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Sample records for defined tunneling area

  1. Quantum dot resonant tunneling diode single photon detector with aluminum oxide aperture defined tunneling area

    DEFF Research Database (Denmark)

    Li, H.W.; Kardynal, Beata; Ellis, D.J.P.

    2008-01-01

    Quantum dot resonant tunneling diode single photon detector with independently defined absorption and sensing areas is demonstrated. The device, in which the tunneling is constricted to an aperture in an insulating layer in the emitter, shows electrical characteristics typical of high quality res...

  2. Defining the value of injection current and effective electrical contact area for EGaIn-based molecular tunneling junctions.

    Science.gov (United States)

    Simeone, Felice C; Yoon, Hyo Jae; Thuo, Martin M; Barber, Jabulani R; Smith, Barbara; Whitesides, George M

    2013-12-04

    Analysis of rates of tunneling across self-assembled monolayers (SAMs) of n-alkanethiolates SCn (with n = number of carbon atoms) incorporated in junctions having structure Ag(TS)-SAM//Ga2O3/EGaIn leads to a value for the injection tunnel current density J0 (i.e., the current flowing through an ideal junction with n = 0) of 10(3.6±0.3) A·cm(-2) (V = +0.5 V). This estimation of J0 does not involve an extrapolation in length, because it was possible to measure current densities across SAMs over the range of lengths n = 1-18. This value of J0 is estimated under the assumption that values of the geometrical contact area equal the values of the effective electrical contact area. Detailed experimental analysis, however, indicates that the roughness of the Ga2O3 layer, and that of the Ag(TS)-SAM, determine values of the effective electrical contact area that are ~10(-4) the corresponding values of the geometrical contact area. Conversion of the values of geometrical contact area into the corresponding values of effective electrical contact area results in J0(+0.5 V) = 10(7.6±0.8) A·cm(-2), which is compatible with values reported for junctions using top-electrodes of evaporated Au, and graphene, and also comparable with values of J0 estimated from tunneling through single molecules. For these EGaIn-based junctions, the value of the tunneling decay factor β (β = 0.75 ± 0.02 Å(-1); β = 0.92 ± 0.02 nC(-1)) falls within the consensus range across different types of junctions (β = 0.73-0.89 Å(-1); β = 0.9-1.1 nC(-1)). A comparison of the characteristics of conical Ga2O3/EGaIn tips with the characteristics of other top-electrodes suggests that the EGaIn-based electrodes provide a particularly attractive technology for physical-organic studies of charge transport across SAMs.

  3. High Surface Area Tunnels in Hexagonal WO₃.

    Science.gov (United States)

    Sun, Wanmei; Yeung, Michael T; Lech, Andrew T; Lin, Cheng-Wei; Lee, Chain; Li, Tianqi; Duan, Xiangfeng; Zhou, Jun; Kaner, Richard B

    2015-07-08

    High surface area in h-WO3 has been verified from the intracrystalline tunnels. This bottom-up approach differs from conventional templating-type methods. The 3.67 Å diameter tunnels are characterized by low-pressure CO2 adsorption isotherms with nonlocal density functional theory fitting, transmission electron microscopy, and thermal gravimetric analysis. These open and rigid tunnels absorb H(+) and Li(+), but not Na(+) in aqueous electrolytes without inducing a phase transformation, accessing both internal and external active sites. Moreover, these tunnel structures demonstrate high specific pseudocapacitance and good stability in an H2SO4 aqueous electrolyte. Thus, the high surface area created from 3.67 Å diameter tunnels in h-WO3 shows potential applications in electrochemical energy storage, selective ion transfer, and selective gas adsorption.

  4. Ultralarge area MOS tunnel devices for electron emission

    DEFF Research Database (Denmark)

    Thomsen, Lasse Bjørchmar; Nielsen, Gunver; Vendelbo, Søren Bastholm

    2007-01-01

    density. Oxide thicknesses have been extracted by fitting a model based on Fermi-Dirac statistics to the C-V characteristics. By plotting I-V characteristics in a Fowler plot, a measure of the thickness of the oxide can be extracted from the tunnel current. These apparent thicknesses show a high degree......A comparative analysis of metal-oxide-semiconductor (MOS) capacitors by capacitance-voltage (C-V) and current-voltage (I-V) characteristics has been employed to characterize the thickness variations of the oxide on different length scales. Ultralarge area (1 cm(2)) ultrathin (similar to 5 nm oxide......) MOS capacitors have been fabricated to investigate their functionality and the variations in oxide thickness, with the use as future electron emission devices as the goal. I-V characteristics show very low leakage current and excellent agreement to the Fowler-Nordheim expression for the current...

  5. Fabrication and dc characteristics of small-area tantalum and niobium superconducting tunnel junctions

    International Nuclear Information System (INIS)

    Face, D.W.; Prober, D.E.

    1987-01-01

    We discuss the fabrication and dc electrical characteristics of small-area (1--6 μm 2 ) superconducting tunnel junctions with Ta or Nb base electrodes and Pb or Pb/sub 0.9/Bi/sub 0.1/ counterelectrodes. These junctions have very small subgap leakage currents, a ''sharp'' current rise at the sum-gap voltage, and show strong quantum effects when used as microwave mixers. The use of a low-energy (--150 eV) ion cleaning process and a novel step-defined fabrication process that eliminates photoresist processing after base electrode deposition are discussed. Tunnel barriers formed by dc glow discharge oxidation were the most successful. Tunnel barrier formation by thermal oxidation and ion-beam oxidation is also discussed. An oxidized Ta overlayer (--7 nm thick) was found to improve the characteristics of Nb-based junctions. The electrical characteristics of junctions with different electrode and barrier materials are presented and discussed in terms of the physical mechanisms that lead to excess subgap current and to a width of the current rise at the sum-gap voltage

  6. Facility Closure Report for T-Tunnel (U12T), Area 12, Nevada Test Site, Nevada

    International Nuclear Information System (INIS)

    2008-01-01

    This Facility Closure Report (FCR) has been prepared to document the actions taken to permanently close the remaining accessible areas of U12t-Tunnel (T-Tunnel) in Area 12 of the Nevada Test Site (NTS). The closure of T-Tunnel was a prerequisite to transfer facility ownership from the Defense Threat Reduction Agency (DTRA) to the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO). Closure of the facility was accomplished with the cooperation and concurrence of both NNSA/NSO and the Nevada Division of Environmental Protection (NDEP). The purpose of this FCR is to document that the closure of T-Tunnel complied with the closure requirements specified in the Facility Closure Plan for N- and T-Tunnels Area 12, Nevada Test Site (Appendix D) and that the facility is ready for transfer to NNSA/NSO. The Facility Closure Plan (FCP) is provided in Appendix D. T-Tunnel is located approximately 42 miles north of Mercury in Area 12 of the NTS (Figure 1). Between 1970 and 1987, T-Tunnel was used for six Nuclear Weapons Effects Tests (NWETs). The tunnel was excavated horizontally into the volcanic tuffs of Rainier Mesa. The T-Tunnel complex consists of a main access drift with two NWET containment structures, a Gas Seal Plug (GSP), and a Gas Seal Door (GSD) (Figure 2). The T-Tunnel complex was mothballed in 1993 to preserve the tunnel for resumption of testing, should it happen in the future, to stop the discharge of tunnel effluent, and to prevent unauthorized access. This was accomplished by sealing the main drift GSD

  7. Technical basis for removal of 221-T tunnel from airborne radiological area status

    International Nuclear Information System (INIS)

    Geuther, W.J.

    1996-01-01

    This document provides the technical basis for removal of the 221-T Tunnel from airborne radiological control. T Plant Radiological Control has evaluated air sampling data and engineering controls, and determined the necessary administrative controls to make this transition. With these administrative controls (specified within document) in place, the tunnel can be removed from Airborne Radioactive Area status. The removal of the tunnel from airborne status will allow work to be performed within the tunnel under controlled conditions, as outlined in this technical basis, without the use of respiratory protection equipment

  8. INDICATORS FOR DEFINING THE EMITTING AREAS IN TOURISM

    Directory of Open Access Journals (Sweden)

    Dejan Nakovski

    2018-06-01

    Full Text Available Risk estimation or volatility estimation at financial markets, particularly stock exchange markets, is complex Tourism will continue to grow at a faster pace in the future, and it will be one of the leading businesses in the development of global prosperity and welfare but it will be heavily influenced by contemporary trends, such as; demographic trends expressed by the demographic characteristics of the population; economic trends expressed by a decline in poverty and a growth of the middle class; technological revolution and evolution; digitalization of society and tourism; modern and healthy lifestyle; political tensions; security; the threat of terror etc. When we talk about tourism the first signs can be found from the statistic indicators, which show the movement of the tourism markets and the movement of the tourists. Every area of the globe, more or less has a certain attractions that can attract tourist. The authors believe that the most important thing in the development of tourism is how to define the target groups and in which direction to move the tourist offers and destinations so they can be attractive to a certain population. The purpose of this paper will be the analysis of tourist flows in several countries from which we will define the indicators in finding emitting areas in tourism.

  9. 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.

  10. Defining urban and rural areas: a new approach

    Science.gov (United States)

    Arellano, Blanca; Roca, Josep

    2017-10-01

    The separation between the countryside and the city, from rural and urban areas, has been one of the central themes of the literature on urban and territorial studies. The seminal work of Kingsley Davis [10] in the 1950s introduced a wide and fruitful debate which, however, has not yet concluded in a rigorous definition that allows for comparative studies at the national and subnational levels of a scientific nature. In particular, the United Nations (UN) definition of urban and rural population is overly linked to political and administrative factors that make it difficult to use data adequately to understand the human settlement structure of different countries. The present paper seeks to define a more rigorous methodology for the identification of rural and urban areas. For this purpose it uses the night lights supplied by the SNPP satellite, and more specifically by the VIIRS sensor for the determination of the urbanization gradient, and by means of the same construct a more realistic indicator than the statistics provided by the UN. The arrival of electrification to nearly every corner of the planet is certainly the first and most meaningful indicator of artificialization of land. In this sense, this paper proposes a new methodology designed to identify highly impacted (urbanized) landscapes worldwide based on the analysis of satellite imagery of night-time lights. The application of this methodology on a global scale identifies the land highly impacted by light, the urbanization process, and allows an index to be drawn up of Land Impacted by Light per capita (LILpc) as an indicator of the level of urbanization. The methodology used in this paper can be summarized in the following steps: a) a logistic regression between US Urban Areas (UA), as a dependent variable, and night-time light intensity, as an explanatory variable, allows us to establish a nightlight intensity level for the determination of Areas Highly Impacted by Light (AHIL); b) the delimitation of

  11. Mechanism of water inrush in tunnel construction in karst area

    Directory of Open Access Journals (Sweden)

    Liping Li

    2016-05-01

    Full Text Available With the rapid developing trend of long, large and deep construction characteristics for underground engineering in the world, China has the largest number of karst tunnels with the wide scales and great difficulties. As the hydrogeological conditions are becoming unprecedentedly complex, water inrush disaster becomes the bottleneck problem for the further development of traffic tunnels. Based on the statistical analysis of a large number of cases of water inrush in karst tunnels, influence factors of water inrush have been put forward from the view of karst hydrogeological factors and engineering disturbance of human factors. Karst hydrogeological factors include geological defect, strata dip, formation lithology, landform and underground level. Human factors of engineering disturbance include excavation and reinforcement geological prediction, monitoring and measurement of surrounding rock. It also introduces some geological disasters caused by the water inrush in tunnel excavation. In terms of the formation of water inrush channel, water inrush types are divided into geological defects inrush, non-geological defects inrush and the combination. Conclusions will be beneficial to further research on hazards control of underground construction.

  12. The value of MRI iniIdiopathic tarsal tunnel syndrome by measuring the cross-sectional area of tarsal tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Jung; Jeong, Yu Mi; Lee, Sheen Woo; Choi Seung; Kim, Jeong Ho; Park, Hong Gi [Gachon University, Gil Hospital, Incheon (Korea, Republic of)

    2015-03-15

    The purpose of this study was to evaluate the use of MRI as a diagnostic test in tarsal tunnel syndrome. There are no published reports with this aim and no diagnostic standard for idiopathic tarsal tunnel syndrome (TTS) using imaging modalities. We retrospectively searched our Picture Archiving and Communication System data and medical records to identify patients who were clinically and electomyographically diagnosed with idiopathic TTS without space-occupying lesion on MRI. Twenty five patients were included in the patient group. Another twenty-five patients who underwent ankle MRI for Achilles tendon disease were selected and included in the control group. Cross-sectional areas (CSA) of tarsal tunnel were manually measured independently by two radiologists who were blinded to clinical and surgical results, using three-dimensional reconstruction software in our hospital. Measurements were done on axial images at three levels (level 1, tibiotalar joint level; level 2, medial malleolar tip level; level 3, sustentaculum tali level). Patient and control group data were statistically analyzed by the Mann-Whitney test. The mean values of CSA at levels 1, 2, and 3 of the tarsal tunnel were 87.8 mm2, 98.2 mm2, and 105.2 mm2, respectively in the patient group; and 100.0 mm2, 113.8 mm2, and 127.9 mm2 in the control group, respectively, in reader 1; and 86.2 mm2, 97.6 mm2, 105.2 mm2, respectively in the patient group; and 99.7 mm2, 112.3 mm2, 124.4 mm2, respectively, in the control group, in reader 2. The mean CSA in the patient group was significantly less than that of the control group at all three levels (p < 0.05). Intra-class correlation coefficient value between reader 1 and reader 2 were 0.98 in group 1, and 0.97 in group 2, respectively. MRI can be helpful in the assessment of idiopathic tarsal tunnel syndrome. CSA measurements of tarsal tunnel at each level may predict TTS even though there are no space occupying lesions in the tarsal tunnel on MRI.

  13. Hazard connected to railway tunnel construction in karstic area: applied geomorphological and hydrogeological surveys

    Directory of Open Access Journals (Sweden)

    G. Casagrande

    2005-01-01

    Full Text Available In a mature karstic system, the realisation of galleries using the methodology of railway tunnel boring machine (TBM involves particular problems due to the high risk of interference with groundwater (often subject to remarkable level variations and with cavities and/or thick fill deposits. In order to define groundwater features it is necessary to investigate both hydrodynamic and karstification. To define and quantify the karst phenomenon in the epikarst of the Trieste Karst (Italy, an applied geomorphological approach has been experimented with surface and cavity surveys. The surface surveys have contributed to determining the potential karst versus the different outcropping lithologies and to define the structural setting of the rocky mass also through the realisation of geostructural stations and the survey of the main lines thanks to photo-interpretation. Moreover, all the dolines and the cavities present in the area interested by the gallery have been studied by analysing the probable extension of caves and/or of the secondary fill deposits and by evaluating the different genetic models. In an area 900m large and 27km long, which has been studied because of the underground karst, there are 41 dolines having diameters superior to 100m and 93 dolines whose diameters range between 100 and 50m; the dolines whose diameters are inferior to 50m are 282. The entrances of known and registered cavities in the cadastre records are 520. The hypogeal surveys have shown 5 typologies in which it has been possible to group all the cavities present in a hypothetical intersection with the excavation. The comparison between surface and hypogeal structural data and the direction of development of cavities has allowed for the definition of highly karstified discontinuity families, thus having a higher risk. The comparison of the collected data has enabled to identify the lithologies and areas having major risk and thus to quantify the probability of

  14. Hazard connected to railway tunnel construction in karstic area: applied geomorphological and hydrogeological surveys

    Science.gov (United States)

    Casagrande, G.; Cucchi, F.; Zini, L.

    2005-02-01

    In a mature karstic system, the realisation of galleries using the methodology of railway tunnel boring machine (TBM) involves particular problems due to the high risk of interference with groundwater (often subject to remarkable level variations) and with cavities and/or thick fill deposits. In order to define groundwater features it is necessary to investigate both hydrodynamic and karstification. To define and quantify the karst phenomenon in the epikarst of the Trieste Karst (Italy), an applied geomorphological approach has been experimented with surface and cavity surveys. The surface surveys have contributed to determining the potential karst versus the different outcropping lithologies and to define the structural setting of the rocky mass also through the realisation of geostructural stations and the survey of the main lines thanks to photo-interpretation. Moreover, all the dolines and the cavities present in the area interested by the gallery have been studied by analysing the probable extension of caves and/or of the secondary fill deposits and by evaluating the different genetic models. In an area 900m large and 27km long, which has been studied because of the underground karst, there are 41 dolines having diameters superior to 100m and 93 dolines whose diameters range between 100 and 50m; the dolines whose diameters are inferior to 50m are 282. The entrances of known and registered cavities in the cadastre records are 520. The hypogeal surveys have shown 5 typologies in which it has been possible to group all the cavities present in a hypothetical intersection with the excavation. The comparison between surface and hypogeal structural data and the direction of development of cavities has allowed for the definition of highly karstified discontinuity families, thus having a higher risk. The comparison of the collected data has enabled to identify the lithologies and areas having major risk and thus to quantify the probability of intersection with the

  15. Geochemical study of acid mine drainage of the Big Lick Tunnel area, Williamstown, PA

    International Nuclear Information System (INIS)

    Tollin, S.

    1993-01-01

    Acid mine drainage in the anthracite region of Pennsylvania continues to be a significant environmental problem. This study examines the acid mine outflow from the Big Lick Tunnel, north of Williamstown, Dauphin County, Pennsylvania. The tunnel drains abandoned mines on the north side of the Big Lick Mountain. Mining ceased in the area circa 1940, and the tunnel has been in operation since that time. The water, soil and stream bed sediment geochemistry has been studied to determine their changes in chemistry over distance. The pH, TDS and metal concentrations were the primary focus. Metal concentrations were determined using an ICP unit. Data indicates the pH of the outflow to range between 6.7 and 7.3 Fe and Mn concentrations are as high as 9.7 ppb. Extensive metal precipitation (''yellow boy'') occurs within the tunnel and for several hundred meters from the mouth of the tunnel. The combination of near neutral pH and high metal concentration suggest that the drainage is in contact with highly alkaline materials prior to discharge from the tunnel. The geology of the area does not suggest bedrock as the possible source of alkaline material. One hypothesis is that the acidic water is reacting with the concrete tunnel and being neutralized. Data also suggests that the Fe precipitates much quicker than the Mn, resulting in a zonation between Fe-rich and Mn-rich sediments along the length of the drainage

  16. Dose calculations for the concrete water tunnels at 190-C Area, Hanford Site

    International Nuclear Information System (INIS)

    Kamboj, S.; Yu, C.

    1997-01-01

    The RESRAD-BUILD code was used to calculate the radiological dose from the contaminated concrete water tunnels at the 190-C Area at the Hanford Site. Two exposure scenarios, recreationist and maintenance worker, were considered. A residential scenario was not considered because the material was assumed to be left intact (i.e., the concrete would not be rubbleized because the location would not be suitable for construction of a house). The recreationist was assumed to use the tunnel for 8 hours per day for 1 week as an overnight shelter. The maintenance worker was assumed to spend 20 hours per year working in the tunnel. Six exposure pathways were considered in calculating the dose. Three external exposure pathways involved penetrating radiation emitted directly from the contaminated tunnel floor, emitted from radioactive particulates deposited on the tunnel floor, and resulting from submersion in airborne radioactive particulates. Three internal exposure pathways involved inhalation of airborne radioactive particulates; inadvertent direct ingestion of removable, contaminated material on the tunnel floor; and inadvertent indirect ingestion of airborne particulates deposited on the tunnel floor. The gradual removal of surface contamination over time and the ingrowth of decay products were considered in calculating the dose at different times. The maximum doses were estimated to be 1.5 mrem/yr for the recreationist and 0.34 mrem/yr for the maintenance worker

  17. A model to relate wind tunnel measurements to open field odorant emissions from liquid area sources

    Science.gov (United States)

    Lucernoni, F.; Capelli, L.; Busini, V.; Sironi, S.

    2017-05-01

    Waste Water Treatment Plants are known to have significant emissions of several pollutants and odorants causing nuisance to the near-living population. One of the purposes of the present work is to study a suitable model to evaluate odour emissions from liquid passive area sources. First, the models describing volatilization under a forced convection regime inside a wind tunnel device, which is the sampling device that typically used for sampling on liquid area sources, were investigated. In order to relate the fluid dynamic conditions inside the hood to the open field and inside the hood a thorough study of the models capable of describing the volatilization phenomena of the odorous compounds from liquid pools was performed and several different models were evaluated for the open field emission. By means of experimental tests involving pure liquid acetone and pure liquid butanone, it was verified that the model more suitable to describe precisely the volatilization inside the sampling hood is the model for the emission from a single flat plate in forced convection and laminar regime, with a fluid dynamic boundary layer fully developed and a mass transfer boundary layer not fully developed. The proportionality coefficient for the model was re-evaluated in order to account for the specific characteristics of the adopted wind tunnel device, and then the model was related with the selected model for the open field thereby computing the wind speed at 10 m that would cause the same emission that is estimated from the wind tunnel measurement furthermore, the field of application of the proposed model was clearly defined for the considered models during the project, discussing the two different kinds of compounds commonly found in emissive liquid pools or liquid spills, i.e. gas phase controlled and liquid phase controlled compounds. Lastly, a discussion is presented comparing the presented approach for emission rates recalculation in the field, with other approaches

  18. Fully low voltage and large area searching scanning tunneling microscope

    International Nuclear Information System (INIS)

    Pang, Zongqiang; Wang, Jihui; Lu, Qingyou

    2009-01-01

    We present a novel scanning tunneling microscope (STM), which allows the tip to travel a large distance (millimeters) on the sample and take images (to find microscopic targets) anywhere it reaches without losing atomic resolution. This broad range searching capability, together with the coarse approach and scan motion, is all done with only one single piezoelectric tube scanner as well as with only low voltages (<15 V). Simple structure, low interference and high precision are thus achieved. To this end, a pillar and a tube scanner are mounted in parallel on a base with one ball glued on the pillar top and two balls glued on the scanner top. These three balls form a narrow triangle, which supports a triangular slider piece. By inertial stepping, the scanner can move the slider toward the pillar (coarse approach) or rotate the slider about the pillar (travel along sample surface). Since all the stepping motions are driven by the scanner's lateral bending which is large per unit voltage, high voltages are unnecessary. The technology is also applicable to scanning force microscopes (SFM) such as atomic force microscopes (AFM), etc

  19. Security Analysis of a Software Defined Wide Area Network Solution

    OpenAIRE

    Rajendran, Ashok

    2016-01-01

    Enterprise wide area network (WAN) is a private network that connects the computers and other devices across an organisation's branch locations and the data centers. It forms the backbone of enterprise communication. Currently, multiprotocol label switching (MPLS) is commonly used to provide this service. As a recent alternative to MPLS, software-dened wide area networking (SD-WAN) solutions are being introduced as an IP based cloud-networking service for enterprises. SD-WAN virtualizes the n...

  20. Graphene-Molybdenum Disulfide-Graphene Tunneling Junctions with Large-Area Synthesized Materials.

    Science.gov (United States)

    Joiner, Corey A; Campbell, Philip M; Tarasov, Alexey A; Beatty, Brian R; Perini, Chris J; Tsai, Meng-Yen; Ready, William J; Vogel, Eric M

    2016-04-06

    Tunneling devices based on vertical heterostructures of graphene and other 2D materials can overcome the low on-off ratios typically observed in planar graphene field-effect transistors. This study addresses the impact of processing conditions on two-dimensional materials in a fully integrated heterostructure device fabrication process. In this paper, graphene-molybdenum disulfide-graphene tunneling heterostructures were fabricated using only large-area synthesized materials, unlike previous studies that used small exfoliated flakes. The MoS2 tunneling barrier is either synthesized on a sacrificial substrate and transferred to the bottom-layer graphene or synthesized directly on CVD graphene. The presence of graphene was shown to have no impact on the quality of the grown MoS2. The thickness uniformity of MoS2 grown on graphene and SiO2 was found to be 1.8 ± 0.22 nm. XPS and Raman spectroscopy are used to show how the MoS2 synthesis process introduces defects into the graphene structure by incorporating sulfur into the graphene. The incorporation of sulfur was shown to be greatly reduced in the absence of molybdenum suggesting molybdenum acts as a catalyst for sulfur incorporation. Tunneling simulations based on the Bardeen transfer Hamiltonian were performed and compared to the experimental tunneling results. The simulations show the use of MoS2 as a tunneling barrier suppresses contributions to the tunneling current from the conduction band. This is a result of the observed reduction of electron conduction within the graphene sheets.

  1. Median nerve cross-sectional area and MRI diffusion characteristics: normative values at the carpal tunnel

    International Nuclear Information System (INIS)

    Yao, Lawrence; Gai, Neville

    2009-01-01

    Enlargement of the median nerve is an objective potential imaging sign of carpal tunnel syndrome. Diffusion tensor MRI (DTI) may provide additional structural information that may prove useful in characterizing median neuropathy. This study further examines normal values for median nerve cross-sectional area (CSA), apparent diffusion coefficient (ADC), and fractional anisotropy (FA). Twenty-three wrists in 17 healthy volunteers underwent MRI of the wrist at 3 T. In 13 subjects, DTI was performed at a B value of 600 mm 2 /s. Median nerve CSA, ADC, and FA were analyzed at standardized anatomic levels. Mean (SD) median nerve CSA within the proximal carpal tunnel was 10.0 (3.4) mm 2 . The mean (SD) FA of the median nerve was 0.71 (0.06) and 0.70 (0.13) proximal to and within the carpal tunnel, respectively. There was a significant difference between nerve CSA and ADC, but not FA, at the distal forearm and proximal carpal tunnel. Nerve CSA, ADC, and FA did not differ between men and women or between dominant and non-dominant wrists. Nerve CSA at the proximal carpal tunnel was positively correlated with subject age and body mass index. Our results suggest a 90% upper confidence limit for normal median nerve CSA of 14.4 mm 2 at the proximal carpal tunnel, higher than normal limits reported by many ultrasound studies. We observed a difference between the CSA and ADC, but not the FA, of the median nerve at the distal forearm and proximal carpal tunnel levels. (orig.)

  2. Experimental Study on RFID Antenna Reading Areas in a Tunnel System

    Directory of Open Access Journals (Sweden)

    Kai Kordelin

    2017-01-01

    Full Text Available We study optimized antenna reading area mappings for a radiofrequency identification- (RFID- based access monitoring system, used in an underground nuclear waste storage facility. We shortly introduce the access monitoring system developed for the ONKALO tunnel in Finland and describe the antenna mounting points as well as the research area. Finally, we study the measurement results of the antenna reading areas and factors that affect the reading area size. Based on our results, in addition to antenna location and direction, absorption to obstacles, reflections, diffraction, scattering, and refraction affect the antenna reading area.

  3. Contact area between femoral tunnel and interference screw in anatomic rectangular tunnel ACL reconstruction: a comparison of outside-in and trans-portal inside-out techniques.

    Science.gov (United States)

    Hiramatsu, Kunihiko; Mae, Tatsuo; Tachibana, Yuta; Nakagawa, Shigeto; Shino, Konsei

    2018-02-01

    The purpose of this study was to compare the femoral tunnel length, the femoral graft bending angle at the femoral tunnel aperture, and the contact area between the femoral tunnel wall and an interference screw used for fixation in anatomic rectangular tunnel anterior cruciate ligament (ACL) reconstruction (ART ACLR). The study included 149 patients with primary ACL injury who underwent ART ACLR. Preoperatively, flexion angle of the index knee was checked under general anaesthesia. Those of less than 130° of passive flexion were assigned to the outside-in (OI) technique (78 patients), while the others to the trans-portal inside-out (TP) technique (71 patients). The patients underwent computed tomography with multiplanar reconstruction at 3-5 weeks post-operatively. Femoral tunnel length, graft bending angle, and contact ratio between the IFS and femoral tunnel were assessed. P contact ratio in the OI technique was significantly larger than that in the TP technique at every point in the femoral tunnel (P contact ratio than the TP technique after ART ACLR. Retrospective comparative study, Level III.

  4. Analysis on ventilation pressure of fire area in longitudinal ventilation of underground tunnel

    Science.gov (United States)

    Li, Jiaxin; Li, Yanfeng; Feng, Xiao; Li, Junmei

    2018-03-01

    In order to solve the problem of ventilation pressure loss in the fire area under the fire condition, the wind pressure loss model of the fire area is established based on the thermodynamic equilibrium relation. The semi-empirical calculation formula is obtained by using the model experiment and CFD simulation. The validity of the formula is verified. The results show that the ventilation pressure loss in the fire zone is proportional to the convective heat release rate at the critical velocity, which is inversely proportional to the upstream ventilation velocity and the tunnel cross-sectional area. The proposed formula is consistent with the law of the tunnel fire test fitting formula that results are close, in contrast, the advantage lies in a clear theoretical basis and ventilation velocity values. The resistance of road tunnel ventilation system is calculated accurately and reliably, and then an effective emergency ventilation operation program is developed. It is necessary to consider the fire zone ventilation pressure loss. The proposed ventilation pressure loss formula can be used for design calculation after thorough verification.

  5. Preliminary design of CERN Future Circular Collider tunnel: first evaluation of the radiation environment in critical areas for electronics

    Science.gov (United States)

    Infantino, Angelo; Alía, Rubén García; Besana, Maria Ilaria; Brugger, Markus; Cerutti, Francesco

    2017-09-01

    As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, called Future Circular Collider (FCC-hh), running at center-of-mass energies of up to 100 TeV in a new 100 km tunnel. The study includes a 90-350 GeV lepton collider (FCC-ee) as well as a lepton-hadron option (FCC-he). In this work, FLUKA Monte Carlo simulation was extensively used to perform a first evaluation of the radiation environment in critical areas for electronics in the FCC-hh tunnel. The model of the tunnel was created based on the original civil engineering studies already performed and further integrated in the existing FLUKA models of the beam line. The radiation levels in critical areas, such as the racks for electronics and cables, power converters, service areas, local tunnel extensions was evaluated.

  6. Preliminary design of CERN Future Circular Collider tunnel: first evaluation of the radiation environment in critical areas for electronics

    Directory of Open Access Journals (Sweden)

    Infantino Angelo

    2017-01-01

    Full Text Available As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, called Future Circular Collider (FCC-hh, running at center-of-mass energies of up to 100 TeV in a new 100 km tunnel. The study includes a 90-350 GeV lepton collider (FCC-ee as well as a lepton-hadron option (FCC-he. In this work, FLUKA Monte Carlo simulation was extensively used to perform a first evaluation of the radiation environment in critical areas for electronics in the FCC-hh tunnel. The model of the tunnel was created based on the original civil engineering studies already performed and further integrated in the existing FLUKA models of the beam line. The radiation levels in critical areas, such as the racks for electronics and cables, power converters, service areas, local tunnel extensions was evaluated.

  7. Pollutant Plume Dispersion over Hypothetical Urban Areas based on Wind Tunnel Measurements

    Science.gov (United States)

    Mo, Ziwei; Liu, Chun-Ho

    2017-04-01

    Gaussian plume model is commonly adopted for pollutant concentration prediction in the atmospheric boundary layer (ABL). However, it has a number of limitations being applied to pollutant dispersion over complex land-surface morphology. In this study, the friction factor (f), as a measure of aerodynamic resistance induced by rough surfaces in the engineering community, was proposed to parameterize the vertical dispersion coefficient (σz) in the Gaussian model. A series of wind tunnel experiments were carried out to verify the mathematical hypothesis and to characterize plume dispersion as a function of surface roughness as well. Hypothetical urban areas, which were assembled in the form of idealized street canyons of different aspect (building-height-to-street-width) ratios (AR = 1/2, 1/4, 1/8 and 1/12), were fabricated by aligning identical square aluminum bars at different separation apart in cross flows. Pollutant emitted from a ground-level line source into the turbulent boundary layer (TBL) was simulated using water vapour generated by ultrasonic atomizer. The humidity and the velocity (mean and fluctuating components) were measured, respectively, by humidity sensors and hot-wire anemometry (HWA) with X-wire probes in streamwise and vertical directions. Wind tunnel results showed that the pollutant concentration exhibits the conventional Gaussian distribution, suggesting the feasibility of using water vapour as a passive scalar in wind tunnel experiments. The friction factor increased with decreasing aspect ratios (widening the building separation). It was peaked at AR = 1/8 and decreased thereafter. Besides, a positive correlation between σz/xn (x is the distance from the pollutant source) and f1/4 (correlation coefficient r2 = 0.61) was observed, formulating the basic parameterization of plume dispersion over urban areas.

  8. Vehicle autonomous localization in local area of coal mine tunnel based on vision sensors and ultrasonic sensors.

    Directory of Open Access Journals (Sweden)

    Zirui Xu

    Full Text Available This paper presents a vehicle autonomous localization method in local area of coal mine tunnel based on vision sensors and ultrasonic sensors. Barcode tags are deployed in pairs on both sides of the tunnel walls at certain intervals as artificial landmarks. The barcode coding is designed based on UPC-A code. The global coordinates of the upper left inner corner point of the feature frame of each barcode tag deployed in the tunnel are uniquely represented by the barcode. Two on-board vision sensors are used to recognize each pair of barcode tags on both sides of the tunnel walls. The distance between the upper left inner corner point of the feature frame of each barcode tag and the vehicle center point can be determined by using a visual distance projection model. The on-board ultrasonic sensors are used to measure the distance from the vehicle center point to the left side of the tunnel walls. Once the spatial geometric relationship between the barcode tags and the vehicle center point is established, the 3D coordinates of the vehicle center point in the tunnel's global coordinate system can be calculated. Experiments on a straight corridor and an underground tunnel have shown that the proposed vehicle autonomous localization method is not only able to quickly recognize the barcode tags affixed to the tunnel walls, but also has relatively small average localization errors in the vehicle center point's plane and vertical coordinates to meet autonomous unmanned vehicle positioning requirements in local area of coal mine tunnel.

  9. Vehicle autonomous localization in local area of coal mine tunnel based on vision sensors and ultrasonic sensors.

    Science.gov (United States)

    Xu, Zirui; Yang, Wei; You, Kaiming; Li, Wei; Kim, Young-Il

    2017-01-01

    This paper presents a vehicle autonomous localization method in local area of coal mine tunnel based on vision sensors and ultrasonic sensors. Barcode tags are deployed in pairs on both sides of the tunnel walls at certain intervals as artificial landmarks. The barcode coding is designed based on UPC-A code. The global coordinates of the upper left inner corner point of the feature frame of each barcode tag deployed in the tunnel are uniquely represented by the barcode. Two on-board vision sensors are used to recognize each pair of barcode tags on both sides of the tunnel walls. The distance between the upper left inner corner point of the feature frame of each barcode tag and the vehicle center point can be determined by using a visual distance projection model. The on-board ultrasonic sensors are used to measure the distance from the vehicle center point to the left side of the tunnel walls. Once the spatial geometric relationship between the barcode tags and the vehicle center point is established, the 3D coordinates of the vehicle center point in the tunnel's global coordinate system can be calculated. Experiments on a straight corridor and an underground tunnel have shown that the proposed vehicle autonomous localization method is not only able to quickly recognize the barcode tags affixed to the tunnel walls, but also has relatively small average localization errors in the vehicle center point's plane and vertical coordinates to meet autonomous unmanned vehicle positioning requirements in local area of coal mine tunnel.

  10. Fabrication of nanometer flat areas onto YBa2Cu3O7-x thin film surfaces by scanning tunneling microscope

    International Nuclear Information System (INIS)

    Virtanen, J.A.; Suketu, P.; Huth, G.C.; Cho, Z.H.

    1991-01-01

    A scanning tunneling microscope was used to mechanically ''mill'' nanometer flat areas of up to 1600 μm 2 on high temperature superconducting (HTS) films of YBa 2 Cu 3 O 7-x which were originally formed by laser ablation. Flatness to a standard deviation of 2 nm in height was found to be characteristic of milled areas. It was subsequently possible to mill trenches and ditches onto these flat areas. Scanning tunneling measurements of the exposed layered structure of the milled HTS surface are also reported. Surface modifications are also possible by the application of voltage pulse to the tunneling tip. The combination of electrical pulses and milling offer a possibility of mixed electromechanical patterning of the film

  11. Defining Primary Care Shortage Areas: Do GIS-based Measures Yield Different Results?

    Science.gov (United States)

    Daly, Michael R; Mellor, Jennifer M; Millones, Marco

    2018-02-12

    To examine whether geographic information systems (GIS)-based physician-to-population ratios (PPRs) yield determinations of geographic primary care shortage areas that differ from those based on bounded-area PPRs like those used in the Health Professional Shortage Area (HPSA) designation process. We used geocoded data on primary care physician (PCP) locations and census block population counts from 1 US state to construct 2 shortage area indicators. The first is a bounded-area shortage indicator defined without GIS methods; the second is a GIS-based measure that measures the populations' spatial proximity to PCP locations. We examined agreement and disagreement between bounded shortage areas and GIS-based shortage areas. Bounded shortage area indicators and GIS-based shortage area indicators agree for the census blocks where the vast majority of our study populations reside. Specifically, 95% and 98% of the populations in our full and urban samples, respectively, reside in census blocks where the 2 indicators agree. Although agreement is generally high in rural areas (ie, 87% of the rural population reside in census blocks where the 2 indicators agree), agreement is significantly lower compared to urban areas. One source of disagreement suggests that bounded-area measures may "overlook" some shortages in rural areas; however, other aspects of the HPSA designation process likely mitigate this concern. Another source of disagreement arises from the border-crossing problem, and it is more prevalent. The GIS-based PPRs we employed would yield shortage area determinations that are similar to those based on bounded-area PPRs defined for Primary Care Service Areas. Disagreement rates were lower than previous studies have found. © 2018 National Rural Health Association.

  12. The tunneling magnetoresistance current dependence on cross sectional area, angle and temperature

    Directory of Open Access Journals (Sweden)

    Z. H. Zhang

    2015-03-01

    Full Text Available The magnetoresistance of a MgO-based magnetic tunnel junction (MTJ was studied experimentally. The magnetoresistance as a function of current was measured systematically on MTJs for various MgO cross sectional areas and at various temperatures from 7.5 to 290.1 K. The resistance current dependence of the MTJ was also measured for different angles between the two ferromagnetic layers. By considering particle and angular momentum conservation of transport electrons, the current dependence of magnetoresistance can be explained by the changing of spin polarization in the free magnetic layer of the MTJ. The changing of spin polarization is related to the magnetoresistance, its angular dependence and the threshold current where TMR ratio equals zero. A phenomenological model is used which avoid the complicated barrier details and also describes the data.

  13. Mitigation of landslide area around railway tunnel, South Sumatra Province, Indonesia

    Science.gov (United States)

    Toha, M. Taufik; Setiabudidaya, Dedi; Komar, Syamsul; Bochori, Ghadafi, Moamar A.; Adiwarman, Mirza; Rahim, S. E.

    2017-09-01

    Adequate and safe railway line infrastructures as well as facilities are required to support the rail transport system in South Sumatra. The slope stability along railway line of Lahat-Lubuk Linggau South Sumatra were studied during landslide that occured on January 23th, 2016. The landslide occurred on the mouth of railway tunnel in Gunung Gajah Village, Lahat District that causing the railway transportation system had to be stopped for a few days. A comprehensive research was conducted to analyze the causes of the landslide and to identify other landslide risky areas along the railway line Lahat-Lubuk Linggau. The research activities included surveying, sampling, laboratory testing, investigating condition of geology, geotechnics, hydrogeology/hydrology, morphology and land use. The factors that cause landslide in the past studies were found to be morphology, structural geology, physical and mechanical characteristics, hydrogeology, hydrology, external forces (train vibration, earthquake). Results back analysis of slope stability when the landslide occurred showed that the value Safety Factor (SF) = 1, angle of friction = 0°, and cohesion = 0.49 kg/cm2 (49 kPa). Based on the observation and analysis of the condition of the morphology and orientation of the structure of the rock layers, there was a location prone to landslide (labile) in the surrounding area of the landslide. Mitigations to potential landslide in adjacent area were building a retaining wall, draining channels, and shortcrete at the rock wall after landslides and maintaining the land use around the slopes.

  14. Rates of First Episode of Psychosis in a Defined Catchment Area in Greece

    OpenAIRE

    Peritogiannis, Vaios; Mantas, Christos; Tatsioni, Athina; Mavreas, Venetsanos

    2013-01-01

    This is the first Greek study presenting epidemiologic data on first-episode psychosis (FEP) patients in a defined catchment area. Data for first episode psychotic patients during a two-year period (2008 and 2009) were obtained by all the mental health providers in the area, public or private. A total of 132 FEP patients were examined in the 2-year period in the catchment area. Most of the patients (61.4%) were diagnosed and treated by private practicing psychiatrists. Statistical analysis sh...

  15. Diagnostic strategies using physical examination are minimally useful in defining carpal tunnel syndrome in population-based research studies.

    Science.gov (United States)

    Descatha, A; Dale, A-M; Franzblau, A; Coomes, J; Evanoff, B

    2010-02-01

    We evaluated the utility of physical examination manoeuvres in the prediction of carpal tunnel syndrome (CTS) in a population-based research study. We studied a cohort of 1108 newly employed workers in several industries. Each worker completed a symptom questionnaire, a structured physical examination and nerve conduction study. For each hand, our CTS case definition required both median nerve conduction abnormality and symptoms classified as "classic" or "probable" on a hand diagram. We calculated the positive predictive values and likelihood ratios for physical examination manoeuvres in subjects with and without symptoms. The prevalence of CTS in our cohort was 1.2% for the right hand and 1.0% for the left hand. The likelihood ratios of a positive test for physical provocative tests ranged from 2.0 to 3.3, and those of a negative test from 0.3 to 0.9. The post-test probability of positive testing was study found that physical examination, alone or in combination with symptoms, was not predictive of CTS in a working population. We suggest using specific symptoms as a first-level screening tool, and nerve conduction study as a confirmatory test, as a case definition strategy in research settings.

  16. Facility Closure Report for Tunnel U16a, Area 16, Nevada Test Site, Nevada

    International Nuclear Information System (INIS)

    2009-01-01

    U16a is not listed in the Federal Facility Agreement and Consent Order. The closure of U16a was sponsored by the Defense Threat Reduction Agency (DTRA) and performed with the cooperation of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the Nevada Division of Environmental Protection. This report documents closure of this site as identified in the DTRA Fiscal Year 2008 Statement of Work, Task 6.3. Closure activities included: (1) Removing and disposing of a shack and its contents; (2) Disposing of debris from within the shack and in the vicinity of the tunnel entrance; (3) Verifying that the tunnel is empty; (4) Welding screened covers over tunnel vent holes to limit access and allow ventilation; and (5) Constructing a full-tunnel cross-section fibercrete bulkhead to prevent access to the tunnel Field activities were conducted from July to August 2008.

  17. Parametric Method to Define Area of Allowable Configurations while Changing Position of Restricted Zones

    Science.gov (United States)

    Pritykin, F. N.; Nefedov, D. I.; Rogoza, Yu A.; Zinchenko, Yu V.

    2018-03-01

    The article presents the findings related to the development of the module for automatic collision detection of the manipulator with restricted zones for virtual motion modeling. It proposes the parametric method for specifying the area of allowable joint configurations. The authors study the cases when restricted zones are specified using the horizontal plane or front-projection planes. The joint coordinate space is specified by rectangular axes in the direction of which the angles defining the displacements in turning pairs are laid off. The authors present the results of modeling which enabled to develop a parametric method for specifying a set of cross-sections defining the shape and position of allowable configurations in different positions of a restricted zone. All joint points that define allowable configurations refer to the indicated sections. The area of allowable configurations is specified analytically by using several kinematic surfaces that limit it. A geometric analysis is developed based on the use of the area of allowable configurations characterizing the position of the manipulator and reported restricted zones. The paper presents numerical calculations related to virtual simulation of the manipulator path performed by the mobile robot Varan when using the developed algorithm and restricted zones. The obtained analytical dependencies allow us to define the area of allowable configurations, which is a knowledge pool to ensure the intelligent control of the manipulator path in a predefined environment. The use of the obtained region to synthesize a joint trajectory makes it possible to correct the manipulator path to foresee and eliminate deadlocks when synthesizing motions along the velocity vector.

  18. AREA EFFICIENT FRACTIONAL SAMPLE RATE CONVERSION ARCHITECTURE FOR SOFTWARE DEFINED RADIOS

    Directory of Open Access Journals (Sweden)

    Latha Sahukar

    2014-09-01

    Full Text Available The modern software defined radios (SDRs use complex signal processing algorithms to realize efficient wireless communication schemes. Several such algorithms require a specific symbol to sample ratio to be maintained. In this context the fractional rate converter (FRC becomes a crucial block in the receiver part of SDR. The paper presents an area optimized dynamic FRC block, for low power SDR applications. The limitations of conventional cascaded interpolator and decimator architecture for FRC are also presented. Extending the SINC function interpolation based architecture; towards high area optimization and providing run time configuration with time register are presented. The area and speed analysis are carried with Xilinx FPGA synthesis tools. Only 15% area occupancy with maximum clock speed of 133 MHz are reported on Spartan-6 Lx45 Field Programmable Gate Array (FPGA.

  19. A criterion for flatness in minimal area metrics that define string diagrams

    International Nuclear Information System (INIS)

    Ranganathan, K.; Massachusetts Inst. of Tech., Cambridge, MA

    1992-01-01

    It has been proposed that the string diagrams of closed string field theory be defined by a minimal area problem that requires that all nontrivial homotopy curves have length greater than or equal to 2π. Consistency requires that the minimal area metric be flat in a neighbourhood of the punctures. The theorem proven in this paper, yields a criterion which if satisfied, will ensure this requirement. The theorem states roughly that the metric is flat in an open set, U if there is a unique closed curve of length 2π through every point in U and all of these closed curves are in the same free homotopy class. (orig.)

  20. Demonstrating the utility of boron based precursor molecules for selective area deposition in a scanning tunneling microscope

    International Nuclear Information System (INIS)

    Perkins, F.K.; Onellion, M.; Lee, S.; Bowben, T.A.

    1992-01-01

    The scanning tunneling microscope (STM) can be used to selectively deposit material from a gaseous precursor compound. Ultrasmall (less than a 100 nm across) spatial dimensions for selective area deposition may be achieved by this means. In this paper the authors outline a scheme foreselecting and designing main group cluster compounds and organometallics for this type of selective area deposition using nido-decaborane(14) as an example

  1. Road and Railroad Tunnels

    Data.gov (United States)

    Department of Homeland Security — Tunnels in the United States According to the HSIP Tiger Team Report, a tunnel is defined as a linear underground passageway open at both ends. This dataset is based...

  2. Rates of first episode of psychosis in a defined catchment area in Greece.

    Science.gov (United States)

    Peritogiannis, Vaios; Mantas, Christos; Tatsioni, Athina; Mavreas, Venetsanos

    2013-01-01

    This is the first Greek study presenting epidemiologic data on first-episode psychosis (FEP) patients in a defined catchment area. Data for first episode psychotic patients during a two-year period (2008 and 2009) were obtained by all the mental health providers in the area, public or private. A total of 132 FEP patients were examined in the 2-year period in the catchment area. Most of the patients (61.4%) were diagnosed and treated by private practicing psychiatrists. Statistical analysis showed no differences between the two sectors in terms of patients' age, gender, family and social status, profession and duration of untreated psychosis (median duration 6 months). Patients who were abusing substances and had no family psychiatric history were less likely been treated in the public sector. Immigrants comprised only a small proportion of the patients, probably because they have difficulties in accessing the mental health system.

  3. Single Electron Tunneling

    International Nuclear Information System (INIS)

    Ruggiero, Steven T.

    2005-01-01

    Financial support for this project has led to advances in the science of single-electron phenomena. Our group reported the first observation of the so-called ''Coulomb Staircase'', which was produced by tunneling into ultra-small metal particles. This work showed well-defined tunneling voltage steps of width e/C and height e/RC, demonstrating tunneling quantized on the single-electron level. This work was published in a now well-cited Physical Review Letter. Single-electron physics is now a major sub-field of condensed-matter physics, and fundamental work in the area continues to be conducted by tunneling in ultra-small metal particles. In addition, there are now single-electron transistors that add a controlling gate to modulate the charge on ultra-small photolithographically defined capacitive elements. Single-electron transistors are now at the heart of at least one experimental quantum-computer element, and single-electron transistor pumps may soon be used to define fundamental quantities such as the farad (capacitance) and the ampere (current). Novel computer technology based on single-electron quantum dots is also being developed. In related work, our group played the leading role in the explanation of experimental results observed during the initial phases of tunneling experiments with the high-temperature superconductors. When so-called ''multiple-gap'' tunneling was reported, the phenomenon was correctly identified by our group as single-electron tunneling in small grains in the material. The main focus throughout this project has been to explore single electron phenomena both in traditional tunneling formats of the type metal/insulator/particles/insulator/metal and using scanning tunneling microscopy to probe few-particle systems. This has been done under varying conditions of temperature, applied magnetic field, and with different materials systems. These have included metals, semi-metals, and superconductors. Amongst a number of results, we have

  4. Urban dogs in rural areas: Human-mediated movement defines dog populations in southern Chile.

    Science.gov (United States)

    Villatoro, Federico J; Sepúlveda, Maximiliano A; Stowhas, Paulina; Silva-Rodríguez, Eduardo A

    2016-12-01

    Management strategies for dog populations and their diseases include reproductive control, euthanasia and vaccination, among others. However, the effectiveness of these strategies can be severely affected by human-mediated dog movement. If immigration is important, then the location of origin of dogs imported by humans will be fundamental to define the spatial scales over which population management and research should apply. In this context, the main objective of our study was to determine the spatial extent of dog demographic processes in rural areas and the proportion of dogs that could be labeled as immigrants at multiple spatial scales. To address our objective we conducted surveys in households located in a rural landscape in southern Chile. Interviews allowed us to obtain information on the demographic characteristics of dogs in these rural settings, human influence on dog mortality and births, the localities of origin of dogs living in rural areas, and the spatial extent of human-mediated dog movement. We found that most rural dogs (64.1%) were either urban dogs that had been brought to rural areas (40.0%), or adopted dogs that had been previously abandoned in rural roads (24.1%). Some dogs were brought from areas located as far as ∼700km away from the study area. Human-mediated movement of dogs, especially from urban areas, seems to play a fundamental role in the population dynamics of dogs in rural areas. Consequently, local scale efforts to manage dog populations or their diseases are unlikely to succeed if implemented in isolation, simply because dogs can be brought from surrounding urban areas or even distant locations. We suggest that efforts to manage or study dog populations and related diseases should be implemented using a multi-scale approach. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Tunnel oxide passivated rear contact for large area n-type front junction silicon solar cells providing excellent carrier selectivity

    Directory of Open Access Journals (Sweden)

    Yuguo Tao

    2016-01-01

    Full Text Available Carrier-selective contact with low minority carrier recombination and efficient majority carrier transport is mandatory to eliminate metal-induced recombination for higher energy conversion efficiency for silicon (Si solar cells. In the present study, the carrier-selective contact consists of an ultra-thin tunnel oxide and a phosphorus-doped polycrystalline Si (poly-Si thin film formed by plasma enhanced chemical vapor deposition (PECVD and subsequent thermal crystallization. It is shown that the poly-Si film properties (doping level, crystallization and dopant activation anneal temperature are crucial for achieving excellent contact passivation quality. It is also demonstrated quantitatively that the tunnel oxide plays a critical role in this tunnel oxide passivated contact (TOPCON scheme to realize desired carrier selectivity. Presence of tunnel oxide increases the implied Voc (iVoc by ~ 125 mV. The iVoc value as high as 728 mV is achieved on symmetric structure with TOPCON on both sides. Large area (239 cm2 n-type Czochralski (Cz Si solar cells are fabricated with homogeneous implanted boron emitter and screen-printed contact on the front and TOPCON on the back, achieving 21.2% cell efficiency. Detailed analysis shows that the performance of these cells is mainly limited by boron emitter recombination on the front side.

  6. Ground penetrating radar measurements at the ONKALO research tunnel and eastern part of the Olkiluoto investigation area at July 2006

    International Nuclear Information System (INIS)

    Sipola, V.; Tarvainen, A.-M.

    2007-04-01

    Ground Penetrating Radar (GPR) measurements were carried out at ONKALO research site in summer 2006. Measurements included 400 metres of measurements inside ONKALO access tunnel and about 1800 metres of measurements on the ground, at the eastern parts of Olkiluoto investigation area. The purpose of the measurements done inside the access tunnel was to investigate, whether it would be possible to locate deformation structures or long fractures in the rock mass below the tunnel. The purpose of the measurements made on top of the ground was to investigate, whether it would be possible to locate glacio-isostatic faults from the soils. A secondary target was to try and locate the rock surface. The chosen part of ONKALO tunnel was measured using five different frequencies, which enabled comparing the results to each other. It also enabled getting a higher resolution picture of the top rock, than what would have been possible using only one low-frequency antenna. The on-the-ground measurements were measured using only one frequency. (orig.)

  7. Demographic monitoring of wild muriqui populations: Criteria for defining priority areas and monitoring intensity.

    Science.gov (United States)

    Strier, Karen B; Possamai, Carla B; Tabacow, Fernanda P; Pissinatti, Alcides; Lanna, Andre M; Rodrigues de Melo, Fabiano; Moreira, Leandro; Talebi, Maurício; Breves, Paula; Mendes, Sérgio L; Jerusalinsky, Leandro

    2017-01-01

    Demographic data are essential to assessments of the status of endangered species. However, establishing an integrated monitoring program to obtain useful data on contemporary and future population trends requires both the identification of priority areas and populations and realistic evaluations of the kinds of data that can be obtained under different monitoring regimes. We analyzed all known populations of a critically endangered primate, the muriqui (genus: Brachyteles) using population size, genetic uniqueness, geographic importance (including potential importance in corridor programs) and implementability scores to define monitoring priorities. Our analyses revealed nine priority populations for the northern muriqui (B. hypoxanthus) and nine for the southern muriqui (B. arachnoides). In addition, we employed knowledge of muriqui developmental and life history characteristics to define the minimum monitoring intensity needed to evaluate demographic trends along a continuum ranging from simple descriptive changes in population size to predictions of population changes derived from individual based life histories. Our study, stimulated by the Brazilian government's National Action Plan for the Conservation of Muriquis, is fundamental to meeting the conservation goals for this genus, and also provides a model for defining priorities and methods for the implementation of integrated demographic monitoring programs for other endangered and critically endangered species of primates.

  8. Demographic monitoring of wild muriqui populations: Criteria for defining priority areas and monitoring intensity.

    Directory of Open Access Journals (Sweden)

    Karen B Strier

    Full Text Available Demographic data are essential to assessments of the status of endangered species. However, establishing an integrated monitoring program to obtain useful data on contemporary and future population trends requires both the identification of priority areas and populations and realistic evaluations of the kinds of data that can be obtained under different monitoring regimes. We analyzed all known populations of a critically endangered primate, the muriqui (genus: Brachyteles using population size, genetic uniqueness, geographic importance (including potential importance in corridor programs and implementability scores to define monitoring priorities. Our analyses revealed nine priority populations for the northern muriqui (B. hypoxanthus and nine for the southern muriqui (B. arachnoides. In addition, we employed knowledge of muriqui developmental and life history characteristics to define the minimum monitoring intensity needed to evaluate demographic trends along a continuum ranging from simple descriptive changes in population size to predictions of population changes derived from individual based life histories. Our study, stimulated by the Brazilian government's National Action Plan for the Conservation of Muriquis, is fundamental to meeting the conservation goals for this genus, and also provides a model for defining priorities and methods for the implementation of integrated demographic monitoring programs for other endangered and critically endangered species of primates.

  9. Where can pixel counting area estimates meet user-defined accuracy requirements?

    Science.gov (United States)

    Waldner, François; Defourny, Pierre

    2017-08-01

    Pixel counting is probably the most popular way to estimate class areas from satellite-derived maps. It involves determining the number of pixels allocated to a specific thematic class and multiplying it by the pixel area. In the presence of asymmetric classification errors, the pixel counting estimator is biased. The overarching objective of this article is to define the applicability conditions of pixel counting so that the estimates are below a user-defined accuracy target. By reasoning in terms of landscape fragmentation and spatial resolution, the proposed framework decouples the resolution bias and the classifier bias from the overall classification bias. The consequence is that prior to any classification, part of the tolerated bias is already committed due to the choice of the spatial resolution of the imagery. How much classification bias is affordable depends on the joint interaction of spatial resolution and fragmentation. The method was implemented over South Africa for cropland mapping, demonstrating its operational applicability. Particular attention was paid to modeling a realistic sensor's spatial response by explicitly accounting for the effect of its point spread function. The diagnostic capabilities offered by this framework have multiple potential domains of application such as guiding users in their choice of imagery and providing guidelines for space agencies to elaborate the design specifications of future instruments.

  10. Re-Defining Traditional Bazaar Areas and Shade Structures Via Parametric Design Methods

    Directory of Open Access Journals (Sweden)

    Ahmet Emre Dinçer

    2017-12-01

    Full Text Available For the continuation of life, people created various equipment and goods. To create mutual benefits, they’ve exchanged the overpruduced items with different products. This has begun the shopping act. By the increased amount of transactions, a need of defined area for shopping have arisen.  For a temporary time, trading areas have been developed at different locations at a certain period. In the course of time, beside trading, these areas served as socio-cultural spaces where the human relations were established. Moreover, demand of being able to immediately access to needed goods have emerged. This situation made having a permanent trading area essential. Therefore, enclosed and permanent trade areas from bazaar, inn, bedesten, arasta to shopping malls have emerged. Next to all these trading areas, traditional bazaar areas keep being established. Nowadays, there is a need of providing some determined comfort conditions to the users for these street alley bazaars. Decreasing the effect of unfavorable weather conditions and providing supportive certain services and units (like WCs, security, cleanliness, etc. are some of them. As a fundamental solution, without disengaging the user relations with the outside, shade structures are generally provided. Shade structures can support cleaning and similar jobs by gathering and using rainwater besides its purpose of protecting the user from bad weather conditions. Application examples of these systems are gradually increasing. However, it is necessary to develop new approaches, in order to stop these proposed shade structures, become prototypes and to adapt the proposal to its environment and to increase diversity. In this study, a convenient shade structure and its alternatives, which are adapted to environmental conditions, were designed to create a sample model for other bazaar areas. In models, basically, folding design approaches were pursued. For production of these shade structure models

  11. [Using sequential indicator simulation method to define risk areas of soil heavy metals in farmland.

