up for mortality until May 15, 2012.Environmental barriers and functional limitations were assessed with the Housing Enabler instrument, which is intended for objective assessments of Person-Environment (P-E) fit problems in housing and the immediate outdoor environment. Mortality data were gathered from the public national register. Cox regression models were used for the analyses. A total of 264 (67%) participants died during follow-up. Functional limitations increased mortality risk. Among the specific environmental barriers that generate the most P-E fit problems, lack of handrails in stairs at entrances was associated with the highest mortality risk (adjusted RR 1.55, 95% CI 1.14-2.10), whereas the total number of environmental barriers at entrances and outdoors was not associated with mortality. A higher number of environmental barriers indoors showed a slight protective effect against mortality even after adjustment for functional limitations (RR 0.98, 95% CI 0.96-1.00). Specific environmental problems may increase mortality risk among very-old single-living people. However, the association may be confounded by individuals' health status which is difficult to fully control for. Further studies are called for.

broken magnet highlights largest collider's engineering challenges

CERN Multimedia

Inman, Mason

2007-01-01

"Even at the world's soon-to-be largest particle accelerator - a device that promises to push the boundaries of physics - scientists need to be mindful of one of the most fundamental laws in the universe: Murphy's Law. (2 pages)

Search for Spin Filtering By Electron Tunneling Through Ferromagnetic EuS Barriers in Pbs

Science.gov (United States)

Figielski, T.; Morawski, A.; Wosinski, T.; Wrotek, S.; Makosa, A.; Lusakowska, E.; Story, T.; Sipatov, A. Yu.; Szczerbakow, A.; Grasza, K.;

Change of the work function and potential barrier transparency of W(100) and GaAs(110) single crystals during removing the inherent surface oxide layer

International Nuclear Information System (INIS)

Asalkhanov, Yu.I.; Saneev, Eh.L.

2002-01-01

Changes of current voltage characteristics of slow monoenergetic electron beam through the surfaces of W(100) and GaAs(100) single crystals have been measured in the process of surface oxide layers elimination. It is shown that work function is decreased and transparency coefficient of surface potential barrier is increased under increasing the temperature of vacuum annealing. Peculiarities of surface potential change under oxide layer elimination in metals and semiconductors are discussed [ru

On the pulsating electric wind of a Single Dielectric Barrier Discharge (SDBD) plasma actuator

Science.gov (United States)

Vernet, Julie; Örlü, Ramis; Alfredsson, P. Henrik

2014-11-01

An experimental study is conducted on the electric wind produced by a Single Dielectric Barrier Discharge (SDBD) plasma actuator placed at the top of a half cylinder. Laser Doppler Velocimetry (LDV) measurements were performed and results show that increasing the driving voltage (6-16 kV peak-to-peak) and frequency (0.5-2 kHz) of the actuator increases the induced jet velocity (up to 4 m/s) and thus the momentum added by the actuator. The focus of the present study is on the phase-resolved behavior of the electric wind, in particular, its two strokes. Phase-averaged LDV data reveals that while the velocity during both strokes remains positive, there is nearly a factor of two in amplitude. The difference of behavior between the two strokes and its downstream and wall-normal evolution are mapped for various driving voltages. Results indicate that this difference is restricted to the vicinity of the actuator, thereby justifying the assumption of a steady force in simulations to model the induced force. The study is part of a larger investigation aiming at separation control on the A-pillar of a truck cabin. The support of the Swedish Energy Agency and SCANIA CV of the project Flow Research on Active and Novel Control Efficiency (FRANCE) is greatly acknowledged.

Barriers to implementing the World Health Organization's Trauma Care Checklist: A Canadian single-center experience.

Science.gov (United States)

Nolan, Brodie; Zakirova, Rimma; Bridge, Jennifer; Nathens, Avery B

2014-11-01

Management of trauma patients is difficult because of their complexity and acuity. In an effort to improve patient care and reduce morbidity and mortality, the World Health Organization developed a trauma care checklist. Local stakeholder input led to a modified 16-item version that was subsequently piloted. Our study highlights the barriers and challenges associated with implementing this checklist at our hospital. The checklist was piloted over a 6-month period at St. Michael's Hospital, a Level 1 trauma center in Toronto, Canada. At the end of the pilot phase, individual, semistructured interviews were held with trauma team leaders and nursing staff regarding their experiences with the checklist. Axial coding was used to create a typology of attitudes and barriers toward the checklist, and then, vertical coding was used to further explore each identified barrier. Checklist compliance was assessed for the first 7 months. Checklist compliance throughout the pilot phase was 78%. Eight key barriers to implementing the checklist were identified as follows: perceived lack of time for the use of the checklist in critically ill patients, unclear roles, no memory trigger, no one to enforce completion, not understanding its importance or purpose, difficulty finding physicians at the end of resuscitation, staff/trainee changes, and professional hierarchy. The World Health Organization Trauma Care Checklist was a well-received tool; however, consideration of barriers to the implementation and staff adoption must be done for successful integration, with special attention to its use in critically ill patients. Therapeutic/care management, level V.

Corrosion of barrier materials in seawater environments

International Nuclear Information System (INIS)

Heiser, J.H.; Soo, P.

1995-07-01

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

Joint Asymptotic Distributions of Smallest and Largest Insurance Claims

Directory of Open Access Journals (Sweden)

Hansjörg Albrecher

2014-07-01

Full Text Available Assume that claims in a portfolio of insurance contracts are described by independent and identically distributed random variables with regularly varying tails and occur according to a near mixed Poisson process. We provide a collection of results pertaining to the joint asymptotic Laplace transforms of the normalised sums of the smallest and largest claims, when the length of the considered time interval tends to infinity. The results crucially depend on the value of the tail index of the claim distribution, as well as on the number of largest claims under consideration.

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

Application of diffusion barriers to high modulus fibers

Science.gov (United States)

Veltri, R. D.; Douglas, F. C.; Paradis, E. L.; Galasso, F. S.

1977-01-01

Barrier layers were coated onto high-modulus fibers, and nickel and titanium layers were overcoated as simulated matrix materials. The objective was to coat the high-strength fibers with unreactive selected materials without degrading the fibers. The fibers were tungsten, niobium, and single-crystal sapphire, while the materials used as barrier coating layers were Al2O3, Y2O3, TiC, ZrC, WC with 14% Co, and HfO2. An ion-plating technique was used to coat the fibers. The fibers were subjected to high-temperature heat treatments to evaluate the effectiveness of the barrier layer in preventing fiber-metal interactions. Results indicate that Al2O3, Y2O3, and HfO2 can be used as barrier layers to minimize the nickel-tungsten interaction. Further investigation, including thermal cycling tests at 1090 C, revealed that HfO2 is probably the best of the three.

Health Care Experiences and Perceived Barriers to Health Care Access: A Qualitative Study Among African Migrants in Guangzhou, Guangdong Province, China.

Science.gov (United States)

Lin, Lavinia; Brown, Katherine B; Yu, Fan; Yang, Jingqi; Wang, Jason; Schrock, Joshua M; Bodomo, Adams B; Yang, Ligang; Yang, Bin; Nehl, Eric J; Tucker, Joseph D; Wong, Frank Y

2015-10-01

Guangzhou, one of China's largest cities and a main trading port in South China, has attracted many African businessmen and traders migrating to the city for financial gains. Previous research has explored the cultural and economic roles of this newly emerging population; however, little is known about their health care experiences while in China. Semi-structured interviews and focus groups were used to assess health care experiences and perceived barriers to health care access among African migrants in Guangzhou, China. Overall, African migrants experienced various barriers to accessing health care and were dissatisfied with local health services. The principal barriers to care reported included affordability, legal issues, language barriers, and cultural differences. Facing multiple barriers, African migrants have limited access to care in Guangzhou. Local health settings are not accustomed to the African migrant population, suggesting that providing linguistically and culturally appropriate services may improve access to care for the migrants.

Barriers to preemptive renal transplantation: a single center questionnaire study.

Science.gov (United States)

Knight, Richard J; Teeter, Larry D; Graviss, Edward A; Patel, Samir J; DeVos, Jennifer M; Moore, Linda W; Gaber, A Osama

2015-03-01

Preemptive transplantation results in excellent patient and graft survival yet most transplant candidates are referred for transplantation after initiation of dialysis. The goal of this study was to determine barriers to preemptive renal transplantation. A nonvalidated questionnaire was administered to prospective kidney transplant recipients to determine factors that hindered or favored referral for transplantation before the initiation of dialysis. One hundred ninety-seven subjects referred for a primary renal transplant completed the questionnaire. Ninety-one subjects (46%) had been informed of preemptive transplantation before referral, and 80 (41%) were predialysis at the time of evaluation. The median time from diagnosis of renal disease to referral was 60 months (range, 2-444 months). In bivariate analysis, among other factors, knowledge of preemptive transplantation was highly associated (odds ratio=94.69) with referral before initiation of dialysis. Given the strong association between knowledge of preemptive transplantation and predialysis referral, this variable was not included in the multivariate analysis. Using multivariate logistic regression analysis, white recipient race, referral by a transplant nephrologist, recipient employment, and the diagnosis of polycystic kidney disease were significantly associated with presentation to the pretransplant clinic before initiation of dialysis. The principle barrier to renal transplantation referral before dialysis was patient education regarding the option of preemptive transplantation. Factors significantly associated with referral before dialysis were the diagnosis of polycystic kidney disease, white recipient race, referral by a transplant nephrologist, and employed status. Greater effort should be applied to patient education regarding preemptive transplantation early after the diagnosis of end-stage renal disease.

Memory-induced acceleration and slowdown of barrier crossing

Science.gov (United States)

Kappler, Julian; Daldrop, Jan O.; Brünig, Florian N.; Boehle, Moritz D.; Netz, Roland R.

2018-01-01

We study the mean first-passage time τMFP for the barrier crossing of a single massive particle with non-Markovian memory by Langevin simulations in one dimension. In the Markovian limit of short memory time τΓ, the expected Kramers turnover between the overdamped (high-friction) and the inertial (low-friction) limits is recovered. Compared to the Markovian case, we find barrier crossing to be accelerated for intermediate memory time, while for long memory time, barrier crossing is slowed down and τMFP increases with τΓ as a power law τM F P˜τΓ2. Both effects are derived from an asymptotic propagator analysis: while barrier crossing acceleration at intermediate memory can be understood as an effective particle mass reduction, slowing down for long memory is caused by the slow kinetics of energy diffusion. A simple and globally accurate heuristic formula for τMFP in terms of all relevant time scales of the system is presented and used to establish a scaling diagram featuring the Markovian overdamped and the Markovian inertial regimes, as well as the non-Markovian intermediate memory time regime where barrier crossing is accelerated and the non-Markovian long memory time regime where barrier crossing is slowed down.

Measuring effectiveness of three postfire hillslope erosion barrier treatments, western Montana, USA

Science.gov (United States)

Peter R. Robichaud; Frederick B. Pierson; Robert E. Brown; Joseph W. Wagenbrenner

2008-01-01

After the Valley Complex Fire burned 86 000 ha in western Montana in 2000, two studies were conducted to determine the effectiveness of contour-felled log, straw wattle, and hand-dug contour trench erosion barriers in mitigating postfire runoff and erosion. Sixteen plots were located across a steep, severely burned slope, with a single barrier installed in 12 plots (...

Scattering and pair production by a potential barrier

International Nuclear Information System (INIS)

Nikishov, A.I.

2004-01-01

Scattering and electron-positron pair production by a one-dimensional electric barrier is considered in the framework of the S-matrix formalism. The solution of the Dirac equation are classified according to frequency sign. The Bogolyubov transformations relating the in- and out-states are given. It is shown that the norm of a solution of the wave equation is determined by the largest amplitude of its asymptotic form when x 3 → ±∞. For the Sauter-type potential we give the explicit expressions for the complete in- and out-sets of orthonormalized wave functions. It is noted that in principle virtual vacuum processes in external field influence the phase of the wave function of the scattered particle [ru

Guaranteeing uptime at worl's largest particle physics lab

CERN Multimedia

Brodkin, Jon

2007-01-01

"As the European agency CERN was gearing up to build the world's largest particle accelerator, officials there knew they could not afford to have problems in their technical infrastructure cause any downtime." (1 page)

Single-Band and Dual-Band Infrared Detectors

Science.gov (United States)

Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor); Soibel, Alexander (Inventor); Nguyen, Jean (Inventor); Khoshakhlagh, Arezou (Inventor)

2017-01-01

Bias-switchable dual-band infrared detectors and methods of manufacturing such detectors are provided. The infrared detectors are based on a back-to-back heterojunction diode design, where the detector structure consists of, sequentially, a top contact layer, a unipolar hole barrier layer, an absorber layer, a unipolar electron barrier, a second absorber, a second unipolar hole barrier, and a bottom contact layer. In addition, by substantially reducing the width of one of the absorber layers, a single-band infrared detector can also be formed.

Efficacy of Tantalum Tungsten Alloys for Diffusion Barrier Applications

Science.gov (United States)

Smathers, D. B.; Aimone, P. R.

2017-12-01

Traditionally either Niobium, Tantalum or a combination of both have been used as diffusion barriers in Nb3Sn Multi-filament wire. Vanadium has also been used successfully but the ultimate RRR of the copper is limited unless an external shell of Niobium is included. Niobium is preferred over Tantalum when alternating current losses are not an issue as the Niobium will react to form Nb3Sn. Pure Tantalum tends to deform irregularly requiring extra starting thickness to ensure good barrier qualities. Our evaluations showed Tantalum lightly alloyed with 3 wt% Tungsten is compatible with the wire drawing process while deforming as well as or better than pure Niobium. Ta3wt%W has been processed as a single barrier and as a distributed barrier to fine dimensions. In addition, the higher modulus and strength of the Tantalum Tungsten alloy improves the overall tensile properties of the wire.

What hinder the further development of wind power in China?—A socio-technical barrier study

International Nuclear Information System (INIS)

Zhao, Zhen-Yu; Chang, Rui-Dong; Chen, Yu-Long

2016-01-01

Promoting wind power is a long-term strategy of China to respond to both energy shortage and environmental pollution. Stimulated by various incentive policies, wind power generation in China has achieved tremendous growth, with the cumulative installed capacity being the largest worldwide for five consecutive years since 2010. However, obstructed by various barriers, wind power provides only 2.6% of national electricity generation in China, despite the strong support from the government. From a socio-technical transition perspective, this paper aims to systematically analyze the barriers hindering the further development of China's wind power. A wind power niche model is established to illustrate the complex interactions among actors in the wind power industry and electricity supply regime. Then, qualitative content analysis is adopted to process the related evidence and data, and four categories of socio-technical barriers are identified, including technology, governance, infrastructure and culture barriers. The study shows that various interrelated barriers form a blocking mechanism which prohibits the further development of wind power in China. Policy suggestions are proposed to eliminate the barriers and further empower the wind power niche. The lesson learned from China can offer useful references for other economies to promote wind power industries of their own. - Highlights: • Use wind power niche model to illustrate the interactions among actors in the industry. • Analyze technological, governance, infrastructural and cultural barriers. • Multidimensionality and interconnectedness of the barriers are illustrated. • Policy suggestions are proposed to deal with the wind power development barriers.

The world's largest LNG producer's next market

International Nuclear Information System (INIS)

Fuller, R.; Isworo Suharno; Simandjuntak, W.M.P.

1996-01-01

The development of the domestic gas market in Indonesia, the world's largest liquefied natural gas producing country, is described as part of the overall impact of the country's oil and gas production. The first large scale use of natural gas in Indonesia was established in 1968 when a fertiliser plant using gas as the feedstock was built. Ultimately, through increased yields, this has enabled Indonesia to be self-sufficient in rice and an exporter of fertiliser. Problems which stand in the way of further developments include: capital, though Pertamina and PGN are perceived as attractive for foreign investment; the lack of a regulatory framework for gas; geographical constraints, among them the fact that the gas deposits are remote from the largest population concentrations; lack of infrastructure. There are nevertheless plans for expansion and the provision of an integrated gas pipeline system. Pertamina, which has responsibility for all oil and gas developments, and PGN, whose primary role has been as a manufacturer and distributor of gas, are now working together in the coordination of all gas activities. (10 figures). (UK)

Tank Farm Interim Surface Barrier Materials And Runoff Alternatives Study

International Nuclear Information System (INIS)

Holm, M.J.

2009-01-01

This report identifies candidate materials and concepts for interim surface barriers in the single-shell tank farms. An analysis of these materials for application to the TY tank farm is also provided.

Quasibound states in graphene quantum-dot nanostructures generated by concentric potential barrier rings

International Nuclear Information System (INIS)

Jiang Zhao-Tan; Yu Cheng-Long; Dong Quan-Li

2012-01-01

We study the quasibound states in a graphene quantum-dot structure generated by the single-, double-, and triple-barrier electrostatic potentials. It is shown that the strongest quasibound states are mainly determined by the innermost barrier. Specifically, the positions of the quasibound states are determined by the barrier height, the number of the quasibound states is determined by the quantum-dot radius and the angular momentum, and the localization degree of the quasibound states is influenced by the width of the innermost barrier, as well as the outside barriers. Furthermore, according to the study on the double- and triple-barrier quantum dots, we find that an effective way to generate more quasibound states with even larger energy level spacings is to design a quantum dot defined by many concentric barriers with larger barrier-height differences. Last, we extend our results into the quantum dot of many barriers, which gives a complete picture about the formation of the quasibound states in the kind of graphene quantum dot created by many concentric potential barrier rings. (rapid communication)

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)

Worlds Largest Wave Energy Project 2007 in Wales

DEFF Research Database (Denmark)

Christensen, Lars; Friis-Madsen, Erik; Kofoed, Jens Peter

2006-01-01

This paper introduces world largest wave energy project being developed in Wales and based on one of the leading wave energy technologies. The background for the development of wave energy, the total resource ands its distribution around the world is described. In contrast to wind energy turbines...... Dragon has to be scaled in accordance with the wave climate at the deployment site, which makes the Welch demonstrator device the worlds largest WEC so far with a total width of 300 meters. The project budget, the construction methods and the deployment site are also given....... a large number of fundamentally different technologies are utilised to harvest wave energy. The Wave Dragon belongs to the wave overtopping class of converters and the paper describes the fundamentals and the technical solutions used in this wave energy converter. An offshore floating WEC like the Wave...

First Experience from the World Largest fully commercial Solar Heating Plant

DEFF Research Database (Denmark)

Heller, Alfred; Furbo, Simon

1997-01-01

The first experience from the largest solar heating plant in the world is given. The plant is situated in Marstal and is has a total area of 8000 square m.......The first experience from the largest solar heating plant in the world is given. The plant is situated in Marstal and is has a total area of 8000 square m....

Fifteen Years of Operation at NASA's National Transonic Facility with the World's Largest Adjustable Speed Drive

Science.gov (United States)

Sydnor, George H.; Bhatia, Ram; Krattiger, Hansueli; Mylius, Justus; Schafer, D.

2012-01-01

In September 1995, a project was initiated to replace the existing drive line at NASA's most unique transonic wind tunnel, the National Transonic Facility (NTF), with a single 101 MW synchronous motor driven by a Load Commutated Inverter (LCI). This Adjustable Speed Drive (ASD) system also included a custom four-winding transformer, harmonic filter, exciter, switch gear, control system, and feeder cable. The complete system requirements and design details have previously been presented and published [1], as well as the commissioning and acceptance test results [2]. The NTF was returned to service in December 1997 with the new drive system powering the fan. Today, this installation still represents the world s largest horizontal single motor/drive combination. This paper describes some significant events that occurred with the drive system during the first 15 years of service. These noteworthy issues are analyzed and root causes presented. Improvements that have substantially increased the long term viability of the system are given.

Market Opportunities and Barriers for Smart Buildings

DEFF Research Database (Denmark)

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

2016-01-01

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

Challenges with the largest commercial hydrogen station in the world

Energy Technology Data Exchange (ETDEWEB)

Charbonneau, Thomas; Gauthier, Pierre [Air Liquide Canada (Canada)

2010-07-01

This abstract's objective is to share with the participants the story of the largest hydrogen fueling station made to this date and to kick-start the story, we will cover the challenges; first the technical ones; the operational ones; the distribution ones and; the financial ones. We will then move on to review the logistic (geographic) issues raised by the project and conclude our presentation by sharing the output values of the largest fueling station built so far in the world. (orig.)

Diabatic shifts and fluctuations of heavy-ion fusion barriers

International Nuclear Information System (INIS)

Berdichevsky, D.; Lukasiak, A.; Noerenberg, W.; Rozmej, P.

1988-01-01

The fusion process for heavy nuclei is studied within a generalized formulation of the diabatic approach to collective nuclear motion. It is shown that the coupled equations of motion decouple during the approach if appropriate diabatic channels are used. Thus the mean value and the variance of the barrier are completely determined from an ensemble of diabatic channel barriers, the ensemble being defined by the initial correlations. The mean shift with respect to the adiabatic barrier and the variance are calculated from the splitting of the diabatic single-particle levels at the barrier and the initial occupation probabilities given by the pairing wavefunctions of the separated nuclei. Results are presented for 23 systems of nuclei with masses around 100. Comparison with experimental data shows good agreement, in particular also for the isotopic trends. Additional effects from the destruction of pairing correlations and the diabatic screening of the fusion pocket for heavier nuclei with Z 1 Z 2 > or approx. 2000 are discussed. (orig.)

A multicentre, randomised, controlled trial to assess the safety, ease of use, and reliability of hyaluronic acid/carboxymethylcellulose powder adhesion barrier versus no barrier in colorectal laparoscopic surgery.

Science.gov (United States)

Berdah, Stéphane V; Mariette, Christophe; Denet, Christine; Panis, Yves; Laurent, Christophe; Cotte, Eddy; Huten, Nöel; Le Peillet Feuillet, Eliane; Duron, Jean-Jacques

2014-10-27

Intra-peritoneal adhesions are frequent following abdominal surgery and are the most common cause of small bowel obstructions. A hyaluronic acid/carboxymethylcellulose (HA/CMC) film adhesion barrier has been shown to reduce adhesion formation in abdominal surgery. An HA/CMC powder formulation was developed for application during laparoscopic procedures. This was an exploratory, prospective, randomised, single-blind, parallel-group, Phase IIIb, multicentre study conducted at 15 hospitals in France to assess the safety of HA/CMC powder versus no adhesion barrier following laparoscopic colorectal surgery. Subjects ≥18 years of age who were scheduled for colorectal laparoscopy (Mangram contamination class I‒III) within 8 weeks of selection were eligible, regardless of aetiology. Participants were randomised 1:1 to the HA/CMC powder or no adhesion barrier group using a centralised randomisation list. Patients assigned to HA/CMC powder received a single application of 1 to 10 g on adhesion-prone areas. In the no adhesion barrier group, no adhesion barrier or placebo was applied. The primary safety assessments were the incidence of adverse events, serious adverse events, and surgical site infections (SSIs) for 30 days following surgery. Between-group comparisons were made using Fisher's exact test. Of those randomised to the HA/CMC powder (n = 105) or no adhesion barrier (n = 104) groups, one patient in each group discontinued prior to the study end (one death in each group). Adverse events were more frequent in the HA/CMC powder group versus the no adhesion barrier group (63% vs. 39%; P barrier group in SSIs (21% vs. 14%; P = 0.216) and serious SSIs (12% vs. 9%; P = 0.38), or in the most frequent serious SSIs of pelvic abscess (5% and 2%; significance not tested), anastomotic fistula (3% and 4%), and peritonitis (2% and 3%). This exploratory study found significantly higher rates of adverse events and serious adverse events in the HA/CMC powder group compared with

Effect of nanodimensional polyethylenimine layer on surface potential barriers of hybrid structures based on silicon single crystal

Science.gov (United States)

Malyar, Ivan V.; Gorin, Dmitry A.; Stetsyura, Svetlana V.

2013-01-01

In this report we present the analysis of I-V curves for MIS-structures like silicon substrate / nanodimensional polyelectrolyte layer / metal probe (contact) which is promising for biosensors, microfluidic chips, different devices of molecular electronics, such as OLEDs, solar cells, where polyelectrolyte layers can be used to modify semiconductor surface. The research is directed to investigate the contact phenomena which influence the resulting signal of devices mentioned above. The comparison of I-V characteristics of such structures measured by scanning tunnel microscopy (contactless technique) and using contact areas deposited by thermal evaporation onto the organic layer (the contact one) was carried out. The photoassisted I-V measurements and complex analysis based on Simmons and Schottky models allow one to extract the potential barriers and to observe the changes of charge transport in MIS-structures under illumination and after polyelectrolyte adsorption. The direct correlation between the thickness of the deposited polyelectrolyte layer and both equilibrium tunnel barrier and Schottky barrier height was observed for hybrid structures with polyethylenimine. The possibility of control over the I-V curves of hybrid structure and the height of the potential barriers (for different charge transports) by illumination was confirmed. Based on experimental data and complex analysis the band diagrams were plotted which illustrate the changes of potential barriers for MIS-structures due to the polyelectrolyte adsorption and under the illumination.

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.

Building Earth's Largest Library: Driving into the Future.

Science.gov (United States)

Coffman, Steve

1999-01-01

Examines the Amazon.com online bookstore as a blueprint for designing the world's largest library. Topics include selection; accessibility and convenience; quality of Web sites and search tools; personalized service; library collection development, including interlibrary loan; library catalogs and catalog records; a circulation system; costs;…

Toward sustainable harvesting of Africa's largest medicinal plant ...

African Journals Online (AJOL)

Global demand for treating prostate disorders with Prunus africana bark extract has made P. africana Africa's largest medicinal plant export. Unsustainable harvesting practices can lead to local extirpations of this multipurpose tree. Survey research targeting P. africana harvesters in a Tanzania forest reserve revealed that ...

Investigation of the geometrical barrier in Bi-2212 using the magneto-optical technique

International Nuclear Information System (INIS)

Lin, Z.W.

2000-01-01

It has been found that the penetration of vortices into a weak pinning crystal is governed by a geometrical barrier and they form a dome-shaped flux profile across the crystal. Using the powerful magneto-optical technique, we investigated this geometrical barrier in a high-purity Bi 2 Sr 2 CaCu 2 O 8+x single-crystal platelet. Our results show that over the temperature range 20-70 K the dome-shaped profile is observed. Also, the influences of the edge shape and the roughness on the geometrical barrier are discussed. (author)

Qualitative risk assessment of subsurface barriers in applications supporting retrieval of SST waste

International Nuclear Information System (INIS)

Treat, R.L.

1994-04-01

This report provides a brief, qualitative assessment of risks associated with the potential use of impermeable surface barriers installed around and beneath Hanford Site single-shell tanks (SSTs) to support the retrieval of wastes from those tanks. These risks are compared to qualitative assessment of costs and risks associated with a case in which barriers are not used. A quantitative assessment of costs and risks associated with these two cases will be prepared and documented in a companion report. The companion report will compare quantitatively the costs and risks of several retrieval options with varying parameters, such as effectiveness of retrieval, effectiveness of subsurface barriers, and the use of surface barriers. For ease of comparison of qualitative risks, a case in which impermeable subsurface barriers are used in conjunction with another technology to remove tank waste is referred, to in this report as the Barrier Case. A case in which waste removal technologies are used without employing a subsurface barrier is referred to as the No Barrier Case. The technologies associated with each case are described in the following sections

Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium.

Science.gov (United States)

Smith, I M; Baker, A; Arneborg, N; Jespersen, L

2015-11-01

The human gastrointestinal epithelium makes up the largest barrier separating the body from the external environment. Whereas invasive pathogens cause epithelial barrier disruption, probiotic micro-organisms modulate tight junction regulation and improve epithelial barrier function. In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability of four nonpathogenic yeast species to modulate transepithelial electrical resistance (TER) across a monolayer of differentiated human colonocytes (Caco-2 cells). Further, we assessed yeast modulation of a Salmonella Typhimurium-induced epithelial cell barrier function insult. Our findings demonstrate distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study demonstrates distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Further, our data demonstrate significant yeast-mediated modulation of Salmonella Typhimurium-induced epithelial cell barrier disruption and identify Kluyveromyces marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study is the first to demonstrate significant non-Saccharomyces yeast

Low calcification in corals in the Great Barrier Reef

Science.gov (United States)

Bhattacharya, Atreyee

2012-10-01

Reef-building coral communities in the Great Barrier Reef—the world's largest coral reef—may now be calcifying at only about half the rate that they did during the 1970s, even though live coral cover may not have changed over the past 40 years, a new study finds. In recent decades, coral reefs around the world, home to large numbers of fish and other marine species, have been threatened by such human activities as pollution, overfishing, global warming, and ocean acidification; the latter affects ambient water chemistry and availability of calcium ions, which are critical for coral communities to calcify, build, and maintain reefs. Comparing data from reef surveys during the 1970s, 1980s, and 1990s with present-day (2009) measurements of calcification rates in One Tree Island, a coral reef covering 13 square kilometers in the southern part of the Great Barrier Reef, Silverman et al. show that the total calcification rates (the rate of calcification minus the rate of dissolution) in these coral communities have decreased by 44% over the past 40 years; the decrease appears to stem from a threefold reduction in calcification rates during nighttime.

State of offsite construction in India-Drivers and barriers

Science.gov (United States)

Arif, M.; Bendi, D.; Sawhney, A.; Iyer, K. C.

2012-05-01

The rapid growth of the construction industry in India has influenced key players in the industry to adopt alternative technologies addressing time, cost and quality. The rising demand in housing, infrastructure and other facilities have further highlighted the need for the construction industry to look at adopting alternate building technologies. Offsite construction has evolved as a panacea to dealing with the under-supply and poor quality in the current age construction industry. Several offsite techniques have been adopted by the construction sector. Although, different forms of offsite techniques have been around for a while but their uptake has been low in the Indian context. This paper presents the perceptions about offsite construction in India and highlights some of the barriers and drivers facing the Indian construction industry. The data was gathered through a survey of 17 high level managers from some of the largest stakeholder organizations of the construction sector in India. The influence of time and cost has been highlighted as a major factor fuelling the adoption of offsite construction. However, the influence of current planning systems and the need for a paradigm shift are some of the prominent barriers towards the adoption of offsite techniques.

Kabob report. Pt. 3. Chevron plant largest in Canada

Energy Technology Data Exchange (ETDEWEB)

1971-01-18

Canada's largest fully integrated primary natural- gas processing and sulfur recovery plant is heading for physical completion by mid-summer of 1971. The Ralph M. Parsons Construction Co. of Canada Ltd., contractor for the S. Kaybob Beaverhill Lake Unit No. 3 gas-processing plant, to be operated by Chevron Standard Ltd., estimates completion by June 30. After that the $80 million complex will have tests and running in time. With any reasonable luck, it should be fully on stream by late summer. Preliminary construction on the 200-acre site started in Jan. 1969 with clearing and contouring of the main plant and sulfur storage sites. Initial rough grading started in the early summer, after spring breakup was over. Delivery of most of the big items was made by rail because the local secondary roads were inadequate for them. Concrete has been a large item. The contractor has its own batch plant on the site for the estimated 28,000 cu yd which will be needed for the whole job. Dominating the construction site from the start has been the high sulfur plant stack, first of the major items to be finished. It will serve to dispose of effluent from the largest sulfur recovery unit in Canada. It is 465 ft high, one of the largest in Alberta, and a significant contribution to pollution control and environmental protection.

Bidirectional sorting of flocking particles in the presence of asymmetric barriers.

Science.gov (United States)

Drocco, Jeffrey A; Olson Reichhardt, C J; Reichhardt, C

2012-05-01

We demonstrate numerically bidirectional sorting of flocking particles interacting with an array of V-shaped asymmetric barriers. Each particle aligns with the average swimming direction of its neighbors according to the Vicsek model and experiences additional steric interactions as well as repulsion from the fixed barriers. We show that particles preferentially localize to one side of the barrier array over time and that the direction of this rectification can be reversed by adjusting the particle-particle exclusion radius or the noise term in the equations of motion. These results provide a conceptual basis for isolation and sorting of single-cell and multicellular organisms that move collectively according to flocking-type interaction rules.

Output voltage calculations in double barrier magnetic tunnel junctions with asymmetric voltage behavior

KAUST Repository

Useinov, Arthur

2011-10-22

In this paper we study the asymmetric voltage behavior (AVB) of the tunnel magnetoresistance (TMR) for single and double barrier magnetic tunnel junctions (MTJs) in range of a quasi-classical free electron model. Numerical calculations of the TMR-V curves, output voltages and I-V characteristics for negative and positive values of applied voltages were carried out using MTJs with CoFeB/MgO interfaces as an example. Asymmetry of the experimental TMR-V curves is explained by different values of the minority and majority Fermi wave vectors for the left and right sides of the tunnel barrier, which arises due to different annealing regimes. Electron tunneling in DMTJs was simulated in two ways: (i) Coherent tunneling, where the DMTJ is modeled as one tunnel system and (ii) consecutive tunneling, where the DMTJ is modeled by two single barrier junctions connected in series. © 2012 Elsevier B.V. All rights reserved.

Direct plasma NO_x reduction using single surface dielectric barrier discharge

DEFF Research Database (Denmark)

Kroushawi, Feisal; Stamate, Eugen

2014-01-01

NOx reduction using direct atmospheric barrier discharge in air-NO mixture at different voltages and flow rates is inversigated. Reduction rate of 80% is achieved at 3.18 W/cm2 power density and gas mixture of 20 slm air and 0.006 slm NO. The ozone for NO reduction is produced by a honeycomb stru...

Upgrade and modernization of the six largest HPPs in Macedonia

International Nuclear Information System (INIS)

Hadzievska, M.

2002-01-01

In 1998, Electric Power Company of Macedonia and the International Bank for Development and Reconstruction, started the Power System Improvement Project a part of which is the Project for rehabilitation of the six largest Hydro Power Plants (HPPs) in the Republic of Macedonia. The six largest Hydro Power Plants (HPP Vrutok, HPP Raven, HPP Globocica, HPP Tikves and HPP Spilje and HPP Vrben) represent 91% of the country's hydropower capacity. The rehabilitation program is divided in five parts (contracts) and covers the refurbishment of: turbine runners, turbine and generator bearings, governors, inlet valves; butterfly valves, including accessories and control systems; generators, excitation system and voltage regulation; control system, protection and LV auxiliaries; switch gears and control gears in 220 kV, 110 kV and 35 kV substations. At the moment, only the implementation of switch gears has started, the first phase is already finished, and 50 % of the rehabilitation works for HPP Vrutok, the largest HPP, has been finished. With the realization of this project, greater hydropower production is expected. It also expected that HPPs will become a more vital part of the Macedonian power system

Geochronologic evidence for a possible MIS-11 emergent barrier/beach-ridge in southeastern Georgia, USA

Science.gov (United States)

Markewich, H.W.; Pavich, M.J.; Schultz, A.P.; Mahan, S.A.; Aleman-Gonzalez, W. B.; Bierman, P.R.