    Science.gov (United States)

    Yang, Hao; Song, Ying Qiang; Hu, Yue Ming; Chen, Fei Xiang; Zhang, Rui

    2018-05-01

    The heavy metals in soil have serious impacts on safety, ecological environment and human health due to their toxicity and accumulation. It is necessary to efficiently identify the risk area of heavy metals in farmland soil, which is of important significance for environment protection, pollution warning and farmland risk control. We collected 204 samples and analyzed the contents of seven kinds of heavy metals (Cu, Zn, Pb, Cd, Cr, As, Hg) in Zengcheng District of Guangzhou, China. In order to overcame the problems of the data, including the limitation of abnormal values and skewness distribution and the smooth effect with the traditional kriging methods, we used sequential indicator simulation method (SISIM) to define the spatial distribution of heavy metals, and combined Hakanson index method to identify potential ecological risk area of heavy metals in farmland. The results showed that: (1) Based on the similar accuracy of spatial prediction of soil heavy metals, the SISIM had a better expression of detail rebuild than ordinary kriging in small scale area. Compared to indicator kriging, the SISIM had less error rate (4.9%-17.1%) in uncertainty evaluation of heavy-metal risk identification. The SISIM had less smooth effect and was more applicable to simulate the spatial uncertainty assessment of soil heavy metals and risk identification. (2) There was no pollution in Zengcheng's farmland. Moderate potential ecological risk was found in the southern part of study area due to enterprise production, human activities, and river sediments. This study combined the sequential indicator simulation with Hakanson risk index method, and effectively overcame the outlier information loss and smooth effect of traditional kriging method. It provided a new way to identify the soil heavy metal risk area of farmland in uneven sampling.

  12. Evaluation of the source area of rooftop scalar measurements in London, UK using wind tunnel and modelling approaches.

    Science.gov (United States)

    Brocklehurst, Aidan; Boon, Alex; Barlow, Janet; Hayden, Paul; Robins, Alan

    2014-05-01

    The source area of an instrument is an estimate of the area of ground over which the measurement is generated. Quantification of the source area of a measurement site provides crucial context for analysis and interpretation of the data. A range of computational models exists to calculate the source area of an instrument, but these are usually based on assumptions which do not hold for instruments positioned very close to the surface, particularly those surrounded by heterogeneous terrain i.e. urban areas. Although positioning instrumentation at higher elevation (i.e. on masts) is ideal in urban areas, this can be costly in terms of installation and maintenance costs and logistically difficult to position instruments in the ideal geographical location. Therefore, in many studies, experimentalists turn to rooftops to position instrumentation. Experimental validations of source area models for these situations are very limited. In this study, a controlled tracer gas experiment was conducted in a wind tunnel based on a 1:200 scale model of a measurement site used in previous experimental work in central London. The detector was set at the location of the rooftop site as the tracer was released at a range of locations within the surrounding streets and rooftops. Concentration measurements are presented for a range of wind angles, with the spread of concentration measurements indicative of the source area distribution. Clear evidence of wind channeling by streets is seen with the shape of the source area strongly influenced by buildings upwind of the measurement point. The results of the wind tunnel study are compared to scalar concentration source areas generated by modelling approaches based on meteorological data from the central London experimental site and used in the interpretation of continuous carbon dioxide (CO2) concentration data. Initial conclusions will be drawn as to how to apply scalar concentration source area models to rooftop measurement sites and

  13. Large-area laser nano-texturing with user-defined patterns

    International Nuclear Information System (INIS)

    Li, L; Guo, W; Wang, Z B; Whitehead, D; Liu, Z; Luk'yanchuk, B

    2009-01-01

    Writing nano-sized features less than the diffraction limit of the lasers efficiently over a large area requires special technology development. This paper reports the use of a self-assembled particle lens array with near-field enhancement effect to write millions of nano-sized user-defined features, e.g. English letters, lines, curves, simultaneously by angular beam scanning. About a 5 mm × 5 mm area can be written with a single shot of a laser beam or few scans for up to 100 million identical features of nano or sub-micro scales. With the help of certain environmental conditions, such as the use of a suitable chemical solution in conjunction with the particle lens array, the characteristic of the features produced can be further controlled, including the generation of reversed (e.g. pits become hills and grooves become walls) features of laser-written patterns. The technical challenges, experimental findings and theoretical analysis/simulation are presented

  14. Proton tunneling in solids

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, J.

    1998-10-01

    The tunneling rate of the proton and its isotopes between interstitial sites in solids is studied theoretically. The phonons and/or the electrons in the solid have two effects on the tunneling phenomenon. First, they suppress the transfer integral between two neighbouring states. Second, they give rise to a finite lifetime of the proton state. Usually the second effect is large and the tunneling probability per unit time (tunneling rate) can be defined. In some cases, however, a coherent tunneling is expected and actually observed. (author)

  15. Proton tunneling in solids

    International Nuclear Information System (INIS)

    Kondo, J.

    1998-01-01

    The tunneling rate of the proton and its isotopes between interstitial sites in solids is studied theoretically. The phonons and/or the electrons in the solid have two effects on the tunneling phenomenon. First, they suppress the transfer integral between two neighbouring states. Second, they give rise to a finite lifetime of the proton state. Usually the second effect is large and the tunneling probability per unit time (tunneling rate) can be defined. In some cases, however, a coherent tunneling is expected and actually observed. (author)

  16. Closure Report for Corrective Action Unit 481: Area 12 T-Tunnel Conditional Release Storage Yard, Nevada Test Site, Nevada

    International Nuclear Information System (INIS)

    2008-01-01

    Corrective Action Unit (CAU) 481 is identified in the Federal Facility Agreement and Consent Order (FFACO) as Area 12 T-Tunnel Conditional Release Storage Yard. CAU 481 is located in Area 12 of the Nevada Test Site, which is approximately 65 miles northwest of Las Vegas, Nevada. This CAU consists of one Corrective Action Site (CAS), CAS 12-42-05, Housekeeping Waste. CAU 481 closure activities were conducted by the Defense Threat Reduction Agency from August 2007 through July 2008 according to the FFACO and Revision 3 of the Sectored Clean-up Work Plan for Housekeeping Category Waste Sites. Closure activities included removal and disposal of construction debris and low-level waste. Drained fluids, steel, and lead was recycled as appropriate. Waste generated during closure activities was appropriately managed and disposed.

  17. Design and planning of the exploratory tunnel in the Zapatoca area, Santander

    International Nuclear Information System (INIS)

    Bastidas O, E. A.

    1991-01-01

    The country at the moment doesn't have any exploitation of the mineral that gives the purest energy, as it is it the Uranium; the current investigation with regard to this radioactive material is in hands of the IAN (today Ingeominas) only entity that in its desire of giving to the country another form of decreasing the energy crisis has taken the decision of collaborating in the execution of the presented project. In this one can see in detailed form and white the steps that should be continued to make the exploratory tunnel; emphasis has been made since in the methods of prospecting of this mineral one doesn't have in the moment a knowledge to locate the uraniferous manifestations

  18. Tunneling current between graphene layers

    OpenAIRE

    Poklonski, Nikolai A.; Siahlo, Andrei I.; Vyrko, Sergey A.; Popov, Andrey M.; Lozovik, Yurii E.

    2013-01-01

    The physical model that allows to calculate the values of the tunneling current be-tween graphene layers is proposed. The tunneling current according to the pro-posed model is proportional to the area of tunneling transition. The calculated value of tunneling conductivity is in qualitative agreement with experimental data.

  19. Plastic Zone Analysis of Deep-Buried, Noncircular Tunnel and Application on the High-Speed Railway in the Karst Area

    Directory of Open Access Journals (Sweden)

    Hai Shi

    2017-01-01

    Full Text Available With the conformal mapping function provided by Verruijt, the outland of a noncircular tunnel can be mapped to a circular unit in the complex plane and then spread the analytic function into a Laurent series. The stress unified solution of oval and horseshoe cross section can be determined using Muskhelishvili’s complex variables function method. Subsequently, the solution can be taken into the Griffith strength failure criterion and determine the scale and shape of plastic zone in the tunnel surrounding rock. Aiming at the critical safety thickness between a concealed cave and tunnel in the karst area and determining whether the plastic zone of tunnel surrounding rock is connected with the plastic zone of cave as a judgment standard, the model of critical safety thickness among the concealed caves and tunnels is established. The numerical model is established in comparison with the computing method of rock plate critical safety thickness in actual engineering based on the Doumo tunnel engineering of Shanghai-Kunming (Guizhou segment high-speed railway. The following conclusions can be drawn: the analytical approximation method has less indexes, and the output of this method is approximately close to actual engineering and numerical analysis, in which it is reliable and rational.

  20. COMPARISON OF MULTI-SCALE DIGITAL ELEVATION MODELS FOR DEFINING WATERWAYS AND CATCHMENTS OVER LARGE AREAS

    Directory of Open Access Journals (Sweden)

    B. Harris

    2012-07-01

    Full Text Available Digital Elevation Models (DEMs allow for the efficient and consistent creation of waterways and catchment boundaries over large areas. Studies of waterway delineation from DEMs are usually undertaken over small or single catchment areas due to the nature of the problems being investigated. Improvements in Geographic Information Systems (GIS techniques, software, hardware and data allow for analysis of larger data sets and also facilitate a consistent tool for the creation and analysis of waterways over extensive areas. However, rarely are they developed over large regional areas because of the lack of available raw data sets and the amount of work required to create the underlying DEMs. This paper examines definition of waterways and catchments over an area of approximately 25,000 km2 to establish the optimal DEM scale required for waterway delineation over large regional projects. The comparative study analysed multi-scale DEMs over two test areas (Wivenhoe catchment, 543 km2 and a detailed 13 km2 within the Wivenhoe catchment including various data types, scales, quality, and variable catchment input parameters. Historic and available DEM data was compared to high resolution Lidar based DEMs to assess variations in the formation of stream networks. The results identified that, particularly in areas of high elevation change, DEMs at 20 m cell size created from broad scale 1:25,000 data (combined with more detailed data or manual delineation in flat areas are adequate for the creation of waterways and catchments at a regional scale.

  1. Comparison of Multi-Scale Digital Elevation Models for Defining Waterways and Catchments Over Large Areas

    Science.gov (United States)

    Harris, B.; McDougall, K.; Barry, M.

    2012-07-01

    Digital Elevation Models (DEMs) allow for the efficient and consistent creation of waterways and catchment boundaries over large areas. Studies of waterway delineation from DEMs are usually undertaken over small or single catchment areas due to the nature of the problems being investigated. Improvements in Geographic Information Systems (GIS) techniques, software, hardware and data allow for analysis of larger data sets and also facilitate a consistent tool for the creation and analysis of waterways over extensive areas. However, rarely are they developed over large regional areas because of the lack of available raw data sets and the amount of work required to create the underlying DEMs. This paper examines definition of waterways and catchments over an area of approximately 25,000 km2 to establish the optimal DEM scale required for waterway delineation over large regional projects. The comparative study analysed multi-scale DEMs over two test areas (Wivenhoe catchment, 543 km2 and a detailed 13 km2 within the Wivenhoe catchment) including various data types, scales, quality, and variable catchment input parameters. Historic and available DEM data was compared to high resolution Lidar based DEMs to assess variations in the formation of stream networks. The results identified that, particularly in areas of high elevation change, DEMs at 20 m cell size created from broad scale 1:25,000 data (combined with more detailed data or manual delineation in flat areas) are adequate for the creation of waterways and catchments at a regional scale.

  2. Ecosystem Services Modeling as a Tool for Defining Priority Areas for Conservation.

    Directory of Open Access Journals (Sweden)

    Gabriela Teixeira Duarte

    Full Text Available Conservationists often have difficulty obtaining financial and social support for protected areas that do not demonstrate their benefits for society. Therefore, ecosystem services have gained importance in conservation science in the last decade, as these services provide further justification for appropriate management and conservation of natural systems. We used InVEST software and a set of GIS procedures to quantify, spatialize and evaluated the overlap between ecosystem services-carbon stock and sediment retention-and a biodiversity proxy-habitat quality. In addition, we proposed a method that serves as an initial approach of a priority areas selection process. The method considers the synergism between ecosystem services and biodiversity conservation. Our study region is the Iron Quadrangle, an important Brazilian mining province and a conservation priority area located in the interface of two biodiversity hotspots, the Cerrado and Atlantic Forest biomes. The resultant priority area for the maintenance of the highest values of ecosystem services and habitat quality was about 13% of the study area. Among those priority areas, 30% are already within established strictly protected areas, and 12% are in sustainable use protected areas. Following the transparent and highly replicable method we proposed in this study, conservation planners can better determine which areas fulfill multiple goals and can locate the trade-offs in the landscape. We also gave a step towards the improvement of the habitat quality model with a topography parameter. In areas of very rugged topography, we have to consider geomorfometric barriers for anthropogenic impacts and for species movement and we must think beyond the linear distances. Moreover, we used a model that considers the tree mortality caused by edge effects in the estimation of carbon stock. We found low spatial congruence among the modeled services, mostly because of the pattern of sediment retention

  3. Ecosystem Services Modeling as a Tool for Defining Priority Areas for Conservation.

    Science.gov (United States)

    Duarte, Gabriela Teixeira; Ribeiro, Milton Cezar; Paglia, Adriano Pereira

    2016-01-01

    Conservationists often have difficulty obtaining financial and social support for protected areas that do not demonstrate their benefits for society. Therefore, ecosystem services have gained importance in conservation science in the last decade, as these services provide further justification for appropriate management and conservation of natural systems. We used InVEST software and a set of GIS procedures to quantify, spatialize and evaluated the overlap between ecosystem services-carbon stock and sediment retention-and a biodiversity proxy-habitat quality. In addition, we proposed a method that serves as an initial approach of a priority areas selection process. The method considers the synergism between ecosystem services and biodiversity conservation. Our study region is the Iron Quadrangle, an important Brazilian mining province and a conservation priority area located in the interface of two biodiversity hotspots, the Cerrado and Atlantic Forest biomes. The resultant priority area for the maintenance of the highest values of ecosystem services and habitat quality was about 13% of the study area. Among those priority areas, 30% are already within established strictly protected areas, and 12% are in sustainable use protected areas. Following the transparent and highly replicable method we proposed in this study, conservation planners can better determine which areas fulfill multiple goals and can locate the trade-offs in the landscape. We also gave a step towards the improvement of the habitat quality model with a topography parameter. In areas of very rugged topography, we have to consider geomorfometric barriers for anthropogenic impacts and for species movement and we must think beyond the linear distances. Moreover, we used a model that considers the tree mortality caused by edge effects in the estimation of carbon stock. We found low spatial congruence among the modeled services, mostly because of the pattern of sediment retention distribution.

  4. Spin-polarized scanning tunneling microscopy experiments on the rough surface of a polycrystalline NiFe film with a fine magnetic tip sensitive to a well-defined magnetization component

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, H., E-mail: matsu@phys.sci.hokudai.ac.jp [Department of Physics, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Nara, D.; Kageyama, R.; Honda, K.; Sato, T.; Kusanagi, K. [Department of Condensed Matter Physics, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Srinivasan, E. [Creative Research Institution (CRIS), Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan); Koike, K. [Department of Physics, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Creative Research Institution (CRIS), Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan)

    2016-03-15

    We developed a micrometer-sized magnetic tip integrated onto the write head of a hard disk drive for spin-polarized scanning tunneling microscopy (SP-STM) in the modulated tip magnetization mode. Using SP-STM, we measured a well-defined in-plane spin-component of the tunneling current of the rough surface of a polycrystalline NiFe film. The spin asymmetry of the NiFe film was about 1.3% within the bias voltage range of -3 to 1 V. We obtained the local spin component image of the sample surface, switching the magnetic field of the sample to reverse the sample magnetization during scanning. We also obtained a spin image of the rough surface of a polycrystalline NiFe film evaporated on the recording medium of a hard disk drive.

  5. Spin-polarized scanning tunneling microscopy experiments on the rough surface of a polycrystalline NiFe film with a fine magnetic tip sensitive to a well-defined magnetization component

    Directory of Open Access Journals (Sweden)

    H. Matsuyama

    2016-03-01

    Full Text Available We developed a micrometer-sized magnetic tip integrated onto the write head of a hard disk drive for spin-polarized scanning tunneling microscopy (SP-STM in the modulated tip magnetization mode. Using SP-STM, we measured a well-defined in-plane spin-component of the tunneling current of the rough surface of a polycrystalline NiFe film. The spin asymmetry of the NiFe film was about 1.3% within the bias voltage range of -3 to 1 V. We obtained the local spin component image of the sample surface, switching the magnetic field of the sample to reverse the sample magnetization during scanning. We also obtained a spin image of the rough surface of a polycrystalline NiFe film evaporated on the recording medium of a hard disk drive.

  6. Simulasi Virtual Local Area Network (VLAN Berbasis Software Defined Network (SDN Menggunakan POX Controller

    Directory of Open Access Journals (Sweden)

    Rohmat Tulloh

    2015-11-01

    Full Text Available VLAN (Virtual LAN merupakan sebuah teknologi yang dapat mengkonfigurasi jaringan logis independen dari struktur jaringan fisik. Hasil dari penelitian sebelumnya sudah diprediksi bahwa dibutuhkan Virtual Network yang akhirnya terciptalah VLAN. Namun paradigma jaringan saat ini tidak flexible, ketergantungan terhadap vendor sangat besar karena fungsi data plane dan control plane berada dalam satu paket device. SDN (Software defined network yang merupakan salahsatu evolusi teknologi jaringan sesuai dengan tuntutan yang berkembang dimana memisahkan fungsi data plane dan control plane pada suatu perangkat. POX Controller digunakan untuk men-simulasikan dan menguji Platform SDN (Software defined network. Pada penelitian ini menggunakan Openflow versi 1.0 untuk memasang header VLAN sehingga penelitian ini difokuskan untuk mengevaluasi performa forwarding VLAN yang memanfaatkan Openflow sebagai control plane dapat berfungsi dengan baik. Hasil penelitian ini mengusulkan penerapan karakteristik teknologi VLAN pada SDN karena telah berjalan dengan benar sesuai hasil pengujian konektifitas, verifikasi dan keamanan. Kemudian hasil pengujian lanjutan untuk melihat pengaruh SDN dengan skenario penambahan jumlah VLAN ID didapatkan bahwa set-up time akan bertambah seiring meningkatnya jumlah host dan dengan menggunakan protokol OpenFlow, latency yang terjadi di jaringan dapat dipantau dengan parameter round trip time (RTT yang stabil direntang 0,2 sampai 6 second walaupun jumlah vlan_id dan background traffic bertambah.

  7. 41 CFR 101-39.208 - Vehicles removed from defined areas.

    Science.gov (United States)

    2010-07-01

    ... VEHICLES 39-INTERAGENCY FLEET MANAGEMENT SYSTEMS 39.2-GSA Interagency Fleet Management System Services... operated outside the geographical area served by the issuing GSA IFMS fleet management center. However... shall notify the issuing GSA IFMS fleet management center of the following: (1) The location at which...

  8. Corrective Action Decision Document/Closure Report for Corrective Action Unit 383: Area E-Tunnel Sites, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2010-03-15

    This Corrective Action Decision Document/Closure Report (CADD/CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 383, Area 12 E-Tunnel Sites, which is the joint responsibility of DTRA and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO). This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada, the DOE, and the U.S. Department of Defense. Corrective Action Unit 383 is comprised of three Corrective Action Sites (CASs) and two adjacent areas: • CAS 12-06-06, Muckpile • CAS 12-25-02, Oil Spill • CAS 12-28-02, Radioactive Material • Drainage below the Muckpile • Ponds 1, 2, and 3 The purpose of this CADD/CR is to provide justification and documentation to support the recommendation for closure with no further corrective action, by placing use restrictions at the three CASs and two adjacent areas of CAU 383.

  9. Construction of transmission pipeline across Osaka bay area -pipeline construction by shield tunnel under seabed-; Construction d'un gazoduc dans la zone de la baie d'Osaka - tunnel de protection sous-marin

    Energy Technology Data Exchange (ETDEWEB)

    Takashi, AIhara [Osaka Gas Co., Ltd (Japan)

    2000-07-01

    Osaka Gas has been constructing a transmission gas pipeline across Osaka Bay Area with Osaka Port that has busy traffic. The company met several technical problems on the construction-design with measures against the subsidence of reclaimed land, anti-seismic measures, for example, in designing the pipeline construction by shield tunnel under seabed. This paper introduces the solutions to the technical problems. (authors)

  10. Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

    International Nuclear Information System (INIS)

    Cleland, A.N.

    1991-04-01

    Experiments investigating the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very small capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters; the tunneling rate in the moderately damped (Q ∼ 1) junction is seen to be reduced by a factor of 300 from that predicted for an undamped junction. The phase is seen to be a good quantum-mechanical variable. The experiments on small capacitance tunnel junctions extend the measurements on the larger-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wavefunction has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias. I present the first clear observation of the Coulomb blockade in single junctions. The electrical environment of the tunnel junction, however, strongly affects the behavior of the junction: higher resistance leads are observed to greatly sharpen the Coulomb blockade over that seen with lower resistance leads. I present theoretical descriptions of how the environment influences the junctions; comparisons with the experimental results are in reasonable agreement

  11. Defining Indicators and Standards for Tourism Impacts in Protected Areas: Cape Range National Park, Australia

    Science.gov (United States)

    Moore, Susan A.; Polley, Amanda

    2007-03-01

    Visitors’ perceptions of impacts and acceptable standards for environmental conditions can provide essential information for the sustainable management of tourist destinations, especially protected areas. To this end, visitor surveys were administered during the peak visitor season in Cape Range National Park, on the northwest coast of Western Australia and adjacent to the iconic Ningaloo Reef. The central focus was visitors’ perceptions regarding environmental conditions and standards for potential indicators. Conditions considered of greatest importance in determining visitors’ quality of experience included litter, inadequate disposal of human waste, presence of wildlife, levels of noise, and access to beach and ocean. Standards were determined, based on visitors’ perceptions, for a range of site-specific and non-site-specific indicators, with standards for facilities (e.g., acceptable number of parking bays, signs) and for negative environmental impacts (e.g., levels of littering, erosion) sought. The proposed standards varied significantly between sites for the facilities indicators; however, there was no significant difference between sites for environmental impacts. For the facilities, the standards proposed by visitors were closely related to the existing situation, suggesting that they were satisfied with the status quo. These results are considered in the context of current research interest in the efficacy of visitor-derived standards as a basis for protected area management.

  12. Use of probabilistic risk assessments to define areas of possible exemption from regulatory requirements

    International Nuclear Information System (INIS)

    Thompson, C.A.; Carlson, D.; Kolaczkowski, A.; LaChance, J.

    1988-01-01

    The Risk-Based Licensing Program (RBLP) was sponsored by the Department of Energy for the purpose of establishing and demonstrating an approach for identifying potential areas for exemption from current regulatory requirements in the licensing of nuclear power plants. Such an approach could assist in the improvement of the regulatory process for both current and future nuclear plant designs. Use of the methodology could result in streamlining the regulatory process by eliminating unnecessarily detailed reviews of portions of a plant design not important to risk. The RBLP methodology utilizes probabilistic risk assessments, (PRAs), which are required of all future applicants for nuclear power plant licenses. PRA results are used as a screening tool to determine the risk significance of various plant features which are correlated to the risk importance of regulations to identify potential areas for regulatory exemption. Additional consideration is then given to non-risk factors in the final determination of exemption candidates. The RBLP methodology was demonstrated using an existing PRA. The results of the demonstration are highlighted. 10 refs

  13. Defining indicators and standards for tourism impacts in protected areas: Cape Range National Park, Australia.

    Science.gov (United States)

    Moore, Susan A; Polley, Amanda

    2007-03-01

    Visitors' perceptions of impacts and acceptable standards for environmental conditions can provide essential information for the sustainable management of tourist destinations, especially protected areas. To this end, visitor surveys were administered during the peak visitor season in Cape Range National Park, on the northwest coast of Western Australia and adjacent to the iconic Ningaloo Reef. The central focus was visitors' perceptions regarding environmental conditions and standards for potential indicators. Conditions considered of greatest importance in determining visitors' quality of experience included litter, inadequate disposal of human waste, presence of wildlife, levels of noise, and access to beach and ocean. Standards were determined, based on visitors' perceptions, for a range of site-specific and non-site-specific indicators, with standards for facilities (e.g., acceptable number of parking bays, signs) and for negative environmental impacts (e.g., levels of littering, erosion) sought. The proposed standards varied significantly between sites for the facilities indicators; however, there was no significant difference between sites for environmental impacts. For the facilities, the standards proposed by visitors were closely related to the existing situation, suggesting that they were satisfied with the status quo. These results are considered in the context of current research interest in the efficacy of visitor-derived standards as a basis for protected area management.

  14. Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

    International Nuclear Information System (INIS)

    Cleland, A.N.

    1991-01-01

    Experiments investigated the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very-small-capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson-phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters. The experiments on small-capacitance tunnel junctions extend the measurements on the large-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wave function has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias

  15. Physiological intracellular crowdedness is defined by perimeter to area ratio of subcellular compartments

    Directory of Open Access Journals (Sweden)

    Noriko eHiroi

    2012-07-01

    Full Text Available The intracellular environment is known to be a crowded and inhomogeneous space. Such an in vivo environment differs from a well-diluted, homogeneous environment for biochemical reactions. However, the effects of both crowdedness and the inhomogeneity of environment on the behavior of a mobile particle have not yet been investigated sufficiently. As described in this paper, we constructed artificial reaction spaces with fractal models, which are assumed to be non-reactive solid obstacles in a reaction space with crevices that function as operating ranges for mobile particles threading the space. Because of the homogeneity of the structures of artificial reaction spaces, the models succeeded in reproducing the physiological fractal dimension of solid structures with a smaller number of non-reactive obstacles than in the physiological condition. This incomplete compatibility was mitigated when we chose a suitable condition of a perimeter-to-area ratio of the operating range to our model. Our results also show that a simulation space is partitioned into convenient reaction compartments as an in vivo environment with the exact amount of solid structures estimated from TEM images. The characteristics of these compartments engender larger mean square displacement of a mobile particle than that of particles in smaller compartments. Subsequently, the particles start to show confined particle-like behavior. These results are compatible with our previously presented results, which predicted that a physiological environment would produce quick-response and slow-exhaustion reactions.

  16. Eskers and bedrock gorges (tunnel valleys in the Pakasaivo area, western Finnish Lapland

    Directory of Open Access Journals (Sweden)

    Peter Johansson

    2003-01-01

    Full Text Available Studies of the deglaciation of the last Scandinavian Ice Sheet, including the behavior of the ice sheet and meltwater activity, were conducted in the vicinity of the Pakasaivo canyon lake, located in western Finnish Lapland. Pakasaivo itself, a circular basin up to 100 m deep, was formed in the broken bedrock by glacial erosion and meltwater streams. It was originally related to a former subglacial meltwater system, including the deep Keinokursu gorge. Both this gorge and the Pakasaivo canyon lake were formed subglacially duringan early stage of deglaciation. It was characterized by intense meltwater erosion, which in Pakasaivo also seems to have generated a strong whirl. Steep-crested esker ridges were subsequently deposited; subaerial meltwater activity then followed. Finally the meltwaterwas discharged from the ice-dammed lake north of the area and passed through the Pakasaivo canyon to the ice-free areas. This caused additional intense erosion of the canyon floor and walls, and the deep circular basin is highly similar to a plunge pool formed at the base of a cataract.

  17. [The cross-sectional area of the median nerve by sonography in the diagnosis of carpal tunnel syndrome].

    Science.gov (United States)

    Sabag-Ruiz, Enrique; Higuera-Lugo, Cirilo Omar; Ornelas-Aguirre, José Manuel; Gómez-Alcalá, Alejandro V

    2009-01-01

    To measure the median nerve cross-sectional area (MNCSA) at the carpal tunnel (CT) level by sonography (S) in a Mexican population. A comparative cross-sectional design study with a nonprobabilistic sampling with 50 women and 50 men in good health were submitted for measuring MNCSA at the level of the CT. Other variables like sex; side and degree of daily hand activity were also studied. The analysis was made by descriptive statistics, and Mann-Whitney U or Kruskal-Wallis tests. The mean MNCSA was 0.063 +/- 0.015 cm(2), in women; in men it was 0.072 +/- 0.018 cm(2); the difference was significant (p right side and 0.060 cm(2) in the left (90th percentile for both hands of 0.084 cm(2)); in men, it was of 0.070 cm(2) in the right hand and of 0.069 cm(2) in the left (90th percentile for both hands of 0.097 cm(2)). The difference between women and men was significant in each side, but not between right and left hands (p = 0.21). There was no correlation between age and MNCSA on either side, or with hand activity. A MNCSA value of 0.1 cm(2) for men and 0.09 cm(2) for women is proposed as a standard parameter for the Mexican population.

  18. The problem of defining the limits of protected areas in Ukraine regarding to the sustainable land management

    Directory of Open Access Journals (Sweden)

    Б. В. Даниленко

    2015-11-01

    Full Text Available Nowadays all over the world new protected areas are being created. In Ukraine this process is developed within European programs. During the years of independence many new protected areas were created. Large amount of them were included in so called Ukrainian ecological network that ought to be built in 2015. This network is connected with the European ecological network. The governmental reports show high level of the execution of the programs of developing of the protected areas. But in reality we can see that many of new protected areas do not have the determined limits. This results in dangerous human occupation of such lands. Businessmen understand that occupation will be impossible soon. And they think that such protected areas are proclaimed but yet not really exist. And most of Ukrainian courts agree with this. Recent research and publications analyses. Research of management of protected areas through legal means in Ukraine was made by many Ukrainian scientists (V.I. Andreytsev, A.P. Hetman, M.V. Shulga, P.F. Kulynich, A.M. Myroshnychenko and others. At the same time the scientists have not paid enough attention to the problem of defining the limits of protected areas which is now really a great legal problem in Ukraine. Paper objective is the legal problem of defining the limits of protected areas in Ukraine regarding to the sustainable land management. Paper main body. Generally, protected areas are understood to be those in which human occupation or at least the exploitation of resources is limited. The definition that has been widely accepted across regional and global frameworks has been provided by the International Union for Conservation of Nature (IUCN in its categorization guidelines for protected areas. The definition is as follows: "A clearly defined geographical space, recognized, dedicated and managed, through legal or other effective means, to achieve the long-term conservation of nature with associated ecosystem services

  19. Scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Binnig, G.; Rohrer, H.

    1983-01-01

    Based on vacuum tunneling, a novel type of microscope, the scanning tunneling microscope (STM) was developed. It has an unprecedented resolution in real space on an atomic scale. The authors review the important technical features, illustrate the power of the STM for surface topographies and discuss its potential in other areas of science and technology. (Auth.)

  20. Proposal to negotiate amendments to an existing contract for the supply of steel structures for the LHC shafts, tunnels, caverns and experimental areas

    CERN Document Server

    2005-01-01

    This document concerns the proposal to negotiate amendments to an existing contract for the supply of additional steel structures for the LHC shafts, tunnels, caverns and experimental areas. For the reasons explained in this document, the Finance Committee is invited to approve amendments to the existing contract with the firm INIZIATIVE INDUSTRIALI (IT) for the supply of additional steel structures for the LHC shafts, tunnels, caverns and experimental areas for an amount of 500 000 euros (775 000 Swiss francs), subject to revision for inflation, bringing the total to 6 525 745 euros (10 114 905 Swiss francs), subject to revision for inflation. The amounts in Swiss francs have been calculated using the present rate of exchange.

  1. Interaction between groundwater and TBM (Tunnel Boring Machine) excavated tunnels

    OpenAIRE

    Font Capó, Jordi

    2012-01-01

    A number of problems, e.g. sudden inflows are encountered during tunneling under the piezometric level, especially when the excavation crosses high transmissivity areas. These inflows may drag materials when the tunnel crosses low competent layers, resulting in subsidence, chimney formation and collapses. Moreover, inflows can lead to a decrease in head level because of aquifer drainage. Tunnels can be drilled by a tunnel boring machine (TBM) to minimize inflows and groundwater impacts, restr...

  2. Scanning tunneling microscope nanoetching method

    Science.gov (United States)

    Li, Yun-Zhong; Reifenberger, Ronald G.; Andres, Ronald P.

    1990-01-01

    A method is described for forming uniform nanometer sized depressions on the surface of a conducting substrate. A tunneling tip is used to apply tunneling current density sufficient to vaporize a localized area of the substrate surface. The resulting depressions or craters in the substrate surface can be formed in information encoding patterns readable with a scanning tunneling microscope.

  3. Wind tunnel investigation on the retention of air pollutants in three-dimensional recirculation zones in urban areas

    Science.gov (United States)

    Gomes, Marcos Sebastião de Paula; Isnard, André Augusto; Pinto, José Maurício do Carmo

    The article discusses an experimental investigation of turbulent dispersion processes in a typical three-dimensional urban geometry, in reduced scale, in neutrally stable conditions. Wind tunnel experiments were carried out for characterizing the flow and the dispersion of a pollutant around a scaled model (1:400) of a group of eight 10-floor buildings surrounding a square. The situation corresponded to the dispersion of fine inertialess particles released from a line source positioned upstream of the urban geometry. After the sudden interruption of the source generation, the particles persisted in the recirculation cavity between the buildings, with the concentration decaying exponentially with time. This is in accordance with previous works on the dispersion process around bluff bodies of different shapes [e.g., Humphries and Vincent, 1976. An experimental investigation of the detention of airborne smoke in the wake bubble behind a disk. Journal of Fluid Mechanics 73, 453-464; Vincent, 1977. Model experiments on the nature of air pollution transport near buildings. Atmospheric Environment 11, 765-774; Fackrell, 1984. Parameters characterizing dispersion in the near wake of buildings. Journal of Wind Engineering and Industrial Aerodynamics 16, 97-118]. The main parameter in the investigation was the characteristic time constant for the concentration decay. The measurements of the variation in the concentration of the fine particles were performed by means of a photo-detection technique based on the attenuation of light. The velocity fields were evaluated with the particle image velocimetry (PIV) technique. The dimensionless residence time H for the particles ( H= τU/ L, where τ is the time constant for the concentration decay, U the free-stream velocity, and L is a characteristic dimension for the urban geometry, as defined by Humphries and Vincent [1976. An experimental investigation of the detention of airborne smoke in the wake bubble behind a disk. Journal

  4. 16 February 2012 - Chinese Taipei Ambassador to Switzerland F. Hsieh in the ATLAS visitor centre, ATLAS experimental area and LHC tunnel at Point 1 with Collaboration Deputy Sookesperson A. Lankford, throughout accompanied by International Relations Adviser R. Voss.

    CERN Multimedia

    Jean-Claude Gadmer

    2012-01-01

    16 February 2012 - Chinese Taipei Ambassador to Switzerland F. Hsieh in the ATLAS visitor centre, ATLAS experimental area and LHC tunnel at Point 1 with Collaboration Deputy Sookesperson A. Lankford, throughout accompanied by International Relations Adviser R. Voss.

  5. 27 September 2013 -Lithuanian Minister of Culture Š. Birutis in the LHC tunnel with International Relations Adviser T. Kurtyka and visiting CMS experimental area with Deputy Spokesperson T. Camporesi. Also present: V. Rapsevicius, CMS Collaboration.

    CERN Multimedia

    Laurent Egli

    2013-01-01

    27 September 2013 -Lithuanian Minister of Culture Š. Birutis in the LHC tunnel with International Relations Adviser T. Kurtyka and visiting CMS experimental area with Deputy Spokesperson T. Camporesi. Also present: V. Rapsevicius, CMS Collaboration.

  6. 28 June 2012 - Members of the European Brain Council led by President Mary Baker visiting the LHC tunnel at Point 5 with Technology Department Group Leader L. Bottura and CMS experimental area with Run Coordinator M. Chamizo-Llatas.

    CERN Multimedia

    Jean-Claude Gadmer

    2012-01-01

    28 June 2012 - Members of the European Brain Council led by President Mary Baker visiting the LHC tunnel at Point 5 with Technology Department Group Leader L. Bottura and CMS experimental area with Run Coordinator M. Chamizo-Llatas.

  7. 14 December 2011 - Czech Republic Delegation to CERN Council and Finance Committees visiting ATLAS experimental area, LHC tunnel and ATLAS visitor centre with Former Collaboration Spokesperson P. Jenni, accompanied by Physicist R. Leitner and Swiss student A. Lister.

    CERN Multimedia

    Estelle Spirig

    2011-01-01

    14 December 2011 - Czech Republic Delegation to CERN Council and Finance Committees visiting ATLAS experimental area, LHC tunnel and ATLAS visitor centre with Former Collaboration Spokesperson P. Jenni, accompanied by Physicist R. Leitner and Swiss student A. Lister.

  8. Cloud-Centric and Logically Isolated Virtual Network Environment Based on Software-Defined Wide Area Network

    Directory of Open Access Journals (Sweden)

    Dongkyun Kim

    2017-12-01

    Full Text Available Recent development of distributed cloud environments requires advanced network infrastructure in order to facilitate network automation, virtualization, high performance data transfer, and secured access of end-to-end resources across regional boundaries. In order to meet these innovative cloud networking requirements, software-defined wide area network (SD-WAN is primarily demanded to converge distributed cloud resources (e.g., virtual machines (VMs in a programmable and intelligent manner over distant networks. Therefore, this paper proposes a logically isolated networking scheme designed to integrate distributed cloud resources to dynamic and on-demand virtual networking over SD-WAN. The performance evaluation and experimental results of the proposed scheme indicate that virtual network convergence time is minimized in two different network models such as: (1 an operating OpenFlow-oriented SD-WAN infrastructure (KREONET-S which is deployed on the advanced national research network in Korea, and (2 Mininet-based experimental and emulated networks.

  9. 78 FR 46117 - National Tunnel Inspection Standards

    Science.gov (United States)

    2013-07-30

    ... busiest vehicular tunnel in the world. The Fort McHenry Tunnel handles a daily traffic volume of more than... vehicular, transit, and rail tunnels in the New York City metropolitan area. Although it is still too early... congestion along alternative routes, and save users both dollars and fuel. If these tunnels were closed due...

  10. Tunneling works. Tunnel koji

    Energy Technology Data Exchange (ETDEWEB)

    Higo, M [Hazam Gumi, Ltd., Tokyo (Japan)

    1991-10-25

    A mountain tunneling method for rock-beds used to be applied mainly to construction works in the mountains under few restrictions by environmental problems. However, construction works near residential sreas have been increasing. There are such enviromental problems due to tunneling works as vibration, noise, lowering of ground-water level, and influences on other structures. This report mainly describes the measurement examples of vibration and noise accompanied with blasting and the effects of the measures to lessen such influences. When the tunneling works for the railroad was carried out on the natural ground mainly composed of basalt, vibration of the test blasting was measured at three stations with piezoelectric accelerometers. Then, ordinary blasting, mutistage blasting, and ABM blasting methods were used properly besed on the above results, and only a few complaints were made. In the different works, normal noise and low-frequency sound were mesured at 22 stations around the pit mouth. As countermeasures for noise, sound-proof sheets, walls, and single and double doors were installed and foundto be effective. 1 ref., 6 figs., 1 tab.

  11. The combination of analytical and statistical method to define polygonal ship domain and reflect human experiences in estimating dangerous area

    Directory of Open Access Journals (Sweden)

    Gia Huy Dinh

    2016-06-01

    Full Text Available The paper suggests a new method of collision avoidance stemming from the concept of the polygonal target ship domain. Since the last century, we have witnessed the current typical ship domains classified and described. In this proposition, firstly, the domain is a geometrical manner which is used in both analytical and statistical method, resulting in the signification of practical application and simulation. Secondly, such domain will be applied to target ship under the combination of two separated parts: “Blocking area” and “Action area” in order to define the area where the ship must keep outside and how the actions to avoid collision can be generated. Thirdly, the concept has suggested the number of mathematical models for different approaching encounters, including head-on, overtaking and crossing situation. Finally, the parameters of turning circle of the ship can be proposed in determining the size of the domain. Statistical evidences indicate that this method reflects a crew's real habit and psychological in maneuvering. As the result, simple domain is shaped like imagination of sailors, but more accurate in calculating boundary. It promises an effective solution for automatic collision avoidance method. The next researches of this paper have achieved positive results in finding shortest route for avoiding collision. Moreover, while using statistical methods, classical researches face a serious problem in a wide application with different areas, this concept can make up a beneficial solution for the popular application. The numerous ship domains which are in previous researches will be carried out to compare and point out the simplification and effectiveness of the new method in practice.

  12. 1st February 2011-CERN Cultural Board for Engaging with the Arts, visiting CMS experimental area and LHC Tunnel at Point 5

    CERN Multimedia

    Michael Hoch

    2011-01-01

    Photo 1-4: Visit to CMS Control Room with G. Tonelli,CMS Collaboration Spokesperson Photo 5-9,16-20:CMS experimental area Photo 10-15:LHC Tunnel at Point 5 Photo 21:F. Madlener,Director of IRCAM Paris+S. Dorny,Director-General Lyon Opera House+C. Bollman,Art by Genève+M. Doser,AEgIS Collaboration Spokesperson,Former Physics Department Deputy Head+A. Koek,International Arts Development+G. Tonelli+M. Monje Cano,Arts Development Assistant (part-time work experience)+B. Ruf,Director of Kunsthalle Zürich

  13. Empowerment Zones and Enterprise Districts, Municipal Service Area - area defined by Ordinance that provides for the City jurisdiction related to development and future growth, Published in 2009, 1:24000 (1in=2000ft) scale, City of Topeka Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Empowerment Zones and Enterprise Districts dataset current as of 2009. Municipal Service Area - area defined by Ordinance that provides for the City jurisdiction...

  14. EMULACIÓN DE ESCENARIOS VIRTUALES, EN UNA SDWLAN (SOFTWARE DEFINED WIRELESS LOCAL AREA NETWORK, DE UN CAMPUS UNIVERSITARIO

    Directory of Open Access Journals (Sweden)

    Gerlyn Duarte

    2015-07-01

    Full Text Available Las redes definidas por software (SDN = Software Defined Network es una arquitectura de red emergente que se destaca como una tecnología capaz de ofrecer un control más flexible y dinámico a la hora de gestionar el diseño y funciones de la red, donde se separan los planos de control y enrutamiento. Esto permite la centralización de los controles de la red basada en software. Se puede decir que es posible tener flexibilidad y rapidez al momento de configurar, implementar y administrar diferentes protocolos personalizados para los requerimientos de distintas redes. Actualmente, en una red convencional, cada conmutador y/o enrutador tienen software propietario que le dice qué hacer. SDN se centra principalmente en la parte cableada de la red de datos. Sin embargo, todas las ventajas de las SDN sólo se obtienen si se logra abarcar la totalidad de la infraestructura, desde el centro de datos al extremo de la red, permitiendo extender todos los beneficios de SDN hasta la red inalámbrica, para conseguir a su vez una red inalámbrica de área local definida por software (SDWLAN = Software Define Wireless Local Area Network. Es por ello que en el presente trabajo, se emuló parte de una SDWLAN de un campus universitario para observar la factibilidad de implementar SDN en la misma. Para la emulación se utilizó una variante del emulador Mininet que permite trabajar con redes inalámbricas. De igual forma, se efectuaron mediciones del ancho de banda de las SDWLAN emuladas, así como la interconectividad entre ellas. Se evidenció la facilidad y el rendimiento de trabajar con las herramientas de emulación de SDWLAN empleadas, permitiendo de igual forma la estructuración de distintas topologías de SDWLAN. Se comprobó que el emulador, el cual está aún en la fase beta, permite interactuar y ejecutar cualquier proceso como si se ejecutara directamente en un equipo con GNU/Linux de forma eficaz.

  15. Defining Face Perception Areas in the Human Brain: A Large-Scale Factorial fMRI Face Localizer Analysis

    Science.gov (United States)

    Rossion, Bruno; Hanseeuw, Bernard; Dricot, Laurence

    2012-01-01

    A number of human brain areas showing a larger response to faces than to objects from different categories, or to scrambled faces, have been identified in neuroimaging studies. Depending on the statistical criteria used, the set of areas can be overextended or minimized, both at the local (size of areas) and global (number of areas) levels. Here…

  16. Supramolecular tunneling junctions

    NARCIS (Netherlands)

    Wimbush, K.S.

    2012-01-01

    In this study a variety of supramolecular tunneling junctions were created. The basis of these junctions was a self-assembled monolayer of heptathioether functionalized ß-cyclodextrin (ßCD) formed on an ultra-flat Au surface, i.e., the bottom electrode. This gave a well-defined hexagonally packed

  17. Corrective Action Decision Document/Closure Report for Corrective Action Unit 478: Area 12 T-Tunnel Ponds, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2010-03-15

    This Corrective Action Decision Document (CADD)/Closure Report (CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 478, Area 12 T-Tunnel Ponds. This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada, the U.S. Department of Energy (DOE), and the U.S. Department of Defense. Corrective Action Unit 478 is comprised of one corrective action site (CAS): • 12-23-01, Ponds (5) RAD Area The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure in place with use restrictions for CAU 478.

  18. Calibration of a four-hole pyramid probe and area traverse measurements in a short-duration transonic turbine cascade tunnel

    Science.gov (United States)

    Main, A. J.; Day, C. R. B.; Lock, G. D.; Oldfield, M. L. G.

    1996-08-01

    A four-hole pyramid probe has been calibrated for use in a short-duration transonic turbine cascade tunnel. The probe is used to create area traverse maps of total and static pressure, and pitch and yaw angles of the flow downstream of a transonic annular cascade. This data is unusual in that it was acquired in a short-duration (5 s of run time) annular cascade blowdown tunnel. A four-hole pyramid probe was used which has a 2.5 mm section head, and has the side faces inclined at 60° to the flow to improve transonic performance. The probe was calibrated in an ejector driven, perforated wall transonic tunnel over the Mach number range 0.5 1.2, with pitch angles from -20° to + 20° and yaw angles from-23° to +23°. A computer driven automatic traversing mechanism and data collection system was used to acquire a large probe calibration matrix (˜ 10,000 readings) of non dimensional pitch, yaw, Mach number, and total pressure calibration coefficients. A novel method was used to transform the probe calibration matrix of the raw coefficients into a probe application matrix of the physical flow variables (pitch, yaw, Mach number etc.). The probe application matrix is then used as a fast look-up table to process probe results. With negligible loss of accuracy, this method is faster by two orders of magnitude than the alternative of global interpolation on the raw probe calibration matrix. The blowdown tunnel (mean nozzle guide vane blade ring diameter 1.1 m) creates engine representative Reynolds numbers, transonic Mach numbers and high levels (≈ 13%) of inlet turbulence intensity. Contours of experimental measurements at three different engine relevant conditions and two axial positions have been obtained. An analysis of the data is presented which includes a necessary correction for the finite velocity of the probe. Such a correction is non trivial for the case of fast moving probes in compressible flow.

  19. Typical Underwater Tunnels in the Mainland of China and Related Tunneling Technologies

    Directory of Open Access Journals (Sweden)

    Kairong Hong

    2017-12-01

    Full Text Available In the past decades, many underwater tunnels have been constructed in the mainland of China, and great progress has been made in related tunneling technologies. This paper presents the history and state of the art of underwater tunnels in the mainland of China in terms of shield-bored tunnels, drill-and-blast tunnels, and immersed tunnels. Typical underwater tunnels of these types in the mainland of China are described, along with innovative technologies regarding comprehensive geological prediction, grouting-based consolidation, the design and construction of large cross-sectional tunnels with shallow cover in weak strata, cutting tool replacement under limited drainage and reduced pressure conditions, the detection and treatment of boulders, the construction of underwater tunnels in areas with high seismic intensity, and the treatment of serious sedimentation in a foundation channel of immersed tunnels. Some suggestions are made regarding the three potential great strait-crossing tunnels—the Qiongzhou Strait-Crossing Tunnel, Bohai Strait-Crossing Tunnel, and Taiwan Strait-Crossing Tunnel—and issues related to these great strait-crossing tunnels that need further study are proposed. Keywords: Underwater tunnel, Strait-crossing tunnel, Shield-bored tunnel, Immersed tunnel, Drill and blast

  20. Ultra-low switching energy and scaling in electric-field-controlled nanoscale magnetic tunnel junctions with high resistance-area product

    Energy Technology Data Exchange (ETDEWEB)

    Grezes, C.; Alzate, J. G.; Cai, X.; Wang, K. L. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Ebrahimi, F.; Khalili Amiri, P. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Inston, Inc., Los Angeles, California 90024 (United States); Katine, J. A. [HGST, Inc., San Jose, California 95135 (United States); Langer, J.; Ocker, B. [Singulus Technologies AG, Kahl am Main 63796 (Germany)

    2016-01-04

    We report electric-field-induced switching with write energies down to 6 fJ/bit for switching times of 0.5 ns, in nanoscale perpendicular magnetic tunnel junctions (MTJs) with high resistance-area product and diameters down to 50 nm. The ultra-low switching energy is made possible by a thick MgO barrier that ensures negligible spin-transfer torque contributions, along with a reduction of the Ohmic dissipation. We find that the switching voltage and time are insensitive to the junction diameter for high-resistance MTJs, a result accounted for by a macrospin model of purely voltage-induced switching. The measured performance enables integration with same-size CMOS transistors in compact memory and logic integrated circuits.

  1. Corrective Action Decision Document/Closure Report for Corrective Action Unit 476: Area 12 T-Tunnel Muckpile, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2010-03-15

    This Corrective Action Decision Document (CADD)/Closure Report (CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 476, Area 12 T-Tunnel Muckpile. This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada, the U.S. Department of Energy, and the U.S. Department of Defense. Corrective Action Unit 476 is comprised of one Corrective Action Site (CAS): • 12-06-02, Muckpile The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure in place with use restrictions for CAU 476.

  2. Characterization of magnetic tunnel junction test pads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Kjær, Daniel; Nielsen, Peter Folmer

    2015-01-01

    We show experimentally as well as theoretically that patterned magnetic tunnel junctions can be characterized using the current-in-plane tunneling (CIPT) method, and the key parameters, the resistance-area product (RA) and the tunnel magnetoresistance (TMR), can be determined. The CIPT method...

  3. Using fluorescence lymphangiography to define the ileocolic mesentery: proof of concept for the watershed area using real-time imaging.

    Science.gov (United States)

    Keller, D S; Joshi, H M; Rodriguez-Justo, M; Walsh, D; Coffey, J C; Chand, M

    2017-09-01

    Recent advances in mesenteric science have demonstrated that the mesentery is a continuous structure with a 'watershed' area at the mesenteric apex between the right colon and terminal ileum, where lymphatic flow can proceed either proximally or distally. With this new understanding of the anatomy, functional features are emerging, which can have an impact on surgical management. Fluorescence lymphangiography or lymphoscintigraphy with indocyanine green allows real-time visualization of lymphatic channels, which highlights sentinel lymph nodes and may facilitate identification of the ideal margins for mesenteric lymphadenectomy during bowel resection for colon cancer. By using this novel technology, it is possible to demonstrate a watershed area in the ileocolic region and may facilitate more precise mesenteric dissection. In the present study, we provide proof of concept for the ileocolic watershed area using fluorescence lymphangiography.

  4. Tunneling time, what is its meaning?

    International Nuclear Information System (INIS)

    McDonald, C R; Orlando, G; Vampa, G; Brabec, T

    2015-01-01

    The tunnel time ionization dynamics for bound systems in laser fields are investigated. Numerical analysis for a step function switch-on of the field allows for the tunnel time to be defined as the time it takes the ground state to develop the under-barrier wavefunction components necessary to achieve the static field ionization rate. A relation between the tunnel time and the Keldysh time is established. The definition of the tunnel time is extended to time varying fields and experimental possibilities for measuring the tunnel time are discussed

  5. Determination of coefficient defining leaf area development in different genotypes, plant types and planting densities in peanut (Arachis hypogeae L.).

    Science.gov (United States)

    Halilou, Oumarou; Hissene, Halime Mahamat; Clavijo Michelangeli, José A; Hamidou, Falalou; Sinclair, Thomas R; Soltani, Afshin; Mahamane, Saadou; Vadez, Vincent

    2016-12-01

    Rapid leaf area development may be attractive under a number of cropping conditions to enhance the vigor of crop establishment and allow rapid canopy closure for maximizing light interception and shading of weed competitors. This study was undertaken to determine (1) if parameters describing leaf area development varied among ten peanut ( Arachis hypogeae L.) genotypes grown in field and pot experiments, (2) if these parameters were affected by the planting density, and (3) if these parameters varied between Spanish and Virginia genotypes. Leaf area development was described by two steps: prediction of main stem number of nodes based on phyllochron development and plant leaf area dependent based on main stem node number. There was no genetic variation in the phyllochron measured in the field. However, the phyllochron was much longer for plants grown in pots as compared to the field-grown plants. These results indicated a negative aspect of growing peanut plants in the pots used in this experiment. In contrast to phyllochron, there was no difference in the relationship between plant leaf area and main stem node number between the pot and field experiments. However, there was genetic variation in both the pot and field experiments in the exponential coefficient (PLAPOW) of the power function used to describe leaf area development from node number. This genetic variation was confirmed in another experiment with a larger number of genotypes, although possible G × E interaction for the PLAPOW was found. Sowing density did not affect the power function relating leaf area to main stem node number. There was also no difference in the power function coefficient between Spanish and Virginia genotypes. SSM (Simple Simulation model) reliably predicted leaf canopy development in groundnut. Indeed the leaf area showed a close agreement between predicted and observed values up to 60000 cm 2  m -2 . The slightly higher prediction in India and slightly lower prediction in

  6. Central and peripheral components of writing critically depend on a defined area of the dominant superior parietal gyrus.

    Science.gov (United States)

    Magrassi, Lorenzo; Bongetta, Daniele; Bianchini, Simonetta; Berardesca, Marta; Arienta, Cesare

    2010-07-30

    Classical neuropsychological models of writing separate central (linguistic) processes common to oral spelling, writing and typing from peripheral (motor) processes that are modality specific. Damage to the left superior parietal gyrus, an area of the cortex involved in peripheral processes specific to handwriting, should generate distorted graphemes but not misspelled words, while damage to other areas of the cortex like the frontal lobe should produce alterations in written and oral spelling without distorted graphemes. We describe the clinical and neuropsychological features of a patient with combined agraphia for handwriting and typewriting bearing a small glioblastoma in the left parietal lobe. His agraphia resolved after antiedema therapy and we tested by bipolar cortical stimulation his handwriting abilities during an awake neurosurgical procedure. We found that we could reversibly re-induce the same defects of writing by stimulating during surgery a limited area of the superior parietal gyrus in the same patient and in an independent patient that was never agraphic before the operation. In those patients stimulation caused spelling errors, poorly formed letters and in some cases a complete cessation of writing with minimal or no effects on oral spelling. Our results suggest that stimulating a specific area in the superior parietal gyrus we can generate different patterns of agraphia. Moreover, our findings also suggest that some of the central processes specific for typing and handwriting converge with motor processes at least in the limited portion of the superior parietal gyrus we mapped in our patients. Copyright 2010 Elsevier B.V. All rights reserved.

  7. 16 December 2011 - Israeli Minister of Industry, Trade and Labour S.Simhon visiting ATLAS undeground area, ATLAS visitor centre and LHC tunnel with Senior Physicist G. Mikenberg. ATLAS Collaboration Former Spokesperson is also present.

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    Israeli minister of industry, trade and labour, Shalom Simhon, was welcomed in the ATLAS visitor centre before he toured the ATLAS underground experimental area, where he could see the ATLAS detector. He also had a chance to see the LHC tunnel and the CERN Control Centre.

  8. A Newly Defined Area of the Mouse Anterior Hypothalamus Involved in Septohypothalamic Circuit: Perifornical Area of the Anterior Hypothalamus, PeFAH.

    Science.gov (United States)

    Horii-Hayashi, Noriko; Nishi, Mayumi

    2018-02-27

    Although the hypothalamus is classified into more than 10 compartments, it still contains uncharacterized areas. In this study, we identified a new triangular-shaped area between the paraventricular hypothalamic nucleus (PVN) and the fornix area in the mouse anterior hypothalamus, which is enriched in chondroitin sulfate proteoglycans (CSPGs). We designated this region as the perifornical area of the anterior hypothalamus (PeFAH) based on its anatomical location. As evidenced by Nissl staining, the PeFAH was distinguishable as an area of relatively low density. Immunohistochemical and DNA microarray analyses indicated that PeFAH contains sparsely distributed calretinin-positive neurons and densely clustered enkephalin-positive neurons. Furthermore, the PeFAH was shown to have bidirectional neural connections with the lateral septum. Indeed, we confirmed enkephalinergic projections from PeFAH neurons to the lateral septum, and inversely, calbindin-positive lateral septum neurons as afferents to the PeFAH. Finally, c-Fos expression analysis revealed that the activity of certain PeFAH neuronal populations tended to be increased by psychological stressors, but not that of enkephalinergic neurons. We proposed PeFAH as a new region in the AH.

  9. Defining the urban area for cross national comparison of health indicators: the EURO-URHIS 2 boundary study.

    Science.gov (United States)

    Higgerson, James; Birt, Christopher A; van Ameijden, Erik; Verma, Arpana

    2017-05-01

    Despite much research focusing on the impact of the city condition upon health, there still remains a lack of consensus over what constitutes an urban area (UA). This study was conducted to establish comparable boundaries for the UAs participating in EURO-URHIS 2, and to test whether the sample reflected the heterogeneity of urban living. Key UA contacts ( n = 28) completed a cross-sectional questionnaire, which included where available comparison between Urban Audit city and larger urban zone (LUZ) boundaries and public health administration areas (PHAAs). Additionally, broad health and demographic indicators were sought to test for heterogeneity of the EURO-URHIS 2 sample. Urban Audit city boundaries were found to be suitable for data collection in 100% ( n = 21) of UAs where Urban Audit data were available. The remainder ( n = 7) identified PHAA boundaries akin to the 'city' level. Heterogeneity was observed in the sample for population size and infant mortality rate. Heterogeneity could not be established for male and female life expectancy. This study was able to establish comparable boundaries for EURO-URHIS 2 data collection, with the 'city' area being selected for data collection. The homogeneity of life expectancy indicators was reflective of sub-regional similarities in life expectancy, whilst population estimates and rates of infant mortality indicated the presence of heterogeneity within the sample. Future work would trial these methods with a larger number of indicators and for a larger number of UAs. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

  10. The prevalence of ALK rearrangement in pulmonary adenocarcinomas in an unselected Caucasian population from a defined catchment area

    DEFF Research Database (Denmark)

    Skov, Birgit G; Clementsen, Paul; Larsen, Klaus R

    2017-01-01

    . METHODS AND RESULTS: All patients diagnosed in the population of the greater Copenhagen area were included, irrespective of gender, age, smoking habits, stage or type of available diagnostic material. Tumours were stained with immunohistochemistry (clone 5A4). Immunohistochemistry-positive tumours were......AIMS: To assess the prevalence of EML4-ALK rearrangement gene measured by immunohistochemistry in an unselected population-based consecutive cohort of patients with adenocarcinoma of the lung (ACL), and the correlation with smoking history, thyroid transcription factor 1 (TTF1), gender and age...

  11. Presynaptic Regulation of Leptin in a Defined Lateral Hypothalamus-Ventral Tegmental Area Neurocircuitry Depends on Energy State.

    Science.gov (United States)

    Liu, Jing-Jing; Bello, Nicholas T; Pang, Zhiping P

    2017-12-06

    Synaptic transmission controls brain activity and behaviors, including food intake. Leptin, an adipocyte-derived hormone, acts on neurons located in the lateral hypothalamic area (LHA) to maintain energy homeostasis and regulate food intake behavior. The specific synaptic mechanisms, cell types, and neural projections mediating this effect remain unclear. In male mice, using pathway-specific retrograde tracing, whole-cell patch-clamp recordings and post hoc cell type identification, we found that leptin reduces excitatory synaptic strength onto both melanin-concentrating hormone- and orexin-expressing neurons projecting from the LHA to the ventral tegmental area (VTA), which may affect dopamine signaling and motivation for feeding. A presynaptic mechanism mediated by distinct intracellular signaling mechanisms may account for this regulation by leptin. The regulatory effects of leptin depend on intact leptin receptor signaling. Interestingly, the synaptic regulatory function of leptin in the LHA-to-VTA neuronal pathway is highly sensitive to energy states: both energy deficiency (acute fasting) and excessive energy storage (high-fat diet-induced obesity) blunt the effect of leptin. These data revealed that leptin may regulate synaptic transmission in the LHA-to-VTA neurocircuitry in an inverted "U-shape" fashion dependent on plasma glucose levels and related to metabolic states. SIGNIFICANCE STATEMENT The lateral hypothalamic area (LHA) to ventral tegmental area (VTA) projection is an important neural pathway involved in balancing whole-body energy states and reward. We found that the excitatory synaptic inputs to both orexin- and melanin-concentrating hormone expressing LHA neurons projecting to the VTA were suppressed by leptin, a peptide hormone derived from adipocytes that signals peripheral energy status to the brain. Interestingly, energy states seem to affect how leptin regulates synaptic transmission since both the depletion of energy induced by acute food

  12. Tunneling Flight Time, Chemistry, and Special Relativity.

    Science.gov (United States)

    Petersen, Jakob; Pollak, Eli

    2017-09-07

    Attosecond ionization experiments have not resolved the question "What is the tunneling time?". Different definitions of tunneling time lead to different results. Second, a zero tunneling time for a material particle suggests that the nonrelativistic theory includes speeds greater than the speed of light. Chemical reactions, occurring via tunneling, should then not be considered in terms of a nonrelativistic quantum theory calling into question quantum dynamics computations on tunneling reactions. To answer these questions, we define a new experimentally measurable paradigm, the tunneling flight time, and show that it vanishes for scattering through an Eckart or a square barrier, irrespective of barrier length or height, generalizing the Hartman effect. We explain why this result does not lead to experimental measurement of speeds greater than the speed of light. We show that this tunneling is an incoherent process by comparing a classical Wigner theory with exact quantum mechanical computations.

  13. LAND SUITABILITY AND DYNAMIC SYSTEM MODELLING TO DEFINE PRIORITY AREAS OF SOYBEAN PLANTATION IN PADDY FIELDS IN KARAWANG, WEST JAVA

    Directory of Open Access Journals (Sweden)

    Widiatmaka

    2014-10-01

    Full Text Available One of the agricultural public commodities in Indonesia which still cannot fulfill its domestic consumption needs is soybean. The objectives of the research, which was conducted in Karawang Regency, West Java, Indonesia, were to: (i identify the suitable area for soybean plantations in paddy fields, (ii assess the development of soybeans in land use and socio-economic context, and (iii plan the spatially soybean plantation. A soil survey and land evaluation for soybean was completed. IKONOS imagery was applied to delineate paddy fields while a dynamic system modelling was developed using Powersim 8.0 software. The results of the research showed that the suitability class for soybean plantation in the paddy fields of Karawang Regency ranges from unsuitable (N to suitable (S2, with limiting factors being temperature, fertility, nutrients retention, slope, erosion, rooting media and toxicity. Very limited arable land has been used so far for soybeans plantations due to low economic returns. The model predicts that, should the development of soybean continues in its business as usual path, a deficit of soybean will occur in 2030. The model provides alternative scenarios to reduce the deficit. Prioritization was done spatially using the suitable land gradually, corresponding to the government budget availability.

  14. Pathogen-Specific Epitopes as Epidemiological Tools for Defining the Magnitude of Mycobacterium leprae Transmission in Areas Endemic for Leprosy

    Science.gov (United States)

    Spencer, John S.; Hacker, Mariana A. V. B.; Costa, Luciana S.; Carvalho, Fernanda M.; Geluk, Annemieke; van der Ploeg-van Schip, Jolien J.; Pontes, Maria A. A.; Gonçalves, Heitor S.; de Morais, Janvier P.; Bandeira, Tereza J. P. G.; Pessolani, Maria C. V.; Brennan, Patrick J.; Pereira, Geraldo M. B.

    2012-01-01

    During recent years, comparative genomic analysis has allowed the identification of Mycobacterium leprae-specific genes with potential application for the diagnosis of leprosy. In a previous study, 58 synthetic peptides derived from these sequences were tested for their ability to induce production of IFN-γ in PBMC from endemic controls (EC) with unknown exposure to M. leprae, household contacts of leprosy patients and patients, indicating the potential of these synthetic peptides for the diagnosis of sub- or preclinical forms of leprosy. In the present study, the patterns of IFN-γ release of the individuals exposed or non-exposed to M. leprae were compared using an Artificial Neural Network algorithm, and the most promising M. leprae peptides for the identification of exposed people were selected. This subset of M. leprae-specific peptides allowed the differentiation of groups of individuals from sites hyperendemic for leprosy versus those from areas with lower level detection rates. A progressive reduction in the IFN-γ levels in response to the peptides was seen when contacts of multibacillary (MB) patients were compared to other less exposed groups, suggesting a down modulation of IFN-γ production with an increase in bacillary load or exposure to M. leprae. The data generated indicate that an IFN-γ assay based on these peptides applied individually or as a pool can be used as a new tool for predicting the magnitude of M. leprae transmission in a given population. PMID:22545169

  15. Urban Growth Areas, Priority Funding Area (PFA) - Vector Database. PFAs are geographic growth areas defined under State law and designated by local jurisdictions to provide a map for targeting State investment in infrastructure., Published in 1998, 1:24000 (1in=2000ft) scale, Maryland Department of Planning.

    Data.gov (United States)

    NSGIC State | GIS Inventory — Urban Growth Areas dataset current as of 1998. Priority Funding Area (PFA) - Vector Database. PFAs are geographic growth areas defined under State law and designated...

  16. A GIS-based methodology to quantitatively define an Adjacent Protected Area in a shallow karst cavity: the case of Altamira cave.

    Science.gov (United States)

    Elez, J; Cuezva, S; Fernandez-Cortes, A; Garcia-Anton, E; Benavente, D; Cañaveras, J C; Sanchez-Moral, S

    2013-03-30

    Different types of land use are usually present in the areas adjacent to many shallow karst cavities. Over time, the increasing amount of potentially harmful matter and energy, of mainly anthropic origin or influence, that reaches the interior of a shallow karst cavity can modify the hypogeal ecosystem and increase the risk of damage to the Palaeolithic rock art often preserved within the cavity. This study proposes a new Protected Area status based on the geological processes that control these matter and energy fluxes into the Altamira cave karst system. Analysis of the geological characteristics of the shallow karst system shows that direct and lateral infiltration, internal water circulation, ventilation, gas exchange and transmission of vibrations are the processes that control these matter and energy fluxes into the cave. This study applies a comprehensive methodological approach based on Geographic Information Systems (GIS) to establish the area of influence of each transfer process. The stratigraphic and structural characteristics of the interior of the cave were determined using 3D Laser Scanning topography combined with classical field work, data gathering, cartography and a porosity-permeability analysis of host rock samples. As a result, it was possible to determine the hydrogeological behavior of the cave. In addition, by mapping and modeling the surface parameters it was possible to identify the main features restricting hydrological behavior and hence direct and lateral infiltration into the cave. These surface parameters included the shape of the drainage network and a geomorphological and structural characterization via digital terrain models. Geological and geomorphological maps and models integrated into the GIS environment defined the areas involved in gas exchange and ventilation processes. Likewise, areas that could potentially transmit vibrations directly into the cave were identified. This study shows that it is possible to define a

  17. Defining the most probable location of the parahippocampal place area using cortex-based alignment and cross-validation.

    Science.gov (United States)

    Weiner, Kevin S; Barnett, Michael A; Witthoft, Nathan; Golarai, Golijeh; Stigliani, Anthony; Kay, Kendrick N; Gomez, Jesse; Natu, Vaidehi S; Amunts, Katrin; Zilles, Karl; Grill-Spector, Kalanit

    2018-04-15

    The parahippocampal place area (PPA) is a widely studied high-level visual region in the human brain involved in place and scene processing. The goal of the present study was to identify the most probable location of place-selective voxels in medial ventral temporal cortex. To achieve this goal, we first used cortex-based alignment (CBA) to create a probabilistic place-selective region of interest (ROI) from one group of 12 participants. We then tested how well this ROI could predict place selectivity in each hemisphere within a new group of 12 participants. Our results reveal that a probabilistic ROI (pROI) generated from one group of 12 participants accurately predicts the location and functional selectivity in individual brains from a new group of 12 participants, despite between subject variability in the exact location of place-selective voxels relative to the folding of parahippocampal cortex. Additionally, the prediction accuracy of our pROI is significantly higher than that achieved by volume-based Talairach alignment. Comparing the location of the pROI of the PPA relative to published data from over 500 participants, including data from the Human Connectome Project, shows a striking convergence of the predicted location of the PPA and the cortical location of voxels exhibiting the highest place selectivity across studies using various methods and stimuli. Specifically, the most predictive anatomical location of voxels exhibiting the highest place selectivity in medial ventral temporal cortex is the junction of the collateral and anterior lingual sulci. Methodologically, we make this pROI freely available (vpnl.stanford.edu/PlaceSelectivity), which provides a means to accurately identify a functional region from anatomical MRI data when fMRI data are not available (for example, in patient populations). Theoretically, we consider different anatomical and functional factors that may contribute to the consistent anatomical location of place selectivity

  18. Estimating the incidence of connective tissue diseases and vasculitides in a defined population in Northern Savo area in 2010.

    Science.gov (United States)

    Elfving, P; Marjoniemi, O; Niinisalo, H; Kononoff, A; Arstila, L; Savolainen, E; Rutanen, J; Kaipiainen-Seppänen, O

    2016-07-01

    Objective of the study was to evaluate the annual incidence and distribution of autoimmune connective tissue diseases and vasculitides during 2010. All units practicing rheumatology in the Northern Savo area, Finland, participated in the study by collecting data on newly diagnosed adult patients with autoimmune connective tissue disease or vasculitis over 1-year period. Seventy-two cases with autoimmune connective tissue disease were identified. The annual incidence rates were as follows: systemic lupus erythematosus 3.4/100,000 (95 % CI 1.4-7.0), idiopathic inflammatory myopathies 1.9 (0.5-5.0), systemic sclerosis 4.4 (2.0-8.3), mixed connective tissue disease 1.0 (0.1-3.5), Sjögren's syndrome 10.7 (6.7-16.1) and undifferentiated connective tissue disease 13.6 (9.0-19.6). The annual incidence rates among vasculitis category were as follows: antineutrophil cytoplasmic antibody-associated vasculitis 1.5/100,000 (95 % CI 0.3-4.3), central nervous system vasculitis 0.5 (0-2.7) and Henoch-Schönlein purpura 1.5 (0.3-4.3). The annual incidence of giant cell arteritis in the age group of 50 years or older was 7.5/100,000 (95 % CI 3.2-14.8). The longest delay from symptom onset to diagnosis occurred in systemic sclerosis. The incidences of autoimmune connective tissue diseases and vasculitides were comparable with those in published literature. The present study showed female predominance in all connective tissue diseases, excluding idiopathic inflammatory muscle diseases and mean age at onset of disease around 50 years of age. Despite improved diagnostic tools, diagnostic delay is long especially among patients with systemic sclerosis.

  19. Recognition tunneling

    Czech Academy of Sciences Publication Activity Database

    Lindsay, S.; He, J.; Sankey, O.; Hapala, Prokop; Jelínek, Pavel; Zhang, P.; Chang, S.; Huang, S.

    2010-01-01

    Roč. 21, č. 26 (2010), 262001/1-262001/12 ISSN 0957-4484 R&D Projects: GA ČR GA202/09/0545 Institutional research plan: CEZ:AV0Z10100521 Keywords : STM * tunneling current * molecular electronics * DFT calculations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.644, year: 2010

  20. Use of geoprocessing to define malaria risk areas and evaluation of the vectorial importance of anopheline mosquitoes (Diptera: Culicidae) in Espírito Santo, Brazil.

    Science.gov (United States)

    Meneguzzi, Viviane Coutinho; Santos, Claudiney Biral dos; Pinto, Israel de Souza; Feitoza, Leandro Roberto; Feitoza, Hideko Nagatani; Falqueto, Aloísio

    2009-07-01

    In Brazil, introduced malaria occurs from the flat to the sloping hot areas, predominantly outside the Amazon Region, where endemic malaria has occurred in the past. This is a consequence of human migrations to other Brazilian states, including the state of Espírito Santo (ES). The objective of this study was to use geoprocessing to define the areas at risk of introduced malaria transmission and evaluate the vectorial importance of species of anophelines in ES. Anophelines were sampled from 1997-2005 in 297 rural localities identified or not identified as foci of malaria during the last 20 years. The geoclimatic variables temperature, relief and marine influence were obtained from a database of the ES Natural Units. The 14,663 anophelines captured belonged to 22 species. A significant association was found between the occurrence of malaria foci and the presence of hot, low-lying areas or gently undulating to undulating relief. The occurrence of the disease was associated with the presence of Anopheles darlingi and Anopheles aquasalis. Geoprocessing was determined to be a useful tool for defining areas at risk for malaria and vectors in ES.

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

    Data.gov (United States)

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

  2. Defining Persistent Hotspots: Areas That Fail to Decrease Meaningfully in Prevalence after Multiple Years of Mass Drug Administration with Praziquantel for Control of Schistosomiasis.

    Science.gov (United States)

    Kittur, Nupur; Binder, Sue; Campbell, Carl H; King, Charles H; Kinung'hi, Safari; Olsen, Annette; Magnussen, Pascal; Colley, Daniel G

    2017-12-01

    Preventive chemotherapy with praziquantel for schistosomiasis morbidity control is commonly done by mass drug administration (MDA). MDA regimen is usually based on prevalence in a given area, and effectiveness is evaluated by decreases in prevalence and/or intensity of infection after several years of implementation. Multiple studies and programs now find that even within well-implemented, multiyear, annual MDA programs there often remain locations that do not decline in prevalence and/or intensity to expected levels. We term such locations "persistent hotspots." To study and address persistent hotspots, investigators and neglected tropical disease (NTD) program managers need to define them based on changes in prevalence and/or intensity. But how should the data be analyzed to define a persistent hotspot? We have analyzed a dataset from an operational research study in western Tanzania after three annual MDAs using four different approaches to define persistent hotspots. The four approaches are 1) absolute percent change in prevalence; 2) percent change in prevalence; 3) change in World Health Organization guideline categories; 4) change (absolute or percent) in both prevalence and intensity. We compare and contrast the outcomes of these analyses. Our intent is to show how the same dataset yields different numbers of persistent hotspots depending on the approach used to define them. We suggest that investigators and NTD program managers use the approach most suited for their study or program, but whichever approach is used, it should be clearly stated so that comparisons can be made within and between studies and programs.

  3. Tunnel - history of

    International Nuclear Information System (INIS)

    1998-11-01

    This book introduces history of tunnel in ancient times, the middle ages and modern times, survey of tunnel and classification of bedrock like environment survey of position, survey of the ground, design of tunnel on basic thing of the design, and design of tunnel of bedrock, analysis of stability of tunnel and application of the data, construction of tunnel like lattice girder and steel fiber reinforced shot crete, and maintenance control and repair of tunnel.

  4. Road tunnels safety according to European legislation

    Directory of Open Access Journals (Sweden)

    Fedor KÁLLAY

    2008-01-01

    Full Text Available The article deals with safety of European road tunnels in accordance with actual European legislation. Standards and recommendations of European Commission, PIARC and other professional bodies of the European Union define minimal technological requirements for equipment and operation of the tunnels in scope of Trans-European Road Network.

  5. Tunneling path toward spintronics

    International Nuclear Information System (INIS)

    Miao Guoxing; Moodera, Jagadeesh S; Muenzenberg, Markus

    2011-01-01

    The phenomenon of quantum tunneling, which was discovered almost a century ago, has led to many subsequent discoveries. One such discovery, spin polarized tunneling, was made 40 years ago by Robert Meservey and Paul Tedrow (Tedrow and Meservey 1971 Phys. Rev. Lett. 26 192), and it has resulted in many fundamental observations and opened up an entirely new field of study. Until the mid-1990s, this field developed at a steady, low rate, after which a huge increase in activity suddenly occurred as a result of the unraveling of successful spin tunneling between two ferromagnets. In the past 15 years, several thousands of papers related to spin polarized tunneling and transport have been published, making this topic one of the hottest areas in condensed matter physics from both fundamental science and applications viewpoints. Many review papers and book chapters have been written in the past decade on this subject. This paper is not exhaustive by any means; rather, the emphases are on recent progress, technological developments and informing the reader about the current direction in which this topic is moving.

  6. Model Penilaian Transaksi Pihak Berelasi Yang Terindikasi Tunneling: Bukti Empiris Pada Transaksi Pihak Berelasi Di Indonesia

    OpenAIRE

    Sari, Ratna Chandra

    2012-01-01

    This study focuses on the expropriation of non-controlling shareholders through tunneling activity. Current study in tunneling still found obstacles in measurement because it is difficult to prove, although tunneling activity going on in business practices. The objective of this is to develop tunneling valuation model. This study defines the tunneling as related party transactions that are used to tunnel out of public companies' resource for the benefit of the controlling shareholder. Tunneli...

  7. Nanoimprint-defined, large-area meta-surfaces for unidirectional optical transmission with superior extinction in the visible-to-infrared range.

    Science.gov (United States)

    Yao, Yuhan; Liu, He; Wang, Yifei; Li, Yuanrui; Song, Boxiang; Wang, Richard P; Povinelli, Michelle L; Wu, Wei

    2016-07-11

    Optical devices with asymmetric transmission have important applications in optical systems, but optical isolators with the modal asymmetry can only be built using magneto-optical or nonlinear materials, as dictated by the Lorentz reciprocity theorem. However, optical devices with the power asymmetry can be achieved by linear materials such as metals and dielectrics. In this paper, we report a large-area, nanoimprint-defined meta-surface (stacked subwavelength gratings) with high-contrast asymmetric transmittance in the visible-to-infrared wavelength range for TM-polarized light. The physical origin of asymmetric transmission through the meta-surface is studied by analyzing the scattering matrix.

  8. Tunnel blasting - recent developments

    Energy Technology Data Exchange (ETDEWEB)

    White, T.E.

    1999-05-01

    While tunnelling machines are more efficient than previously, there are still areas where blasting is a more efficient method of advance. Drilling and design methods are increasingly sophisticated, as is choice of explosive. Explosive deployment must be carefully calculated so as to avoid desensitisation. Nitroglycerine may be used as slurries; bulk mixing on site of ANFO is also practised in mining in the UK. Electric detonators, Nonel tubes, and electronic detonators are also increasingly employed.

  9. Klein tunneling phenomenon with pair creation process

    Science.gov (United States)

    Wu, G. Z.; Zhou, C. T.; Fu, L. B.

    2018-01-01

    In this paper, we study the Klein tunneling phenomenon with electron-positron pair creation process. Pairs can be created from the vacuum by a supercritical single-well potential (for electrons). In the time region, the time-dependent growth pattern of the created pairs can be characterized by four distinct regimes which can be considered as four different statuses of the single well. We find that if positrons penetrate the single well by Klein tunneling in different statuses, the total number of the tunneling positrons will be different. If Klein tunneling begins at the initial stage of the first status i.e. when the sing well is empty, the tunneling process and the total number of tunneling positrons are similar to the traditional Klein tunneling case without considering the pair creation process. As the tunneling begins later, the total tunneling positron number increases. The number will finally settle to an asymptotic value when the tunneling begins later than the settling-down time t s of the single well which has been defined in this paper.

  10. Carpal Tunnel Syndrome

    Science.gov (United States)

    ... a passing cramp? It could be carpal tunnel syndrome. The carpal tunnel is a narrow passageway of ... three times more likely to have carpal tunnel syndrome than men. Early diagnosis and treatment are important ...

  11. Urban Growth Areas, This Layer represents the current Urbanized Area for Atlanta as defined by the U.S. Census Bureau. An Urbanized Area is a concept used by the U.S. Census Bureau to measure the population, land area and population density of a built-up or continuously deve, Published in 2000, 1:100000 (1in=8333ft) scale, Atlanta Regional Commission.

    Data.gov (United States)

    NSGIC Regional | GIS Inventory — Urban Growth Areas dataset current as of 2000. This Layer represents the current Urbanized Area for Atlanta as defined by the U.S. Census Bureau. An Urbanized Area...

  12. TunnelVision: LHC Tunnel Photogrammetry System for Structural Monitoring

    CERN Document Server

    Fallas, William

    2014-01-01

    In this document an algorithm to detect deformations in the LHC Tunnel of CERN is presented. It is based on two images, one represents the ideal state of the tunnel and the other one the actual state. To find the differences between both, the algorithm is divided in three steps. First, an image enhancement is applied to make easier the detection. Second, two different approaches to reduce noise are applied to one or both images. And third, it is defined a group of characteristics about the type of deformation desired to detect. Finally, the conclusions show the effectiveness of the algorithm in the experimental results.

  13. Tunneling technologies for the collider ring tunnels

    International Nuclear Information System (INIS)

    Frobenius, P.

    1989-01-01

    The Texas site chosen for the Superconducting Super Collider has been studied, and it has been determined that proven, conventional technology and accepted engineering practice are suitable for constructing the collider tunnels. The Texas National Research Laboratory Commission report recommended that two types of tunneling machines be used for construction of the tunnels: a conventional hard rock tunnel boring machine (TBM) for the Austin chalk and a double shielded, rotary TBM for the Taylor marl. Since the tunneling machines usually set the pace for the project, efficient planning, operation, and coordination of the tunneling system components will be critical to the schedule and cost of the project. During design, tunneling rate prediction should be refined by focusing on the development of an effective tunneling system and evaluating its capacity to meet or exceed the required schedules. 8 refs., 13 figs

  14. Tunneling through landsliding zone; Jisuberi chitainai no tunnel seko

    Energy Technology Data Exchange (ETDEWEB)

    Konbu, A; Hatabu, K; Kano, T [Tekken Corp., Tokyo (Japan)

    1994-08-01

    At the new tunnel construction site of the Shirakata tunnel on the Obama line in Yamaguchi Prefecture, a landsliding occurred at about 60 meters to the upper portion obliquely to the right hand side of the shaft when the excavation progressed to about 10 meters from the starting side. The landslide caused displacement at the shaft opening and change in the supports. As a result of the re-investigation, it was confirmed that the slide face went through the tunnel cross section. The measures taken were removal of the upper soil and an adoption of the all ground fastening (AGF) method (injection type long tip fastening method) as an auxiliary construction to stop loosening of the natural ground associated with the tunnel excavation. The result was a completion of tunneling the landsliding zone without a problem. This paper reports the AGF method adopted in the above construction, together with the construction works and natural ground conditions. The AGF method is about the same as the pipe roof method with regard to the natural ground accepting mechanism and the materials used. The difference is building an improved body in a limited area in the natural ground around the steel pipes by injecting the fixing material. The use of this method caused no problems in subsidence and displacement in the surrounding ground, and completed the tunneling construction without an unusual event. 1 ref., 7 figs., 2 tabs.

  15. Do rivers really obey power-laws? Using continuous high resolution measurements to define bankfull channel and evaluate downstream hydraulic-scaling over large changes in drainage area

    Science.gov (United States)

    Scher, C.; Tennant, C.; Larsen, L.; Bellugi, D. G.

    2016-12-01

    Advances in remote-sensing technology allow for cost-effective, accurate, high-resolution mapping of river-channel topography and shallow aquatic bathymetry over large spatial scales. A combination of near-infrared and green spectra airborne laser swath mapping was used to map river channel bathymetry and watershed geometry over 90+ river-kilometers (75-1175 km2) of the Greys River in Wyoming. The day of flight wetted channel was identified from green LiDAR returns, and more than 1800 valley-bottom cross-sections were extracted at regular 50-m intervals. The bankfull channel geometry was identified using a "watershed-based" algorithm that incrementally filled local minima to a "spill" point, thereby constraining areas of local convergence and delineating all the potential channels along the cross-section for each distinct "spill stage." Multiple potential channels in alluvial floodplains and lack of clearly defined channel banks in bedrock reaches challenge identification of the bankfull channel based on topology alone. Here we combine a variety of topological measures, geometrical considerations, and stage levels to define a stage-dependent bankfull channel geometry, and compare the results with day of flight wetted channel data. Initial results suggest that channel hydraulic geometry and basin hydrology power-law scaling may not accurately capture downstream channel adjustments for rivers draining complex mountain topography.

  16. Improved multidimensional semiclassical tunneling theory.

    Science.gov (United States)

    Wagner, Albert F

    2013-12-12

    We show that the analytic multidimensional semiclassical tunneling formula of Miller et al. [Miller, W. H.; Hernandez, R.; Handy, N. C.; Jayatilaka, D.; Willets, A. Chem. Phys. Lett. 1990, 172, 62] is qualitatively incorrect for deep tunneling at energies well below the top of the barrier. The origin of this deficiency is that the formula uses an effective barrier weakly related to the true energetics but correctly adjusted to reproduce the harmonic description and anharmonic corrections of the reaction path at the saddle point as determined by second order vibrational perturbation theory. We present an analytic improved semiclassical formula that correctly includes energetic information and allows a qualitatively correct representation of deep tunneling. This is done by constructing a three segment composite Eckart potential that is continuous everywhere in both value and derivative. This composite potential has an analytic barrier penetration integral from which the semiclassical action can be derived and then used to define the semiclassical tunneling probability. The middle segment of the composite potential by itself is superior to the original formula of Miller et al. because it incorporates the asymmetry of the reaction barrier produced by the known reaction exoergicity. Comparison of the semiclassical and exact quantum tunneling probability for the pure Eckart potential suggests a simple threshold multiplicative factor to the improved formula to account for quantum effects very near threshold not represented by semiclassical theory. The deep tunneling limitations of the original formula are echoed in semiclassical high-energy descriptions of bound vibrational states perpendicular to the reaction path at the saddle point. However, typically ab initio energetic information is not available to correct it. The Supporting Information contains a Fortran code, test input, and test output that implements the improved semiclassical tunneling formula.

  17. 28th January 2011-Vice-President Max Planck Society-Prof. Martin Stratmann-Germany-visiting the ATLAS experimental area and the LHC Tunnel at CERN

    CERN Multimedia

    Jean-Claude Gadmer

    2011-01-01

    Photo 1:ATLAS visitor Center with P. Jenni, ATLAS Collaboration former spokesperson Photo 2-10:visiting the ATLAS cavern Photo 10:D. Hoppe,P. Jenni,M. Stratmann,S. Bethke,S. Braun,D. Klammer Photo 11-15:visiting the LHC tunnel Photo 16-18:Signature of the Guest Book with S. Lettow,Director for Administration and General Infrastructure

  18. Define Project

    DEFF Research Database (Denmark)

    Munk-Madsen, Andreas

    2005-01-01

    "Project" is a key concept in IS management. The word is frequently used in textbooks and standards. Yet we seldom find a precise definition of the concept. This paper discusses how to define the concept of a project. The proposed definition covers both heavily formalized projects and informally...... organized, agile projects. Based on the proposed definition popular existing definitions are discussed....

  19. "Dermatitis" defined.

    Science.gov (United States)

    Smith, Suzanne M; Nedorost, Susan T

    2010-01-01

    The term "dermatitis" can be defined narrowly or broadly, clinically or histologically. A common and costly condition, dermatitis is underresourced compared to other chronic skin conditions. The lack of a collectively understood definition of dermatitis and its subcategories could be the primary barrier. To investigate how dermatologists define the term "dermatitis" and determine if a consensus on the definition of this term and other related terms exists. A seven-question survey of dermatologists nationwide was conducted. Of respondents (n  =  122), half consider dermatitis to be any inflammation of the skin. Nearly half (47.5%) use the term interchangeably with "eczema." Virtually all (> 96%) endorse the subcategory "atopic" under the terms "dermatitis" and "eczema," but the subcategories "contact," "drug hypersensitivity," and "occupational" are more highly endorsed under the term "dermatitis" than under the term "eczema." Over half (55.7%) personally consider "dermatitis" to have a broad meaning, and even more (62.3%) believe that dermatologists as a whole define the term broadly. There is a lack of consensus among experts in defining dermatitis, eczema, and their related subcategories.

  20. Air pollution knows no boundaries: defining air catchment areas and making sense of physical and political boundaries in air quality management

    CSIR Research Space (South Africa)

    Scott, G

    2005-10-01

    Full Text Available Topics under discussion: Scales of transport and turbulence in the atmosphere; Examples of global, regional and local scale transports – concepts of an “air catchment”; Defining air quality management zones - international practice; Defining air...

  1. Clinical, bacteriological, and histopathological characteristics of newly detected children with leprosy: A population based study in a defined rural and urban area of Maharashtra, Western India

    Directory of Open Access Journals (Sweden)

    Vanaja P Shetty

    2013-01-01

    Full Text Available Background: Leprosy has been a major public-health problem in many developing countries for centuries. According to the National Leprosy Elimination Programme report of March 2012, there were a total of about 0.13 million cases of leprosy in India, 9.7% of which were children. Numerous studies have investigated child leprosy amongst reported cases however, studies pertaining to proportion and characteristics of undetected childhood cases in the community are very few. Aim: To examine the clinical, bacteriological, and histopathological characteristics of newly detected child leprosy cases in the community. Methods: The population survey conducted from June to September 2007 and the defined rural areas, which included five primary health centers of Panvel Taluka, in Raigad district and urban areas, which included M-east ward of the municipal corporation of greater Mumbai of western Maharashtra, India. Results: House-to-house survey yielded 32 and 37 so far, undetected child cases of leprosy in the rural and urban region, and the prevalence rate was 10.5 and 1.5 per 10,000, respectively. The age of child leprosy cases detected, ranged from 3 to 14 years with a mean of 10.06 ± 3.35 years in the rural and 9.97 ± 3.12 years in the urban area. Most of the cases were paucibacillary (62%. A large proportion of children (49% had single skin lesion (SSL. Of the 19 SSL cases examined histopathologically, 15 (99% showed features of borderline tuberculoid, 1 (5% borderline lepromatous and 3 (16% had indeterminate type of leprosy. Tuberculoid leprosy was not seen in any, indicating less likelihood of self-healing. Overall, three cases had deformity (grade 1 = 1 and grade 2 = 2 and 31% of multibacillary cases were smear positive. Conclusion: The clinical, bacteriological, and histopathological characteristics of newly detected child cases in the community evidently indicate the grave nature of the problem of undetected child leprosy, recent active

  2. Defining chaos.

    Science.gov (United States)

    Hunt, Brian R; Ott, Edward

    2015-09-01

    In this paper, we propose, discuss, and illustrate a computationally feasible definition of chaos which can be applied very generally to situations that are commonly encountered, including attractors, repellers, and non-periodically forced systems. This definition is based on an entropy-like quantity, which we call "expansion entropy," and we define chaos as occurring when this quantity is positive. We relate and compare expansion entropy to the well-known concept of topological entropy to which it is equivalent under appropriate conditions. We also present example illustrations, discuss computational implementations, and point out issues arising from attempts at giving definitions of chaos that are not entropy-based.

  3. Defining Cyberbullying.

    Science.gov (United States)

    Englander, Elizabeth; Donnerstein, Edward; Kowalski, Robin; Lin, Carolyn A; Parti, Katalin

    2017-11-01

    Is cyberbullying essentially the same as bullying, or is it a qualitatively different activity? The lack of a consensual, nuanced definition has limited the field's ability to examine these issues. Evidence suggests that being a perpetrator of one is related to being a perpetrator of the other; furthermore, strong relationships can also be noted between being a victim of either type of attack. It also seems that both types of social cruelty have a psychological impact, although the effects of being cyberbullied may be worse than those of being bullied in a traditional sense (evidence here is by no means definitive). A complicating factor is that the 3 characteristics that define bullying (intent, repetition, and power imbalance) do not always translate well into digital behaviors. Qualities specific to digital environments often render cyberbullying and bullying different in circumstances, motivations, and outcomes. To make significant progress in addressing cyberbullying, certain key research questions need to be addressed. These are as follows: How can we define, distinguish between, and understand the nature of cyberbullying and other forms of digital conflict and cruelty, including online harassment and sexual harassment? Once we have a functional taxonomy of the different types of digital cruelty, what are the short- and long-term effects of exposure to or participation in these social behaviors? What are the idiosyncratic characteristics of digital communication that users can be taught? Finally, how can we apply this information to develop and evaluate effective prevention programs? Copyright © 2017 by the American Academy of Pediatrics.

  4. Superconducting tunnel-junction refrigerator

    International Nuclear Information System (INIS)

    Melton, R.G.; Paterson, J.L.; Kaplan, S.B.

    1980-01-01

    The dc current through an S 1 -S 2 tunnel junction, with Δ 2 greater than Δ 1 , when biased with eV 1 +Δ 2 , will lower the energy in S 1 . This energy reduction will be shared by the phonons and electrons. This device is shown to be analogous to a thermoelectric refrigerator with an effective Peltier coefficient π* approx. Δ 1 /e. Tunneling calculations yield the cooling power P/sub c/, the electrical power P/sub e/ supplied by the bias supply, and the cooling efficiency eta=P/sub c//P/sub e/. The maximum cooling power is obtained for eV= +- (Δ 2 -Δ 1 ) and t 1 =T 1 /T/sub c/1 approx. 0.9. Estimates are made of the temperature difference T 2 -T 1 achievable in Al-Pb and Sn-Pb junctions with an Al 2 O 3 tunneling barrier. The performance of this device is shown to yield a maximum cooling efficiency eta approx. = Δ 1 /(Δ 2 -Δ 1 ) which can be compared with that available in an ideal Carnot refrigerator of eta=T 1 /(T 2 -T 1 ). The development of a useful tunnel-junction refrigerator requires a tunneling barrier with an effective thermal conductance per unit area several orders of magnitude less than that provided by the A1 2 O 3 barrier in the Al-Pb and Sn-Pb systems

  5. Enhanced MRI in carpal tunnel syndrome

    International Nuclear Information System (INIS)

    Hayakawa, Katsuhiko; Nakane, Takashi; Kobayashi, Shigeru; Asai, Takahiro; Wada, Kunio; Yoshizawa, Hidezo

    1998-01-01

    In this study, we performed contrast-enhanced MRI in patients with idiopathic carpal tunnel syndrome and examined the morphologic change in the carpal tunnel. In the transverse section of the opening of carpal tunnel where scaphoid and pisiform bones are figured out, we measured and examined 4 items, viz. the soft carpal tunnel volume, flat rate of median nerve, position of median nerve and thickness of palmer ligaments composing the base of carpal tunnel, with an image analyzer attached to the MRI apparatus. Whereas the average carpal tunnel volume in 12 hands of normal controls was 166.8 mm 2 , that in 74 hands of carpal tunnel syndrome was 207.2 mm 2 , a significant increase compared with the normal controls. The flat rate of median nerve was 46% in the controls, but that was 37.5% in the carpal tunnel syndrome, a significant flattening was noted. We connected the peaks of the scaphoid node and pisiform bone with a line and named it standard line. When we observed the position of median nerve in the carpal tunnel, the nerve in 9 of 12 hands, 75%, lay below the standard line in the controls, but the nerve in 65 of 74 hands, 87.8%, lay above the standard line in the carpal tunnel syndrome, clearly showing that the median nerve had shifted to the palmar side. Regarding these morphologic changes of the carpal tunnel, the internal pressure of the carpal tunnel is considered to be raised with swelling of the soft tissues mainly composing the inside of carpal tunnel, thus the area of cross section of carpal tunnel to be increased, the median nerve to be shifted to the palmar side and the median nerve to be compressed by the transverse carpal ligament at that time. Although we can observe these morphological changes readily in MRI images, these images show only the results of carpal tunnel syndrome after all, and do not specify the direct causes. However, we believe that these facts are important factors in the manifestation of idiopathic carpal tunnel syndrome. (author)

  6. Tunneling time, exit time and exit momentum in strong field tunnel ionization

    International Nuclear Information System (INIS)

    Teeny, Nicolas

    2016-01-01

    Tunnel ionization belongs to the fundamental processes of atomic physics. It is still an open question when does the electron tunnel ionize and how long is the duration of tunneling. In this work we solve the time-dependent Schroedinger equation in one and two dimensions and use ab initio quantum calculations in order to answer these questions. Additionally, we determine the exit momentum of the tunnel ionized electron from first principles. We find out results that are different from the assumptions of the commonly employed two-step model, which assumes that the electron ionizes at the instant of electric field maximum with a zero momentum. After determining the quantum final momentum distribution of tunnel ionized electrons we show that the two-step model fails to predict the correct final momentum. Accordingly we suggest how to correct the two-step model. Furthermore, we determine the instant at which tunnel ionization starts, which turns out to be different from the instant usually assumed. From determining the instant at which it is most probable for the electron to enter the tunneling barrier and the instant at which it exits we determine the most probable time spent under the barrier. Moreover, we apply a quantum clock approach in order to determine the duration of tunnel ionization. From the quantum clock we determine an average tunneling time which is different in magnitude and origin with respect to the most probable tunneling time. By defining a probability distribution of tunneling times using virtual detectors we relate both methods and explain the apparent discrepancy. The results found have in general an effect on the interpretation of experiments that measure the spectra of tunnel ionized electrons, and specifically on the calibration of the so called attoclock experiments, because models with imprecise assumptions are usually employed in order to interpret experimental results.

  7. Tunneling time, exit time and exit momentum in strong field tunnel ionization

    Energy Technology Data Exchange (ETDEWEB)

    Teeny, Nicolas

    2016-10-18

    Tunnel ionization belongs to the fundamental processes of atomic physics. It is still an open question when does the electron tunnel ionize and how long is the duration of tunneling. In this work we solve the time-dependent Schroedinger equation in one and two dimensions and use ab initio quantum calculations in order to answer these questions. Additionally, we determine the exit momentum of the tunnel ionized electron from first principles. We find out results that are different from the assumptions of the commonly employed two-step model, which assumes that the electron ionizes at the instant of electric field maximum with a zero momentum. After determining the quantum final momentum distribution of tunnel ionized electrons we show that the two-step model fails to predict the correct final momentum. Accordingly we suggest how to correct the two-step model. Furthermore, we determine the instant at which tunnel ionization starts, which turns out to be different from the instant usually assumed. From determining the instant at which it is most probable for the electron to enter the tunneling barrier and the instant at which it exits we determine the most probable time spent under the barrier. Moreover, we apply a quantum clock approach in order to determine the duration of tunnel ionization. From the quantum clock we determine an average tunneling time which is different in magnitude and origin with respect to the most probable tunneling time. By defining a probability distribution of tunneling times using virtual detectors we relate both methods and explain the apparent discrepancy. The results found have in general an effect on the interpretation of experiments that measure the spectra of tunnel ionized electrons, and specifically on the calibration of the so called attoclock experiments, because models with imprecise assumptions are usually employed in order to interpret experimental results.

  8. Transonic Dynamics Tunnel (TDT)

    Data.gov (United States)

    Federal Laboratory Consortium — The Transonic Dynamics Tunnel (TDT) is a continuous flow wind-tunnel facility capable of speeds up to Mach 1.2 at stagnation pressures up to one atmosphere. The TDT...

  9. Quantum theory of tunneling

    CERN Document Server

    Razavy, Mohsen

    2014-01-01

    In this revised and expanded edition, in addition to a comprehensible introduction to the theoretical foundations of quantum tunneling based on different methods of formulating and solving tunneling problems, different semiclassical approximations for multidimensional systems are presented. Particular attention is given to the tunneling of composite systems, with examples taken from molecular tunneling and also from nuclear reactions. The interesting and puzzling features of tunneling times are given extensive coverage, and the possibility of measurement of these times with quantum clocks are critically examined. In addition by considering the analogy between evanescent waves in waveguides and in quantum tunneling, the times related to electromagnetic wave propagation have been used to explain certain aspects of quantum tunneling times. These topics are treated in both non-relativistic as well as relativistic regimes. Finally, a large number of examples of tunneling in atomic, molecular, condensed matter and ...

  10. Hypersonic Tunnel Facility (HTF)

    Data.gov (United States)

    Federal Laboratory Consortium — The Hypersonic Tunnel Facility (HTF) is a blow-down, non-vitiated (clean air) free-jet wind tunnel capable of testing large-scale, propulsion systems at Mach 5, 6,...

  11. Resonance tunneling electron-vibrational spectroscopy of polyoxometalates.

    Science.gov (United States)

    Dalidchik, F I; Kovalevskii, S A; Balashov, E M

    2017-05-21

    The tunneling spectra of the ordered monolayer films of decamolybdodicobaltate (DMDC) compounds deposited from aqueous solutions on HOPG were measured by scanning tunnel microscopy in air. The DMDC spectra, as well as the tunneling spectra of other polyoxometalates (POMs), exhibit well-defined negative differential resistances (NDRs). The mechanism of formation of these spectral features was established from the collection of revealed NDR dependences on the external varying parameters and found to be common to all systems exhibiting Wannier-Stark localization. A model of biresonance tunneling was developed to provide an explanation for the totality of experimental data, both the literature and original, on the tunneling POM probing. A variant of the tunneling electron-vibrational POM spectroscopy was proposed allowing the determination of the three basic energy parameters-energy gaps between the occupied and unoccupied states, frequencies of the vibrational transitions accompanying biresonance electron-tunneling processes, and electron-vibrational interaction constants on the monomolecular level.

  12. Corrective Action Decision Document/Closure Report for Corrective Action Unit 477: Area 12 N-Tunnel Muckpile, Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2010-03-15

    This Corrective Action Decision Document (CADD)/Closure Report (CR) was prepared by the Defense Threat Reduction Agency (DTRA) for Corrective Action Unit (CAU) 477, N-Tunnel Muckpile. This CADD/CR is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO) agreed to by the State of Nevada, the U.S. Department of Energy, and the U.S. Department of Defense. Corrective Action Unit 477 is comprised of one Corrective Action Site (CAS): • 12-06-03, Muckpile The purpose of this CADD/CR is to provide justification and documentation supporting the recommendation for closure with no further action, by placing use restrictions on CAU 477.

  13. Reliability of a semi-automated 3D-CT measuring method for tunnel diameters after anterior cruciate ligament reconstruction: A comparison between soft-tissue single-bundle allograft vs. autograft.

    Science.gov (United States)

    Robbrecht, Cedric; Claes, Steven; Cromheecke, Michiel; Mahieu, Peter; Kakavelakis, Kyriakos; Victor, Jan; Bellemans, Johan; Verdonk, Peter

    2014-10-01

    Post-operative widening of tibial and/or femoral bone tunnels is a common observation after ACL reconstruction, especially with soft-tissue grafts. There are no studies comparing tunnel widening in hamstring autografts versus tibialis anterior allografts. The goal of this study was to observe the difference in tunnel widening after the use of allograft vs. autograft for ACL reconstruction, by measuring it with a novel 3-D computed tomography based method. Thirty-five ACL-deficient subjects were included, underwent anatomic single-bundle ACL reconstruction and were evaluated at one year after surgery with the use of 3-D CT imaging. Three independent observers semi-automatically delineated femoral and tibial tunnel outlines, after which a best-fit cylinder was derived and the tunnel diameter was determined. Finally, intra- and inter-observer reliability of this novel measurement protocol was defined. In femoral tunnels, the intra-observer ICC was 0.973 (95% CI: 0.922-0.991) and the inter-observer ICC was 0.992 (95% CI: 0.982-0.996). In tibial tunnels, the intra-observer ICC was 0.955 (95% CI: 0.875-0.985). The combined inter-observer ICC was 0.970 (95% CI: 0.987-0.917). Tunnel widening was significantly higher in allografts compared to autografts, in the tibial tunnels (p=0.013) as well as in the femoral tunnels (p=0.007). To our knowledge, this novel, semi-automated 3D-computed tomography image processing method has shown to yield highly reproducible results for the measurement of bone tunnel diameter and area. This series showed a significantly higher amount of tunnel widening observed in the allograft group at one-year follow-up. Level II, Prospective comparative study. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Evaluation of 222radon occupational exposure in underground workplaces: tunnels used for mushroom cultivation in Italy

    International Nuclear Information System (INIS)

    Fontana, C.; Vecchiariello, S.; Angeloni, U.; Trevisi, R.; Tonnarini, S.

    2006-01-01

    The mushroom cultivation in tunnels represents a working activity with interesting characteristics from a radiological protection point of view. The practice of using tunnels or caves for the cultivation of mushrooms is diffused in many countries as well as in several Italian regions. These places are characterized by micro climate conditions (temperature, humidity, etc.) particularly adapted for the growth of mushrooms in every period of the year. This practice, like every working activity carried out in underground workplaces, is regulated by the Italian implementation of the European Union Basic Safety Standards (E.U. B.S.S., 1996). With the aim to evaluate the 222 Rn exposure of workers in tunnels used for mushroom cultivation, a study has been undertaken. In particular, hygienic and micro climatic characteristics (depth, temperature, relative humidity, barometric pressure, ventilation, etc.) and radiometric parameters (indoor radon concentration, radon decay products concentration, equilibrium factor F) have been investigated. In the present paper, the results of the two steps of the study are reported. In the first step, an operative protocol has been defined: the protocol was put through a series of measurements in two tuff tunnels in the area of Rome. In the second step, several tunnels used for mushroom cultivation, located in different Italian regions, have been monitored and experimental data have been used to estimate annual effective doses of workers due to radon inhalation.The experimental results have been analyzed in the context of the E.U. B.S.S

  15. Snow and ice blocking of tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Lia, Leif

    1998-12-31

    Hydroelectric power development in cold regions causes much concern about operational reliability and dam safety. This thesis studies the temperature distribution in tunnels by means of air temperature measurements in six tunnel spillways and five diversion tunnels. The measurements lasted for two consecutive winters. The air through flow tunnel is used as it causes cooling of both rock and water. In open spillway tunnels, frost reaches the entire tunnel. In spillway tunnels with walls, the frost zones reach about 100 m from the downstream end. In mildly-inclined diversion tunnels, a frost free zone is located in the middle of the tunnel and snow and ice problems were only observed in the inlet and outlet. Severe aufeis is accumulation is observed in the frost zones. The heat transfer from rock to air, water and ice is calculated and used in a prediction model for the calculation of aufeis build-up together with local field observation data. The water penetration of snow plugs is also calculated, based on the heat balance. It takes 20 to 50 days for water to enter the blocked tunnel. The empirical values are 30 to 60 days, but only 1 day if the temperature of the snow pack is 0{sup o}C. Sensitivity analyses are carried out for temperature variations in rock, snow, water and ice. Systematic field observation shows that it is important for hydropower companies to know about the effects of snow and ice blocking in an area. A risk analysis of dam safety is presented for a real case. Finally, the thesis proposes solutions which can reduce the snow and ice problems. 79 refs., 63 figs., 11 tabs.

  16. Research on Access Zone Luminance of Expressway Tunnel in Southwest Mountainous Areas of Zhejiang Province%浙西南山区高速公路隧道洞外亮度研究

    Institute of Scientific and Technical Information of China (English)

    涂耘; 王少飞; 侯伶; 张琦; 蔡坚健; 谢晓辉; 刘琦; 潘永杰

    2012-01-01

    The shortcomings for traditional measurement method of L20(S)are analyzed,and a novel measurement method of L20(S)based digital technology is introduced,making large-scale and high efficiency measurement is possible. Using this method and means test lighting environment of road tunnels in Jin-Li-Wen and Liang-Long Expressway,and recommended value of L20(S)in southwest mountainous areas of Zhejiang Province is put forward,it can provide the reference for energy-saving operation and transformation design of road tunnel lighting system. Based on landscape theory,measures are also proposed to reduce light for access zone that consistent with "environmentally friendly"designing philosophy of expressway tunnel in mountainous areas. This research result has the better economic and social and ecological benefits that can be fully application in practical engineering.%在分析传统公路隧道洞外亮度L20(S)测算方法不足的基础上,介绍一种基于数码技术的公路隧道洞外亮度L20(S)测试方法,使得大规模、高效率地实测公路隧道洞外亮度L20(S)成为可能.采用上述方法和手段对金丽温、两龙高速公路隧道洞口光环境进行实测,提出浙西南山区高速公路隧道洞外亮度L20(S)建议值,可供高速公路隧道照明系统节能运营及改造设计时参考.基于环境景观理论,提出符合“环境友好型”山区高速公路隧道设计理念的接近段减光措施.研究成果具有较好的经济效益、社会效益和生态效益,可在实际工程中全面推广应用.

  17. Cost comparison between Subterrene and current tunneling methods. Final report

    International Nuclear Information System (INIS)

    Bledsoe, J.D.; Hill, J.E.; Coon, R.F.

    1975-05-01

    A study was made to compare tunnel construction costs between the Subterrene tunneling system and methods currently in use. Three completed tunnels were selected for study cases to represent finished diameters ranging from 3.05 meters (10 feet) to 6.25 meters (20.5 feet). The study cases were normalized by deleting extraneous work and assigning labor, equipment, and materials costs for the Southern California area in 1974. Detailed cost estimates (shown in Appendix A) were then made for the three tunnels for baseline. A conceptual nuclear powered Subterrene tunneling machine (NSTM) was designed. It was assumed that NSTM's were available for each of the three baseline tunnels. Costs were estimated (shown in Appendix B) for the baseline tunnels driven by NSTM

  18. 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

  19. Analysis of neural mechanisms underlying verbal fluency in cytoarchitectonically defined stereotaxic space--the roles of Brodmann areas 44 and 45.

    Science.gov (United States)

    Amunts, Katrin; Weiss, Peter H; Mohlberg, Hartmut; Pieperhoff, Peter; Eickhoff, Simon; Gurd, Jennifer M; Marshall, John C; Shah, Nadim J; Fink, Gereon R; Zilles, Karl

    2004-05-01

    We investigated neural activations underlying a verbal fluency task and cytoarchitectonic probabilistic maps of Broca's speech region (Brodmann's areas 44 and 45). To do so, we reanalyzed data from a previous functional magnetic resonance imaging (fMRI) [Brain 125 (2002) 1024] and from a cytoarchitectonic study [J. Comp. Neurol. 412 (1999) 319] and developed a method to combine both data sets. In the fMRI experiment, verbal fluency was investigated in 11 healthy volunteers, who covertly produced words from predefined categories. A factorial design was used with factors verbal class (semantic vs. overlearned fluency) and switching between categories (no vs. yes). fMRI data analysis employed SPM99 (Statistical Parametric Mapping). Cytoarchitectonic maps of areas 44 and 45 were derived from histologic sections of 10 postmortem brains. Both the in vivo fMRI and postmortem MR data were warped to a common reference brain using a new elastic warping tool. Cytoarchitectonic probability maps with stereotaxic information about intersubject variability were calculated for both areas and superimposed on the functional data, which showed the involvement of left hemisphere areas with verbal fluency relative to the baseline. Semantic relative to overlearned fluency showed greater involvement of left area 45 than of 44. Thus, although both areas participate in verbal fluency, they do so differentially. Left area 45 is more involved in semantic aspects of language processing, while area 44 is probably involved in high-level aspects of programming speech production per se. The combination of functional data analysis with a new elastic warping tool and cytoarchitectonic maps opens new perspectives for analyzing the cortical networks involved in language.

  20. Quantum tunneling time

    International Nuclear Information System (INIS)

    Wang, Z.S.; Lai, C.H.; Oh, C.H.; Kwek, L.C.

    2004-01-01

    We present a calculation of quantum tunneling time based on the transition duration of wave peak from one side of a barrier to the other. In our formulation, the tunneling time comprises a real and an imaginary part. The real part is an extension of the phase tunneling time with quantum corrections whereas the imaginary time is associated with energy derivatives of the probability amplitudes

  1. Charge Islands Through Tunneling

    Science.gov (United States)

    Robinson, Daryl C.

    2002-01-01

    It has been recently reported that the electrical charge in a semiconductive carbon nanotube is not evenly distributed, but rather it is divided into charge "islands." This paper links the aforementioned phenomenon to tunneling and provides further insight into the higher rate of tunneling processes, which makes tunneling devices attractive. This paper also provides a basis for calculating the charge profile over the length of the tube so that nanoscale devices' conductive properties may be fully exploited.

  2. Josephson tunneling and nanosystems

    OpenAIRE

    Ovchinnikov, Yurii; Kresin, Vladimir

    2010-01-01

    Josephson tunneling between nanoclusters is analyzed. The discrete nature of the electronic energy spectra, including their shell ordering, is explicitly taken into account. The treatment considers the two distinct cases of resonant and non-resonant tunneling. It is demonstrated that the current density greatly exceeds the value discussed in the conventional theory. Nanoparticles are shown to be promising building blocks for nanomaterials-based tunneling networks.

  3. About tunnelling times

    International Nuclear Information System (INIS)

    Olkhovsky, V.S.; Recami, E.

    1991-08-01

    In this paper, first we critically analyse the main theoretical definitions and calculations of the sub-barrier tunnelling and reflection times. Secondly, we propose a new, physically sensible definition of such durations, on the basis of a recent general formalism (already tested for other types of quantum collisions). At last, we discuss some results regarding temporal evolution of the tunnelling processes, and in particular the ''particle'' speed during tunnelling. (author). 36 refs, 1 fig

  4. Distribution of tunnelling times for quantum electron transport

    International Nuclear Information System (INIS)

    Rudge, Samuel L.; Kosov, Daniel S.

    2016-01-01

    In electron transport, the tunnelling time is the time taken for an electron to tunnel out of a system after it has tunnelled in. We define the tunnelling time distribution for quantum processes in a dissipative environment and develop a practical approach for calculating it, where the environment is described by the general Markovian master equation. We illustrate the theory by using the rate equation to compute the tunnelling time distribution for electron transport through a molecular junction. The tunnelling time distribution is exponential, which indicates that Markovian quantum tunnelling is a Poissonian statistical process. The tunnelling time distribution is used not only to study the quantum statistics of tunnelling along the average electric current but also to analyse extreme quantum events where an electron jumps against the applied voltage bias. The average tunnelling time shows distinctly different temperature dependence for p- and n-type molecular junctions and therefore provides a sensitive tool to probe the alignment of molecular orbitals relative to the electrode Fermi energy.

  5. Microsystem Aeromechanics Wind Tunnel

    Data.gov (United States)

    Federal Laboratory Consortium — The Microsystem Aeromechanics Wind Tunnel advances the study of fundamental flow physics relevant to micro air vehicle (MAV) flight and assesses vehicle performance...

  6. Projection operator method for collective tunneling transitions

    International Nuclear Information System (INIS)

    Kohmura, Toshitake; Ohta, Hirofumi; Hashimoto, Yukio; Maruyama, Masahiro

    2002-01-01

    Collective tunneling transitions take place in the case that a system has two nearly degenerate ground states with a slight energy splitting, which provides the time scale of the tunneling. The Liouville equation determines the evolution of the density matrix, while the Schroedinger equation determines that of a state. The Liouville equation seems to be more powerful for calculating accurately the energy splitting of two nearly degenerate eigenstates. However, no method to exactly solve the Liouville eigenvalue equation has been established. The usual projection operator method for the Liouville equation is not feasible. We analytically solve the Liouville evolution equation for nuclear collective tunneling from one Hartree minimum to another, proposing a simple and solvable model Hamiltonian for the transition. We derive an analytical expression for the splitting of energy eigenvalues from a spectral function of the Liouville evolution using a half-projected operator method. A full-order analytical expression for the energy splitting is obtained. We define the collective tunneling path of a microscopic Hamiltonian for collective tunneling, projecting the nuclear ground states onto n-particle n-hole state spaces. It is argued that the collective tunneling path sector of a microscopic Hamiltonian can be transformed into the present solvable model Hamiltonian. (author)

  7. Spatial landuse planning using land evaluation and dynamic system to define sustainable area of paddy field: Case study in Karawang Regency, West Java, Indonesia

    Science.gov (United States)

    Widiatmaka, Widiatmaka; Ambarwulan, Wiwin; Firmansyah, Irman; Munibah, Khursatul; Santoso, Paulus B. K.

    2015-04-01

    Indonesia is the country with the 4th largest population in the worlds; the population reached more than 237 million people. With rice as the staple food for more than 95 percent of the population, there is an important role of paddy field in Indonesian food security. Actually, paddy field in Java has produced 52,6% of the total rice production in Indonesia, showing the very high dependence of Indonesia on food production from paddy fields in Java island. Karawang Regency is one of the regions in West Java Province that contribute to the national food supply, due to its high soil fertility and its high extent of paddy field. Dynamics of land use change in this region are high because of its proximity to urban area; this dynamics has led to paddy field conversion to industry and residential landuse, which in turn change the regional rice production capacity. Decreasing paddy field landuse in this region could be serve as an example case of the general phenomena which occurred in Javanese rice production region. The objective of this study were: (i) to identify the suitable area for paddy field, (ii) to modelize the decreasing of paddy field in socio-economic context of the region, and (iii) to plan the spatial priority area of paddy field protection according to model prediction. A land evaluation for paddy was completed after a soil survey, while IKONOS imagery was analyzed to delineate paddy fields. Dynamic system model of paddy field land use is built, and then based on the model built, the land area of paddy field untill 2040 in some scenarios was developped. The research results showed that the land suitability class for paddy fields in Karawang Regency ranged from very suitable (S1) to marginally suitable (S3), with various land characteristics as limiting factors. The model predicts that if the situation of paddy field land use change continues in its business as usual path, paddy field area that would exist in the region in 2040 will stay half of the recent

  8. Spatial distribution of trachoma cases in the City of Bauru, State of São Paulo, Brazil, detected in 2006: defining key areas for improvement of health resources

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Macharelli

    2013-04-01

    Full Text Available Introduction The objective of this study was to analyze the spatial behavior of the occurrence of trachoma cases detected in the City of Bauru, State of São Paulo, Brazil, in 2006 in order to use the information collected to set priority areas for optimization of health resources. Methods the trachoma cases identified in 2006 were georeferenced. The data evaluated were: schools where the trachoma cases studied, data from the 2000 Census, census tract, type of housing, water supply conditions, distribution of income and levels of education of household heads. In the Google Earth® software and TerraView® were made descriptive spatial analysis and estimates of the Kernel. Each area was studied by interpolation of the density surfaces exposing events to facilitate to recognize the clusters. Results Of the 66 cases detected, only one (1.5% was not a resident of the city's outskirts. A positive association was detected of trachoma cases and the percentage of heads of household with income below three minimum wages and schooling under eight years of education. Conclusions The recognition of the spatial distribution of trachoma cases coincided with the areas of greatest social inequality in Bauru City. The micro-areas identified are those that should be prioritized in the rationalization of health resources. There is the possibility of using the trachoma cases detected as an indicator of performance of micro priority health programs.