2013-01-01

Predominantly clastic, off-lapping, transgressive, near-shore marine sediment packages that are morphologically expressed as subparallel NE-trending barriers, beach ridges, and associated back-barrier areas, characterize the near-surface stratigraphic section between the Savannah and the Ogeechee Rivers in Effingham County, southeastern Georgia. Each barrier/back-barrier (shoreline) complex is lower than and cut into a higher/older complex. Each barrier or shoreline complex overlies Miocene strata. No direct age data are available for these deposits. Previous researchers have disagreed on their age and provenance. Using luminescence and meteoric beryllium-10 (10Be) inventory analyses, we estimated a minimum age for the largest, westernmost, morphologically identifiable, and topographically-highest, barrier/beach-ridge (the Wicomico shoreline barrier) and constrained the age of a suite of younger barrier/beach-ridges that lie adjacent and seaward of the Wicomico shoreline barrier. At the study site, the near-shore marine/estuarine deposits underlying the Wicomico shoreline barrier are overlain by eolian sand and an intervening zone-of-mixing. Optically stimulated luminescence (OSL) data indicate ages of ≤43 ka for the eolian sand and 116 ka for the zone-of-mixing. Meteoric 10Be and pedostratigraphic data indicate minimum residence times of 33.4 ka for the eolian sand, 80.6 ka for the zone-of-mixing, and 247 ka for the paleosol. The combined OSL and 10Be age data indicate that, at this locality, the barrier/beach ridge has a minimum age of about 360 ka. This age for the Wicomico shoreline-barrier deposit is the first for any Pleistocene near-shore marine/estuarine deposit in southeast Georgia that is conclusively older than 80 ka. The 360-ka minimum age is in agreement with other geochronologic data for near-coastline deposits in Georgia and South Carolina. The geomorphic position of this barrier/beach-ridge is similar to deposits in South Carolina considered to be

How to manage barriers to formation and implementation of policy packages in transport

DEFF Research Database (Denmark)

Åkerman, Jonas; Gudmundsson, Henrik; Sørensen, Claus Hedegaard

2011-01-01

The aim of this study has been to explore success factors and barriers to the formation and implementation of single policy measures and policy packages in transport, and to identify strategies to manage such barriers. As a first step, we developed a typology of barriers and success factors...... for policy formation and implementation. Secondly, we carried out an empirical analysis of barriers and success factors in four cases of policy packaging: Urban Congestion Charging; National Heavy Vehicle Fees; Aviation in the European Emissions Trading System and The EU’s First Railway Package. The third...... and final task was to identify more general strategies to manage barriers in policy formation and implementation. A main conclusion in this report is that a conscious application of these strategies may contribute significantly to successful formation and implementation of even controversial policies...

Quantitative occupational risk model: Single hazard

International Nuclear Information System (INIS)

Papazoglou, I.A.; Aneziris, O.N.; Bellamy, L.J.; Ale, B.J.M.; Oh, J.

2017-01-01

A model for the quantification of occupational risk of a worker exposed to a single hazard is presented. The model connects the working conditions and worker behaviour to the probability of an accident resulting into one of three types of consequence: recoverable injury, permanent injury and death. Working conditions and safety barriers in place to reduce the likelihood of an accident are included. Logical connections are modelled through an influence diagram. Quantification of the model is based on two sources of information: a) number of accidents observed over a period of time and b) assessment of exposure data of activities and working conditions over the same period of time and the same working population. Effectiveness of risk reducing measures affecting the working conditions, worker behaviour and/or safety barriers can be quantified through the effect of these measures on occupational risk. - Highlights: • Quantification of occupational risk from a single hazard. • Influence diagram connects working conditions, worker behaviour and safety barriers. • Necessary data include the number of accidents and the total exposure of worker • Effectiveness of risk reducing measures is quantified through the impact on the risk • An example illustrates the methodology.

World's third-largest producer of nuclear power. Japan in need of energy

International Nuclear Information System (INIS)

Anon.

2008-01-01

Japan is the third largest oil consumer in the world behind the United States and China, and the second largest net importer of oil. Japan boasts one of the largest economies in the world. The country continues to experience a moderate economic recovery that began in 2003, following a decade of economic stagnation. Japan's real gross domestic product (GDP) grew by 2.5% in 2005 and 2.3% in 2004. The modest upturn over the last few years reflects higher business confidence in Japan, a surge in export demand led by exports to China, and robust consumer spending. Unemployment in Japan fell to 4.4% in 2005, down from an early 2003 peak of 5.5%. Japan has virtually no domestic oil or natural gas reserves, and in 2005 was the second largest net importer of crude oil in the world. Despite the country's dearth of hydrocarbon resources, Japanese companies have actively pursued upstream oil and natural gas projects overseas. Japan remains one of the major exporters of energy-sector capital equipment, and Japanese companies provide engineering, construction, and project management services for energy projects. (orig.)

TMX-U thermal-barrier experiments

International Nuclear Information System (INIS)

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

1988-01-01

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

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.

NAFTA: The World's Largest Trading Zone Turns 20

Science.gov (United States)

Ferrarini, Tawni Hunt; Day, Stephen

2014-01-01

Everyone under the age of 20 who has grown up in North America has lived in the common market created by NAFTA--the North American Free Trade Agreement. In a zone linking the United States, Canada, and Mexico, most goods and investments flow freely across borders to users, consumers, and investors. In 1994, NAFTA created the largest relatively…

The progression of replication forks at natural replication barriers in live bacteria.

Science.gov (United States)

Moolman, M Charl; Tiruvadi Krishnan, Sriram; Kerssemakers, Jacob W J; de Leeuw, Roy; Lorent, Vincent; Sherratt, David J; Dekker, Nynke H

2016-07-27

Protein-DNA complexes are one of the principal barriers the replisome encounters during replication. One such barrier is the Tus-ter complex, which is a direction dependent barrier for replication fork progression. The details concerning the dynamics of the replisome when encountering these Tus-ter barriers in the cell are poorly understood. By performing quantitative fluorescence microscopy with microfuidics, we investigate the effect on the replisome when encountering these barriers in live Escherichia coli cells. We make use of an E. coli variant that includes only an ectopic origin of replication that is positioned such that one of the two replisomes encounters a Tus-ter barrier before the other replisome. This enables us to single out the effect of encountering a Tus-ter roadblock on an individual replisome. We demonstrate that the replisome remains stably bound after encountering a Tus-ter complex from the non-permissive direction. Furthermore, the replisome is only transiently blocked, and continues replication beyond the barrier. Additionally, we demonstrate that these barriers affect sister chromosome segregation by visualizing specific chromosomal loci in the presence and absence of the Tus protein. These observations demonstrate the resilience of the replication fork to natural barriers and the sensitivity of chromosome alignment to fork progression. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Chaotic correlations in barrier billiards with arbitrary barriers

International Nuclear Information System (INIS)

Osbaldestin, A H; Adamson, L N C

2013-01-01

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

The Environmental Responsibility of the World’s Largest Banks

Directory of Open Access Journals (Sweden)

Ryszawska Bożena

2018-03-01

Full Text Available Sustainability transition is changing the role and function of banks, specially their products and services also in relation to stakeholders. Banks are one of the main actors supporting the transition to sustainable economy. The purpose of this study is to emphasise the role of world’s largest banks in that process. Banks are slowly responding to the new demand of sustainability and responsibility, and they try to align with it. The paper is based on an overview of the world’s five largest banks that employ corporate social responsibility (CSR reporting standards, together with detailed enumeration of pro-environmental activities included in the reports. The first section of this paper presents the most popular approaches to the problem at hand, as reported in professional literature. Section two presents the characteristics of the CSR actions in banks. The third section discusses the environmental actions of the biggest banks in Global Reporting Initiative (GRI reporting the most popular standard for reporting non-financial information. And the last part of the paper presents the conclusions resulting from the article. The research was conducted using a variety of sources, such as scientific articles, statistical data, CSR reports of the world’s largest banks, as well reporting principles and standard disclosures. The basic method used in the process of writing was a critical analysis of literature and reports concerning the CSR reporting standards, environmental responsibilities of different kinds of entities, as well as own observations based on special reports of banks. In the article, also the analysis of financial market data, induction method and comparison method have been used. The main conclusions of the analysis of the CSR reports disclosed by the world’s largest banks confirm all three of the theses presented in the article. The findings suggest that the banks under study can be regarded as environmentally responsible

Oceans of Opportunity. Harnessing Europe's largest domestic energy resource

International Nuclear Information System (INIS)

Fichaux, N.; Wilkes, J.

2009-09-01

Europe's offshore wind potential is enormous and able to power Europe seven times over. Over 100 GW of offshore wind projects are already in various stages of planning. If realised, these projects would produce 10% of the EU's electricity whilst avoiding 200 million tonnes of CO2 emissions each year. EWEA has a target of 40 GW of offshore wind in the EU by 2020, implying an average annual market growth of 28% over the coming 12 years. The EU market for onshore wind grew by an average 32% per year in the 12-year period from 1992-2004 - what the wind energy industry has achieved on land can be repeated at sea. EWEA's proposed offshore grid builds on the 11 offshore grids currently operating and 21 offshore grids currently being considered by the grid operators in the Baltic and North Seas to give Europe a truly pan-European electricity super highway. Strong political support and action from Europe's policy-makers will allow a new, multi-billion euro industry to be built. This new industry will deliver thousands of green collar jobs and a new renewable energy economy and establish Europe as world leader in offshore wind power technology. A single European electricity market with large amounts of wind power will bring affordable electricity to consumers, reduce import dependence, cut CO2 emissions and allow Europe to access its largest domestic energy source.

Smart parking barrier

KAUST Repository

Alharbi, Abdulrazaq M.

2016-01-01

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

γδ T cells in homeostasis and host defence of epithelial barrier tissues

DEFF Research Database (Denmark)

Nielsen, Morten M.; Witherden, Deborah A.; Havran, Wendy L.

2017-01-01

Epithelial surfaces line the body and provide a crucial interface between the body and the external environment. Tissue-resident epithelial γδ T cells represent a major T cell population in the epithelial tissues and are ideally positioned to carry out barrier surveillance and aid in tissue...... homeostasis and repair. In this Review, we focus on the intraepithelial γδ T cell compartment of the two largest epithelial tissues in the body — namely, the epidermis and the intestine — and provide a comprehensive overview of the crucial contributions of intraepithelial γδ T cells to tissue integrity...

Effect of a gap opening on the conductance of graphene with magnetic barrier structures

Science.gov (United States)

Esmailpour, Mohammad

2018-04-01

In the present study Klein tunneling in a single-layer gapped graphene was investigated by transfer matrix method under normal magnetic field for one and two magnetic barriers. Calculations show that electron transmission through a magnetic barrier is deflected to positive angles and reduces as the magnitude of magnetic field and especially the energy gap increases. This reduction is even more significant in larger fields so that after reaching a specific value of energy gap, an effective confinement for fermions and suppression of Klein tunneling is reached particularly in normal incidence and the conductance becomes zero. Unlike one barrier, the process of tunneling through two magnetic barriers induces symmetric transmission probability versus the incident angle; even, for lower energy gaps, electron transmission probability increases which in turn reduces total conductance via proper changes in the value of the magnetic field and energy gap. In general, it is concluded that confining electrons in asymmetric transmission through one barrier is conducted better than two barriers.

Asymmetric voltage behavior of the tunnel magnetoresistance in double barrier magnetic tunnel junctions

KAUST Repository

Useinov, Arthur

2012-06-01

In this paper, we study the value of the tunnel magnetoresistance (TMR) as a function of the applied voltage in double barrier magnetic tunnel junctions (DMTJs) with the left and right ferromagnetic (FM) layers being pinned and numerically estimate the possible difference of the TMR curves for negative and positive voltages in the homojunctions (equal barriers and electrodes). DMTJs are modeled as two single barrier junctions connected in series with consecutive tunneling (CST). We investigated the asymmetric voltage behavior of the TMR for the CST in the range of a general theoretical model. Significant asymmetries of the experimental curves, which arise due to different annealing regimes, are mostly explained by different heights of the tunnel barriers and asymmetries of spin polarizations in magnetic layers. © (2012) Trans Tech Publications.

Asymmetric voltage behavior of the tunnel magnetoresistance in double barrier magnetic tunnel junctions

KAUST Repository

Useinov, Arthur; Gooneratne, Chinthaka Pasan; Kosel, Jü rgen

2012-01-01

In this paper, we study the value of the tunnel magnetoresistance (TMR) as a function of the applied voltage in double barrier magnetic tunnel junctions (DMTJs) with the left and right ferromagnetic (FM) layers being pinned and numerically estimate the possible difference of the TMR curves for negative and positive voltages in the homojunctions (equal barriers and electrodes). DMTJs are modeled as two single barrier junctions connected in series with consecutive tunneling (CST). We investigated the asymmetric voltage behavior of the TMR for the CST in the range of a general theoretical model. Significant asymmetries of the experimental curves, which arise due to different annealing regimes, are mostly explained by different heights of the tunnel barriers and asymmetries of spin polarizations in magnetic layers. © (2012) Trans Tech Publications.

Statistics of the largest sunspot and facular areas per solar cycle

International Nuclear Information System (INIS)

Willis, D.M.; Kabasakal Tulunay, Y.

1979-01-01

The statistics of extreme values is used to investigate the statistical properties of the largest areas sunspots and photospheric faculae per solar cycle. The largest values of the synodic-solar-rotation mean areas of umbrae, whole spots and faculae, which have been recorded for nine solar cycles, are each shown to comply with the general form of the extreme value probability function. Empirical expressions are derived for the three extreme value populations from which the characteristic statistical parameters, namely the mode, median, mean and standard deviation, can be calculated for each population. These three extreme value populations are also used to find the expected ranges of the extreme areas in a group of solar cycles as a function of the number of cycles in the group. The extreme areas of umbrae and whole spots have a dispersion comparable to that found by Siscoe for the extreme values of sunspot number, whereas the extreme areas of faculae have a smaller dispersion which is comparable to that found by Siscoe for the largest geomagnetic storm per solar cycle. The expected range of the largest sunspot area per solar cycle for a group of one hundred cycles appears to be inconsistent with the existence of the prolonged periods of sunspot minima that have been inferred from the historical information on solar variability. This inconsistency supports the contention that there are temporal changes of solar-cycle statistics during protracted periods of sunspot minima (or maxima). Indeed, without such temporal changes, photospheric faculae should have been continually observable throughout the lifetime of the Sun. (orig.)

Fishing down the largest coral reef fish species.

Science.gov (United States)

Fenner, Douglas

2014-07-15

Studies on remote, uninhabited, near-pristine reefs have revealed surprisingly large populations of large reef fish. Locations such as the northwestern Hawaiian Islands, northern Marianas Islands, Line Islands, U.S. remote Pacific Islands, Cocos-Keeling Atoll and Chagos archipelago have much higher reef fish biomass than islands and reefs near people. Much of the high biomass of most remote reef fish communities lies in the largest species, such as sharks, bumphead parrots, giant trevally, and humphead wrasse. Some, such as sharks and giant trevally, are apex predators, but others such as bumphead parrots and humphead wrasse, are not. At many locations, decreases in large reef fish species have been attributed to fishing. Fishing is well known to remove the largest fish first, and a quantitative measure of vulnerability to fishing indicates that large reef fish species are much more vulnerable to fishing than small fish. The removal of large reef fish by fishing parallels the extinction of terrestrial megafauna by early humans. However large reef fish have great value for various ecological roles and for reef tourism. Copyright © 2014 Elsevier Ltd. All rights reserved.

Improved HEPA Filter Technology for Flexible and Rigid Containment Barriers

International Nuclear Information System (INIS)

Pinson, Paul Arthur

1998-01-01

Safety and reliability in glovebox operations can be significantly improved and waste packaging efficiencies can be increased by inserting flexible, lightweight, high capacity HEPA filters into the walls of plastic sheet barriers. This HEPA filter/barrier technology can be adapted to a wide variety of applications: disposable waste bags, protective environmental barriers for electronic equipment, single or multiple use glovebag assemblies, flexible glovebox wall elements, and room partitions. These reliable and inexpensive filtered barriers have many uses in fields such as radioactive waste processing, HVAC filter changeout, vapor or grit blasting, asbestos cleanup, pharmaceutical, medical, biological, and electronic equipment containment. The applications can result in significant cost savings, improved operational reliability and safety, and total waste volume reduction. This technology was developed at the Argonne National Laboratory-West (ANL-W) in 1993 and has been used at ANL-W since then at the TRU Waste Characterization Chamber Gloveboxes. Another 1998 AGS Conference paper titled ''TRU Waste Characterization Gloveboxes'', presented by Mr. David Duncan of ANL-W, describes these boxes

The Multivariate Largest Lyapunov Exponent as an Age-Related Metric of Quiet Standing Balance

Directory of Open Access Journals (Sweden)

Kun Liu

2015-01-01

Full Text Available The largest Lyapunov exponent has been researched as a metric of the balance ability during human quiet standing. However, the sensitivity and accuracy of this measurement method are not good enough for clinical use. The present research proposes a metric of the human body’s standing balance ability based on the multivariate largest Lyapunov exponent which can quantify the human standing balance. The dynamic multivariate time series of ankle, knee, and hip were measured by multiple electrical goniometers. Thirty-six normal people of different ages participated in the test. With acquired data, the multivariate largest Lyapunov exponent was calculated. Finally, the results of the proposed approach were analysed and compared with the traditional method, for which the largest Lyapunov exponent and power spectral density from the centre of pressure were also calculated. The following conclusions can be obtained. The multivariate largest Lyapunov exponent has a higher degree of differentiation in differentiating balance in eyes-closed conditions. The MLLE value reflects the overall coordination between multisegment movements. Individuals of different ages can be distinguished by their MLLE values. The standing stability of human is reduced with the increment of age.

Crash testing the largest experiment on Earth

OpenAIRE

Cauchi, Marija

2015-01-01

Under Europe lies a 27 km tunnel that is both the coldest and hottest place on Earth. The Large Hadron Collider (LHC) has already found out what gives mass to all the matter in the Universe. It is now trying to go even deeper into what makes up everything we see around us. Dr Marija Cauchi writes about her research that helped protect this atom smasher from itself. Photography by Jean Claude Vancell. http://www.um.edu.mt/think/crash-testing-the-largest-experiment-on-earth/

Stability of barrier buckets with zero RF-barrier separations

Energy Technology Data Exchange (ETDEWEB)

Ng, K.Y.; /Fermilab

2005-03-01

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

Death following traumatic brain injury in Drosophila is associated with intestinal barrier dysfunction

Science.gov (United States)

Katzenberger, Rebeccah J; Chtarbanova, Stanislava; Rimkus, Stacey A; Fischer, Julie A; Kaur, Gulpreet; Seppala, Jocelyn M; Swanson, Laura C; Zajac, Jocelyn E; Ganetzky, Barry; Wassarman, David A

2015-01-01

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Unfavorable TBI outcomes result from primary mechanical injuries to the brain and ensuing secondary non-mechanical injuries that are not limited to the brain. Our genome-wide association study of Drosophila melanogaster revealed that the probability of death following TBI is associated with single nucleotide polymorphisms in genes involved in tissue barrier function and glucose homeostasis. We found that TBI causes intestinal and blood–brain barrier dysfunction and that intestinal barrier dysfunction is highly correlated with the probability of death. Furthermore, we found that ingestion of glucose after a primary injury increases the probability of death through a secondary injury mechanism that exacerbates intestinal barrier dysfunction. Our results indicate that natural variation in the probability of death following TBI is due in part to genetic differences that affect intestinal barrier dysfunction. DOI: http://dx.doi.org/10.7554/eLife.04790.001 PMID:25742603

Barriers to the adoption of energy-saving technologies in the building sector: A survey study of Jing-jin-tang, China

International Nuclear Information System (INIS)

Du, Ping; Zheng, Li-Qun; Xie, Bai-Chen; Mahalingam, Arjun

2014-01-01

The building sector of China currently consumes 20% of the total energy consumption. Studies on barriers to the adoption of building energy-saving technologies are of great significance on implementing policies related to achieving energy-saving goals. This paper studied 15 barriers with the aid of information collected through questionnaires and semi-structured interviews. The respondents were 135 employees working in the Jing-jin-tang area. Based on the results of the factor analysis, the barriers were categorized into five groups: attitudes of stakeholders, policies and regulations, auxiliary resources, profitability, and adaptability of the technologies. Analysis of the entire sample showed that the stakeholders’ reluctance to use was the largest barrier, followed by high initial investment and low profitability. Further analysis showed that the occupation and designation of the respondents and the size of the enterprises that they served influenced their perspectives on the barriers. It was found that architects attributed more importance to the adoption of energy-saving technologies than contractors; barriers confronted by employees of large enterprises and small enterprises were different; managers perceived weaker barriers than frontline employees and were more optimistic about the prospect of building energy-saving technologies. Finally, policy recommendations were proposed based on these in-depth and targeted analyses. - Highlights: • Fifteen barriers to the adoption of energy-saving technologies are discussed. • Surveys are conducted in one of China's most technologically developed area. • The barriers are divided into 5 groups according to the results of factor analysis. • Barriers related to profitability greatly hamper the adoption of the technologies. • Comparative analyses show the background of respondents influence their viewpoints

Tunable Schottky barrier and high responsivity in graphene/Si-nanotip optoelectronic device

Science.gov (United States)

Di Bartolomeo, Antonio; Giubileo, Filippo; Luongo, Giuseppe; Iemmo, Laura; Martucciello, Nadia; Niu, Gang; Fraschke, Mirko; Skibitzki, Oliver; Schroeder, Thomas; Lupina, Grzegorz

2017-03-01

We demonstrate tunable Schottky barrier height and record photo-responsivity in a new-concept device made of a single-layer CVD graphene transferred onto a matrix of nanotips patterned on n-type Si wafer. The original layout, where nano-sized graphene/Si heterojunctions alternate to graphene areas exposed to the electric field of the Si substrate, which acts both as diode cathode and transistor gate, results in a two-terminal barristor with single-bias control of the Schottky barrier. The nanotip patterning favors light absorption, and the enhancement of the electric field at the tip apex improves photo-charge separation and enables internal gain by impact ionization. These features render the device a photodetector with responsivity (3 {{A}} {{{W}}}-1 for white LED light at 3 {{mW}} {{{cm}}}-2 intensity) almost an order of magnitude higher than commercial photodiodes. We extensively characterize the voltage and the temperature dependence of the device parameters, and prove that the multi-junction approach does not add extra-inhomogeneity to the Schottky barrier height distribution. We also introduce a new phenomenological graphene/semiconductor diode equation, which well describes the experimental I-V characteristics both in forward and reverse bias.

Energy Renovation of Danish Single-Family Houses

DEFF Research Database (Denmark)

Mortensen, Andrea

2015-01-01

. The results show that despite the barriers the owners can in fact be motivated to perform private energy renovations. A sound project economy is all-important for this to happen and it should if possible be supported by improvements in both comfort, indoor environment and architecture to increase......The PhD project is based on requirements from the European Union to reduce the energy consumption and on current renovation needs of and a huge energy saving potential in the Danish single-family houses from the 1960’s and 1970’s. The project focuses on the barriers for energy renovations...... of these houses and on defining motivation factors for the homeowners. The barriers are many and variating in influence and studies show that both professionals and homeowners are affected. The barriers range from lack of interest and knowledge to uncertainties about among others economy and technical solutions...

Predicting Traffic Flow in Local Area Networks by the Largest Lyapunov Exponent

Directory of Open Access Journals (Sweden)

Yan Liu

2016-01-01

Full Text Available The dynamics of network traffic are complex and nonlinear, and chaotic behaviors and their prediction, which play an important role in local area networks (LANs, are studied in detail, using the largest Lyapunov exponent. With the introduction of phase space reconstruction based on the time sequence, the high-dimensional traffic is projected onto the low dimension reconstructed phase space, and a reduced dynamic system is obtained from the dynamic system viewpoint. Then, a numerical method for computing the largest Lyapunov exponent of the low-dimensional dynamic system is presented. Further, the longest predictable time, which is related to chaotic behaviors in the system, is studied using the largest Lyapunov exponent, and the Wolf method is used to predict the evolution of the traffic in a local area network by both Dot and Interval predictions, and a reliable result is obtained by the presented method. As the conclusion, the results show that the largest Lyapunov exponent can be used to describe the sensitivity of the trajectory in the reconstructed phase space to the initial values. Moreover, Dot Prediction can effectively predict the flow burst. The numerical simulation also shows that the presented method is feasible and efficient for predicting the complex dynamic behaviors in LAN traffic, especially for congestion and attack in networks, which are the main two complex phenomena behaving as chaos in networks.

Homoepitaxial graphene tunnel barriers for spin transport (Presentation Recording)

Science.gov (United States)

Friedman, Adam L.

2015-09-01

Tunnel barriers are key elements for both charge-and spin-based electronics, offering devices with reduced power consumption and new paradigms for information processing. Such devices require mating dissimilar materials, raising issues of heteroepitaxy, interface stability, and electronic states that severely complicate fabrication and compromise performance. Graphene is the perfect tunnel barrier. It is an insulator out-of-plane, possesses a defect-free, linear habit, and is impervious to interdiffusion. Nonetheless, true tunneling between two stacked graphene layers is not possible in environmental conditions (magnetic field, temperature, etc.) usable for electronics applications. However, two stacked graphene layers can be decoupled using chemical functionalization. Here, we demonstrate homoepitaxial tunnel barrier devices in which graphene serves as both the tunnel barrier and the high mobility transport channel. Beginning with multilayer graphene, we fluorinate or hydrogenate the top layer to decouple it from the bottom layer, so that it serves as a single monolayer tunnel barrier for both charge and spin injection into the lower graphene transport channel. We demonstrate successful tunneling by measuring non-linear IV curves, and a weakly temperature dependent zero bias resistance. We perform lateral transport of spin currents in non-local spin-valve structures and determine spin lifetimes with the non-local Hanle effect to be commensurate with previous studies (~200 ps). However, we also demonstrate the highest spin polarization efficiencies (~45%) yet measured in graphene-based spin devices [1]. [1] A.L. Friedman, et al., Homoepitaxial tunnel barriers with functionalized graphene-on-graphene for charge and spin transport, Nat. Comm. 5, 3161 (2014).

Safety- barrier diagrams

DEFF Research Database (Denmark)

Duijm, Nijs Jan

2008-01-01

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

Safety-barrier diagrams

DEFF Research Database (Denmark)

Duijm, Nijs Jan

2007-01-01

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

Vehicle barrier systems

International Nuclear Information System (INIS)

Sena, P.A.

1986-01-01

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

Dynamics of Multi-kinks in the Presence of Wells and Barriers

International Nuclear Information System (INIS)

Goatham, S.W.; Mannering, L.E.; Hann, R.; Krusch, S.

2011-01-01

Sine-Gordon kinks are non-dispersive solutions in a much studied integrable system. Recent studies on sine-Gordon kinks with space-dependent square-well-type potentials have revealed interesting dynamics of a single kink interacting with wells and barriers. In this paper, we study a class of smooth space-dependent potentials and discuss the dynamics of one kink in the presence of different wells. We also present values for the critical velocity for different types of barriers. Furthermore, we study two kinks interacting with various wells and describe interesting trajectories such as double-trapping, kink knock-out and double-escape. (authors)

Elimination of two level fluctuators in superconducting quantum bits by an epitaxial tunnel barrier

International Nuclear Information System (INIS)

Oh, Seongshik; Cicak, Katarina; Kline, Jeffrey S.; Sillanpaeae, Mika A.; Osborn, Kevin D.; Whittaker, Jed D.; Simmonds, Raymond W.; Pappas, David P.

2006-01-01

Quantum computing based on Josephson junction technology is considered promising due to its scalable architecture. However, decoherence is a major obstacle. Here, we report evidence for improved Josephson quantum bits (qubits) using a single-crystal Al 2 O 3 tunnel barrier. We have found an ∼80% reduction in the density of the spectral splittings that indicate the existence of two-level fluctators (TLFs) in amorphous tunnel barriers. The residual ∼20% TLFs can be attributed to interfacial effects that may be further reduced by different electrode materials. These results show that decoherence sources in the tunnel barrier of Josephson qubits can be identified and eliminated

Barrier for cold-fusion production of superheavy elements

International Nuclear Information System (INIS)

Ichikawa, Takatoshi; Iwamoto, Akira; Moeller, Peter; Sierk, Arnold J.

2005-01-01

We estimate the fusion-barrier height B fu (two-body) for approaching ions in cold-fusion reactions in a model where the projectile deformation and quadrupole zero-point vibrational energy are taken into account. This barrier height is defined as the barrier energy at the target and projectile separation distance where an original oblate deformation of projectile and/or target caused by a repulsive Coulomb force turns into a large prolate deformation caused by the attractive nuclear force as the target and projectile come closer. The instability develops before touching because the attractive short-range nuclear force overcomes the repulsive Coulomb force and the shape-stabilizing effect of shell structure. The shell structure of the doubly magic 208 Pb target is sufficiently strong that its shape remains very close to spherical in all cases studied here. The fusion potential for approaching ions in the two-body channel is calculated in the macroscopic-microscopic model with the quadrupole vibrational zero-point energy obtained in the WKB approximation. We compare our results with data from 10 experimental cold-fusion reactions and with the Bass barriers. Differences and similarities between the Yukawa-plus-exponential model and the Bass model are discussed. We also calculate five-dimensional potential-energy surfaces for the single compound system and show that well-established fission and fusion valleys are both present. For heavy systems, B fu (two-body) becomes lower than the fission barrier just beyond the ground state of the compound system. In the vicinity of this transition, the optimum collision energy for formation of evaporation residues can be expected to depend in a delicate fashion on the interplay among B fu (two-body) , the fusion valley, the fission barrier of the compound system, and the one- and two-neutron separation energies S 1n and S 2n . We discuss these issues in detail and calculate fission-barrier heights. Except for reactions in which

Lagisza, world's largest CFB boiler, begins commercial operation

Energy Technology Data Exchange (ETDEWEB)

Nuortimo, K. [Foster Wheeler, Varkaus (Finland)

2010-04-15

Early operating experience with the Lagisza circulating fluidised bed (CFB) boiler in Poland - the world's largest such boiler to date, and also the first one with supercritical steam conditions - has been positive. 3 figs., 4 tabs.

Temporal properties of seismicity and largest earthquakes in SE Carpathians

Directory of Open Access Journals (Sweden)

S. Byrdina

2006-01-01

Full Text Available In order to estimate the hazard rate distribution of the largest seismic events in Vrancea, South-Eastern Carpathians, we study temporal properties of historical and instrumental catalogues of seismicity. First, on the basis of Generalized Extreme Value theory we estimate the average return period of the largest events. Then, following Bak et al. (2002 and Corral (2005a, we study scaling properties of recurrence times between earthquakes in appropriate spatial volumes. We come to the conclusion that the seismicity is temporally clustered, and that the distribution of recurrence times is significantly different from a Poisson process even for times largely exceeding corresponding periods of foreshock and aftershock activity. Modeling the recurrence times by a gamma distributed variable, we finally estimate hazard rates with respect to the time elapsed from the last large earthquake.

PNNL supercomputer to become largest computing resource on the Grid

CERN Multimedia

2002-01-01

Hewlett Packard announced that the US DOE Pacific Northwest National Laboratory will connect a 9.3-teraflop HP supercomputer to the DOE Science Grid. This will be the largest supercomputer attached to a computer grid anywhere in the world (1 page).

Worlds largest particle physics laboratory selects Proxim Wireless Mesh

CERN Multimedia

2007-01-01

"Proxim Wireless has announced that the European Organization for Nuclear Research (CERN), the world's largest particle physics laboratory and the birthplace of the World Wide Web, is using it's ORiNOCO AP-4000 mesh access points to extend the range of the laboratory's Wi-Fi network and to provide continuous monitoring of the lab's calorimeters" (1/2 page)

Extremal surface barriers

International Nuclear Information System (INIS)

Engelhardt, Netta; Wall, Aron C.

2014-01-01

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

Defect analysis in low temperature atomic layer deposited Al{sub 2}O{sub 3} and physical vapor deposited SiO barrier films and combination of both to achieve high quality moisture barriers

Energy Technology Data Exchange (ETDEWEB)

Maindron, Tony, E-mail: tony.maindron@cea.fr; Jullien, Tony; André, Agathe [Université Grenoble-Alpes, CEA, LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France)

2016-05-15

Al{sub 2}O{sub 3} [20 nm, atomic layer deposition (ALD)] and SiO films' [25 nm, physical vacuum deposition (PVD)] single barriers as well as hybrid barriers of the Al{sub 2}O{sub 3}/SiO or SiO/Al{sub 2}O{sub 3} have been deposited onto single 100 nm thick tris-(8-hydroxyquinoline) aluminum (AlQ{sub 3}) organic films made onto silicon wafers. The defects in the different barrier layers could be easily observed as nonfluorescent AlQ{sub 3} black spots, under ultraviolet light on the different systems stored into accelerated aging conditions (85 °C/85% RH, ∼2000 h). It has been observed that all devices containing an Al{sub 2}O{sub 3} layer present a lag time τ from which defect densities of the different systems start to increase significantly. This is coherent with the supposed pinhole-free nature of fresh, ALD-deposited, Al{sub 2}O{sub 3} films. For t > τ, the number of defect grows linearly with storage time. For devices with the single Al{sub 2}O{sub 3} barrier layer, τ has been estimated to be 64 h. For t > τ, the defect occurrence rate has been calculated to be 0.268/cm{sup 2}/h. Then, a total failure of fluorescence of the AlQ{sub 3} film appears between 520 and 670 h, indicating that the Al{sub 2}O{sub 3} barrier has been totally degraded by the hot moisture. Interestingly, the device with the hybrid barrier SiO/Al{sub 2}O{sub 3} shows the same characteristics as the device with the single Al{sub 2}O{sub 3} barrier (τ = 59 h; 0.246/cm{sup 2}/h for t > τ), indicating that Al{sub 2}O{sub 3} ALD is the factor that limits the performance of the barrier system when it is directly exposed to moisture condensation. At the end of the storage period (1410 h), the defect density for the system with the hybrid SiO/Al{sub 2}O{sub 3} barrier is 120/cm{sup 2}. The best sequence has been obtained when Al{sub 2}O{sub 3} is passivated by the SiO layer (Al{sub 2}O{sub 3}/SiO). In that case, a large lag time of 795 h and a very

Discovery of the largest orbweaving spider species: the evolution of gigantism in Nephila.

Science.gov (United States)

Kuntner, Matjaz; Coddington, Jonathan A

2009-10-21

More than 41,000 spider species are known with about 400-500 added each year, but for some well-known groups, such as the giant golden orbweavers, Nephila, the last valid described species dates from the 19(th) century. Nephila are renowned for being the largest web-spinning spiders, making the largest orb webs, and are model organisms for the study of extreme sexual size dimorphism (SSD) and sexual biology. Here, we report on the discovery of a new, giant Nephila species from Africa and Madagascar, and review size evolution and SSD in Nephilidae. We formally describe N. komaci sp. nov., the largest web spinning species known, and place the species in phylogenetic context to reconstruct the evolution of mean size (via squared change parsimony). We then test female and male mean size correlation using phylogenetically independent contrasts, and simulate nephilid body size evolution using Monte Carlo statistics. Nephila females increased in size almost monotonically to establish a mostly African clade of true giants. In contrast, Nephila male size is effectively decoupled and hovers around values roughly one fifth of female size. Although N. komaci females are the largest Nephila yet discovered, the males are also large and thus their SSD is not exceptional.

Discovery of the largest orbweaving spider species: the evolution of gigantism in Nephila.

Directory of Open Access Journals (Sweden)

Matjaz Kuntner

2009-10-01

Full Text Available More than 41,000 spider species are known with about 400-500 added each year, but for some well-known groups, such as the giant golden orbweavers, Nephila, the last valid described species dates from the 19(th century. Nephila are renowned for being the largest web-spinning spiders, making the largest orb webs, and are model organisms for the study of extreme sexual size dimorphism (SSD and sexual biology. Here, we report on the discovery of a new, giant Nephila species from Africa and Madagascar, and review size evolution and SSD in Nephilidae.We formally describe N. komaci sp. nov., the largest web spinning species known, and place the species in phylogenetic context to reconstruct the evolution of mean size (via squared change parsimony. We then test female and male mean size correlation using phylogenetically independent contrasts, and simulate nephilid body size evolution using Monte Carlo statistics.Nephila females increased in size almost monotonically to establish a mostly African clade of true giants. In contrast, Nephila male size is effectively decoupled and hovers around values roughly one fifth of female size. Although N. komaci females are the largest Nephila yet discovered, the males are also large and thus their SSD is not exceptional.

On the statistics of the largest geomagnetic storms per solar cycle

International Nuclear Information System (INIS)

Siscoe, G.L.

1976-01-01

The theory of extreme value statistics is applied to the first, second, and third largest geomagnetic storms in nine solar cycles measured by the average half-daily aa indices compiled by Mayaud. Analytic expressions giving the probability of the extremes per solar cycle as a contour function of storm magnitude are obtained by least squares fitting of the observations to the appropriate theoretical extreme value probability functions. The results are used to obtain the statistical characteristics (mode, median, mean, and standard deviation) for the extreme values. The results are applied to find the expected range of extreme values in a set as a function of the number of solar cycles in the set. We find that the expected range of the largest storm is quite narrow and is larger for the second and third largest storms. The observed range of the extreme half-daily aa index for the nine solar cycles is 354--546 γ. In a set of 100 cycles the range is expanded esentially to 311--680γ, an increase of only 39% in the range. The result supports the argument for a change in solar cycle statistics in the latter part of the Seventeenth Century (the Maunder minimum)

Measurements and Simulations of Surface Dielectric Barrier Discharges Used as Plasma Actuators

Science.gov (United States)

Hoskinson, Alan R.

2012-01-01

This report is a Ph.D. dissertation performed under NRA cooperative agreement and submitted as part of the final report. Asymmetric surface dielectric barrier discharges (DBDs) have shown promise for use as aerodynamic actuators for active flow control. In this project we studied DBD actuators experimentally and numerically. Our DBDs used a symmetric triangular high voltage waveform to generate plasma in atmospheric pressure air. Time-averaged measurements indicated that the induced force of a single barrier actuator design (one electrode insulated from the plasma) can be increased exponentially above the results of previous studies by decreasing both the length and thickness of the electrode exposed to the plasma. This increased force may allow these devices to control flow separation in a wider range of flow environments. Experiments using an intensified digital camera to examine the plasma on time scales of a few nanoseconds showed that, in addition to the previously-observed filamentary and jet-like plasma structures, discharges with very thin exposed electrodes exhibited a weak but constant plasma immediately adjacent to those electrodes. In double-barrier actuators (both electrodes insulated), decreasing the diameter of the narrower electrode lead to increasing forces, and recorded images showed the simultaneous existence of both filamentary and jet-like plasma structures. The development and application of a time-dependent, two-dimensional computational fluid plasma model has aided in understanding the detailed physics of surface DBDs at all-time scales. For simulated single-barrier discharges, the model qualitatively reproduced the filamentary and jet-like micro-discharge structures. The model was somewhat successful in reproducing the observed characteristics of double-barrier actuators. For both actuator geometries, the model indicated that the majority of the forces induced on the neutral gas occur in between micro-discharges as the plasmas decay.

Output voltage calculations in double barrier magnetic tunnel junctions with asymmetric voltage behavior

KAUST Repository

Useinov, Arthur; Mryasov, Oleg; Kosel, Jü rgen

2011-01-01

In this paper we study the asymmetric voltage behavior (AVB) of the tunnel magnetoresistance (TMR) for single and double barrier magnetic tunnel junctions (MTJs) in range of a quasi-classical free electron model. Numerical calculations of the TMR

Multilayer moisture barrier

Science.gov (United States)

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

2015-04-21

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

Expectations of barriers to psychosocial care: views of parents and adolescents in the community.

Science.gov (United States)

Nanninga, Marieke; Reijneveld, Sijmen A; Knorth, Erik J; Jansen, Danielle E M C

2016-01-01

Parents with a child suffering from psychosocial problems frequently experience barriers to psychosocial care, which may hinder access. Expectations of barriers may have the same effect, but evidence is lacking. The aim of this study is to examine parents' and adolescents' expectations of barriers regarding psychosocial care for the child, along with associated child and family characteristics. We obtained data on an age-stratified random sample of school children/pupils aged 4-18 via questionnaires (N = 666; response rate 70.3 %). Expectations of barriers to psychosocial care were measured with the "Barriers to Treatment Participation Scale-Expectancies" questionnaire (BTPS-exp). Results showed that 64 % of the parents of children below age 12, 59 % of the parents of adolescents (age 12-18), and 84 % of the adolescents expected one or more barriers. Parents and adolescents expected barriers most frequently with respect to irrelevance of treatment. Mainly parents with low educational level and their adolescents expected barriers regarding treatment, and quite a few characteristics of parents of adolescents were associated with expecting multiple barriers regarding treatment demands and issues, for example, single parents, parents of lower educational level and of adolescent boys, and parents of adolescents with psychosocial problems. We conclude that adolescents especially, but also their parents and parents of younger children, expect major barriers to psychosocial care, which may greatly hinder appropriate care seeking. This evidence may support professionals and policymakers in their attempts to improve access to psychosocial care.

Revisiting the phylogeny of Ocellularieae, the second largest tribe within Graphidaceae (lichenized Ascomycota: Ostropales)

Science.gov (United States)

Ekaphan Kraichak; Sittiporn Parnmen; Robert Lücking; Eimy Rivas Plata; Andre Aptroot; Marcela E.S. Caceres; Damien Ertz; Armin Mangold; Joel A. Mercado-Diaz; Khwanruan Papong; Dries Van der Broeck; Gothamie Weerakoon; H. Thorsten. Lumbsch; NO-VALUE

2014-01-01

We present an updated 3-locus molecular phylogeny of tribe Ocellularieae, the second largest tribe within subfamily Graphidoideae in the Graphidaceae. Adding 165 newly generated sequences from the mitochondrial small subunit rDNA (mtSSU), the nuclear large subunit rDNA (nuLSU), and the second largest subunit of the DNA-directed RNA polymerase II (RPB2), we currently...

Identifying barriers to aboriginal renewable energy deployment in Canada

International Nuclear Information System (INIS)

Krupa, Joel

2012-01-01

As one of the largest and wealthiest countries in the world, Canada stands well-positioned to take advantage of ongoing growth in North American demand for primary energy supply by expanding domestic delivery of renewable energy generation to internationally interconnected electric grids across the country. There are myriad benefits of adopting the renewable energy approach to development—as the province of Ontario has acknowledged through the implementation of their 2009 Green Energy Act—including drastic reductions in carbon emissions, the decommissioning of existing fossil fuel power generation that cause serious public health problems, and opportunities for sustainable development at the community level. One group in particular stands poised to shape these debates. In Canada, historically marginalized Aboriginal peoples remain one of the groups with the greatest potential for meeting these enormous renewable energy deployment needs. Aboriginal involvement in renewable energy generation in Canada has been as diverse as Canada's Aboriginal peoples and groups have already adopted a range of different solutions to meet energy supply needs. However, many significant barriers exist that prevent this diverse cultural group from reaching its full potential. The article identifies some of these shortcomings and analyzes their roots. - Highlights: ► Renewable energy is one of the most important sustainable development opportunities today. ► Aboriginal-led renewable development could dramatically increase Canadian supply. ► Surmountable barriers are identified.

Nurses' knowledge and barriers regarding pain management in intensive care units.

Science.gov (United States)

Wang, Hsiang-Ling; Tsai, Yun-Fang

2010-11-01

To explore nurses' knowledge and barriers regarding pain management in intensive care units. Pain is a common and treatable condition among intensive care patients. Quality care of these patients depends on the pain knowledge and pain management skills of critical care nurses. However, no single study has explored these nurses' knowledge of and perceived barriers to pain management in Taiwan. A cross-sectional study. Intensive care unit nurses (n = 370) were recruited from 16 hospitals chosen by stratified sampling across Taipei County in Taiwan. Data were collected on nurses' knowledge of pain management using the Nurses' Knowledge and Attitudes Survey-Taiwanese version, on perceived barriers to pain management using a researcher-developed scale and on background information. The overall average correct response rate for the knowledge scale was 53.4%, indicating poor knowledge of pain management. The top barrier to managing pain identified by these nurses was 'giving proper pain prescription needs doctor's approval; can't depend on me'. Knowledge of pain management was significantly and negatively related to perceived barriers to pain management. In addition, scores for knowledge and perceived barriers differed significantly by specific intensive care unit. Knowledge also differed significantly by nurses' education level, clinical competence level (nursing ladder) and hospital accreditation category. Our results indicate an urgent need to strengthen pain education by including case analysis for intensive care nurses in Taiwan. Pain education should target knowledge deficits and barriers to changing pain management approaches for Taiwanese nurses in intensive care units. © 2010 Blackwell Publishing Ltd.

CERN, World's largest particle physics lab, selects Progress SonicMQ

CERN Document Server

2007-01-01

"Progress Software Corporation (NADAQ: PRGS), a global supplier of application insfrastructure software used to develop, deploy, integrate and manage business applications, today announced that CERN the world's largest physis laboratory and particle accelerator, has chosen Progress® SonicMQ® for mission-critical message delivery." (1 page)

Synchrotron Emission on the Largest Scales: Radio Detection of the ...

Indian Academy of Sciences (India)

Abstract. Shocks and turbulence generated during large-scale structure formation are predicted to produce large-scale, low surface-brightness synchrotron emission. On the largest scales, this emission is globally correlated with the thermal baryon distribution, and constitutes the 'syn- chrotron cosmic-web'. I present the ...

Distribution of the Largest Eigenvalues of the Levi-Smirnov Ensemble

International Nuclear Information System (INIS)

Wieczorek, W.

2004-01-01

We calculate the distribution of the k-th largest eigenvalue in the random matrix Levi - Smirnov Ensemble (LSE), using the spectral dualism between LSE and chiral Gaussian Unitary Ensemble (GUE). Then we reconstruct universal spectral oscillations and we investigate an asymptotic behavior of the spectral distribution. (author)

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

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

A Lactobacillus mutant capable of accumulating long-chain polyphosphates that enhance intestinal barrier function.

Science.gov (United States)

Saiki, Asako; Ishida, Yasuaki; Segawa, Shuichi; Hirota, Ryuichi; Nakamura, Takeshi; Kuroda, Akio

2016-05-01

Inorganic polyphosphate (polyP) was previously identified as a probiotic-derived substance that enhances intestinal barrier function. PolyP-accumulating bacteria are expected to have beneficial effects on the human gastrointestinal tract. In this study, we selected Lactobacillus paracasei JCM 1163 as a strain with the potential to accumulate polyP, because among the probiotic bacteria stored in our laboratory, it had the largest amount of polyP. The chain length of polyP accumulated in L. paracasei JCM 1163 was approximately 700 phosphate (Pi) residues. L. paracasei JCM 1163 accumulated polyP when Pi was added to Pi-starved cells. We further improved the ability of L. paracasei JCM 1163 to accumulate polyP by nitrosoguanidine mutagenesis. The mutant accumulated polyP at a level of 1500 nmol/mg protein-approximately 190 times that of the wild-type strain. PolyP extracted from the L. paracasei JCM 1163 significantly suppressed the oxidant-induced intestinal permeability in mouse small intestine. In conclusion, we have succeeded in breeding the polyP-accumulating Lactobacillus mutant that is expected to enhance intestinal barrier function.

Perceived barriers to effective job performance among nursing assistants in long-term care.

Science.gov (United States)

Parmelee, Patricia A; Laszlo, Mary C; Taylor, Jo A

2009-10-01

This research explored perceived barriers to job performance among a national sample of nursing assistants (NAs). Specific objectives were (1) to clarify which of the problems identified by previous research are most troublesome for NAs, (2) to develop a reliable quantitative measure of perceived barriers to job performance, and (3) to test construct validity of the measure vis-à-vis work-related psychological empowerment and job satisfaction. Nursing assistants attending the 2006 national conference of the National Association of Health Care Assistants completed a paper-and-pencil survey including 33 barriers to job performance and standardized measures of empowerment and job satisfaction. The barriers were also rated by a small sample of NAs at a single Georgia nursing home. Factor analysis of barriers items yielded a 30-item Nursing Assistants Barriers Scale (NABS) comprising 6 subscales: Teamwork, Exclusion, Respect, Workload, Work Stress, and New NAs. Lack of teamwork and exclusion from communication processes were rated as most problematic by both samples. The 6 NABS subscales were significantly and independently associated with empowerment and satisfaction; different barriers predicted the 2 constructs. This study is a first step toward quantitative assessment of NAs' perceptions of barriers to doing their jobs. Primary limitations are the select sample and use of a job satisfaction measure that may have artificially inflated correlations with the NABS. Nonetheless, results confirm the validity of the new scale as an operationalization of the barriers construct. The concept of barriers to job performance is a unique construct from work empowerment and satisfaction with one's job. Nursing assistants clearly differentiate various barriers, converging on workload and lack of teamwork as most problematic. Further work is needed to substantiate validity and reliability of the NABS, particularly with respect to NAs' actual job performance, intent to stay on the

Health insurance premium increases for the 5 largest school districts in the United States, 2004-2008.

Science.gov (United States)

Cantillo, John R

2010-03-01

Local school districts are often one of the largest, if not the largest, employers in their respective communities. Like many large employers, school districts offer health insurance to their employees. There is a lack of information about the rate of health insurance premiums in US school districts relative to other employers. To assess the change in the costs of healthcare insurance in the 5 largest public school districts in the United States, between 2004 and 2008, as representative of large public employers in the country. Data for this study were drawn exclusively from a survey sent to the 5 largest public school districts in the United States. The survey requested responses on 3 data elements for each benefit plan offered from 2004 through 2008; these included enrollment, employee costs, and employer costs. The premium growth for the 5 largest school districts has slowed down and is consistent with other purchasers-Kaiser/Health Research & Educational Trust and the Federal Employee Health Benefit Program. The average increase in health insurance premium for the schools was 5.9% in 2008, and the average annual growth rate over the study period was 7.5%. For family coverage, these schools provide the most generous employer contribution (80.8%) compared with the employer contribution reported by other employers (73.5%) for 2008. Often the largest employers in their communities, school districts demonstrate a commitment to provide choice of benefits and affordability for employees and their families. Despite constraints typical of public employers, the 5 largest school districts in the United States have decelerated in premium growth consistent with other purchasers, albeit at a slower pace.

A Qualitative Examination of Youth Voice in the Decision-Making Process within the 4-H Youth Development Program: Promoting Promising Practices in Overcoming Barriers

Directory of Open Access Journals (Sweden)

Janet Fox

2008-12-01

Full Text Available This paper discusses a national study designed to identify and describe obstacles to youth voice in the decision-making process in the 4-H youth development program from the perception of three distinct populations - State 4-H Program Leaders, 4-H State Youth Development Specialists, and 4-H Youth Agents/Educators. When examining these professionals’ views on the barriers affecting youth voice in the decision-making process, time and scheduling seem to consistently present the largest barrier to youth voice. Involvement in the decision-making process provides a wide range of hurdles including the opportunity structures, involvement procedures, representation and dynamics within the process. Adult power and control provides a significant hurdle to authentic engagement of youth voice in the decision-making progress. Respect barriers were described by concepts such as preconceived notions, trust and valuing input. Additional barriers were identified including organizational culture, lack of transportation, lack of knowledge/experience, lack of preparation, lack of training, fear, misguided leadership, unclear expectations, participation, staffing and lack of resources.

The largest subsea hot tap (future tap flange) at Angel Field, Australia

Energy Technology Data Exchange (ETDEWEB)

Lad, Deepak; Drysdale, Colin [T.D. Williamson (United States); Naidoo, Sashie [T.D. Williamson (Australia)

2008-07-01

A subsea hot tap was conducted near the gas production platforms in Angel Field, Australia in September 2007 and verified as the largest no. 900 subsea hot tap by Australian authorities. This paper outlines the subsea tapping process, risks and safety issues in deep water environment, including the need to ensure 100% system accuracy and that the machine fluids used to operate the subsea tapping machines were environmentally friendly. The testing phase included land and water testing. In the land tests, issues relating to metal hardness, temperature, pressure and ocean currents that affected machine stability, torque and cutting rate were considered. All preliminary design and testing focused on being able to mount the tapping machine to a pre-existing hot-tap flange and conduct the tapping operation, start to finish, preferably without changing the cutter. The water depth tests took place inside a pressurized, underwater hyperbaric chamber. The equipment repeated the land testing process in conditions duplicating that of the actual project site. Timing was also measured in multiple climatic conditions (except water depth) to obtain an estimation of various scenarios. The field tapping process was conducted without problems in over six hours with a single cutter and without any stalls. (author)

Properties of a GaAs Single Electron Path Switching Node Device Using a Single Quantum Dot for Hexagonal BDD Quantum Circuits

International Nuclear Information System (INIS)

Nakamura, Tatsuya; Abe, Yuji; Kasai, Seiya; Hasegawa, Hideki; Hashizume, Tamotsu

2006-01-01

A new single electron (SE) binary-decision diagram (BDD) node device having a single quantum dot connected to three nanowire branches through tunnel barriers was fabricated using etched AlGaAs/GaAs nanowires and nanometer-sized Schottky wrap gates (WPGs), and their operation was characterized experimentally, for the hexagonal BDD quantum circuit. Fabricated devices showed clear and steep single electron pass switching by applying only an input voltage signal, which was completely different from switching properties in the previous SE BDD node devices composed of two single electron switches. As the possible switching mechanism, the correlation between the probabilities of tunnelling thorough a single quantum dot in exit branches was discussed

Understanding barriers to commercial-scale carbon capture and sequestration in the United States: An empirical assessment

International Nuclear Information System (INIS)

Davies, Lincoln L.; Uchitel, Kirsten; Ruple, John

2013-01-01

Although a potentially useful climate change mitigation tool, carbon capture and sequestration (CCS) efforts in the United States remain mired in demonstration and development. Prior studies suggest numerous reasons for this stagnation. This article empirically assesses those claims. Using an anonymous opinion survey completed by 229 CCS experts, we identified four primary barriers to CCS commercialization: (1) cost and cost recovery, (2) lack of a price signal or financial incentive, (3) long-term liability risks, and (4) lack of a comprehensive regulatory regime. These results give empirical weight to previous studies suggesting that CCS cost (and cost recovery) and liability risks are primary barriers to the technology. However, the need for comprehensive rather than piecemeal CCS regulation represents an emerging concern not previously singled out in the literature. Our results clearly show that the CCS community sees fragmented regulation as one of the most significant barriers to CCS deployment. Specifically, industry is united in its preference for a federal regulatory floor that is subject to state-level administration and sensitive to local conditions. Likewise, CCS experts share broad confidence in the technology's readiness, despite continued calls for commercial-scale demonstration projects before CCS is widely deployed. - Highlights: • We developed and distributed a unique CCS opinion survey. • Our analysis confirmed cost and liability as primary barriers to CCS deployment. • We identified regulatory barriers to CCS not previously singled out in the literature. • We address the need for comprehensive rather than piecemeal CCS regulation

Discovery of the Largest Orbweaving Spider Species: The Evolution of Gigantism in Nephila

OpenAIRE

Kuntner, Matja?; Coddington, Jonathan A.

2009-01-01

Background More than 41,000 spider species are known with about 400?500 added each year, but for some well-known groups, such as the giant golden orbweavers, Nephila, the last valid described species dates from the 19th century. Nephila are renowned for being the largest web-spinning spiders, making the largest orb webs, and are model organisms for the study of extreme sexual size dimorphism (SSD) and sexual biology. Here, we report on the discovery of a new, giant Nephila species from Africa...

Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithography

Science.gov (United States)

Pascher, Nikola; Hennel, Szymon; Mueller, Susanne; Fuhrer, Andreas

2016-08-01

A four-terminal donor quantum dot (QD) is used to characterize potential barriers between degenerately doped nanoscale contacts. The QD is fabricated by hydrogen-resist lithography on Si(001) in combination with n-type doping by phosphine. The four contacts have different separations (d = 9, 12, 16 and 29 nm) to the central 6 nm × 6 nm QD island, leading to different tunnel and capacitive coupling. Cryogenic transport measurements in the Coulomb-blockade (CB) regime are used to characterize these tunnel barriers. We find that field enhancement near the apex of narrow dopant leads is an important effect that influences both barrier breakdown and the magnitude of the tunnel current in the CB transport regime. From CB-spectroscopy measurements, we extract the mutual capacitances between the QD and the four contacts, which scale inversely with the contact separation d. The capacitances are in excellent agreement with numerical values calculated from the pattern geometry in the hydrogen resist. Furthermore, we show that by engineering the source-drain tunnel barriers to be asymmetric, we obtain a much simpler excited-state spectrum of the QD, which can be directly linked to the orbital single-particle spectrum.

Skin barrier function

DEFF Research Database (Denmark)

2016-01-01

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

Transmission through a potential barrier in Luttinger liquids with a topological spin gap

Science.gov (United States)

Kainaris, Nikolaos; Carr, Sam T.; Mirlin, Alexander D.

2018-03-01

We study theoretically the transport of the one-dimensional single-channel interacting electron gas through a strong potential barrier in the parameter regime where the spin sector of the low-energy theory is gapped by interaction (Luther-Emery liquid). There are two distinct phases of this nature, of which one is of particular interest as it exhibits nontrivial interaction-induced topological properties. Focusing on this phase and using bosonization and an expansion in the tunneling strength we calculate the conductance through the barrier as a function of the temperature as well as the local density of states (LDOS) at the barrier. Our main result concerns the mechanism of bound-state-mediated tunneling. The characteristic feature of the topological phase is the emergence of protected zero-energy bound states with fractional spin located at the impurity position. By flipping this fractional spin, single electrons can tunnel across the impurity even though the bulk spectrum for spin excitations is gapped. This results in a finite LDOS below the bulk gap and in a nonmonotonic behavior of the conductance. The system represents an important physical example of an interacting symmetry-protected topological phase, which combines features of a topological spin insulator and a topological charge metal, in which the topology can be probed by measuring transport properties.

Spin-filtering junctions with double ferroelectric barriers

International Nuclear Information System (INIS)

Yan, Ju; Ding-Yu, Xing

2009-01-01

An FS/FE/NS/FE/FS double tunnel junction is suggested to have the ability to inject, modulate and detect the spin-polarized current electrically in a single device, where FS is the ferromagnetic semiconductor electrode, NS is the nonmagnetic semiconductor, and FE the ferroelectric barrier. The spin polarization of the current injected into the NS region can be switched between a highly spin-polarized state and a spin unpolarized state. The high spin polarization may be detected by measuring the tunneling magnetoresistance ratio of the double tunnel junction

Laser-assisted cataract surgery: benefits and barriers.

Science.gov (United States)

Hatch, Kathryn M; Talamo, Jonathan H

2014-01-01

The use of the femtosecond laser (FSL) in cataract surgery may represent the largest advancement in the field since the inception of phacoemulsification. The goal of this review is to outline the benefits of and barriers to this technology. There are several significant potential benefits of the FSL in cataract surgery over conventional manual cataract surgery: precise capsulotomy formation, clear corneal and limbal relaxing incision construction, lens fragmentation, and lens softening. Evidence suggests that refractive benefits include more precise effective lens position as well as reduced effective phacoemulsification time with the use of FSL compared with manual surgery. Patients with conditions such as Fuchs' endothelial dystrophy, pseudoexfoliation, history of trauma, or brunescent cataracts may particularly benefit from this technology. There are significant financial and logistical issues to consider prior to the purchase of a FSL, including the cost of the laser, and charges to patients, and how the laser affects the patient flow in the operating room. The FSL may significantly change the current approach to cataract surgery.

Mechanisms of oxygen permeation through plastic films and barrier coatings

International Nuclear Information System (INIS)

Wilski, Stefan; Wipperfürth, Jens; Jaritz, Montgomery; Kirchheim, Dennis; Dahlmann, Rainer; Hopmann, Christian; Mitschker, Felix; Awakowicz, Peter

2017-01-01

Oxygen and water vapour permeation through plastic films in food packaging or other applications with high demands on permeation are prevented by inorganic barrier films. Most of the permeation occurs through small defects (<3 µ m) in the barrier coating. The defects were visualized by etching with reactive oxygen in a capacitively coupled plasma and subsequent SEM imaging. In this work, defects in SiO x -coatings deposited by plasma-enhanced chemical vapour deposition on polyethylene terephthalate (PET) are investigated and the mass transport through the polymer is simulated in a 3D approach. Calculations of single defects showed that there is no linear correlation between the defect area and the resulting permeability. The influence of adjacent defects in different distances was observed and led to flow reduction functions depending on the defect spacing and defect area. A critical defect spacing where no interaction between defects occurs was found and compared to other findings. According to the superposition principle, the permeability of single defects was added up and compared to experimentally determined oxygen permeation. The results showed the same trend of decreasing permeability with decreasing defect densities. (paper)

MO-D-213-07: RadShield: Semi- Automated Calculation of Air Kerma Rate and Barrier Thickness

International Nuclear Information System (INIS)

DeLorenzo, M; Wu, D; Rutel, I; Yang, K

2015-01-01

Purpose: To develop the first Java-based semi-automated calculation program intended to aid professional radiation shielding design. Air-kerma rate and barrier thickness calculations are performed by implementing NCRP Report 147 formalism into a Graphical User Interface (GUI). The ultimate aim of this newly created software package is to reduce errors and improve radiographic and fluoroscopic room designs over manual approaches. Methods: Floor plans are first imported as images into the RadShield software program. These plans serve as templates for drawing barriers, occupied regions and x-ray tube locations. We have implemented sub-GUIs that allow the specification in regions and equipment for occupancy factors, design goals, number of patients, primary beam directions, source-to-patient distances and workload distributions. Once the user enters the above parameters, the program automatically calculates air-kerma rate at sampled points beyond all barriers. For each sample point, a corresponding minimum barrier thickness is calculated to meet the design goal. RadShield allows control over preshielding, sample point location and material types. Results: A functional GUI package was developed and tested. Examination of sample walls and source distributions yields a maximum percent difference of less than 0.1% between hand-calculated air-kerma rates and RadShield. Conclusion: The initial results demonstrated that RadShield calculates air-kerma rates and required barrier thicknesses with reliable accuracy and can be used to make radiation shielding design more efficient and accurate. This newly developed approach differs from conventional calculation methods in that it finds air-kerma rates and thickness requirements for many points outside the barriers, stores the information and selects the largest value needed to comply with NCRP Report 147 design goals. Floor plans, parameters, designs and reports can be saved and accessed later for modification and recalculation

MO-D-213-07: RadShield: Semi- Automated Calculation of Air Kerma Rate and Barrier Thickness

Energy Technology Data Exchange (ETDEWEB)

DeLorenzo, M [Oklahoma University Health Sciences Center, Oklahoma City, OK (United States); Wu, D [University of Oklahoma Health Sciences Center, Oklahoma City, Ok (United States); Rutel, I [University of Oklahoma Health Science Center, Oklahoma City, OK (United States); Yang, K [Massachusetts General Hospital, Boston, MA (United States)

2015-06-15

Purpose: To develop the first Java-based semi-automated calculation program intended to aid professional radiation shielding design. Air-kerma rate and barrier thickness calculations are performed by implementing NCRP Report 147 formalism into a Graphical User Interface (GUI). The ultimate aim of this newly created software package is to reduce errors and improve radiographic and fluoroscopic room designs over manual approaches. Methods: Floor plans are first imported as images into the RadShield software program. These plans serve as templates for drawing barriers, occupied regions and x-ray tube locations. We have implemented sub-GUIs that allow the specification in regions and equipment for occupancy factors, design goals, number of patients, primary beam directions, source-to-patient distances and workload distributions. Once the user enters the above parameters, the program automatically calculates air-kerma rate at sampled points beyond all barriers. For each sample point, a corresponding minimum barrier thickness is calculated to meet the design goal. RadShield allows control over preshielding, sample point location and material types. Results: A functional GUI package was developed and tested. Examination of sample walls and source distributions yields a maximum percent difference of less than 0.1% between hand-calculated air-kerma rates and RadShield. Conclusion: The initial results demonstrated that RadShield calculates air-kerma rates and required barrier thicknesses with reliable accuracy and can be used to make radiation shielding design more efficient and accurate. This newly developed approach differs from conventional calculation methods in that it finds air-kerma rates and thickness requirements for many points outside the barriers, stores the information and selects the largest value needed to comply with NCRP Report 147 design goals. Floor plans, parameters, designs and reports can be saved and accessed later for modification and recalculation

THE CHALLENGE OF THE LARGEST STRUCTURES IN THE UNIVERSE TO COSMOLOGY

International Nuclear Information System (INIS)

Park, Changbom; Choi, Yun-Young; Kim, Sungsoo S.; Kim, Kap-Sung; Kim, Juhan; Gott III, J. Richard

2012-01-01

Large galaxy redshift surveys have long been used to constrain cosmological models and structure formation scenarios. In particular, the largest structures discovered observationally are thought to carry critical information on the amplitude of large-scale density fluctuations or homogeneity of the universe, and have often challenged the standard cosmological framework. The Sloan Great Wall (SGW) recently found in the Sloan Digital Sky Survey (SDSS) region casts doubt on the concordance cosmological model with a cosmological constant (i.e., the flat ΛCDM model). Here we show that the existence of the SGW is perfectly consistent with the ΛCDM model, a result that only our very large cosmological N-body simulation (the Horizon Run 2, HR2) could supply. In addition, we report on the discovery of a void complex in the SDSS much larger than the SGW, and show that such size of the largest void is also predicted in the ΛCDM paradigm. Our results demonstrate that an initially homogeneous isotropic universe with primordial Gaussian random phase density fluctuations growing in accordance with the general relativity can explain the richness and size of the observed large-scale structures in the SDSS. Using the HR2 simulation we predict that a future galaxy redshift survey about four times deeper or with 3 mag fainter limit than the SDSS should reveal a largest structure of bright galaxies about twice as big as the SGW.

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

Phenomena and characteristics of barrier river reaches in the middle and lower Yangtze River, China

Science.gov (United States)

You, Xingying; Tang, Jinwu

2017-06-01

Alluvial river self-adjustment describes the mechanism whereby a river that was originally in an equilibrium state of sediment transport encounters some disturbance that destroys the balance and results in responses such as riverbed deformation. A systematic study of historical and recent aerial photographs and topographic maps in the Middle and Lower Reaches of the Yangtze River (MLYR) shows that river self-adjustment has the distinguishing feature of transferring from upstream to downstream, which may affect flood safety, waterway morphology, bank stability, and aquatic environmental safety over relatively long reaches downstream. As a result, it is necessary to take measures to control or block this transfer. Using the relationship of the occurrence time of channel adjustments between the upstream and downstream, 34 single-thread river reaches in the MLYR were classified into four types: corresponding, basically corresponding, basically not corresponding, not corresponding. The latter two types, because of their ability to prevent upstream channel adjustment from transferring downstream, are called barrier river reaches in this study. Statistics indicate that barrier river reaches are generally single thread and slightly curved, with a narrow and deep cross-sectional morphology, and without flow deflecting nodes in the upper and middle parts of reaches. Moreover, in the MLYR, barrier river reaches have a hydrogeometric coefficient of {}1.2‱, a silty clay content of the concave bank {>}{9.5}%, and a median diameter of the bed sediment {>}{0.158} mm. The barrier river reach mechanism lies in that can effectively centralise the planimetric position of the main stream from different upstream directions, meaning that no matter how the upper channel adjusts, the main stream shows little change, providing relatively stable inflow conditions for the lower reaches. Regarding river regulation, it is necessary to optimise the benefits of barrier river reaches; long river

Evaluation of synthetic zeolite as engineering passive permeable reactive barrier

International Nuclear Information System (INIS)

Ibrahim, O.A.A.