  9. Spatial distribution of trachoma cases in the City of Bauru, State of São Paulo, Brazil, detected in 2006: defining key areas for improvement of health resources

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Macharelli

    2013-02-01

    Full Text Available Introduction The objective of this study was to analyze the spatial behavior of the occurrence of trachoma cases detected in the City of Bauru, State of São Paulo, Brazil, in 2006 in order to use the information collected to set priority areas for optimization of health resources. Methods the trachoma cases identified in 2006 were georeferenced. The data evaluated were: schools where the trachoma cases studied, data from the 2000 Census, census tract, type of housing, water supply conditions, distribution of income and levels of education of household heads. In the Google Earth® software and TerraView® were made descriptive spatial analysis and estimates of the Kernel. Each area was studied by interpolation of the density surfaces exposing events to facilitate to recognize the clusters. Results Of the 66 cases detected, only one (1.5% was not a resident of the city's outskirts. A positive association was detected of trachoma cases and the percentage of heads of household with income below three minimum wages and schooling under eight years of education. Conclusions The recognition of the spatial distribution of trachoma cases coincided with the areas of greatest social inequality in Bauru City. The micro-areas identified are those that should be prioritized in the rationalization of health resources. There is the possibility of using the trachoma cases detected as an indicator of performance of micro priority health programs.

  10. Air quality assessment in Salim Slam Tunnel

    International Nuclear Information System (INIS)

    El-Fadel, M.; Hashisho, Z.; Saikaly, P.

    1999-01-01

    Full text.Vehicle emissions constitute a serious occupational environmental hazard particularly in confined spaces such as tunnels and underground parking garages. these emissions at elevated concentrations, can cause adverse health effects, which range from nausea and eye irritation to mutagenicity, carcinogenicity and even death. This paper presents an environmental air quality assessment in a tunnel located in a highly congested urban area. For this purpose, air samples were collected and analyzed for the presence of primary air pollutants, priority metals, and volatile organic carbons. Air quality modeling was conducted to simulate variations of pollutant concentrations in the tunnel under worst case scenarios including traffic congestion and no air ventilation. Field measurements and mathematical simulation results were used to develop a strategy for proper air quality management in tunnels

  11. Thermodynamics of phonon-modulated tunneling centers

    International Nuclear Information System (INIS)

    Junker, W.; Wagner, M.

    1989-01-01

    In recent years tunneling centers have frequently been used to explain the unusual thermodynamic properties of disordered materials; in these approaches, however, the effect of the tunneling-phonon interaction is neglected. The present study considers the archetype model of phono-assisted tunneling, which is well known from other areas of tunneling physics (quantum diffusion, etc.). It is shown that the full thermodynamic information can be rigorously extracted from a single Green function. An extended factorization procedure beyond Hartree-Fock is introduced, which is checked by sum rules as well as by exact Goldberger-Adams expansions. The phonon-modulated internal energy and specific heat are calculated for different power-law coupling setups

  12. 9th January 2012 - Indonesian Extraordinary and Plenipotentiary Ambassador Triansyah Djani to to the United Nations, WTO and other International Organisations in Geneva signing the guest book with Head of International Relations F. Pauss and Adviser E. Tsesmelis, visiting the LHC tunnel at Point 5 and CMS underground experimental area with Collaboration Spokesperson J. Incandela.

    CERN Document Server

    Estelle Spirig

    2012-01-01

    9th January 2012 - Indonesian Extraordinary and Plenipotentiary Ambassador Triansyah Djani to to the United Nations, WTO and other International Organisations in Geneva signing the guest book with Head of International Relations F. Pauss and Adviser E. Tsesmelis, visiting the LHC tunnel at Point 5 and CMS underground experimental area with Collaboration Spokesperson J. Incandela.

  13. 10 February 2012 - Permanent Representative of the Republic of India to the Conference on Disarmament, United Nations Office at Geneva Ambassador Mehta signing the guest book with International Relations Adviser R. Voss;in the LHC tunnel at Point 2 and ALICE underground experimental area with Collaboration Deputy Spokesperson Y. Schutz.

    CERN Document Server

    Maximilien Brice

    2012-01-01

    10 February 2012 - Permanent Representative of the Republic of India to the Conference on Disarmament, United Nations Office at Geneva Ambassador Mehta signing the guest book with International Relations Adviser R. Voss;in the LHC tunnel at Point 2 and ALICE underground experimental area with Collaboration Deputy Spokesperson Y. Schutz.

  14. 14 November 2013 - Director of Indian Institute of Technology Indore P. Mathur with members of the Indian community working at CERN; visiting the LHC tunnel at Point 2, the ALICE experimental area and SM18 with ALICE Collaboration Spokesperson, Istituto Nazionale Fisica Nucleare P. Giubellino and Technology Department, Accelerator Beam Transfer Group Leader V. Mertens

    CERN Multimedia

    Jean-Claude Gadmer

    2013-01-01

    14 November 2013 - Director of Indian Institute of Technology Indore P. Mathur with members of the Indian community working at CERN; visiting the LHC tunnel at Point 2, the ALICE experimental area and SM18 with ALICE Collaboration Spokesperson, Istituto Nazionale Fisica Nucleare P. Giubellino and Technology Department, Accelerator Beam Transfer Group Leader V. Mertens

  15. Proposal for the award of a contract for the design, supply, installation and commissioning of a ventilation and air conditioning system for the ECN3 experimental area and the TCC8 and GHN300 service tunnels and for the dismantling of the existing system

    CERN Document Server

    2014-01-01

    Proposal for the award of a contract for the design, supply, installation and commissioning of a ventilation and air conditioning system for the ECN3 experimental area and the TCC8 and GHN300 service tunnels and for the dismantling of the existing system

  16. 18 January 2011 - Ing. Vittorio Malacalza, ASG Superconductors S.p.A, Italy in the LHC superconducting magnet test hall with Deputy Department Head L. Rossi, in the LHC tunnel at Point 5 and CMS experimental area with Spokesperson G. Tonelli.

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    18 January 2011 - Ing. Vittorio Malacalza, ASG Superconductors S.p.A, Italy in the LHC superconducting magnet test hall with Deputy Department Head L. Rossi, in the LHC tunnel at Point 5 and CMS experimental area with Spokesperson G. Tonelli.

  17. 14 February 2012 - Ambassadors from Algeria, Brunei Darussalam, Canada, Chad, Tunisia, Permanent Representatives to the United Nations Office at Geneva in the LHC tunnel at Point 1, ATLAS visitor centre, and ATLAS underground experimental area, throughout accompanied by Advisers P. Fassnacht, E. Tsesmelis and R. Voss

    CERN Multimedia

    Jean-Claude Gadmer

    2012-01-01

    14 February 2012 - Ambassadors from Algeria, Brunei Darussalam, Canada, Chad, Tunisia, Permanent Representatives to the United Nations Office at Geneva in the LHC tunnel at Point 1, ATLAS visitor centre, and ATLAS underground experimental area, throughout accompanied by Advisers P. Fassnacht, E. Tsesmelis and R. Voss

  18. A Vision in Aeronautics: The K-12 Wind Tunnel Project

    Science.gov (United States)

    1997-01-01

    A Vision in Aeronautics, a project within the NASA Lewis Research Center's Information Infrastructure Technologies and Applications (IITA) K-12 Program, employs small-scale, subsonic wind tunnels to inspire students to explore the world of aeronautics and computers. Recently, two educational K-12 wind tunnels were built in the Cleveland area. During the 1995-1996 school year, preliminary testing occurred in both tunnels.

  19. Tunneling beyond the Fermilab site

    International Nuclear Information System (INIS)

    Baker, S.; Elwyn, A.; Lach, J.; Read, A.

    1983-01-01

    An accelerator that crosses the Fermilab site boundary must have a minimum effect on the surrounding environment and the people residing in the area. Unobstructed public access should be allowed above the ring except in relatively few areas such as the injection, dump, and experimental regions. The accelerator should be a benign and unobtrusive neighbor not only when it is completed but also in the construction period. For these reasons underground tunneling for all or most of the ring seems attractive. In this note we look into some questions raised by tunneling beyond the Fermilab site. Most of our discussion is of general applicability. However, we will use as examples two specific ring configurations. The examples have not been optimized from the point of view of physics output or accelerator technology but are just specific examples which allow us to study questions of tunneling. One is a ring of 5 km radius (5 TeV) tangent to the Tevatron and entirely east of the Fox River and fed by a beam from the Tevatron which crosses under the river. We assume that each of these machines will have 100 beam fills per year and we scale the maximum intensities with the accelerator radii. Thus we assume that there will be 1.0 E14 protons in each beam of the 20 TeV machine and 2.5 E13 for the 5 TeV machine

  20. Underwater piercing of a tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Solvik, O.

    1984-11-01

    Norwegian consultants and contractors have been confronted with the task of blasting a final penetrating passage that will open the way for the water in a reservoir to flow through the hydropower turbines. Norway has almost certainly led in this area because of its special topographical and geological conditions. The glacial activities have created a number of natural and very deep lakes forming cheap reservoirs. Piercings at depths up to about 100 m have been performed. Problems tend to increase with depth, but unsuccessful penetration can occur at any depth. Secondary effects to consider include the danger of slides when the water level is lowered, wave erosion along the lowered new shoreline, erosion at all streams and rivers flowing into the lake and groundwater erosion in the newly exposed dry shoreline. Methods of penetration can be roughly divided into two categories: penetration against the open tunnel shaft (open system); and penetration against the closed tunnel shaft (closed system). 6 figures.

  1. Electron tunneling in chemistry

    International Nuclear Information System (INIS)

    Zamaraev, K.I.; Khajrutdinov, R.F.; Zhdanov, V.P.; Molin, Yu.N.

    1985-01-01

    Results of experimental and theoretical investigations are outlined systematically on electron tunnelling in chemical reactions. Mechanism of electron transport to great distances is shown to be characteristic to chemical compounds of a wide range. The function of tunnel reactions is discussed for various fields of chemistry, including radiation chemistry, electrochemistry, chemistry of solids, chemistry of surface and catalysis

  2. Empowerment Zones and Enterprise Districts, Enterprise Zones (EZ) are areas defined by the Department of Economic Development (LDED) for the purpose of encouraging economic growth by offering tax credits and incentives to businesses locating or expanding in designated enterprise zone areas., Published in 2005, 1:24000 (1in=2000ft) scale, Louisiana State University (LSU).

    Data.gov (United States)

    NSGIC Education | GIS Inventory — Empowerment Zones and Enterprise Districts dataset current as of 2005. Enterprise Zones (EZ) are areas defined by the Department of Economic Development (LDED) for...

  3. Tunnel fire dynamics

    CERN Document Server

    Ingason, Haukur; Lönnermark, Anders

    2015-01-01

    This book covers a wide range of issues in fire safety engineering in tunnels, describes the phenomena related to tunnel fire dynamics, presents state-of-the-art research, and gives detailed solutions to these major issues. Examples for calculations are provided. The aim is to significantly improve the understanding of fire safety engineering in tunnels. Chapters on fuel and ventilation control, combustion products, gas temperatures, heat fluxes, smoke stratification, visibility, tenability, design fire curves, heat release, fire suppression and detection, CFD modeling, and scaling techniques all equip readers to create their own fire safety plans for tunnels. This book should be purchased by any engineer or public official with responsibility for tunnels. It would also be of interest to many fire protection engineers as an application of evolving technical principles of fire safety.

  4. A regulatory hydrophobic area in the flexible joint region of plasminogen activator inhibitor-1, defined with fluorescent activity-neutralizing ligands. Ligand-induced serpin polymerization

    DEFF Research Database (Denmark)

    Egelund, R; Einholm, A P; Pedersen, K E

    2001-01-01

    by all tested nonfluorescent neutralizers, indicating that all neutralizers bind to a common hydrophobic area preferentially accessible in active PAI-1. Activity neutralization proceeded through two consecutive steps as follows: first step is conversion to forms displaying substrate behavior toward u......PA, and second step is to forms inert to uPA. With some neutralizers, the second step was associated with PAI-1 polymerization. Vitronectin reduced the susceptibility to the neutralizers. Changes in sensitivity to activity neutralization by point mutations were compatible with the various neutralizers having...

  5. 16 March 2009 - HRH Princess Maha Chakri Sirindhorn, Kingdom of Thailand, visiting CMS experimental area and LHC tunnel with Coordinator for external relations F. Pauss and Collaboration Spokesperson T. Virdee.

    CERN Multimedia

    Maximilien Brice

    2009-01-01

    Photo 1: Relations with Non-Member State E. Tsesmelis, CMS Collaboration Spokesperson T. Virdee, HRH Princess Maha Chakri Sirindhorn and Coordinator for External relations F. Pauss, in CMS experimental area. Photo 2-12: Arrival of HRH at building 160: Posy presented to HRH by E. and F. Breedon; Welcome line: Director-General R. Heuer who introduces S. Bertolucci, F. Pauss, E. Tsesmelis, A. de Roeck, R. Breedon and Protocol Officer W. Korda. Photo 13-26:Presentation by Director-General R. Heuer and Head of Education R. Landua. Photo 27-30: Welcome at CMS by Spokesperson T. Virdee Photo 31-43: LHC tunnel visit Photo 44 - 60: CMS underground area visit Photo 61-63: HRH signs the guest book in the SCX5 conference room Photo 64-69: Signature of an expression of interest between SLRI and CMS Photo 75-88: Final discussion with Coordinator for External relation F. Pauss and Director-General R. Heuer.

  6. ["Knowing about AIDS" and sexual precautions among low-income women from the southern area of Buenos Aires. Notes for defining prevention policies].

    Science.gov (United States)

    Grimberg, M

    2001-01-01

    This study is part of a line of research on gender and prevention in a research program on the social construction of HIV/AIDS. We present the results of an ethnographic study among low-income women 15-35 years old in the southern area of Buenos Aires. The area has the highest number of HIV/AIDS cases and high poverty levels, extensive social degradation, and urban violence. According to our results, in the interface between "knowing about" and "behaving" there are complex processes involving stigmatized and gender-biased representations of HIV/AIDS as "other people's problem" and social and sexual relations permeated by gender stereotypes and roles. We believe that planning of prevention should be based on the consideration of overall social practices and specifically the characteristics of gender relations, prioritizing relational strategies between women and men and promoting critical reflection on the main nodes organizing daily life and active participation in the production of social relations and practices of reciprocity and equity. The increasingly precarious conditions in social life intensifies poor women's vulnerability and social interaction contexts that relate to the socioeconomic and symbolic role played by women.

  7. Malaria hotspots defined by clinical malaria, asymptomatic carriage, PCR and vector numbers in a low transmission area on the Kenyan Coast.

    Science.gov (United States)

    Kangoye, David Tiga; Noor, Abdisalan; Midega, Janet; Mwongeli, Joyce; Mkabili, Dora; Mogeni, Polycarp; Kerubo, Christine; Akoo, Pauline; Mwangangi, Joseph; Drakeley, Chris; Marsh, Kevin; Bejon, Philip; Njuguna, Patricia

    2016-04-14

    Targeted malaria control interventions are expected to be cost-effective. Clinical, parasitological and serological markers of malaria transmission have been used to detect malaria transmission hotspots, but few studies have examined the relationship between the different potential markers in low transmission areas. The present study reports on the relationships between clinical, parasitological, serological and entomological markers of malaria transmission in an area of low transmission intensity in Coastal Kenya. Longitudinal data collected from 831 children aged 5-17 months, cross-sectional survey data from 800 older children and adults, and entomological survey data collected in Ganze on the Kenyan Coast were used in the present study. The spatial scan statistic test used to detect malaria transmission hotspots was based on incidence of clinical malaria episodes, prevalence of asymptomatic asexual parasites carriage detected by microscopy and polymerase chain reaction (PCR), seroprevalence of antibodies to two Plasmodium falciparum merozoite antigens (AMA1 and MSP1-19) and densities of Anopheles mosquitoes in CDC light-trap catches. There was considerable overlapping of hotspots by these different markers, but only weak to moderate correlation between parasitological and serological markers. PCR prevalence and seroprevalence of antibodies to AMA1 or MSP1-19 appeared to be more sensitive markers of hotspots at very low transmission intensity. These findings may support the choice of either serology or PCR as markers in the detection of malaria transmission hotspots for targeted interventions.

  8. Decline of Ecological Functions Performed by Dung Beetles in Areas of Atlantic Forest and Contribution of Rollers and Tunnellers in Organic Matter Removal.

    Science.gov (United States)

    Batilani-Filho, M; Hernandez, M I M

    2017-08-01

    The feeding behavior of the Scarabaeinae subfamily has positive implications on ecosystem functioning. We characterize the necrophagous and coprophagous dung beetle assemblages, and we quantify the removal of swine carrion and domestic dog dung in two areas with different degrees of environmental disturbance in an Atlantic Forest remnant located in Florianopolis, SC, Brazil. The experiment was setup at eight sampling points in each area, by installing one control and two collection and removal assessment arenas for collecting necrophagous dung beetles while simultaneously evaluating the removal of carrion (50 g of rotting pork for 48 h). We used the same sample design with 50 g of domestic dog dung for evaluating the coprophagous dung beetle assemblage and dung removal. Our results indicated that necrophagous dung beetles were more sensitive to environmental disturbance owing to a lower richness and changes in species dominance, which resulted in a lower removal in the areas with greater disturbance and lower environmental quality (39.6% carrion removal) in relation to less disturbed areas (75.1% carrion removal). The dung beetle assemblages were similar in structure and removal rates between areas (80% of dung was removed). In assessing the influence of richness, abundance, and biomass of dung beetles on resource removal both for the whole assemblage and for each separate functional guild, only the abundance and biomass of rollers contributed significantly to dung removal. These results highlight the implications of environmental disturbances on the functions of dung beetles, which respond differently according to the resource they use. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. 18 December 2012 -Portuguese President of FCT M. Seabra visiting the Computing Centre with IT Department Head F. Hemmer, ATLAS experimental area with Collaboration Spokesperson F. Gianotti and A. Henriques Correia, in the LHC tunnel at Point 2 and CMS experimental area with Deputy Spokesperson J. Varela, signing an administrative agreement with Director-General R. Heuer; LIP President J. M. Gago and Delegate to CERN Council G. Barreia present.

    CERN Multimedia

    Samuel Morier-Genoud

    2012-01-01

    18 December 2012 -Portuguese President of FCT M. Seabra visiting the Computing Centre with IT Department Head F. Hemmer, ATLAS experimental area with Collaboration Spokesperson F. Gianotti and A. Henriques Correia, in the LHC tunnel at Point 2 and CMS experimental area with Deputy Spokesperson J. Varela, signing an administrative agreement with Director-General R. Heuer; LIP President J. M. Gago and Delegate to CERN Council G. Barreia present.

  10. Ultrafast scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Botkin, D.A. [California Univ., Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley Lab., CA (United States)

    1995-09-01

    I have developed an ultrafast scanning tunneling microscope (USTM) based on uniting stroboscopic methods of ultrafast optics and scanned probe microscopy to obtain nanometer spatial resolution and sub-picosecond temporal resolution. USTM increases the achievable time resolution of a STM by more than 6 orders of magnitude; this should enable exploration of mesoscopic and nanometer size systems on time scales corresponding to the period or decay of fundamental excitations. USTM consists of a photoconductive switch with subpicosecond response time in series with the tip of a STM. An optical pulse from a modelocked laser activates the switch to create a gate for the tunneling current, while a second laser pulse on the sample initiates a dynamic process which affects the tunneling current. By sending a large sequence of identical pulse pairs and measuring the average tunnel current as a function of the relative time delay between the pulses in each pair, one can map the time evolution of the surface process. USTM was used to measure the broadband response of the STM`s atomic size tunnel barrier in frequencies from tens to hundreds of GHz. The USTM signal amplitude decays linearly with the tunnel junction conductance, so the spatial resolution of the time-resolved signal is comparable to that of a conventional STM. Geometrical capacitance of the junction does not appear to play an important role in the measurement, but a capacitive effect intimately related to tunneling contributes to the measured signals and may limit the ultimate resolution of the USTM.

  11. Are conventional statistical techniques exhaustive for defining metal background concentrations in harbour sediments? A case study: The Coastal Area of Bari (Southeast Italy).

    Science.gov (United States)

    Mali, Matilda; Dell'Anna, Maria Michela; Mastrorilli, Piero; Damiani, Leonardo; Ungaro, Nicola; Belviso, Claudia; Fiore, Saverio

    2015-11-01

    Sediment contamination by metals poses significant risks to coastal ecosystems and is considered to be problematic for dredging operations. The determination of the background values of metal and metalloid distribution based on site-specific variability is fundamental in assessing pollution levels in harbour sediments. The novelty of the present work consists of addressing the scope and limitation of analysing port sediments through the use of conventional statistical techniques (such as: linear regression analysis, construction of cumulative frequency curves and the iterative 2σ technique), that are commonly employed for assessing Regional Geochemical Background (RGB) values in coastal sediments. This study ascertained that although the tout court use of such techniques in determining the RGB values in harbour sediments seems appropriate (the chemical-physical parameters of port sediments fit well with statistical equations), it should nevertheless be avoided because it may be misleading and can mask key aspects of the study area that can only be revealed by further investigations, such as mineralogical and multivariate statistical analyses. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Tunnel magnetoresistance in alumina, magnesia and composite tunnel barrier magnetic tunnel junctions

    International Nuclear Information System (INIS)

    Schebaum, Oliver; Drewello, Volker; Auge, Alexander; Reiss, Guenter; Muenzenberg, Markus; Schuhmann, Henning; Seibt, Michael; Thomas, Andy

    2011-01-01

    Using magnetron sputtering, we have prepared Co-Fe-B/tunnel barrier/Co-Fe-B magnetic tunnel junctions with tunnel barriers consisting of alumina, magnesia, and magnesia-alumina bilayer systems. The highest tunnel magnetoresistance ratios we found were 73% for alumina and 323% for magnesia-based tunnel junctions. Additionally, tunnel junctions with a unified layer stack were prepared for the three different barriers. In these systems, the tunnel magnetoresistance ratios at optimum annealing temperatures were found to be 65% for alumina, 173% for magnesia, and 78% for the composite tunnel barriers. The similar tunnel magnetoresistance ratios of the tunnel junctions containing alumina provide evidence that coherent tunneling is suppressed by the alumina layer in the composite tunnel barrier. - Research highlights: → Transport properties of Co-Fe-B/tunnel barrier/Co-Fe-B magnetic tunnel junctions. → Tunnel barrier consists of MgO, Al-Ox, or MgO/Al-Ox bilayer systems. → Limitation of TMR-ratio in composite barrier tunnel junctions to Al-Ox values. → Limitation indicates that Al-Ox layer is causing incoherent tunneling.

  13. Interleaving of beam lines inside the PS tunnel

    CERN Multimedia

    1983-01-01

    View against the direction of the proton beams. The PS ring (section 26) is on the left. The injection tunnel for LEAR leaving from here has increased the trafic in this already busy area where the two Linacs and the transfer tunnel leading to the SPS, ISR and AA join the PS ring (cf. photo 7802260, 7802261, Annual Report 1981, p. 89, fig. 12).

  14. Cohort profile: 'Centenari a Trieste' (CaT), a study of the health status of centenarians in a small defined area of Italy.

    Science.gov (United States)

    Tettamanti, Mauro; Marcon, Gabriella

    2018-02-08

    Centenarians, a segment of the population which some 50 years ago comprised only a few individuals, now count thousands in many countries, and demographic projections forecast that this growth will continue. The study of this new population will give us new information on extreme longevity and help prepare for their health and social needs. The aim of the Centenari a Trieste study is to describe the health and health service use by centenarians, with specific focus on cognitive status. This is a population-based study of centenarians living in the province of Trieste (Italy), a small area with a high prevalence of centenarians and a close network of health and social services, which makes it possible to conduct a study. Consenting individuals were visited by a clinician, tested by neuropsychologists and also gave a sample of their blood. Administrative data were retrieved as well. Of the 163 centenarians, 70 could be contacted and participated in the study. The main reasons for non-participation were impossibility to contact the subject (70) and death (20). Centenarians were mostly women (90%), tended to live in a nursing home (60%) and were generally severely functionally impaired (Barthel Index <50: 61%). Data from the administrative database showed that about one out of five needed hospitalisation in the preceding year and more than three out of four had at least one drug prescription. In 2017, we started a new wave of the study enrolling people who had just become centenarian and reassessing subjects already seen; we hope to extend this recruitment in the next years. Subjects are now examined also by cardiologists and dental specialists. We are collecting further different biological specimens to investigate new hypotheses on the cognitive function of the centenarians. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  15. Vacuum phonon tunneling.

    Science.gov (United States)

    Altfeder, Igor; Voevodin, Andrey A; Roy, Ajit K

    2010-10-15

    Field-induced phonon tunneling, a previously unknown mechanism of interfacial thermal transport, has been revealed by ultrahigh vacuum inelastic scanning tunneling microscopy (STM). Using thermally broadened Fermi-Dirac distribution in the STM tip as in situ atomic-scale thermometer we found that thermal vibrations of the last tip atom are effectively transmitted to sample surface despite few angstroms wide vacuum gap. We show that phonon tunneling is driven by interfacial electric field and thermally vibrating image charges, and its rate is enhanced by surface electron-phonon interaction.

  16. Evaluation of {sup 222}radon occupational exposure in underground workplaces: tunnels used for mushroom cultivation in Italy

    Energy Technology Data Exchange (ETDEWEB)

    Fontana, C.; Vecchiariello, S.; Angeloni, U. [Laboratory of Environmental Radioactivity - Central Laboratory, ITALIAN RED CROSS, Rome (Italy); Trevisi, R.; Tonnarini, S. [Radon Measurement Laboratory - Department of Occupational Hygiene, ISPESL, Rome (Italy)

    2006-07-01

    The mushroom cultivation in tunnels represents a working activity with interesting characteristics from a radiological protection point of view. The practice of using tunnels or caves for the cultivation of mushrooms is diffused in many countries as well as in several Italian regions. These places are characterized by micro climate conditions (temperature, humidity, etc.) particularly adapted for the growth of mushrooms in every period of the year. This practice, like every working activity carried out in underground workplaces, is regulated by the Italian implementation of the European Union Basic Safety Standards (E.U. B.S.S., 1996). With the aim to evaluate the {sup 222}Rn exposure of workers in tunnels used for mushroom cultivation, a study has been undertaken. In particular, hygienic and micro climatic characteristics (depth, temperature, relative humidity, barometric pressure, ventilation, etc.) and radiometric parameters (indoor radon concentration, radon decay products concentration, equilibrium factor F) have been investigated. In the present paper, the results of the two steps of the study are reported. In the first step, an operative protocol has been defined: the protocol was put through a series of measurements in two tuff tunnels in the area of Rome. In the second step, several tunnels used for mushroom cultivation, located in different Italian regions, have been monitored and experimental data have been used to estimate annual effective doses of workers due to radon inhalation.The experimental results have been analyzed in the context of the E.U. B.S.S.

  17. Reducing the computational requirements for simulating tunnel fires by combining multiscale modelling and multiple processor calculation

    DEFF Research Database (Denmark)

    Vermesi, Izabella; Rein, Guillermo; Colella, Francesco

    2017-01-01

    Multiscale modelling of tunnel fires that uses a coupled 3D (fire area) and 1D (the rest of the tunnel) model is seen as the solution to the numerical problem of the large domains associated with long tunnels. The present study demonstrates the feasibility of the implementation of this method...... in FDS version 6.0, a widely used fire-specific, open source CFD software. Furthermore, it compares the reduction in simulation time given by multiscale modelling with the one given by the use of multiple processor calculation. This was done using a 1200m long tunnel with a rectangular cross......-section as a demonstration case. The multiscale implementation consisted of placing a 30MW fire in the centre of a 400m long 3D domain, along with two 400m long 1D ducts on each side of it, that were again bounded by two nodes each. A fixed volume flow was defined in the upstream duct and the two models were coupled...

  18. Quantum tunneling with friction

    Science.gov (United States)

    Tokieda, M.; Hagino, K.

    2017-05-01

    Using the phenomenological quantum friction models introduced by P. Caldirola [Nuovo Cimento 18, 393 (1941), 10.1007/BF02960144] and E. Kanai [Prog. Theor. Phys. 3, 440 (1948), 10.1143/ptp/3.4.440], M. D. Kostin [J. Chem. Phys. 57, 3589 (1972), 10.1063/1.1678812], and K. Albrecht [Phys. Lett. B 56, 127 (1975), 10.1016/0370-2693(75)90283-X], we study quantum tunneling of a one-dimensional potential in the presence of energy dissipation. To this end, we calculate the tunneling probability using a time-dependent wave-packet method. The friction reduces the tunneling probability. We show that the three models provide similar penetrabilities to each other, among which the Caldirola-Kanai model requires the least numerical effort. We also discuss the effect of energy dissipation on quantum tunneling in terms of barrier distributions.

  19. Wind Tunnel Testing Facilities

    Data.gov (United States)

    Federal Laboratory Consortium — NASA Ames Research Center is pleased to offer the services of our premier wind tunnel facilities that have a broad range of proven testing capabilities to customers...

  20. INCAS TRISONIC WIND TUNNEL

    Directory of Open Access Journals (Sweden)

    Florin MUNTEANU

    2009-09-01

    Full Text Available The 1.2 m x 1.2 m Trisonic Blowdown Wind Tunnel is the largest of the experimental facilities at the National Institute for Aerospace Research - I.N.C.A.S. "Elie Carafoli", Bucharest, Romania. The tunnel has been designed by the Canadian company DSMA (now AIOLOS and since its commissioning in 1978 has performed high speed aerodynamic tests for more than 120 projects of aircraft, missiles and other objects among which the twin jet fighter IAR-93, the jet trainer IAR-99, the MIG-21 Lancer, the Polish jet fighter YRYDA and others. In the last years the wind tunnel has been used mostly for experimental research in European projects such as UFAST. The high flow quality parameters and the wide range of testing capabilities ensure the competitivity of the tunnel at an international level.

  1. The ISI Tunnel

    Science.gov (United States)

    1993-10-01

    DP /etc/tunnelvisa p zephyr dark -star TCP /etc/tunnelvisa p zephyr dak’star ICMP /etc/tunnelvisa p zephyr quark MDP /etc/tunnelvisa p zephyr quark ...drax-net-yp 128.9.32.2 1 route add quark -net-yp 128.9.32.3 1 route add vlsi-net-yp 128.9.32.4 1 route add darkstar-net-yp 128.9.32.3 1 route add rocky...TCP /etc/tunnel-visa p zephyr quark ICMP /etc/tunnel-visa p zephyr drax tTI)P /etc/tunnel-visa p zephyr drax TCP /etc/tunnel_visa p zephyr drax ICMP

  2. Wind Tunnel Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This ARDEC facility consists of subsonic, transonic, and supersonic wind tunnels to acquire aerodynamic data. Full-scale and sub-scale models of munitions are fitted...

  3. Water Tunnel Facility

    Data.gov (United States)

    Federal Laboratory Consortium — NETL’s High-Pressure Water Tunnel Facility in Pittsburgh, PA, re-creates the conditions found 3,000 meters beneath the ocean’s surface, allowing scientists to study...

  4. Tunneling behavior of the formosan subterranean termite (isoptera: rhinotermitadae) in dry soil

    Science.gov (United States)

    This study examines the effect of dry soil on tunnel construction by the Formosan subterranean termite, Cptotermes formosanus. Termites did not construct tunnels in dry soil in any of the treatments. Termites only constructed tunnels in moist areas in treatments where the soil was partially moistene...

  5. The Beginner's Guide to Wind Tunnels with TunnelSim and TunnelSys

    Science.gov (United States)

    Benson, Thomas J.; Galica, Carol A.; Vila, Anthony J.

    2010-01-01

    The Beginner's Guide to Wind Tunnels is a Web-based, on-line textbook that explains and demonstrates the history, physics, and mathematics involved with wind tunnels and wind tunnel testing. The Web site contains several interactive computer programs to demonstrate scientific principles. TunnelSim is an interactive, educational computer program that demonstrates basic wind tunnel design and operation. TunnelSim is a Java (Sun Microsystems Inc.) applet that solves the continuity and Bernoulli equations to determine the velocity and pressure throughout a tunnel design. TunnelSys is a group of Java applications that mimic wind tunnel testing techniques. Using TunnelSys, a team of students designs, tests, and post-processes the data for a virtual, low speed, and aircraft wing.

  6. Quantum tunneling beyond semiclassical approximation

    International Nuclear Information System (INIS)

    Banerjee, Rabin; Majhi, Bibhas Ranjan

    2008-01-01

    Hawking radiation as tunneling by Hamilton-Jacobi method beyond semiclassical approximation is analysed. We compute all quantum corrections in the single particle action revealing that these are proportional to the usual semiclassical contribution. We show that a simple choice of the proportionality constants reproduces the one loop back reaction effect in the spacetime, found by conformal field theory methods, which modifies the Hawking temperature of the black hole. Using the law of black hole mechanics we give the corrections to the Bekenstein-Hawking area law following from the modified Hawking temperature. Some examples are explicitly worked out.

  7. RITD – Wind tunnel testing

    Science.gov (United States)

    Haukka, Harri; Harri, Ari-Matti; Aleksashkin, Sergei; Koryanov, Valeri; Schmidt, Walter; Heilimo, Jyri; Finchenko, Valeri; Martynov, Maxim; Ponomarenko, Andrey; Kazakovtsev, Victor; Arruego, Ignazio

    2015-04-01

    An atmospheric re-entry and descent and landing system (EDLS) concept based on inflatable hypersonic decelerator techniques is highly promising for the Earth re-entry missions. We developed such EDLS for the Earth re-entry utilizing a concept that was originally developed for Mars. This EU-funded project is called RITD - Re-entry: Inflatable Technology Development - and it was to assess the bene¬fits of this technology when deploying small payloads from low Earth orbits to the surface of the Earth with modest costs. The principal goal was to assess and develope a preliminary EDLS design for the entire relevant range of aerodynamic regimes expected to be encountered in Earth's atmosphere during entry, descent and landing. The RITD entry and descent system utilizes an inflatable hypersonic decelerator. Development of such system requires a combination of wind tunnel tests and numerical simulations. This included wind tunnel tests both in transsonic and subsonic regimes. The principal aim of the wind tunnel tests was the determination of the RITD damping factors in the Earth atmosphere and recalculation of the results for the case of the vehicle descent in the Mars atmosphere. The RITD mock-up model used in the tests was in scale of 1:15 of the real-size vehicle as the dimensions were (midsection) diameter of 74.2 mm and length of 42 mm. For wind tunnel testing purposes the frontal part of the mock-up model body was manufactured by using a PolyJet 3D printing technology based on the light curing of liquid resin. The tail part of the mock-up model body was manufactured of M1 grade copper. The structure of the mock-up model placed th center of gravity in the same position as that of the real-size RITD. The wind tunnel test program included the defining of the damping factor at seven values of Mach numbers 0.85; 0.95; 1.10; 1.20; 1.25; 1.30 and 1.55 with the angle of attack ranging from 0 degree to 40 degrees with the step of 5 degrees. The damping characteristics of

  8. Tunnelling of a molecule

    International Nuclear Information System (INIS)

    Jarvis, P.D.; Bulte, D.P.

    1998-01-01

    A quantum-mechanical description of tunnelling is presented for a one-dimensional system with internal oscillator degrees of freedom. The 'charged diatomic molecule' is frustrated on encountering a barrier potential by its centre of charge not being coincident with its centre of mass, resulting in transitions amongst internal states. In an adiabatic limit, the tunnelling of semiclassical coherent-like oscillator states is shown to exhibit the Hartman and Bueuttiker-Landauer times t H and t BL , with the time dependence of the coherent state parameter for the tunnelled state given by α(t) = α e -iω(t+Δt) , Δt = t H - it BL . A perturbation formalism is developed, whereby the exact transfer matrix can be expanded to any desired accuracy in a suitable limit. An 'intrinsic' time, based on the oscillator transition rate during tunnelling, transmission or reflection, is introduced. In simple situations the resulting intrinsic tunnelling time is shown to vanish to lowest order. In the general case a particular (nonzero) parametrisation is inferred, and its properties discussed in comparison with the literature on tunnelling times for both wavepackets and internal clocks. Copyright (1998) CSIRO Australia

  9. Experience in design and construction of the Log tunnel

    Directory of Open Access Journals (Sweden)

    Jovičić Vojkan

    2017-09-01

    Full Text Available A twin highway Log tunnel is a part of a new motorway connection between Maribor and Zagreb, section Draženci-Gruškovje, which is located towards the border crossing between Slovenia and Croatia. The tunnel is currently under construction, and only the excavation works have been completed during the writing of this paper. The terrain in the area of the Log tunnel is diverse, and the route of the highway in its vicinity is characterised by deep excavations, bridges or viaducts. The Log tunnel is approximately 250 m long, partly constructed as a gallery. The geological conditions are dominated by Miocene base rock, featuring layers of well-connected clastic rocks, which are covered by diluvium clays, silts, sands and gravels of different thicknesses. Due to the short length of the tunnel, the usual separation of the motorway route to the left and the right tunnel axes was not carried out. Thus, the tunnel was constructed with an intermediate pillar and was designed as a three-lane tunnel, including the stopping lane. The construction of the tunnel was carried out using the New Austrian tunnelling method (NATM, in which the central adit was excavated first and the intermediate pillar was constructed within it. The excavation of the main tubes followed and was divided into the top heading, bench and the invert, enabling the intermediate pillar to take the load off the top heading of both tubes. The secondary lining of the tunnel is currently under construction. The experience of the tunnel construction gathered so far is presented in the paper. The main emphasis is on the construction of the intermediate pillar, which had to take the significant and asymmetrical ground load.

  10. Experience in design and construction of the Log tunnel

    Science.gov (United States)

    Jovičić, Vojkan; Goleš, Niko; Tori, Matija; Peternel, Miha; Vajović, Stanojle; Muhić, Elvir

    2017-09-01

    A twin highway Log tunnel is a part of a new motorway connection between Maribor and Zagreb, section Draženci-Gru\\vskovje, which is located towards the border crossing between Slovenia and Croatia. The tunnel is currently under construction, and only the excavation works have been completed during the writing of this paper. The terrain in the area of the Log tunnel is diverse, and the route of the highway in its vicinity is characterised by deep excavations, bridges or viaducts. The Log tunnel is approximately 250 m long, partly constructed as a gallery. The geological conditions are dominated by Miocene base rock, featuring layers of well-connected clastic rocks, which are covered by diluvium clays, silts, sands and gravels of different thicknesses. Due to the short length of the tunnel, the usual separation of the motorway route to the left and the right tunnel axes was not carried out. Thus, the tunnel was constructed with an intermediate pillar and was designed as a three-lane tunnel, including the stopping lane. The construction of the tunnel was carried out using the New Austrian tunnelling method (NATM), in which the central adit was excavated first and the intermediate pillar was constructed within it. The excavation of the main tubes followed and was divided into the top heading, bench and the invert, enabling the intermediate pillar to take the load off the top heading of both tubes. The secondary lining of the tunnel is currently under construction. The experience of the tunnel construction gathered so far is presented in the paper. The main emphasis is on the construction of the intermediate pillar, which had to take the significant and asymmetrical ground load.

  11. OPTIMAL PARAMETERS OF BLASTING IN TUNNELS USING PATRONED AND PUMPED EXPLOSIVES WITH ELECTRIC AND NON-ELECTRIC INITIATION

    Directory of Open Access Journals (Sweden)

    Zvonimir Deković

    2003-12-01

    Full Text Available The parameters of drilling and blasting procedures during excavation of Grič and mala Kapela Tunnels are presented in this work. The tunnels are being constructed according to NATM (New Austrian Tunneling Method in two parallel tubes. By Comparison of blasting with patroned and pumped explosives and electric and non-electric mode of initiation, optimal technological parameters have been defined concerning duration of blasting working cycle, progress, tunnel category and seismic effects of blasting on the tunnel support system of the parallel tunnel tube.

  12. Fire analyses in central and disposal tunnels by APROS

    International Nuclear Information System (INIS)

    Peltokorpi, L.; Kukkola, T.; Nieminen, J.

    2012-12-01

    The central tunnels and the disposal tunnels on the north-east disposal area are the target areas of the fire studies. Target is to maintain under pressure in the fire zone in case of a fire. In the central tunnels a fire of a drilling jumbo with moderate fire propagation is used as heat release rate. In the disposal tunnel the heat release rate of a canister transfer and installation vehicle fire received as a result of the pyrolysis analyze as well as an average heat release rate of a van fire are used. Inlet air is to be conducted to the back end of the fire zone and the exhaust is to be lead out from the beginning of the fire zone. The worst location of the fire is in the beginning of the fire zone just below of the exhaust air clap valve. The size of the fire zone does not have big impact on pressure. In all analyzed cases the fire zone remains too long time over pressurized. Inlet air flow of a 30 m 3 /s is too much. The rotation controlled booster blowers will solve the pressure problems of the fire zone in fire cases. The rotation is controlled by the fire zone pressure. The fire of the canister transfer and installation vehicle in the central tunnel will not cause problems. The disposal tunnel fire door should be kept open, if the canister transfer and installation vehicle or the bentonite blocks transfer and installation vehicle is driven into the disposal tunnel. If a fire is caught in the disposal tunnel then the fire zone in the central tunnel is to be closed and the pressure is controlled by the rotation controlled booster blowers. If a personnel car or a van is driven into the disposal tunnel, then fire door of the disposal is to be kept closed against fires in the central tunnel. (orig.)

  13. Data Quality Objectives Report for the 115-B Gas Tunnel

    International Nuclear Information System (INIS)

    Bauer, R.G.

    1998-05-01

    This workbook assisted the Data Quality Objectives Team in implementing the Data Quality Objectives Process through the use of a template which lists the important elements of the DQO. The completion of this workbook is a required element of the BHI-EE-01, Procedure 1.2, 'Data Quality Objectives.' The objective of this project is to define the sampling and analysis requirements for isolation and decontamination and decommissioning release of the 115- B Gas Tunnel. The 115-B Gas Tunnel is an underground concrete pipe tunnel that houses piping used to recirculate helium gas between the 105-B Reactor Building and the 115-B/C Gas Recirculation System

  14. Defining cyber warfare

    Directory of Open Access Journals (Sweden)

    Dragan D. Mladenović

    2012-04-01

    Full Text Available Cyber conflicts represent a new kind of warfare that is technologically developing very rapidly. Such development results in more frequent and more intensive cyber attacks undertaken by states against adversary targets, with a wide range of diverse operations, from information operations to physical destruction of targets. Nevertheless, cyber warfare is waged through the application of the same means, techniques and methods as those used in cyber criminal, terrorism and intelligence activities. Moreover, it has a very specific nature that enables states to covertly initiate attacks against their adversaries. The starting point in defining doctrines, procedures and standards in the area of cyber warfare is determining its true nature. In this paper, a contribution to this effort was made through the analysis of the existing state doctrines and international practice in the area of cyber warfare towards the determination of its nationally acceptable definition.

  15. Rock mass characterization for tunnels in the Copenhagen limestone

    DEFF Research Database (Denmark)

    Foged, Niels Nielsen; Jakobsen, Lisa; Jackson, Peter

    2007-01-01

    Tunnels in Copenhagen are drilled through highly anisotropic limestone comprising alternating strongly lithified and less lithified parts. The mass quality of the limestone is usually defined from fracture spacing registered in core samples. The deposit is, however, affected destructively by dril...... by drilling activity yielding a low Rock Quality Designation RQD. In-situ observations of the limestone in excavations or televiewer logs reveal only few natural discontinuities compared to core logging, indicating a very good suitability for tunneling....

  16. Independent directors’ board networks and controlling shareholders’ tunneling behavior

    OpenAIRE

    Chen, Yunsen; Wang, Yutao; Lin, Le

    2014-01-01

    As one of the channels by which board directors build important relationships, board networks can affect the governance role of independent directors. Defining director board networks as their connections based on direct ties they establish when serving on at least one common board, this paper explores the role of the network centrality of independent directors in restraining tunneling behavior by controlling shareholders in the Chinese capital market. Our empirical evidence shows that tunnel...

  17. Resonant tunnel magnetoresistance in a double magnetic tunnel junction

    KAUST Repository

    Useinov, Arthur; Useinov, Niazbeck Kh H; Tagirov, Lenar R.; Kosel, Jü rgen

    2011-01-01

    We present quasi-classical approach to calculate a spin-dependent current and tunnel magnetoresistance (TMR) in double magnetic tunnel junctions (DMTJ) FML/I/FMW/I/FMR, where the magnetization of the middle ferromagnetic metal layer FMW can

  18. Seepage into PEP tunnel

    International Nuclear Information System (INIS)

    Weidner, H.

    1990-01-01

    The current rate of seepage into the PEP tunnel in the vicinity of IR-10 is very low compared to previous years. Adequate means of handling this low flow are in place. It is not clear whether the reduction in the flow is temporary, perhaps due to three consecutive dry years, or permanent due to drainage of a perched water table. During PEP construction a large amount of effort was expended in attempts to seal the tunnel, with no immediate effect. The efforts to ''manage'' the water flow are deemed to be successful. By covering equipment to protect it from dripping water and channeling seepage into the drainage gutters, the seepage has been reduced to a tolerable nuisance. There is no sure, safe procedure for sealing a leaky shotcreted tunnel

  19. Uncooled tunneling infrared sensor

    Science.gov (United States)

    Kenny, Thomas W. (Inventor); Kaiser, William J. (Inventor); Podosek, Judith A. (Inventor); Vote, Erika C. (Inventor); Muller, Richard E. (Inventor); Maker, Paul D. (Inventor)

    1995-01-01

    An uncooled infrared tunneling sensor in which the only moving part is a diaphragm which is deflected into contact with a micromachined silicon tip electrode prepared by a novel lithographic process. Similarly prepared deflection electrodes employ electrostatic force to control the deflection of a silicon nitride, flat diaphragm membrane. The diaphragm exhibits a high resonant frequency which reduces the sensor's sensitivity to vibration. A high bandwidth feedback circuit controls the tunneling current by adjusting the deflection voltage to maintain a constant deflection of the membrane. The resulting infrared sensor can be miniaturized to pixel dimensions smaller than 100 .mu.m. An alternative embodiment is implemented using a corrugated membrane to permit large deflection without complicated clamping and high deflection voltages. The alternative embodiment also employs a pinhole aperture in a membrane to accommodate environmental temperature variation and a sealed chamber to eliminate environmental contamination of the tunneling electrodes and undesireable accoustic coupling to the sensor.

  20. Instabilities in thin tunnel junctions

    International Nuclear Information System (INIS)

    Konkin, M.K.; Adler, J.G.

    1978-01-01

    Tunnel junctions prepared for inelastic electron tunneling spectroscopy are often plagued by instabilities in the 0-500-meV range. This paper relates the bias at which the instability occurs to the barrier thickness

  1. Environmental Impact Assessment, Brownfield Areas. Brownfields are defined by the Florida DEP as abandoned, idled, or underused industrial and commercial facilities where expansion or redevelopment is complicated by real or perceived environmental contamination., Published in 2001, 1:24000 (1in=2000ft) scale, Florida Department of Environmental Protection (FDEP).

    Data.gov (United States)

    NSGIC State | GIS Inventory — Environmental Impact Assessment dataset current as of 2001. Brownfield Areas. Brownfields are defined by the Florida DEP as abandoned, idled, or underused industrial...

  2. Presentation of Austrians recommended dispersion model for tunnel portals

    Energy Technology Data Exchange (ETDEWEB)

    Oettl, D.; Sturm, P.; Almbauer, R. [Inst. for Internal Combustion Engines and Thermodynamics, Graz Univ. of Technology (Austria)

    2004-07-01

    Street tunnels in cities are often suggested as solution to avoid daily congestions but also to prevent residential areas from high noise and air pollution emissions. In case of longitudinal ventilated tunnels high pollution levels may occur in the vicinity of the portals. The dispersion of pollutants from tunnel portals is considered to differ significantly from those of other sources, such as line or point sources. To the best of the authors knowledge, there exist currently two distinct dispersion models, which are especially designed to treat dispersion from tunnel portals. Okamoto et al proposed a diagnostic wind field model, where the dispersion is modelled using a Taylor-Galerkin-Forester filter method. Oettl et al. developed a Lagrangian-type model (GRAL TM 3.5=Graz Lagrangian model Tunnel Module version 3.5), which is briefly described in the next section. (orig.)

  3. Tunneling in axion monodromy

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Jon; Cottrell, William; Shiu, Gary; Soler, Pablo [Department of Physics, University of Wisconsin,Madison, WI 53706 (United States)

    2016-10-06

    The Coleman formula for vacuum decay and bubble nucleation has been used to estimate the tunneling rate in models of axion monodromy in recent literature. However, several of Coleman’s original assumptions do not hold for such models. Here we derive a new estimate with this in mind using a similar Euclidean procedure. We find that there are significant regions of parameter space for which the tunneling rate in axion monodromy is not well approximated by the Coleman formula. However, there is also a regime relevant to large field inflation in which both estimates parametrically agree. We also briefly comment on the applications of our results to the relaxion scenario.

  4. LEP tunnel monorail

    CERN Multimedia

    1985-01-01

    A monorail from CERN's Large Electron Positron collider (LEP, for short). It ran around the 27km tunnel, transporting equipment and personnel. With its 27-kilometre circumference, LEP was the largest electron-positron accelerator ever built and ran from 1989 to 2000. During 11 years of research, LEP's experiments provided a detailed study of the electroweak interaction. Measurements performed at LEP also proved that there are three – and only three – generations of particles of matter. LEP was closed down on 2 November 2000 to make way for the construction of the Large Hadron Collider in the same tunnel.

  5. Excavating a transfer tunnel

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    The transfer tunnel being dug here will take the 450 GeV beam from the SPS and inject it into the LHC where the beam energies will be increased to 7 TeV. In order to transfer this beam from the SPS to the LHC, two transfer tunnels are used to circulate the beams in opposite directions. When excavated, the accelerator components, including magnets, beam pipes and cryogenics will be installed and connected to both the SPS and LHC ready for operation to begin in 2008.

  6. Gap anisotropy and tunneling currents. [MPS3

    DEFF Research Database (Denmark)

    Lazarides, N.; Sørensen, Mads Peter

    1996-01-01

    The tunneling Hamiltonian formalism is applied to calculate the tunnelingcurrents through a small superconducting tunnel junction. The formalism isextended to nonconstant tunneling matrix elements. The electrodes of thejunction are assumed to......The tunneling Hamiltonian formalism is applied to calculate the tunnelingcurrents through a small superconducting tunnel junction. The formalism isextended to nonconstant tunneling matrix elements. The electrodes of thejunction are assumed to...

  7. Breaking through the tranfer tunnel

    CERN Document Server

    Laurent Guiraud

    2001-01-01

    This image shows the tunnel boring machine breaking through the transfer tunnel into the LHC tunnel. Proton beams will be transferred from the SPS pre-accelerator to the LHC at 450 GeV through two specially constructed transfer tunnels. From left to right: LHC Project Director, Lyn Evans; CERN Director-General (at the time), Luciano Maiani, and Director for Accelerators, Kurt Hubner.

  8. Control of tunneling in heterostructures

    International Nuclear Information System (INIS)

    Volokhov, V M; Tovstun, C A; Ivlev, B

    2007-01-01

    A tunneling current between two rectangular potential wells can be effectively controlled by applying an external ac field. A variation of the ac frequency by 10% may lead to the suppression of the tunneling current by two orders of magnitude, which is a result of quantum interference under the action of the ac field. This effect of destruction of tunneling can be used as a sensitive control of tunneling current across nanosize heterostructures

  9. Geometrical and mechanical properties of the fractures and brittle deformation zones based on the ONKALO tunnel mapping, 2400 - 4390 m tunnel chainage

    Energy Technology Data Exchange (ETDEWEB)

    Moenkkoenen, H.; Rantanen, T.; Kuula, H. [WSP Finland Oy, Helsinki (Finland)

    2012-05-15

    In this report, the rock mechanics parameters of fractures and brittle deformation zones have been estimated in the vicinity of the ONKALO area at the Olkiluoto site, western Finland. This report is an extension of the previously published report: Geometrical and Mechanical properties if the fractures and brittle deformation zones based on ONKALO tunnel mapping, 0-2400 m tunnel chainage (Kuula 2010). In this updated report, mapping data are from 2400-4390 m tunnel chainage. Defined rock mechanics parameters of the fractures are associated with the rock engineering classification quality index, Q', which incorporates the RQD, Jn, Jr and Ja values. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers. There are no new data from laboratory joint shear and normal tests. The fracture wall compressive strength (JCS) data are available from the chainage range 1280-2400 m. Estimation of the mechanics properties of the 24 brittle deformation zones (BDZ) is based on the mapped Q' value, which is transformed to the GSI value in order to estimate strength and deformability properties. A component of the mapped Q' values is from the ONKALO and another component is from the drill cores. In this study, 24 BDZs have been parameterized. The location and size of the brittle deformation are based on the latest interpretation. New data for intact rock strength of the brittle deformation zones are not available. (orig.)

  10. Ivar Giaever, Tunneling, and Superconductors

    Science.gov (United States)

    dropdown arrow Site Map A-Z Index Menu Synopsis Ivar Giaever, Tunneling, and Superconductors Resources with in Superconductors Measured by Electron Tunneling; Physical Review Letters, Vol. 5 Issue 4: 147 - 148 ; August 15, 1960 Electron Tunneling Between Two Superconductors; Physical Review Letters, Vol. 5 Issue 10

  11. Physics of optimal resonant tunneling

    NARCIS (Netherlands)

    Racec, P.N.; Stoica, T.; Popescu, C.; Lepsa, M.I.; Roer, van de T.G.

    1997-01-01

    The optimal resonant tunneling, or the complete tunneling transparence of a biased double-barrier resonant-tunneling (DBRT) structure, is discussed. It is shown that its physics does not rest on the departure from the constant potential within the barriers and well, due to the applied electric

  12. The etiology of idiopathic carpal tunnel syndrome. Evaluation from the viewpoint of magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ikeda, Jun

    2003-01-01

    The etiology of idiopathic carpal tunnel syndrome has not been clarified. A cross sectional area of carpal tunnel, flexor tendons, median nerve, and thickness of transverse carpal ligament were evaluated by MRI. Twenty-six patients who were electrophysiologically diagnosed with idiopathic carpal tunnel syndrome were tested by MRI. All patients were females; the mean age was sixty-four years old. The cross sectional area of carpal tunnel, the median nerve area, the area of the flexor tendons and its synovium in carpal tunnel, and thickness of the transverse carpal ligament were calculated. The following are of a seuere type carpal tunnel syndrome: Mean area of the flexor tendons and its synovium in carpal tunnel, 110.5±25.5 mm 2 (control group; 79.3±13.8 mm 2 ); ratio of flexor tendons and its synovium area to carpal tunnel area, 51.6±8.8% (control; 40.5±2.3%); and thickness of the transverse carpal ligament, 3.3±0.4 mm (control; 2.4±0.4 mm). These mean areas in severe carpal tunnel syndrome were significantly greater than those in mild type (p<0.05 or p<0.01). From the viewpoint of this result, it is possible that tenosynovitis is strongly to the etiology of idiopathic carpal tunnel syndrome. In other words, synovium edema causes chronic high pressure environment in carpal tunnel. Moreover, we classified these MRI findings into the following subgroups: enlargement of cross sectional area of flexor tendon and its synovia (n=8; 25.8%), thickened transverse carpal ligament (n=11; 35.5%), and combined type (n=7; 22.6%). This classification by MRI imaging was related to a clinical course and electro-physiologic severity. The present study suggests that to evaluate the cross sectional, area of an MRI image is useful for diagnosis and cure of idiopathic carpal tunnel syndrome. (author)

  13. Landslide Cause Analysis of the K0+200 Area in a Tunnel of Hanjiang River to the Weihe River ProjectⅡ%引汉济渭二期工程某隧洞0+200塌方原因分析

    Institute of Scientific and Technical Information of China (English)

    蒋锐; 焦振华

    2016-01-01

    One tunnel of Hanjiang River to the Weihe River Project Phase II occurred landslide , so construction unit questioned whether the collapse section can be treated and follow-up of the tunnel can continue to be dug or not .Based on the consideration of collapse and the geological conditions of the collapse area ,this article analyses the causes of land-slides.Therefore,it obtains the conclusion that the treatment of landslide area can be carried out .So,the tunnel can con-tinue to be dug through the method of strengthening the support and protection .%引汉济渭二期工程某隧洞出现塌方现象,施工单位对塌方段能否处理和后续隧洞能否继续开挖提出异议,分析塌方现象、塌方段洞室附近地质条件及塌方原因,得出对塌方工程处理是可行的,后续隧洞加强支护是可以成洞的结论。

  14. Mechanical stability of repository tunnels and factors to be considered for determining tunnel spacing

    International Nuclear Information System (INIS)

    Takeuchi, Kunifumi

    1994-01-01

    Kristallin-1 organized by Nagra is currently advanced as a synthetic project regarding a high level radioactive waste (HLW) repository in Switzerland. Its host rock is granitic rocks, and the potential siting area is located in northern Switzerland. The objective of this project is to demonstrate the long term safety of a HLW repository under more site-specific conditions than before. As the detailed geological data were investigated, the average size of undisturbed crystalline rock blocks is limited horizontally to about several hundred meter, therefore, the HLW repository area must be divided into several panels to avoid fracture zones. It is necessary to make tunnel spacing as small as possible for the purpose of reasonably designing the entire layout of repository tunnels. The main factors to be considered for determining repository tunnel spacing are listed. Rock mass modeling, rock mass material properties, the analysis model and parameters, the numerical analysis of repository tunnel stability and its main conclusion are reported. The numerical analysis of the temperature distribution in near field was carried out. Tunnel spacing should be set more than 20 m in view of the maximum temperature. (K.I.)

  15. Magnetic Fluxtube Tunneling

    Science.gov (United States)

    Dahlburg, Russell B.; Antiochos,, Spiro K.; Norton, D.