2011-01-01

The presence of toxic pollutants in groundwater brings about significant changes in the properties of water resources and has to be avoided in order to preserve the environmental quality. Heavy metals are among the most dangerous inorganic water pollutants, that related to many anthropogenic sources and their compounds are extremely toxic. The treatment of contaminated groundwater is among the most difficult and expensive environmental problems. Over the past years, permeable reactive barriers have provided an increasingly important role in the passive insitu treatment of contaminated groundwater. There are a large number of materials that are able to immobilize contaminants by sorption, including granulated active carbon, zeolite, montmorillonite, peat, compost, sawdust, etc. Zeolite X is a synthetic counterpart of the naturally occurring mineral Faujasite. It has one of the largest cavities and cavity entrances of any known zeolites. The main aim of this work is to examine the possibility of using synthetic zeolite X as an engineering permeable reactive barrier to remove heavy metals from a contaminated groundwater. Within this context, the following investigations were carried out: 1. Review on the materials most commonly used as engineered permeable reactive barriers to identify the important features to be considered in the examination of the proposed permeable reactive barrier material (zeolite X). 2. Synthesis of zeolite X and characterization of the synthesized material using different techniques. 3. Batch tests were carried out to characterize the equilibrium and kinetic sorption properties of the synthesized zeolite X towards the concerned heavy metals; zinc and cadmium ions. 4. Column tests were also performed to determine the design factors for permeable reactive barrier against zinc and cadmium ions solutions.Breakthrough curves measured in such experiments used to determine the hydrodynamic dispersion coefficients for both metal ions. 5. Analytical

Functionally gradient materials for thermal barrier coatings in advanced gas turbine systems

Energy Technology Data Exchange (ETDEWEB)

Banovic, S.W.; Barmak, K.; Chan, H.M. [Lehigh Univ., Bethlehem, PA (United States)] [and others

1995-10-01

New designs for advanced gas turbine engines for power production are required to have higher operating temperatures in order to increase efficiency. However, elevated temperatures will increase the magnitude and severity of environmental degradation of critical turbine components (e.g. combustor parts, turbine blades, etc{hor_ellipsis}). To offset this problem, the usage of thermal barrier coatings (TBCs) has become popular by allowing an increase in maximum inlet temperatures for an operating engine. Although thermal barrier technology is over thirty years old, the principle failure mechanism is the spallation of the ceramic coating at or near the ceramic/bond coat interface. Therefore, it is desirable to develop a coating that combines the thermal barrier qualities of the ceramic layer and the corrosion protection by the metallic bond coat without the detrimental effects associated with the localization of the ceramic/metal interface to a single plane.

Barriers and Opportunities to Advancing Women in Leadership Roles in Vector Control: Perspectives from a Stakeholder Survey.

Science.gov (United States)

Hayden, Mary H; Barrett, Erika; Bernard, Guyah; Toko, Eunice N; Agawo, Maurice; Okello, Amanda M; Gunn, Jayleen K L; Ernst, Kacey C

2018-05-01

Increasing the active participation of professional women in vector control (VC) activities may help promote greater gender equity in the workplace and reduce the burden of vector-borne diseases. This stakeholder survey examined the current roles and perspective of professionals employed in the VC sector in Kenya, Indonesia, India, and other countries. The largest barriers that women face in pursuing leadership roles in the VC sector include lack of awareness of career opportunities, limitations based on cultural norms, and the belief that VC is men's work. These barriers could be addressed through improving education and recruitment campaigns, as well as supporting higher education and mentoring programs. Females were almost six times more likely to be encouraged to pursue leadership positions in their organization compared with male respondents (odds ratio = 5.9, P > 0.03, 95% confidence interval: 1.19, 29.42). These findings suggest that once women are recruited into the VC workforce, they face minimal discrimination and have increased leadership opportunities.

Prospects for the synthesis of large single-crystal diamonds

International Nuclear Information System (INIS)

Khmelnitskiy, R A

2015-01-01

The unique properties of diamond have stimulated the study of and search for its applications in many fields, including optics, optoelectronics, electronics, biology, and electrochemistry. Whereas chemical vapor deposition allows the growth of polycrystalline diamond plates more than 200 mm in diameter, most current diamond application technologies require large-size (25 mm and more) single-crystal diamond substrates or films suitable for the photolithography process. This is quite a challenge, because the largest diamond crystals currently available are 10 mm or less in size. This review examines three promising approaches to fabricating large-size diamond single crystals: growing large-size single crystals, the deposition of heteroepitaxial diamond films on single-crystal substrates, and the preparation of composite diamond substrates. (reviews of topical problems)

Long-term outcomes after allogeneic hematopoietic stem cell transplantation for metachromatic leukodystrophy: the largest single-institution cohort report

OpenAIRE

Boucher, Alexander A.; Miller, Weston; Shanley, Ryan; Ziegler, Richard; Lund, Troy; Raymond, Gerald; Orchard, Paul J.

2015-01-01

Background Metachromatic Leukodystrophy (MLD) is a rare, fatal demyelinating disorder with limited treatment options. Published outcomes after hematopoietic stem cell transplantation (HSCT) are scant and mixed. We report survival and function following HSCT for a large, single-center MLD cohort. Methods Transplant-related data, survival and serial measures (brain MRI, nerve conduction velocity (NCV), neurologic and neuropsychology evaluations) were reviewed. When possible, parental interviews...

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

The effects of moisture on LiD single crystals studied by temperature-programmed decomposition

International Nuclear Information System (INIS)

Dinh, L.N.; Cecala, C.M.; Leckey, J.H.; Balooch, M.

2001-01-01

Temperature-programmed decomposition (TPD) technique was performed on LiOH powders and LiD single crystals previously exposed to different moisture levels. Our results show that the LiOH decomposition process is rate-limited by an inward moving reaction front mechanism with an activation energy barrier of ∼122-149 kJ/mol. The LiOH structure is stable even if kept at 320 K. However, LiOH structures formed on the surface of LiD single crystals during moisture exposure at low dosages may have multiple activation energy barriers, some of which may be much lower than 122 kJ/mol. The rate-limiting mechanism for the decomposition of LiOH structures with reduced activation energy barriers is consistent with a unimolecular nucleation model. We attribute the lowering of the activation energy barrier for the LiOH decomposition to the existence of sub-stoichiometric Li(OH) x with x 2 O formation is observed. The release of H 2 O molecules from LiOH · H 2 O structure has small activation energy barriers in the range of 48-69 kJ/mol and follows a unimolecular nucleation process. The loosely bonded H 2 O molecules in the LiOH · H 2 O structure can be easily pumped away at room temperature in a reasonable amount of time. Our experiments also suggest that handling LiD single crystals at an elevated temperature of 340 K or more reduces the growth rate of LiOH and LiOH · H 2 O significantly

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

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

Energy Technology Data Exchange (ETDEWEB)

Jensen, O.M.

2004-07-01

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

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.

Mass balance of Greenland's three largest outlet glaciers - 2000–2010

NARCIS (Netherlands)

Howat, I.M.; Ahn, Y.; Joughin, I.; van den Broeke, M.R.; Lenaerts, J.T.M.; Smith, B.

2011-01-01

Acceleration of Greenland's three largest outlet glaciers, Helheim, Kangerdlugssuaq and Jakobshavn Isbræ, accounted for a substantial portion of the ice sheet's mass loss over the past decade. Rapid changes in their discharge, however, make their cumulative mass-change uncertain. We derive monthly

Data analysis strategies for the characterization of normal: superconductor point contacts by barrier strength parameter

Science.gov (United States)

Smith, Charles W.; Reinertson, Randal C.; Dolan, P. J., Jr.

1993-05-01

The theoretical description by Blonder, Tinkham, and Klapwijk [Phys. Rev. B 25, 4515 (1982)] of the I-V curves of normal: superconductor point contacts encompasses a broad range of experimental behavior, from the tunnel junction case, on the one hand, to the clean metallic microconstriction limit on the other. The theory characterizes point contacts in terms of a single parameter, the barrier strength. The differential conductance of a point contact, at zero bias, as a function of temperature, offers a direct experimental method by which the barrier strength parameter can be evaluated. In view of the full range of phenomena incorporated by this theory, we suggest several different strategies for the evaluation of the barrier strength parameter from data in the low and intermediate barrier strength regimes and for measurements in the low temperature (near T=0 K) and high temperature (near T=Tc) limits.

Role of structural barriers in the in vitro bioaccessibility of anthocyanins in comparison with carotenoids.

Science.gov (United States)

Carrillo, Celia; Buvé, Carolien; Panozzo, Agnese; Grauwet, Tara; Hendrickx, Marc

2017-07-15

Although natural structural barriers are factors limiting nutrient bioaccessibility, their specific role in anthocyanin bioaccessibility is still unknown. To better understand how natural barriers govern bioactive compound bioaccessibility, an experimental approach comparing anthocyanins and carotenoids was designed, using a single plant matrix. Initial results revealed increased anthocyanin bioaccessibility in masticated black carrot. To explain this observation, samples with increasing levels of bioencapsulation (free-compound, homogenized-puree, puree) were examined. While carotenoid bioaccessibility was inversely proportional to the level of bioencapsulation, barrier disruption did not increase anthocyanin bioaccessibility. This means that mechanical processing is of particular importance in the case of carotenoid bioaccessibility. While micelle incorporation is the limiting factor for carotenoid bioaccessibility, anthocyanin degradation under alkaline conditions in the gastrointestinal tract dominates. In the absence of structural barriers, anthocyanin bioaccessibility is greater than that of carotenoids. Copyright © 2017 Elsevier Ltd. All rights reserved.

New evidence of an early Pridoli barrier reef in the southern part of the Baltic Silurian basin based on three-dimensional seismic survey, Lithuania

Directory of Open Access Journals (Sweden)

Donatas Kaminskas

2015-02-01

Full Text Available Reefs and a barrier reef have been newly identified and mapped by three-dimensional (3D seismic survey in Lithuania. Seismic data analysis has allowed the size and geometry of these reefs to be determined. The largest reefs occur at Pavasaris and South Bliudziai. They have a similar shape and are about 1.5 km long and 1 km wide. A circle-shaped smaller patch reef at North Bliudziai is 1 km in diameter. The overall heights of the studied structures do not exceed 30–40 m. The reefs consist of coarse-grained bioclastic stromatoporoid limestone. A barrier reef rising structurally from SW to NE was established in the west of the mapped area. The stratigraphic position (early Minija Regional Stage and lateral distribution of the barrier reef suggest it started to form earlier than the group of patch reefs. The development of patch reefs was related to the transgression of the Silurian Baltic basin.

Sub-barrier quasifission in heavy element formation reactions with deformed actinide target nuclei

Science.gov (United States)

Hinde, D. J.; Jeung, D. Y.; Prasad, E.; Wakhle, A.; Dasgupta, M.; Evers, M.; Luong, D. H.; du Rietz, R.; Simenel, C.; Simpson, E. C.; Williams, E.

2018-02-01

Background: The formation of superheavy elements (SHEs) by fusion of two massive nuclei is severely inhibited by the competing quasifission process. Low excitation energies favor SHE survival against fusion-fission competition. In "cold" fusion with spherical target nuclei near 208Pb, SHE yields are largest at beam energies significantly below the average capture barrier. In "hot" fusion with statically deformed actinide nuclei, this is not the case. Here the elongated deformation-aligned configurations in sub-barrier capture reactions inhibits fusion (formation of a compact compound nucleus), instead favoring rapid reseparation through quasifission. Purpose: To determine the probabilities of fast and slow quasifission in reactions with prolate statically deformed actinide nuclei, through measurement and quantitative analysis of the dependence of quasifission characteristics at beam energies spanning the average capture barrier energy. Methods: The Australian National University Heavy Ion Accelerator Facility and CUBE fission spectrometer have been used to measure fission and quasifission mass and angle distributions for reactions with projectiles from C to S, bombarding Th and U target nuclei. Results: Mass-asymmetric quasifission occurring on a fast time scale, associated with collisions with the tips of the prolate actinide nuclei, shows a rapid increase in probability with increasing projectile charge, the transition being centered around projectile atomic number ZP=14 . For mass-symmetric fission events, deviations of angular anisotropies from expectations for fusion fission, indicating a component of slower quasifission, suggest a similar transition, but centered around ZP˜8 . Conclusions: Collisions with the tips of statically deformed prolate actinide nuclei show evidence for two distinct quasifission processes of different time scales. Their probabilities both increase rapidly with the projectile charge. The probability of fusion can be severely

The Single-Phase ProtoDUNE Technical Design Report

Energy Technology Data Exchange (ETDEWEB)

Abi, B. [Univ. of Padova (Italy); et al.

2017-06-21

ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in its own right. With a total liquid argon (LAr) mass of 0.77 kt, it represents the largest monolithic single-phase LArTPC detector to be built to date. It's technical design is given in this report.

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

Dielectric barrier discharges: progress on plasma sources and on the understanding of regimes and single filaments

Science.gov (United States)

Brandenburg, Ronny

2017-05-01

Dielectric barrier discharges (DBDs) are plasmas generated in configurations with an insulating (dielectric) material between the electrodes which is responsible for a self-pulsing operation. DBDs are a typical example of nonthermal atmospheric or normal pressure gas discharges. Initially used for the generation of ozone, they have opened up many other fields of application. Therefore DBDs are a relevant tool in current plasma technology as well as an object for fundamental studies. Another motivation for further research is the fact that so-called partial discharges in insulated high voltage systems are special types of DBDs. The breakdown processes, the formation of structures, and the role of surface processes are currently under investigation. This review is intended to give an update to the already existing literature on DBDs considering the research and development within the last two decades. The main principles and different modes of discharge generation are summarized. A collection of known as well as special electrode configurations and reactor designs will be presented. This shall demonstrate the different and broad possibilities, but also the similarities and common aspects of devices for different fields of applications explored within the last years. The main part is devoted to the progress on the investigation of different aspects of breakdown and plasma formation with the focus on single filaments or microdischarges. This includes a summary of the current knowledge on the electrical characterization of filamentary DBDs. In particular, the recent new insights on the elementary volume and surface memory mechanisms in these discharges will be discussed. An outlook for the forthcoming challenges on research and development will be given.

Perspectives about family meals from single-headed and dual-headed households: a qualitative analysis.

Science.gov (United States)

Berge, Jerica M; Hoppmann, Caroline; Hanson, Carrie; Neumark-Sztainer, Dianne

2013-12-01

Cross-sectional and longitudinal research has shown that family meals are protective for adolescent healthful eating behaviors. However, little is known about what parents think of these findings and whether parents from single- vs dual-headed households have differing perspectives about the findings. In addition, parents' perspectives regarding barriers to applying the findings on family meals in their own homes and suggestions for more widespread adoption of the findings are unknown. The current study aimed to identify single- and dual-headed household parents' perspectives regarding the research findings on family meals, barriers to applying the findings in their own homes, and suggestions for helping families have more family meals. The current qualitative study included 59 parents who participated in substudy of two linked multilevel studies-EAT 2010 (Eating and Activity in Teens) and Families and Eating and Activity in Teens (F-EAT). Parents (91.5% female) were racially/ethnically and socioeconomically diverse. Data were analyzed using a grounded theory approach. Results from the current study suggest that parents from both single- and dual-headed households have similar perspectives regarding why family meals are protective for healthful eating habits for adolescents (eg, provides structure/routine, opportunities for communication, connection), but provide similar and different reasons for barriers to family meals (eg, single-headed=cost vs dual-headed=lack of creativity) and ideas and suggestions for how to increase the frequency of family meals (eg, single-headed=give fewer options vs dual-headed=include children in the meal preparation). Findings can help inform public health intervention researchers and providers who work with adolescents and their families to understand how to approach discussions regarding reasons for having family meals, barriers to carrying out family meals, and ways to increase family meals depending on family structure. Copyright �

Design of engineered sorbent barriers

International Nuclear Information System (INIS)

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

1988-01-01

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

Barrier Data Base user's guide

International Nuclear Information System (INIS)

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

1977-06-01

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

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

Single Black Working Mothers' Perceptions: The Journey to Achieve Leadership Positions

Science.gov (United States)

Raglin, Sherrell

2017-01-01

Single Black working mothers faced significant challenges in achieving high-level or senior-level leadership positions. The purpose of this qualitative narrative study was to collect, analyze and code the stories told by 10 participants to understand the perceptions and insights of the challenges and barriers single Black working mothers faced in…

Health Insurance Premium Increases for the 5 Largest School Districts in the United States, 2004–2008

Science.gov (United States)

Cantillo, John R.

2010-01-01

Background Local school districts are often one of the largest, if not the largest, employers in their respective communities. Like many large employers, school districts offer health insurance to their employees. There is a lack of information about the rate of health insurance premiums in US school districts relative to other employers. Objective To assess the change in the costs of healthcare insurance in the 5 largest public school districts in the United States, between 2004 and 2008, as representative of large public employers in the country. Methods Data for this study were drawn exclusively from a survey sent to the 5 largest public school districts in the United States. The survey requested responses on 3 data elements for each benefit plan offered from 2004 through 2008; these included enrollment, employee costs, and employer costs. Results The premium growth for the 5 largest school districts has slowed down and is consistent with other purchasers—Kaiser/Health Research & Educational Trust and the Federal Employee Health Benefit Program. The average increase in health insurance premium for the schools was 5.9% in 2008, and the average annual growth rate over the study period was 7.5%. For family coverage, these schools provide the most generous employer contribution (80.8%) compared with the employer contribution reported by other employers (73.5%) for 2008. Conclusions Often the largest employers in their communities, school districts demonstrate a commitment to provide choice of benefits and affordability for employees and their families. Despite constraints typical of public employers, the 5 largest school districts in the United States have decelerated in premium growth consistent with other purchasers, albeit at a slower pace. PMID:25126311

Noble internal transport barriers and radial subdiffusion of toroidal magnetic lines

Energy Technology Data Exchange (ETDEWEB)

Misguich, J.H.; Reuss, J.D. [Association Euratom-CEA sur la Fusion, CEA/DSM/DRFC, 13 - Saint Paul lez Durance (France); Constantinescu, D.; Steinbrecher, G. [Association Euratom-N.A.S.T.I., Dept. of Physics, University of Craiova (Romania); Vlad, M.; Spineanu, F. [Association Euratom-N.A.S.T.I., National Institute of Laser, Plasma and Radiation Physics, Bucharest (Romania); Weyssow, B.; Balescu, R. [Association Euratom-Etat Belge sur la Fusion, Universite Libre de Bruxelles (Belgium)

2002-02-01

Internal transport barriers (ITB's) observed in tokamaks are described by a purely magnetic approach. Magnetic line motion in toroidal geometry with broken magnetic surfaces is studied from a previously derived Hamiltonian map in situation of incomplete chaos. This appears to reproduce in a realistic way the main features of a tokamak, for a given safety factor profile and in terms of a single parameter L representing the amplitude of the magnetic perturbation. New results are given concerning the Shafranov shift as function of L. For small values of L, closed magnetic surfaces exist (KAM tori) and island chains begin to appear on rational surfaces for higher values of L, with chaotic zones around hyperbolic points, as expected. Single trajectories of magnetic line motion indicate the persistence of a central protected plasma core, surrounded by a chaotic shell enclosed in a double-sided transport barrier. Magnetic lines which succeed to escape across this barrier begin to wander in a wide chaotic sea extending up to a very robust barrier (as long as L{<=}1). For values of L{>=}1, above the escape threshold, most magnetic lines succeed to escape out of the external barrier which has become a permeable Cantorus. Statistical analysis of a large number of trajectories, representing the evolution of a bunch of magnetic lines, indicate that the flux variable {psi} asymptotically grows in a diffuse manner as (L{sup 2}t) with a L{sup 2} scaling as expected, but that the average radial position r{sub m}(t) asymptotically grows as (L{sup 2}t){sup 1/4} while the mean square displacement around this average radius asymptotically grows in a sub-diffusive manner as (L{sup 2}t){sup 1/2}. This result shows the slower dispersion in the present incomplete chaotic regime, which is different from the usual quasilinear diffusion in completely chaotic situations. For physical times t{sub {phi}} of the order of the escape time defined by x{sub m}(t{sub {phi}}) {approx}1, the motion

Noble internal transport barriers and radial subdiffusion of toroidal magnetic lines

International Nuclear Information System (INIS)

Misguich, J.H.; Reuss, J.D.; Constantinescu, D.; Steinbrecher, G.; Vlad, M.; Spineanu, F.; Weyssow, B.; Balescu, R.

2002-02-01

Internal transport barriers (ITB's) observed in tokamaks are described by a purely magnetic approach. Magnetic line motion in toroidal geometry with broken magnetic surfaces is studied from a previously derived Hamiltonian map in situation of incomplete chaos. This appears to reproduce in a realistic way the main features of a tokamak, for a given safety factor profile and in terms of a single parameter L representing the amplitude of the magnetic perturbation. New results are given concerning the Shafranov shift as function of L. For small values of L, closed magnetic surfaces exist (KAM tori) and island chains begin to appear on rational surfaces for higher values of L, with chaotic zones around hyperbolic points, as expected. Single trajectories of magnetic line motion indicate the persistence of a central protected plasma core, surrounded by a chaotic shell enclosed in a double-sided transport barrier. Magnetic lines which succeed to escape across this barrier begin to wander in a wide chaotic sea extending up to a very robust barrier (as long as L≤1). For values of L≥1, above the escape threshold, most magnetic lines succeed to escape out of the external barrier which has become a permeable Cantorus. Statistical analysis of a large number of trajectories, representing the evolution of a bunch of magnetic lines, indicate that the flux variable ψ asymptotically grows in a diffuse manner as (L 2 t) with a L 2 scaling as expected, but that the average radial position r m (t) asymptotically grows as (L 2 t) 1/4 while the mean square displacement around this average radius asymptotically grows in a sub-diffusive manner as (L 2 t) 1/2 . This result shows the slower dispersion in the present incomplete chaotic regime, which is different from the usual quasilinear diffusion in completely chaotic situations. For physical times t φ of the order of the escape time defined by x m (t φ ) ∼1, the motion appears to be super-diffusive, however, but less dangerous than

Design of engineered sorbent barriers

International Nuclear Information System (INIS)

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

1988-08-01

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

Technological barriers to the growth of the export potential of Russian grain industry

Directory of Open Access Journals (Sweden)

O. A. Eremchenko

2017-01-01

Full Text Available Russia is the world's largest wheat exporter. The sales volume on foreign markets in 2015 amounted to $3.9 billion, or 10.1% of global exports. By the end of 2015, the volume of exports of agricultural products exceeded revenues from sales of arms in foreign markets. However, in dollar terms, wheat exports correspond to only a fifth place in the world. The article analyzes the reasons for a significant gap in the volume of exports and revenue, barriers to the development of export of agricultural deep processed products. The assumption is made that the development of technologies for deep processing of grain crops will increase the share of exports of Russian products with high added value.

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

Considering dominance in reduced single-step genomic evaluations.

Science.gov (United States)

Ertl, J; Edel, C; Pimentel, E C G; Emmerling, R; Götz, K-U

2018-06-01

Single-step models including dominance can be an enormous computational task and can even be prohibitive for practical application. In this study, we try to answer the question whether a reduced single-step model is able to estimate breeding values of bulls and breeding values, dominance deviations and total genetic values of cows with acceptable quality. Genetic values and phenotypes were simulated (500 repetitions) for a small Fleckvieh pedigree consisting of 371 bulls (180 thereof genotyped) and 553 cows (40 thereof genotyped). This pedigree was virtually extended for 2,407 non-genotyped daughters. Genetic values were estimated with the single-step model and with different reduced single-step models. Including more relatives of genotyped cows in the reduced single-step model resulted in a better agreement of results with the single-step model. Accuracies of genetic values were largest with single-step and smallest with reduced single-step when only the cows genotyped were modelled. The results indicate that a reduced single-step model is suitable to estimate breeding values of bulls and breeding values, dominance deviations and total genetic values of cows with acceptable quality. © 2018 Blackwell Verlag GmbH.

The largest glitch observed in the Crab pulsar

Science.gov (United States)

Shaw, B.; Lyne, A. G.; Stappers, B. W.; Weltevrede, P.; Bassa, C. G.; Lien, A. Y.; Mickaliger, M. B.; Breton, R. P.; Jordan, C. A.; Keith, M. J.; Krimm, H. A.

2018-05-01

We have observed a large glitch in the Crab pulsar (PSR B0531+21). The glitch occurred around MJD 58064 (2017 November 8) when the pulsar underwent an increase in the rotation rate of Δν = 1.530 × 10-5 Hz, corresponding to a fractional increase of Δν/ν = 0.516 × 10-6 making this event the largest glitch ever observed in this source. Due to our high-cadence and long-dwell time observations of the Crab pulsar we are able to partially resolve a fraction of the total spin-up of the star. This delayed spin-up occurred over a timescale of ˜1.7 days and is similar to the behaviour seen in the 1989 and 1996 large Crab pulsar glitches. The spin-down rate also increased at the glitch epoch by Δ \\dot{ν } / \\dot{ν } = 7 × 10^{-3}. In addition to being the largest such event observed in the Crab, the glitch occurred after the longest period of glitch inactivity since at least 1984 and we discuss a possible relationship between glitch size and waiting time. No changes to the shape of the pulse profile were observed near the glitch epoch at 610 MHz or 1520 MHz, nor did we identify any changes in the X-ray flux from the pulsar. The long-term recovery from the glitch continues to progress as \\dot{ν } slowly rises towards pre-glitch values. In line with other large Crab glitches, we expect there to be a persistent change to \\dot{ν }. We continue to monitor the long-term recovery with frequent, high quality observations.

Researchers propose single grade rule for evaluating hardwood pallet cants

Science.gov (United States)

Hal Mitchell; Marshall White; Philip Araman; Peter Hamner

2008-01-01

In "price taker" markets, successful businesses are the low cost producers, and pallet manufacturers are no exception. The single largest cost component of pallet manufacturing is raw material costs. Cants and lumber typically account for over 60% of operating costs. In the last three decades, cants have replaced lumber as the primary raw...

Effect of barrier height on friction behavior of the semiconductors silicon and gallium arsenide in contact with pure metals

Science.gov (United States)

Mishina, H.; Buckley, D. H.

1984-01-01

Friction experiments were conducted for the semiconductors silicon and gallium arsenide in contact with pure metals. Polycrystalline titanium, tantalum, nickel, palladium, and platinum were made to contact a single crystal silicon (111) surface. Indium, nickel, copper, and silver were made to contact a single crystal gallium arsenide (100) surface. Sliding was conducted both in room air and in a vacuum of 10 to the minus 9th power torr. The friction of semiconductors in contact with metals depended on a Schottky barrier height formed at the metal semiconductor interface. Metals with a higher barrier height on semiconductors gave lower friction. The effect of the barrier height on friction behavior for argon sputtered cleaned surfaces in vacuum was more specific than that for the surfaces containing films in room air. With a silicon surface sliding on titanium, many silicon particles back transferred. In contrast, a large quantity of indium transferred to the gallium arsenide surface.

Fission barriers of two odd-neutron heavy nuclei

International Nuclear Information System (INIS)

Koh, Meng-Hock; Bonneau, L.; Nhan Hao, T. V.; Duc, Dao Duy; Quentin, P.

2015-01-01

The fission barriers of two odd-neutron heavy odd nuclei,namely the 235 U and 239 Pu isotopes have been calculated within a self-consistent Hartree-Fock-plus-BCS approach with blocking. A Skyrme nucleon-nucleon effective interaction has been used together with a seniority force to describe pairing correlations. A full account of the genuine time-reversal symmetry breaking due to the presence of an unpaired nucleon has been incorporated at the mean field level. The SIII and SkM* parametrizations of the Skyrme interaction have been retained as well as for a part a newer parametrization, SLy5*. The seniority force parameters have been fitted to reproduce experimental odd-even mass differences in the actinide region. To assess the relevance of our calculated fission barrier distribution (as a function of the quantum numbers), we have studied the quality of our results with respect to the spectroscopy of band heads (for configurations deemed to be a pure single particle character) in the ground and fission isomeric states. Fission barriers of the considered odd nuclei have been compared with what is obtained for their even-even neighbouring isotopes (namely 234 U and 236 U, 238 Pu and 240 Pu respectively) to determine the so-called specialization energies. Various corrections and associated uncertainties have been discussed in order to compare our results with available data

Homogeneous dielectric barrier discharges in atmospheric air and its influencing factor

Science.gov (United States)

Ran, Junxia; Li, Caixia; Ma, Dong; Luo, Haiyun; Li, Xiaowei

2018-03-01

The stable homogeneous dielectric barrier discharge (DBD) is obtained in atmospheric 2-3 mm air gap. It is generated using center frequency 1 kHz high voltage power supply between two plane parallel electrodes with specific alumina ceramic plates as the dielectric barriers. The discharge characteristics are studied by a measurement of its electrical discharge parameters and observation of its light emission phenomena. The results show that a large single current pulse of about 200 μs duration appearing in each voltage pulse, and its light emission is radially homogeneous and covers the entire surface of the two electrodes. The homogeneous discharge generated is a Townsend discharge during discharge. The influences of applied barrier, its thickness, and surface roughness on the transition of discharge modes are studied. The results show that it is difficult to produce a homogeneous discharge using smooth plates or alumina plate surface roughness Ra material, dielectric thickness, and dielectric surface roughness should be used, and proper applied voltage amplitude and frequency should also be used.

Longevity in Calumma parsonii, the World's largest chameleon.

Science.gov (United States)

Tessa, Giulia; Glaw, Frank; Andreone, Franco

2017-03-01

Large body size of ectothermic species can be correlated with high life expectancy. We assessed the longevity of the World's largest chameleon, the Parson's chameleon Calumma parsonii from Madagascar by using skeletochronology of phalanges taken from preserved specimens held in European natural history museums. Due to the high bone resorption we can provide only the minimum age of each specimen. The highest minimum age detected was nine years for a male and eight years for a female, confirming that this species is considerably long living among chameleons. Our data also show a strong correlation between snout-vent length and estimated age. Copyright © 2017 Elsevier Inc. All rights reserved.

Enhancing the effective energy barrier of a Dy(III) SMM using a bridged diamagnetic Zn(II) ion.

Science.gov (United States)

Upadhyay, Apoorva; Singh, Saurabh Kumar; Das, Chinmoy; Mondol, Ranajit; Langley, Stuart K; Murray, Keith S; Rajaraman, Gopalan; Shanmugam, Maheswaran

2014-08-18

Field induced single-molecule-magnet behaviour is observed for both a heterodinuclear [ZnDy(L(-))2](3+) complex (1) and a mononuclear [Dy(HL)2](3+) complex (2), with effective energy barriers of 83 cm(-1) and 16 cm(-1), respectively. Insights into the relaxation mechanism(s) and barrier heights are provided via ab initio and DFT calculations. Our findings reveal an interesting observation that the U(eff) of SMMs can be enhanced by incorporating diamagnetic metal ions.

Study on characteristics of high frequency dielectric barrier discharge for the removal of organic pollutant adsorbed on activated carbon

Energy Technology Data Exchange (ETDEWEB)

Qu, G.Z.; Li, G.F. [Dalian Univ. of Technology, Dalian (China). Inst. of Electrostatics and Special Power; Li, J.; Lu, N.; Wu, Y.; Li, D. [Dalian Univ. of Technology, Dalian (China). Inst. of Electrostatics and Special Power; Key Lab of Industrial Ecology and Environmental Engineering, Ministry of Education, Dalian (China)

2010-07-01

Advanced oxidation technologies such as photocatalysis, electrochemical degradation, Fenton oxidation, hydrogen peroxide oxidation, and plasma oxidation are increasingly being used to degrade refractory biodegradable organic contaminants. The plasma oxidation method has the advantage of direct in situ production of multiple types of high-reactive chemical species, including molecules and radicals that facilitate the degradation reaction. In addition, plasma oxidation does not produce any secondary pollution. Compared to other plasma technologies, the dielectric barrier discharge (DBD) plasma has been considered as a promising technology for removing toxic compounds because of its stability and its treatability property of biologically recalcitrant compounds in wastewater. However, the energy efficiency of DBD requires improvement for economic reasons. This paper reported on an experimental study that investigated the electrical characteristics of a parallel plate DBD reactor using a high frequency power supply for the removal of pentachlorophenol (PCP) adsorbed on activated carbon (AC). This study examined the effects of AC with different mass on discharge characteristics and compared the voltage and current waveforms, and discharge images of DBD reactors with different dielectric configurations. When the DBD reactor filled with AC, the applied voltage of discharge decreased regardless of the DBD reactor configuration in terms of having a single barrier or two barriers. The discharge characteristics had no significant change with AC mass increasing. The discharge images and current waveforms showed that DBD reactor configuration consisting of two dielectrics is more homogeneous and stable than the one consisting of a single dielectric. Under the same electric field condition, the degradation efficiency of PCP in two barriers reactor is higher than that in single barrier reactor. It was concluded that the findings from this study may be instrumental in treating

Barrier cell sheath formation

International Nuclear Information System (INIS)

Kesner, J.

1980-04-01

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

A radio-frequency single-electron transistor based on an InAs/InP heterostructure nanowire

DEFF Research Database (Denmark)

Nilsson, Henrik A.; Duty, Tim; Abay, Simon

2008-01-01

We demonstrate radio frequency single-electron transistors fabricated from epitaxially grown InAs/InP heterostructure nanowires. Two sets of double-barrier wires with different barrier thicknesses were grown. The wires were suspended 15 nm above a metal gate electrode. Electrical measurements...... on a high-resistance nanowire showed regularly spaced Coulomb oscillations at a gate voltage from −0.5 to at least 1.8 V. The charge sensitivity was measured to 32 µerms Hz−1/2 at 1.5 K. A low-resistance single-electron transistor showed regularly spaced oscillations only in a small gate-voltage region just...

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).

Perceived exercise barriers explain exercise participation in Australian women treated for breast cancer better than perceived exercise benefits.

Science.gov (United States)

Gho, Sheridan A; Munro, Bridget J; Jones, Sandra C; Steele, Julie R

2014-12-01

This study aimed to determine the effect of perceived exercise benefits and barriers on exercise levels among women who have been treated for breast cancer and have not participated in a formal exercise intervention. This was an anonymous, national, online cross-sectional survey study. Four hundred thirty-two women treated for breast cancer completed an online survey covering their treatment and demographic background, current exercise levels, and perceived exercise benefits and barriers. Each perceived benefit and barrier was considered in a binary logistic regression against reported exercise levels to ascertain significant relationships and associative values (odds ratio [OR]). Agreement with 16 out of 19 exercise barriers was significantly related to being more likely to report insufficient exercise levels, whereas agreement with 6 out of 15 exercise benefits was significantly related to being less likely to report insufficient levels of exercise. Feeling too weak, lacking self-discipline, and not making exercise a priority were the barriers with the largest association to insufficient exercise levels (OR=10.97, 95% confidence interval [CI]=3.90, 30.86; OR=8.12, 95% CI=4.73, 13.93; and OR=7.43, 95% CI=3.72, 14.83, respectively). Conversely, exercise enjoyment, improved feelings of well-being, and decreased feelings of stress and tension were the top 3 benefits associated with being less likely to have insufficient exercise levels (OR=0.21, 95% CI=0.11, 0.39; OR=0.21, 95% CI=0.07, 0.63; and OR=0.31, 95% CI=0.15, 0.63, respectively). Self-reported data measures were used to collect exercise data. Targeting exercise barriers specific to women treated for breast cancer may improve exercise participation levels in this cohort. Awareness of the impact of exercise barriers identified in the present study will enable physical therapists to better plan exercise interventions that support all women treated for breast cancer. © 2014 American Physical Therapy Association.

Protein Homeostasis Imposes a Barrier on Functional Integration of Horizontally Transferred Genes in Bacteria.

Science.gov (United States)

Bershtein, Shimon; Serohijos, Adrian W R; Bhattacharyya, Sanchari; Manhart, Michael; Choi, Jeong-Mo; Mu, Wanmeng; Zhou, Jingwen; Shakhnovich, Eugene I

2015-10-01

Horizontal gene transfer (HGT) plays a central role in bacterial evolution, yet the molecular and cellular constraints on functional integration of the foreign genes are poorly understood. Here we performed inter-species replacement of the chromosomal folA gene, encoding an essential metabolic enzyme dihydrofolate reductase (DHFR), with orthologs from 35 other mesophilic bacteria. The orthologous inter-species replacements caused a marked drop (in the range 10-90%) in bacterial growth rate despite the fact that most orthologous DHFRs are as stable as E.coli DHFR at 37°C and are more catalytically active than E. coli DHFR. Although phylogenetic distance between E. coli and orthologous DHFRs as well as their individual molecular properties correlate poorly with growth rates, the product of the intracellular DHFR abundance and catalytic activity (kcat/KM), correlates strongly with growth rates, indicating that the drop in DHFR abundance constitutes the major fitness barrier to HGT. Serial propagation of the orthologous strains for ~600 generations dramatically improved growth rates by largely alleviating the fitness barriers. Whole genome sequencing and global proteome quantification revealed that the evolved strains with the largest fitness improvements have accumulated mutations that inactivated the ATP-dependent Lon protease, causing an increase in the intracellular DHFR abundance. In one case DHFR abundance increased further due to mutations accumulated in folA promoter, but only after the lon inactivating mutations were fixed in the population. Thus, by apparently distinguishing between self and non-self proteins, protein homeostasis imposes an immediate and global barrier to the functional integration of foreign genes by decreasing the intracellular abundance of their products. Once this barrier is alleviated, more fine-tuned evolution occurs to adjust the function/expression of the transferred proteins to the constraints imposed by the intracellular

Protein Homeostasis Imposes a Barrier on Functional Integration of Horizontally Transferred Genes in Bacteria.

Directory of Open Access Journals (Sweden)

Shimon Bershtein

2015-10-01

Full Text Available Horizontal gene transfer (HGT plays a central role in bacterial evolution, yet the molecular and cellular constraints on functional integration of the foreign genes are poorly understood. Here we performed inter-species replacement of the chromosomal folA gene, encoding an essential metabolic enzyme dihydrofolate reductase (DHFR, with orthologs from 35 other mesophilic bacteria. The orthologous inter-species replacements caused a marked drop (in the range 10-90% in bacterial growth rate despite the fact that most orthologous DHFRs are as stable as E.coli DHFR at 37°C and are more catalytically active than E. coli DHFR. Although phylogenetic distance between E. coli and orthologous DHFRs as well as their individual molecular properties correlate poorly with growth rates, the product of the intracellular DHFR abundance and catalytic activity (kcat/KM, correlates strongly with growth rates, indicating that the drop in DHFR abundance constitutes the major fitness barrier to HGT. Serial propagation of the orthologous strains for ~600 generations dramatically improved growth rates by largely alleviating the fitness barriers. Whole genome sequencing and global proteome quantification revealed that the evolved strains with the largest fitness improvements have accumulated mutations that inactivated the ATP-dependent Lon protease, causing an increase in the intracellular DHFR abundance. In one case DHFR abundance increased further due to mutations accumulated in folA promoter, but only after the lon inactivating mutations were fixed in the population. Thus, by apparently distinguishing between self and non-self proteins, protein homeostasis imposes an immediate and global barrier to the functional integration of foreign genes by decreasing the intracellular abundance of their products. Once this barrier is alleviated, more fine-tuned evolution occurs to adjust the function/expression of the transferred proteins to the constraints imposed by the

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

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.

Barriers against psychosocial communication: oncologists' perceptions.

Science.gov (United States)

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

2013-10-20

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

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

Directory of Open Access Journals (Sweden)

C Lehner

2016-05-01

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

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

Analytic approximation to the largest eigenvalue distribution of a white Wishart matrix

CSIR Research Space (South Africa)

Vlok, JD

2012-08-14

Full Text Available offers largely simplified computation and provides statistics such as the mean value and region of support of the largest eigenvalue distribution. Numeric results from the literature are compared with the approximation and Monte Carlo simulation results...

Safety barriers on oil and gas platforms. Means to prevent hydrocarbon releases

Energy Technology Data Exchange (ETDEWEB)

Sklet, Snorre

2005-12-15

The main objective of the PhD project has been to develop concepts and methods that can be used to define, illustrate, analyse, and improve safety barriers in the operational phase of offshore oil and gas production platforms. The main contributions of this thesis are; Clarification of the term safety barrier with respect to definitions, classification, and relevant attributes for analysis of barrier performance Development and discussion of a representative set of hydrocarbon release scenarios Development and testing of a new method, BORA-Release, for qualitative and quantitative risk analysis of hydrocarbon releases Safety barriers are defined as physical and/or non-physical means planned to prevent, control, or mitigate undesired events or accidents. The means may range from a single technical unit or human actions, to a complex socio-technical system. It is useful to distinguish between barrier functions and barrier systems. Barrier functions describe the purpose of safety barriers or what the safety barriers shall do in order to prevent, control, or mitigate undesired events or accidents. Barrier systems describe how a barrier function is realized or executed. If the barrier system is functioning, the barrier function is performed. If a barrier function is performed successfully, it should have a direct and significant effect on the occurrence and/or consequences of an undesired event or accident. It is recommended to address the following attributes to characterize the performance of safety barriers; a) functionality/effectiveness, b) reliability/ availability, c) response time, d) robustness, and e) triggering event or condition. For some types of barriers, not all the attributes are relevant or necessary in order to describe the barrier performance. The presented hydrocarbon release scenarios include initiating events, barrier functions introduced to prevent hydrocarbon releases, and barrier systems realizing the barrier functions. Both technical and human

Mollusk communities of the central Congo River shaped by combined effects of barriers, environmental gradients, and species dispersal

Directory of Open Access Journals (Sweden)

Oscar Wembo Ndeo

2017-05-01

Full Text Available Rapids, falls, and cascades might act as barriers for freshwater species, determining the species community up- and downstream of barriers. However, they affect community composition not only by acting as barriers but also by their influence on environmental gradients. Moreover, the directional dispersal of species along the watercourse might determine community composition. A suitable system to study these differential effects is the Congo River, the world’s second largest river by discharge. The small ‘Upper Congo Rapids’ ecoregion features several rapids known as barrier for fishes. The Wagenia Cataracts at the town of Kisangani constitute the strongest drop of the Congo River and several studies have emphasized its role as barrier for fish distribution. Alternative explanations for this pattern, however, are rarely evaluated. Though mollusks represent a vital component of the macrozoobenthos, with distribution patterns and underlying drivers often distinct from that of fishes, virtually no field surveys of the Congo River have been reported for decades. We collected and determined mollusks of 51 stations, recorded environmental conditions, and generated proxies for directional species dispersal and an indirect barrier effect. Those variables were subjected to distance-based redundancy analyses and variation partitioning in order to test whether the mollusk community compositions are better explained by an individual or combined influence of the direct and indirect effect of the cataract barrier, environmental conditions, and downstream-directed dispersal. Our survey showed an exclusive upstream/downstream distribution for just four out of the 19 species, suggesting a limited barrier effect. We revealed no direct influence of the barrier itself on community composition but of substrate type. However, we found an indirect effect of the barrier through replacing spatially structured communities upstream of the cataract with more uniform

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

International Nuclear Information System (INIS)

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

1998-01-01

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

Barriers and solutions for expansion of electricity grids—the German experience

International Nuclear Information System (INIS)

Steinbach, Armin

2013-01-01

There is a lack of synchronization in the expansion of renewable energies and the modernization of the electricity grid infrastructure. Main barriers to grid development are the insufficient regulatory framework, an inefficient allocation of planning and authorization competences and a lack of public acceptance of new grids. As response to these barriers, Germany has implemented a fundamental reform of the planning and authorization of high voltage power lines. We analyze the new regime as to what extent it is able to eliminate existing barriers to grid expansion and thus can serve as model for other countries. We find that the establishment of a single authority competent for planning, authorization and regulation may abolish existing lack of coordination. Also, the implementation of early participation on basis of various consultations phases has been proved to be very successful in the establishment of the first grid development plan. Stricter administrative time-limits and sanctions are likely to have an accelerating effect. And an increased openness to new technologies on basis of pilot project gives grid operators more flexibility in grid development. Recently, the European Commission adopted the German approach in its policy guidelines for other EU members. - Highlights: • Assessment of barriers to electricity grid infrastructure. • Needs for better, simplified and uniform regulatory framework. • German reform of planning and authorization procedure

Latest Advances in the Generation of Single Photons in Silicon Carbide

Directory of Open Access Journals (Sweden)

Albert Boretti

2016-06-01

Full Text Available The major barrier for optical quantum information technologies is the absence of reliable single photons sources providing non-classical light states on demand which can be easily and reliably integrated with standard processing protocols for quantum device fabrication. New methods of generation at room temperature of single photons are therefore needed. Heralded single photon sources are presently being sought based on different methods built on different materials. Silicon Carbide (SiC has the potentials to serve as the preferred material for quantum applications. Here, we review the latest advances in single photon generation at room temperatures based on SiC.

Through-barrier electromagnetic imaging with an atomic magnetometer.

Science.gov (United States)

Deans, Cameron; Marmugi, Luca; Renzoni, Ferruccio

2017-07-24

We demonstrate the penetration of thick metallic and ferromagnetic barriers for imaging of conductive targets underneath. Our system is based on an 85 Rb radio-frequency atomic magnetometer operating in electromagnetic induction imaging modality in an unshielded environment. Detrimental effects, including unpredictable magnetic signatures from ferromagnetic screens and variations in the magnetic background, are automatically compensated by active compensation coils controlled by servo loops. We exploit the tunability and low-frequency sensitivity of the atomic magnetometer to directly image multiple conductive targets concealed by a 2.5 mm ferromagnetic steel shield and/or a 2.0 mm aluminium shield, in a single scan. The performance of the atomic magnetometer allows imaging without any prior knowledge of the barriers or the targets, and without the need of background subtraction. A dedicated edge detection algorithm allows automatic estimation of the targets' size within 3.3 mm and of their position within 2.4 mm. Our results prove the feasibility of a compact, sensitive and automated sensing platform for imaging of concealed objects in a range of applications, from security screening to search and rescue.

Spin-related tunneling through a nanostructured electric-magnetic barrier on the surface of a topological insulator.

Science.gov (United States)

Wu, Zhenhua; Li, Jun

2012-01-27

We investigate quantum tunneling through a single electric and/or magnetic barrier on the surface of a three-dimensional topological insulator. We found that (1) the propagating behavior of electrons in such system exhibits a strong dependence on the direction of the incident electron wavevector and incident energy, giving the possibility to construct a wave vector and/or energy filter; (2) the spin orientation can be tuned by changing the magnetic barrier structure as well as the incident angles and energies.PACS numbers: 72.25.Dc; 73.20.-r; 73.23.-b; 75.70.-i.

Surface single-molecule dynamics controlled by entropy at low temperatures

Science.gov (United States)

Gehrig, J. C.; Penedo, M.; Parschau, M.; Schwenk, J.; Marioni, M. A.; Hudson, E. W.; Hug, H. J.

2017-02-01

Configuration transitions of individual molecules and atoms on surfaces are traditionally described using an Arrhenius equation with energy barrier and pre-exponential factor (attempt rate) parameters. Characteristic parameters can vary even for identical systems, and pre-exponential factors sometimes differ by orders of magnitude. Using low-temperature scanning tunnelling microscopy (STM) to measure an individual dibutyl sulfide molecule on Au(111), we show that the differences arise when the relative position of tip apex and molecule changes by a fraction of the molecule size. Altering the tip position on that scale modifies the transition's barrier and attempt rate in a highly correlated fashion, which results in a single-molecular enthalpy-entropy compensation. Conversely, appropriately positioning the STM tip allows selecting the operating point on the compensation line and modifying the transition rates. The results highlight the need to consider entropy in transition rates of single molecules, even at low temperatures.

Osmotic blood-brain barrier modification: clinical documentation by enhanced CT scanning and/or radionuclide brain scanning

International Nuclear Information System (INIS)

Neuwelt, E.A.; Specht, H.D.; Howieson, J.; Haines, J.E.; Bennett, M.J.; Hill, S.A.; Frenkel, E.P.

1983-01-01

Results of initial clinical trials of brain tumor chemotherapy after osmotic blood-brain barrier disruption are promising. In general, the procedure is well tolerated. The major complication has been seizures. In this report, data are presented which indicate that the etiology of these seizures is related to the use of contrast agent (meglumine iothalamate) to monitor barrier modification. A series of 19 patients underwent a total of 85 barrier modification procedures. Documentation of barrier disruption was monitored by contrast-enhanced computed tomographic (CT) scanning, radionuclide brain scanning, or a combination of both techniques. In 56 procedures (19 patients) monitored by enhanced CT, seizures occurred a total of 10 times in eight patients. Twenty-three barrier modification procedures (in nine of these 19 patients) documented by nuclear brain scans alone, however, resulted in only one focal motor seizure in each of two patients. In eight of the 19 patients who had seizures after barrier disruption and enhanced CT scan, four subsequently had repeat procedures monitored by radionuclide scan alone. In only one of these patients was further seizure activity noted; a single focal motor seizure was observed. Clearly, the radionuclide brain scan does not have the sensitivity and spatial resolution of enhanced CT, but at present it appears safer to monitor barrier modification by this method and to follow tumor growth between barrier modifications by enhanced CT. Four illustrative cases showing methods, problems, and promising results are presented

A dominant mutation in mediator of paramutation2, one of three second-largest subunits of a plant-specific RNA polymerase, disrupts multiple siRNA silencing processes.

Science.gov (United States)

Sidorenko, Lyudmila; Dorweiler, Jane E; Cigan, A Mark; Arteaga-Vazquez, Mario; Vyas, Meenal; Kermicle, Jerry; Jurcin, Diane; Brzeski, Jan; Cai, Yu; Chandler, Vicki L

2009-11-01

Paramutation involves homologous sequence communication that leads to meiotically heritable transcriptional silencing. We demonstrate that mop2 (mediator of paramutation2), which alters paramutation at multiple loci, encodes a gene similar to Arabidopsis NRPD2/E2, the second-largest subunit of plant-specific RNA polymerases IV and V. In Arabidopsis, Pol-IV and Pol-V play major roles in RNA-mediated silencing and a single second-largest subunit is shared between Pol-IV and Pol-V. Maize encodes three second-largest subunit genes: all three genes potentially encode full length proteins with highly conserved polymerase domains, and each are expressed in multiple overlapping tissues. The isolation of a recessive paramutation mutation in mop2 from a forward genetic screen suggests limited or no functional redundancy of these three genes. Potential alternative Pol-IV/Pol-V-like complexes could provide maize with a greater diversification of RNA-mediated transcriptional silencing machinery relative to Arabidopsis. Mop2-1 disrupts paramutation at multiple loci when heterozygous, whereas previously silenced alleles are only up-regulated when Mop2-1 is homozygous. The dramatic reduction in b1 tandem repeat siRNAs, but no disruption of silencing in Mop2-1 heterozygotes, suggests the major role for tandem repeat siRNAs is not to maintain silencing. Instead, we hypothesize the tandem repeat siRNAs mediate the establishment of the heritable silent state-a process fully disrupted in Mop2-1 heterozygotes. The dominant Mop2-1 mutation, which has a single nucleotide change in a domain highly conserved among all polymerases (E. coli to eukaryotes), disrupts both siRNA biogenesis (Pol-IV-like) and potentially processes downstream (Pol-V-like). These results suggest either the wild-type protein is a subunit in both complexes or the dominant mutant protein disrupts both complexes. Dominant mutations in the same domain in E. coli RNA polymerase suggest a model for Mop2-1 dominance

Transport barriers in plasmas

International Nuclear Information System (INIS)

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

2012-01-01

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

Switzerland's largest wood-pellet factory in Balsthal

International Nuclear Information System (INIS)

Stohler, F.

2004-01-01

This article describes how a small Swiss electricity utility has broken out of its traditional role in power generation and the distribution of electricity and gone into the production of wood pellets. The pellets, which are made from waste wood (sawdust) available from wood processing companies, are produced on a large scale in one of Europe's largest pellets production facilities. The boom in the use of wood pellets for heating purposes is discussed. The article discusses this unusual approach for a Swiss power utility, which also operates a wood-fired power station and is even involved in an incineration plant for household wastes. The markets being aimed for in Switzerland and in Europe are described, including modern low-energy-consumption housing projects. A further project is described that is to use waste wood available from a large wood processing facility planned in the utility's own region

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

Science.gov (United States)

Mitragotri, Samir

2013-01-01

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

A general approach to break the concentration barrier in single-molecule imaging

KAUST Repository

Loveland, Anna B.; Habuchi, Satoshi; Walter, Johannes C.; van Oijen, Antoine M.

2012-01-01

Single-molecule fluorescence imaging is often incompatible with physiological protein concentrations, as fluorescence background overwhelms an individual molecule's signal. We solve this problem with a new imaging approach called PhADE (Photo

Apparent Barrier Height in Scanning Tunneling Microscopy Revisited

DEFF Research Database (Denmark)

Olesen, L.; Brandbyge, Mads; Sørensen, Mads Reinholdt

1996-01-01

The apparent barrier height phi(ap), that is, the rate of change of the logarithm of the conductance with tip-sample separation in a scanning tunneling microscope (STM), has been measured for Ni, Pt, and Au single crystal surfaces. The results show that phi(ap) is constant until point contact...... is reached rather than decreasing at small tunneling gap distances, as previously reported. The findings for phi(ap) can be accounted for theoretically by including the relaxations of the tip-surface junction in an STM due to the strong adhesive forces at close proximity. These relaxation effects are shown...

AN INVESTIGATION INTO THE BARRIERS FACING BLACK AND MINORITY ETHNICS WITHIN THE UK CONSTRUCTION INDUSTRY

Directory of Open Access Journals (Sweden)

Vian Ahmed

2008-12-01

Full Text Available The UK construction industry is one of the largest employers, positioned as the country’s top employer with over two million employees and projected to continue growth as far as 2011. However, it is facing ongoing skills shortages in a number of professional areas and tends to lack an ethnic diversity of workers compared to the White community of workers across the whole economy. The government’s Ethnic Minority Employment Task Force shows that for any given level of qualification, a Black or ethnic minority person is less likely to be employed, than a similarly qualified White person. Current research into issues surrounding ethnicity, from academia to employment is scarce, particularly in entry and process development within the construction industry. The aim of this paper is to outline the findings from perceptional and experiential barriers of Black and Minority Ethnics (BMEs students and employees, in order to identify perceptional and actual barriers that lead to the under-representation of BMEs within the construction industry; and also to suggest how better knowledge flow mechanisms could lead to a more balanced development, particularly in terms of ethnic diversification in the UK construction industry. The aim was achieved by adopting qualitative and quantitative methods including questionnaire surveys of undergraduate students in a construction related program, employees working within the construction industry and interviews with company directors and human resource managers. The image of the construction industry is found to be one of the major barriers for entry into the industry. Language and cultures form additional barriers for a range of ethnic groupings. Support, in the form of recruitment events, training, mentoring, professional networking, as well as work placement and experience schemes, can smooth entry, retention and progression within the construction industry.

Enantiopure heterobimetallic single-chain magnets from the chiral Ru(III) building block.

Science.gov (United States)

Ru, Jing; Gao, Feng; Wu, Tao; Yao, Min-Xia; Li, Yi-Zhi; Zuo, Jing-Lin

2014-01-21

A pair of one-dimensional enantiomers based on the versatile chiral dicyanoruthenate(III) building block have been synthesized and they are chiral single-chain magnets with the effective spin-reversal barrier of 28.2 K.

The global diversion of pharmaceutical drugs. India: the third largest illicit opium producer?

Science.gov (United States)

Paoli, Letizia; Greenfield, Victoria A; Charles, Molly; Reuter, Peter

2009-03-01

This paper explores India's role in the world illicit opiate market, particularly its role as a producer. India, a major illicit opiate consumer, is also the sole licensed exporter of raw opium: this unique status may be enabling substantial diversion to the illicit market. Participant observation and interviews were carried out at eight different sites. Information was also drawn from all standard secondary sources and the analysis of about 180 drug-related criminal proceedings reviewed by Indian High Courts and the Supreme Court from 1985 to 2001. Diversion from licit opium production takes place on such a large scale that India may be the third largest illicit opium producer after Afghanistan and Burma. With the possible exceptions of 2005 and 2006, 200-300 tons of India's opium may be diverted yearly. After estimating India's opiate consumption on the basis of UN-reported prevalence estimates, we find that diversion from licit production might have satisfied a quarter to more than a third of India's illicit opiate demand to 2004. India is not only among the world's largest consumer of illicit opiates but also one of the largest illicit opium producers. In contrast to all other illicit producers, India owes the latter distinction not to blatantly illicit cultivation but to diversion from licit cultivation. India's experience suggests the difficulty of preventing substantial leakage, even in a relatively well-governed nation.

Trajectory-based understanding of the quantum-classical transition for barrier scattering

Science.gov (United States)

Chou, Chia-Chun

2018-06-01

The quantum-classical transition of wave packet barrier scattering is investigated using a hydrodynamic description in the framework of a nonlinear Schrödinger equation. The nonlinear equation provides a continuous description for the quantum-classical transition of physical systems by introducing a degree of quantumness. Based on the transition equation, the transition trajectory formalism is developed to establish the connection between classical and quantum trajectories. The quantum-classical transition is then analyzed for the scattering of a Gaussian wave packet from an Eckart barrier and the decay of a metastable state. Computational results for the evolution of the wave packet and the transmission probabilities indicate that classical results are recovered when the degree of quantumness tends to zero. Classical trajectories are in excellent agreement with the transition trajectories in the classical limit, except in some regions where transition trajectories cannot cross because of the single-valuedness of the transition wave function. As the computational results demonstrate, the process that the Planck constant tends to zero is equivalent to the gradual removal of quantum effects originating from the quantum potential. This study provides an insightful trajectory interpretation for the quantum-classical transition of wave packet barrier scattering.

BALU: Largest autoclave research facility in the world

Directory of Open Access Journals (Sweden)

Hakan Ucan

2016-03-01

Full Text Available Among the large-scale facilities operated at the Center for Lightweight-Production-Technology of the German Aerospace Center in Stade BALU is the world's largest research autoclave. With a loading length of 20m and a loading diameter of 5.8 m the main objective of the facility is the optimization of the curing process operated by components made of carbon fiber on an industrial scale. For this reason, a novel dynamic autoclaving control has been developed that is characterized by peripheral devices to expend the performance of the facility for differential applications, by sensing systems to detect the component state throughout the curing process and by a feedback system, which is capable to intervene into the running autoclave process.

DISCOVERY OF THE LARGEST KNOWN LENSED IMAGES FORMED BY A CRITICALLY CONVERGENT LENSING CLUSTER

International Nuclear Information System (INIS)

Zitrin, Adi; Broadhurst, Tom

2009-01-01

We identify the largest known lensed images of a single spiral galaxy, lying close to the center of the distant cluster MACS J1149.5+2223 (z = 0.544). These images cover a total area of ≅150 mbox '' and are magnified ≅200 times. Unusually, there is very little image distortion, implying that the central mass distribution is almost uniform over a wide area (r ≅ 200 kpc) with a surface density equal to the critical density for lensing, corresponding to maximal lens magnification. Many fainter multiply lensed galaxies are also uncovered by our model, outlining a very large tangential critical curve, of radius r ≅ 170 kpc, posing a potential challenge for the standard LCDM cosmology. Because of the uniform central mass distribution, a particularly clean measurement of the mass of the brightest cluster galaxy is possible here, for which we infer stars contribute most of the mass within a limiting radius of ≅30 kpc, with a mass-to-light ratio of M/L B ≅ 4.5(M/L) sun . This cluster with its uniform and central mass distribution acts analogously to a regular magnifying glass, converging light without distorting the images, resulting in the most powerful lens yet discovered for accessing the faint high-z universe.

Performing a local barrier operation

Science.gov (United States)

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

2014-03-04

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

The role of multiple barriers in assuring waste package reliability

International Nuclear Information System (INIS)

Bradford, R.M.

1993-08-01

Yucca Mountain in southwestern Nevada is being studied as a potential repository site for the permanent storage of high-level nuclear waste. Regulators have set performance standards that the potential repository must meet in order to obtain regulatory approval. Nuclear Regulatory Commission (NRC) regulations state that containment of radioactivity must be ''substantially complete'' for the first 1000 years after closure of the facility. Thereafter, the acceptable annual limit on releases is 1/100,000 of each radionuclide remaining in the inventory after 1000 years. To demonstrate that the potential facility is in compliance with the regulations, it is necessary to obtain some understanding of the probability distribution of the cumulative quantity of releases by certain time points. This paper will discuss the probability distribution of waste container lifetimes and how the understanding of this distribution will play a role in finding the distribution of the release quantities over time. It will be shown that, for reasonable assumptions about the process of barrier failure, the reliability of a multiple-barrier container can be achieved and demonstrated much more readily than a container consisting of a single barrier. The discussion will focus primarily on the requirement of substantially complete containment for the first 1000 years

Oxygen Barrier Coating Deposited by Novel Plasma-enhanced Chemical Vapor Deposition

DEFF Research Database (Denmark)

Jiang, Juan; Benter, M.; Taboryski, Rafael Jozef

2010-01-01

We report the use of a novel plasma-enhanced chemical vapor deposition chamber with coaxial electrode geometry for the SiOx deposition. This novel plasma setup exploits the diffusion of electrons through the inner most electrode to the interior samples space as the major energy source. This confi......We report the use of a novel plasma-enhanced chemical vapor deposition chamber with coaxial electrode geometry for the SiOx deposition. This novel plasma setup exploits the diffusion of electrons through the inner most electrode to the interior samples space as the major energy source...... effect of single-layer coatings deposited under different reaction conditions was studied. The coating thickness and the carbon content in the coatings were found to be the critical parameters for the barrier property. The novel barrier coating was applied on different polymeric materials...

Dynamical barrier for the formation of solitary waves in discrete lattices

International Nuclear Information System (INIS)

Kevrekidis, P.G.; Espinola-Rocha, J.A.; Drossinos, Y.; Stefanov, A.

2008-01-01

We consider the problem of the existence of a dynamical barrier of 'mass' that needs to be excited on a lattice site to lead to the formation and subsequent persistence of localized modes for a nonlinear Schroedinger lattice. We contrast the existence of a dynamical barrier with its absence in the static theory of localized modes in one spatial dimension. We suggest an energetic criterion that provides a sufficient, but not necessary, condition on the amplitude of a single-site initial condition required to form a solitary wave. We show that this effect is not one-dimensional by considering its two-dimensional analog. The existence of a sufficient condition for the excitation of localized modes in the non-integrable, discrete, nonlinear Schroedinger equation is compared to the dynamics of excitations in the integrable, both discrete and continuum, version of the nonlinear Schroedinger equation

Phase characterization of Re-based diffusion barrier layer on Nb substrate

International Nuclear Information System (INIS)

Sugiarti, Eni; Wang, Youngmin; Hashimoto, Naoyuki; Ohnuki, Somei; Narita, Toshio

2011-01-01

An electron microscopy phase characterization was carried out for a Re-based diffusion barrier layer, which was deposited on the Nb substrate used as an ultra high temperature material. The coating process produced three layers; an outer Cr(Re) layer, an intermediate Cr-Nb-Re layer, and an inner Nb(Re) layer. The Cr-Nb-Re layer is considered to act as a diffusion barrier layer between the substrate and the outer Cr(Re) reservoir layer. The Cr(Re) and Nb(Re) layers are in single phase with a similar bcc structures, but they are different in structure from the intermediate layer, which is composed of a dual phase of Re 63 Cr 20 Nb 17 with a cubic structure and Nb 42 Re 33 Cr 25 with a hexagonal structure determined by transmission electron microscopy (TEM) in this study. (author)

Summary report on close-coupled subsurface barrier technology: Initial field trials to full-scale demonstration

International Nuclear Information System (INIS)

Heiser, J.H.

1997-09-01

The primary objective of this project was to develop and demonstrate the installation and measure the performance of a close-coupled barrier for the containment of subsurface waste or contaminant migration. A close-coupled barrier is produced by first installing a conventional, low-cost, cement-grout containment barrier followed by a thin lining of a polymer grout. The resultant barrier is a cement-polymer composite that has economic benefits derived from the cement and performance benefits from the durable and resistant polymer layer. The technology has matured from a regulatory investigation of the issues concerning the use of polymers to laboratory compatibility and performance measurements of various polymer systems to a pilot-scale, single column injection at Sandia to full-scale demonstration. The feasibility of the close-coupled barrier concept was proven in a full-scale cold demonstration at Hanford, Washington and then moved to the final stage with a full-scale demonstration at an actual remediation site at Brookhaven National Laboratory (BNL). At the Hanford demonstration the composite barrier was emplaced around and beneath a 20,000 liter tank. The secondary cement layer was constructed using conventional jet grouting techniques. Drilling was completed at a 45 degree angle to the ground, forming a cone-shaped barrier. The primary barrier was placed by panel jet-grouting with a dual-wall drill stem using a two part polymer grout. The polymer chosen was a high molecular weight acrylic. At the BNL demonstration a V-trough barrier was installed using a conventional cement grout for the secondary layer and an acrylic-gel polymer for the primary layer. Construction techniques were identical to the Hanford installation. This report summarizes the technology development from pilot- to full-scale demonstrations and presents some of the performance and quality achievements attained

Barriers and drivers for energy efficiency: Different perspectives from an exploratory study in the Netherlands

International Nuclear Information System (INIS)

Cagno, Enrico; Trianni, Andrea; Abeelen, Christiaan; Worrell, Ernst; Miggiano, Federica

2015-01-01

Highlights: • We investigated the perception of barriers and drivers and mechanisms regulating them. • Firms agree on the most important barriers and drivers. • Firms agree on the most critical decision-making steps and actors promoting drivers. • Major external actors perceive barriers, drivers and mechanisms differently. • Success of voluntary agreements depends on the link to other policy instruments. - Abstract: Increased energy efficiency represents a crucial opportunity for European industrial sustainability, but several barriers still need to be tackled. Thus, it is crucial to understand the existing mismatches between the perception of enterprises and what the major actors promoting energy efficiency believe enterprises suffer from and need within the decision-making process. To do so, we have performed an exploratory investigation analysing a set of manufacturing enterprises participating in the Dutch voluntary agreements. The study involved the major external actors, i.e. the national energy agency, governmental and industrial organisations, to map their views on the decision-making process. Results show that enterprises agree not only on the most important barriers and drivers, but also on the mechanisms underlying them. However, even a general common understanding of the barriers is disputed when major external actors are considered, as they only agree on the primary role of economic barriers. Mismatches appear when considering how single barriers affect the decision-making process and which drivers – and actors promoting them – need to be addressed. Although voluntary agreements represent the most popular instrument on energy efficiency in the Netherlands, they do not seem to be considered by small and medium-sized enterprises as a stimulus for improving energy efficiency. Crucial for future success are the link with other policy instruments, and the degree to which the instruments trigger the right drivers and barriers at the right

Barrier island facies models and recognition criteria

Science.gov (United States)

Mulhern, J.; Johnson, C. L.

2017-12-01

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

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.

Engineered barriers: current status

International Nuclear Information System (INIS)

Atkinson, A.; Marsh, G.P.

1988-01-01

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

Anisotropic Lithium Insertion Behavior in Silicon Nanowires: Binding Energy, Diffusion Barrier, and Strain Effect

KAUST Repository

Zhang, Qianfan; Cui, Yi; Wang, Enge

2011-01-01

Silicon nanowires (SiNWs) have recently been shown to be promising as high capacity lithium battery anodes. SiNWs can be grown with their long axis along several different crystallographic directions. Due to distinct atomic configuration and electronic structure of SiNWs with different axial orientations, their lithium insertion behavior could be different. This paper focuses on the characteristics of single Li defects, including binding energy, diffusion barriers, and dependence on uniaxial strain in [110], [100], [111], and [112] SiNWs. Our systematic ab initio study suggests that the Si-Li interaction is weaker when the Si-Li bond direction is aligned close to the SiNW long axis. This results in the [110] and [111] SiNWs having the highest and lowest Li binding energy, respectively, and it makes the diffusion barrier along the SiNW axis lower than other pathways. Under external strain, it was found that [110] and [001] SiNWs are the most and least sensitive, respectively. For diffusion along the axial direction, the barrier increases (decreases) under tension (compression). This feature results in a considerable difference in the magnitude of the energy barrier along different diffusion pathways. © 2011 American Chemical Society.

Anisotropic Lithium Insertion Behavior in Silicon Nanowires: Binding Energy, Diffusion Barrier, and Strain Effect

KAUST Repository

Zhang, Qianfan

2011-05-19

Silicon nanowires (SiNWs) have recently been shown to be promising as high capacity lithium battery anodes. SiNWs can be grown with their long axis along several different crystallographic directions. Due to distinct atomic configuration and electronic structure of SiNWs with different axial orientations, their lithium insertion behavior could be different. This paper focuses on the characteristics of single Li defects, including binding energy, diffusion barriers, and dependence on uniaxial strain in [110], [100], [111], and [112] SiNWs. Our systematic ab initio study suggests that the Si-Li interaction is weaker when the Si-Li bond direction is aligned close to the SiNW long axis. This results in the [110] and [111] SiNWs having the highest and lowest Li binding energy, respectively, and it makes the diffusion barrier along the SiNW axis lower than other pathways. Under external strain, it was found that [110] and [001] SiNWs are the most and least sensitive, respectively. For diffusion along the axial direction, the barrier increases (decreases) under tension (compression). This feature results in a considerable difference in the magnitude of the energy barrier along different diffusion pathways. © 2011 American Chemical Society.

Material Barriers to Diffusive Mixing

Science.gov (United States)

Haller, George; Karrasch, Daniel

2017-11-01

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

Estimates of ambient groundwater velocity in the alluvium south of Yucca Mountain from single-well tracer tests

International Nuclear Information System (INIS)

Reimus, P.W.; Umari, M.J.; Roback, R.; Earle, John; Darnell, Jon; Farnham, Irene

2002-01-01

The saturated alluvium located south of Yucca Mountain, Nevada is expected to serve as the final barrier to radionuclide transport from the proposed high-level nuclear waste repository at Yucca Mountain. The alluvium will act as a barrier if radionuclides breach the engineered barriers in the repository, move through the unsaturated zone beneath the repository to the water table, and then migrate through saturated volcanic tuffs to the alluvium. Three single-well injection-withdrawal tracer tests were conducted between December 2000 and April 2001 in the saturated alluviuni at NC-EWDP-19D1, a Nye County-Early Warning Drilling Program well located about 18 km south of Yucca Mountain. The tests had the objectives of (1) distinguishing between a single- and a dual-porosity conceptual radionuclide transport model for the alluvium, and (2) obtaining estimates of ambient groundwater velocity in the alluvium.