    1996-01-01

    We present numerical simulations of the collision and subsequent interaction of two initially orthogonal, twisted, force free field magnetic fluxtubes. The simulations were carried out using a new three dimensional explicit parallelized Fourier collocation algorithm for solving the viscoresistive equations of compressible magnetohydrodynamics. It is found that, under a wide range of conditions, the fluxtubes can 'tunnel' through each other. Two key conditions must be satisfied for tunneling to occur: the magnetic field must be highly twisted with a field line pitch much greater than 1, and the magnetic Lundquist number must be somewhat large, greater than or equal to 2880. This tunneling behavior has not been seen previously in studies of either vortex tube or magnetic fluxtube interactions. An examination of magnetic field lines shows that tunneling is due to a double reconnection mechanism. Initially orthogonal field lines reconnect at two specific locations, exchange interacting sections and 'pass' through each other. The implications of these results for solar and space plasmas are discussed.

  16. Tunnel nitrogen spill experiment

    International Nuclear Information System (INIS)

    Ageyev, A.I.; Alferov, V.N.; Mulholland, G.T.

    1983-01-01

    The Energy Saver Safety Analysis Report (SAR) found the tunnel oxygen deficiency considerations emphasized helium spills. These reports concluded the helium quickly warms and because of its low denisty, rises to the apex of the tunnel. The oxygen content below the apex and in all but the immediate vicinity of the helium spill is essentially unchanged and guarantees an undisturbed source of oxygen especially important to fallen personnel. In contrast nitrogen spills warm slower than helium due to the ratio of the enthalpy changes per unit volume spilled spread more uniformly across the tunnel cross-section when warmed because of the much smaller density difference with air, and generally provides a greater hazard than helium spills as a result. In particular there was concern that personnel that might fall to the floor for oxygen deficiency or other reasons might find less, and not more, oxygen with dire consequences. The SAR concluded tunnel nitrogen spills were under-investigated and led to this work

  17. The scanning tunneling microscope

    International Nuclear Information System (INIS)

    Salvan, F.

    1986-01-01

    A newly conceived microscope, based on a pure quantum phenomenon, is an ideal tool to study atom by atom the topography and properties of surfaces. Applications are presented: surface ''reconstruction'' of silicon, lamellar compound study, etc... Spectroscopy by tunnel effect will bring important information on electronic properties; it is presented with an application on silicon [fr

  18. On Defining Mass

    Science.gov (United States)

    Hecht, Eugene

    2011-01-01

    Though central to any pedagogical development of physics, the concept of mass is still not well understood. Properly defining mass has proven to be far more daunting than contemporary textbooks would have us believe. And yet today the origin of mass is one of the most aggressively pursued areas of research in all of physics. Much of the excitement surrounding the Large Hadron Collider at CERN is associated with discovering the mechanism responsible for the masses of the elementary particles. This paper will first briefly examine the leading definitions, pointing out their shortcomings. Then, utilizing relativity theory, it will propose—for consideration by the community of physicists—a conceptual definition of mass predicated on the more fundamental concept of energy, more fundamental in that everything that has mass has energy, yet not everything that has energy has mass.

  19. Coupled Boundary and Finite Element Analysis of Vibration from Railway Tunnels

    DEFF Research Database (Denmark)

    Andersen, Lars; Jones, C.J.C.

    2006-01-01

    The analysis of vibration from railway tunnels is of growing interest as new and higher-speed railways are built under the ground to address the transport problems of growing modern urban areas around cities. Such analysis can be carried out using numerical methods but models and therefore comput...... body vibration (about 4 to 80 Hz). A coupled finite element and boundary element scheme is applied in both two and three dimensions. Two tunnel designs are considered: a cut-and-cover tunnel for a double track and a single-track tunnel dug with the New Austrian Tunnelling Method (NATM)....

  20. Monitoring pilot projects on bored tunnelling : The Second Heinenoord Tunnel and the Botlek Rail Tunnel

    NARCIS (Netherlands)

    Bakker, K.J.; De Boer, F.; Admiraal, J.B.M.; Van Jaarsveld, E.P.

    1999-01-01

    Two pilot projects for bored tunnelling in soft soil have been undertaken in the Netherlands. The monitoring was commissioned under the authority of the Centre for Underground Construction (COB). A description of the research related to the Second Heinenoord Tunnel and the Botlek Rail Tunnel will be

  1. Measuring fire size in tunnels

    International Nuclear Information System (INIS)

    Guo, Xiaoping; Zhang, Qihui

    2013-01-01

    A new measure of fire size Q′ has been introduced in longitudinally ventilated tunnel as the ratio of flame height to the height of tunnel. The analysis in this article has shown that Q′ controls both the critical velocity and the maximum ceiling temperature in the tunnel. Before the fire flame reaches tunnel ceiling (Q′ 1.0), Fr approaches a constant value. This is also a well-known phenomenon in large tunnel fires. Tunnel ceiling temperature shows the opposite trend. Before the fire flame reaches the ceiling, it increases very slowly with the fire size. Once the flame has hit the ceiling of tunnel, temperature rises rapidly with Q′. The good agreement between the current prediction and three different sets of experimental data has demonstrated that the theory has correctly modelled the relation among the heat release rate of fire, ventilation flow and the height of tunnel. From design point of view, the theoretical maximum of critical velocity for a given tunnel can help to prevent oversized ventilation system. -- Highlights: • Fire sizing is an important safety measure in tunnel design. • New measure of fire size a function of HRR of fire, tunnel height and ventilation. • The measure can identify large and small fires. • The characteristics of different fire are consistent with observation in real fires

  2. Calculation of cut-off values based on the Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) and Pemphigus Disease Area Index (PDAI) pemphigus scoring systems for defining moderate, significant and extensive types of pemphigus.

    Science.gov (United States)

    Boulard, C; Duvert Lehembre, S; Picard-Dahan, C; Kern, J S; Zambruno, G; Feliciani, C; Marinovic, B; Vabres, P; Borradori, L; Prost-Squarcioni, C; Labeille, B; Richard, M A; Ingen-Housz-Oro, S; Houivet, E; Werth, V P; Murrell, D F; Hertl, M; Benichou, J; Joly, P

    2016-07-01

    Two pemphigus severity scores, Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) and Pemphigus Disease Area Index (PDAI), have been proposed to provide an objective measure of disease activity. However, the use of these scores in clinical practice is limited by the absence of cut-off values that allow differentiation between moderate, significant and extensive types of pemphigus. To calculate cut-off values defining moderate, significant and extensive pemphigus based on the ABSIS and PDAI scores. In 31 dermatology departments in six countries, consecutive patients with newly diagnosed pemphigus were assessed for pemphigus severity, using ABSIS, PDAI, Physician's Global Assessment (PGA) and Dermatology Life Quality Index (DLQI) scores. Cut-off values defining moderate, significant and extensive subgroups were calculated based on the 25th and 75th percentiles of the ABSIS and PDAI scores. The median ABSIS, PDAI, PGA and DLQI scores of the three severity subgroups were compared in order to validate these subgroups. Ninety-six patients with pemphigus vulgaris (n = 77) or pemphigus foliaceus (n = 19) were included. The median PDAI activity and ABSIS total scores were 27·5 (range 3-84) and 34·8 points (range 0·5-90·5), respectively. The respective cut-off values corresponding to the first and third quartiles of the scores were 15 and 45 for the PDAI, and 17 and 53 for ABSIS. The moderate, significant and extensive subgroups were thus defined, and had distinguishing median ABSIS (P cut-off values of 15 and 45 for PDAI and 17 and 53 for ABSIS, to distinguish moderate, significant and extensive pemphigus forms. Identifying these pemphigus activity subgroups should help physicians to classify and manage patients with pemphigus. © 2016 British Association of Dermatologists.

  3. Ultrasonographic median nerve cross-section areas measured by 8-point 'inching test' for idiopathic carpal tunnel syndrome: a correlation of nerve conduction study severity and duration of clinical symptoms

    International Nuclear Information System (INIS)

    Chen, Shu-Fang; Lu, Cheng-Hsien; Huang, Chi-Ren; Chuang, Yao-Chung; Tsai, Nai-Wen; Chang, Chiung-Chih; Chang, Wen-Neng

    2011-01-01

    Incremental palmar stimulation of the median nerve sensory conduction at the wrist, the 'inching test', provides an assessment with reference to segments proximal and distal to the entrapment. This study used high-resolution ultrasonography (US) to measure the median nerve's cross-section areas (CSAs) like the 'inching test' and to correlate with the nerve conduction study (NCS) severity and duration of carpal tunnel syndrome (CTS). Two hundred and twelve (212) 'CTS-hands' from 135 CTS patients and 50 asymptomatic hands ('A-hands') from 25 control individuals were enrolled. The median nerve CSAs were measured at the 8-point marked as i4, i3, i2, i1, w, o1, o2, and 03 in inching test. The NCS severities were classified into six groups based on motor and sensory responses (i.e., negative, minimal, mild, moderate, severe, and extreme). Results of US studies were compared in terms of NCS severity and duration of clinical CTS symptoms. There was significantly larger CSA of the NCS negative group of 'CTS-hands' than of 'A-hands'. The cut-off values of the CSAs of the NCS negative CTS group were 12.5 mm 2 , 11.5 mm 2 and 10.1 mm 2 at the inlet, wrist crease, and outlet, respectively. Of the 212 'CTS-hands', 32 were NCS negative while 40 had minimal, 43 mild, 85 moderate, 10 severe, and two extreme NCS severities. The CSAs of 'CTS-hands' positively correlated with different NCS severities and with the duration of CTS symptoms. By duration of clinical symptoms, 12 of the 212 'CTS-hands' were in the 1 month group; 82 in >1 month and ≤12 months group, and 118 in >12 months group. In 'inching test', segments i4-i3 and i3-i2 were the most common 'positive-site'. The corresponding CSAs measured at i4 and i3, but not at i2, were significantly larger than those measured at points that were not 'positive-site'. Using the 8-point measurement of the median

  4. Magnetic tunnel junction thermocouple for thermoelectric power harvesting

    Science.gov (United States)

    Böhnert, T.; Paz, E.; Ferreira, R.; Freitas, P. P.

    2018-05-01

    The thermoelectric power generated in magnetic tunnel junctions (MTJs) is determined as a function of the tunnel barrier thickness for a matched electric circuit. This study suggests that lower resistance area product and higher tunnel magnetoresistance will maximize the thermoelectric power output of the MTJ structures. Further, the thermoelectric behavior of a series of two MTJs, a MTJ thermocouple, is investigated as a function of its magnetic configurations. In an alternating magnetic configurations the thermovoltages cancel each other, while the magnetic contribution remains. A large array of MTJ thermocouples could amplify the magnetic thermovoltage signal significantly.

  5. Advanced Metrology for Characterization of Magnetic Tunnel Junctions

    DEFF Research Database (Denmark)

    Kjær, Daniel

    -plane tunneling (CIPT) for characterization of magnetic tunnel junctions (MTJs), which constitutes the key component not only in MRAM but also the read-heads of modern hard disk drives. MTJs are described by their tunnel magnetoresistance (TMR), which is the relative difference of the resistance area products (RA...... of this project has been to provide cheaper, faster and more precise metrology for MTJs. This goal has been achieved in part by the demonstration of a static field CIPT method, which allows us to reduce the measurement time by a factor of 5, by measuring only RA thus excluding TMR. This enhancement is obtained...

  6. Defining an emerging disease.

    Science.gov (United States)

    Moutou, F; Pastoret, P-P

    2015-04-01

    Defining an emerging disease is not straightforward, as there are several different types of disease emergence. For example, there can be a 'real' emergence of a brand new disease, such as the emergence of bovine spongiform encephalopathy in the 1980s, or a geographic emergence in an area not previously affected, such as the emergence of bluetongue in northern Europe in 2006. In addition, disease can emerge in species formerly not considered affected, e.g. the emergence of bovine tuberculosis in wildlife species since 2000 in France. There can also be an unexpected increase of disease incidence in a known area and a known species, or there may simply be an increase in our knowledge or awareness of a particular disease. What all these emerging diseases have in common is that human activity frequently has a role to play in their emergence. For example, bovine spongiform encephalopathy very probably emerged as a result of changes in the manufacturing of meat-and-bone meal, bluetongue was able to spread to cooler climes as a result of uncontrolled trade in animals, and a relaxation of screening and surveillance for bovine tuberculosis enabled the disease to re-emerge in areas that had been able to drastically reduce the number of cases. Globalisation and population growth will continue to affect the epidemiology of diseases in years to come and ecosystems will continue to evolve. Furthermore, new technologies such as metagenomics and high-throughput sequencing are identifying new microorganisms all the time. Change is the one constant, and diseases will continue to emerge, and we must consider the causes and different types of emergence as we deal with these diseases in the future.

  7. Convexity, gauge-dependence and tunneling rates

    Energy Technology Data Exchange (ETDEWEB)

    Plascencia, Alexis D.; Tamarit, Carlos [Institute for Particle Physics Phenomenology, Durham University,South Road, DH1 3LE (United Kingdom)

    2016-10-19

    We clarify issues of convexity, gauge-dependence and radiative corrections in relation to tunneling rates. Despite the gauge dependence of the effective action at zero and finite temperature, it is shown that tunneling and nucleation rates remain independent of the choice of gauge-fixing. Taking as a starting point the functional that defines the transition amplitude from a false vacuum onto itself, it is shown that decay rates are exactly determined by a non-convex, false vacuum effective action evaluated at an extremum. The latter can be viewed as a generalized bounce configuration, and gauge-independence follows from the appropriate Nielsen identities. This holds for any election of gauge-fixing that leads to an invertible Faddeev-Popov matrix.

  8. Construction of tunnel Bôrik

    Directory of Open Access Journals (Sweden)

    Jozef Čížik

    2009-09-01

    Full Text Available When tunneling engineers talk on NATM, they often mean different things because some of them define it as a special technique,but others as a sort of philosophy. Recently the scene has been complicated by new terms and even alternative names, when discussingcertain aspects of NATM.The NATM integrates the principles of the behaviour of rock masses under load and monitoring the performance of undergroundconstruction during construction. The NATM is not a set of specific excavation and support techniques. Based on the computationof the optimal cross section, just a thin shotcrete protection is necessary. Additionally, geotechnical instruments are installed to measurethe later deformation of excavation. Therefore a monitoring of the stress distribution within the rock is possible. This monitoring makesthe method very flexible, even at surprising changes of the geomechanical rock consistency during the tunneling work.

  9. Convexity, gauge-dependence and tunneling rates

    International Nuclear Information System (INIS)

    Plascencia, Alexis D.; Tamarit, Carlos

    2016-01-01

    We clarify issues of convexity, gauge-dependence and radiative corrections in relation to tunneling rates. Despite the gauge dependence of the effective action at zero and finite temperature, it is shown that tunneling and nucleation rates remain independent of the choice of gauge-fixing. Taking as a starting point the functional that defines the transition amplitude from a false vacuum onto itself, it is shown that decay rates are exactly determined by a non-convex, false vacuum effective action evaluated at an extremum. The latter can be viewed as a generalized bounce configuration, and gauge-independence follows from the appropriate Nielsen identities. This holds for any election of gauge-fixing that leads to an invertible Faddeev-Popov matrix.

  10. Tunnel boring waste test plan

    International Nuclear Information System (INIS)

    Patricio, J.G.

    1984-03-01

    The test plan has been prepared in anticipation of the need to excavate certain repository openings by relying upon mechanical excavation techniques. The test plan proposes that specific technical issues can be resolved and key design parameters defined by excavating openings in basalt near the surface, utilizing a full face tunnel boring machine (TBM). The purpose and objective of this type of testing will define the overall feasibility and attributes of mechanical excavation in basalt. The test plan recognizes that although this technology is generally available for underground construction for some geologic settings, the current state of technology for excavation in basalt is limited and the potential for improvement is considerable. The test plan recommends that it is economically advantageous to conduct additional testing in the laboratory to allow refinement of this plan based on the laboratory results. Thus, this test plan is considered preliminary in nature, with respect to detailed testing recommendations. However, the gross design attributes and resource requirements of a near-surface TBM demonstration are considered to be valid. 15 refs., 7 figs., 3 tabs

  11. What type of rural? Assessing the variations in life expectancy at birth at small area-level for a small population province using classes of locally defined settlement types.

    Science.gov (United States)

    Terashima, Mikiko; Read Guernsey, Judith; Andreou, Pantelis

    2014-02-13

    Although efforts have been made to articulate rural-urban health inequalities in recent years, results have been inconsistent due to different geographical scales used in these studies. Small-area level investigations of health inequalities will likely show more detailed pictures of health inequalities among diverse rural communities, but they are difficult to conduct, particularly in a small population region. The objectives of this study were: 1) to compare life expectancy at birth for females and males across small-areas classified by locally defined settlement types for a small province in Canada; 2) to assess whether any of the settlement types explains variations in life expectancy over and above the extent of socioeconomic disadvantage and social isolation; and 3) to examine variations in life expectancies within a (larger) area unit used as the basis of health inequality investigations in previous studies. Seven settlement types were determined for the 'community' units based on population per-kilometre-road density and settlement forms. Mean life expectancies at birth for both genders were compared by settlement type, both for the entire province and within the Halifax Regional Municipality--the province's only census designated metropolitan area, but also contains rural settlements. Linear regression analyses were conducted to assess the statistical associations between life expectancy and the settlement types, adjusting for indicators of community-level deprivation. While types of communities considered as 'rural' generally had lower life expectancy for both genders, the effects of living in any settlement type were attenuated once adjusted for socioeconomic deprivation and social isolation. An exception was the village and settlement cluster type, which had additionally negative effects on health for females. There were some variations observed within the Halifax Regional Municipality, suggesting the importance of further investigating a variety of

  12. Excavation of the Surikamigawa dam diversion tunnel. Surikamigawa dam karihaisui tunnel kantsu

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, T.; Konno, T. (Ministry of Construction, Tokyo (Japan))

    1994-04-01

    A bypass tunnel construction has been completed at the Surikamigawa dam (Japan). This paper describes the summary of the construction. The full-swing dam construction work is scheduled to begin in 1995. The soils distributed near the dam site consist of lapillus tuff containing andesite-based light stones and tuff-based conglomerates containing large gravels. Excavation of the dam diversion tunnel has used a blasting method, and the tunnel construction has adopted an automatic tunnel cross section marking system and a non-electric explosion method. This marking system is a system to irradiate a laser beam onto the facing to depict excavation lines that realizes labor saving and high-accuracy excavation. The error at the tunnel completion was found 20 mm. The non-electric explosion method ignites a coated explosive layer with an impact wave, which is electrostatically safe, and reduces blasting vibration. Electric detonators have also been used because of using ANFO explosives. The result obtained from measurements of inner space displacement necessary for the blasting process has indicated that the area near the dam site consists of stable mountains. 6 figs., 4 tabs.

  13. D Modelling of Tunnel Excavation Using Pressurized Tunnel Boring Machine in Overconsolidated Soils

    Science.gov (United States)

    Demagh, Rafik; Emeriault, Fabrice

    2013-06-01

    The construction of shallow tunnels in urban areas requires a prior assessment of their effects on the existing structures. In the case of shield tunnel boring machines (TBM), the various construction stages carried out constitute a highly three-dimensional problem of soil/structure interaction and are not easy to represent in a complete numerical simulation. Consequently, the tunnelling- induced soil movements are quite difficult to evaluate. A 3D simulation procedure, using a finite differences code, namely FLAC3D, taking into account, in an explicit manner, the main sources of movements in the soil mass is proposed in this paper. It is illustrated by the particular case of Toulouse Subway Line B for which experimental data are available and where the soil is saturated and highly overconsolidated. A comparison made between the numerical simulation results and the insitu measurements shows that the 3D procedure of simulation proposed is relevant, in particular regarding the adopted representation of the different operations performed by the tunnel boring machine (excavation, confining pressure, shield advancement, installation of the tunnel lining, grouting of the annular void, etc). Furthermore, a parametric study enabled a better understanding of the singular behaviour origin observed on the ground surface and within the solid soil mass, till now not mentioned in the literature.

  14. Aespoe Hard Rock Laboratory. The TASS-tunnel. Geological mapping

    Energy Technology Data Exchange (ETDEWEB)

    Hardenby, Carljohan (Vattenfall Power Consultant AB (Sweden)); Sigurdsson, Oskar (HAskGeokonsult AB (Sweden))

    2010-12-15

    The project entitled 'Sealing of tunnel at great depth' (Fintaetning av tunnel paa stort djup) needed a new tunnel in an area as undisturbed as possible and with cross-cutting water-bearing structures. The new tunnel, which was given the name TASS, was excavated on the -450 m level of SKB's Aespoe Hard Rock Laboratory (Aespoe HRL). The length of the tunnel is approximately 80 m and the theoretical tunnel area 19 m2. As is the case with all the other tunnels of the Aespoe HRL, the new tunnel has been geologically mapped. In addition, laser scanning combined with digital photography has been carried out. The tunnel was also used to test various types of explosives, borehole layouts and drilling techniques. The geological mapping of tunnel floor, walls and roof took place on four major occasions when a halt was made in tunnel excavation to allow for various tests. Before the mapping started on these occasions, laser scanning took place. The tunnel faces were mapped after each round (drilling, blasting and unloading). The present report describes the geological features of the tunnel and briefly how the laser scanning was performed. Water-bearing structures have been compared to similar structures in the neighbouring tunnels. The rock type names used here follow the old established Aespoe HRL nomenclature. Narrow (<0.1 m wide) dykes are normally mapped as fracture fillings. The dominating rock type is Aespoe diorite, which constitutes some 90 % of the rock mass. It is mostly mapped as fresh rock. . Minor constituents of the rock mass are fine-grained granite, hybrid rock, pegmatite, quartz veins/lenses and undifferentiated mafic rock. The mapping of fractures and deformation zones considers a number of parameters such as number of fractures, open/healed, width, length, description of fracture surfaces (roughness, planarity, etc), fracture filling, alteration and water. The deformation zones are discriminated into two main categories (&apos

  15. Aespoe Hard Rock Laboratory. The TASS-tunnel. Geological mapping

    International Nuclear Information System (INIS)

    Hardenby, Carljohan; Sigurdsson, Oskar

    2010-12-01

    The project entitled 'Sealing of tunnel at great depth' (Fintaetning av tunnel paa stort djup) needed a new tunnel in an area as undisturbed as possible and with cross-cutting water-bearing structures. The new tunnel, which was given the name TASS, was excavated on the -450 m level of SKB's Aespoe Hard Rock Laboratory (Aespoe HRL). The length of the tunnel is approximately 80 m and the theoretical tunnel area 19 m 2 . As is the case with all the other tunnels of the Aespoe HRL, the new tunnel has been geologically mapped. In addition, laser scanning combined with digital photography has been carried out. The tunnel was also used to test various types of explosives, borehole layouts and drilling techniques. The geological mapping of tunnel floor, walls and roof took place on four major occasions when a halt was made in tunnel excavation to allow for various tests. Before the mapping started on these occasions, laser scanning took place. The tunnel faces were mapped after each round (drilling, blasting and unloading). The present report describes the geological features of the tunnel and briefly how the laser scanning was performed. Water-bearing structures have been compared to similar structures in the neighbouring tunnels. The rock type names used here follow the old established Aespoe HRL nomenclature. Narrow (<0.1 m wide) dykes are normally mapped as fracture fillings. The dominating rock type is Aespoe diorite, which constitutes some 90 % of the rock mass. It is mostly mapped as fresh rock. . Minor constituents of the rock mass are fine-grained granite, hybrid rock, pegmatite, quartz veins/lenses and undifferentiated mafic rock. The mapping of fractures and deformation zones considers a number of parameters such as number of fractures, open/healed, width, length, description of fracture surfaces (roughness, planarity, etc), fracture filling, alteration and water. The deformation zones are discriminated into two main categories ('increased fracturing' and

  16. Tunnel boring machine applications

    International Nuclear Information System (INIS)

    Bhattacharyya, K.K.; McDonald, R.; Saunders, R.S.

    1992-01-01

    This paper reports that characterization of Yucca Mountain for a potential repository requires construction of an underground Exploratory Studies Facility (ESF). Mechanical excavating methods have been proposed for construction of the ESF as they offer a number of advantages over drilling and blasting at the Yucca Mountain site, including; less ground disturbance and therefore a potential for less adverse effects on the integrity of the site, creation of a more stable excavation cross section requiring less ground support, and an inherently safer and cleaner working environment. The tunnel boring machine (TBM) provides a proven technology for excavating the welded and unwelded Yucca Mountain tuffs. The access ramps and main underground tunnels form the largest part of the ESF underground construction work, and have been designed for excavation by TBM

  17. Programmable ferroelectric tunnel memristor

    Directory of Open Access Journals (Sweden)

    Andy eQuindeau

    2014-02-01

    Full Text Available We report an analogously programmable memristor based on genuine electronic resistive switching combining ferroelectric switching and electron tunneling. The tunnel current through an 8 unit cell thick epitaxial Pb(Zr[0.2]Ti[0.8]O[3] film sandwiched between La[0.7]Sr[0.3]MnO[3] and cobalt electrodes obeys the Kolmogorov-Avrami-Ishibashi model for bidimensional growth with a characteristic switching time in the order of 10^-7 seconds. The analytical description of switching kinetics allows us to develop a characteristic transfer function that has only one parameter viz. the characteristic switching time and fully predicts the resistive states of this type of memristor.

  18. Tunnel support design by comparison of empirical and finite element analysis of the Nahakki tunnel in mohmand agency, pakistan

    Directory of Open Access Journals (Sweden)

    Riaz Asif

    2016-03-01

    Full Text Available The paper analyses the geological conditions of study area, rock mass strength parameters with suitable support structure propositions for the under construction Nahakki tunnel in Mohmand Agency. Geology of study area varies from mica schist to graphitic marble/phyllite to schist. The tunnel ground is classified and divided by the empisical classification systems like Rock mass rating (RMR, Q system (Q, and Geological strength index (GSI. Tunnel support measures are selected based on RMR and Q classification systems. Computer based finite element analysis (FEM has given yet another dimension to design approach. FEM software Phase2 version 7.017 is used to calculate and compare deformations and stress concentrations around the tunnel, analyze interaction of support systems with excavated rock masses and verify and check the validity of empirically determined excavation and support systems.

  19. Effects of tunneling on groundwater flow and swelling of clay-sulfate rocks

    Science.gov (United States)

    Butscher, Christoph; Einstein, Herbert H.; Huggenberger, Peter

    2011-11-01

    Swelling of clay-sulfate rocks is a major threat in tunneling. It is triggered by the transformation of the sulfate mineral anhydrite into gypsum as a result of water inflow in anhydrite-containing layers after tunnel excavation. The present study investigates the hydraulic effects of tunneling on groundwater flow and analyzes how hydraulic changes caused by excavation lead to water inflow into anhydrite-containing layers in the tunnel area. Numerical groundwater models are used to conduct scenario simulations that allow one to relate hydrogeological conditions to rock swelling. The influence of the topographic setting, the excavation-damaged zone around the tunnel, the sealing effect of the tunnel liner, and the geological configuration are analyzed separately. The analysis is performed for synthetic situations and is complemented by a case study from a tunnel in Switzerland. The results illustrate the importance of geological and hydraulic information when assessing the risk of swelling at an actual site.

  20. Hawking Radiation As Tunneling

    International Nuclear Information System (INIS)

    Parikh, Maulik K.; Wilczek, Frank

    2000-01-01

    We present a short and direct derivation of Hawking radiation as a tunneling process, based on particles in a dynamical geometry. The imaginary part of the action for the classically forbidden process is related to the Boltzmann factor for emission at the Hawking temperature. Because the derivation respects conservation laws, the exact spectrum is not precisely thermal. We compare and contrast the problem of spontaneous emission of charged particles from a charged conductor

  1. The beam dump tunnels

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    In these images workers are digging the tunnels that will be used to dump the counter-circulating beams. Travelling just a fraction under the speed of light, the beams at the LHC will each carry the energy of an aircraft carrier travelling at 12 knots. In order to dispose of these beams safely, a beam dump is used to extract the beam and diffuse it before it collides with a radiation shielded graphite target.

  2. Primary Tunnel Junction Thermometry

    International Nuclear Information System (INIS)

    Pekola, Jukka P.; Holmqvist, Tommy; Meschke, Matthias

    2008-01-01

    We describe the concept and experimental demonstration of primary thermometry based on a four-probe measurement of a single tunnel junction embedded within four arrays of junctions. We show that in this configuration random sample specific and environment-related errors can be avoided. This method relates temperature directly to Boltzmann constant, which will form the basis of the definition of temperature and realization of official temperature scales in the future

  3. Hydrodynamic optical soliton tunneling

    Science.gov (United States)

    Sprenger, P.; Hoefer, M. A.; El, G. A.

    2018-03-01

    A notion of hydrodynamic optical soliton tunneling is introduced in which a dark soliton is incident upon an evolving, broad potential barrier that arises from an appropriate variation of the input signal. The barriers considered include smooth rarefaction waves and highly oscillatory dispersive shock waves. Both the soliton and the barrier satisfy the same one-dimensional defocusing nonlinear Schrödinger (NLS) equation, which admits a convenient dispersive hydrodynamic interpretation. Under the scale separation assumption of nonlinear wave (Whitham) modulation theory, the highly nontrivial nonlinear interaction between the soliton and the evolving hydrodynamic barrier is described in terms of self-similar, simple wave solutions to an asymptotic reduction of the Whitham-NLS partial differential equations. One of the Riemann invariants of the reduced modulation system determines the characteristics of a soliton interacting with a mean flow that results in soliton tunneling or trapping. Another Riemann invariant yields the tunneled soliton's phase shift due to hydrodynamic interaction. Soliton interaction with hydrodynamic barriers gives rise to effects that include reversal of the soliton propagation direction and spontaneous soliton cavitation, which further suggest possible methods of dark soliton control in optical fibers.

  4. Resonant Tunneling Spin Pump

    Science.gov (United States)

    Ting, David Z.

    2007-01-01

    The resonant tunneling spin pump is a proposed semiconductor device that would generate spin-polarized electron currents. The resonant tunneling spin pump would be a purely electrical device in the sense that it would not contain any magnetic material and would not rely on an applied magnetic field. Also, unlike prior sources of spin-polarized electron currents, the proposed device would not depend on a source of circularly polarized light. The proposed semiconductor electron-spin filters would exploit the Rashba effect, which can induce energy splitting in what would otherwise be degenerate quantum states, caused by a spin-orbit interaction in conjunction with a structural-inversion asymmetry in the presence of interfacial electric fields in a semiconductor heterostructure. The magnitude of the energy split is proportional to the electron wave number. Theoretical studies have suggested the possibility of devices in which electron energy states would be split by the Rashba effect and spin-polarized currents would be extracted by resonant quantum-mechanical tunneling.

  5. Investigation of time dependent stress at crown of second lining concrete of NATM tunnels for mitigating longitudinal cracks

    OpenAIRE

    Rankoth, Chamila Kumara

    2016-01-01

    In recent past, tunnel constructions in Japan have increased mainly due to the construction of revival road network in Tohoku region in northern part of Honshu Island. Many of the mountainous tunnels constructed in this area utilize New Austrian Tunneling method which has a superior versatility and low initial cost compared to many of other methods. These tunnels are comprised of a double shell lining system. The Inner lining is constructed with shotcrete and the outer lining, which is visibl...

  6. Tunnel flexibility effect on the ground surface acceleration response

    Science.gov (United States)

    Baziar, Mohammad Hassan; Moghadam, Masoud Rabeti; Choo, Yun Wook; Kim, Dong-Soo

    2016-09-01

    Flexibility of underground structures relative to the surrounding medium, referred to as the flexibility ratio, is an important factor that influences their dynamic interaction. This study investigates the flexibility effect of a box-shaped subway tunnel, resting directly on bedrock, on the ground surface acceleration response using a numerical model verified against dynamic centrifuge test results. A comparison of the ground surface acceleration response for tunnel models with different flexibility ratios revealed that the tunnels with different flexibility ratios influence the acceleration response at the ground surface in different ways. Tunnels with lower flexibility ratios have higher acceleration responses at short periods, whereas tunnels with higher flexibility ratios have higher acceleration responses at longer periods. The effect of the flexibility ratio on ground surface acceleration is more prominent in the high range of frequencies. Furthermore, as the flexibility ratio of the tunnel system increases, the acceleration response moves away from the free field response and shifts towards the longer periods. Therefore, the flexibility ratio of the underground tunnels influences the peak ground acceleration (PGA) at the ground surface, and may need to be considered in the seismic zonation of urban areas.

  7. Submucosal tunneling techniques: current perspectives.

    Science.gov (United States)

    Kobara, Hideki; Mori, Hirohito; Rafiq, Kazi; Fujihara, Shintaro; Nishiyama, Noriko; Ayaki, Maki; Yachida, Tatsuo; Matsunaga, Tae; Tani, Johji; Miyoshi, Hisaaki; Yoneyama, Hirohito; Morishita, Asahiro; Oryu, Makoto; Iwama, Hisakazu; Masaki, Tsutomu

    2014-01-01

    Advances in endoscopic submucosal dissection include a submucosal tunneling technique, involving the introduction of tunnels into the submucosa. These tunnels permit safer offset entry into the peritoneal cavity for natural orifice transluminal endoscopic surgery. Technical advantages include the visual identification of the layers of the gut, blood vessels, and subepithelial tumors. The creation of a mucosal flap that minimizes air and fluid leakage into the extraluminal cavity can enhance the safety and efficacy of surgery. This submucosal tunneling technique was adapted for esophageal myotomy, culminating in its application to patients with achalasia. This method, known as per oral endoscopic myotomy, has opened up the new discipline of submucosal endoscopic surgery. Other clinical applications of the submucosal tunneling technique include its use in the removal of gastrointestinal subepithelial tumors and endomicroscopy for the diagnosis of functional and motility disorders. This review suggests that the submucosal tunneling technique, involving a mucosal safety flap, can have potential values for future endoscopic developments.

  8. Semiclassical description of resonant tunneling

    International Nuclear Information System (INIS)

    Bogomolny, E.B.; Rouben, D.C.

    1996-01-01

    A semiclassical formula is calculated for the tunneling current of electrons trapped in a potential well which can tunnel into and across a wide quantum well. The tunneling current is measured at the second interface of this well and the calculations idealized an experimental situation where a strong magnetic field tilted with respect to an electric field was used. It is shown that the contribution to the tunneling current, due to trajectories which begin at the first interface and end on the second, is dominant for periodic orbits which hit both walls of the quantum well. (author)

  9. Terminal area energy management regime investigations utilizing an 0.030-scale model (47-0) of the space shuttle vehicle orbiter configuration 140A/B/C/R in the Ames Research Center 11 x 11 foot transonic wind tunnel (OA148), volume 5

    Science.gov (United States)

    Hawthorne, P. J.

    1976-01-01

    Data obtained in wind tunnel test OA148 are presented. The objectives of the test series were to: (1) obtain pressure distributions, forces and moments over the vehicle 5 orbiter in the thermal area energy management (TAEM) and approach phases of flight; (2) obtain elevon and rudder hinge moments in the TAEM and approach phases of flight; (3) obtain body flap and elevon loads for verification of loads balancing with integrated pressure distributions; and (4) obtain pressure distributions near the short OMS pods in the high subsonic, transonic and low supersonic Mach number regimes.

  10. Current perpendicular to plane giant magnetoresistance and tunneling magnetoresistance treated with unified model

    NARCIS (Netherlands)

    Jonkers, PAE

    2002-01-01

    The conceptual similarity between current perpendicular to plane giant magnetoresistance (CPP-GMR) and tunneling magnetoresistance (TMR) is exploited by utilizing a unified single-particle model accounting for both types of magnetoresistance. By defining structures composed of ferromagnetic,

  11. Sonographic diagnosis of carpal tunnel syndrome: a study in 200 hospital workers

    Directory of Open Access Journals (Sweden)

    Adham do Amaral e Castro

    2015-10-01

    Full Text Available AbstractObjective:To describe the prevalence of carpal tunnel syndrome in a sample of 200 healthy hospital workers, establishing the respective epidemiological associations.Materials and Methods:Two hundred individuals were submitted to wrist ultrasonography to measure the median nerve area. They were questioned and examined for epidemiological data, body mass index, carpal tunnel syndrome signs and symptoms, and submitted to the Boston carpal tunnel questionnaire (BCTQ to evaluate the carpal tunnel syndrome severity. A median nerve area ≥ 9 mm2 was considered to be diagnostic of carpal tunnel syndrome.Results:Carpal tunnel syndrome was diagnosed by ultrasonography in 34% of the sample. It was observed the association of carpal tunnel syndrome with age (p < 0.0001, paresthesia (p < 0.0001, Tinel's test (p < 0.0001, Phalen's test (p< 0.0001, BCTQ score (p < 0.0001, and years of formal education (p < 0.0001. Years of formal education was the only variable identified as an independent risk factor for carpal tunnel syndrome (95% CI = 1.03 to 1.24.Conclusion:The prevalence of carpal tunnel syndrome in a population of hospital workers was of 34%. The number of years of formal education was the only independent risk factor for carpal tunnel syndrome.

  12. Engineers win award for Swiss tunnel

    CERN Multimedia

    2003-01-01

    A Derby engineering consultancy has won the Tunnelling Industry Award 2003 for Excellence in Tunnel Design, offered by the British Tunnelling Society, for its work on the LHC in Geneva, Switzerland (1/2 page).

  13. Tunnel-Site Selection by Remote Sensing Techniques

    Science.gov (United States)

    A study of the role of remote sensing for geologic reconnaissance for tunnel-site selection was commenced. For this study, remote sensing was defined...conventional remote sensing . Future research directions are suggested, and the extension of remote sensing to include airborne passive microwave

  14. Spin-flip tunneling in quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, Lars; Braakman, Floris; Meunier, Tristan; Calado, Victor; Vandersypen, Lieven [Kavli Institute of NanoScience, Delft (Netherlands); Wegscheider, Werner [Institute for Experimental and Applied Physics, University of Regensburg (Germany)

    2010-07-01

    Electron spins in a gate-defined double quantum dot formed in a GaAs/(Al,Ga)As 2DEG are promising candidates for quantum information processing as coherent single spin rotation and spin swap has been demonstrated recently. In this system we investigate the two-electron spin dynamics in the presence of microwaves (5.20 GHz) applied to one side gate. During microwave excitation we observe characteristic photon assisted tunneling (PAT) peaks at the (1,1) to (0,2) charge transition. Some of the PAT peaks are attributed to photon tunneling events between the singlet S(0,2) and the singlet S(1,1) states, a spin-conserving transition. Surprisingly, other PAT peaks stand out by their different external magnetic field dependence. They correspond to tunneling involving a spin-flip, from the (0,2) singlet to a (1,1) triplet. The full spectrum of the observed PAT lines is captured by simulations. This process offers novel possibilities for 2-electron spin manipulation and read-out.

  15. Thermovoltages in vacuum tunneling investigated by scanning tunneling microscopy

    OpenAIRE

    Hoffmann, D. H.; Rettenberger, Armin; Grand, Jean Yves; Läuger, K.; Leiderer, Paul; Dransfeld, Klaus; Möller, Rolf

    1995-01-01

    By heating the tunneling tip of a scanning tunneling microscope the thermoelectric properties of a variable vacuum barrier have been investigated. The lateral variation of the observed thermovoltage will be discussed for polycrystalline gold, stepped surfaces of silver, as well as for copper islands on silver.

  16. Electrical resistivity borehole measurements: application to an urban tunnel site

    Science.gov (United States)

    Denis, A.; Marache, A.; Obellianne, T.; Breysse, D.

    2002-06-01

    This paper shows how it is possible to use wells drilled during geotechnical pre-investigation of a tunneling site to obtain a 2-D image of the resistivity close to a tunnel boring machine. An experimental apparatus is presented which makes it possible to perform single and borehole-to-borehole electrical measurements independent of the geological and hydrogeological context, which can be activated at any moment during the building of the tunnel. This apparatus is first demonstrated through its use on a test site. Numerical simulations and data inversion are used to analyse the experimental results. Finally, electrical resistivity tomography and single-borehole measurements on a tunneling site are presented. Experimental results show the viability of the apparatus and the efficiency of the inverse algorithm, and also highlight the limitations of the electrical resistivity tomography as a tool for geotechnical investigation in urban areas.

  17. InAs/Si Hetero-Junction Nanotube Tunnel Transistors

    KAUST Repository

    Hanna, Amir; Fahad, Hossain M.; Hussain, Muhammad Mustafa

    2015-01-01

    Hetero-structure tunnel junctions in non-planar gate-all-around nanowire (GAA NW) tunnel FETs (TFETs) have shown significant enhancement in ‘ON’ state tunnel current over their all-silicon counterpart. Here we show the unique concept of nanotube TFET in a hetero-structure configuration that is capable of much higher drive current as opposed to that of GAA NW TFETs.Through the use of inner/outer core-shell gates, a single III-V hetero-structured nanotube TFET leverages physically larger tunneling area while achieving higher driver current (ION) and saving real estates by eliminating arraying requirement. Numerical simulations has shown that a 10 nm thin nanotube TFET with a 100 nm core gate has a 5×normalized output current compared to a 10 nm diameter GAA NW TFET.

  18. InAs/Si Hetero-Junction Nanotube Tunnel Transistors

    KAUST Repository

    Hanna, Amir

    2015-04-29

    Hetero-structure tunnel junctions in non-planar gate-all-around nanowire (GAA NW) tunnel FETs (TFETs) have shown significant enhancement in ‘ON’ state tunnel current over their all-silicon counterpart. Here we show the unique concept of nanotube TFET in a hetero-structure configuration that is capable of much higher drive current as opposed to that of GAA NW TFETs.Through the use of inner/outer core-shell gates, a single III-V hetero-structured nanotube TFET leverages physically larger tunneling area while achieving higher driver current (ION) and saving real estates by eliminating arraying requirement. Numerical simulations has shown that a 10 nm thin nanotube TFET with a 100 nm core gate has a 5×normalized output current compared to a 10 nm diameter GAA NW TFET.

  19. Defining Quantum Control Flow

    OpenAIRE

    Ying, Mingsheng; Yu, Nengkun; Feng, Yuan

    2012-01-01

    A remarkable difference between quantum and classical programs is that the control flow of the former can be either classical or quantum. One of the key issues in the theory of quantum programming languages is defining and understanding quantum control flow. A functional language with quantum control flow was defined by Altenkirch and Grattage [\\textit{Proc. LICS'05}, pp. 249-258]. This paper extends their work, and we introduce a general quantum control structure by defining three new quantu...

  20. Can play be defined?

    DEFF Research Database (Denmark)

    Eichberg, Henning

    2015-01-01

    Can play be defined? There is reason to raise critical questions about the established academic demand that at phenomenon – also in humanist studies – should first of all be defined, i.e. de-lineated and by neat lines limited to a “little box” that can be handled. The following chapter develops....... Human beings can very well understand play – or whatever phenomenon in human life – without defining it....

  1. Magnetic tunnel junctions with monolayer hexagonal boron nitride tunnel barriers

    Energy Technology Data Exchange (ETDEWEB)

    Piquemal-Banci, M.; Galceran, R.; Bouzehouane, K.; Anane, A.; Petroff, F.; Fert, A.; Dlubak, B.; Seneor, P. [Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767 (France); Caneva, S.; Martin, M.-B.; Weatherup, R. S.; Kidambi, P. R.; Robertson, J.; Hofmann, S. [Department of Engineering, University of Cambridge, Cambridge CB21PZ (United Kingdom); Xavier, S. [Thales Research and Technology, 1 avenue Augustin Fresnel, Palaiseau 91767 (France)

    2016-03-07

    We report on the integration of atomically thin 2D insulating hexagonal boron nitride (h-BN) tunnel barriers into Co/h-BN/Fe magnetic tunnel junctions (MTJs). The h-BN monolayer is directly grown by chemical vapor deposition on Fe. The Conductive Tip Atomic Force Microscopy (CT-AFM) measurements reveal the homogeneity of the tunnel behavior of our h-BN layers. As expected for tunneling, the resistance depends exponentially on the number of h-BN layers. The h-BN monolayer properties are also characterized through integration into complete MTJ devices. A Tunnel Magnetoresistance of up to 6% is observed for a MTJ based on a single atomically thin h-BN layer.

  2. Optimized electrode configuration for current-in-plane characterization of magnetic tunnel junction stacks

    DEFF Research Database (Denmark)

    Cagliani, Alberto; Kjær, Daniel; Østerberg, Frederik Westergaard

    2017-01-01

    The current-in-plane tunneling technique (CIPT) has been a crucial tool in the development of magnetic tunnel junction stacks suitable for magnetic random access memories (MRAM) for more than a decade. The MRAM development has now reached the maturity to make the transition from the R&D phase...... of electrodes on a multi-electrode probe to reach up to 36% improvement on the repeatability for the resistance area product and the tunneling magnetoresistance measurement, without any hardware modification....

  3. Coherence in Magnetic Quantum Tunneling

    Science.gov (United States)

    Fernandez, Julio F.

    2001-03-01

    Crystals of single molecule magnets such as Mn_12 and Fe8 behave at low temperatures as a collection of independent spins. Magnetic anisotropy barriers slow down spin-flip processes. Their rate Γ becomes temperature independent at sufficiently low temperature. Quantum tunneling (QT) accounts for this behavior. Currently, spin QT in Mn_12 and Fe8 is assumed to proceed as an incoherent sum of small probability increments that occur whenever a bias field h(t) (arising from hyperfine interactions with nuclear spins) that varies with time t becomes sufficiently small, as in Landau-Zener transitions. Within a two-state model, we study the behavior of a suitably defined coherence time τ_φ and compare it with the correlation time τh for h(t). It turns out that τ_φ >τ_h, when τ_hδ h < hbar, where δ h is the rms deviation of h. We show what effect such coherence has on Γ. Its dependence on a static longitudinal applied field Hz is drastically affected. There is however no effect if the field is swept through resonance.

  4. Monitoring and Analysis of Ground Settlement Induced by Tunnelling with Slurry Pressure-Balanced Tunnel Boring Machine

    Directory of Open Access Journals (Sweden)

    Hyunku Park

    2018-01-01

    Full Text Available A case study of monitoring and analysis of ground settlement caused by tunnelling of stacked twin tunnels for underground metro line construction through the densely populated area using the slurry pressure-balanced TBM is presented. Detailed ground settlement monitoring was carried out for the initial stage of down-track tunnelling in order to estimate trough width factor and volume losses including face, shield, and tail losses. In addition, using the gap model, prediction of volume loss and ground settlement was carried out with consideration of the ground condition, TBM configurations, and actual operation data. The predictions of the gap model were compared with the observed results, and adjustment factors were determined for volume loss estimation. The adjusted factors were applied to predict ground settlement of the up-track tunnel, and its results were compared with the field measurements.

  5. Tunneling spectra of graphene on copper unraveled

    DEFF Research Database (Denmark)

    Zhang, Xin; Stradi, Daniele; Liu, Lei

    2016-01-01

    mechanisms, etc. The interpretation of the spectra can be complicated, however. Specifically for graphene grown on copper, there have been conflicting reports of tunneling spectra. A clear understanding of the mechanisms behind the variability is desired. In this work, we have revealed that the root cause...... of the variability in tunneling spectra is the variation in graphene-substrate coupling under various experimental conditions, providing a salutary perspective on the important role of 2D material-substrate interactions. The conclusions are drawn from measured data and theoretical calculations for monolayer, AB......-stacked bilayer, and twisted bilayer graphene coexisting on the same substrates in areas with and without intercalated oxygen, demonstrating a high degree of consistency. The Van Hove singularities of the twisted graphene unambiguously indicate the Dirac energy between them, lending strong evidence to our...

  6. Cryogenic Wind Tunnel Models. Design and Fabrication

    Science.gov (United States)

    Young, C. P., Jr. (Compiler); Gloss, B. B. (Compiler)

    1983-01-01

    The principal motivating factor was the National Transonic Facility (NTF). Since the NTF can achieve significantly higher Reynolds numbers at transonic speeds than other wind tunnels in the world, and will therefore occupy a unique position among ground test facilities, every effort is being made to ensure that model design and fabrication technology exists to allow researchers to take advantage of this high Reynolds number capability. Since a great deal of experience in designing and fabricating cryogenic wind tunnel models does not exist, and since the experience that does exist is scattered over a number of organizations, there is a need to bring existing experience in these areas together and share it among all interested parties. Representatives from government, the airframe industry, and universities are included.

  7. Wind Tunnel Management and Resource Optimization: A Systems Modeling Approach

    Science.gov (United States)

    Jacobs, Derya, A.; Aasen, Curtis A.

    2000-01-01

    Time, money, and, personnel are becoming increasingly scarce resources within government agencies due to a reduction in funding and the desire to demonstrate responsible economic efficiency. The ability of an organization to plan and schedule resources effectively can provide the necessary leverage to improve productivity, provide continuous support to all projects, and insure flexibility in a rapidly changing environment. Without adequate internal controls the organization is forced to rely on external support, waste precious resources, and risk an inefficient response to change. Management systems must be developed and applied that strive to maximize the utility of existing resources in order to achieve the goal of "faster, cheaper, better". An area of concern within NASA Langley Research Center was the scheduling, planning, and resource management of the Wind Tunnel Enterprise operations. Nine wind tunnels make up the Enterprise. Prior to this research, these wind tunnel groups did not employ a rigorous or standardized management planning system. In addition, each wind tunnel unit operated from a position of autonomy, with little coordination of clients, resources, or project control. For operating and planning purposes, each wind tunnel operating unit must balance inputs from a variety of sources. Although each unit is managed by individual Facility Operations groups, other stakeholders influence wind tunnel operations. These groups include, for example, the various researchers and clients who use the facility, the Facility System Engineering Division (FSED) tasked with wind tunnel repair and upgrade, the Langley Research Center (LaRC) Fabrication (FAB) group which fabricates repair parts and provides test model upkeep, the NASA and LARC Strategic Plans, and unscheduled use of the facilities by important clients. Expanding these influences horizontally through nine wind tunnel operations and vertically along the NASA management structure greatly increases the

  8. Effect of tunnel cross section on gas temperatures and heat fluxes in case of large heat release rate

    International Nuclear Information System (INIS)

    Fan, Chuan Gang; Li, Ying Zhen; Ingason, Haukur; Lönnermark, Anders

    2016-01-01

    Highlights: • The effect of tunnel cross section together with ventilation velocity was studied. • Ceiling temperature varies clearly with tunnel height, but little with tunnel width. • Downstream temperature decreases with increasing tunnel dimensions. • HRR is an important factor that influences decay rate of excess gas temperature. • An equation considering both tunnel dimensions and HRR was developed. - Abstract: Tests with liquid and solid fuels in model tunnels (1:20) were performed and analysed in order to study the effect of tunnel cross section (width and height) together with ventilation velocity on ceiling gas temperatures and heat fluxes. The model tunnel was 10 m long with varying width (0.3 m, 0.45 m and 0.6 m) and height (0.25 m and 0.4 m). Test results show that the maximum temperature under the ceiling is a weak function of heat release rate (HRR) and ventilation velocity for cases with HRR more than 100 MW at full scale. It clearly varies with the tunnel height and is a weak function of the tunnel width. With a lower tunnel height, the ceiling is closer to the base of continuous flame zone and the temperatures become higher. Overall, the gas temperature beneath the ceiling decreases with the increasing tunnel dimensions, and increases with the increasing longitudinal ventilation velocity. The HRR is also an important factor that influences the decay rate of excess gas temperature, and a dimensionless HRR integrating HRR and other two key parameters, tunnel cross-sectional area and distance between fuel centre and tunnel ceiling, was introduced to account for the effect. An equation for the decay rate of excess gas temperature, considering both the tunnel dimensions and HRR, was developed. Moreover, a larger tunnel cross-sectional area will lead to a smaller heat flux.

  9. Spin tunnelling in mesoscopic systems

    Indian Academy of Sciences (India)

    We study spin tunnelling in molecular magnets as an instance of a mesoscopic phenomenon, with special emphasis on the molecule Fe8. We show that the tunnel splitting between various pairs of Zeeman levels in this molecule oscillates as a function of applied magnetic field, vanishing completely at special points in the ...

  10. Hawking temperature from tunnelling formalism

    OpenAIRE

    Mitra, P.

    2007-01-01

    It has recently been suggested that the attempt to understand Hawking radiation as tunnelling across black hole horizons produces a Hawking temperature double the standard value. It is explained here how one can obtain the standard value in the same tunnelling approach.

  11. Geological Prediction Ahead of Tunnel Face in the Limestone Formation Tunnel using Multi-Modal Geophysical Surveys

    Science.gov (United States)

    Zaki, N. F. M.; Ismail, M. A. M.; Hazreek Zainal Abidin, Mohd; Madun, Aziman

    2018-04-01

    Tunnel construction in typical karst topography face the risk which unknown geological condition such as abundant rainwater, ground water and cavities. Construction of tunnel in karst limestone frequently lead to potentially over-break of rock formation and cause failure to affected area. Physical character of limestone which consists large cavity prone to sudden failure and become worsen due to misinterpretation of rock quality by engineer and geologists during analysis stage and improper method adopted in construction stage. Consideration for execution of laboratory and field testing in rock limestone should be well planned and arranged in tunnel construction project. Several tests including Ground Penetration Radar (GPR) and geological face mapping were studied in this research to investigate the performances of limestone rock in tunnel construction, measured in term of rock mass quality that used for risk assessment. The objective of this study is to focus on the prediction of geological condition ahead of tunnel face using short range method (GPR) and verified by geological face mapping method to determine the consistency of actual geological condition on site. Q-Value as the main indicator for rock mass classification was obtained from geological face mapping method. The scope of this study is covering for tunnelling construction along 756 meters in karst limestone area which located at Timah Tasoh Tunnel, Bukit Tebing Tinggi, Perlis. For this case study, 15% of GPR results was identified as inaccurate for rock mass classification in which certain chainage along this tunnel with 34 out of 224 data from GPR was identified as incompatible with actual face mapping.

  12. Tunneling Ionization of Diatomic Molecules

    DEFF Research Database (Denmark)

    Svensmark, Jens Søren Sieg

    2016-01-01

    When a molecule is subject to a strong laser field, there is a probability that an electron can escape, even though the electrons are bound by a large potential barrier. This is possible because electrons are quantum mechanical in nature, and they are therefore able to tunnel through potential...... barriers, an ability classical particles do not possess. Tunnelling is a fundamental quantum mechanical process, a process that is distinctly non-classical, so solving this tunnelling problem is not only relevant for molecular physics, but also for quantum theory in general. In this dissertation the theory...... of tunneling ionizaion of molecules is presented and the results of numerical calculations are shown. One perhaps surprising result is, that the frequently used Born-Oppenheimer approximation breaks down for weak fields when describing tunneling ionization. An analytic theory applicable in the weak-field limit...

  13. Tunneling from the past horizon

    Science.gov (United States)

    Kang, Subeom; Yeom, Dong-han

    2018-04-01

    We investigate a tunneling and emission process of a thin-shell from a Schwarzschild black hole, where the shell was initially located beyond the Einstein-Rosen bridge and finally appears at the right side of the Penrose diagram. In order to obtain such a solution, we should assume that the areal radius of the black hole horizon increases after the tunneling. Hence, there is a parameter range such that the tunneling rate is exponentially enhanced, rather than suppressed. We may have two interpretations regarding this. First, such a tunneling process from the past horizon is improbable by physical reasons; second, such a tunneling is possible in principle, but in order to obtain a stable Einstein-Rosen bridge, one needs to restrict the parameter spaces. If such a process is allowed, this can be a nonperturbative contribution to Einstein-Rosen bridges as well as eternal black holes.

  14. ``Phantom'' Modes in Ab Initio Tunneling Calculations: Implications for Theoretical Materials Optimization, Tunneling, and Transport

    Science.gov (United States)

    Barabash, Sergey V.; Pramanik, Dipankar

    2015-03-01

    Development of low-leakage dielectrics for semiconductor industry, together with many other areas of academic and industrial research, increasingly rely upon ab initio tunneling and transport calculations. Complex band structure (CBS) is a powerful formalism to establish the nature of tunneling modes, providing both a deeper understanding and a guided optimization of materials, with practical applications ranging from screening candidate dielectrics for lowest ``ultimate leakage'' to identifying charge-neutrality levels and Fermi level pinning. We demonstrate that CBS is prone to a particular type of spurious ``phantom'' solution, previously deemed true but irrelevant because of a very fast decay. We demonstrate that (i) in complex materials, phantom modes may exhibit very slow decay (appearing as leading tunneling terms implying qualitative and huge quantitative errors), (ii) the phantom modes are spurious, (iii) unlike the pseudopotential ``ghost'' states, phantoms are an apparently unavoidable artifact of large numerical basis sets, (iv) a presumed increase in computational accuracy increases the number of phantoms, effectively corrupting the CBS results despite the higher accuracy achieved in resolving the true CBS modes and the real band structure, and (v) the phantom modes cannot be easily separated from the true CBS modes. We discuss implications for direct transport calculations. The strategy for dealing with the phantom states is discussed in the context of optimizing high-quality high- κ dielectric materials for decreased tunneling leakage.

  15. Fluctuation Dominated Josephson Tunneling with a Scanning Tunneling Microscope

    International Nuclear Information System (INIS)

    Naaman, O.; Teizer, W.; Dynes, R. C.

    2001-01-01

    We demonstrate Josephson tunneling in vacuum tunnel junctions formed between a superconducting scanning tunneling microscope tip and a Pb film, for junction resistances in the range 50--300 k Omega. We show that the superconducting phase dynamics is dominated by thermal fluctuations, and that the Josephson current appears as a peak centered at small finite voltage. In the presence of microwave fields (f=15.0 GHz) the peak decreases in magnitude and shifts to higher voltages with increasing rf power, in agreement with theory

  16. Tunneling junction as an open system. Normal tunneling

    International Nuclear Information System (INIS)

    Ono, Y.

    1978-01-01

    The method of the tunneling Hamiltonian is reformulated in the case of normal tunneling by introducing two independent particle baths. Due to the baths, it becomes possible to realize a final stationary state where the electron numbers of the two electrodes in the tunneling system are maintained constant and where there exists a stationary current. The effect of the bath-system couplings on the current-voltage characteristics of the junction is discussed in relation to the usual expression of the current as a function of voltage. (Auth.)

  17. Frequency driven inversion of tunnel magnetoimpedance and observation of positive tunnel magnetocapacitance in magnetic tunnel junctions

    International Nuclear Information System (INIS)

    Parui, Subir; Ribeiro, Mário; Atxabal, Ainhoa; Llopis, Roger; Bedoya-Pinto, Amilcar; Sun, Xiangnan; Casanova, Fèlix; Hueso, Luis E.

    2016-01-01

    The relevance for modern computation of non-volatile high-frequency memories makes ac-transport measurements of magnetic tunnel junctions (MTJs) crucial for exploring this regime. Here, we demonstrate a frequency-mediated effect in which the tunnel magnetoimpedance reverses its sign in a classical Co/Al 2 O 3 /NiFe MTJ, whereas we only observe a gradual decrease in the tunnel magnetophase. Such effects are explained by the capacitive coupling of a parallel resistor and capacitor in the equivalent circuit model of the MTJ. Furthermore, we report a positive tunnel magnetocapacitance effect, suggesting the presence of a spin-capacitance at the two ferromagnet/tunnel-barrier interfaces. Our results are important for understanding spin transport phenomena at the high frequency regime in which the spin-polarized charge accumulation due to spin-dependent penetration depth at the two interfaces plays a crucial role.