Pressure tuning of anisotropy barrier in Fe8 SMMs probed using high frequency EPR

Science.gov (United States)

Thirunavukkuarasu, Komalavalli; Beedle, Christopher; Tozer, Stanley; Hill, Stephen

2014-03-01

Single-molecule magnets (SMMs) are spin systems with large spin ground state where quantum phenomena such as tunneling of magnetization via a considerable anisotropy barrier manifest. One such SMM that has been extensively studied is [Fe8O2(OH)12(tacn)6]Br8.9H2O, also known as Fe8, with a giant spin ground state of S=10. The eight Fe atoms bridged by the ligands form a butterfly structure where six Fe atoms have spins up and two spins down in the simplest model. This structure in fact gives rise to geometrical spin frustration effects within the cluster. By varying the interaction between the spins, manipulation of quantum tunneling in SMMs may be achieved. Typically, the manipulation of spin interactions is realized using chemical methods. As an alternative approach, we employ high pressure to induce changes in the ligand-field environment of the Fe atoms. In this presentation, the pressure-dependent changes in the anisotropy barrier in single crystal Fe8 SMMs investigated by high frequency electron paramagnetic resonance measurements will be discussed.

Growth of Single- and Bilayer ZnO on Au(111) and Interaction with Copper

Energy Technology Data Exchange (ETDEWEB)

Deng, Xingyi; Yao, Kun; Sun, Keju; Li, Wei-Xue; Lee, Junseok; Matranga, Christopher

2013-05-02

The stoichiometric single- and bi-layer ZnO(0001) have been prepared by reactive deposition of Zn on Au(111) and studied in detail with X-ray photoelectron spectroscopy, scanning tunneling microscopy, and density functional theory calculations. Both single- and bi-layer ZnO(0001) adopt a planar, graphite-like structure similar to freestanding ZnO(0001) due to the weak van der Waals interactions dominating their adhesion with the Au(111) substrate. At higher temperature, the single-layer ZnO(0001) converts gradually to bi-layer ZnO(0001) due to the twice stronger interaction between two ZnO layers than the interfacial adhesion of ZnO with Au substrate. It is found that Cu atoms on the surface of bi-layer ZnO(0001) are mobile with a diffusion barrier of 0.31 eV, and likely to agglomerate and form nanosized particles at low coverages; while Cu atoms tend to penetrate a single layer of ZnO(0001) with a barrier of 0.10 eV, resulting in a Cu free surface.

Diabetes and diet : managing dietary barriers

NARCIS (Netherlands)

Friele, R.D.

1989-01-01

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

Cancer symptom awareness and barriers to symptomatic presentation in England—are we clear on cancer?

Science.gov (United States)

Niksic, M; Rachet, B; Warburton, F G; Wardle, J; Ramirez, A J; Forbes, L J L

2015-01-01

Background: Low cancer awareness may contribute to delayed diagnosis and poor cancer survival. We aimed to quantify socio-demographic differences in cancer symptom awareness and barriers to symptomatic presentation in the English population. Methods: Using a uniquely large data set (n=49 270), we examined the association of cancer symptom awareness and barriers to presentation with age, gender, marital status and socio-economic position (SEP), using logistic regression models to control for confounders. Results: The youngest and oldest, the single and participants with the lowest SEP recognised the fewest cancer symptoms, and reported most barriers to presentation. Recognition of nine common cancer symptoms was significantly lower, and embarrassment, fear and difficulties in arranging transport to the doctor's surgery were significantly more common in participants living in the most deprived areas than in the most affluent areas. Women were significantly more likely than men to both recognise common cancer symptoms and to report barriers. Women were much more likely compared with men to report that fear would put them off from going to the doctor. Conclusions: Large and robust socio-demographic differences in recognition of some cancer symptoms, and perception of some barriers to presentation, highlight the need for targeted campaigns to encourage early presentation and improve cancer outcomes. PMID:26125450

Cancer symptom awareness and barriers to symptomatic presentation in England--are we clear on cancer?

Science.gov (United States)

Niksic, M; Rachet, B; Warburton, F G; Wardle, J; Ramirez, A J; Forbes, L J L

2015-07-28

Low cancer awareness may contribute to delayed diagnosis and poor cancer survival. We aimed to quantify socio-demographic differences in cancer symptom awareness and barriers to symptomatic presentation in the English population. Using a uniquely large data set (n=49 270), we examined the association of cancer symptom awareness and barriers to presentation with age, gender, marital status and socio-economic position (SEP), using logistic regression models to control for confounders. The youngest and oldest, the single and participants with the lowest SEP recognised the fewest cancer symptoms, and reported most barriers to presentation. Recognition of nine common cancer symptoms was significantly lower, and embarrassment, fear and difficulties in arranging transport to the doctor's surgery were significantly more common in participants living in the most deprived areas than in the most affluent areas. Women were significantly more likely than men to both recognise common cancer symptoms and to report barriers. Women were much more likely compared with men to report that fear would put them off from going to the doctor. Large and robust socio-demographic differences in recognition of some cancer symptoms, and perception of some barriers to presentation, highlight the need for targeted campaigns to encourage early presentation and improve cancer outcomes.

Single Top quark production cross section using ATLAS detector at the LHC

CERN Document Server

Estrada Pastor, Oscar; The ATLAS collaboration

2018-01-01

Measurements of single top-quark production in proton-proton collisions are presented based on the 8 TeV and 13 TeV ATLAS datasets. In the leading order process, a W boson is exchanged in the t-channel. The cross-section for the production of single top-quarks and single anti-top-quarks, their ratio, as well as differential cross-section measurements are also reported. These analyses include limits on anomalous contributions to the Wtb vertex and measurement of the top quark polarization. Measurements of the inclusive and differential cross-sections for the production of a single top quark in association with a W boson, the second largest single-top production mode, are also presented. Finally, evidence for s-channel single-top production in the 8 TeV ATLAS dataset is presented. All measurements are compared to state-of-the-art theoretical calculations.

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.

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. ...

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

Barriers Against Implementing Blunt Abdominal Trauma Guidelines in a Hospital: A Qualitative Study.

Science.gov (United States)

Zaboli, Rouhollah; Tofighi, Shahram; Aghighi, Ali; Shokouh, Seyyed Javad Hosaini; Naraghi, Nader; Goodarzi, Hassan

2016-08-01

Clinical practice guidelines are structured recommendations that help physicians and patients to make proper decisions when dealing with a specific clinical condition. Because blunt abdominal trauma causes a various range of mild, single-system, and multisystem injuries, early detection will help to reduce mortality and resulting disability. Emergency treatment should be initiated based on CPGs. This study aimed to determine the variables affecting implementing blunt abdominal trauma CPGs in an Iranian hospital. This study was conducted as a qualitative and phenomenology study in the Family Hospital in Tehran (Iran) in 2015. The research population included eight experts and key people in the area of blunt abdominal trauma clinical practice guidelines. Sampling was based on purposive and nonrandom methods. A semistructured interview was done for the data collection. A framework method was applied for the data analysis by using Atlas.ti software. After framework analyzing and various reviewing and deleting and combining the codes from 251 codes obtained, 15 families and five super families were extracted, including technical knowledge barriers, economical barriers, barriers related to deployment and monitoring, political will barriers, and managing barriers. Structural reform is needed for eliminating the defects available in the healthcare system. As with most of the codes, subconcepts and concepts are classified into the field of human resources; it seems that the education and knowledge will be more important than other resources such as capital and equipment.

Canada's largest co-gen project

International Nuclear Information System (INIS)

Salaff, S.

2000-01-01

In November 2000, the TransAlta Energy Corp. began construction on its $400 million natural gas fuelled cogeneration project in Sarnia Ontario. The Sarnia Regional Cogeneration Project (SRCP) is designed to integrate a new 440 MW cogeneration facility to be built at the Sarnia Division of Dow Chemicals Canada Inc. with nearby existing generators totaling 210 MW at Dow and Bayer Inc. At 650 MW, the new facility will rank as Canada's largest cogeneration installation. Commercial operation is scheduled for October 2002. TransAlta owns three natural gas fuelled cogeneration facilities in Ontario (in Ottawa, Mississauga and Windsor) totaling 250 MW. The cost of electric power in Ontario is currently controlled by rising natural gas prices and the supply demand imbalance. This balance will be significantly affected by the possible return to service of 2000 MW of nuclear generating capacity. The SRCP project was announced just prior to the Ontario Energy Competition Act of October 1998 which committed the province to introduce competition to the electricity sector and which created major uncertainties in the electricity market. Some of the small, 25 MW projects which survived the market uncertainty included the Toronto-based Toromont Energy Ltd. project involving gas fuelled cogeneration and methane gas generation from landfill projects in Sudbury and Waterloo. It was emphasized that cogeneration and combined heat and power projects have significant environmental advantages over large combined cycle facilities. The Ontario Energy Board is currently considering an application from TransAlta to link the SRCP facility to Ontario's Hydro One Network Inc.'s transmission grid. 1 fig

Direct Visualization of Barrier Crossing Dynamics in a Driven Optical Matter System.

Science.gov (United States)

Figliozzi, Patrick; Peterson, Curtis W; Rice, Stuart A; Scherer, Norbert F

2018-04-25

A major impediment to a more complete understanding of barrier crossing and other single-molecule processes is the inability to directly visualize the trajectories and dynamics of atoms and molecules in reactions. Rather, the kinetics are inferred from ensemble measurements or the position of a transducer ( e. g., an AFM cantilever) as a surrogate variable. Direct visualization is highly desirable. Here, we achieve the direct measurement of barrier crossing trajectories by using optical microscopy to observe position and orientation changes of pairs of Ag nanoparticles, i. e. passing events, in an optical ring trap. A two-step mechanism similar to a bimolecular exchange reaction or the Michaelis-Menten scheme is revealed by analysis that combines detailed knowledge of each trajectory, a statistically significant number of repetitions of the passing events, and the driving force dependence of the process. We find that while the total event rate increases with driving force, this increase is due to an increase in the rate of encounters. There is no drive force dependence on the rate of barrier crossing because the key motion for the process involves a random (thermal) radial fluctuation of one particle allowing the other to pass. This simple experiment can readily be extended to study more complex barrier crossing processes by replacing the spherical metal nanoparticles with anisotropic ones or by creating more intricate optical trapping potentials.

Barriers and Facilitators of Mental Health Treatment-Seeking in U.S. Active Duty Soldiers With Sexual Assault Histories.

Science.gov (United States)

Zinzow, Heidi M; Britt, Thomas W; Pury, Cynthia L S; Jennings, Kristen; Cheung, Janelle H; Raymond, Mary Anne

2015-08-01

Despite significant mental health needs among sexual assault (SA) victims in the military, little is known about treatment-seeking patterns or factors associated with service use. This study examined service use behavior, barriers, and facilitators of mental health treatment-seeking in an active duty sample of 927 U.S. Army soldiers with mental health problems. SA victims (n = 113) did not differ from non-victims on barriers or facilitators after adjusting for demographic and mental health variables, with stigma rated as the largest barrier. Most SA victims (87.6%) had sought informal support and 59.3% had sought formal treatment. One third of treatment-seekers had dropped out of treatment. Multivariate logistic regression analyses identified several correlates of treatment-seeking among SA victims: Black race (OR = 7.57), SA during the military (OR = 4.34), positive treatment beliefs (OR = 2.22), social support for treatment (OR = 2.14), self-reliance (OR = 0.47), and stigma towards treatment seekers (OR = 0.43). Mental health symptoms were not associated with treatment seeking. Findings suggested that treatment-facilitating interventions should focus on improving recognition of mental health symptoms, altering perceptions related to self-reliance, and reducing stigma. Interventions should also enlist support for treatment-seeking from unit members, leaders, and significant others. © 2015 International Society for Traumatic Stress Studies.

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

Science.gov (United States)

Russo, Brendan J; Savolainen, Peter T

2018-08-01

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

Foreign exchange risk management : how are the largest non-financial companies in Norway managing their foreign exchange rate exposure?

OpenAIRE

Eriksen, Krister; Wedøe, Ola

2010-01-01

The purpose of this thesis is to investigate how the largest non-financial companies in Norway manage their foreign exchange rate exposure. This is investigated through the use of a survey distributed to a sample the largest non-financial firms in Norway. According to our results, the largest non-financial companies in Norway have a predefined strategy for managing foreign exchange risk, which is defined by the board of directors or by the management in the organisation. The companies’ mai...

Negotiation of intracellular membrane barriers by TAT-modified gold nanoparticles.

Science.gov (United States)

Krpetić, Zeljka; Saleemi, Samia; Prior, Ian A; Sée, Violaine; Qureshi, Rumana; Brust, Mathias

2011-06-28

This paper contributes to the debate on how nanosized objects negotiate membrane barriers inside biological cells. The uptake of peptide-modified gold nanoparticles by HeLa cells has been quantified using atomic emission spectroscopy. The TAT peptide from the HIV virus was singled out as a particularly effective promoter of cellular uptake. The evolution of the intracellular distribution of TAT-modified gold nanoparticles with time has been studied in detail by TEM and systematic image analysis. An unusual trend of particles disappearing from the cytosol and the nucleus and accumulating massively in vesicular bodies was observed. Subsequent release of the particles, both by membrane rupture and by direct transfer across the membrane boundary, was frequently found. Ultimately, near total clearing of particles from the cells occurred. This work provides support for the hypothesis that cell-penetrating peptides can enable small objects to negotiate membrane barriers also in the absence of dedicated transport mechanisms.

New Chicago-Indiana computer network will handle dataflow from world's largest scientific experiment

CERN Multimedia

2006-01-01

"Massive quantities of data will soon begin flowing from the largest scientific instrument ever built into an international netword of computer centers, including one operated jointly by the University of Chicago and Indiana University." (1,5 page)

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

Investigation of barrier cell and auxilliary heating in a tandem mirror. Annual progress report, October 1, 1979-September 30, 1980

International Nuclear Information System (INIS)

Kesner, J.; Emmert, G.A.; Howard, J.E.

1980-06-01

A number of areas relating to RF heating and thermal barrier formation in a tandem mirror have been investigated. The possibility of creating axisymmetric confinement through the use of sloshing-ions has been investigated. We have also suggested the complimentary concept of sloshing-electrons. Self-consistent thermal barrier formation has been studied and ion drift orbits in non-axisymmetric barriers are being investigated. The study of dynamic stabilization of the DCLC by RF fields has been extended to ω near 2 ω/sub ci/; significant stabilization is found. Fast and slow wave heating have been extensively studied using single particle theory. A new theory of relativistic ECH is under development

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)

γδ T cells in homeostasis and host defence of epithelial barrier tissues.

Science.gov (United States)

Nielsen, Morten M; Witherden, Deborah A; Havran, Wendy L

2017-12-01

Epithelial surfaces line the body and provide a crucial interface between the body and the external environment. Tissue-resident epithelial γδ T cells represent a major T cell population in the epithelial tissues and are ideally positioned to carry out barrier surveillance and aid in tissue homeostasis and repair. In this Review, we focus on the intraepithelial γδ T cell compartment of the two largest epithelial tissues in the body - namely, the epidermis and the intestine - and provide a comprehensive overview of the crucial contributions of intraepithelial γδ T cells to tissue integrity and repair, host homeostasis and protection in the context of the symbiotic relationship with the microbiome and during pathogen clearance. Finally, we describe epithelium-specific butyrophilin-like molecules and briefly review their emerging role in selectively shaping and regulating epidermal and intestinal γδ T cell repertoires.

Large-scale bleaching of corals on the Great Barrier Reef.

Science.gov (United States)

Hughes, T P; Kerry, J T; Simpson, T

2018-02-01

In 2015-2016, record temperatures triggered a pan-tropical episode of coral bleaching. In the southern hemisphere summer of March-April 2016, we used aerial surveys to measure the level of bleaching on 1,156 individual reefs throughout the 2,300 km length of the Great Barrier Reef, the world's largest coral reef system. The accuracy of the aerial scores was ground-truthed with detailed underwater surveys of bleaching at 260 sites (104 reefs), allowing us to compare aerial and underwater bleaching data with satellite-derived temperatures and with associated model predictions of bleaching. The severity of bleaching on individual reefs in 2016 was tightly correlated with the level of local heat exposure: the southernmost region of the Great Barrier Reef escaped with only minor bleaching because summer temperatures there were close to average. Gradients in nutrients and turbidity from inshore to offshore across the Great Barrier Reef had minimal effect on the severity of bleaching. Similarly, bleaching was equally severe on reefs that are open or closed to fishing, once the level of satellite-derived heat exposure was accounted for. The level of post-bleaching mortality, measured underwater after 7-8 months, was tightly correlated with the aerial scores measured at the peak of bleaching. Similarly, reefs with a high aerial bleaching score also experienced major shifts in species composition due to extensive mortality of heat-sensitive species. Reefs with low bleaching scores did not change in composition, and some showed minor increases in coral cover. Two earlier mass bleaching events occurred on the Great Barrier Reef in 1998 and 2002, that were less severe than 2016. In 2016, bleaching, compared to 42% in 2002 and 44% in 1998. Conversely, the proportion of reefs that were severely bleached (>60% of corals affected) was four times higher in 2016. The geographic footprint of each of the three events is distinctive, and matches satellite-derived sea surface

EVALUATION OF AMENDMENTS FOR MENDING THE INSITU REDOX MANIPULATION (ISRM) BARRIER

Energy Technology Data Exchange (ETDEWEB)

PETERSEN, S.W.

2006-02-07

evaluation of the ISRM performance data and barrier longevity assessment corroborate the observations and findings of the March 2004 TAT. The March 2004 TAT recommended the collection of new aquifer characterization data in combination with the interpretation of existing data to develop a conceptual model of aquifer heterogeneity to enable design of the most appropriate barrier mending system. The current TAT was convened to examine the most promising amendment that could be applied to mend the ISRM barrier. The Technical Assistance Team (TAT) performed the following activities: (1) Evaluate the most appropriate single or combination of chemical/biological amendments suitable for increasing the reductive capacity of the ISRM barrier; (2) Evaluate the most practicable means of introducing chemical/biological amendments in the target zones along the current BRM barrier; (3) Provide recommendations for laboratory treatability-testing protocol development to evaluate the type and delivery mechanisms of amendments in the current ISRM barrier location. Sections of this report present analyses and recommendations of potential amendments and delivery options to improve performance of the ISRM barrier. The report covers the spectrum of passive barrier mending to chemical and biological amendments that have been shown to perform more efficiently in more active remedial design approaches. Because DOE/RL is considering significant aquifer characterization studies as additional time and cost investment to mending the barrier, the TAT strongly recommends that DOE/RL conduct cost-benefit analyses of alternative designs to mend the barrier. In this way, the value and extent of characterization studies, compared to passive amendment delivery, compared to engineering redesign, can be quantitatively estimated for decision-making purposes.

Free-Energy Barrier of Filling a Spherical Cavity in the Presence of Line Tension: Implication to the Energy Barrier between the Cassie and Wenzel States on a Superhydrophobic Surface with Spherical Cavities.

Science.gov (United States)

Iwamatsu, Masao

2016-09-20

The free-energy barrier of filling a spherical cavity having an inner wall of various wettabilities is studied. The morphology and free energy of a lens-shaped droplet are determined from the minimum of the free energy. The effect of line tension on the free energy is also studied. Then, the equilibrium contact angle of the droplet is determined from the generalized Young's equation. By increasing the droplet volume within the spherical cavity, the droplet morphology changes from spherical with an equilibrium contact angle of 180° to a lens with a convex meniscus, where the morphological complete drying transition occurs. By further increasing the droplet volume, the meniscus changes from convex to concave. Then, the lens-shaped droplet with concave meniscus spreads over the whole inner wall, resulting in an equilibrium contact angle of 0° to leave a spherical bubble, where the morphological complete wetting transition occurs. Finally, the whole cavity is filled with liquid. The free energy shows a barrier from complete drying to complete wetting as a function of droplet volume, which corresponds to the energy barrier between the Cassie and Wenzel states of the superhydrophobic surface with spherical cavities. The free-energy maximum occurs when the meniscus of the droplet becomes flat, and it is given by an analytic formula. The effect of line tension is expressed by the scaled line tension, and this effect is largest at the free-energy maximum. The positive line tension increases the free-energy maximum, which thus increases the stability of the Cassie superhydrophobic state, whereas the negative line tension destabilizes the superhydrophobic state.

Economic alternatives for containment barriers

International Nuclear Information System (INIS)

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

1997-01-01

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

Dynamical barrier for the formation of solitary waves in discrete lattices

Energy Technology Data Exchange (ETDEWEB)

Kevrekidis, P.G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003 (United States)], E-mail: kevrekid@math.umass.edu; Espinola-Rocha, J.A. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003 (United States); Drossinos, Y. [European Commission, Joint Research Centre, I-21020 Ispra (Vatican City State, Holy See,) (Italy); School of Mechanical and Systems Engineering, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU (United Kingdom); Stefanov, A. [Department of Mathematics, University of Kansas, 1460 Jayhawk Blvd., Lawrence, KS 66045-7523 (United States)

2008-03-24

We consider the problem of the existence of a dynamical barrier of 'mass' that needs to be excited on a lattice site to lead to the formation and subsequent persistence of localized modes for a nonlinear Schroedinger lattice. We contrast the existence of a dynamical barrier with its absence in the static theory of localized modes in one spatial dimension. We suggest an energetic criterion that provides a sufficient, but not necessary, condition on the amplitude of a single-site initial condition required to form a solitary wave. We show that this effect is not one-dimensional by considering its two-dimensional analog. The existence of a sufficient condition for the excitation of localized modes in the non-integrable, discrete, nonlinear Schroedinger equation is compared to the dynamics of excitations in the integrable, both discrete and continuum, version of the nonlinear Schroedinger equation.

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...

Athermal avalanche in bilayer superconducting nanowire single-photon detectors

Energy Technology Data Exchange (ETDEWEB)

Verma, V. B., E-mail: verma@nist.gov; Lita, A. E.; Stevens, M. J.; Mirin, R. P.; Nam, S. W. [National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305 (United States)

2016-03-28

We demonstrate that two superconducting nanowires separated by a thin insulating barrier can undergo an avalanche process. In this process, Joule heating caused by a photodetection event in one nanowire and the associated production of athermal phonons which are transmitted through the barrier cause the transition of the adjacent nanowire from the superconducting to the normal state. We show that this process can be utilized in the fabrication of superconducting nanowire single photon detectors to improve the signal-to-noise ratio, reduce system jitter, maximize device area, and increase the external efficiency over a very broad range of wavelengths. Furthermore, the avalanche mechanism may provide a path towards a superconducting logic element based on athermal gating.

Opportunities for biodiversity gains under the world’s largest reforestation programme

OpenAIRE

Hua, Fangyuan; Wang, Xiaoyang; Zheng, Xinlei; Fisher, Brendan; Wang, Lin; Zhu, Jianguo; Tang, Ya; Yu, Douglas W.; Wilcove, David S.

2016-01-01

Reforestation is a critical means of addressing the environmental and social problems of deforestation. China’s Grain-for-Green Program (GFGP) is the world’s largest reforestation scheme. Here we provide the first nationwide assessment of the tree composition of GFGP forests and the first combined ecological and economic study aimed at understanding GFGP’s biodiversity implications. Across China, GFGP forests are overwhelmingly monocultures or compositionally simple mixed forests. Focusing on...

Barrier rf systems in synchrotrons

International Nuclear Information System (INIS)

Bhat, Chandra M.

2004-01-01

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

ECONOMIC EXPERIENCES OF SINGLE MOTHERS IN BHAMBAYI, KWAZULU-NATAL, SOUTH AFRICA

Directory of Open Access Journals (Sweden)

Raniga, Tanusha

2014-10-01

Full Text Available Women living in low-income communities often initiate livelihood activities as a means to support themselves and their families. Even though these small-scale livelihood activities supplement the household income, they are insufficient to lift single mothers out of poverty. This study explores the economic experiences of 25 single mothers who embarked on individual livelihood activities. Using feminist theory, the paper presents their biographical profile and discusses two key themes, namely institutional barriers leading to economic insecurities, and the strengths and limitations of social networks. The paper concludes with some considerations for harnessing the valuable contributions made by single mothers.

H + H2 reaction barrier: A fixed-node quantum Monte Carlo study

International Nuclear Information System (INIS)

Barnett, R.N.; Reynolds, P.J.; Lester, W.A. Jr.

1985-01-01

The classical barrier height for the H+H 2 exchange reaction, as well as the energies at two other points along the reaction path, are calculated using fixed-node quantum Monte Carlo (FNQMC). Several single-determinant importance functions are used at the saddle point in order to relate the quality of the importance function to the accuracy and precision of the final result. The computed barrier is an upper bound since the energy of H and of H 2 is obtained exactly by FNQMC. Our best upper bound (9.70 +- 0.13 kcal/mol) has a mean within 0.1 kcal/mol of the presumed exact value. This best bound is obtained with a single determinant, double-zeta basis importance function. Contrary to experience with expansion methods, it is found that an importance function with a basis set of near Hartree--Fock quality, as well as one derived from a spin-unrestricted SCF calculation, are among the least efficient and least accurate of the importance functions used. Specifically, a nodal surface appearing in the lowest energy molecular orbital in these functions apparently increases the FNQMC energy. The FNQMC energy at the two other points along the reaction path is found to agree with the most accurate CI results of Liu to within statistical error

Subsurface barrier verification technologies, informal report

International Nuclear Information System (INIS)

Heiser, J.H.

1994-06-01

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

Rehabilitation of the 6 largest hydropower plants in the Republic of Macedonia

International Nuclear Information System (INIS)

Chingoski, Vlatko; Savevski, Vasil

2004-01-01

In 1998, ESM (Electric Power Co. of Macedonia) received a loan from the International Bank for Reconstruction and Development (IBRD - The World bank) for the cost of the Power System Improvement Project, major part of which is the partial rehabilitation of the six largest HPPs in the Republic of Macedonia. Rehabilitation and life extension of these six largest hydro power plants is given the highest priority in the whole Power System Improvement Project mainly because these HPPs are, in general, fairly old, older than most of the thermal generation capacity and because a significant part of their equipment is wearing out, or is now obsolete with spare parts difficult to obtain. Furthermore, these plants play a vital role in the Macedonian Power System, providing peaking capacity, reserve capacity and frequency control. With the realization of this project, greater hydropower production is expected. It is also expected that HPPs will become a more vital part of the Macedonian Power System, which is also beneficial from an environmental aspect, due to greater usage of renewable energy resources in the country. (Original)

Fluctuations in Schottky barrier heights

International Nuclear Information System (INIS)

Mahan, G.D.

1984-01-01

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

Spectral multitude and spectral dynamics reflect changing conjugation length in single molecules of oligophenylenevinylenes

KAUST Repository

Kobayashi, Hiroyuki; Tsuchiya, Kousuke; Ogino, Kenji; Vacha, Martin

2012-01-01

Single-molecule study of phenylenevinylene oligomers revealed distinct spectral forms due to different conjugation lengths which are determined by torsional defects. Large spectral jumps between different spectral forms were ascribed to torsional flips of a single phenylene ring. These spectral changes reflect the dynamic nature of electron delocalization in oligophenylenevinylenes and enable estimation of the phenylene torsional barriers. © 2012 The Owner Societies.

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...

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

Science.gov (United States)

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

2016-01-01

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

FANCJ couples replication past natural fork barriers with maintenance of chromatin structure.

Science.gov (United States)

Schwab, Rebekka A; Nieminuszczy, Jadwiga; Shin-ya, Kazuo; Niedzwiedz, Wojciech

2013-04-01

Defective DNA repair causes Fanconi anemia (FA), a rare childhood cancer-predisposing syndrome. At least 15 genes are known to be mutated in FA; however, their role in DNA repair remains unclear. Here, we show that the FANCJ helicase promotes DNA replication in trans by counteracting fork stalling on replication barriers, such as G4 quadruplex structures. Accordingly, stabilization of G4 quadruplexes in ΔFANCJ cells restricts fork movements, uncouples leading- and lagging-strand synthesis and generates small single-stranded DNA gaps behind the fork. Unexpectedly, we also discovered that FANCJ suppresses heterochromatin spreading by coupling fork movement through replication barriers with maintenance of chromatin structure. We propose that FANCJ plays an essential role in counteracting chromatin compaction associated with unscheduled replication fork stalling and restart, and suppresses tumorigenesis, at least partially, in this replication-specific manner.

Richards Barrier LA Reference Design Feature Evaluation

International Nuclear Information System (INIS)

N.E. Kramer

1999-01-01

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

Ownership, financing, and management strategies of the ten largest for-profit nursing home chains in the United States.

Science.gov (United States)

Harrington, Charlene; Hauser, Clarilee; Olney, Brian; Rosenau, Pauline Vaillancourt

2011-01-01

This study examined the ownership, financing, and management strategies of the 10 largest for-profit nursing home chains in the United States, including the four largest chains purchased by private equity corporations. Descriptive data were collected from Internet searches, company reports, and other sources for the decade 1998-2008. Since 1998, the largest chains have made many changes in their ownership and structure, and some have converted from publicly traded companies to private ownership. This study shows the increasing complexity of corporate nursing home ownership and the lack of public information about ownership and financial status. The chains have used strategies to maximize shareholder and investor value that include increasing Medicare revenues, occupancy rates, and company diversification, establishing multiple layers of corporate ownership, developing real estate investment trusts, and creating limited liability companies. These strategies enhance shareholder and investor profits, reduce corporate taxes, and reduce liability risk. There is a need for greater transparency in ownership and financial reporting and for more government oversight of the largest for-profit chains, including those owned by private equity companies.

Skin barrier composition

International Nuclear Information System (INIS)

Osburn, F.G.

1985-01-01

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

Skin barrier composition

Energy Technology Data Exchange (ETDEWEB)

Osburn, F G

1985-06-12

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

Ring distributions leading to species formation: a global topographic analysis of geographic barriers associated with ring species.

Science.gov (United States)

Monahan, William B; Pereira, Ricardo J; Wake, David B

2012-03-12

In the mid 20th century, Ernst Mayr and Theodosius Dobzhansky championed the significance of circular overlaps or ring species as the perfect demonstration of speciation, yet in the over 50 years since, only a handful of such taxa are known. We developed a topographic model to evaluate whether the geographic barriers that favor processes leading to ring species are common or rare, and to predict where other candidate ring barriers might be found. Of the 952,147 geographic barriers identified on the planet, only about 1% are topographically similar to barriers associated with known ring taxa, with most of the likely candidates occurring in under-studied parts of the world (for example, marine environments, tropical latitudes). Predicted barriers separate into two distinct categories: (i) single cohesive barriers (barriers - formed by groups of barriers (each 184,000 to 1.7 million km2) in close geographic proximity (totaling 1.9 to 2.3 million km2) - associated with taxa that differentiate at larger spatial scales (birds: Phylloscopus trochiloides and Larus (sp. argentatus and fuscus)). When evaluated globally, we find a large number of cohesive barriers that are topographically similar to those associated with known ring taxa. Yet, compared to cohesive barriers, an order of magnitude fewer composite barriers are similar to those that favor ring divergence in species with higher dispersal. While these findings confirm that the topographic conditions that favor evolutionary processes leading to ring speciation are, in fact, rare, they also suggest that many understudied natural systems could provide valuable demonstrations of continuous divergence towards the formation of new species. Distinct advantages of the model are that it (i) requires no a priori information on the relative importance of features that define barriers, (ii) can be replicated using any kind of continuously distributed environmental variable, and (iii) generates spatially explicit hypotheses of

Barriers for recess physical activity

DEFF Research Database (Denmark)

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

2014-01-01

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

Existing sustainable renovation concepts for single-family houses

DEFF Research Database (Denmark)

Tommerup, Henrik M.; Vanhoutteghem, Lies; Svendsen, Svend

2010-01-01

In the Nordic Innovation Centre Project, SuccessFamilies, the main objective is to change the business environment in order to speed up the implementation of sustainable renovation of single-family houses – proposing new service concepts that will combine both the technical solutions, financing...... with individual solutions, traditional warehouses ”do-it-yourself-shops” and some actors marketing single products. To speed up the implementation of sustainable renovation of single-family houses there is a great need for full-service packages. Existing technical renovation concepts, typically focusing...... services as well as other promoting issues to overcome the behavioural, organizational, legal and social barriers that exist in sustainable renovation. A starting point for such a change has been to get an overview of the existing sustainable renovation concepts, i.e. full-service concepts and technical...

Nonlinear behaviors in a pulsed dielectric barrier discharge at atmospheric pressure

Energy Technology Data Exchange (ETDEWEB)

Zhang Jiao; Wang Yanhui, E-mail: wangyh@dlut.edu.cn; Wang Dezhen

2011-08-01

In this paper, the temporal nonlinear behaviors of pulsed dielectric barrier discharge in atmospheric helium are studied numerically by a one-dimensional fluid model. The results show that the common single-period pulsed discharge with two current pulses per single voltage pulse can take place over a broad parameter range. The rising and falling times of the voltage pulse can affect the discharge characteristics greatly. When the discharge is ignited by a pulse voltage with long rising and falling times, a single-period pulsed discharge with multiple current peaks can be observed. Under appropriate rising and falling times of the voltage pulse, a stable period-two discharge can occur over wide frequency and voltage ranges. Also this period-two discharge can exhibit different current and voltage characteristics with changing the duty cycle. With other parameters fixed, the pulsed DBD could be driven to chaos through period-doubling route by increasing either the falling time or the frequency of voltage pulse.

SSC RIAR is the largest centre of research reactors

International Nuclear Information System (INIS)

Kalygin, V.V.

1997-01-01

The State Scientific Centre (SSC) ''Research Institute of Atomic Reactors'' (RIAR) is situated 100 km to the south-east from Moscow, in Dimitrovgrad, the Volga Region of the Russian Federation. SSC RIAR is the largest centre of research reactors in Russia. At present there are 5 types of reactor facilities in operation, including two NPP. One of the main tasks the Centre is the investigations on safety increase for power reactors. Broad international connections are available at the Institute. On the basis of the SSC RIAR during 3 years work has been done on the development of the branch training centre (TC) for the training of operation personnel of research and pilot reactors in Russia. (author). 3 tabs

SSC RIAR is the largest centre of research reactors

Energy Technology Data Exchange (ETDEWEB)

Kalygin, V V [State Scientific Centre, Research Inst. of Atomic Reactors (Russian Federation)

1997-10-01

The State Scientific Centre (SSC) ``Research Institute of Atomic Reactors`` (RIAR) is situated 100 km to the south-east from Moscow, in Dimitrovgrad, the Volga Region of the Russian Federation. SSC RIAR is the largest centre of research reactors in Russia. At present there are 5 types of reactor facilities in operation, including two NPP. One of the main tasks the Centre is the investigations on safety increase for power reactors. Broad international connections are available at the Institute. On the basis of the SSC RIAR during 3 years work has been done on the development of the branch training centre (TC) for the training of operation personnel of research and pilot reactors in Russia. (author). 3 tabs.