  18. Frequency driven inversion of tunnel magnetoimpedance and observation of positive tunnel magnetocapacitance in magnetic tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Parui, Subir, E-mail: s.parui@nanogune.eu, E-mail: l.hueso@nanogune.eu; Ribeiro, Mário; Atxabal, Ainhoa; Llopis, Roger [CIC nanoGUNE, 20018 Donostia-San Sebastian (Spain); Bedoya-Pinto, Amilcar [CIC nanoGUNE, 20018 Donostia-San Sebastian (Spain); Max Planck Institute of Microstructure Physics, D-06120 Halle (Germany); Sun, Xiangnan [CIC nanoGUNE, 20018 Donostia-San Sebastian (Spain); National Center for Nanoscience and Technology, 100190 Beijing (China); Casanova, Fèlix; Hueso, Luis E., E-mail: s.parui@nanogune.eu, E-mail: l.hueso@nanogune.eu [CIC nanoGUNE, 20018 Donostia-San Sebastian (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain)

    2016-08-01

    The relevance for modern computation of non-volatile high-frequency memories makes ac-transport measurements of magnetic tunnel junctions (MTJs) crucial for exploring this regime. Here, we demonstrate a frequency-mediated effect in which the tunnel magnetoimpedance reverses its sign in a classical Co/Al{sub 2}O{sub 3}/NiFe MTJ, whereas we only observe a gradual decrease in the tunnel magnetophase. Such effects are explained by the capacitive coupling of a parallel resistor and capacitor in the equivalent circuit model of the MTJ. Furthermore, we report a positive tunnel magnetocapacitance effect, suggesting the presence of a spin-capacitance at the two ferromagnet/tunnel-barrier interfaces. Our results are important for understanding spin transport phenomena at the high frequency regime in which the spin-polarized charge accumulation due to spin-dependent penetration depth at the two interfaces plays a crucial role.

  19. Analysis of heat-transfer measurements from 2 AEDC wind tunnels on the Shuttle external tank

    Science.gov (United States)

    Nutt, K. W.

    1984-01-01

    Previous aerodynamic heating tests have been conducted in the AEDC/VKF Supersonic Wind Tunnel (A) to aid in defining the design thermal environment for the space shuttle external tank. The quality of these data has been under discussion because of the effects of low tunnel enthalpy and slow model injection rates. Recently the AEDC/VKF Hypersonic Wind Tunnel (C) has been modified to provide a Mach 4 capability that has significantly higher tunnel enthalpy with more rapid model injection rates. Tests were conducted in Tunnel C at Mach 4 to obtain data on the external tank for comparison with Tunnel A results. Data were obtained on a 0.0175 scale model of the Space Shuttle Integrated Vehicle at Re/ft = 4 x 10 to the 6th power with the tunnel stagnation temperature varying from 740 to 1440 R. Model attitude varied from an angle of attack of -5 to 5 deg and an angle of sideslip of -3 to 3 deg. One set of data was obtained in Tunnel C at Re/ft = 6.9 x 10 to the 6th for comparison with flight data. Data comparisons between the two tunnels for numerous regions on the external tank are given.

  20. Defining Overweight and Obesity

    Science.gov (United States)

    ... Micronutrient Malnutrition State and Local Programs Defining Adult Overweight and Obesity Recommend on Facebook Tweet Share Compartir ... weight for a given height is described as overweight or obese. Body Mass Index, or BMI, is ...

  1. Drinking Levels Defined

    Science.gov (United States)

    ... of Alcohol Consumption Alcohol's Effects on the Body Alcohol Use Disorder Fetal Alcohol Exposure Support & Treatment Alcohol Policy Special ... Definition of Drinking at Low Risk for Developing Alcohol Use Disorder (AUD): For women, low-risk drinking is defined ...

  2. Defining Documentary Film

    DEFF Research Database (Denmark)

    Juel, Henrik

    2006-01-01

    A discussion of various attemts at defining documentary film regarding form, content, truth, stile, genre or reception - and a propoposal of a positive list of essential, but non-exclusive characteristica of documentary film......A discussion of various attemts at defining documentary film regarding form, content, truth, stile, genre or reception - and a propoposal of a positive list of essential, but non-exclusive characteristica of documentary film...

  3. Geometrical and mechanical properties of the fractures and brittle deformation zones based on the ONKALO tunnel mapping, 4390-4990 m tunnel chainage and the technical rooms

    Energy Technology Data Exchange (ETDEWEB)

    Simelius, C. [Poeyry Finland Oy, Vantaa (Finland)

    2014-04-15

    In this report, the rock mechanics parameters of fractures and brittle deformation zones have been estimated in the vicinity of the ONKALO underground research facility at the Olkiluoto site, western Finland. This report is an extension of two previously published reports describing the geometrical and mechanical properties of the fractures and brittle deformation zones based on ONKALO tunnel mapping from tunnel chainages 0-2400 m (Kuula 2010) and 2400-4390 m (Moenkkoenen et al. 2012). This updated report makes use of mapping data from tunnel chainage 4390-4990 m, including the technical rooms located at the -420 m below the sea level. Analysis of the technical rooms is carried out by dividing the premises according to depth into three sections: the demonstration tunnel level, the technical rooms level and the -457 level. The division is executed in order to define the fracture properties in separate areas and to compare the properties with other technical rooms levels. Drillhole data from holes OL-KR1...OL-KR57 is also examined. This report ends the series of three parameterization reports. The defined rock mechanics parameters of the fractures are based on the rock engineering classification quality index, Q', which incorporates the RQD, Jn, Jr and Ja values. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers. No new data from laboratory joint shear and normal tests was available at the time of the report. The fracture wall compressive strength (JCS) data is available from the chainage range 1280-2400 m. New data for fracture wall compressive strength is not available although new Schmidt hammer measurements were performed in order to obtain the ratio of the intact rock mass vs. an intact brittle deformation zone. Estimation of the mechanical properties of the 23 brittle deformation zones (BDZ) is based on the mapped Q' value, which is converted into the GSI value in order to estimate the strength and deformability

  4. Origin of the water drained by the tunnel Graton

    International Nuclear Information System (INIS)

    Plata B, A.

    1992-12-01

    The research of the origin of the water drained by the Graton tunnel was attempted using isotope techniques. During the period of studies (April 1989-October 1992), four field work was executed to sample waters for chemistry, stable isotope and Tritium analysis, an to inject tracers and verify the possible infiltration from the Rimac and Blanco rivers to the tunnel. The results of the stable isotope analysis show that the water drained by the Graton tunnel comes from a basin around 300 meters above the average altitude of the basin where the Graton is located. The Tritium analysis show that the water is relatively modern. Using the model of total mixing, the residence times of the water drained at the km 0.5 and 2.5 are in the order to 45 years. The conductivities of the water of the tunnel is higher than the Rimac river ones because the influence of mine water. The chemical analysis of the water sampled at the downstream end of the tunnel, show that the conservative ions of the water kept almost constant during more than two years. The results of the work with artificial tracer show that there is no significant leakage from the Rimac and Blanco rivers to the Graton tunnel. So far, it can be concluded as a preliminary approach that the Graton tunnel drains relatively modern water originated in another basin. The hydrodynamics of the area of study seems to include a large storage on underground water in the system. The topography, geology and isotopic composition of the water samples, points to the upper Mantaro river basin as the possible source of part of the water drained by the Graton tunnel. (authors). 20 p. 2 figs., 7 ills., 4 tabs

  5. Seasonal variations of 222Rn concentrations in the air of a tunnel located in Nagano City

    International Nuclear Information System (INIS)

    Muramatsu, H.; Tashiro, Y.; Hasegawa, N.; Misawa, C.; Minami, M.

    2000-01-01

    The survey of 222 Rn concentrations in the air of tunnels constructed during World War II at Nagano City has been performed using a solid-state nuclear track detector technique. Concentrations of several thousands Bq m -3 were observed at inner most areas of the tunnel. A seasonal variation was clearly observed; in summer, several times higher concentrations than in winter were observed, which may be due to a stack effect induced by the temperature difference between the tunnel air and the outside air in each season. The concentrations of radon in the tunnel air decrease exponentially towards the openings of the tunnel, which indicates that the radon concentration in the tunnel is basically governed by diffusion and mixing of radon gas with air. (author)

  6. 3D Centrifuge Modeling of the Effect of Twin Tunneling to an Existing Pile Group

    Directory of Open Access Journals (Sweden)

    M. A. Soomr

    2017-10-01

    Full Text Available In densely built urban areas, it is inevitable that tunnels will be constructed near existing pile groups. The bearing capacity of a pile group depends on shear stress along the soil-pile interface and normal stress underneath the pile toe while the two would be adversely affected by the unloading process of tunneling. Although extensive studies have been conducted to investigate the effects of tunnel construction on existing single piles, the influence of twin tunnel advancement on an existing pile group is merely reported in the literature. In this study, a series of three-dimensional centrifuge tests were carried out to investigate the response of an existing pile group under working load subjected to twin tunneling at various locations in dry Toyoura sand. In each twin tunneling test, the first tunnel is constructed near the mid-depth of the pile shaft, while the second tunnel is subsequently constructed either next to, below or right underneath the pile toe (Tests G_ST, G_SB and G_SU, respectively. Among the three tests, the 2nd tunnel excavated near the pile toe (Test G_ST results in the smallest settlement but the largest transverse tilting (0.2% of pile group. Significant bending moment was induced at the pile head (1.4 times of its bending moment capacity due to the 2nd tunnel T. On the contrary, tunneling right underneath the toe of pile (i.e., Test G_SU results in the smallest tilting but largest settlement of the pile group (4.6% of pile diameter and incremental mobilisation of shaft resistance (13%. Due to stress release by the twin tunneling, the axial force taken by the front piles close to tunnels was reduced and partially transferred to the rear piles. This load transfer can increase the axial force in rear piles by 24%.

  7. Time scales of tunneling decay of a localized state

    International Nuclear Information System (INIS)

    Ban, Yue; Muga, J. G.; Sherman, E. Ya.; Buettiker, M.

    2010-01-01

    Motivated by recent time-domain experiments on ultrafast atom ionization, we analyze the transients and time scales that characterize, aside from the relatively long lifetime, the decay of a localized state by tunneling. While the tunneling starts immediately, some time is required for the outgoing flux to develop. This short-term behavior depends strongly on the initial state. For the initial state, tightly localized so that the initial transients are dominated by over-the-barrier motion, the time scale for flux propagation through the barrier is close to the Buettiker-Landauer traversal time. Then a quasistationary, slow-decay process follows, which sets ideal conditions for observing diffraction in time at longer times and distances. To define operationally a tunneling time at the barrier edge, we extrapolate backward the propagation of the wave packet that escaped from the potential. This extrapolated time is considerably longer than the time scale of the flux and density buildup at the barrier edge.

  8. Reducing Wind Tunnel Data Requirements Using Neural Networks

    Science.gov (United States)

    Ross, James C.; Jorgenson, Charles C.; Norgaard, Magnus

    1997-01-01

    The use of neural networks to minimize the amount of data required to completely define the aerodynamic performance of a wind tunnel model is examined. The accuracy requirements for commercial wind tunnel test data are very severe and are difficult to reproduce using neural networks. For the current work, multiple input, single output networks were trained using a Levenberg-Marquardt algorithm for each of the aerodynamic coefficients. When applied to the aerodynamics of a 55% scale model of a U.S. Air Force/ NASA generic fighter configuration, this scheme provided accurate models of the lift, drag, and pitching-moment coefficients. Using only 50% of the data acquired during, the wind tunnel test, the trained neural network had a predictive accuracy equal to or better than the accuracy of the experimental measurements.

  9. 30 CFR 77.211 - Draw-off tunnels; stockpiling and reclaiming operations; general.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Draw-off tunnels; stockpiling and reclaiming operations; general. 77.211 Section 77.211 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.211 Draw-off tunnels; stockpiling and...

  10. Tunneling of Atoms, Nuclei and Molecules

    International Nuclear Information System (INIS)

    Bertulani, C.A.

    2015-01-01

    This is a brief review of few relevant topics on tunneling of composite particles and how the coupling to intrinsic and external degrees of freedom affects tunneling probabilities. I discuss the phenomena of resonant tunneling, different barriers seen by subsystems, damping of resonant tunneling by level bunching and continuum effects due to particle dissociation. (author)

  11. Computational Multiqubit Tunnelling in Programmable Quantum Annealers

    Science.gov (United States)

    2016-08-25

    ARTICLE Received 3 Jun 2015 | Accepted 26 Nov 2015 | Published 7 Jan 2016 Computational multiqubit tunnelling in programmable quantum annealers...state itself. Quantum tunnelling has been hypothesized as an advantageous physical resource for optimization in quantum annealing. However, computational ...qubit tunnelling plays a computational role in a currently available programmable quantum annealer. We devise a probe for tunnelling, a computational

  12. Een systeem voor classificatie van korte tunnels.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1985-01-01

    The most difficult problems in the lighting of tunnels occur in daylight and in particular in the entrance of the tunnel, while drivers approaching the tunnel must be able to look into the tunnel from the outside to detect the road course and eventual obstacles. A classification should The made on

  13. Tunnel fire testing and modeling the Morgex North tunnel experiment

    CERN Document Server

    Borghetti, Fabio; Gandini, Paolo; Frassoldati, Alessio; Tavelli, Silvia

    2017-01-01

    This book aims to cast light on all aspects of tunnel fires, based on experimental activities and theoretical and computational fluid dynamics (CFD) analyses. In particular, the authors describe a transient full-scale fire test (~15 MW), explaining how they designed and performed the experimental activity inside the Morgex North tunnel in Italy. The entire organization of the experiment is described, from preliminary evaluations to the solutions found for management of operational difficulties and safety issues. This fire test allowed the collection of different measurements (temperature, air velocity, smoke composition, pollutant species) useful for validating and improving CFD codes and for testing the real behavior of the tunnel and its safety systems during a diesel oil fire with a significant heat release rate. Finally, the fire dynamics are compared with empirical correlations, CFD simulations, and literature measurements obtained in other similar tunnel fire tests. This book will be of interest to all ...

  14. Apparent tunneling in chemical reactions

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Hansen, Flemming Yssing; Billing, G. D.

    2000-01-01

    A necessary condition for tunneling in a chemical reaction is that the probability of crossing a barrier is non-zero, when the energy of the reactants is below the potential energy of the barrier. Due to the non-classical nature (i.e, momentum uncertainty) of vibrational states this is, however......, not a sufficient condition in order to establish genuine tunneling as a result of quantum dynamics. This proposition is illustrated for a two-dimensional model potential describing dissociative sticking of N-2 on Ru(s). It is suggested that the remarkable heavy atom tunneling, found in this system, is related...

  15. Tunneling progress on the Yucca Mountain Project

    International Nuclear Information System (INIS)

    Hansmire, W.H.; Munzer, R.J.

    1996-01-01

    The current status of tunneling progress on the Yucca Mountain Project (YMP) is presented in this paper. The Exploratory Studies Facility (ESF), a key part of the YMP, has been long in development and construction is ongoing. This is a progress report on the tunneling aspects of the ESF as of January 1, 1996. For purposes of discussion in this summary, the tunneling has progressed in four general phases. The paper describes: tunneling in jointed rock under low stress; tunneling through the Bow Ridge Fault and soft rock; tunneling through the Imbricate Fault Zone; and Tunneling into the candidate repository formation

  16. Does the graft-tunnel friction influence knee joint kinematics and biomechanics after anterior cruciate ligament reconstruction? A finite element study.

    Science.gov (United States)

    Wan, Chao; Hao, Zhixiu

    2018-02-01

    Graft tissues within bone tunnels remain mobile for a long time after anterior cruciate ligament (ACL) reconstruction. However, whether the graft-tunnel friction affects the finite element (FE) simulation of the ACL reconstruction is still unclear. Four friction coefficients (from 0 to 0.3) were simulated in the ACL-reconstructed joint model as well as two loading levels of anterior tibial drawer. The graft-tunnel friction did not affect joint kinematics and the maximal principal strain of the graft. By contrast, both the relative graft-tunnel motion and equivalent strain for the bone tunnels were altered, which corresponded to different processes of graft-tunnel integration and bone remodeling, respectively. It implies that the graft-tunnel friction should be defined properly for studying the graft-tunnel integration or bone remodeling after ACL reconstruction using numerical simulation.

  17. Tunnel magnetoresistance in asymmetric double-barrier magnetic tunnel junctions

    International Nuclear Information System (INIS)

    Useinov, N.Kh.; Petukhov, D.A.; Tagirov, L.R.

    2015-01-01

    The spin-polarized tunnel conductance and tunnel magnetoresistance (TMR) through a planar asymmetric double-barrier magnetic tunnel junction (DBMTJ) have been calculated using quasi-classical model. In DBMTJ nanostructure the magnetization of middle ferromagnetic metal layer can be aligned parallel or antiparallel with respect to the fixed magnetizations of the top and bottom ferromagnetic electrodes. The transmission coefficients of an electron to pass through the barriers have been calculated in terms of quantum mechanics. The dependencies of tunnel conductance and TMR on the applied voltage have been calculated in case of non-resonant transmission. Estimated in the framework of our model, the difference between the spin-channels conductances at low voltages was found relatively large. This gives rise to very high magnitude of TMR. - Highlights: • The spin-polarized conductance through the junction is calculated. • Dependencies of the tunnel conductance vs applied bias are shown. • Bias voltage dependence of tunnel magnetoresistance for the structure is shown

  18. Definably compact groups definable in real closed fields. I

    OpenAIRE

    Barriga, Eliana

    2017-01-01

    We study definably compact definably connected groups definable in a sufficiently saturated real closed field $R$. We introduce the notion of group-generic point for $\\bigvee$-definable groups and show the existence of group-generic points for definably compact groups definable in a sufficiently saturated o-minimal expansion of a real closed field. We use this notion along with some properties of generic sets to prove that for every definably compact definably connected group $G$ definable in...

  19. 28 August 2013 - Ambassador Extraordinary and Plenipotentiary Permanent Representative of Ireland to the United Nations Office and specialized institutions in Geneva Mr G. Corr signing the guest book with CERN Director-General R. Heuer; visiting the LHCb experimental area with LHCb Collaboration Spokesperson P. Campana and visiting the LHC tunnel at Point 8 with International Relations Adviser for Ireland E. Tsesmelis. Accompanied throughout by R. McNulty.

    CERN Multimedia

    Jean-Claude Gadmer

    2013-01-01

    28 August 2013 - Ambassador Extraordinary and Plenipotentiary Permanent Representative of Ireland to the United Nations Office and specialized institutions in Geneva Mr G. Corr signing the guest book with CERN Director-General R. Heuer; visiting the LHCb experimental area with LHCb Collaboration Spokesperson P. Campana and visiting the LHC tunnel at Point 8 with International Relations Adviser for Ireland E. Tsesmelis. Accompanied throughout by R. McNulty.

  20. 9 February 2012 - Permanent Representative of the Kingdom of Spain to the United Nations Office at Geneva and other International Organisations, Ambassador A. Santos Maraver signing the guest book with CERN Director-General; in the CERN Control Centre with N. Catalan; visiting the LHC tunnel at Point 5 and CMS underground experimental area with Collaboration Spokesperson J. Incandela; throughout accompanied by Adviser J. Salicio Diez and Former Physics Deputy Department Head L. Alvarez Gaumé.

    CERN Multimedia

    Visual Media Office

    2012-01-01

    9 February 2012 - Permanent Representative of the Kingdom of Spain to the United Nations Office at Geneva and other International Organisations, Ambassador A. Santos Maraver signing the guest book with CERN Director-General; in the CERN Control Centre with N. Catalan; visiting the LHC tunnel at Point 5 and CMS underground experimental area with Collaboration Spokesperson J. Incandela; throughout accompanied by Adviser J. Salicio Diez and Former Physics Deputy Department Head L. Alvarez Gaumé.

  1. 28 August 2013 - Director of Technical Quality Management Head of ESTEC Establishment European Space Agency F. Ongaro visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry and Technology Department J.-P. Tock; visiting the ATLAS experimental area with ATLAS Deputy Spokesperson T. Wengler and signing the guest book with CERN Director-General R. Heuer. Accompanied throughout by F. Bordry and V. Parma.

    CERN Multimedia

    Jean-Claude Gadmer

    2013-01-01

    28 August 2013 - Director of Technical Quality Management Head of ESTEC Establishment European Space Agency F. Ongaro visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry and Technology Department J.-P. Tock; visiting the ATLAS experimental area with ATLAS Deputy Spokesperson T. Wengler and signing the guest book with CERN Director-General R. Heuer. Accompanied throughout by F. Bordry and V. Parma.

  2. 6 February 2012 - Supreme Audit Institutions from Norway, Poland, Spain and Switzerland visiting the LHC tunnel at Point 5, CMS underground experimental area, CERN Control Centre and LHC superconducting magnet test hall. Delegations are throughout accompanied by Swiss P. Jenni, Polish T. Kurtyka, Spanish J. Salicio, Norwegian S. Stapnes and International Relations Adviser R. Voss. (Riksrevisjonen, Oslo; Tribunal de Cuentas , Madrid; the Court of Audit of Switzerland and Najwyzsza Izba Kontroli, Varsaw)

    CERN Multimedia

    Jean-Claude Gadmer

    2012-01-01

    6 February 2012 - Supreme Audit Institutions from Norway, Poland, Spain and Switzerland visiting the LHC tunnel at Point 5, CMS underground experimental area, CERN Control Centre and LHC superconducting magnet test hall. Delegations are throughout accompanied by Swiss P. Jenni, Polish T. Kurtyka, Spanish J. Salicio, Norwegian S. Stapnes and International Relations Adviser R. Voss. (Riksrevisjonen, Oslo; Tribunal de Cuentas , Madrid; the Court of Audit of Switzerland and Najwyzsza Izba Kontroli, Varsaw)

  3. 6 January 2011 - Extraordinary and plenipotentiary Ambassador M. Kovačič, Permanent Representative of the Republic of Slovenia to the United Nations Office and other international Organisations at Geneva (and Permanent Mission Staff)signing the guest book with CERN Director-General R. Heuer; in the ATLAS visitor centre, ATLAS underground area and LHC tunnel with Collaboration Spokesperson F. Gianotti and Adviser T. Kurtyka.

    CERN Multimedia

    Jean-Claude Gadmer

    2011-01-01

    6 January 2011 - Extraordinary and plenipotentiary Ambassador M. Kovačič, Permanent Representative of the Republic of Slovenia to the United Nations Office and other international Organisations at Geneva (and Permanent Mission Staff)signing the guest book with CERN Director-General R. Heuer; in the ATLAS visitor centre, ATLAS underground area and LHC tunnel with Collaboration Spokesperson F. Gianotti and Adviser T. Kurtyka.

  4. FUNDAMENTAL TUNNELING PROCESSES IN MOSa SOLAR CELLS

    OpenAIRE

    Balberg , I.; Hanak , J.; Weakliem , H.; Gal , E.

    1981-01-01

    In previous studies of tunneling through a MOSa tunnel junction, where Sa was a-Si : H, it was shown that their characteristics resemble those of MOSc devices where Sc was crystalline silicon. In the present work we would like to report a demonstration of fundamental tunneling processes in such tunnel junctions. In particular, the transition from semiconductor controlled regime to tunneling controlled regime can be clearly distinguished. The present results represent one of the rare cases whe...

  5. Destructive quantum interference in spin tunneling problems

    OpenAIRE

    von Delft, Jan; Henley, Christopher L.

    1992-01-01

    In some spin tunneling problems, there are several different but symmetry-related tunneling paths that connect the same initial and final configurations. The topological phase factors of the corresponding tunneling amplitudes can lead to destructive interference between the different paths, so that the total tunneling amplitude is zero. In the study of tunneling between different ground state configurations of the Kagom\\'{e}-lattice quantum Heisenberg antiferromagnet, this occurs when the spi...

  6. 13th Australian tunnelling conference. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    The theme of the conference was 'Engineering in a changing environment'. Topics covered include Australian tunnelling projects, design and development of ground support, tunnelling, international projects, fire and life safety, mining projects, risk management in tunnelling, and tunnel boring machine tunnelling. Papers of particular interest to the coal industry are: improving roadway development in underground coal mine (G. Lewis and G. Gibson), and polymer-based alternative to steel mesh for coal mine strata reinforcement (C. Lukey and others).

  7. Characterization of a New Open Jet Wind Tunnel to Optimize and Test Vertical Axis Wind Turbines Using Flow Visualization and Measurement

    DEFF Research Database (Denmark)

    Tourn, S.; Gilabert, R.; Sánchez, V.

    Characterize a new open jet wind tunnel and define the uniform test section where performance studies of small VAWTs will be carried out.......Characterize a new open jet wind tunnel and define the uniform test section where performance studies of small VAWTs will be carried out....

  8. Tunnelling instability via perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Graffi, S. (Bologna Univ. (Italy). Dip. di Matematica); Grecchi, V. (Moderna Univ. (Italy). Dip. di Matematica); Jona-Lasinio, G. (Paris-11 Univ., 91 - Orsay (France). Lab. de Physique Theorique et Hautes Energies)

    1984-10-21

    The semiclassical limit of low lying states in a multiwell potential is studied by rigorous perturbative techniques. In particular tunnelling instability and localisation of wave functions is obtained in a simple way under small deformations of symmetric potentials.

  9. Scanning Tunneling Microscopy - image interpretation

    International Nuclear Information System (INIS)

    Maca, F.

    1998-01-01

    The basic ideas of image interpretation in Scanning Tunneling Microscopy are presented using simple quantum-mechanical models and supplied with examples of successful application. The importance is stressed of a correct interpretation of this brilliant experimental surface technique

  10. Electron tunneling in proteins program.

    Science.gov (United States)

    Hagras, Muhammad A; Stuchebrukhov, Alexei A

    2016-06-05

    We developed a unique integrated software package (called Electron Tunneling in Proteins Program or ETP) which provides an environment with different capabilities such as tunneling current calculation, semi-empirical quantum mechanical calculation, and molecular modeling simulation for calculation and analysis of electron transfer reactions in proteins. ETP program is developed as a cross-platform client-server program in which all the different calculations are conducted at the server side while only the client terminal displays the resulting calculation outputs in the different supported representations. ETP program is integrated with a set of well-known computational software packages including Gaussian, BALLVIEW, Dowser, pKip, and APBS. In addition, ETP program supports various visualization methods for the tunneling calculation results that assist in a more comprehensive understanding of the tunneling process. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Tunneling Plasmonics in Bilayer Graphene.

    Science.gov (United States)

    Fei, Z; Iwinski, E G; Ni, G X; Zhang, L M; Bao, W; Rodin, A S; Lee, Y; Wagner, M; Liu, M K; Dai, S; Goldflam, M D; Thiemens, M; Keilmann, F; Lau, C N; Castro-Neto, A H; Fogler, M M; Basov, D N

    2015-08-12

    We report experimental signatures of plasmonic effects due to electron tunneling between adjacent graphene layers. At subnanometer separation, such layers can form either a strongly coupled bilayer graphene with a Bernal stacking or a weakly coupled double-layer graphene with a random stacking order. Effects due to interlayer tunneling dominate in the former case but are negligible in the latter. We found through infrared nanoimaging that bilayer graphene supports plasmons with a higher degree of confinement compared to single- and double-layer graphene, a direct consequence of interlayer tunneling. Moreover, we were able to shut off plasmons in bilayer graphene through gating within a wide voltage range. Theoretical modeling indicates that such a plasmon-off region is directly linked to a gapped insulating state of bilayer graphene, yet another implication of interlayer tunneling. Our work uncovers essential plasmonic properties in bilayer graphene and suggests a possibility to achieve novel plasmonic functionalities in graphene few-layers.

  12. Shaft and tunnel sealing considerations

    International Nuclear Information System (INIS)

    Kelsall, P.C.; Shukla, D.K.

    1980-01-01

    Much of the emphasis of previous repository sealing research has been placed on plugging small diameter boreholes. It is increasingly evident that equal emphasis should now be given to shafts and tunnels which constitute more significant pathways between a repository and the biosphere. The paper discusses differences in requirements for sealing shafts and tunnels as compared with boreholes and the implications for seal design. Consideration is given to a design approach for shaft and tunnel seals based on a multiple component design concept, taking into account the requirements for retrievability of the waste. A work plan is developed for the future studies required to advance shaft and tunnel sealing technology to a level comparable with the existing technology for borehole sealing

  13. Organic tunnel field effect transistors

    KAUST Repository

    Tietze, Max Lutz; Lussem, Bjorn; Liu, Shiyi

    2017-01-01

    Various examples are provided for organic tunnel field effect transistors (OTFET), and methods thereof. In one example, an OTFET includes a first intrinsic layer (i-layer) of organic semiconductor material disposed over a gate insulating layer

  14. Bijzondere belastingen in tunnels : Eindrapport

    NARCIS (Netherlands)

    Molenaar, D.J.; Weerheijm, J.; Vervuurt, A.; Burggraaf, H.; Roekaerts, D.; Meijers, P.

    2009-01-01

    Verkeerstunnels en overkapte wegen (landtunnels) komen de milieukundige en stedenbouwkundige inpassing ten goede en maken meervoudig ruimtegebruik in de stad mogelijk. Het aantal tunnels en overkappingen groeit dan ook. Dit maakt het vervoer van explosiegevaarlijke stoffen en onder hoge druk

  15. Free Surface Water Tunnel (FSWT)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: The Free Surface Water Tunnel consists of the intake plenum, the test section and the exit plenum. The intake plenum starts with a perforated pipe that...

  16. Direct, coherent and incoherent intermediate state tunneling and scanning tunnel microscopy (STM)

    International Nuclear Information System (INIS)

    Halbritter, J.

    1997-01-01

    Theory and experiment in tunneling are still qualitative in nature, which hold true also for the latest developments in direct-, resonant-, coherent- and incoherent-tunneling. Those tunnel processes have recently branched out of the field of ''solid state tunnel junctions'' into the fields of scanning tunnel microscopy (STM), single electron tunneling (SET) and semiconducting resonant tunnel structures (RTS). All these fields have promoted the understanding of tunneling in different ways reaching from the effect of coherence, of incoherence and of charging in tunneling, to spin flip or inelastic effects. STM allows not only the accurate measurements of the tunnel current and its voltage dependence but, more importantly, the easy quantification via the (quantum) tunnel channel conductance and the distance dependence. This new degree of freedom entering exponentially the tunnel current allows an unique identification of individual tunnel channels and their quantification. In STM measurements large tunnel currents are observed for large distances d > 1 nm explainable by intermediate state tunneling. Direct tunneling with its reduced tunnel time and reduced off-site Coulomb charging bridges distances below 1 nm, only. The effective charge transfer process with its larger off-site and on-site charging at intermediate states dominates tunnel transfer in STM, biology and chemistry over distances in the nm-range. Intermediates state tunneling becomes variable range hopping conduction for distances larger than d > 2 nm, for larger densities of intermediate states n 1 (ε) and for larger temperatures T or voltages U, still allowing high resolution imaging

  17. Unified semiclassical theory for the two-state system: an analytical solution for general nonadiabatic tunneling.

    Science.gov (United States)

    Zhu, Chaoyuan; Lin, Sheng Hsien

    2006-07-28

    Unified semiclasical solution for general nonadiabatic tunneling between two adiabatic potential energy surfaces is established by employing unified semiclassical solution for pure nonadiabatic transition [C. Zhu, J. Chem. Phys. 105, 4159 (1996)] with the certain symmetry transformation. This symmetry comes from a detailed analysis of the reduced scattering matrix for Landau-Zener type of crossing as a special case of nonadiabatic transition and nonadiabatic tunneling. Traditional classification of crossing and noncrossing types of nonadiabatic transition can be quantitatively defined by the rotation angle of adiabatic-to-diabatic transformation, and this rotational angle enters the analytical solution for general nonadiabatic tunneling. The certain two-state exponential potential models are employed for numerical tests, and the calculations from the present general nonadiabatic tunneling formula are demonstrated in very good agreement with the results from exact quantum mechanical calculations. The present general nonadiabatic tunneling formula can be incorporated with various mixed quantum-classical methods for modeling electronically nonadiabatic processes in photochemistry.

  18. Analysis of an underground structure settlement risk due to tunneling- A case study from Tabriz, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Vahdatirad

    2010-05-01

    Full Text Available The tunnel of the Tabriz urban railway line 2 (TURL2, Iran, will pass through an underground commercial center onits way. Too little distance between the tunnel crown and the underground structure foundation will probably cause collapseor excessive settlement during the tunnel construction based on studied geotechnical conditions of the region. In this paper,a method of risk level assessment for various types of structures, such as frame and masonry structures, and various typesof foundation, such as continuous and isolated, is well defined and the risk level is classified. Moreover, the value of theunderground commercial center structure settlement is estimated using both empirical and numerical methods. The settlementrisk level of the commercial center structure is determined based on presented definitions about risk classification ofvarious types of structures. Consequently, tunneling processes in this section need a special monitoring system and consolidationmeasures before the passage of a tunnel boring machine.

  19. Quantum resonances in physical tunneling

    International Nuclear Information System (INIS)

    Nieto, M.M.; Truax, D.R.

    1985-01-01

    It has recently been emphasized that the probability of quantum tunneling is a critical function of the shape of the potential. Applying this observation to physical systems, we point out that in principal information on potential surfaces can be obtained by studying tunneling rates. This is especially true in cases where only spectral data is known, since many potentials yield the same spectrum. 13 refs., 10 figs., 1 tab

  20. Defining Game Mechanics

    DEFF Research Database (Denmark)

    Sicart (Vila), Miguel Angel

    2008-01-01

    This article defins game mechanics in relation to rules and challenges. Game mechanics are methods invoked by agents for interacting with the game world. I apply this definition to a comparative analysis of the games Rez, Every Extend Extra and Shadow of the Colossus that will show the relevance...... of a formal definition of game mechanics. Udgivelsesdato: Dec 2008...

  1. Modal Logics and Definability

    OpenAIRE

    Kuusisto, Antti

    2013-01-01

    In recent years, research into the mathematical foundations of modal logic has become increasingly popular. One of the main reasons for this is the fact that modal logic seems to adapt well to the requirements of a wide range of different fields of application. This paper is a summary of some of the author’s contributions to the understanding of modal definability theory.

  2. Software Defined Cyberinfrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Foster, Ian; Blaiszik, Ben; Chard, Kyle; Chard, Ryan

    2017-07-17

    Within and across thousands of science labs, researchers and students struggle to manage data produced in experiments, simulations, and analyses. Largely manual research data lifecycle management processes mean that much time is wasted, research results are often irreproducible, and data sharing and reuse remain rare. In response, we propose a new approach to data lifecycle management in which researchers are empowered to define the actions to be performed at individual storage systems when data are created or modified: actions such as analysis, transformation, copying, and publication. We term this approach software-defined cyberinfrastructure because users can implement powerful data management policies by deploying rules to local storage systems, much as software-defined networking allows users to configure networks by deploying rules to switches.We argue that this approach can enable a new class of responsive distributed storage infrastructure that will accelerate research innovation by allowing any researcher to associate data workflows with data sources, whether local or remote, for such purposes as data ingest, characterization, indexing, and sharing. We report on early experiments with this approach in the context of experimental science, in which a simple if-trigger-then-action (IFTA) notation is used to define rules.

  3. Defining Abnormally Low Tenders

    DEFF Research Database (Denmark)

    Ølykke, Grith Skovgaard; Nyström, Johan

    2017-01-01

    The concept of an abnormally low tender is not defined in EU public procurement law. This article takes an interdisciplinary law and economics approach to examine a dataset consisting of Swedish and Danish judgments and verdicts concerning the concept of an abnormally low tender. The purpose...

  4. Software Defined Coded Networking

    DEFF Research Database (Denmark)

    Di Paola, Carla; Roetter, Daniel Enrique Lucani; Palazzo, Sergio

    2017-01-01

    the quality of each link and even across neighbouring links and using simulations to show that an additional reduction of packet transmission in the order of 40% is possible. Second, to advocate for the use of network coding (NC) jointly with software defined networking (SDN) providing an implementation...

  5. Defining depth of anesthesia.

    Science.gov (United States)

    Shafer, S L; Stanski, D R

    2008-01-01

    In this chapter, drawn largely from the synthesis of material that we first presented in the sixth edition of Miller's Anesthesia, Chap 31 (Stanski and Shafer 2005; used by permission of the publisher), we have defined anesthetic depth as the probability of non-response to stimulation, calibrated against the strength of the stimulus, the difficulty of suppressing the response, and the drug-induced probability of non-responsiveness at defined effect site concentrations. This definition requires measurement of multiple different stimuli and responses at well-defined drug concentrations. There is no one stimulus and response measurement that will capture depth of anesthesia in a clinically or scientifically meaningful manner. The "clinical art" of anesthesia requires calibration of these observations of stimuli and responses (verbal responses, movement, tachycardia) against the dose and concentration of anesthetic drugs used to reduce the probability of response, constantly adjusting the administered dose to achieve the desired anesthetic depth. In our definition of "depth of anesthesia" we define the need for two components to create the anesthetic state: hypnosis created with drugs such as propofol or the inhalational anesthetics and analgesia created with the opioids or nitrous oxide. We demonstrate the scientific evidence that profound degrees of hypnosis in the absence of analgesia will not prevent the hemodynamic responses to profoundly noxious stimuli. Also, profound degrees of analgesia do not guarantee unconsciousness. However, the combination of hypnosis and analgesia suppresses hemodynamic response to noxious stimuli and guarantees unconsciousness.

  6. Defining and classifying syncope

    NARCIS (Netherlands)

    Thijs, Roland D.; Wieling, Wouter; Kaufmann, Horacio; van Dijk, Gert

    2004-01-01

    There is no widely adopted definition or classification of syncope and related disorders. This lack of uniformity harms patient care, research, and medical education. In this article, syncope is defined as a form of transient loss of consciousness (TLOC) due to cerebral hypoperfusion. Differences

  7. Three-dimensional scanning force/tunneling spectroscopy at room temperature

    International Nuclear Information System (INIS)

    Sugimoto, Yoshiaki; Ueda, Keiichi; Abe, Masayuki; Morita, Seizo

    2012-01-01

    We simultaneously measured the force and tunneling current in three-dimensional (3D) space on the Si(111)-(7 × 7) surface using scanning force/tunneling microscopy at room temperature. The observables, the frequency shift and the time-averaged tunneling current were converted to the physical quantities of interest, i.e. the interaction force and the instantaneous tunneling current. Using the same tip, the local density of states (LDOS) was mapped on the same surface area at constant height by measuring the time-averaged tunneling current as a function of the bias voltage at every lateral position. LDOS images at negative sample voltages indicate that the tip apex is covered with Si atoms, which is consistent with the Si-Si covalent bonding mechanism for AFM imaging. A measurement technique for 3D force/current mapping and LDOS imaging on the equivalent surface area using the same tip was thus demonstrated. (paper)

  8. Periodontal regenerative management of residual tunnel osseous defect results from the enucleation of lateral periodontal cyst in anterior maxilla: A rare case report

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar Salaria

    2016-01-01

    Full Text Available The lateral periodontal cyst (LPC is a nonkeratinized, noninflammatory developmental cyst occurring adjacent or lateral to tooth root. It is a relatively uncommon lesion found in the maxillary incisors and found mostly in adults during 5th to 7th decades. In this case, 45-year-old male patient reported with occasional mild discomfort between left maxillary central and lateral incisor region since 1 year. Interproximally, a well-defined round radiolucent area with corticated borders was determined radiographically between vital tooth #21 and #22. Preliminary diagnosis of LPC was established based on clinical and radiographical findings. Following enucleation of the lesion, an anticipated residual tunnel osseous defect was observed, which was managed successfully utilizing bone graft and guided tissue regeneration-assisted technique. Cystic tissue removed was examined histologically; hematoxylin- and eosin-stained sections showed features suggestive of LPC. Complete healing of tunnel defect was achieved at 1 year follow-up.

  9. Challenges and Thoughts on Risk Management and Control for the Group Construction of a Super-Long Tunnel by TBM

    Directory of Open Access Journals (Sweden)

    Mingjiang Deng

    2018-02-01

    Full Text Available The total length of the second stage of the water supply project in the northern areas of the Xinjiang Uygur Autonomous Region is 540 km, of which the total length of the tunnels is 516 km. The total tunneling mileage is 569 km, which includes 49 slow-inclined shafts and vertical shafts. Among the tunnels constructed in the project, the Ka–Shuang tunnel, which is a single tunnel with a length of 283 km, is currently the longest water-conveyance tunnel in the world. The main tunnel of the Ka–Shuang tunnel is divided into 18 tunnel-boring machine (TBM sections, and 34 drilling-and-blasting sections, with 91 tunnel faces. The construction of the Ka–Shuang tunnel has been regarded as an unprecedented challenge for project construction management, risk control, and safe and efficient construction; it has also presented higher requirements for the design, manufacture, operation, and maintenance of the TBMs and their supporting equipment. Based on the engineering characteristics and adverse geological conditions, it is necessary to analyze the major problems confronted by the construction and systematically locate disaster sources. In addition, the risk level should be reasonably ranked, responsibility should be clearly identified, and a hierarchical-control mechanism should be established. Several techniques are put forward in this paper to achieve the objectives mentioned above; these include advanced geological prospecting techniques, intelligent tunneling techniques combined with the sensing and fusion of information about rock parameters and mechanical parameters, monitoring and early-warning techniques, and modern information technologies. The application of these techniques offers scientific guidance for risk control and puts forward technical ideas about improving the efficiency of safe tunneling. These techniques and ideas have great significance for the development of modern tunneling technologies and research into major

  10. Tunnelling without barriers

    International Nuclear Information System (INIS)

    Lee, K.

    1987-01-01

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

  11. Design and Development of Low-Cost Water Tunnel for Educational Purpose

    Science.gov (United States)

    Zahari, M.; Dol, S. S.

    2015-04-01

    The hydrodynamic behaviour of immersed body is essential in fluid dynamics study. Water tunnel is an example of facility required to provide a controlled condition for fluid flow research. The operational principle of water tunnel is quite similar to the wind tunnel but with different working fluid and higher flow-pumping capacity. Flow visualization in wind tunnel is more difficult to conduct as turbulent flows in wind dissipate quickly whilst water tunnel is more suitable for such purpose due to higher fluid viscosity and wide variety of visualization techniques can be employed. The present work focusses on the design and development of open flow water tunnel for the purpose of studying vortex-induced vibration from turbulent vortex shedding phenomenon. The water tunnel is designed to provide a steady and uniform flow speed within the test section area. Construction details are discussed for development of low-cost water tunnel for quantitative and qualitative fluid flow measurements. The water tunnel can also be used for educational purpose such as fluid dynamics class activity to provide quick access to visualization medium for better understanding of various turbulence motion learnt in class.

  12. Resonant tunnelling optoelectronic circuits

    NARCIS (Netherlands)

    Figueiredo, J.M.L.; Patarata Romeira, B.M.; Slight, T.J.; Ironside, C.N.; Kim, Ki Young

    2010-01-01

    Nowadays, most communication networks such as local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs) have replaced or are about to replace coaxial cable or twisted copper wire with fiber optical cables. Light-wave communication systems comprise a transmitter

  13. Scanning Tunneling Optical Resonance Microscopy

    Science.gov (United States)

    Bailey, Sheila; Wilt, Dave; Raffaelle, Ryne; Gennett, Tom; Tin, Padetha; Lau, Janice; Castro, Stephanie; Jenkins, Philip; Scheiman, Dave

    2003-01-01

    Scanning tunneling optical resonance microscopy (STORM) is a method, now undergoing development, for measuring optoelectronic properties of materials and devices on the nanoscale by means of a combination of (1) traditional scanning tunneling microscopy (STM) with (2) tunable laser spectroscopy. In STORM, an STM tip probing a semiconductor is illuminated with modulated light at a wavelength in the visible-to-near-infrared range and the resulting photoenhancement of the tunneling current is measured as a function of the illuminating wavelength. The photoenhancement of tunneling current occurs when the laser photon energy is sufficient to excite charge carriers into the conduction band of the semiconductor. Figure 1 schematically depicts a proposed STORM apparatus. The light for illuminating the semiconductor specimen at the STM would be generated by a ring laser that would be tunable across the wavelength range of interest. The laser beam would be chopped by an achromatic liquid-crystal modulator. A polarization-maintaining optical fiber would couple the light to the tip/sample junction of a commercial STM. An STM can be operated in one of two modes: constant height or constant current. A STORM apparatus would be operated in the constant-current mode, in which the height of the tip relative to the specimen would be varied in order to keep the tunneling current constant. In this mode, a feedback control circuit adjusts the voltage applied to a piezoelectric actuator in the STM that adjusts the height of the STM tip to keep the tunneling current constant. The exponential relationship between the tunneling current and tip-to-sample distance makes it relatively easy to implement this mode of operation. The choice of method by which the photoenhanced portion of the tunneling current would be measured depends on choice of the frequency at which the input illumination would be modulated (chopped). If the frequency of modulation were low enough (typically tunneling current

  14. Defining Legal Moralism

    DEFF Research Database (Denmark)

    Thaysen, Jens Damgaard

    2015-01-01

    This paper discusses how legal moralism should be defined. It is argued that legal moralism should be defined as the position that “For any X, it is always a pro tanto reason for justifiably imposing legal regulation on X that X is morally wrong (where “morally wrong” is not conceptually equivalent...... to “harmful”)”. Furthermore, a distinction between six types of legal moralism is made. The six types are grouped according to whether they are concerned with the enforcement of positive or critical morality, and whether they are concerned with criminalising, legally restricting, or refraining from legally...... protecting morally wrong behaviour. This is interesting because not all types of legal moralism are equally vulnerable to the different critiques of legal moralism that have been put forth. Indeed, I show that some interesting types of legal moralism have not been criticised at all....

  15. Electronic noise of superconducting tunnel junction detectors

    International Nuclear Information System (INIS)

    Jochum, J.; Kraus, H.; Gutsche, M.; Kemmather, B.; Feilitzsch, F. v.; Moessbauer, R.L.

    1994-01-01

    The optimal signal to noise ratio for detectors based on superconducting tunnel junctions is calculated and compared for the cases of a detector consisting of one single tunnel junction, as well as of series and of parallel connections of such tunnel junctions. The influence of 1 / f noise and its dependence on the dynamical resistance of tunnel junctions is discussed quantitatively. A single tunnel junction yields the minimum equivalent noise charge. Such a tunnel junction exhibits the best signal to noise ratio if the signal charge is independent of detector size. In case, signal charge increases with detector size, a parallel or a series connection of tunnel junctions would provide the optimum signal to noise ratio. The equivalent noise charge and the respective signal to noise ratio are deduced as functions of tunnel junction parameters such as tunneling time, quasiparticle lifetime, etc. (orig.)

  16. Defining local food

    DEFF Research Database (Denmark)

    Eriksen, Safania Normann

    2013-01-01

    Despite evolving local food research, there is no consistent definition of “local food.” Various understandings are utilized, which have resulted in a diverse landscape of meaning. The main purpose of this paper is to examine how researchers within the local food systems literature define local...... food, and how these definitions can be used as a starting point to identify a new taxonomy of local food based on three domains of proximity....

  17. Rock mechanical conditions at the Aespoe HRL. A study of the correlation between geology, tunnel maintenance and tunnel shape

    International Nuclear Information System (INIS)

    Andersson, Christer; Soederhaell, Joergen

    2001-12-01

    Maintenance records including scaling, shotcreting and bolting have been kept since the excavation start of Aespoe HRL 1990 together with records of groundwater flow and all other activities taking place in the tunnels. When the facility was constructed one objective was to limit the rock support as much as possible. The reason for this was that it should be possible to go back and easily study the exposed rock surface. Support during the operational phase has only been carried out where and when necessary. This type of maintenance and its location is documented in the digital database each time. The maintenance records have been compiled and areas requiring more maintenance than average noted. An interview has also been held with one of the miners conducting scaling and bolting in the tunnel. His experiences together with the study of the database maintenance records led to the selection of certain areas in the tunnel to be studied by numerical modelling. The probable reason for the need of additional maintenance in all areas, not only these numerically modelled, has been investigated. Almost all maintenance in the main tunnel both during construction and the operational phase has been located in the widened curves of the access tunnel. The maintenance is also located in areas containing veins or intrusions of Smaaland granite or fine-grained granite. These areas are often located in fracture zones of different sizes or show an increasing fracture frequency. The areas numerically modelled indicate stress concentrations or unloaded stress conditions. The stress concentrations are created by the geometry of the niches and side-tunnels in relation to the in situ stress field. The angle between the tunnel and the major principal stress has an impact on the need for maintenance. The areas with the largest angles towards the principal stress direction need more maintenance than the areas almost parallel to the major principal stress direction. The maintenance work in

  18. Terminal area energy management regime investigations utilizing an 0.030-scale model (47-0) of the space shuttle vehicle orbiter configuration 140A/B/C/R in the Ames Research Center 11 x 11 foot transonic wind tunnel (0A148), volume 1

    Science.gov (United States)

    Hawthorne, P. J.

    1976-01-01

    Data obtained in wind tunnel tests are presented. The objectives of the tests were to: (1) obtain pressure distributions, forces and moments over the vehicle 5 Orbiter in the terminal area energy management (TAEM) and approach phases of flight; (2) obtain elevon and rudder hinge moments in the TAEM and approach phases of flight; (3) obtain body flap and elevon loads for verification of loads balancing with integrated pressure distributions; and (4) obtain pressure distributions near the short OMS pods in the high subsonic, transonic and low supersonic Mach number regimes. Testing was conducted over a Mach number range from 0.6 to 1.4 with Reynolds number variations from 4.57 million to 2.74 million per foot. Model angle-of-attack was varied from -4 to 16 degrees and angles of side slip ranged from -8 to 8 degrees.

  19. Terminal area energy management regime investigations utilizing an 0.030-scale model (47-0) of the space shuttle vehicle orbiter configuration 140A/B/C/R in the Ames Research Center 11 x 11 foot transonic wind tunnel (OH/48)

    Science.gov (United States)

    Hawthorne, P. J.

    1976-01-01

    Data obtained in a wind tunnel test were examined to: (1) obtain pressure distributions, forces and moments over the vehicle 5 Orbiter in the terminal area energy management (TAEM) and approach phases of flight; (2) obtain elevon and rudder hinge moments in the TAEM and approach phases of flight; (3) obtain body flap and elevon loads for verification of loads balancing with integrated pressure distributions; and (4) obtain pressure distributions near the short OMS pods in the high subsonic, transonic and low supersonic Mach number regimes. Testing was conducted over a Mach number range from 0.6 to 1.4 with Reynolds number variations from 7.57 x 1 million to 2.74 x 1 million per foot. Model angle of attack was varied from -4 to 16 degrees and angles of sideslip ranged from -8 to 8 degrees.

  20. Intercellular Communication in Malignant Pleural Mesothelioma: Properties of Tunneling Nanotubes

    Directory of Open Access Journals (Sweden)

    Justin William Ady

    2014-10-01

    Full Text Available Malignant pleural mesothelioma is a particularly aggressive and locally invasive malignancy with a poor prognosis despite advances in understanding of cancer cell biology and development of new therapies. At the cellular level, cultured mesothelioma cells present a mesenchymal appearance and a strong capacity for local cellular invasion. One important but underexplored area of mesothelioma cell biology is intercellular communication. Our group has previously characterized in multiple histological subtypes of mesothelioma a unique cellular protrusion known as tunneling nanotubes (TnTs. TnTs are long, actin filament-based, narrow cytoplasmic extensions that are non-adherent when cultured in vitro and are capable of shuttling cellular cargo between connected cells. Our prior work confirmed the presence of nanotube structures in tumors resected from patients with human mesothelioma. In our current study, we quantified the number of TnTs/cell among various mesothelioma subtypes and normal mesothelial cells using confocal microscopic techniques. We also examined TnT length among adherent cells and cells in suspension. We further examined potential approaches to the in vivo study of TnTs in animal models of cancer. We have developed novel approaches to study TnTs in aggressive solid tumor malignancies and define fundamental characteristics of TnTs in malignant mesothelioma. There is mounting evidence that TnTs play an important role in intercellular communication in mesothelioma and thus merit further investigation of their role in vivo.

  1. Report Tunneling Cost Reduction Study prepared for Fermilab

    International Nuclear Information System (INIS)

    Not Available

    1999-01-01

    Fermi National Accelerator Laboratories has a need to review the costs of constructing the very long tunnels which would be required for housing the equipment for the proposed Very Large Hadron Collider (VLHC) project. Current tunneling costs are high, and the identification of potential means of significantly reducing them, and thereby helping to keep overall project costs within an acceptable budget, has assumed great importance. Fermilab has contracted with The Robbins Company to provide an up-to-date appraisal of tunneling technology, and to review the potential for substantially improving currently the state-of-practice performance and construction costs in particular. The Robbins Company was chosen for this task because of its long and successful experience in hard rock mechanical tunnel boring. In the past 40 years, Robbins has manufactured over 250 tunneling machines, the vast majority for hard rock applications. In addition to also supplying back-up equipment, Robbins has recently established a division dedicated to the manufacture of continuous conveying equipment for the efficient support of tunneling operations. The study extends beyond the tunnel boring machine (TBM) itself, and into the critical area of the logistics of the support of the machine as it advances, including manpower. It is restricted to proven methods using conventional technology, and its potential for incremental but meaningful improvement, rather than examining exotic and undeveloped means of rock excavation that have been proposed from time to time by the technical community. This is the first phase of what is expected to be a number of studies in increasing depth of technical detail, and as such has been restricted to the issues connected with the initial 34 kilometer circumference booster tunnel, and not the proposed 500 kilometer circumference tunnel housing the VLHC itself. The booster tunnel is entirely sited within low to medium strength limestone and dolomite formations

  2. Operating modes of superconducting tunnel junction device

    Energy Technology Data Exchange (ETDEWEB)

    Maehata, Keisuke [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering

    1998-07-01

    In the Electrotechnical Laboratory, an Nb type superconducting tunnel junction (STJ) device with 200 x 200 sq. micron in area and super high quality was manufactured. By using 55-fe source, response of this large area STJ to X-ray was measured. In this measurement, two action modes with different output wave height from front amplifier were observed. Then, in this study, current-voltage feature of the element in each action mode was analyzed to elucidate a mechanism to form such two action modes. The feature was analyzed by using first order approximate solution on cavity resonance mode of Sine-Gordon equation. From the analytical results, it could be supposed that direction and magnitude of effective magnetic field penetrating into jointed area changed by an induction current effect owing to impressing speed of the magnetic field, which brings two different current-voltage features to make possible to observe two action modes with different pulse wave height. (G.K.)

  3. Theory of superconducting tunneling without the tunneling Hamiltonian

    International Nuclear Information System (INIS)

    Arnold, G.B.

    1987-01-01

    When a tunneling barrier is nearly transparent, the standard tunneling (or transfer) Hamiltonian approximation fails. The author describes the theory which is necessary for calculating the tunneling current in these cases, and illustrate it by comparing theory and experiment on superconductor/insulator/superconductor (SIS) junctions have ultra-thin tunnel barriers. This theory accurately explains the subgap structure which appears in the dynamical resistance of such SIS junctions, including many observed details which no previous theory has reproduced. The expression for the current through an SIS junction with an ultrathin barrier is given by I(t) = Re{Sigma/sub n/ J/sub n/ (omega/sub o/)e/sup in omega/o/sup t/} where omega/sub o/ = 2eV/h is the Josephson frequency, V is the bias voltage, and the J/sub n/ are voltage dependent coefficients, one for each positive or negative integer, n, and n=0. The relative sign of the terms involving cos(n omega/sub o/t) and sin(n omega/sub o/t) agrees with experiment, in contrast to previous theories of Josephson tunneling

  4. Fire analyses in central and disposal tunnels by APROS; Keskus- ja loppusijoitustunneleiden palotarkasteluja APROSilla

    Energy Technology Data Exchange (ETDEWEB)

    Peltokorpi, L.; Kukkola, T.; Nieminen, J. [Fortum Power and Heat Oy, Espoo (Finland)

    2012-12-15

    The central tunnels and the disposal tunnels on the north-east disposal area are the target areas of the fire studies. Target is to maintain under pressure in the fire zone in case of a fire. In the central tunnels a fire of a drilling jumbo with moderate fire propagation is used as heat release rate. In the disposal tunnel the heat release rate of a canister transfer and installation vehicle fire received as a result of the pyrolysis analyze as well as an average heat release rate of a van fire are used. Inlet air is to be conducted to the back end of the fire zone and the exhaust is to be lead out from the beginning of the fire zone. The worst location of the fire is in the beginning of the fire zone just below of the exhaust air clap valve. The size of the fire zone does not have big impact on pressure. In all analyzed cases the fire zone remains too long time over pressurized. Inlet air flow of a 30 m{sup 3}/s is too much. The rotation controlled booster blowers will solve the pressure problems of the fire zone in fire cases. The rotation is controlled by the fire zone pressure. The fire of the canister transfer and installation vehicle in the central tunnel will not cause problems. The disposal tunnel fire door should be kept open, if the canister transfer and installation vehicle or the bentonite blocks transfer and installation vehicle is driven into the disposal tunnel. If a fire is caught in the disposal tunnel then the fire zone in the central tunnel is to be closed and the pressure is controlled by the rotation controlled booster blowers. If a personnel car or a van is driven into the disposal tunnel, then fire door of the disposal is to be kept closed against fires in the central tunnel. (orig.)

  5. Performance of overlapped shield tunneling through an integrated physical model tests, numerical simulations and real-time field monitoring

    Directory of Open Access Journals (Sweden)

    Junlong Yang

    2017-03-01

    Full Text Available In this work, deformations and internal forces of an existing tunnel subjected to a closely overlapped shield tunneling are monitored and analyzed using a series of physical model experiments and numerical simulations. Effects of different excavation sequences and speeds are explicitly considered in the analysis. The results of the physical model experiments show that the bottom-up tunneling procedure is better than the top-down tunneling procedure. The incurred deformations and internal forces of the existing tunnel increase with the excavation speed and the range of influence areas also increase accordingly. For construction process control, real-time monitoring of the power tunnel is used. The monitoring processes feature full automation, adjustable frequency, real-time monitor and dynamic feedback, which are used to guide the construction to achieve micro-disturbance control. In accordance with the situation of crossing construction, a numerical study on the performance of power tunnel is carried out. Construction control measures are given for the undercrossing construction, which helps to accomplish the desired result and meet protection requirements of the existing tunnel structure. Finally, monitoring data and numerical results are compared, and the displacement and joint fracture change models in the power tunnel subject to the overlapped shield tunnel construction are analyzed. Keywords: Overlapped tunnel, Automatic monitoring, Micro-disturbance control

  6. Experimental Investigation of Project Orion Crew Exploration Vehicle Aeroheating in AEDC Tunnel 9

    Science.gov (United States)

    Hollis, Brian R.; Horvath, Thomas J.; Berger, Karen T.; Lillard, Randolph P.; Kirk, Benjamin S.; Coblish, Joseph J.; Norris, Joseph D.

    2008-01-01

    An investigation of the aeroheating environment of the Project Orion Crew Entry Vehicle has been performed in the Arnold Engineering Development Center Tunnel 9. The goals of this test were to measure turbulent heating augmentation levels on the heat shield and to obtain high-fidelity heating data for assessment of computational fluid dynamics methods. Laminar and turbulent predictions were generated for all wind tunnel test conditions and comparisons were performed with the data for the purpose of helping to define uncertainty margins for the computational method. Data from both the wind tunnel test and the computational study are presented herein.

  7. Two-body tunnel transitions in a Mn 4 single-molecule magnet

    Science.gov (United States)

    Wernsdorfer, W.; Bhaduri, S.; Tiron, R.; Hendrickson, D. N.; Christou, G.

    2004-05-01

    The one-body tunnel picture of single-molecule magnets (SMMs) is not always sufficient to explain the measured tunnel transitions. An improvement to the picture is proposed by including also two-body tunnel transitions such as spin-spin cross-relaxation (SSCR) which are mediated by dipolar and weak superexchange interactions between molecules. A Mn 4 SMM is used as a model system. At certain external fields, SSCRs lead to additional quantum resonances which show up in hysteresis loop measurements as well-defined steps.

  8. Tunneling-induced shift of the cutoff law for high-order above-threshold ionization

    International Nuclear Information System (INIS)

    Lai, X. Y.; Quan, W.; Liu, X.

    2011-01-01

    We investigate the cutoff law for high-order above-threshold ionization (HATI) within a semiclassical framework. By explicitly adopting the tunneling effect and considering the initial position shift of the tunneled electron from the origin in the model, the cutoff energy position in HATI spectrum exhibits a well-defined upshift from the simple-man model prediction. The comparison between numerical results from our improved semiclassical model and the quantum-orbit theory shows a good agreement for small values of the Keldysh parameter γ, implying the important role of the inherent quantum tunneling effect in HATI dynamics.

  9. Scaling Projections on Spin-Transfer Torque Magnetic Tunnel Junctions

    Science.gov (United States)

    Das, Debasis; Tulapurkar, Ashwin; Muralidharan, Bhaskaran

    2018-02-01

    We investigate scaling of technologically relevant magnetic tunnel junction devices in the trilayer and pentalayer configurations by varying the cross-sectional area along the transverse direction using the non-equilibrium Green's function spin transport formalism. We study the geometry dependence by considering square and circular cross-sections. As the transverse dimension in each case reduces, we demonstrate that the transverse mode energy profile plays a major role in the resistance-area product. Both types of devices show constant tunnel magnetoresistance at larger cross-sectional areas but achieve ultra-high magnetoresistance at small cross-sectional areas, while maintaining low resistance-area products. We notice that although the critical switching voltage for switching the magnetization of the free layer nanomagnet in the trilayer case remains constant at larger areas, it needs more energy to switch at smaller areas. In the pentalayer case, we observe an oscillatory behavior at smaller areas as a result of double barrier tunneling. We also describe how switching characteristics of both kinds of devices are affected by the scaling.

  10. Large positive spin polarization and giant inverse tunneling magnetoresistance in Fe/PbTiO3/Fe multiferroic tunnel junction

    International Nuclear Information System (INIS)

    Dai, Jian-Qing; Zhang, Hu; Song, Yu-Min

    2014-01-01

    We perform first-principles electronic structure and spin-dependent transport calculations of a multiferroic tunnel junction (MFTJ) with an epitaxial Fe/PbTiO 3 /Fe heterostructure. We predict a large positive spin-polarization (SP) and an intriguing giant inverse tunneling magnetoresistance (TMR) ratio in this tunnel junction. We demonstrate that the tunneling properties are determined by ferroelectric (FE) polarization screening and electronic reconstruction at the interface with lower electrostatic potential. The intricate complex band structure of PbTiO 3 , in particular the lowest decay rates concerning Pb 6p z and Ti 3d z2 states near the Γ ¯ point, gives rise to the large positive SP of the tunneling current in the parallel magnetic configuration. However, the giant inverse TMR ratio is attributed to the minority-spin electrons of the interfacial Ti 3d xz +3d yz orbitals which have considerably weight in the extended area around the Γ ¯ point at the Fermi energy and causes remarkable contributions to the conductance in the antiparallel magnetic configuration. - Highlights: • We study spin-dependent tunneling in Fe/PbTiO 3 /Fe multiferroic tunnel junction. • We find a large positive spin polarization in the parallel magnetic configuration. • An intriguing giant inverse TMR ratio (about −2000%) is predicted. • Complex band structure of PbTiO 3 causes the large positive spin polarization. • Negative TMR is due to minority-spin electrons of interfacial Ti d xz +d yz orbitals

  11. Superconducting tunneling with the tunneling Hamiltonian. II. Subgap harmonic structure

    International Nuclear Information System (INIS)

    Arnold, G.B.

    1987-01-01

    The theory of superconducting tunneling without the tunneling Hamiltonian is extended to treat superconductor/insulator/superconductor junctions in which the transmission coefficient of the insulating barrier approaches unity. The solution for the current in such junctions is obtained by solving the problem of a particle hopping in a one-dimensional lattice of sites, with forward and reverse transfer integrals that depend on the site. The results are applied to the problem of subgap harmonic structure in superconducting tunneling. The time-dependent current at finite voltage through a junction exhibiting subgap structure is found to have terms that oscillate at all integer multiples of the Josephson frequency, n(2eV/h). The amplitudes of these new, and as yet unmeasured, ac current contributions as a function of voltage are predicted

  12. Experimental investigation of tunneling times using Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Ciampini, Donatella; Arimondo, Ennio; Morsch, Oliver

    2011-01-01

    The time it takes a quantum system to complete a tunneling event (which in the case of cross-barrier tunneling can be viewed as the time spent in a classically forbidden area) is related to the time required for a state to evolve to an orthogonal state, and an observation, i.e., a quantum mechanical projection on a particular basis, is required to distinguish one state from another. We have performed time-resolved measurements of Landau-Zener tunneling of Bose-Einstein condensates in accelerated optical lattices, clearly resolving the steplike time dependence of the band populations. The use of different protocols enabled us to access the tunneling probability, in two different bases, namely, the adiabatic basis and the diabatic basis. The adiabatic basis corresponds to the eigenstates of the lattice, and the diabatic one to the free-particle momentum eigenstates. Our findings pave the way towards more quantitative studies of the tunneling time for LZ transitions, which are of current interest in the context of optimal quantum control and the quantum speed limit.

  13. In-vehicle nitrogen dioxide concentrations in road tunnels

    Science.gov (United States)

    Martin, Ashley N.; Boulter, Paul G.; Roddis, Damon; McDonough, Liza; Patterson, Michael; Rodriguez del Barco, Marina; Mattes, Andrew; Knibbs, Luke D.

    2016-11-01

    There is a lack of knowledge regarding in-vehicle concentrations of nitrogen dioxide (NO2) during transit through road tunnels in urban environments. Furthermore, previous studies have tended to involve a single vehicle and the range of in-vehicle NO2 concentrations that vehicle occupants may be exposed to is not well defined. This study describes simultaneous measurements of in-vehicle and outside-vehicle NO2 concentrations on a route through Sydney, Australia that included several major tunnels, minor tunnels and busy surface roads. Tests were conducted on nine passenger vehicles to assess how vehicle characteristics and ventilation settings affected in-vehicle NO2 concentrations and the in-vehicle-to-outside vehicle (I/O) concentration ratio. NO2 was measured directly using a cavity attenuated phase shift (CAPS) technique that gave a high temporal and spatial resolution. In the major tunnels, transit-average in-vehicle NO2 concentrations were lower than outside-vehicle concentrations for all vehicles with cabin air recirculation either on or off. However, markedly lower I/O ratios were obtained with recirculation on (0.08-0.36), suggesting that vehicle occupants can significantly lower their exposure to NO2 in tunnels by switching recirculation on. The highest mean I/O ratios for NO2 were measured in older vehicles (0.35-0.36), which is attributed to older vehicles having higher air exchange rates. The results from this study can be used to inform the design and operation of future road tunnels and modelling of personal exposure to NO2.

  14. Current noise in tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Frey, Moritz; Grabert, Hermann [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Strasse 3, 79104, Freiburg (Germany)

    2017-06-15

    We study current fluctuations in tunnel junctions driven by a voltage source. The voltage is applied to the tunneling element via an impedance providing an electromagnetic environment of the junction. We use circuit theory to relate the fluctuations of the current flowing in the leads of the junction with the voltage fluctuations generated by the environmental impedance and the fluctuations of the tunneling current. The spectrum of current fluctuations is found to consist of three parts: a term arising from the environmental Johnson-Nyquist noise, a term due to the shot noise of the tunneling current and a third term describing the cross-correlation between these two noise sources. Our phenomenological theory reproduces previous results based on the Hamiltonian model for the dynamical Coulomb blockade and provides a simple understanding of the current fluctuation spectrum in terms of circuit theory and properties of the average current. Specific results are given for a tunnel junction driven through a resonator. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Carpal tunnel syndrome - Part I (anatomy, physiology, etiology and diagnosis,

    Directory of Open Access Journals (Sweden)

    Michel Chammas

    2014-10-01

    Full Text Available Carpal tunnel syndrome (CTS is defined by compression of the median nerve in the wrist. It is the commonest of the compressive syndromes and its most frequent cause is idiopathic. Even though spontaneous regression is possible, the general rule is that the symptoms will worsen. The diagnosis is primarily clinical, from the symptoms and provocative tests. Elec-troneuromyographic examination may be recommended before the operation or in cases of occupational illnesses.

  16. Vibrational nonadiabaticity and tunneling effects in transition state theory

    International Nuclear Information System (INIS)

    Marcus, R.A.

    1979-01-01

    The usual quantum mechanical derivation of transition state theory is a statistical one (a quasi-equilibrium is assumed) or dynamical. The typical dynamical one defines a set of internal states and assumes vibrational adiabaticity. Effects of nonadiabaticity before and after the transition state are included in the present derivation, assuming a classical treatment of the reaction coordinate. The relation to a dynamical derivation of classical mechanical transition state theory is described, and tunneling effects are considered

  17. Investigating hydraulic connections and the origin of water in a mine tunnel using stable isotopes and hydrographs

    International Nuclear Information System (INIS)

    Walton-Day, Katherine; Poeter, Eileen

    2009-01-01

    Turquoise Lake is a water-supply reservoir located north of the historic Sugarloaf Mining district near Leadville, Colorado, USA. Elevated water levels in the reservoir may increase flow of low-quality water from abandoned mine tunnels in the Sugarloaf District and degrade water quality downstream. The objective of this study was to understand the sources of water to Dinero mine drainage tunnel and evaluate whether or not there was a direct hydrologic connection between Dinero mine tunnel and Turquoise Lake from late 2002 to early 2008. This study utilized hydrograph data from nearby draining mine tunnels and the lake, and stable isotope (δ 18 O and δ 2 H) data from the lake, nearby draining mine tunnels, imported water, and springs to characterize water sources in the study area. Hydrograph results indicate that flow from the Dinero mine tunnel decreased 26% (2006) and 10% (2007) when lake elevation (above mean sea level) decreased below approximately 3004 m (approximately 9855 feet). Results of isotope analysis delineated two meteoric water lines in the study area. One line characterizes surface water and water imported to the study area from the western side of the Continental Divide. The other line characterizes groundwater including draining mine tunnels, springs, and seeps. Isotope mixing calculations indicate that water from Turquoise Lake or seasonal groundwater recharge from snowmelt represents approximately 10% or less of the water in Dinero mine tunnel. However, most of the water in Dinero mine tunnel is from deep groundwater having minimal isotopic variation. The asymmetric shape of the Dinero mine tunnel hydrograph may indicate that a limited mine pool exists behind a collapse in the tunnel and attenutates seasonal recharge. Alternatively, a conceptual model is presented (and supported with MODFLOW simulations) that is consistent with current and previous data collected in the study area, and illustrates how fluctuating lake levels change the local

  18. Investigating hydraulic connections and the origin of water in a mine tunnel using stable isotopes and hydrographs

    Science.gov (United States)

    Walton-Day, Katherine; Poeter, Eileen

    2009-01-01

    Turquoise Lake is a water-supply reservoir located north of the historic Sugarloaf Mining district near Leadville, Colorado, USA. Elevated water levels in the reservoir may increase flow of low-quality water from abandoned mine tunnels in the Sugarloaf District and degrade water quality downstream. The objective of this study was to understand the sources of water to Dinero mine drainage tunnel and evaluate whether or not there was a direct hydrologic connection between Dinero mine tunnel and Turquoise Lake from late 2002 to early 2008. This study utilized hydrograph data from nearby draining mine tunnels and the lake, and stable isotope (δ18O and δ2H) data from the lake, nearby draining mine tunnels, imported water, and springs to characterize water sources in the study area. Hydrograph results indicate that flow from the Dinero mine tunnel decreased 26% (2006) and 10% (2007) when lake elevation (above mean sea level) decreased below approximately 3004 m (approximately 9855 feet). Results of isotope analysis delineated two meteoric water lines in the study area. One line characterizes surface water and water imported to the study area from the western side of the Continental Divide. The other line characterizes groundwater including draining mine tunnels, springs, and seeps. Isotope mixing calculations indicate that water from Turquoise Lake or seasonal groundwater recharge from snowmelt represents approximately 10% or less of the water in Dinero mine tunnel. However, most of the water in Dinero mine tunnel is from deep groundwater having minimal isotopic variation. The asymmetric shape of the Dinero mine tunnel hydrograph may indicate that a limited mine pool exists behind a collapse in the tunnel and attenutates seasonal recharge. Alternatively, a conceptual model is presented (and supported with MODFLOW simulations) that is consistent with current and previous data collected in the study area, and illustrates how fluctuating lake levels change the local water

  19. Defining persistent hotspots

    DEFF Research Database (Denmark)

    Kittur, Nupur; Binder, Sue; Campbell, Carl H.

    2017-01-01

    Preventive chemotherapy with praziquantel for schistosomiasis morbidity control is commonly done by mass drug administration (MDA). MDA regimen is usually based on prevalence in a given area, and effectiveness is evaluated by decreases in prevalence and/or intensity of infection after several yea...

  20. Hybrid inflation exit through tunneling

    International Nuclear Information System (INIS)

    Garbrecht, Bjoern; Konstandin, Thomas

    2007-01-01

    For hybrid inflationary potentials, we derive the tunneling rate from field configurations along the flat direction towards the waterfall regime. This process competes with the classically rolling evolution of the scalar fields and needs to be strongly subdominant for phenomenologically viable models. Tunneling may exclude models with a mass scale below 10 12 GeV, but can be suppressed by small values of the coupling constants. We find that tunneling is negligible for those models, which do not require fine tuning in order to cancel radiative corrections, in particular for GUT-scale SUSY inflation. In contrast, electroweak scale hybrid inflation is not viable, unless the inflaton-waterfall field coupling is smaller than approximately 10 -11

  1. Defined contribution health benefits.

    Science.gov (United States)

    Fronstin, P

    2001-03-01

    This Issue Brief discusses the emerging issue of "defined contribution" (DC) health benefits. The term "defined contribution" is used to describe a wide variety of approaches to the provision of health benefits, all of which have in common a shift in the responsibility for payment and selection of health care services from employers to employees. DC health benefits often are mentioned in the context of enabling employers to control their outlay for health benefits by avoiding increases in health care costs. DC health benefits may also shift responsibility for choosing a health plan and the associated risks of choosing a plan from employers to employees. There are three primary reasons why some employers currently are considering some sort of DC approach. First, they are once again looking for ways to keep their health care cost increases in line with overall inflation. Second, some employers are concerned that the public "backlash" against managed care will result in new legislation, regulations, and litigation that will further increase their health care costs if they do not distance themselves from health care decisions. Third, employers have modified not only most employee benefit plans, but labor market practices in general, by giving workers more choice, control, and flexibility. DC-type health benefits have existed as cafeteria plans since the 1980s. A cafeteria plan gives each employee the opportunity to determine the allocation of his or her total compensation (within employer-defined limits) among various employee benefits (primarily retirement or health). Most types of DC health benefits currently being discussed could be provided within the existing employment-based health insurance system, with or without the use of cafeteria plans. They could also allow employees to purchase health insurance directly from insurers, or they could drive new technologies and new forms of risk pooling through which health care services are provided and financed. DC health

  2. Quantum mechanical tunneling in chemical physics

    CERN Document Server

    Nakamura, Hiroki

    2016-01-01

    Quantum mechanical tunneling plays important roles in a wide range of natural sciences, from nuclear and solid-state physics to proton transfer and chemical reactions in chemistry and biology. Responding to the need for further understanding of multidimensional tunneling, the authors have recently developed practical methods that can be applied to multidimensional systems. Quantum Mechanical Tunneling in Chemical Physics presents basic theories, as well as original ones developed by the authors. It also provides methodologies and numerical applications to real molecular systems. The book offers information so readers can understand the basic concepts and dynamics of multidimensional tunneling phenomena and use the described methods for various molecular spectroscopy and chemical dynamics problems. The text focuses on three tunneling phenomena: (1) energy splitting, or tunneling splitting, in symmetric double well potential, (2) decay of metastable state through tunneling, and (3) tunneling effects in chemical...

  3. Tunnel Boring Machine Performance Study. Final Report

    Science.gov (United States)

    1984-06-01

    Full face tunnel boring machine "TBM" performance during the excavation of 6 tunnels in sedimentary rock is considered in terms of utilization, penetration rates and cutter wear. The construction records are analyzed and the results are used to inves...

  4. Implementing Software Defined Radio

    CERN Document Server

    Grayver, Eugene

    2013-01-01

    Software Defined Radio makes wireless communications easier, more efficient, and more reliable. This book bridges the gap between academic research and practical implementation. When beginning a project, practicing engineers, technical managers, and graduate students can save countless hours by considering the concepts presented in these pages. The author covers the myriad options and trade-offs available when selecting an appropriate hardware architecture. As demonstrated here, the choice between hardware- and software-centric architecture can mean the difference between meeting an aggressive schedule and bogging down in endless design iterations. Because of the author’s experience overseeing dozens of failed and successful developments, he is able to present many real-life examples. Some of the key concepts covered are: Choosing the right architecture for the market – laboratory, military, or commercial Hardware platforms – FPGAs, GPPs, specialized and hybrid devices Standardization efforts to ens...

  5. Defining the mobilome.

    Science.gov (United States)

    Siefert, Janet L

    2009-01-01

    This chapter defines the agents that provide for the movement of genetic material which fuels the adaptive potential of life on our planet. The chapter has been structured to be broadly comprehensive, arbitrarily categorizing the mobilome into four classes: (1) transposons, (2) plasmids, (3) bacteriophage, and (4) self-splicing molecular parasites.Our increasing understanding of the mobilome is as dynamic as the mobilome itself. With continuing discovery, it is clear that nature has not confined these genomic agents of change to neat categories, but rather the classification categories overlap and intertwine. Massive sequencing efforts and their published analyses are continuing to refine our understanding of the extent of the mobilome. This chapter provides a framework to describe our current understanding of the mobilome and a foundation on which appreciation of its impact on genome evolution can be understood.

  6. Software Defined Networking

    DEFF Research Database (Denmark)

    Caba, Cosmin Marius

    Network Service Providers (NSP) often choose to overprovision their networks instead of deploying proper Quality of Services (QoS) mechanisms that allow for traffic differentiation and predictable quality. This tendency of overprovisioning is not sustainable for the simple reason that network...... resources are limited. Hence, to counteract this trend, current QoS mechanisms must become simpler to deploy and operate, in order to motivate NSPs to employ QoS techniques instead of overprovisioning. Software Defined Networking (SDN) represents a paradigm shift in the way telecommunication and data...... generic perspective (e.g. service provisioning speed, resources availability). As a result, new mechanisms for providing QoS are proposed, solutions for SDN-specific QoS challenges are designed and tested, and new network management concepts are prototyped, all aiming to improve QoS for network services...

  7. Attoclock reveals natural coordinates of the laser-induced tunnelling current flow in atoms

    DEFF Research Database (Denmark)

    Pfeiffer, Adrian N.; Cirelli, Claudio; Smolarski, Mathias

    2012-01-01

    the attoclock technique4 to obtain experimental information about the electron tunnelling geometry (the natural coordinates of the tunnelling current flow) and exit point. We confirm vanishing tunnelling delay time, show the importance of the inclusion of Stark shifts5, 6 and report on multi-electron effects......In the research area of strong-laser-field interactions and attosecond science1, tunnelling of an electron through the barrier formed by the electric field of the laser and the atomic potential is typically assumed to be the initial key process that triggers subsequent dynamics1, 2, 3. Here we use...... clearly identified by comparing results in argon and helium atoms. Our combined theory and experiment allows us to single out the geometry of the inherently one-dimensional tunnelling problem, through an asymptotic separation of the full three-dimensional problem. Our findings have implications for laser...

  8. Transit time for resonant tunneling

    International Nuclear Information System (INIS)

    Garcia Calderon, G.; Rubio, A.

    1990-09-01

    This work considers properties of the partial widths in one dimensional elastic resonant tunneling in order to propose a transit-time τ tr = (h/2π)/Γ n T res ) where Γ n is the elastic width and T res the transmission coefficient at resonance energy. This time is interpreted as an average over the resonance energy width. It is shown that the tunneling current density integrated across a sharp resonance is inversely proportional to τ tr . This transit time may be much larger than the values predicted by other definitions. (author). 20 refs

  9. Spin tunnelling in mesoscopic systems

    Science.gov (United States)

    Garg, Anupam

    2001-02-01

    We study spin tunnelling in molecular magnets as an instance of a mesoscopic phenomenon, with special emphasis on the molecule Fe8. We show that the tunnel splitting between various pairs of Zeeman levels in this molecule oscillates as a function of applied magnetic field, vanishing completely at special points in the space of magnetic fields, known as diabolical points. This phenomena is explained in terms of two approaches, one based on spin-coherent-state path integrals, and the other on a generalization of the phase integral (or WKB) method to difference equations. Explicit formulas for the diabolical points are obtained for a model Hamiltonian.

  10. Tunneling field effect transistor technology

    CERN Document Server

    Chan, Mansun

    2016-01-01

    This book provides a single-source reference to the state-of-the art in tunneling field effect transistors (TFETs). Readers will learn the TFETs physics from advanced atomistic simulations, the TFETs fabrication process and the important roles that TFETs will play in enabling integrated circuit designs for power efficiency. · Provides comprehensive reference to tunneling field effect transistors (TFETs); · Covers all aspects of TFETs, from device process to modeling and applications; · Enables design of power-efficient integrated circuits, with low power consumption TFETs.

  11. Inelastic scattering in resonant tunneling

    DEFF Research Database (Denmark)

    Wingreen, Ned S.; Jacobsen, Karsten Wedel; Wilkins, John W.

    1989-01-01

    The exact resonant-tunneling transmission probability for an electron interacting with phonons is presented in the limit that the elastic coupling to the leads is independent of energy. The phonons produce transmission sidebands but do not affect the integrated transmission probability or the esc......The exact resonant-tunneling transmission probability for an electron interacting with phonons is presented in the limit that the elastic coupling to the leads is independent of energy. The phonons produce transmission sidebands but do not affect the integrated transmission probability...

  12. Molecular series-tunneling junctions.

    Science.gov (United States)

    Liao, Kung-Ching; Hsu, Liang-Yan; Bowers, Carleen M; Rabitz, Herschel; Whitesides, George M

    2015-05-13

    Charge transport through junctions consisting of insulating molecular units is a quantum phenomenon that cannot be described adequately by classical circuit laws. This paper explores tunneling current densities in self-assembled monolayer (SAM)-based junctions with the structure Ag(TS)/O2C-R1-R2-H//Ga2O3/EGaIn, where Ag(TS) is template-stripped silver and EGaIn is the eutectic alloy of gallium and indium; R1 and R2 refer to two classes of insulating molecular units-(CH2)n and (C6H4)m-that are connected in series and have different tunneling decay constants in the Simmons equation. These junctions can be analyzed as a form of series-tunneling junctions based on the observation that permuting the order of R1 and R2 in the junction does not alter the overall rate of charge transport. By using the Ag/O2C interface, this system decouples the highest occupied molecular orbital (HOMO, which is localized on the carboxylate group) from strong interactions with the R1 and R2 units. The differences in rates of tunneling are thus determined by the electronic structure of the groups R1 and R2; these differences are not influenced by the order of R1 and R2 in the SAM. In an electrical potential model that rationalizes this observation, R1 and R2 contribute independently to the height of the barrier. This model explicitly assumes that contributions to rates of tunneling from the Ag(TS)/O2C and H//Ga2O3 interfaces are constant across the series examined. The current density of these series-tunneling junctions can be described by J(V) = J0(V) exp(-β1d1 - β2d2), where J(V) is the current density (A/cm(2)) at applied voltage V and βi and di are the parameters describing the attenuation of the tunneling current through a rectangular tunneling barrier, with width d and a height related to the attenuation factor β.

  13. Watertightness of concrete tunnel structures

    OpenAIRE

    Glerum, A.

    1982-01-01

    The Netherlands are situated in the delta. of the rivers Rhine, Meuse and Scheldt. Therefore the ground mainly consists.of sediments, such as sand, clay and silt. In certain regions peat layers of varying thickness are found. The high permeability of some of these materials and the fact that the groundwater table is generally only 1 m below ground level, make an adequate watertightness one of the main features of tunnel engineering in the Netherlands. Tunnels in Holland are both of the immers...

  14. Enhanced tunneling through nonstationary barriers

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  15. Drill and blast tunnelling; Konvensjonell drift av tunneler

    Energy Technology Data Exchange (ETDEWEB)

    Roenn, Paal-Egil

    1997-12-31

    This thesis treats drill and blast tunnelling. The rapid technological advance necessitates revised and updated design criteria, quality requirements and quality control. In situ blast experiments were carried out in order to test new methods and improve the basis for calculation and design. The main topics of the experiments were (1) longer rounds and increased drillhole diameter, (2) emulsion slurry as explosives in tunnelling, and (3) electronic detonators in contour blasting. The experiments show that it is technically feasible to blast rounds of up to 8.6 m length. Using current technology, the economical optimum round length is substantially shorter. Dust, low visibility, noise and toxic fumes are occupational environmental strains for the tunnel workers. Several of the environmental factors are strongly influenced by the type of explosives used. For example, emulsion slurry resulted in 4 to 5 times better visibility than Anolit and the concentration of respirable dust and total dust was reduced by 30-50 %. Electronic detonators were tested and found to give a higher percentage of remaining drillholes in the contour than Nonel detonators. The thesis includes a chapter on economic design of hydropower tunnels. 42 refs., 83 figs., 45 tabs.

  16. Spin-dependent tunnelling in magnetic tunnel junctions

    International Nuclear Information System (INIS)

    Tsymbal, Evgeny Y; Mryasov, Oleg N; LeClair, Patrick R

    2003-01-01

    The phenomenon of electron tunnelling has been known since the advent of quantum mechanics, but continues to enrich our understanding of many fields of physics, as well as creating sub-fields on its own. Spin-dependent tunnelling (SDT) in magnetic tunnel junctions (MTJs) has recently aroused enormous interest and has developed in a vigorous field of research. The large tunnelling magnetoresistance (TMR) observed in MTJs garnered much attention due to possible applications in non-volatile random-access memories and next-generation magnetic field sensors. This led to a number of fundamental questions regarding the phenomenon of SDT. In this review article we present an overview of this field of research. We discuss various factors that control the spin polarization and magnetoresistance in MTJs. Starting from early experiments on SDT and their interpretation, we consider thereafter recent experiments and models which highlight the role of the electronic structure of the ferromagnets, the insulating layer, and the ferromagnet/insulator interfaces. We also discuss the role of disorder in the barrier and in the ferromagnetic electrodes and their influence on TMR. (topical review)

  17. Inferior tendon graft to bone tunnel healing at the tibia compared to that at the femur after anterior cruciate ligament reconstruction

    International Nuclear Information System (INIS)

    Lui, P.P.Y.; Ho, G.; Shum, W.T.; Lee, Y.W.; Ho, P.Y.; Lo, W.N.; Lo, C.K.

    2010-01-01

    Tunnel widening after anterior cruciate ligament (ACL) reconstruction (ACLR) is commonly reported without a clear understanding of the mechanism. This study aimed to quantify the spatiotemporal change of the newly formed bone mass, bone tunnel diameter, and area along both bone tunnels using micro-computed tomography (μCT) and correlated the result with histology. ACLR was performed in 24 rabbits. At baseline and weeks 2, 6, and 12, the juxta-articular, middle, and exit segments of both tunnels were harvested for μCT and histological evaluation. μCT and histology revealed significant bone tunnel and graft-bone tunnel healing, respectively, only at week 6 after reconstruction. Despite this, the mean tunnel diameter and area remained relatively unchanged with time. The newly formed bone mass [new bone volume/total bone volume (BV/TV) ratio] and its bone mineral density (BMD) were both higher, whereas the mean tunnel diameter and area were significantly smaller at the femoral tunnel compared to those at the tibial tunnel at weeks 6 and 12 and at week 12, respectively. These were consistent with histological findings, which showed inferior graft remodeling and integration at the tibial tunnel at weeks 6 and 12. The BV/TV increased, whereas the mean tunnel diameter and area decreased toward the exit segment of both tunnels. However, whereas better histological healing occurred at the femoral exit segment, poorer graft remodeling and Sharpey's fiber formation occurred at the tibial exit segment. Poor healing was observed during the initial 6 weeks, particularly that of the tibia, after ACLR. Bone resorption was rapid during healing, resulting in unchanged tunnel diameter and area with time. (author)

  18. Aespoe HRL. Experiences of blasting of the TASQ tunnel

    International Nuclear Information System (INIS)

    Olsson, Mats; Niklasson, Bengt; Wilson, Lasse; Andersson, Christer; Christiansson, Rolf

    2004-11-01

    A new tunnel was developed at the Aespoe Hard Rock Laboratory (AHRL) during the spring and summer 2003. The tunnel was specially designed for a rock mechanics experiment, the Aespoe Pillar Stability Experiment (APSE). In this pillar experiment there was a high demand to initiate high in-situ stresses and therefore the tunnel was designed with a large height/ width ratio and with a circular floor. There were high requirements on bore hole precision and of a minimized EDZ (Excavation damaged zone) in the pillar area. This included a maximum borehole deviation of 10 mm/m, a maximum overbreak due to the lookout angle of 0.3 m and an EDZ of 0.3 m. To make a charge control feasible cartridged explosives was prescribed. The initiation was made with Nonel. The last three rounds used electronic initiation to enable studies of possibility to further reduce the EDZ. The collar of the tunnel was very close to installations and shaft and it was very important to avoid fly-rock and vibrations. Special types of stemming were used as well as steel plates and rubber mats. The excavation works was divided in three different phases. The first phase of the tunnel was an ordinary 26 m 2 tunnel. After approximately 30 m a ramp separated the tunnel section into a top heading and a bench, total 33 m 2 . After the last top heading round was excavated and the roof had been reinforced with fibre reinforced shotcrete the bench was taken out with horizontal holes as the third phase. The drilling precision was very good and 95% of all half-pipes fulfilled the demands. The total amount of visible half-pipes in the APSE-tunnel was high and indicated a successful smooth blasting. The EDZ was examined further by cutting slots in the wall and roof. Existing cracks appear very clearly when a dye penetrant is sprayed on the cleaned surface. A typical crack pattern consists of blast cracks, induced cracks (cracks from the distressing caused by blasting) and natural cracks. The maximum crack length in

  19. Aespoe HRL. Experiences of blasting of the TASQ tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Mats [Swebrec, Luleaa (Sweden); Niklasson, Bengt [Skanska Teknik, Stockholm (Sweden); Wilson, Lasse [Skanska Stora Projekt, Stockholm (Sweden); Andersson, Christer; Christiansson, Rolf [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2004-11-01

    A new tunnel was developed at the Aespoe Hard Rock Laboratory (AHRL) during the spring and summer 2003. The tunnel was specially designed for a rock mechanics experiment, the Aespoe Pillar Stability Experiment (APSE). In this pillar experiment there was a high demand to initiate high in-situ stresses and therefore the tunnel was designed with a large height/ width ratio and with a circular floor. There were high requirements on bore hole precision and of a minimized EDZ (Excavation damaged zone) in the pillar area. This included a maximum borehole deviation of 10 mm/m, a maximum overbreak due to the lookout angle of 0.3 m and an EDZ of 0.3 m. To make a charge control feasible cartridged explosives was prescribed. The initiation was made with Nonel. The last three rounds used electronic initiation to enable studies of possibility to further reduce the EDZ. The collar of the tunnel was very close to installations and shaft and it was very important to avoid fly-rock and vibrations. Special types of stemming were used as well as steel plates and rubber mats. The excavation works was divided in three different phases. The first phase of the tunnel was an ordinary 26 m{sup 2} tunnel. After approximately 30 m a ramp separated the tunnel section into a top heading and a bench, total 33 m{sup 2}. After the last top heading round was excavated and the roof had been reinforced with fibre reinforced shotcrete the bench was taken out with horizontal holes as the third phase. The drilling precision was very good and 95% of all half-pipes fulfilled the demands. The total amount of visible half-pipes in the APSE-tunnel was high and indicated a successful smooth blasting. The EDZ was examined further by cutting slots in the wall and roof. Existing cracks appear very clearly when a dye penetrant is sprayed on the cleaned surface. A typical crack pattern consists of blast cracks, induced cracks (cracks from the distressing caused by blasting) and natural cracks. The maximum crack

  20. ONKALO 3D tunnel seismic investigations at Olkiluoto in 2009

    International Nuclear Information System (INIS)

    Cosma, C.; Enescu, N.; Balu, L.; Jacome, M.

    2011-02-01

    attention is given for the design of the work flow. A particular task of the seismic survey carried out in the ONKALO access tunnel was to test the suitability of 2D/3D reflection seismics for detecting and locating geological features of diverse character and orientations. The results obtained by the novel 3D IP migration algorithm proved this to be a successful test. Due to the two source-line survey geometry and the use of three-component geophones, it was possible to detect fracture zones or single fractures of certain orientations up to a distance of 200 m. As with previous work performed in 2007, creating a good and detailed model (or prediction) of the geological and hydrological features of the repository area requires that integrated modeling is carried out using all geological, hydrological and geophysical data. Preliminary, tentative interpretations were done by comparing the processed seismic data with known geological, geophysical and hydrological features observed in the tunnel. From these it appears to be possible to locate known features by seismics, from site-scale (e.g. brittle fractured zones) to tunnel-scale (e.g. single long fractures). (orig.)

  1. Measures for the reduction of sinter formations in tunnels

    Science.gov (United States)

    Harer, Gerhard

    2017-09-01

    A considerable part of the maintenance costs of tunnel structures is related to the inspection, maintenance and repair of the drainage system. The drainage system of tunnels is frequently clogged with Calcium precipitates. Cleaning and water conditioning are costintensive for operating companies. Apart from the direct costs associated with inspection, maintenance and repair works of the drainage system indirect costs are generated, such as by the blocking of the tunnel while inspection, maintenance or repair or by the reduction of the permitted operation speed. Sintering and clogging of the drainage systems is mainly caused by dissolution of cement minerals in concrete and mortar and/or by inadequate design and construction of the drainage system and/or grubby workmanship. With long-term studies and in-situ experiments in Austria traffic tunnels the specific input factors for sinter mechanism have been identified and appropriate counter measures could be defined. In particular modified mix designs for shotcretes and mortars have proven to bring a significant beneficial effect. By means of constructional measures and by the application of hardness stabilizers a further reduction of hard deposits inside the drainage system is achievable. The paper will deal with the specific aspects and will propose adequate counter measures.

  2. Tunnel Face Stability & New CPT Applications

    NARCIS (Netherlands)

    Broere, W.

    2001-01-01

    Nearly all tunnels bored in soft soils have encountered problems with the stability of the tunnel face. In several cases these problems led to an extended stand-still of the boring process. A better understanding of the face stability, and of the soil conditions around the tunnel boring machine, can

  3. Defining the Anthropocene

    Science.gov (United States)

    Lewis, Simon; Maslin, Mark

    2016-04-01

    Time is divided by geologists according to marked shifts in Earth's state. Recent global environmental changes suggest that Earth may have entered a new human-dominated geological epoch, the Anthropocene. Should the Anthropocene - the idea that human activity is a force acting upon the Earth system in ways that mean that Earth will be altered for millions of years - be defined as a geological time-unit at the level of an Epoch? Here we appraise the data to assess such claims, first in terms of changes to the Earth system, with particular focus on very long-lived impacts, as Epochs typically last millions of years. Can Earth really be said to be in transition from one state to another? Secondly, we then consider the formal criteria used to define geological time-units and move forward through time examining whether currently available evidence passes typical geological time-unit evidence thresholds. We suggest two time periods likely fit the criteria (1) the aftermath of the interlinking of the Old and New Worlds, which moved species across continents and ocean basins worldwide, a geologically unprecedented and permanent change, which is also the globally synchronous coolest part of the Little Ice Age (in Earth system terms), and the beginning of global trade and a new socio-economic "world system" (in historical terms), marked as a golden spike by a temporary drop in atmospheric CO2, centred on 1610 CE; and (2) the aftermath of the Second World War, when many global environmental changes accelerated and novel long-lived materials were increasingly manufactured, known as the Great Acceleration (in Earth system terms) and the beginning of the Cold War (in historical terms), marked as a golden spike by the peak in radionuclide fallout in 1964. We finish by noting that the Anthropocene debate is politically loaded, thus transparency in the presentation of evidence is essential if a formal definition of the Anthropocene is to avoid becoming a debate about bias. The

  4. Geo electrical Resistivity Survey for Ancient Tunnel Detection at Bukit Tenggek, Setiu, Terengganu

    International Nuclear Information System (INIS)

    Siti Nazira Masrom; Mohd Hariri Arifin; Abd Rahim Harun; Abdul Rahim Samsudin

    2011-01-01

    Geo electrical resistivity survey was conducted in the Bukit Tenggek, Setiu, Terengganu to detect the possible existence of an ancient tunnel which is believed to be in the area. Geo electrical resistivity method was found very effective in searching for archaeological exploration and underground structures (tunnels and artifacts). Geo electrical resistivity survey was carried out using Terrameter ABEM SAS1000 and Wenner array electrode configuration. The survey area is located in a damp valley with a stream across the region. 2-D resistivity image showed the existence of anomalies in several areas that can be associated with the structure. Low resistivity value represents the estimated existence of the old tunnel, while isolated rounded anomalies are believed to be associated with barrels/artifacts. 3-D resistivity profiles, shows anomalies that may be caused by the existence of a horizontal and two vertical tunnels (shaft). However, the drillings work need to be done to figure out the exact cause of these anomalies. (author)

  5. Development and Evaluation of Solar Tunnel Dryer for Commercial Fish Drying

    Science.gov (United States)

    Mohod, A. G.; Khandetod, Y. P.; Shrirame, H. Y.

    2014-01-01

    The local practice of drying fish in open sun drying poses problems such as high moisture content, uncontrolled drying and contamination. These problems can be avoided by proper use of improved methods such as the solar tunnel dryer, which results in faster drying of fish. The semi cylindrical walk-in type natural convection solar tunnel dryer, having drying area of 37.5 m2 was developed and evaluated for the drying of fish products in comparison with the conventional method of open sun drying. The experiments were conducted without fish and with fish to evaluate the performance of solar tunnel dryer. The average rise in temperature inside the solar tunnel dryer was found to be 11.24 °C and 18.29 °C over the ambient temperature during no load test in winter and summer respectively. The average 28 % saving in time was observed for selected fish drying using solar tunnel dryer over open sun drying method with average drying efficiency of 19 %. The economics was calculated for drying of prawns ( Parapaeneopsis stylifera) by solar tunnel dryer and open sun drying system on the basis of business as a whole. The economics of the solar tunnel dryer is presented in term of Net present worth, Benefit-Cost Ratio, Payback period, Profitability index and Internal rate of return. The pay back period for solar tunnel dryer was found to be 2.84 years.

  6. Tunable spin-tunnel contacts to silicon using low-work-function ferromagnets

    Science.gov (United States)

    Min, Byoung-Chul; Motohashi, Kazunari; Lodder, Cock; Jansen, Ron

    2006-10-01

    Magnetic tunnel junctions have become ubiquitous components appearing in magnetic random-access memory, read heads of magnetic disk drives and semiconductor-based spin devices. Inserting a tunnel barrier has been key to achieving spin injection from ferromagnetic (FM) metals into GaAs, but spin injection into Si has remained elusive. We show that Schottky barrier formation leads to a huge conductivity mismatch of the FM tunnel contact and Si, which cannot be solved by the well-known method of adjusting the tunnel barrier thickness. We present a radically different approach for spin-tunnelling resistance control using low-work-function ferromagnets, inserted at the FM/tunnel barrier interface. We demonstrate that in this way the resistance-area (RA) product of FM/Al2O3/Si contacts can be tuned over eight orders of magnitude, while simultaneously maintaining a reasonable tunnel spin polarization. This raises prospects for Si-based spintronics and presents a new category of ferromagnetic materials for spin-tunnel contacts in low-RA-product applications.

  7. Tunneling into quantum wires: regularization of the tunneling Hamiltonian and consistency between free and bosonized fermions

    OpenAIRE

    Filippone, Michele; Brouwer, Piet

    2016-01-01

    Tunneling between a point contact and a one-dimensional wire is usually described with the help of a tunneling Hamiltonian that contains a delta function in position space. Whereas the leading order contribution to the tunneling current is independent of the way this delta function is regularized, higher-order corrections with respect to the tunneling amplitude are known to depend on the regularization. Instead of regularizing the delta function in the tunneling Hamiltonian, one may also obta...

  8. Teleology and Defining Sex.

    Science.gov (United States)

    Gamble, Nathan K; Pruski, Michal

    2018-07-01

    Disorders of sexual differentiation lead to what is often referred to as an intersex state. This state has medical, as well as some legal, recognition. Nevertheless, the question remains whether intersex persons occupy a state in between maleness and femaleness or whether they are truly men or women. To answer this question, another important conundrum needs to be first solved: what defines sex? The answer seems rather simple to most people, yet when morphology does not coincide with haplotypes, and genetics might not correlate with physiology the issue becomes more complex. This paper tackles both issues by establishing where the essence of sex is located and by superimposing that framework onto the issue of the intersex. This is achieved through giving due consideration to the biology of sexual development, as well as through the use of a teleological framework of the meaning of sex. Using a range of examples, the paper establishes that sex cannot be pinpointed to one biological variable but is rather determined by how the totality of one's biology is oriented towards biological reproduction. A brief consideration is also given to the way this situation could be comprehended from a Christian understanding of sex and suffering.

  9. Evaluation of tunnel seismic prediction (TSP) result using the Japanese highway rock mass classification system for Pahang-Selangor Raw Water Transfer Tunnel

    Science.gov (United States)

    Von, W. C.; Ismail, M. A. M.

    2017-10-01

    The knowing of geological profile ahead of tunnel face is significant to minimize the risk in tunnel excavation work and cost control in preventative measure. Due to mountainous area, site investigation with vertical boring is not recommended to obtain the geological profile for Pahang-Selangor Raw Water Transfer project. Hence, tunnel seismic prediction (TSP) method is adopted to predict the geological profile ahead of tunnel face. In order to evaluate the TSP results, IBM SPSS Statistic 22 is used to run artificial neural network (ANN) analysis to back calculate the predicted Rock Grade Points (JH) from actual Rock Grade Points (JH) using Vp, Vs and Vp/Vs from TSP. The results show good correlation between predicted Rock Grade points and actual Rock Grade Points (JH). In other words, TSP can provide geological profile prediction ahead of tunnel face significantly while allowing continuously TBM excavation works. Identifying weak zones or faults ahead of tunnel face is crucial for preventative measures to be carried out in advance for a safer tunnel excavation works.

  10. Macroscopic Refrigeration Using Superconducting Tunnel Junctions

    Science.gov (United States)

    Lowell, Peter; O'Neil, Galen; Underwood, Jason; Zhang, Xiaohang; Ullom, Joel

    2014-03-01

    Sub-kelvin temperatures are often a prerequisite for modern scientific experiments, such as quantum information processing, astrophysical missions looking for dark energy signatures and tabletop time resolved x-ray spectroscopy. Existing methods of reaching these temperatures, such as dilution refrigerators, are bulky and costly. In order to increase the accessibility of sub-Kelvin temperatures, we have developed a new method of refrigeration using normal-metal/insulator/superconductor (NIS) tunnel junctions. NIS junctions cool the electrons in the normal metal since the hottest electrons selectively tunnel from the normal metal into the superconductor. By extending the normal metal onto a thermally isolated membrane, the cold electrons can cool the phonons through the electron-phonon coupling. When these junctions are combined with a pumped 3He system, they provide a potentially inexpensive method of reaching these temperatures. Using only three devices, each with a junction area of approximately 3,500 μm2, we have cooled a 2 cm3 Cu plate from 290 mK to 256 mK. We will present these experimental results along with recent modeling predictions that strongly suggest that further refinements will allow cooling from 300 mK to 120 mK. This work is supported by the NASA APRA program.

  11. Earth Pressure on Tunnel Crown

    DEFF Research Database (Denmark)

    Andersen, Lars

    Two different analyses have been carried out in order to find the vertical earth pressure, or overburden pressure, at the crown of a tunnel going through a dike. Firstly, a hand calculation is performed using a simple dispersion of the stresses over depth. Secondly, the finite‐element program...

  12. Introduction to scanning tunneling microscopy

    CERN Document Server

    Chen, C Julian

    2008-01-01

    The scanning tunneling and the atomic force microscope, both capable of imaging individual atoms, were crowned with the Physics Nobel Prize in 1986, and are the cornerstones of nanotechnology today. This is a thoroughly updated version of this 'bible' in the field.

  13. Installation in the SPS tunnel

    CERN Multimedia

    1974-01-01

    The SPS tunnel is 6910 m in circumference and has a cross section of 4 m inner diameter. It is situated at an elevation of 400 m above sea level at a depth below the surface varying between 23 and 65 m. Its walls are lined with a concrete shell of about 30 cm thickness. See also 7410043X

  14. Principles of electron tunneling spectroscopy

    CERN Document Server

    Wolf, E L

    2012-01-01

    Electron tunnelling spectroscopy as a research tool has strongly advanced understanding of superconductivity. This book explains the physics and instrumentation behind the advances illustrated in beautiful images of atoms, rings of atoms and exotic states in high temperature superconductors, and summarizes the state of knowledge that has resulted.

  15. Time tunnels meet warped passages

    CERN Multimedia

    Kushner, David

    2006-01-01

    "Just in time for its 40th anniversary, the classic sci-fi television show "The time tunnel" is out on DVD. The conceit is something every engineer can relate to: a pulled plug. Scientists in an underground lab are working on a secret government experiment in time travel. (1 page)

  16. Zero energy Tunnel-concept

    NARCIS (Netherlands)

    Dzhusupova, R.

    2012-01-01

    Creating a zero energy environment is a hot topic. The developments in this field are based on the concept of the "Trias Energetica": reducing energy consumption, using renewable energy sources, and efficiently using fossil fuels. A zero energy concept can also be applied to road tunnels to improve

  17. Travelling inside the SPS tunnel

    CERN Multimedia

    1974-01-01

    The golf cart proved to be a very useful form of transport around the 7 km circumference of the machine. It could carry four passengers and pull light equipment in its trailer. Here Peter Zettwoch is the driver along a mock-up tunnel for installation tests. (see photo 7401011X and Photo Archive 7401018)

  18. A Seamless Ubiquitous Telehealthcare Tunnel

    Directory of Open Access Journals (Sweden)

    Sao-Jie Chen

    2013-08-01

    Full Text Available Mobile handheld devices are rapidly using to implement healthcare services around the World. Fundamentally, these services utilize telemedicine technologies. A disconnection of a mobile telemedicine system usually results in an interruption, which is embarrassing, and reconnection is necessary during the communication session. In this study, the Stream Control Transmission Protocol (SCTP is adopted to build a stable session tunnel to guarantee seamless switching among heterogeneous wireless communication standards, such as Wi-Fi and 3G. This arrangement means that the telemedicine devices will not be limited by a fixed wireless connection and can switch to a better wireless channel if necessary. The tunnel can transmit plain text, binary data, and video streams. According to the evaluation of the proposed software-based SCTP-Tunnel middleware shown, the performance is lower than anticipated and is slightly slower than a fixed connection. However, the transmission throughput is still acceptable for healthcare professionals in a healthcare enterprise or home care site. It is necessary to build more heterogeneous wireless protocols into the proposed tunnel-switching scheme to support all possible communication protocols. In addition, SCTP is another good choice for promoting communication in telemedicine and healthcare fields.

  19. Tunnel Vision in Environmental Management.

    Science.gov (United States)

    Miller, Alan

    1982-01-01

    Discusses problem-solving styles in environmental management and the specific deficiencies in these styles that might be grouped under the label "tunnel vision," a form of selective attention contributing to inadequate problem-formulation, partial solutions to complex problems, and generation of additional problems. Includes educational…

  20. Management of Carpal Tunnel Syndrome.

    Science.gov (United States)

    Mooar, Pekka A; Doherty, William J; Murray, Jayson N; Pezold, Ryan; Sevarino, Kaitlyn S

    2018-03-15

    The American Academy of Orthopaedic Surgeons (AAOS) has developed Appropriate Use Criteria (AUC) for Management of Carpal Tunnel Syndrome. Evidence-based information, in conjunction with the clinical expertise of physicians, was used to develop the criteria to improve patient care and obtain best outcomes while considering the subtleties and distinctions necessary in making clinical decisions. To provide the evidence foundation for this AUC, the AAOS Evidence-Based Medicine Unit provided the writing panel and voting panel with the 2016 AAOS Clinical Practice Guideline titled Management of Carpal Tunnel Syndrome Evidence-Based Clinical Practice Guideline. The Management of Carpal Tunnel Syndrome AUC clinical patient scenarios were derived from indications typical of patients with suspected carpal tunnel syndrome in clinical practice, as well as from current evidence-based clinical practice guidelines and supporting literature to identify the appropriateness of treatments. The 135 patient scenarios and 6 treatments were developed by the writing panel, a group of clinicians who are specialists in this AUC topic. Next, a separate, multidisciplinary, voting panel (made up of specialists and nonspecialists) rated the appropriateness of treatment of each patient scenario using a 9-point scale to designate a treatment as Appropriate (median rating, 7 to 9), May Be Appropriate (median rating, 4 to 6), or Rarely Appropriate (median rating, 1 to 3).

  1. Vulnerability Analysis of Soft Caving Tunnel Support System and Surrounding Rock Optimal Control Technology Research

    Directory of Open Access Journals (Sweden)

    Ming Ji

    2014-01-01

    Full Text Available The vulnerability assessment model, composed by 11 vulnerability factors, is established with the introduction of the concept of “vulnerability” into the assessment of tunnel support system. Analytic hierarchy process is utilized to divide these 11 factors into human attributes and natural attributes, and define the weight of these factors for the model. The “vulnerability” applied io the assessment of the tunnel support system model is reached. The vulnerability assessment model was used for evaluating and modifying the haulage tunnel #3207 of Bo-fang mine panel #2. The results decreased the vulnerability of the tunnel support system and demonstrated acceptable effects. Furthermore, the results show that the impact of human attributes on tunnel support systems is dramatic under the condition that natural attributes are permanent, and the “vulnerability” is exactly a notable factor to manifest the transformation during this process. The results also indicate that optimizing human attributes can attenuate vulnerability in tunnel support systems. As a result, enhancement of stability of tunnel support systems can be achieved.

  2. Dirac particle tunneling from black rings

    International Nuclear Information System (INIS)

    Jiang Qingquan

    2008-01-01

    Recent research shows that Hawking radiation can be treated as a quantum tunneling process, and Hawking temperatures of Dirac particles across the horizon of a black hole can be correctly recovered via the fermion tunneling method. In this paper, motivated by the fermion tunneling method, we attempt to apply the analysis to derive Hawking radiation of Dirac particles via tunneling from black ring solutions of 5-dimensional Einstein-Maxwell-dilaton gravity theory. Finally, it is interesting to find that, as in the black hole case, fermion tunneling can also result in correct Hawking temperatures for the rotating neutral, dipole, and charged black rings.

  3. Experimental Evidence for Quantum Tunneling Time

    Science.gov (United States)

    Camus, Nicolas; Yakaboylu, Enderalp; Fechner, Lutz; Klaiber, Michael; Laux, Martin; Mi, Yonghao; Hatsagortsyan, Karen Z.; Pfeifer, Thomas; Keitel, Christoph H.; Moshammer, Robert

    2017-07-01

    The first hundred attoseconds of the electron dynamics during strong field tunneling ionization are investigated. We quantify theoretically how the electron's classical trajectories in the continuum emerge from the tunneling process and test the results with those achieved in parallel from attoclock measurements. An especially high sensitivity on the tunneling barrier is accomplished here by comparing the momentum distributions of two atomic species of slightly deviating atomic potentials (argon and krypton) being ionized under absolutely identical conditions with near-infrared laser pulses (1300 nm). The agreement between experiment and theory provides clear evidence for a nonzero tunneling time delay and a nonvanishing longitudinal momentum of the electron at the "tunnel exit."

  4. Photon-phonon-enhanced infrared rectification in a two-dimensional nanoantenna-coupled tunnel diode

    International Nuclear Information System (INIS)

    Kadlec, Emil A.; Jarecki, Robert L.; Starbuck, Andrew; Peters, David W.; Davids, Paul S.

    2016-01-01

    The interplay of strong infrared photon-phonon coupling with electromagnetic confinement in nanoscale devices is demonstrated to have a large impact on ultrafast photon-assisted tunneling in metal-oxide-semiconductor (MOS) structures. Infrared active optical phonon modes in polar oxides lead to strong dispersion and enhanced electric fields at material interfaces. We find that the infrared dispersion of SiO_2 near a longitudinal optical phonon mode can effectively impedance match a photonic surface mode into a nanoscale tunnel gap that results in large transverse-field confinement. An integrated 2D nanoantenna structure on a distributed large-area MOS tunnel-diode rectifier is designed and built to resonantly excite infrared surface modes and is shown to efficiently channel infrared radiation into nanometer-scale gaps in these MOS devices. This enhanced-gap transverse-electric field is converted to a rectified tunneling displacement current resulting in a dc photocurrent. We examine the angular and polarization-dependent spectral photocurrent response of these 2D nanoantenna-coupled tunnel diodes in the photon-enhanced tunneling spectral region. Lastly, our 2D nanoantenna-coupled infrared tunnel-diode rectifier promises to impact large-area thermal energy harvesting and infrared direct detectors.

  5. Automated Boundary Conditions for Wind Tunnel Simulations

    Science.gov (United States)

    Carlson, Jan-Renee

    2018-01-01

    Computational fluid dynamic (CFD) simulations of models tested in wind tunnels require a high level of fidelity and accuracy particularly for the purposes of CFD validation efforts. Considerable effort is required to ensure the proper characterization of both the physical geometry of the wind tunnel and recreating the correct flow conditions inside the wind tunnel. The typical trial-and-error effort used for determining the boundary condition values for a particular tunnel configuration are time and computer resource intensive. This paper describes a method for calculating and updating the back pressure boundary condition in wind tunnel simulations by using a proportional-integral-derivative controller. The controller methodology and equations are discussed, and simulations using the controller to set a tunnel Mach number in the NASA Langley 14- by 22-Foot Subsonic Tunnel are demonstrated.

  6. Dynamic Tunneling Junctions at the Atomic Intersection of Two Twisted Graphene Edges.

    Science.gov (United States)

    Bellunato, Amedeo; Vrbica, Sasha D; Sabater, Carlos; de Vos, Erik W; Fermin, Remko; Kanneworff, Kirsten N; Galli, Federica; van Ruitenbeek, Jan M; Schneider, Grégory F

    2018-04-11

    The investigation of the transport properties of single molecules by flowing tunneling currents across extremely narrow gaps is relevant for challenges as diverse as the development of molecular electronics and sequencing of DNA. The achievement of well-defined electrode architectures remains a technical challenge, especially due to the necessity of high precision fabrication processes and the chemical instability of most bulk metals. Here, we illustrate a continuously adjustable tunneling junction between the edges of two twisted graphene sheets. The unique property of the graphene electrodes is that the sheets are rigidly supported all the way to the atomic edge. By analyzing the tunneling current characteristics, we also demonstrate that the spacing across the gap junction can be controllably adjusted. Finally, we demonstrate the transition from the tunneling regime to contact and the formation of an atomic-sized junction between the two edges of graphene.

  7. Semianalytical Solution and Parameters Sensitivity Analysis of Shallow Shield Tunneling-Induced Ground Settlement

    Directory of Open Access Journals (Sweden)

    Jifeng Liu

    2017-01-01

    Full Text Available The influence of boundary soil properties on tunneling-induced ground settlement is generally not considered in current analytic solutions, and the hypothesis of equal initial stress in vertical and horizontal makes the application of the above solutions limited. Based on the homogeneous half-plane hypothesis, by defining the boundary condition according to the ground loss pattern in shallow tunnel, and with the use of Mohr-Coulomb plastic yielding criteria and classic Lame and Kiersch elastic equations by separating the nonuniform stress field to uniform and single-direction stress field, a semiempirical solution for ground settlement induced by single shallow circular tunnel is presented and sensitivity to the ground parameters is analyzed. The methods of settlement control are offered by influence factors analysis of semiempirical solution. A case study in Beijing Metro tunnel shows that the semiempirical solution agrees well with the in situ measured results.