Self-regulation of turbulence bursts and transport barriers

International Nuclear Information System (INIS)

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

2013-01-01

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

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.

Hospital Prices Increase in California, Especially Among Hospitals in the Largest Multi-hospital Systems

Directory of Open Access Journals (Sweden)

Glenn A. Melnick PhD

2016-06-01

Full Text Available A surge in hospital consolidation is fueling formation of ever larger multi-hospital systems throughout the United States. This article examines hospital prices in California over time with a focus on hospitals in the largest multi-hospital systems. Our data show that hospital prices in California grew substantially (+76% per hospital admission across all hospitals and all services between 2004 and 2013 and that prices at hospitals that are members of the largest, multi-hospital systems grew substantially more (113% than prices paid to all other California hospitals (70%. Prices were similar in both groups at the start of the period (approximately $9200 per admission. By the end of the period, prices at hospitals in the largest systems exceeded prices at other California hospitals by almost $4000 per patient admission. Our study findings are potentially useful to policy makers across the country for several reasons. Our data measure actual prices for a large sample of hospitals over a long period of time in California. California experienced its wave of consolidation much earlier than the rest of the country and as such our findings may provide some insights into what may happen across the United States from hospital consolidation including growth of large, multi-hospital systems now forming in the rest of the rest of the country.

Cryogenic Barrier Demonstration Project. Final report

Energy Technology Data Exchange (ETDEWEB)

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

2000-03-01

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

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

Tunneling rates in electron transport through double-barrier molecular junctions in a scanning tunneling microscope.

Science.gov (United States)

Nazin, G V; Wu, S W; Ho, W

2005-06-21

The scanning tunneling microscope enables atomic-scale measurements of electron transport through individual molecules. Copper phthalocyanine and magnesium porphine molecules adsorbed on a thin oxide film grown on the NiAl(110) surface were probed. The single-molecule junctions contained two tunneling barriers, vacuum gap, and oxide film. Differential conductance spectroscopy shows that electron transport occurs via vibronic states of the molecules. The intensity of spectral peaks corresponding to the individual vibronic states depends on the relative electron tunneling rates through the two barriers of the junction, as found by varying the vacuum gap tunneling rate by changing the height of the scanning tunneling microscope tip above the molecule. A simple, sequential tunneling model explains the observed trends.

A general approach to break the concentration barrier in single-molecule imaging

KAUST Repository

Loveland, Anna B.

2012-09-09

Single-molecule fluorescence imaging is often incompatible with physiological protein concentrations, as fluorescence background overwhelms an individual molecule\\'s signal. We solve this problem with a new imaging approach called PhADE (PhotoActivation, Diffusion and Excitation). A protein of interest is fused to a photoactivatable protein (mKikGR) and introduced to its surface-immobilized substrate. After photoactivation of mKikGR near the surface, rapid diffusion of the unbound mKikGR fusion out of the detection volume eliminates background fluorescence, whereupon the bound molecules are imaged. We labeled the eukaryotic DNA replication protein flap endonuclease 1 with mKikGR and added it to replication-competent Xenopus laevis egg extracts. PhADE imaging of high concentrations of the fusion construct revealed its dynamics and micrometer-scale movements on individual, replicating DNA molecules. Because PhADE imaging is in principle compatible with any photoactivatable fluorophore, it should have broad applicability in revealing single-molecule dynamics and stoichiometry of macromolecular protein complexes at previously inaccessible fluorophore concentrations. © 2012 Nature America, Inc. All rights reserved.

Barriers to evidence-based medicine: a systematic review.

Science.gov (United States)

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

2014-12-01

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

Market and Policy Barriers to Energy Storage Deployment

Energy Technology Data Exchange (ETDEWEB)

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

2013-09-01

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

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.

Electrical insulator assembly with oxygen permeation barrier

Science.gov (United States)

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

1994-01-01

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

Proton emission with a screened electrostatic barrier

Energy Technology Data Exchange (ETDEWEB)

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

2017-08-15

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

A marine heatwave drives massive losses from the world’s largest seagrass carbon stocks

KAUST Repository

Arias-Ortiz, Ariane; Serrano, Oscar; Masqué , Pere; Lavery, P. S.; Mueller, U.; Kendrick, G. A.; Rozaimi, M.; Esteban, A.; Fourqurean, J. W.; Marbà , N.; Mateo, M. A.; Murray, K.; Rule, M. J.; Duarte, Carlos M.

2018-01-01

Seagrass ecosystems contain globally significant organic carbon (C) stocks. However, climate change and increasing frequency of extreme events threaten their preservation. Shark Bay, Western Australia, has the largest C stock reported for a seagrass

Spatio-temporal resolved diagnostics of the single filament barrier discharge in air

International Nuclear Information System (INIS)

Wagner, H.E.; Brandenburg, R.; Michel, P.; Kozlov, K.V.

2001-01-01

First experimental results on the spatio-temporal development of single filaments of DBDs in dry air at atmospheric pressure are presented. The measurements allow a detailed visualisation and interpretation of the streamer development. In combination with the kinetic model they are used to get information on the spatiotemporal development of the reduced field-strength E/n, too

Lamellar granule secretion starts before the establishment of tight junction barrier for paracellular tracers in mammalian epidermis.

Directory of Open Access Journals (Sweden)

Akemi Ishida-Yamamoto

Full Text Available Defects in epidermal barrier function and/or vesicular transport underlie severe skin diseases including ichthyosis and atopic dermatitis. Tight junctions (TJs form a single layered network in simple epithelia. TJs are important for both barrier functions and vesicular transport. Epidermis is stratified epithelia and lamellar granules (LGs are secreted from the stratum granulosum (SG in a sequential manner. Previously, continuous TJs and paracellular permeability barriers were found in the second layer (SG2 of SG in mice, but their fate and correlation with LG secretion have been poorly understood. We studied epidermal TJ-related structures in humans and in mice and found occludin/ZO-1 immunoreactive multilayered networks spanning the first layer of SG (SG1 and SG2. Paracellular penetration tracer passed through some TJs in SG2, but not in SG1. LG secretion into the paracellular tracer positive spaces started below the level of TJs of SG1. Our study suggests that LG-secretion starts before the establishment of TJ barrier in the mammalian epidermis.

Fusion barrier characteristics of actinides

Science.gov (United States)

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

2018-03-01

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

SKYSHIN: A computer code for calculating radiation dose over a barrier

International Nuclear Information System (INIS)

Atwood, C.L.; Boland, J.R.; Dickman, P.T.

1986-11-01

SKYSHIN is a computer code for calculating the radioactive dose (mrem), when there is a barrier between the point source and the receptor. The two geometrical configurations considered are: the source and receptor separated by a rectangular wall, and the source at the bottom of a cylindrical hole in the ground. Each gamma ray traveling over the barrier is assumed to be scattered at a single point. The dose to a receptor from such paths is numerically integrated for the total dose, with symmetry used to reduce the triple integral to a double integral. The buildup factor used along a straight line through air is based on published data, and extrapolated in a stable way to low energy levels. This buildup factor was validated by comparing calculated and experimental line-of-sight doses. The entire code shows good agreement to limited field data. The code runs on a CDC or on a Vax computer, and could be modified easily for others

Addressing barriers to low carbon energy

International Nuclear Information System (INIS)

Berry, Fiona; Dunstan, Chris

2012-01-01

Full text: Two energy solutions gaining attention are cogeneration and trigeneration, mostly fuelled by natural gas, although other renewable sources can be used, such as sewage, agricultural waste and municipal waste. Trigeneration has become increasingly popular in Australia's urban centres as a relatively cost-effective means to cut the carbon-intensity of energy supply by more than half compared to traditional coal- fired electricity. Some examples of trigeneration projects include the City of Sydney's planned 360 megawatt trigeneration networks by 2030, the University of Technology Sydney's campus master plan and the six star Green Star Commonwealth Bank Place building in Sydney. Trigeneration and cogeneration can present opportunities such as addressing the issue of rising peak demand, which is a major driver for the current $9 billion per annum of network infrastructure spending. They can also face barriers. For example, depending on the current state of the network, additional network costs can be required to accommodate trigeneration. Furthermore, under the current National Electricity Market regulations and conventions, challenges do exist to timely and financially viable connection to the grid. Here we present two examples of barriers to trigeneration and cogeneration and solutions being considered and implemented. The University of Technology Sydney campus master plan is underway, with approximately 100,000sq.m of floor area being built by 2019 and includes plans for trigeneration. During the master planning phase of development, the university considered small trigeneration units in individual buildings in order to reduce the carbon intensity of electricity supply and deliver high ratings under Green Star ratings. When considering connecting trigeneration with the grid at multiple buildings on an individual basis, a number of barriers were encountered by UTS. The largest barrier was appropriate charging for connecting to and using the grid. However

The largest Silurian vertebrate and its palaeoecological implications

Science.gov (United States)

Choo, Brian; Zhu, Min; Zhao, Wenjin; Jia, Liaotao; Zhu, You'an

2014-01-01

An apparent absence of Silurian fishes more than half-a-metre in length has been viewed as evidence that gnathostomes were restricted in size and diversity prior to the Devonian. Here we describe the largest pre-Devonian vertebrate (Megamastax amblyodus gen. et sp. nov.), a predatory marine osteichthyan from the Silurian Kuanti Formation (late Ludlow, ~423 million years ago) of Yunnan, China, with an estimated length of about 1 meter. The unusual dentition of the new form suggests a durophagous diet which, combined with its large size, indicates a considerable degree of trophic specialisation among early osteichthyans. The lack of large Silurian vertebrates has recently been used as constraint in palaeoatmospheric modelling, with purported lower oxygen levels imposing a physiological size limit. Regardless of the exact causal relationship between oxygen availability and evolutionary success, this finding refutes the assumption that pre-Emsian vertebrates were restricted to small body sizes. PMID:24921626

Programmer's description of the Barrier Data Base

International Nuclear Information System (INIS)

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

1976-12-01

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

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.

THE MASS OF (4) VESTA DERIVED FROM ITS LARGEST GRAVITATIONAL EFFECTS

International Nuclear Information System (INIS)

Kuzmanoski, Mike; Novakovic, Bojan; Apostolovska, Gordana

2010-01-01

In this paper, we present a recalculated value of the mass of (4) Vesta, derived from its largest gravitational perturbations on selected asteroids during their mutual close encounters. This was done by using a new method for mass determination, which is based on the linking of pre-encounter observations to the orbit determined from post-encounter ones. The estimated weighted mean of the mass of (4) Vesta is (1.300 ± 0.001) x 10 -10 M sun .

Tunnelling through a Gaussian random barrier

International Nuclear Information System (INIS)

Bezak, Viktor

2008-01-01

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

Pressure effects on single chain magnets

Energy Technology Data Exchange (ETDEWEB)

Mito, M. E-mail: mitoh@elcs.kyutech.ac.jp; Shindo, N.; Tajiri, T.; Deguchi, H.; Takagi, S.; Miyasaka, H.; Yamashita, M.; Clerac, R.; Coulon, C

2004-05-01

Pressure effects on a single chain magnet [Mn{sub 2}(saltmen){sub 2}Ni(pao){sub 2}(py){sub 2}](ClO{sub 4}){sub 2} (saltmen{sup 2-}=N,N'-(1,1,2,2-tetramethylethylene)bis(salicylideneiminate), and pao{sup -}=pyridine-2-aldoximate) have been investigated through AC magnetic measurements under pressure (P). The slow relaxation of the magnetization depends on pressure. Both the blocking temperature (T{sub B}) and energy barrier ({delta}) increase by pressurization, and those enhancements saturate at around P=7 kbar.

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

Examining the rudimentary steps of the oxygen reduction reaction on single-atomic Pt using Ti-based non-oxide supports

DEFF Research Database (Denmark)

Tak, Young Joo; Yang, Sungeun; Lee, Hyunjoo

2018-01-01

C(100)-supported single Pt atoms. The O2 and OOH* dissociation processes on Pt/TiN(100) are determined to be non-activated (i.e. "barrier-less" dissociation) while an activation energy barrier of 0.19 and 0.51eV is found for these dissociation processes on Pt/TiC(100), respectively. Moreover, the series...

Market barriers to welfare product innovations

NARCIS (Netherlands)

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

2006-01-01

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

TAMR effect in the tunneling through monocrystalline GaAs barriers; TAMR-Effekt beim Tunneln durch einkristalline GaAs-Barrieren

Energy Technology Data Exchange (ETDEWEB)

Lobenhofer, Michael

2013-01-28

Within the scope of this thesis the TAMR-effect in magnetic tunnel junctions with a single-crystalline GaAs-barrier was investigated. As ferromagnetic electrodes Fe-, FeCo- and FePt-layers were used. The measured TAMR-effect was investigated with respect to its behaviour towards changes in external Parameters, like the applied voltage, the temperature and the external magnetic field. The physical origin of the effect was attributed to the interaction of Rashba- and Dresselhaus-Spin-Orbit-coupling inside the tunnelling barrier and at the metal/semiconductor-interfaces.

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.

Key U.S.-built part fails during testing for world's largest particle collider

CERN Multimedia

2007-01-01

"Scientists are scrambling to redesign a key U.S.-built part that broke "with a loud bang and a cloud of dust" during a high-pressure test for the world's largest particle physics collider that is supposed to start up in November, officials sais Tuesday." (1,5 page)

Effects of barrier composition and electroplating chemistry on adhesion and voiding in copper/dielectric diffusion barrier films

Energy Technology Data Exchange (ETDEWEB)

Birringer, Ryan P.; Dauskardt, Reinhold H. [Department of Materials Science and Engineering, Stanford University, Durand Building, Stanford, California 94305-4034 (United States); Shaviv, Roey [Novellus Systems Inc., 4000 North First Street, San Jose, California 95134 (United States); Geiss, Roy H.; Read, David T. [National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305 (United States)

2011-08-15

The effects of electroplating chemistry and dielectric diffusion barrier composition on copper voiding and barrier adhesion are reported. Adhesion was quantified using the four-point bend thin film adhesion technique, and voiding in the Cu films was quantified using scanning electron microscopy. A total of 12 different film stacks were investigated, including three different Cu electroplating chemistries and four different barrier materials (SiN, N-doped SiC, O-doped SiC, and dual-layer SiC). Both plating chemistry and barrier composition have a large effect on interface adhesion and voiding in the Cu film. X-ray photoelectron spectroscopy was used to investigate the segregation of Cu electroplating impurities, such as S and Cl, to the Cu/barrier interface. Secondary ion mass spectrometry was used to quantify oxygen content at the Cu/barrier interface in a subset of samples. This interface oxygen content is correlated with measured adhesion values.

Combined Effects of JP-8 Fuel and Ceramic Thermal Barrier Coatings on the Performance and Emissions of a DI Diesel Engine

National Research Council Canada - National Science Library

Klett, David

1999-01-01

.... The experiments were conducted on a Ricardo Hydra single-cylinder DI diesel engine. Thin ceramic thermal barrier coatings were applied to various combustion chamber surfaces including the piston crown, cylinder head, and cylinder liner...

Measuring solvent barrier properties of paper

International Nuclear Information System (INIS)

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

2012-01-01

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

Single blinded, randomized, placebo-controlled study on the effects of ciclosporin on cutaneous barrier function and immunological response in atopic beagles.

Science.gov (United States)

White, Amelia G; Santoro, Domenico; Ahrens, Kim; Marsella, Rosanna

2018-03-01

Ciclosporin (CsA) is a common treatment for canine atopic dermatitis (cAD). cAD is a very common skin disease with a multifactorial pathogenesis due to complex interactions between the host and the environment. The purpose of this study was to describe the physical and immunological effects of CsA in cAD using a canine model of AD. Fourteen beagles were enrolled; seven received CsA orally every 24 h for 28 days, and seven received placebo. All dogs were exposed to relevant allergens, house dust mite solution, one day prior to treatment and once weekly thereafter for 28 consecutive days. Canine atopic dermatitis extent and severity index-03 (CADESI-03) and skin biopsies were performed on day 0, 14, and 28. Quantitative RT-PCR was used to determine levels of cutaneous cytokines and barrier function markers. Indirect immunofluorescence was used to determine protein expression and distribution of nuclear messengers, barrier function and inflammatory [thymic stromal lymphopoietin (TSLP)] markers. The data were tested for normality and then the upaired two samples Student's t-test and the repeated measurements ANOVA, followed by the Dunnett's Multiple Comparison Test as post-hoc analysis, were performed. A P value of immunologic milieu or barrier markers despite evident improvement of physical signs in the treatment group. Although this study confirmed the usefulness of CsA for the treatment of cAD, a clear involvement of CsA on some of the currently known immunological alterations present in cAD was not determined. However, it is important to note that there was no measurable exacerbation of skin barrier dysfunction secondary to CsA administration in this model. Copyright © 2018 Elsevier B.V. All rights reserved.

Enablers of and barriers to abortion training.

Science.gov (United States)

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

2013-06-01

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

Spatial characterization of the edge barrier in wide superconducting films

Science.gov (United States)

Sivakov, A. G.; Turutanov, O. G.; Kolinko, A. E.; Pokhila, A. S.

2018-03-01

The current-induced destruction of superconductivity is discussed in wide superconducting thin films, whose width is greater than the magnetic field penetration depth, in weak magnetic fields. Particular attention is paid to the role of the boundary potential barrier (the Bin-Livingston barrier) in critical state formation and detection of the edge responsible for this critical state with different mutual orientations of external perpendicular magnetic field and transport current. Critical and resistive states of the film were visualized using the space-resolving low-temperature laser scanning microscopy (LTLSM) method, which enables detection of critical current-determining areas on the film edges. Based on these observations, a simple technique was developed for investigation of the critical state separately at each film edge, and for the estimation of residual magnetic fields in cryostats. The proposed method only requires recording of the current-voltage characteristics of the film in a weak magnetic field, thus circumventing the need for complex LTLSM techniques. Information thus obtained is particularly important for interpretation of studies of superconducting film single-photon light emission detectors.

Decomposition mechanism of trichloroethylene based on by-product distribution in the hybrid barrier discharge plasma process

Energy Technology Data Exchange (ETDEWEB)

Han, Sang-Bo [Industry Applications Research Laboratory, Korea Electrotechnology Research Institute, Changwon, Kyeongnam (Korea, Republic of); Oda, Tetsuji [Department of Electrical Engineering, The University of Tokyo, Tokyo 113-8656 (Japan)

2007-05-15

The hybrid barrier discharge plasma process combined with ozone decomposition catalysts was studied experimentally for decomposing dilute trichloroethylene (TCE). Based on the fundamental experiment for catalytic activities on ozone decomposition, MnO{sub 2} was selected for application in the main experiments for its higher catalytic abilities than other metal oxides. A lower initial TCE concentration existed in the working gas; the larger ozone concentration was generated from the barrier discharge plasma treatment. Near complete decomposition of dichloro-acetylchloride (DCAC) into Cl{sub 2} and CO{sub x} was observed for an initial TCE concentration of less than 250 ppm. C=C {pi} bond cleavage in TCE gave a carbon single bond of DCAC through oxidation reaction during the barrier discharge plasma treatment. Those DCAC were easily broken in the subsequent catalytic reaction. While changing oxygen concentration in working gas, oxygen radicals in the plasma space strongly reacted with precursors of DCAC compared with those of trichloro-acetaldehyde. A chlorine radical chain reaction is considered as a plausible decomposition mechanism in the barrier discharge plasma treatment. The potential energy of oxygen radicals at the surface of the catalyst is considered as an important factor in causing reactive chemical reactions.

Single Top quark production cross-section measurements using the ATLAS detector at the LHC

CERN Document Server

Jimenez Pena, Javier; The ATLAS collaboration

2018-01-01

Measurements of single top-quark production in proton-proton collisions are presented based on the 13 TeV and 8 TeV ATLAS datasets. In the leading order process, a W-boson is exchanged in the t-channel. The cross-section for the production of single top-quarks and single antitop-quarks, their ratio, as well as differential cross-section measurements are also reported. Measurements of the inclusive and differential cross-sections for the production of a single top quark in association with a W-boson, the second largest single top production mode are also presented. Evidence for the s-channel single top-quark production in the 8 TeV dataset is presented. Finally, the first measurement of the tZq electroweak production is presented. All measurements are compared to state-of-the art theoretical calculations. (On behalf of the ATLAS collaboration)

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....

Effects of single and repeated exposure to biocidal active substances on the barrier function of the skin in vitro

NARCIS (Netherlands)

Buist, H.E.; Sandt, J.J.M. van de; Burgsteden, J.A. van; Heer, C. de

2005-01-01

The dermal route of exposure is important in worker exposure to biocidal products. Many biocidal active substances which are used on a daily basis may decrease the barrier function of the skin to a larger extent than current risk assessment practice addresses, due to possible skin effects of

UK Iatrogenic Creutzfeldt-Jakob disease: investigating human prion transmission across genotypic barriers using human tissue-based and molecular approaches.

Science.gov (United States)

Ritchie, Diane L; Barria, Marcelo A; Peden, Alexander H; Yull, Helen M; Kirkpatrick, James; Adlard, Peter; Ironside, James W; Head, Mark W

2017-04-01

Creutzfeldt-Jakob disease (CJD) is the prototypic human prion disease that occurs most commonly in sporadic and genetic forms, but it is also transmissible and can be acquired through medical procedures, resulting in iatrogenic CJD (iCJD). The largest numbers of iCJD cases that have occurred worldwide have resulted from contaminated cadaveric pituitary-derived human growth hormone (hGH) and its use to treat primary and secondary growth hormone deficiency. We report a comprehensive, tissue-based and molecular genetic analysis of the largest series of UK hGH-iCJD cases reported to date, including in vitro kinetic molecular modelling of genotypic factors influencing prion transmission. The results show the interplay of prion strain and host genotype in governing the molecular, pathological and temporal characteristics of the UK hGH-iCJD epidemic and provide insights into the adaptive mechanisms involved when prions cross genotypic barriers. We conclude that all of the available evidence is consistent with the hypothesis that the UK hGH-iCJD epidemic resulted from transmission of the V2 human prion strain, which is associated with the second most common form of sporadic CJD.

Constraining the magnitude of the largest event in a foreshock-main shock-aftershock sequence

Science.gov (United States)

Shcherbakov, Robert; Zhuang, Jiancang; Ogata, Yosihiko

2018-01-01

Extreme value statistics and Bayesian methods are used to constrain the magnitudes of the largest expected earthquakes in a sequence governed by the parametric time-dependent occurrence rate and frequency-magnitude statistics. The Bayesian predictive distribution for the magnitude of the largest event in a sequence is derived. Two types of sequences are considered, that is, the classical aftershock sequences generated by large main shocks and the aftershocks generated by large foreshocks preceding a main shock. For the former sequences, the early aftershocks during a training time interval are used to constrain the magnitude of the future extreme event during the forecasting time interval. For the latter sequences, the earthquakes preceding the main shock are used to constrain the magnitudes of the subsequent extreme events including the main shock. The analysis is applied retrospectively to past prominent earthquake sequences.

Evolution of the Largest Mammalian Genome.

Science.gov (United States)

Evans, Ben J; Upham, Nathan S; Golding, Goeffrey B; Ojeda, Ricardo A; Ojeda, Agustina A

2017-06-01

The genome of the red vizcacha rat (Rodentia, Octodontidae, Tympanoctomys barrerae) is the largest of all mammals, and about double the size of their close relative, the mountain vizcacha rat Octomys mimax, even though the lineages that gave rise to these species diverged from each other only about 5 Ma. The mechanism for this rapid genome expansion is controversial, and hypothesized to be a consequence of whole genome duplication or accumulation of repetitive elements. To test these alternative but nonexclusive hypotheses, we gathered and evaluated evidence from whole transcriptome and whole genome sequences of T. barrerae and O. mimax. We recovered support for genome expansion due to accumulation of a diverse assemblage of repetitive elements, which represent about one half and one fifth of the genomes of T. barrerae and O. mimax, respectively, but we found no strong signal of whole genome duplication. In both species, repetitive sequences were rare in transcribed regions as compared with the rest of the genome, and mostly had no close match to annotated repetitive sequences from other rodents. These findings raise new questions about the genomic dynamics of these repetitive elements, their connection to widespread chromosomal fissions that occurred in the T. barrerae ancestor, and their fitness effects-including during the evolution of hypersaline dietary tolerance in T. barrerae. ©The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Single-port laparoscopic myomectomy using a new single-port transumbilical morcellation system: initial clinical study.

Science.gov (United States)

Kim, Yong-Wook; Park, Byung-Joon; Ro, Duck-Yeong; Kim, Tae-Eung

2010-01-01

To evaluate the feasibility of single-port laparoscopic myomectomy with transumbilical morcellation and suturing. Continuing prospective study (Canadian Task Force classification II-3). University hospital. Fifteen patients who underwent single-port laparoscopic myomectomy between September 2008 and October 2009 to remove single or multiple uterine myomas, at least 1 in each patient measuring greater than 4 cm in diameter. All single-port laparoscopic myomectomy procedures were performed by a single surgeon (Dr. Y.W. Kim). Myomas were extracted transumbilically by cutting the myomas into smaller pieces with a knife or a conventional electromechanical morcellator. After making a single 1.5- to 2.0-cm umbilical incision, the single-port system, created with a wound retractor and a surgical glove, was inserted. All operations were performed using conventional rigid straight laparoscopic instruments. Laparoscopic suturing was performed in intramural myomas and some subserosal myomas. Patient mean (SD; range) age was 38.3 (5.6; 29-49) years. The number of myomas per patient was 1.6 (1.4; 1-6). The diameter of the largest myomas was 6.1 (1.5; 4.2-9.6) cm. In 4 patients, only a knife was required for transumbilical extraction of myomas, and in 11 patients, transumbilical morcellation with an electromechanical morcellator with or without a knife was used. Transumbilical drainage tubes were inserted into the pelvic cavity in 11 of 15 patients. Operative time was 96.7 (33.8; 35-150) minutes. The decrease in postoperative hemoglobin concentration was 1.8 (1.2; 0.4-3.6) g/dL. During the operations, no patients required blood transfusion. No patients developed postoperative fever. Neither bowel injury nor urinary tract injury occurred in any patient. The postoperative hospital stay was 3.1 (0.8; 2-4) days. Single-port transumbilical morcellation using a conventional electromechanical morcellator with or without a knife is feasible. Single-port laparoscopic myomectomy is an

Africa's largest long-lasting insecticide-treated net producer: lessons from A to Z Textiles.

Science.gov (United States)

Masum, Hassan; Shah, Ronak; Schroeder, Karl; Daar, Abdallah S; Singer, Peter A

2010-12-13

Field trials have demonstrated the efficacy of insecticide-treated nets, and the WHO has recently endorsed a shift toward Long-Lasting Insecticide Treated nets (LLINs) due to factors such as reduced distribution costs. However, the need for LLINs poses several challenges. Is it possible to manufacture LLINs in large quantities in the African continent, where malaria is most endemic? When production is located in low-income countries, what role is played by local funding and employment, scaling up manufacturing, and partnerships? What factors influence availability and pricing? A case study of A to Z Textiles was undertaken to answer the question of how large-scale production of LLINs can occur in a low income setting. One of the largest sources of bed nets for Africa, A to Z Textiles is Africa-based, and its Tanzanian operations have a production capacity of 30 million LLINs per year, along with full WHO recommendation for its nets. Our analysis is based on semi-structured interviews with key informants familiar with A to Z, site visits in Tanzania, and literature reviews.This paper discusses the history and current status of A to Z Textiles, identifies the factors that led to its success, and suggests policy considerations that could support similar initiatives in the future. Local funding, scaling up manufacturing, technology transfer, and partnerships all played important roles in A to Z's ascent, as did perceived benefits of local employment and capacity-building. Regulatory issues and procurement rules acted as barriers. A to Z cost-effectively manufactures high-quality LLINs where malaria is most endemic. With a production capacity of 30 million LLINs per year, and full WHOPES (WHO Pesticide Evaluation Scheme) certification, A to Z Textiles demonstrates how key health goods can be successfully produced in the low-income countries that use them. Its example may be instructive and of high interest to readers in the malaria community, especially in developing

Largest US oil and gas fields, August 1993

Energy Technology Data Exchange (ETDEWEB)

1993-08-06

The Largest US Oil and Gas Fields is a technical report and part of an Energy Information Administration (EIA) series presenting distributions of US crude oil and natural gas resources, developed using field-level data collected by EIA`s annual survey of oil and gas proved reserves. The series` objective is to provide useful information beyond that routinely presented in the EIA annual report on crude oil and natural gas reserves. These special reports also will provide oil and gas resource analysts with a fuller understanding of the nature of US crude oil and natural gas occurrence, both at the macro level and with respect to the specific subjects addressed. The series` approach is to integrate EIA`s crude oil and natural gas survey data with related data obtained from other authoritative sources, and then to present illustrations and analyses of interest to a broad spectrum of energy information users ranging from the general public to oil and gas industry personnel.

Largest US oil and gas fields, August 1993

International Nuclear Information System (INIS)

1993-01-01

The Largest US Oil and Gas Fields is a technical report and part of an Energy Information Administration (EIA) series presenting distributions of US crude oil and natural gas resources, developed using field-level data collected by EIA's annual survey of oil and gas proved reserves. The series' objective is to provide useful information beyond that routinely presented in the EIA annual report on crude oil and natural gas reserves. These special reports also will provide oil and gas resource analysts with a fuller understanding of the nature of US crude oil and natural gas occurrence, both at the macro level and with respect to the specific subjects addressed. The series' approach is to integrate EIA's crude oil and natural gas survey data with related data obtained from other authoritative sources, and then to present illustrations and analyses of interest to a broad spectrum of energy information users ranging from the general public to oil and gas industry personnel

Diatom-inferred hydrological changes and Holocene geomorphic transitioning of Africa's largest estuarine system, Lake St Lucia

Science.gov (United States)

Gomes, M.; Humphries, M. S.; Kirsten, K. L.; Green, A. N.; Finch, J. M.; de Lecea, A. M.

2017-06-01

The diverse lagoons and coastal lakes along the east coast of South Africa occupy incised valleys that were flooded during the rise and subsequent stabilisation of relative sea-level during the Holocene. Sedimentary deposits contained within these waterbodies provide an opportunity to investigate complex hydrological and sedimentological processes, and examine sea-level controls governing system geomorphic evolution. In this paper, we combine diatom and sulfur isotope analyses from two sediment cores extracted from the northern sub-basins of Lake St Lucia, a large shallow estuarine lake that is today largely isolated from direct ocean influence behind a Holocene-Pleistocene barrier complex. Analyses allow the reconstruction of hydrological changes associated with the geomorphic development of the system over the mid-to late Holocene. The sedimentary sequences indicate that St Lucia was a shallow, partially enclosed estuary/embayment dominated by strong tidal flows prior to ∼6200 cal. BP. Infilling was initiated when sea-level rise slowed and stabilised around present day levels, resulting in the accumulation of fine-grained sediment behind an emergent proto-barrier. Diatom assemblages, dominated by marine benthic and epiphytic species, reveal a system structured by marine water influx and characterised by marsh and tidal flat habitats until ∼4550 cal. BP. A shift in the biological community at ∼4550 cal. BP is linked to the development of a back-barrier water body that supported a brackish community. Marine planktonics and enrichments in δ34S suggest recurrent, large-scale barrier inundation events during this time, coincident with a mid-Holocene sea-level highstand. Periodic marine incursions associated with episodes of enhanced storminess and overwash remained prevalent until ∼1200 cal. BP, when further barrier construction ultimately isolated the northern basins from the ocean. This study provides the first reconstruction of the palaeohydrological

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.

Engineered barriers: current status 1989

International Nuclear Information System (INIS)

Atkinson, A.; Marsh, G.B.

1989-06-01

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

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

Photochemical approach to high-barrier films for the encapsulation of flexible laminary electronic devices

Energy Technology Data Exchange (ETDEWEB)

Prager, L., E-mail: lutz.prager@iom-leipzig.de [Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstr. 15, 04318 Leipzig (Germany); Helmstedt, U. [Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstr. 15, 04318 Leipzig (Germany); Herrnberger, H. [Solarion AG, Pereser Höhe 1, Breitscheidstraße 45, 04442 Zwenkau (Germany); Kahle, O. [Fraunhofer-Einrichtung für Polymermaterialien und Composite PYCO, Kantstraße 55, 14513 Teltow (Germany); Kita, F. [AZ Electronic Materials Germany GmbH, Rheingaustraße 190-196, 65203 Wiesbaden (Germany); Münch, M. [Solarion AG, Pereser Höhe 1, Breitscheidstraße 45, 04442 Zwenkau (Germany); Pender, A.; Prager, A.; Gerlach, J.W. [Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstr. 15, 04318 Leipzig (Germany); Stasiak, M. [Fraunhofer-Einrichtung für Polymermaterialien und Composite PYCO, Kantstraße 55, 14513 Teltow (Germany)

2014-11-03

Based on results of preceding research and development, thin gas barriers were made by wet application of perhydropolysilazane solution onto polymer films and its subsequent photo-initiated conversion to dense silica layers applying vacuum ultraviolet irradiation. Compared to the state of the art, these layers were sufficiently improved and characterized by spectroscopic methods, by scanning electron microscopy and by gas permeation measurements. Water vapor transmission rates (WVTR) below 10{sup −2} g m{sup −2} d{sup −1} were achieved. In this way, single barrier films were developed and produced on a pilot plant from roll to roll, 250 mm wide, at speeds up to 10 m min{sup −1}. Two films were laminated using adhesives curable with ultraviolet (UV) light and evaluated by peel tests, gas permeation measurement and climate testing. It could be shown that the described high-barrier laminates which exhibit WVTR ≈ 5 × 10{sup −4} g m{sup −2} d{sup −1}, determined by the calcium mirror method, are suitable for encapsulation of flexible thin-film photovoltaic modules. Durability of the encapsulated modules could be verified in several climate tests including damp-heat, thermo-cycle (heating, freezing, wetting) and UV exposures which are equivalent to more than 20 years of endurance at outdoor conditions in temperate climate. In the frame of further research and technical development it seems to be possible to design a cost efficient industrial scale process for the production of encapsulation films for photovoltaic applications. - Highlights: • Dense silica barrier layers were developed by a photochemical approach. • Polymer based barrier films were laminated yielding flexible high-barrier films. • Using these laminates photovoltaic test modules were encapsulated and tested. • A durability of more than 20 years at outdoor conditions could be proved.

Mediated Intercultural Communication Barrier in No Drama Zone! Group

OpenAIRE

Lizal, Valentino

2015-01-01

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

Evidence-based surgery: knowledge, attitudes, and perceived barriers among surgical trainees.

Science.gov (United States)

Mittal, Rohin; Perakath, Benjamin

2010-01-01

This study was conducted to assess the knowledge and attitude of surgical trainees toward evidence-based medicine (EBM) and their perceived barriers to its practice. The McColl questionnaire and the BARRIERS scale were modified and incorporated into a single questionnaire, which was administered to all surgical trainees attending a Continuing Surgical Education meeting. Department of Surgery, Christian Medical College, Vellore, India. One hundred ten surgical trainees from 22 medical colleges. In all, 84.5% (93/110) trainees returned the questionnaire. The attitudes toward EBM were welcoming, although individual participants reported they welcomed EBM more than their colleagues did. Participants agreed that EBM was useful in everyday practice and that it improved patient care. About 50% of actual practice was considered evidence based. In all, 12.6% (10/89) of participants had received formal training in EBM, and 64.3% (54/84) of participants were aware of the Cochrane database of systemic reviews, but only 35.7% (30/84) read it regularly. Also, 67.8% (61/90) of respondents used protocols and guidelines developed by colleagues. However, 61.5% (56/91) of participants were interested in learning the skills of EBM. The terms absolute risk, relative risk, and clinical effectiveness were understood by >80% of respondents, whereas publication bias, confidence interval, and heterogeneity were poorly understood. The major barriers to practice of EBM were the inability to understand statistical analysis, inadequate facilities for implementation, lack of a single compiled source of literature, relevant literature not being readily available, and insufficient time on the job. Surgical trainees have a positive attitude towards EBM and have some familiarity with the common terms used in EBM. There is a need to increase awareness of, and provide access to, available sources of medical literature. Formal training in EBM, as well as basic statistical analysis, should form a part

Ring distributions leading to species formation: a global topographic analysis of geographic barriers associated with ring species

Directory of Open Access Journals (Sweden)

Monahan William B

2012-03-01

Full Text Available Abstract Background In the mid 20th century, Ernst Mayr and Theodosius Dobzhansky championed the significance of circular overlaps or ring species as the perfect demonstration of speciation, yet in the over 50 years since, only a handful of such taxa are known. We developed a topographic model to evaluate whether the geographic barriers that favor processes leading to ring species are common or rare, and to predict where other candidate ring barriers might be found. Results Of the 952,147 geographic barriers identified on the planet, only about 1% are topographically similar to barriers associated with known ring taxa, with most of the likely candidates occurring in under-studied parts of the world (for example, marine environments, tropical latitudes. Predicted barriers separate into two distinct categories: (i single cohesive barriers (2, associated with taxa that differentiate at smaller spatial scales (salamander: Ensatina eschscholtzii; tree: Acacia karroo; and (ii composite barriers - formed by groups of barriers (each 184,000 to 1.7 million km2 in close geographic proximity (totaling 1.9 to 2.3 million km2 - associated with taxa that differentiate at larger spatial scales (birds: Phylloscopus trochiloides and Larus (sp. argentatus and fuscus. When evaluated globally, we find a large number of cohesive barriers that are topographically similar to those associated with known ring taxa. Yet, compared to cohesive barriers, an order of magnitude fewer composite barriers are similar to those that favor ring divergence in species with higher dispersal. Conclusions While these findings confirm that the topographic conditions that favor evolutionary processes leading to ring speciation are, in fact, rare, they also suggest that many understudied natural systems could provide valuable demonstrations of continuous divergence towards the formation of new species. Distinct advantages of the model are that it (i requires no a priori information on the

Perceived barriers to elective single embryo transfer among IVF professionals: a national survey.

NARCIS (Netherlands)

Peperstraten, A.M. van; Hermens, R.P.M.G.; Nelen, W.L.D.M.; Stalmeier, P.F.M.; Scheffer, G.J.; Grol, R.P.T.M.; Kremer, J.A.M.

2008-01-01

BACKGROUND: After initial years of improvement, the multiple pregnancy rate after in vitro fertilization (IVF) in Europe now remains stable at 23% with single embryo transfer (SET) constituting 19% of all IVF cycles. Although elective SET prevents multiple pregnancies after IVF, couples and

How the largest electric and gas utility companies administer public relations

Energy Technology Data Exchange (ETDEWEB)

Bogart, J.D.

1979-04-12

This article describes the findings of a survey conducted by the author in the second half of 1978 to determine the sizes of the public relations staffs of the nation's largest operating electric and gas utilities, their budgets, organizational differences, and specific functions. Common public relations issues and major public relations problems of the utilities are identified, as well as recent trends or changes in budgeting and organization. Some functional variations of public relations departments among utility companies were detected and described.

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.

The circulating air barrier: Effective prevention of liquid contaminant movement through soil

International Nuclear Information System (INIS)

Gill, R.; Towers, T.; Johnson, H.; Overbey, W.

1995-01-01

The environmental cleanup task facing the United States Department of Energy (DOE) presents enormous technical, planning and institutional challenges, including the need to develop new technologies that are faster, better, safer, and cheaper, in order to expedite site cleanup. Characterization of contaminated sediments resulting from past tank leaks, continued safe operations of the tanks, total confinement of leaking materials, secondary waste minimization, and final closure of the single shell tanks are five of the many facets of the storage tank issue at Hanford and elsewhere in the nation. Each of these issues are considered in the development of the Circulating Air Barrier (CAB). The Circulating Air Barrier system is a desiccant-type barrier designed to prevent the movement of liquid contaminants toward the groundwater by using an air circulation and processing system to lower the water saturation in a targeted subsurface zone below the saturation level required for liquid flow. Vertical or horizontal wells can be installed to create a matrix of air injection and production so that air flows across the target barrier zone to the production wells. In the event of a tank leak, the system serves as a tool for early detection and provides a means to withdraw volatile contaminants to the surface for treatment. Demonstration and full-scale CAB systems have been designed for the Hanford Site. This includes chemical and geological characterization; model development, sensitivity analysis and performance optimization; subsurface configuration and surface processing equipment design; and development of a test program with associated cost estimates

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

OpenAIRE

Olson, James M.

1992-01-01

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

Remarks to the DOE/NARUC conference on natural gas in the post-order 636/EPACT environment

International Nuclear Information System (INIS)

Makowski, J.

1993-01-01

Ways to remove barriers to the efficient use of natural gas are explored. Two summary observations are made. First, natural gas is clearly the fuel of choice among a majority of non-utility generators. Second, virtually every projection shows that power generation is the single largest potential new market for natural gas in North America. Today, suppliers are organizing themselves to serve this market. Methods by which suppliers intend to serve this market are discussed

Cylindrical gate all around Schottky barrier MOSFET with insulated shallow extensions at source/drain for removal of ambipolarity: a novel approach

Science.gov (United States)

Kumar, Manoj; Pratap, Yogesh; Haldar, Subhasis; Gupta, Mridula; Gupta, R. S.

2017-12-01

In this paper TCAD-based simulation of a novel insulated shallow extension (ISE) cylindrical gate all around (CGAA) Schottky barrier (SB) MOSFET has been reported, to eliminate the suicidal ambipolar behavior (bias-dependent OFF state leakage current) of conventional SB-CGAA MOSFET by blocking the metal-induced gap states as well as unwanted charge sharing between source/channel and drain/channel regions. This novel structure offers low barrier height at the source and offers high ON-state current. The I ON/I OFF of ISE-CGAA-SB-MOSFET increases by 1177 times and offers steeper subthreshold slope (~60 mV/decade). However a little reduction in peak cut off frequency is observed and to further improve the cut-off frequency dual metal gate architecture has been employed and a comparative assessment of single metal gate, dual metal gate, single metal gate with ISE, and dual metal gate with ISE has been presented. The improved performance of Schottky barrier CGAA MOSFET by the incorporation of ISE makes it an attractive candidate for CMOS digital circuit design. The numerical simulation is performed using the ATLAS-3D device simulator.

Environmental isotope signatures of the largest freshwater lake in Kerala

International Nuclear Information System (INIS)

Unnikrishnan Warrier, C.

2007-01-01

Sasthamkotta lake, the largest freshwater lake in Kerala, serves as a source for drinking water for more than half a million people. Environmental 137 Cs analysis done on undisturbed sediment core samples reveals that the recent rate of sedimentation is not uniform in the lake. The useful life of lake is estimated as about 800 years. The δD and δ 18 O values of the lake waters indicate that the lake is well mixed with a slight variation horizontally. The stable isotope studies on well waters from the catchment indicate hydraulic communication with the lake and lake groundwater system is flow-through type. Analytical model also supports this view. (author)

ENSO Weather and Coral Bleaching on the Great Barrier Reef, Australia

Science.gov (United States)

McGowan, Hamish; Theobald, Alison

2017-10-01

The most devastating mass coral bleaching has occurred during El Niño events, with bleaching reported to be a direct result of increased sea surface temperatures (SSTs). However, El Niño itself does not cause SSTs to rise in all regions that experience bleaching. Nor is the upper ocean warming trend of 0.11°C per decade since 1971, attributed to global warming, sufficient alone to exceed the thermal tolerance of corals. Here we show that weather patterns during El Niño that result in reduced cloud cover, higher than average air temperatures and higher than average atmospheric pressures, play a crucial role in determining the extent and location of coral bleaching on the world's largest coral reef system, the World Heritage Great Barrier Reef (GBR), Australia. Accordingly, synoptic-scale weather patterns and local atmosphere-ocean feedbacks related to El Niño-Southern Oscillation (ENSO) and not large-scale SST warming due to El Niño alone and/or global warming are often the cause of coral bleaching on the GBR.

CERN: Digital image analysis in the world's largest research center for particle physics

CERN Multimedia

2005-01-01

Those interested in researching into the smallest building blocks that matter is made up of need the largest instruments. CERN, near Geneva, Switzerland is where the most powerful circular accelerator in the world is being built: the Large Hadron Collider (LHC) for proton collisions. It has a circumference of 26.7 km (4 pages)

Electrical characteristics of schottky barriers on 4H-SiC: The effects of barrier height nonuniformity

Science.gov (United States)

Skromme, B. J.; Luckowski, E.; Moore, K.; Bhatnagar, M.; Weitzel, C. E.; Gehoski, T.; Ganser, D.

2000-03-01

Electrical properties, including current-voltage (I-V) and capacitance-voltage (C-V) characteristics, have been measured on a large number of Ti, Ni, and Pt-based Schottky barrier diodes on 4H-SiC epilayers. Various nonideal behaviors are frequently observed, including ideality factors greater than one, anomalously low I-V barrier heights, and excess leakage currents at low forward bias and in reverse bias. The nonidealities are highly nonuniform across individual wafers and from wafer to wafer. We find a pronounced linear correlation between I-V barrier height and ideality factor for each metal, while C-V barrier heights remain constant. Electron beam induced current (EBIC) imaging strongly suggests that the nonidealities result from localized low barrier height patches. These patches are related to discrete crystal defects, which become visible as recombination centers in the EBIC images. Alternative explanations involving generation-recombination current, uniform interfacial layers, and effects related to the periphery are ruled out.

Air barrier systems: Construction applications

Energy Technology Data Exchange (ETDEWEB)

Perrault, J.C

1989-01-01

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

Single top quark production cross section using the ATLAS detector at the LHC

CERN Document Server

Cioara, Irina Antonela; The ATLAS collaboration

2017-01-01

Measurements of single top-quark production in proton-proton collisions are presented based on the 8 TeV and 13 TeV ATLAS datasets. In the leading order process, a W boson is exchanged in the t-channel. The cross-section for the production of single top-quarks and single anti-top-quarks total production cross sections, their ratio, as well as a measurement of the inclusive production cross section is presented. At 8 TeV, differential cross-section measurements of the t-channel process are also reported, these analyses include limits on anomalous contributions to the Wtb vertex and measurement of the top quark polarization. A measurement of the production cross section of a single top quark in association with a W boson, the second largest single-top production mode, is also presented. Finally, evidence for s-channel single-top production in the 8 TeV ATLAS dataset is presented. All measurements are compared to state-of-the-art theoretical calculations.

Effects of topical application of aqueous solutions of hexoses on epidermal permeability barrier recovery rate after barrier disruption.

Science.gov (United States)

Denda, Mitsuhiro

2011-11-01

Previous studies have suggested that hexose molecules influence the stability of phospholipid bilayers. Therefore, the effects of topical application of all 12 stereoisomers of dextro-hexose on the epidermal barrier recovery rate after barrier disruption were evaluated. Immediately after tape stripping, 0.1 m aqueous solution of each hexose was applied on hairless mouse skin. Among the eight dextro-aldohexoses, topical application of altose, idose, mannose and talose accelerated the barrier recovery, while allose, galactose, glucose and gulose had no effect. Among the four dextro-ketohexoses, psicose, fructose, sorbose and tagatose all accelerated the barrier recovery. As the effects of hexoses on the barrier recovery rate appeared within 1 h, the mechanism is unlikely to be genomic. Instead, these hexoses may influence phase transition of the lipid bilayers of lamellar bodies and cell membrane, a crucial step in epidermal permeability barrier homeostasis. © 2011 John Wiley & Sons A/S.

Advanced house air-barrier systems

Energy Technology Data Exchange (ETDEWEB)

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

1996-08-01

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

Large magnetocurrents in double-barrier tunneling transistors

International Nuclear Information System (INIS)

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

2005-01-01

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

Potential barrier classification by short-time measurement

International Nuclear Information System (INIS)

Granot, Er'el; Marchewka, Avi

2006-01-01

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

Potential barrier classification by short-time measurement

Science.gov (United States)

Granot, Er'El; Marchewka, Avi

2006-03-01

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

Enhancement of Hole Confinement by Monolayer Insertion in Asymmetric Quantum-Barrier UVB Light Emitting Diodes

KAUST Repository

Janjua, Bilal

2014-04-01

We study the enhanced hole confinement by having a large bandgap AlGaN monolayer insertion (MLI) between the quantum well (QW) and the quantum barrier (QB). The numerical analysis examines the energy band alignment diagrams, using a self-consistent 6 × 6 k ·p method and, considering carrier distribution, recombination rates (Shockley-Reed-Hall, Auger, and radiative recombination rates), under equilibrium and forward bias conditions. The active region is based on AlaGa1-aN (barrier)/AlbGa1-bN (MLI)/AlcGa1-cN (well)/AldGa1-dN (barrier), where b > d > a > c. A large bandgap AlbGa1-bN mono layer, inserted between the QW and QB, was found to be effective in providing stronger hole confinement. With the proposed band engineering scheme, an increase of more than 30% in spatial overlap of carrier wavefunction was obtained, with a considerable increase in carrier density and direct radiative recombination rates. The single-QW-based UV-LED was designed to emit at 280 nm, which is an effective wavelength for water disinfection.

Penetration through the Skin Barrier

DEFF Research Database (Denmark)

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

2016-01-01

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

Big Data as Information Barrier

Directory of Open Access Journals (Sweden)

Victor Ya. Tsvetkov

2014-07-01

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

Physician variation in perceived barriers to personal health

Directory of Open Access Journals (Sweden)

Rubenfire M

2012-01-01

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

Collaborative spectrum sensing based on the ratio between largest eigenvalue and Geometric mean of eigenvalues

KAUST Repository

Shakir, Muhammad

2011-12-01

In this paper, we introduce a new detector referred to as Geometric mean detector (GEMD) which is based on the ratio of the largest eigenvalue to the Geometric mean of the eigenvalues for collaborative spectrum sensing. The decision threshold has been derived by employing Gaussian approximation approach. In this approach, the two random variables, i.e. The largest eigenvalue and the Geometric mean of the eigenvalues are considered as independent Gaussian random variables such that their cumulative distribution functions (CDFs) are approximated by a univariate Gaussian distribution function for any number of cooperating secondary users and received samples. The approximation approach is based on the calculation of exact analytical moments of the largest eigenvalue and the Geometric mean of the eigenvalues of the received covariance matrix. The decision threshold has been calculated by exploiting the CDF of the ratio of two Gaussian distributed random variables. In this context, we exchange the analytical moments of the two random variables with the moments of the Gaussian distribution function. The performance of the detector is compared with the performance of the energy detector and eigenvalue ratio detector. Analytical and simulation results show that our newly proposed detector yields considerable performance advantage in realistic spectrum sensing scenarios. Moreover, our results based on proposed approximation approach are in perfect agreement with the empirical results. © 2011 IEEE.

Genetic Barrier to Direct Acting Antivirals in HCV Sequences Deposited in the European Databank.

Directory of Open Access Journals (Sweden)

Dimas Alexandre Kliemann

Full Text Available Development of resistance results from mutations in the viral genome, and the presence of selective drug pressure leads to the emergence of a resistant virus population. The aim of this study was to analyze the impact of genetic variability on the genetic barrier to drug resistance to DAAs.The genetic barrier was quantified based on the number and type of nucleotide mutations required to impart resistance, considering full-length HCV NS3, NS5A and NS5B regions segregated by genotype into subtypes 1a, 1b, 2a, 2b and 3a. This study analyzeds 789 NS3 sequences, 708 sequences and 536 NS5B sequences deposited in the European Hepatitis C Virus Database, in the following resistance-associated positions: NS3: F43/I/L/S/V, Q80K/R, R155K/G, A156G/S/T and D168A/C/E/G/H/N/T/V/Y; NS5A: L/M28A/T/V, Q30E/H/R, L31F/I/M/V, H58D or P58S and Y93C/F/H/N/S; NS5B: S282P/R/T, C316H/N/Y, S368T, Y448C/H, S556G/R, D559R.Variants that require only one transversion in NS3 were found in 4 positions and include F43S, R80K, R155K/G and A156T. The genetic barrier to resistance shows subtypic differences at position 155 of the NS3 gene where a single transition is necessary in subtype 1a. In the NS5A gene, 5 positions where only one nucleotide change can confer resistance were found, such as L31M which requires one transversion in all subtypes, except in 0.28% of 1b sequences; and R30H, generated by a single transition, which was found in 10.25% of the sequences of genotype 1b. Other subtypic differences were observed at position 58, where resistance is less likely in genotype 1a because a transversion is required to create the variant 58S. For the NS5B inhibitors, the genetic barrier at positions conferring resistance was nearly identical in subtypes 1a and 1b, and single transitions or transversions were necessary in 5 positions to generate a drug-resistant variant of HCV. The positions C316Y and S556D required only one transition in all genotypes, Y448H and S556 G

Structuring unbreakable hydrophobic barriers in paper

Science.gov (United States)

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

2018-02-01

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

Energy scavenging based on a single-crystal PMN-PT nanobelt

Science.gov (United States)

Wu, Fan; Cai, Wei; Yeh, Yao-Wen; Xu, Shiyou; Yao, Nan

2016-03-01

Self-powered nanodevices scavenging mechanical energy require piezoelectric nanostructures with high piezoelectric coefficients. Here we report the fabrication of a single-crystal (1 - x)Pb(Mg1/3Nb2/3)O3 - xPbTiO3 (PMN-PT) nanobelt with a superior piezoelectric constant (d33 = ~550 pm/V), which is approximately ~150%, 430%, and 2100% of the largest reported values for previous PMN-PT, PZT and ZnO nanostructures, respectively. The high d33 of the single-crystalline PMN-PT nanobelt results from the precise orientation control during its fabrication. As a demonstration of its application in energy scavenging, a piezoelectric nanogenerator (PNG) is built on the single PMN-PT nanobelt, generating a maximum output voltage of ~1.2 V. This value is ~4 times higher than that of a single-CdTe PNG, ~13 times higher than that of a single-ZnSnO3 PNG, and ~26 times higher than that of a single-ZnO PNG. The profoundly increased output voltage of a lateral PNG built on a single PMN-PT nanobelt demonstrates the potential application of PMN-PT nanostructures in energy harvesting, thus enriching the material choices for PNGs.

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

International Nuclear Information System (INIS)

Rabah, K.V.O.

1994-07-01

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

Europe's Babylon: Towards a Single European Language? Esperanto Documents 41A.

Science.gov (United States)

Fettes, Mark

Discussion of the establishment of a single language for Europe's many countries and cultures focuses on the debate over English versus Esperanto as the language of choice. It is argued that the notion that language has not been a major barrier to intellectual exchange is a myth. In addition, while the main European political institutions support…

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.

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

Microstructural evolution of reduced-activation martensitic steel under single and sequential ion irradiations

Energy Technology Data Exchange (ETDEWEB)

Luo, Fengfeng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Guo, Liping, E-mail: guolp@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Jin, Shuoxue; Li, Tiecheng; Zheng, Zhongcheng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Yang, Feng; Xiong, Xuesong; Suo, Jinping [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2013-07-15

Microstructural evolution of super-clean reduced-activation martensitic steels irradiated with single-beam (Fe{sup +}) and sequential-beam (Fe{sup +} plus He{sup +}) at 350 °C and 550 °C was studied. Sequential-beam irradiation induced smaller size and larger number density of precipitates compared to single-beam irradiation at 350 °C. The largest size of cavities was observed after sequential-beam irradiation at 550 °C. The segregation of Cr and W and depletion of Fe in carbides were observed, and the maximum depletion of Fe and enrichment of Cr occurred under irradiation at 350 °C.

Restriction-modification mediated barriers to exogenous DNA uptake and incorporation employed by Prevotella intermedia.

Science.gov (United States)

Johnston, Christopher D; Skeete, Chelsey A; Fomenkov, Alexey; Roberts, Richard J; Rittling, Susan R

2017-01-01

Prevotella intermedia, a major periodontal pathogen, is increasingly implicated in human respiratory tract and cystic fibrosis lung infections. Nevertheless, the specific mechanisms employed by this pathogen remain only partially characterized and poorly understood, largely due to its total lack of genetic accessibility. Here, using Single Molecule, Real-Time (SMRT) genome and methylome sequencing, bisulfite sequencing, in addition to cloning and restriction analysis, we define the specific genetic barriers to exogenous DNA present in two of the most widespread laboratory strains, P. intermedia ATCC 25611 and P. intermedia Strain 17. We identified and characterized multiple restriction-modification (R-M) systems, some of which are considerably divergent between the two strains. We propose that these R-M systems are the root cause of the P. intermedia transformation barrier. Additionally, we note the presence of conserved Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) systems in both strains, which could provide a further barrier to exogenous DNA uptake and incorporation. This work will provide a valuable resource during the development of a genetic system for P. intermedia, which will be required for fundamental investigation of this organism's physiology, metabolism, and pathogenesis in human disease.

Model assessment of protective barrier designs

International Nuclear Information System (INIS)

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

1985-11-01

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

[Blood-brain barrier part III: therapeutic approaches to cross the blood-brain barrier and target the brain].

Science.gov (United States)

Weiss, N; Miller, F; Cazaubon, S; Couraud, P-O

2010-03-01

Over the last few years, the blood-brain barrier has come to be considered as the main limitation for the treatment of neurological diseases caused by inflammatory, tumor or neurodegenerative disorders. In the blood-brain barrier, the close intercellular contact between cerebral endothelial cells due to tight junctions prevents the passive diffusion of hydrophilic components from the bloodstream into the brain. Several specific transport systems (via transporters expressed on cerebral endothelial cells) are implicated in the delivery of nutriments, ions and vitamins to the brain; other transporters expressed on cerebral endothelial cells extrude endogenous substances or xenobiotics, which have crossed the cerebral endothelium, out of the brain and into the bloodstream. Recently, several strategies have been proposed to target the brain, (i) by by-passing the blood-brain barrier by central drug administration, (ii) by increasing permeability of the blood-brain barrier, (iii) by modulating the expression and/or the activity of efflux transporters, (iv) by using the physiological receptor-dependent blood-brain barrier transport, and (v) by creating new viral or chemical vectors to cross the blood-brain barrier. This review focuses on the illustration of these different approaches. Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.

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

Analysis of Multiple Structural Changes in Financial Contagion Based on the Largest Lyapunov Exponents

Directory of Open Access Journals (Sweden)

Rui Wang

2014-01-01

Full Text Available A modified multiple structural changes model is built to test structural breaks of the financial system based on calculating the largest Lyapunov exponents of the financial time series. Afterwards, the Lorenz system is used as a simulation example to inspect the new model. As the Lorenz system has strong nonlinearity, the verification results show that the new model has good capability in both finding the breakpoint and revealing the changes in nonlinear characteristics of the time series. The empirical study based on the model used daily data from the S&P 500 stock index during the global financial crisis from 2005 to 2012. The results provide four breakpoints of the period, which divide the contagion into four stages: stationary, local outbreak, global outbreak, and recovery period. An additional significant result is the obvious chaos characteristic difference in the largest Lyapunov exponents and the standard deviation at various stages, particularly at the local outbreak stage.

Diagnostics of pre-breakdown light emission in a helium coplanar barrier discharge: the presence of neutral bremsstrahlung

Czech Academy of Sciences Publication Activity Database

Navrátil, Z.; Morávek, T.; Ráhel’, J.; Čech, J.; Lalinský, Ondřej; Trunec, D.

2017-01-01

Roč. 26, č. 5 (2017), s. 1-10, č. článku 055025. ISSN 0963-0252 Institutional support: RVO:68081731 Keywords : dielectric barrier discharge * helium * single photon counting * bremsstrahlung * electric field * backward discharge * surface charge Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.302, year: 2016

Emu oil-based lotion effects on neonatal skin barrier during transition from intrauterine to extrauterine life

Directory of Open Access Journals (Sweden)

Zanardo V

2017-08-01

Full Text Available Vincenzo Zanardo,1 David Giarrizzo,2 Francesca Volpe,1 Lara Giliberti,1 Gianluca Straface1 1Division of Perinatal Medicine, Policlinico Abano Terme, Abano Terme, 2CALANTHA Physiology of Lactation Laboratory, Padua, Italy Abstract: Both appropriate hydration and skin surface pH are fundamental in preventing baby skin barrier damage during transition from intrauterine to extrauterine life. However, effects of topical moisturizers on neonatal stratum corneum temperature, pH, hydration, and elasticity have not been scientifically evaluated in vivo. We checked 31 full-term breastfeeding neonates by non-invasive bioengineering method, which is able to evaluate the basal skin barrier (left heel, and assessed at 6±1 hours after birth, and at 1 and 24 hours after emu oil-based topical treatment. The basal skin barrier of right heel (no oil exposure of each newborn was considered as control. We found that a single application of an emu oil-based lotion was effective in improving heel stratum corneum hydration, which increases both skin pH and elasticity without any effect on temperature. Further studies are needed to confirm long-term beneficial effects of this treatment in a very sensitive patient population. Keywords: skin barrier, neonate, emu oil-based lotion, topical treatment

Tribological and wear behavior of yttria stabilized zirconia thermal barrier coatings on mild steel

International Nuclear Information System (INIS)

Farooq, M.; Pervez, A.

2012-01-01

The perfection of the temperature confrontation of the engine essentials can be obtained by claim of a single ceramic thermal barrier coating (TBC) or several composite layers. Engine elements protected by TBC can work safely in elevated temperature range above 1000 degree C. Continuous endeavor to increase thermal resistance of engine the elements requires, apart from laboratory investigations, also numerical study of the different engine parts. The high temperatures and stress concentrations can act as the local sources of damage initiation and defects propagation in the form of cracks. The current study focuses the development of Yttria stabilized zirconia thermal barrier coating by Thermal spray technique. Mild steel was used as a substrate and the coating was then characterized for tribological analysis followed by the optical analysis of wear tracks and found the TBC behavior more promising then steel. (author)

Beating the odds: Successful establishment of a Phase II/III clinical research trial in resource-poor Liberia during the largest-ever Ebola outbreak

Directory of Open Access Journals (Sweden)

J. Doe-Anderson

2016-12-01

Full Text Available It has been argued that a country such as Liberia, not fully recovered from the devastation of decades of civil unrest, lacked the appropriate ethical and regulatory framework, basic human and health care services, and infrastructure to carry out clinical trials according to international standards of quality during a public health emergency. However, as Liberia, Sierra Leone, and Guinea were being ravaged by the largest and most devastating Ebola Virus Disease (EVD outbreak ever recorded, the topic of conducting clinical trials of experimental vaccine and treatment candidates in these resource-poor countries generated the keen interest and concern of scientists, researchers, physicians, bioethicists, philanthropists, and even politicians. Decisive action on behalf of the Liberian government, and a timely positive and supportive response from the United States (U.S. government, led to the formation of PREVAIL (Partnership for Research on Ebola Vaccines in Liberia – a clinical research partnership between the two governments. Within a span of 12 weeks, this partnership accomplished the unimaginable: the successful initiation of a Phase II/III vaccine clinical trial for EVD in Liberia. This paper will discuss the dynamics of the research collaboration, barriers encountered, breakthroughs realized, key elements of success, and lessons learned in the process.

Permeability Barrier Generation in the Martian Lithosphere

Science.gov (United States)

Schools, Joe; Montési, Laurent

2015-11-01

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

World's largest off-road tires to be recycled

Energy Technology Data Exchange (ETDEWEB)

Anon.

2005-07-01

Suncor Energy is the first company in Canada to use a new technology designed uniquely for tire recycling at oil sand facilities. The technology is owned by CuttingEdge Tire Recycling, a partnership between Denesoline Environmental Limited Partnership and Beaver Environmental Rubber Technologies Limited. Suncor has supported the development of this Aboriginal-owned and operated business by offering land, electricity, diesel fuel and stockpiles of used truck tires from its oil sand mining activities. These tires are the largest off-road tires in the world. In this new technology, tires that are worn-out through oil sand mining are shredded in a portable shredder before being recycled for subsequent use by the Alberta Recycling Management Association. 1 fig.

Vertical barriers with increased sorption capacities

International Nuclear Information System (INIS)

Bradl, H.B.

1997-01-01

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

Engineering kinetic barriers in copper metallization

International Nuclear Information System (INIS)

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

2002-01-01

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

A cross-cultural investigation into the dimensional structure and stability of the Barriers to Research and Utilization Scale (BARRIERS Scale).

Science.gov (United States)

Williams, Brett; Brown, Ted; Costello, Shane

2015-10-24

It is important that scales exhibit strong measurement properties including those related to the investigation of issues that impact evidence-based practice. The validity of the Barriers to Research Utilization Scale (BARRIERS Scale) has recently been questioned in a systematic review. This study investigated the dimensional structure and stability of the 28 item BARRIERS Scale when completed by three groups of participants from three different cross-cultural environments. Data from the BARRIERS Scale completed by 696 occupational therapists from Australia (n = 137), Taiwan (n = 413), and the United Kingdom (n = 144) were analysed using principal components analysis, followed by Procrustes Transformation. Poorly fitting items were identified by low communalities, cross-loading, and theoretically inconsistent primary loadings, and were systematically removed until good fit was achieved. The cross-cultural stability of the component structure of the BARRIERS Scale was examined. A four component, 19 item version of the BARRIERS Scale emerged that demonstrated an improved dimensional fit and stability across the three participant groups. The resulting four components were consistent with the BARRIERS Scale as originally conceptualised. Findings from the study suggest that the four component, 19 item version of the BARRIERS Scale is a robust and valid measure for identifying barriers to research utilization for occupational therapists in paediatric health care settings across Australia, United Kingdom, and Taiwan. The four component 19 item version of the BARRIERS Scale exhibited good dimensional structure, internal consistency, and stability.

Barrier experiment: Shock initiation under complex loading

Energy Technology Data Exchange (ETDEWEB)

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

2016-01-12

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

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

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

Science.gov (United States)

Rangarajan, R; Jayaraman, K

2017-01-01

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

Design optimization of single-main-amplifier KrF laser-fusion systems

International Nuclear Information System (INIS)

Harris, D.B.; Pendergrass, J.H.

1985-01-01

KrF lasers appear to be a very promising laser fusion driver for commercial applications. The Large Amplifier Module for the Aurora Laser System at Los Alamos is the largest KrF laser in the world and is currently operating at 5 kJ with 10 to 15 kJ eventually expected. The next generation system is anticipated to be a single-main-amplifier system that generates approximately 100 kJ. This paper examines the cost and efficiency tradeoffs for a complete single-main-amplifier KrF laser fusion experimental facility. It has been found that a 7% efficient $310/joule complete laser-fusion system is possible by using large amplifier modules and high optical fluences

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

Energy barriers in patterned media

NARCIS (Netherlands)

de Vries, Jeroen

2013-01-01

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

Biodentine-a novel dentinal substitute for single visit apexification

Directory of Open Access Journals (Sweden)

Gurudutt Nayak

2014-05-01

Full Text Available Use of an apical plug in management of cases with open apices has gained popularity in recent years. Biodentine, a new calcium silicate-based material has recently been introduced as a dentine substitute, whenever original dentine is damaged. This case report describes single visit apexification in a maxillary central incisor with necrotic pulp and open apex using Biodentine as an apical barrier, and a synthetic collagen material as an internal matrix. Following canal cleaning and shaping, calcium hydroxide was placed as an intracanal medicament for 1 mon. This was followed by placement of small piece of absorbable collagen membrane beyond the root apex to serve as matrix. An apical plug of Biodentine of 5 mm thickness was placed against the matrix using pre-fitted hand pluggers. The remainder of canal was back-filled with thermoplasticized gutta-percha and access cavity was restored with composite resin followed by all-ceramic crown. One year follow-up revealed restored aesthetics and function, absence of clinical signs and symptoms, resolution of periapical rarefaction, and a thin layer of calcific tissue formed apical to the Biodentine barrier. The positive clinical outcome in this case is encouraging for the use of Biodentine as an apical plug in single visit apexification procedures.

SOME OBSERVATIONS ON THE DESIGN OF NOISE BARRIERS

OpenAIRE

Arkadiusz BOCZKOWSKI

2013-01-01

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

Impact of Single-Case Pupil Descriptions on Student Teacher Attitudes towards Inclusive Education

Science.gov (United States)

Röhm, Alexander; Schnöring, Annika; Hastall, Matthias R.

2018-01-01

Institutional and individual stigmatization are still major barriers for children with disabilities to access education. Teacher attitudes towards inclusive education play a crucial role in this regard, and are shaped by single-case descriptions from mass media or other sources. Building on exemplification theory and priming, two experiments with…

Numerical simulation of flood barriers

Science.gov (United States)

Srb, Pavel; Petrů, Michal; Kulhavý, Petr

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