  8. Clavicular bone tunnel malposition leads to early failures in coracoclavicular ligament reconstructions.

    Science.gov (United States)

    Cook, Jay B; Shaha, James S; Rowles, Douglas J; Bottoni, Craig R; Shaha, Steven H; Tokish, John M

    2013-01-01

    Modern techniques for the treatment of acromioclavicular (AC) joint dislocations have largely centered on free tendon graft reconstructions. Recent biomechanical studies have demonstrated that an anatomic reconstruction with 2 clavicular bone tunnels more closely matches the properties of native coracoclavicular (CC) ligaments than more traditional techniques. No study has analyzed tunnel position in regard to risk of early failure. To evaluate the effect of clavicular tunnel position in CC ligament reconstruction as a risk of early failure. Case series; Level of evidence, 4. A retrospective review was performed of a consecutive series of CC ligament reconstructions performed with 2 clavicular bone tunnels and a free tendon graft. The population was largely a young, active-duty military group of patients. Radiographs were analyzed for the maintenance of reduction and location of clavicular bone tunnels using a picture archiving and communication system. The distance from the lateral border of the clavicle to the center of each bone tunnel was divided by the total clavicular length to establish a ratio. Medical records were reviewed for operative details and functional outcome. Failure was defined as loss of intraoperative reduction. The overall failure rate was 28.6% (8/28) at an average of 7.4 weeks postoperatively. Comparison of bone tunnel position showed that medialized bone tunnels were a significant predictor for early loss of reduction for the conoid (a ratio of 0.292 vs 0.248; P = .012) and trapezoid bone tunnels (a ratio of 0.171 vs 0.128; P = .004); this correlated to an average of 7 to 9 mm more medial in the reconstructions that failed. Reconstructions performed with a conoid ratio of ≥0.30 were significantly more likely to fail (5/5, 100%) than were those performed lateral to a ratio of 0.30 (3/23, 13.0%) (P < .01). There were no failures when the conoid ratio was <0.25 (0/10, 0%). Conoid tunnel placement was also statistically significant for

  9. Blade-Element/Momentum Technique for Rotors operating in Wind Tunnels

    DEFF Research Database (Denmark)

    Sørensen, Jens Nørkær; Sørensen, Dan Nørtoft

    2003-01-01

    small, since important properties of the blade boundary layer otherwise cannot be captured correctly. On the other hand, severe problems with wind tunnel blockage may be the result if the ratio between the areas of the rotor and the wind tunnel cross section is too big. In all cases, wind tunnel...... wallcorrections are needed in order that measured data corresponds to unconstrained flow conditions. The present work is based on a model for ducted axial fans by Sørensen and Sørensen [5], modified to account for free (unbounded) turbines [6]. Here, we extend the model to acount for wind turbines placed in wind...

  10. Resonant tunneling of spin-wave packets via quantized states in potential wells.

    Science.gov (United States)

    Hansen, Ulf-Hendrik; Gatzen, Marius; Demidov, Vladislav E; Demokritov, Sergej O

    2007-09-21

    We have studied the tunneling of spin-wave pulses through a system of two closely situated potential barriers. The barriers represent two areas of inhomogeneity of the static magnetic field, where the existence of spin waves is forbidden. We show that for certain values of the spin-wave frequency corresponding to the quantized spin-wave states existing in the well formed between the barriers, the tunneling has a resonant character. As a result, transmission of spin-wave packets through the double-barrier structure is much more efficient than the sequent tunneling through two single barriers.

  11. Resonant tunnel magnetoresistance in a double magnetic tunnel junction

    KAUST Repository

    Useinov, Arthur

    2011-08-09

    We present quasi-classical approach to calculate a spin-dependent current and tunnel magnetoresistance (TMR) in double magnetic tunnel junctions (DMTJ) FML/I/FMW/I/FMR, where the magnetization of the middle ferromagnetic metal layer FMW can be aligned parallel or antiparallel with respect to the fixed magnetizations of the left FML and right FMR ferromagnetic electrodes. The transmission coefficients for components of the spin-dependent current, and TMR are calculated as a function of the applied voltage. As a result, we found a high resonant TMR. Thus, DMTJ can serve as highly effective magnetic nanosensor for biological applications, or as magnetic memory cells by switching the magnetization of the inner ferromagnetic layer FMW.© Springer Science+Business Media, LLC 2011.

  12. Definably compact groups definable in real closed fields.II

    OpenAIRE

    Barriga, Eliana

    2017-01-01

    We continue the analysis of definably compact groups definable in a real closed field $\\mathcal{R}$. In [3], we proved that for every definably compact definably connected semialgebraic group $G$ over $\\mathcal{R}$ there are a connected $R$-algebraic group $H$, a definable injective map $\\phi$ from a generic definable neighborhood of the identity of $G$ into the group $H\\left(R\\right)$ of $R$-points of $H$ such that $\\phi$ acts as a group homomorphism inside its domain. The above result and o...

  13. Tunnel boring an alternative method in construction of spent fuel repositories

    International Nuclear Information System (INIS)

    Christersson, Jukka

    1984-05-01

    In projecting of the final disposal of nuclear waste in geological formations a great importance should be paid to the selection of the tunneling method. The environment of the chosen repository area should not be exposed to any but as minor disturbances as possible by the excavation method applied. This study approaches full face tunneling methods as an alternative to conventional drill-and-blast methods in the construction of spent fuel repository tunnels. According to experiences up till now it is obvious, that tunnelboring today is fully capable technically competing with conventional tunneling methods, even in the hardest granitic rocks. The most important advantages, it provides for the construction of repositories, are: The methods does not produce any damage in the surrounding rock. Possibility to use placement techniques, which do not require preparing of additive repository holes for the fuel elements. Saving in the use of expensive filling material. The fact, that tunnel boring in hard rock is an expensive alternative, is still valid. Constuction of straight lined tunnels in unfractured rocks by tunnel boring would cost about 30-40% more than by conventional methods. The lay out arrangement of bored tunnels still have a great influence on tunnel boring machine's economy. Due to this it would be round 40-70% more expensive method in the construction of spent fuel repositories. However intensive development w is being carried out to eliminate these limitations and to make machines more flexible. Future trends in tunnel boring look good at the moment. The number of sold units has been increasing and new applications have widen out during last ten years. Harder and more abrasive rocks can now be bored than ever before and the trend seems to continue. It also looks like the cost difference in the hardest rocks is firmly getting smaller and smaller all the time. (author)

  14. The anatomy and histology of the bicipital tunnel of the shoulder.

    Science.gov (United States)

    Taylor, Samuel A; Fabricant, Peter D; Bansal, Manjula; Khair, M Michael; McLawhorn, Alexander; DiCarlo, Edward F; Shorey, Mary; O'Brien, Stephen J

    2015-04-01

    The bicipital tunnel is the extra-articular, fibro-osseous structure that encloses the long head of the biceps tendon. Twelve cadaveric shoulder specimens underwent in situ casting of the bicipital tunnel with methyl methacrylate cement to demonstrate structural competence (n = 6) and en bloc harvest with gross and histologic evaluation (n = 6). The percentage of empty tunnel was calculated histologically by subtracting the proportion of cross-sectional area of the long head of the biceps tendon from that of the bicipital tunnel for each zone. Cement casting demonstrated that the bicipital tunnel was a closed space. Zone 1 extended from the articular margin to the distal margin of the subscapularis tendon. Zone 2 extended from the distal margin of the subscapularis tendon to the proximal margin of the pectoralis major tendon. Zone 3 was the subpectoral region. Zones 1 and 2 were both enclosed by a dense connective tissue sheath and demonstrated the presence of synovium. Zone 3 had significantly greater percentage of empty tunnel than zones 1 and 2 did (P < .01). The bicipital tunnel is a closed space with 3 distinct zones. Zones 1 and 2 have similar features, including the presence of synovium, but differ from zone 3. A significant bottleneck occurs between zone 2 and zone 3, most likely at the proximal margin of the pectoralis major tendon. The bicipital tunnel is a closed space where space-occupying lesions may produce a bicipital tunnel syndrome. Careful consideration should be given to surgical techniques that decompress both zones 1 and 2 of the bicipital tunnel. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  15. Rock mass evaluation for predicting tunnel constructability in the preliminary investigation stage. Phenomena causing difficult tunneling and rockburst prediction

    International Nuclear Information System (INIS)

    Shin, Koichi; Sawada, Masataka; Inohara, Yoshiki; Shidahara, Takumi; Hatano, Teruyoshi

    2011-01-01

    For the selection of the Detailed Investigation Areas for HLW disposal, predicting the tunnel constructability is one of the requirements together with assessing long-term safety. This report is the 1st of the three papers dealing with the evaluation of tunnel constructability. This paper deals with the geological factors relating to difficult tunneling such as squeezing, rockburst, and others. Also it deals with the prediction of rockburst. The 2nd paper will deal with the prediction of squeezing. The 3rd paper deals with the engineering characteristics of rock mass through rock mass classification. This paper about difficult tunneling has been based upon analysis of more than 500 tunneling reports about 280 tunnel constructions. The causes of difficult tunneling are related to (1) underground water, (2) mechanical properties of the rock, or (3) others such as gas. The geological factors for excessive water inflow are porous volcanic product of Quarternary, fault crush zone and hydrothermally altered zone of Green Tuff area, and degenerated mixed rock in accretionary complex. The geological factors for squeezing are solfataric clay at Quarternary volcanic zone, fault crush zone and hydrothermally altered zone of Green Tuff area, mudstone and fault crush zone of sedimentary rock of Neogene and later. Information useful for predicting rockburst has been gathered from previous reports. In the preliminary investigation stage, geological survey, geophysical survey and borehole survey from the surface are the source of information. Therefore rock type, P-wave velocity from seismic exploration and in-situ rock stress from hydrofracturing have been considered. Majority of rockburst events occurred at granitic rock, excluding coal mine where different kind of rockburst occurred at pillars. And P-wave velocity was around 5 km/s at the rock of rockburst events. Horizontal maximum and minimum stresses SH and Sh have been tested as a criterion for rockburst. It has been

  16. The Third Quantization: To Tunnel or Not to Tunnel?

    Directory of Open Access Journals (Sweden)

    Mariam Bouhmadi-López

    2018-02-01

    Full Text Available Within the framework of the third quantization, we consider the possibility that an initially recollapsing baby universe can enter a stage of near de Sitter inflation by tunnelling through a Euclidean wormhole that connects the recollapsing and inflationary geometries. We present the solutions for the evolution of the scale factor in the Lorentzian and Euclidean regions as well as the probability that the baby universe indeed crosses the wormhole when it reaches its maximum size.

  17. The Feasibility of Multiscale Modeling of Tunnel Fires Using FDS 6

    DEFF Research Database (Denmark)

    Vermesi, Izabella; Colella, Francesco; Rein, Guillermo

    2014-01-01

    The HVAC component of FDS 6 was used to divide a 1.2km tunnel into a 3D near fire area and a 1D area further away from the fire in order to investigate the feasibility of multiscale modeling of tunnel fires with this new feature in FDS. The two sub-models were coupled directly. The results were...... compared with reference works on multiscale modeling and the outcome is considered positive, with a deviation of less than 5% in magnitude of relevant parameters, yet with a significant reduction of the simulation runtime. As such, the multiscale method is deemed feasible for simulating tunnel fires in FDS......6. However, the simplifications that are made in this work require further investigation in order to take full advantage of the potential of this computational method. INTRODUCTION Multiscale modeling for tunnel flows and fires has previously been studied using RANS general purpose CFD software...

  18. Investigations of the structure of Nb-NbO/sub x/-Pb Josephson tunnel elements

    International Nuclear Information System (INIS)

    Koehler, H.J.; Seidel, P.; Weber, P.; Bluethner, K.; Linke, S.; Haedrich, T.; Berthel, K.H.

    1983-01-01

    Nb-NbO/sub x/-Pb tunnel junctions with tunnel areas of 100x100 μm 2 to 3x3 μm 2 are investigated. The temperature dependence of the current-voltage characteristic, of the effective niobium energy gap and of the critical Josephson current are compared with the BCS curves. The deviation of the experimentally determined values is caused by a proximity layer. With a proximity effect model the parameters of this proximity layer can be found by fitting the calculated values to the experimental values. Moreover, current density distribution in tunnel junctions are determined, which can be calculated from the dependence of the critical Josephson current on the magnetic field by means of a theoretical model. The dependences of the current density distributions on tunnel areas and the changes in time are investigated. (author)

  19. Recovering information of tunneling spectrum from weakly isolated horizon

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ge-Rui; Huang, Yong-Chang [Beijing University of Technology, Institute of Theoretical Physics, Beijing (China)

    2015-02-01

    In this paper we investigate the properties of tunneling spectrum from weakly isolated horizon (WIH) - a locally defined black hole. We find that there exist correlations among Hawking radiations from a WIH, information can be carried out by such correlations, and the radiation is an entropy conservation process. Through revisiting the calculation of the tunneling spectrum from a WIH, we find that Zhang et al.'s (Ann Phys 326:350, 2011) requirement that radiated particles have the same angular momenta of a unit mass as that of the black hole is unnecessary, and the energy and angular momenta of the emitted particles are very arbitrary, restricted only by keeping the cosmic censorship hypothesis of black holes. So we resolve the information loss paradox based on the method of Zhang et al. (Phys Lett B 675:98, 2009; Ann Phys 326:350, 2011; Int J Mod Phys D 22:1341014, 2013) in a general case. (orig.)

  20. Tenosynovial osteochondromatosis of the tarsal tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Kazuya; Iwai, Makoto [Department of Orthopaedic Surgery, Saiseikai Nara Hospital, 4-643 Hachijo, Nara-shi, Nara (Japan); Kawate, Kenji; Yajima, Hiroshi; Takakura, Yoshinori [Department of Orthopaedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara-shi, Nara (Japan)

    2003-02-01

    A case of tenosynovial osteochondromatosis in the tarsal tunnel in a 23-year-old man is presented. The lesion was treated surgically, and multiple osteochondromas were excised, which had no continuity with any tarsal bone or joint cavity but did with the sheaths of the flexor digitorum longus and flexor hallucis longus. Histologic examination of the lesion showed a fibrous capsule, hyaline cartilage and extensive areas of cancellous bone. Necrosis and mitosis were absent in the hyaline cartilage and there were no synovial nodules indicative of synovial metaplasia. The macroscopic findings showed ''end-stage'' tenosynovial osteochondromatosis. There was no evidence of recurrence 5 years after operation, and the patient remains free of symptoms. (orig.)

  1. A Historical Evaluation of the U16a Tunnel, Nevada National Security Site, Nye County, Nevada Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Roberrt C. [Desert Research Inst. (DRI), Reno, NV (United States); Drollinger, Harold [Desert Research Inst. (DRI), Reno, NV (United States)

    2013-06-01

    This report presents a historical evaluation of the U16a Tunnel on the Nevada National Security Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency. The U16a Tunnel was used for underground nuclear weapons effects tests in Shoshone Mountain in Area 16 of the Nevada National Security Site. Six nuclear tests were conducted in the U16a Tunnel from 1962 to 1971. These tests are Marshmallow, Gum Drop, Double Play, Ming Vase, Diamond Dust, and Diamond Mine. The U.S. Department of Defense Threat Reduction Agency, with participation from Lawrence Livermore National Laboratory and Las Alamos National Laboratory, sponsored the tests. Fifteen high explosives tests were also conducted at the tunnel. Two were calibration tests during nuclear testing and the remaining were U.S. Department of Defense, Defense Threat Reduction Agency tunnel defeat tests. The U16a Tunnel complex is on the top and slopes of Shoshone Mountain, encompassing an area of approximately 16.7 hectares (41.1 acres). Major modifications to the landscape are a result of three principal activities, road construction and maintenance, mining activities related to development of the tunnel complex, and site preparation for activities related to testing. Forty-seven cultural features were recorded at the portal and on the slopes of Shoshone Mountain. At the portal area, features relate to the mining, construction, testing, and general every day operational support activities within the tunnel. These include concrete foundations for buildings, equipment pads, and rail lines. Features on the slopes above the tunnel relate to tunnel ventilation, borehole drilling, and data recording. Feature types include soil-covered bunkers, concrete foundations, instrument cable holes, drill holes, and ventilation shafts. The U16

  2. A Historical Evaluation of the U16a Tunnel, Nevada National Security Site, Nye County, Nevada Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Robert C. [Desert Research Inst. (DRI), Reno, NV (United States); Drollinger, Harold [Desert Research Inst. (DRI), Reno, NV (United States); Bullard, Thomas F. [Desert Research Inst. (DRI), Reno, NV (United States); Ashbaugh, Laurence J. [Desert Research Inst. (DRI), Reno, NV (United States); Griffin, Wayne R. [Desert Research Inst. (DRI), Reno, NV (United States)

    2013-01-01

    This report presents a historical evaluation of the U16a Tunnel on the Nevada National Security Site in southern Nevada. The work was conducted by the Desert Research Institute at the request of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the U.S. Department of Defense, Defense Threat Reduction Agency. The U16a Tunnel was used for underground nuclear weapons effects tests in Shoshone Mountain in Area 16 of the Nevada National Security Site. Six nuclear tests were conducted in the U16a Tunnel from 1962 to 1971. These tests are Marshmallow, Gum Drop, Double Play, Ming Vase, Diamond Dust, and Diamond Mine. The U.S. Department of Defense Threat Reduction Agency, with participation from Lawrence Livermore National Laboratory and Las Alamos National Laboratory, sponsored the tests. Fifteen high explosives tests were also conducted at the tunnel. Two were calibration tests during nuclear testing and the remaining were U.S. Department of Defense, Defense Threat Reduction Agency tunnel defeat tests. The U16a Tunnel complex is on the top and slopes of Shoshone Mountain, encompassing an area of approximately 16.7 hectares (41.1 acres). Major modifications to the landscape are a result of three principal activities, road construction and maintenance, mining activities related to development of the tunnel complex, and site preparation for activities related to testing. Forty-seven cultural features were recorded at the portal and on the slopes of Shoshone Mountain. At the portal area, features relate to the mining, construction, testing, and general every day operational support activities within the tunnel. These include concrete foundations for buildings, equipment pads, and rail lines. Features on the slopes above the tunnel relate to tunnel ventilation, borehole drilling, and data recording. Feature types include soil-covered bunkers, concrete foundations, instrument cable holes, drill holes, and ventilation shafts. The U16

  3. Water Inrush Analysis of the Longmen Mountain Tunnel Based on a 3D Simulation of the Discrete Fracture Network

    Science.gov (United States)

    Xiong, Ziming; Wang, Mingyang; Shi, ShaoShuai; Xia, YuanPu; Lu, Hao; Bu, Lin

    2017-12-01

    The construction of tunnels and underground engineering in China has developed rapidly in recent years in both the number and the length of tunnels. However, with the development of tunnel construction technology, risk assessment of the tunnels has become increasingly important. Water inrush is one of the most important causes of engineering accidents worldwide, resulting in considerable economic and environmental losses. Accordingly, water inrush prediction is important for ensuring the safety of tunnel construction. Therefore, in this study, we constructed a three-dimensional discrete network fracture model using the Monte Carlo method first with the basic data from the engineering geological map of the Longmen Mountain area, the location of the Longmen Mountain tunnel. Subsequently, we transformed the discrete fracture networks into a pipe network model. Next, the DEM of the study area was analysed and a submerged analysis was conducted to determine the water storage area. Finally, we attempted to predict the water inrush along the Longmen Mountain tunnel based on the Darcy flow equation. Based on the contrast of water inrush between the proposed approach, groundwater dynamics and precipitation infiltration method, we conclude the following: the water inflow determined using the groundwater dynamics simulation results are basically consistent with those in the D2K91+020 to D2K110+150 mileage. Specifically, in the D2K91+020 to D2K94+060, D2K96+440 to D2K98+100 and other sections of the tunnel, the simulated and measured results are in close agreement and show that this method is effective. In general, we can predict the water inflow in the area of the Longmen Mountain tunnel based on the existing fracture joint parameters and the hydrogeological data of the Longmen Mountain area, providing a water inrush simulation and guiding the tunnel excavation and construction stages.

  4. Seismic scanning tunneling macroscope - Theory

    KAUST Repository

    Schuster, Gerard T.

    2012-09-01

    We propose a seismic scanning tunneling macroscope (SSTM) that can detect the presence of sub-wavelength scatterers in the near-field of either the source or the receivers. Analytic formulas for the time reverse mirror (TRM) profile associated with a single scatterer model show that the spatial resolution limit to be, unlike the Abbe limit of λ/2, independent of wavelength and linearly proportional to the source-scatterer separation as long as the point scatterer is in the near-field region; if the sub-wavelength scatterer is a spherical impedance discontinuity then the resolution will also be limited by the radius of the sphere. Therefore, superresolution imaging can be achieved as the scatterer approaches the source. This is analogous to an optical scanning tunneling microscope that has sub-wavelength resolution. Scaled to seismic frequencies, it is theoretically possible to extract 100 Hz information from 20 Hz data by imaging of near-field seismic energy.

  5. Single-contact tunneling thermometry

    Science.gov (United States)

    Maksymovych, Petro

    2016-02-23

    A single-contact tunneling thermometry circuit includes a tunnel junction formed between two objects. Junction temperature gradient information is determined based on a mathematical relationship between a target alternating voltage applied across the junction and the junction temperature gradient. Total voltage measured across the junction indicates the magnitude of the target alternating voltage. A thermal gradient is induced across the junction. A reference thermovoltage is measured when zero alternating voltage is applied across the junction. An increasing alternating voltage is applied while measuring a thermovoltage component and a DC rectification voltage component created by the applied alternating voltage. The target alternating voltage is reached when the thermovoltage is nullified or doubled by the DC rectification voltage depending on the sign of the reference thermovoltage. Thermoelectric current and current measurements may be utilized in place of the thermovoltage and voltage measurements. The system may be automated with a feedback loop.

  6. Spin tunneling in magnetic molecules

    Science.gov (United States)

    Kececioglu, Ersin

    In this thesis, we will focus on spin tunneling in a family of systems called magnetic molecules such as Fe8 and Mn12. This is comparatively new, in relation to other tunneling problems. Many issues are not completely solved and/or understood yet. The magnetic molecule Fe 8 has been observed to have a rich pattern of degeneracies in its magnetic spectrum. We focus on these degeneracies from several points of view. We start with the simplest anisotropy Hamiltonian to describe the Fe 8 molecule and extend our discussion to include higher order anisotropy terms. We give analytical expressions as much as we can, for the degeneracies in the semi-classical limit in both cases. We reintroduce jump instantons to the instanton formalism. Finally, we discuss the effect of the environment on the molecule. Our results, for all different models and techniques, agree well with both experimental and numerical results.

  7. Tunneling magnetoresistance in Si nanowires

    KAUST Repository

    Montes Muñoz, Enrique

    2016-11-09

    We investigate the tunneling magnetoresistance of small diameter semiconducting Si nanowires attached to ferromagnetic Fe electrodes, using first principles density functional theory combined with the non-equilibrium Green\\'s functions method for quantum transport. Silicon nanowires represent an interesting platform for spin devices. They are compatible with mature silicon technology and their intrinsic electronic properties can be controlled by modifying the diameter and length. Here we systematically study the spin transport properties for neutral nanowires and both n and p doping conditions. We find a substantial low bias magnetoresistance for the neutral case, which halves for an applied voltage of about 0.35 V and persists up to 1 V. Doping in general decreases the magnetoresistance, as soon as the conductance is no longer dominated by tunneling.

  8. Seismic scanning tunneling macroscope - Theory

    KAUST Repository

    Schuster, Gerard T.; Hanafy, Sherif M.; Huang, Yunsong

    2012-01-01

    We propose a seismic scanning tunneling macroscope (SSTM) that can detect the presence of sub-wavelength scatterers in the near-field of either the source or the receivers. Analytic formulas for the time reverse mirror (TRM) profile associated with a single scatterer model show that the spatial resolution limit to be, unlike the Abbe limit of λ/2, independent of wavelength and linearly proportional to the source-scatterer separation as long as the point scatterer is in the near-field region; if the sub-wavelength scatterer is a spherical impedance discontinuity then the resolution will also be limited by the radius of the sphere. Therefore, superresolution imaging can be achieved as the scatterer approaches the source. This is analogous to an optical scanning tunneling microscope that has sub-wavelength resolution. Scaled to seismic frequencies, it is theoretically possible to extract 100 Hz information from 20 Hz data by imaging of near-field seismic energy.

  9. Tunneling of a coupled system

    International Nuclear Information System (INIS)

    Avishai, Y.

    1985-01-01

    We consider tunneling through a potential barrier V(x) in the presence of a coupling term W(x,y). Let H(y) be the internal Hamiltonian associated with the coordinate y and let E 0 (x) be the ground state energy of the operator H(x;y) = H(y) + W(x,y) in which x is a parameter. Our result for the tunneling probability (in the WKB approximation) is P = exp(2i ∫ k 0 (x)dx) where, at energy E, k 0 (x) = [E-E 0 (x)-V(x)]sup(1/2)/(h/2π) is the local wave number in the presence of coupling. (orig.)

  10. Characterization of a new open jet wind tunnel to optimize and test vertical axis wind turbines

    DEFF Research Database (Denmark)

    Tourn, Silvana; Pallarès, Jordi; Cuesta, Ildefonso

    2017-01-01

    Based on the increasing interest in urban environmental technologies, the study of small scale vertical axis wind turbines shows motivating challenges. In this paper, we present the characteristics and potentials of a new open jet wind tunnel. It has a nozzle exit area of 1.5 × 1.5 m2, and it can......%. The detailed characterization of the flow carried out indicates that the wind tunnel can be used to test small scale models of wind turbines....

  11. Development and trial measurement of synchrotron-radiation-light-illuminated scanning tunneling microscope

    International Nuclear Information System (INIS)

    Matsushima, Takeshi; Okuda, Taichi; Eguchi, Toyoaki; Ono, Masanori; Harasawa, Ayumi; Wakita, Takanori; Kataoka, Akira; Hamada, Masayuki; Kamoshida, Atsushi; Hasegawa, Yukio; Kinoshita, Toyohiko

    2004-01-01

    Scanning tunneling microscope (STM) study is performed under synchrotron-radiation-light illumination. The equipment is designed so as to achieve atomic resolution even under rather noisy conditions in the synchrotron radiation facility. By measuring photoexcited electron current by the STM tip together with the conventional STM tunneling current, Si 2p soft-x-ray absorption spectra are successfully obtained from a small area of Si(111) surface. The results are a first step toward realizing a new element-specific microscope

  12. Seismic prediction ahead of tunnel constructions

    Science.gov (United States)

    Jetschny, S.; Bohlen, T.; Nil, D. D.; Giese, R.

    2007-12-01

    To increase safety and efficiency of tunnel constructions, online seismic exploration ahead of a tunnel can become a valuable tool. Within the \\it OnSite project founded by the BMBF (German Ministry of Education and Research) within \\it GeoTechnologien a new forward looking seismic imaging technique is developed to e.g. determine weak and water bearing zones ahead of the constructions. Our approach is based on the excitation and registration of \\it tunnel surface waves. These waves are excited at the tunnel face behind the cutter head of a tunnel boring machine and travel into drilling direction. Arriving at the front face they generate body waves (mainly S-waves) propagating further ahead. Reflected S-waves are back- converted into tunnel surface waves. For a theoretical description of the conversion process and for finding optimal acquisition geometries it is of importance to study the propagation characteristics of tunnel surface waves. 3D seismic finite difference modeling and analytic solutions of the wave equation in cylindric coordinates revealed that at higher frequencies, i.e. if the tunnel diameter is significantly larger than the wavelength of S-waves, these surface waves can be regarded as Rayleigh-waves circulating the tunnel. For smaller frequencies, i.e. when the S-wavelength approaches the tunnel diameter, the propagation characteristics of these surface waves are then similar to S- waves. Field measurements performed by the GeoForschungsZentrum Potsdam, Germany at the Gotthard Base Tunnel (Switzerland) show both effects, i.e. the propagation of Rayleigh- and body-wave like waves along the tunnel. To enhance our understanding of the excitation and propagation characteristics of tunnel surface waves the transition of Rayleigh to tube-waves waves is investigated both analytically and by numerical simulations.

  13. Radon hazard from caisson and tunnel construction in Kong Kong

    International Nuclear Information System (INIS)

    Lam, W.K.; Tsin, T.W.; Ng, T.P.

    1988-01-01

    A possible occupational risk of caisson and tunnel excavation in Hong Kong results from the inhalation of natural radon daughters. In this study radon daughter concentrations ranging from 0.001 to 71.4 WL were recorded in caissons of various dimensions and from 0.03 to 0.95 WL in tunnels over 1 km in length under construction (ICRP exposure limit being 0.4 WL). There was clear indication of increased radon daughter accumulation in confined and unventilated areas and in unventilated caissons an exponential increase of radon daughter concentration with the ratio of depth to cross-sectional area was observed (r=0.9). The study revealed a potential radiation hazard facing underground construction workers and this is being examined by an ongoing epidemiological cohort study: meanwhile environmental control should be improved. (UK)

  14. Digging the CNGS decay tunnel

    CERN Multimedia

    Patrice Loiez

    2002-01-01

    Products of the collision between a proton beam and a graphite target will pass through a horn containing an electric field that will produce a focused beam. These particles will decay into muon neutrinos within the tunnel that is being constructed in these images. The neutrinos will then travel 730 km to Gran Sasso in Italy where huge detectors will observe the beam to study a process called neutrino oscillation.

  15. Dissipative Effect and Tunneling Time

    Directory of Open Access Journals (Sweden)

    Samyadeb Bhattacharya

    2011-01-01

    Full Text Available The quantum Langevin equation has been studied for dissipative system using the approach of Ford et al. Here, we have considered the inverted harmonic oscillator potential and calculated the effect of dissipation on tunneling time, group delay, and the self-interference term. A critical value of the friction coefficient has been determined for which the self-interference term vanishes. This approach sheds new light on understanding the ion transport at nanoscale.

  16. Variability in ACL tunnel placement: observational clinical study of surgeon ACL tunnel variability.

    Science.gov (United States)

    Wolf, Brian R; Ramme, Austin J; Wright, Rick W; Brophy, Robert H; McCarty, Eric C; Vidal, Armando R; Parker, Richard D; Andrish, Jack T; Amendola, Annunziato

    2013-06-01

    Multicenter and multisurgeon cohort studies on anterior cruciate ligament (ACL) reconstruction are becoming more common. Minimal information exists on intersurgeon and intrasurgeon variability in ACL tunnel placement. Purpose/ The purpose of this study was to analyze intersurgeon and intrasurgeon variability in ACL tunnel placement in a series of The Multicenter Orthopaedic Outcomes Network (MOON) ACL reconstruction patients and in a clinical cohort of ACL reconstruction patients. The hypothesis was that there would be minimal variability between surgeons in ACL tunnel placement. Cross-sectional study; Level of evidence, 3. Seventy-eight patients who underwent ACL reconstruction by 8 surgeons had postoperative imaging with computed tomography, and ACL tunnel location and angulation were analyzed using 3-dimensional surface processing and measurement. Intersurgeon and intrasurgeon variability in ACL tunnel placement was analyzed. For intersurgeon variability, the range in mean ACL femoral tunnel depth between surgeons was 22%. For femoral tunnel height, there was a 19% range. Tibial tunnel location from anterior to posterior on the plateau had a 16% range in mean results. There was only a small range of 4% for mean tibial tunnel location from the medial to lateral dimension. For intrasurgeon variability, femoral tunnel depth demonstrated the largest ranges, and tibial tunnel location from medial to lateral on the plateau demonstrated the least variability. Overall, surgeons were relatively consistent within their own cases. Using applied measurement criteria, 85% of femoral tunnels and 90% of tibial tunnels fell within applied literature-based guidelines. Ninety-one percent of the axes of the femoral tunnels fell within the boundaries of the femoral footprint. The data demonstrate that surgeons performing ACL reconstructions are relatively consistent between each other. There is, however, variability of average tunnel placement up to 22% of mean condylar depth

  17. Current-induced magnetization switching in atom-thick tungsten engineered perpendicular magnetic tunnel junctions with large tunnel magnetoresistance.

    Science.gov (United States)

    Wang, Mengxing; Cai, Wenlong; Cao, Kaihua; Zhou, Jiaqi; Wrona, Jerzy; Peng, Shouzhong; Yang, Huaiwen; Wei, Jiaqi; Kang, Wang; Zhang, Youguang; Langer, Jürgen; Ocker, Berthold; Fert, Albert; Zhao, Weisheng

    2018-02-14

    Perpendicular magnetic tunnel junctions based on MgO/CoFeB structures are of particular interest for magnetic random-access memories because of their excellent thermal stability, scaling potential, and power dissipation. However, the major challenge of current-induced switching in the nanopillars with both a large tunnel magnetoresistance ratio and a low junction resistance is still to be met. Here, we report spin transfer torque switching in nano-scale perpendicular magnetic tunnel junctions with a magnetoresistance ratio up to 249% and a resistance area product as low as 7.0 Ω µm 2 , which consists of atom-thick W layers and double MgO/CoFeB interfaces. The efficient resonant tunnelling transmission induced by the atom-thick W layers could contribute to the larger magnetoresistance ratio than conventional structures with Ta layers, in addition to the robustness of W layers against high-temperature diffusion during annealing. The critical switching current density could be lower than 3.0 MA cm -2 for devices with a 45-nm radius.

  18. 3rd May 2009 - Japanese Minister of State for Science and Technology Policy, Food Safety, Minister of Consumer Affairs, Minister of Space Policy S. Noda, visiting ATLAS experimental area, LHC tunnel and CERN Control Centre with CERN Director-General R. Heuer, Collaboration Spokesperson F. Gianotti and Beams Department Head P. Collier.

    CERN Document Server

    Maximilien Brice

    2009-01-01

    090506101-08: signature of the guest book and exchange of gifts; 090506109 + 46-64: Japanese Ambassador to the United Nations Office S. Kitajima, Japanese Minister of State for Science and Technology Policy, Food Safety, Minister of Consumer Affairs, Minister of Space Policy S. Noda, CERN Director-General R. Heuer, Non Member-State relations Adviser J. Ellis and ATLAS Collaboration Spokesperson F. Gianotti visiting the LHC tunnel at Point 1; 090506110-11 + 28-45: Japanese Minister of State for Science and Technology Policy, Food Safety, Minister of Consumer Affairs, Minister of Space Policy S. Noda and his delegation visiting ATLAS experimental area with CERN Japanese users and Management; 090506112 + 86-94: Japanese Minister of State for Science and Technology Policy, Food Safety, Minister of Consumer Affairs, Minister of Space Policy S. Noda, CERN Director-General R. Heuer and Japanese users in front of an LHC superconducting magnet; sLHC Project Leader also present. 090506113-19: Arrival of Japanese Min...

  19. THE ULTIMATE STATE CONCEPT APPLIED TO TUNNEL SUPPORT

    Directory of Open Access Journals (Sweden)

    Mladen Hudec

    2000-12-01

    Full Text Available The most questionable are the values of pressures between rock and support resulting from common deformations on the contact area between rock and support. Therefore the modelling and design of the tunnel support is not reliable, if it is based on active rock pressure resulting from this common deformations. The inversion of the design procedure is proposed. Instead of the active extreme pressure of the rock on support, the influence of ultimate reaction of the support on the rock has to be analysed. This procedure can be performed using the ultimate load principle, as proposed by Eurocodc 7 (Geotechnies. Normally, the rock has the tendency to increase the common conver¬gence until the support reaches its ultimate state. So, loading of profile boundary with the ultimate possible reaction of the support is very plausible. The reactive support pressures have to be probable and itself in equilibrium. The ultimate reactive load has to be reduced by Euro-code safety factor for structural elements and applied on the rock with given properties, or alternatively (as proposed by Eurocode 7 the soil or rock properties have to be diminished and calculated with full ultimate support pressures. If the rock with given (or proposed pro¬perties and loaded with ultimate reactive pressures resulting from supposed support, satisfy its failure criterion, then is the compound system support-rock verificatcd. By this procedure, the number of relevant material properties is reduce to the primary stress ratio and the constants defining the failure criterion. The verification can be performed by any of numerical methods, but we prefer here used boundary elements method (the paper is published in Croatian.

  20. Entropy correction of BTZ black holes in a tunneling framework

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, using the Parikh-Wilczek tunneling framework, we first calculate the emission rates of non-rotating BTZ black holes and rotating BTZ black holes to second order accuracy. Then, by assuming that the emission process satisfies an underlying unitary theory, we obtain the corrected entropy of the BTZ black holes. A log term emerges naturally in the expression of the corrected entropy. A discussion about the inverse area term is also presented.

  1. Scanning tunneling microscopy: A powerful tool for surface analysis

    International Nuclear Information System (INIS)

    Walle, G.F.A. van de; Nelissen, B.J.; Soethout, L.L.; Kempen, H. van

    1987-01-01

    The invention of the Scanning Tunneling Microscope (STM) has opened a new area of surface analysis. A description of the principle of operation is given in this paper. Also the technical problems encountered and their solution are described. Two examples demonstrating the possibilities of the STM are presented: topographic and spectroscopic measurements on a stepped Ni (111) surface and photoconductive measurements on GaAs. (orig.)

  2. Two-step tunneling technique of deep brain stimulation extension wires-a description.

    Science.gov (United States)

    Fontaine, Denys; Vandersteen, Clair; Saleh, Christian; von Langsdorff, Daniel; Poissonnet, Gilles

    2013-12-01

    While a significant body of literature exists on the intracranial part of deep brain stimulation surgery, the equally important second part of the intervention related to the subcutaneous tunneling of deep brain stimulation extension wires is rarely described. The tunneling strategy can consist of a single passage of the extension wires from the frontal incision site to the subclavicular area, or of a two-step approach that adds a retro-auricular counter-incision. Each technique harbors the risk of intraoperative and postoperative complications. At our center, we perform a two-step tunneling procedure that we developed based on a cadaveric study. In 125 consecutive patients operated since 2002, we did not encounter any complication related to our tunneling method. Insufficient data exist to fully evaluate the advantages and disadvantages of each tunneling technique. It is of critical importance that authors detail their tunneling modus operandi and report the presence or absence of complications. This gathered data pool may help to formulate a definitive conclusions on the safest method for subcutaneous tunneling of extension wires in deep brain stimulation.

  3. STUDY ON THE BLASTING SEISMIC DAMAGE CONTROL TECHNOLOGY FOR SMALL SPACING SOFT ROCK TUNNEL

    Directory of Open Access Journals (Sweden)

    Yang Chengzhong

    2017-07-01

    Full Text Available With a lot construction of transportation infrastructure in Chinese mountainous area, because of its unique advantages such as less land occupation, beautiful appearance and convenient route planning, small spacing tunnels are widely used. The shallow buried tunnel with small spacing, the blasting excavation will lead to tunnel surrounding rock especially in the middle rock wall damage and reduce the self-bearing capacity of surrounding rock. Through detecting and analyzing by the geological radar of the excavated red layer soft rock tunnel surrounding rock found that the middle rock wall loose circle thickness of the tunnel reaches to 1.8 m, the vault and sidewall loose circle thickness is about 1.2 m. Through selection of rational strengthening measures and blasting design scheme to improve drilling parameters and methods, as far as possible to protect the integrity and self-bearing capacity of the surrounding rock, the deformation and vibration of the tunnel would be controlled in reasonable limits and ensure the safety of tunnel construction.

  4. Carpal tunnel syndrome and the "double crush" hypothesis: a review and implications for chiropractic

    Directory of Open Access Journals (Sweden)

    Russell Brent S

    2008-04-01

    Full Text Available Abstract Upton and McComas claimed that most patients with carpal tunnel syndrome not only have compressive lesions at the wrist, but also show evidence of damage to cervical nerve roots. This "double crush" hypothesis has gained some popularity among chiropractors because it seems to provide a rationale for adjusting the cervical spine in treating carpal tunnel syndrome. Here I examine use of the concept by chiropractors, summarize findings from the literature, and critique several studies aimed at supporting or refuting the hypothesis. Although the hypothesis also has been applied to nerve compressions other than those leading to carpal tunnel syndrome, this discussion mainly examines the original application – "double crush" involving both cervical spinal nerve roots and the carpal tunnel. I consider several categories: experiments to create double crush syndrome in animals, case reports, literature reviews, and alternatives to the original hypothesis. A significant percentage of patients with carpal tunnel syndrome also have neck pain or cervical nerve root compression, but the relationship has not been definitively explained. The original hypothesis remains controversial and is probably not valid, at least for sensory disturbances, in carpal tunnel syndrome. However, even if the original hypothesis is importantly flawed, evaluation of multiple sites still may be valuable. The chiropractic profession should develop theoretical models to relate cervical dysfunction to carpal tunnel syndrome, and might incorporate some alternatives to the original hypothesis. I intend this review as a starting point for practitioners, educators, and students wishing to advance chiropractic concepts in this area.

  5. New vision of magnetic tunnelling

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, Jonathan R. [Amherst College, Amhurst, MA (United States)

    2002-01-01

    Recent experiments support the idea that crystal defects may be responsible for the quantum tunnelling of magnetic moments in molecular magnets at low temperatures. The magnetic moment of a typical bar magnet will never spontaneously reverse direction. However, thermal fluctuations can flip the moment of a magnetic particle just a few nanometres across. The particle can be cooled to nearly absolute zero to suppress this process, but the moment may still find a way to reverse via quantum tunnelling. Quantum tunnelling of magnetization has been the subject of decades of research. Until a few years ago, however, there had only been circumstantial evidence for the phenomenon. This is because most systems of small magnetic particles are hard to characterize - the particles have a variety of shapes, sizes and other properties, making it difficult to compare data with theory. Some real progress was made a few years ago through research into high-spin single-molecule magnets. With dimensions of about a nanometre, these magnets are usually composed of a magnetic core that is surrounded by organic complexes. When they crystallize into a regular lattice, the organic ions keep neighbouring magnets well separated so that they interact only weakly. Ideally all the molecules are identical because they have been built chemically, which means that they can be characterized precisely and that any data can be analysed quantitatively. The most studied of these molecules is manganese-12 acetate (Mn{sub 12}). Within each molecule, the spins of the eight Mn{sup 3+} ions (each with S=2) are antiparallel to the spins of the four Mn{sup 4+} ions (each with S=3/2), giving Mn{sub 12} a total spin of S=10. Or, to put it another way, the magnetic moment of Mn{sub 12} is 20 times larger than that of the electron. Now Eugene Chudnovsky of Lehman College in New York and Dmitry Garanin of the University of Mainz in Germany have suggested a new mechanism for producing tunnelling in Mn{sub 12

  6. Chaos regularization of quantum tunneling rates

    International Nuclear Information System (INIS)

    Pecora, Louis M.; Wu Dongho; Lee, Hoshik; Antonsen, Thomas; Lee, Ming-Jer; Ott, Edward

    2011-01-01

    Quantum tunneling rates through a barrier separating two-dimensional, symmetric, double-well potentials are shown to depend on the classical dynamics of the billiard trajectories in each well and, hence, on the shape of the wells. For shapes that lead to regular (integrable) classical dynamics the tunneling rates fluctuate greatly with eigenenergies of the states sometimes by over two orders of magnitude. Contrarily, shapes that lead to completely chaotic trajectories lead to tunneling rates whose fluctuations are greatly reduced, a phenomenon we call regularization of tunneling rates. We show that a random-plane-wave theory of tunneling accounts for the mean tunneling rates and the small fluctuation variances for the chaotic systems.

  7. Fiber coupled ultrafast scanning tunneling microscope

    DEFF Research Database (Denmark)

    Keil, Ulrich Dieter Felix; Jensen, Jacob Riis; Hvam, Jørn Märcher

    1997-01-01

    We report on a scanning tunneling microscope with a photoconductive gate in the tunneling current circuit. The tunneling tip is attached to a coplanar transmission line with an integrated photoconductive switch. The switch is illuminated through a fiber which is rigidly attached to the switch...... waveguide. The measurements show that the probe works as a transient voltage detector in contact and a capacitively coupled transient field detector in tunneling mode. We do not measure the transient voltage change in the ohmic tunneling current. In this sense, the spatial resolution for propagating...... substrate. By using a firmly attached fiber we achieve an excellent reproducibility and unconstrained positioning of the tip. We observe a transient signal with 2.9 ps pulse width in tunneling mode and 5 ps in contact mode. The instrument is applied to investigating the mode structure on a coplanar...

  8. In-mine (tunnel-to-tunnel) electrical resistance tomography in South African platinum mines

    CSIR Research Space (South Africa)

    Van Schoor, Abraham M

    2009-12-01

    Full Text Available The applicability of tunnel-to-tunnel electrical resistance tomography (ERT) for imaging disruptive geological structures ahead of mining, in an igneous platinum mining environment is assessed. The geophysical targets of interest are slump...

  9. Tunneling anisotropic magnetoresistance in Co/AIOx/Al tunnel junctions with fcc Co (111) electrodes

    NARCIS (Netherlands)

    Wang, Kai; Tran, T. Lan Ahn; Brinks, Peter; Brinks, P.; Sanderink, Johannes G.M.; Bolhuis, Thijs; van der Wiel, Wilfred Gerard; de Jong, Machiel Pieter

    2013-01-01

    Tunneling anisotropic magnetoresistance (TAMR) has been characterized in junctions comprised of face-centered cubic (fcc) Co (111) ferromagnetic electrodes grown epitaxially on sapphire substrates, amorphous AlOx tunnel barriers, and nonmagnetic Al counterelectrodes. Large TAMR ratios have been

  10. Comparison of femoral tunnel widening between outside-in and trans-tibial double-bundle ACL reconstruction.

    Science.gov (United States)

    Lee, Yong Seuk; Lee, Beom Koo; Oh, Won Seok; Cho, Yong Kyun

    2014-09-01

    The objectives of this study were to compare (1) the degree of widening by comparing the diameter at the most widened area and the site of widening by measuring the distance from the tunnel entrance to the most widened area in two femoral tunnels (anteromedial and posterolateral), and (2) the morphologic change at the tunnel entrance between outside-in and trans-tibial double-bundle anterior cruciate ligament (ACL) reconstruction. A retrospective study that included 17 trans-tibial and 19 outside-in double-bundle ACL reconstructed patients was conducted for evaluation of serial computed tomography (CT) scan (immediate post-operation and post-operative 1 year). Digital image communication in medicine (DICOM) data was extracted from the PiViewSTAR and imported into OsiriX, which was installed on a Macbook Pro laptop computer. Diameter of the most widened area and distance from the entrance to this point were measured from each of two perpendicular (sagittal and coronal) planes that were accurately realigned parallel to the tunnel direction. Change in the morphology of the tunnel entrance between immediate post-operation and 1-year post-operation was evaluated. Widening was observed in both planes of both tunnels in the two techniques. However, no statistical significances in the diameter of most widened area and distance from the tunnel entrance to the most widened point were observed between the both techniques (n.s.). Distances from the centre point to each four sections showed an increase in all four sections of all both tunnels in both techniques. However, no statistical significance was observed between the two techniques (n.s.). Widening was observed in all tunnels using both techniques and degrees, and sites of the widening did not differ between groups. Morphologic change at the tunnel entrance was not limited to the specific direction and occurred in all directions without significant difference between groups. Retrospective comparative study, Level III.

  11. PUREX Storage Tunnels dangerous waste permit application

    International Nuclear Information System (INIS)

    1991-12-01

    This report is part of a dangerous waste permit application for the storage of wastes from the Purex process at Hanford. Appendices are presented on the following: construction drawings; HSW-5638, specifications for disposal facility for failed equipment, Project CA-1513-A; HWS-8262, specification for Purex equipment disposal, Project CGC 964; storage tunnel checklist; classification of residual tank heels in Purex storage tunnels; emergency plan for Purex facility; training course descriptions; and the Purex storage tunnels engineering study

  12. MISTY ECHO tunnel dynamics experiment data report

    International Nuclear Information System (INIS)

    Phillips, J.S.; Luke, B.A.; Long, J.W.; Lee, J.G.

    1992-04-01

    Tunnel damage resulting from seismic loading is an important issue for the Yucca Mountain nuclear waste repository. The tunnel dynamics experiment was designed to obtain and document ground motions, permanent displacements, observable changes in fracture patterns, and visible damage at ground motion levels of interest to the Yucca Mountain Project. Even though the maximum free-field loading on this tunnel was 28 g, the damage observed was minor. Fielding details, data obtained, and supporting documentation are reported

  13. Theoretical approach to the scanning tunneling microscope

    International Nuclear Information System (INIS)

    Noguera, C.

    1990-01-01

    Within a one-electron approach, based on a Green's-function formalism, a nonperturbative expression for the tunneling current is obtained and used to discuss which spectroscopic information may be deduced from a scanning-tunneling-microscope experiment. It is shown up to which limits the voltage dependence of the tunneling current reproduces the local density of states at the surface, and how the reflection coefficients of the electronic waves at the surface may modify it

  14. Quantum tunneling and field electron emission theories

    CERN Document Server

    Liang, Shi-Dong

    2013-01-01

    Quantum tunneling is an essential issue in quantum physics. Especially, the rapid development of nanotechnology in recent years promises a lot of applications in condensed matter physics, surface science and nanodevices, which are growing interests in fundamental issues, computational techniques and potential applications of quantum tunneling. The book involves two relevant topics. One is quantum tunneling theory in condensed matter physics, including the basic concepts and methods, especially for recent developments in mesoscopic physics and computational formulation. The second part is the f

  15. Energy Efficiency of Tunnel Boring Machines.

    OpenAIRE

    Grishenko, Vitaly

    2014-01-01

    Herrenknecht AG is a German world-leading Tunnel Boring Machines manufacturer showing strong awareness and concern regarding environmental issues. The company supports research on the Energy Efficiency (EE) of their products, aimed at the development of intelligent design for a green Tunnel Boring Machine. The aim of this project is to produce a ’status quo’ report on EE of three types of Tunnel Boring Machines (Hardrock, EPB and Mixshield TBM). In the framework of this research 39 projects a...

  16. Climatic wind tunnel for wind engineering tasks

    Czech Academy of Sciences Publication Activity Database

    Kuznetsov, Sergeii; Pospíšil, Stanislav; Král, Radomil

    2015-01-01

    Roč. 112, 2-B (2015), s. 303-316 ISSN 1897-628X R&D Projects: GA ČR(CZ) GA14-12892S Keywords : climatic tunnel * wind tunnel * atmospheric boundary layer * flow resistance * wind tunnel contraction Subject RIV: JM - Building Engineering https://suw.biblos.pk.edu.pl/resources/i5/i6/i6/i7/i6/r56676/KuznetsovS_ClimaticWind.pdf

  17. Nuclear fission as a macroscopic quantum tunneling

    International Nuclear Information System (INIS)

    Takigawa, N.

    1995-01-01

    We discuss nuclear fission from the point of view of a macroscopic quantum tunneling, one of whose major interests is to study the effects of environments on the tunneling rate of a macroscopic variable. We show that a vibrational excitation of the fissioning nucleus significantly enhances the fission rate. We show this effect by two different methods. The one is to treat the vibrational excitation as an environmental degree of freedom, the other treats the fission as a two dimensional quantum tunneling. (author)

  18. Big data and software defined networks

    CERN Document Server

    Taheri, Javid

    2018-01-01

    Big Data Analytics and Software Defined Networking (SDN) are helping to drive the management of data usage of the extraordinary increase of computer processing power provided by Cloud Data Centres (CDCs). This new book investigates areas where Big-Data and SDN can help each other in delivering more efficient services.

  19. Femtosecond tunneling response of surface plasmon polaritons

    DEFF Research Database (Denmark)

    Keil, Ulrich Dieter Felix; Ha, Taekjip; Jensen, Jacob Riis

    1998-01-01

    We obtain femtosecond (200 fs) time resolution using a scanning tunneling microscope on surface plasmon polaritons (SPPs) generated by two 100 fs laser beams in total internal reflection geometry. The tunneling gap dependence of the signal clearly indicates the tunneling origin of the signal...... and suggests that nanometer spatial resolution can be obtained together with femtosecond temporal resolution. This fast response, in contrast to the picosecond decay time of SPPs revealed by differential reflectivity measurements, can be attributed to a coherent superposition of SPPs rectified at the tunneling...

  20. PUREX Storage Tunnels dangerous waste permit application

    International Nuclear Information System (INIS)

    1991-12-01

    The PUREX Storage Tunnels are a mixed waste storage unit consisting of two underground railroad tunnels: Tunnel Number 1 designated 218-E-14 and Tunnel Number 2 designated 218-E-15. The two tunnels are connected by rail to the PUREX Plant and combine to provide storage space for 48 railroad cars (railcars). The PUREX Storage Tunnels provide a long-term storage location for equipment removed from the PUREX Plant. Transfers into the PUREX Storage Tunnels are made on an as-needed basis. Radioactively contaminated equipment is loaded on railcars and remotely transferred by rail into the PUREX Storage Tunnels. Railcars act as both a transport means and a storage platform for equipment placed into the tunnels. This report consists of part A and part B. Part A reports on amounts and locations of the mixed water. Part B permit application consists of the following: Facility Description and General Provisions; Waste Characteristics; Process Information; Groundwater Monitoring; Procedures to Prevent Hazards; Contingency Plan; Personnel Training; Exposure Information Report

  1. Relativistic tunneling through two successive barriers

    International Nuclear Information System (INIS)

    Lunardi, Jose T.; Manzoni, Luiz A.

    2007-01-01

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

  2. Tunnelling in Dante's Inferno

    Energy Technology Data Exchange (ETDEWEB)

    Furuuchi, Kazuyuki [Manipal Centre for Natural Sciences, Manipal University, Dr.T.M.A. Pai Planetarium Building, Madhav Nagar, Manipal, Karnataka 576104 (India); Sperling, Marcus, E-mail: kazuyuki.furuuchi@manipal.edu, E-mail: marcus.sperling@univie.ac.at [Fakultät für Physik, Universität Wien, Boltzmanngasse 5, A-1090 Wien (Austria)

    2017-05-01

    We study quantum tunnelling in Dante's Inferno model of large field inflation. Such a tunnelling process, which will terminate inflation, becomes problematic if the tunnelling rate is rapid compared to the Hubble time scale at the time of inflation. Consequently, we constrain the parameter space of Dante's Inferno model by demanding a suppressed tunnelling rate during inflation. The constraints are derived and explicit numerical bounds are provided for representative examples. Our considerations are at the level of an effective field theory; hence, the presented constraints have to hold regardless of any UV completion.

  3. Tunneling with dissipation in open quantum systems

    International Nuclear Information System (INIS)

    Adamyan, G.G.; Antonenko, N.V.; Scheid, W.

    1997-01-01

    Based on the general form of the master equation for open quantum systems the tunneling is considered. Using the path integral technique a simple closed form expression for the tunneling rate through a parabolic barrier is obtained. The tunneling in the open quantum systems strongly depends on the coupling with environment. We found the cases when the dissipation prohibits tunneling through the barrier but decreases the crossing of the barrier for the energies above the barrier. As a particular application, the case of decay from the metastable state is considered

  4. Fire safety assessment of tunnel structures

    DEFF Research Database (Denmark)

    Gkoumas, Konstantinos; Giuliani, Luisa; Petrini, Francesco

    2011-01-01

    .g. structural and non structural, organizational, human behavior). This is even more truth for the fire safety design of such structures. Fire safety in tunnels is challenging because of the particular environment, bearing in mind also that a fire can occur in different phases of the tunnel’s lifecycle. Plans...... for upgrading fire safety provisions and tunnel management are also important for existing tunnels. In this study, following a brief introduction of issues regarding the above mentioned aspects, the structural performance of a steel rib for a tunnel infrastructure subject to fire is assessed by means...

  5. Resonant tunneling of electrons in quantum wires

    International Nuclear Information System (INIS)

    Krive, I.V.; Shekhter, R.I.; Jonson, M.; Krive, I.V.

    2010-01-01

    We considered resonant electron tunneling in various nanostructures including single wall carbon nanotubes, molecular transistors and quantum wires formed in two-dimensional electron gas. The review starts with a textbook description of resonant tunneling of noninteracting electrons through a double-barrier structure. The effects of electron-electron interaction in sequential and resonant electron tunneling are studied by using Luttinger liquid model of electron transport in quantum wires. The experimental aspects of the problem (fabrication of quantum wires and transport measurements) are also considered. The influence of vibrational and electromechanical effects on resonant electron tunneling in molecular transistors is discussed.

  6. Tunnelling in Dante's Inferno

    International Nuclear Information System (INIS)

    Furuuchi, Kazuyuki; Sperling, Marcus

    2017-01-01

    We study quantum tunnelling in Dante's Inferno model of large field inflation. Such a tunnelling process, which will terminate inflation, becomes problematic if the tunnelling rate is rapid compared to the Hubble time scale at the time of inflation. Consequently, we constrain the parameter space of Dante's Inferno model by demanding a suppressed tunnelling rate during inflation. The constraints are derived and explicit numerical bounds are provided for representative examples. Our considerations are at the level of an effective field theory; hence, the presented constraints have to hold regardless of any UV completion.

  7. Electronic tunneling currents at optical frequencies

    Science.gov (United States)

    Faris, S. M.; Fan, B.; Gustafson, T. K.

    1975-01-01

    Rectification characteristics of nonsuperconducting metal-barrier-metal junctions as deduced from electronic tunneling theory have been observed experimentally for optical frequency irradiation of the junction.

  8. Lowest order in inelastic tunneling approximation : efficient scheme for simulation of inelastic electron tunneling data

    NARCIS (Netherlands)

    Rossen, E.T.R.; Flipse, C.F.J.; Cerda, J.I.

    2013-01-01

    We have developed an efficient and accurate formalism which allows the simulation at the ab initio level of inelastic electron tunneling spectroscopy data under a scanning tunneling microscope setup. It exploits fully the tunneling regime by carrying out the structural optimization and vibrational

  9. Probing spin-polarized tunneling at high bias and temperature with a magnetic tunnel transistor

    NARCIS (Netherlands)

    Park, B.G.; Banerjee, T.; Min, B.C.; Sanderink, Johannes G.M.; Lodder, J.C.; Jansen, R.

    2005-01-01

    The magnetic tunnel transistor (MTT) is a three terminal hybrid device that consists of a tunnel emitter, a ferromagnetic (FM) base, and a semiconductor collector. In the MTT with a FM emitter and a single FM base, spin-polarized hot electrons are injected into the base by tunneling. After

  10. Resonant tunneling via spin-polarized barrier states in a magnetic tunnel junction

    NARCIS (Netherlands)

    Jansen, R.; Lodder, J.C.

    2000-01-01

    Resonant tunneling through states in the barrier of a magnetic tunnel junction has been analyzed theoretically for the case of a spin-polarized density of barrier states. It is shown that for highly spin-polarized barrier states, the magnetoresistance due to resonant tunneling is enhanced compared

  11. A Study of Vertical Transport through Graphene toward Control of Quantum Tunneling.

    Science.gov (United States)

    Zhu, Xiaodan; Lei, Sidong; Tsai, Shin-Hung; Zhang, Xiang; Liu, Jun; Yin, Gen; Tang, Min; Torres, Carlos M; Navabi, Aryan; Jin, Zehua; Tsai, Shiao-Po; Qasem, Hussam; Wang, Yong; Vajtai, Robert; Lake, Roger K; Ajayan, Pulickel M; Wang, Kang L

    2018-02-14

    Vertical integration of van der Waals (vdW) materials with atomic precision is an intriguing possibility brought forward by these two-dimensional (2D) materials. Essential to the design and analysis of these structures is a fundamental understanding of the vertical transport of charge carriers into and across vdW materials, yet little has been done in this area. In this report, we explore the important roles of single layer graphene in the vertical tunneling process as a tunneling barrier. Although a semimetal in the lateral lattice plane, graphene together with the vdW gap act as a tunneling barrier that is nearly transparent to the vertically tunneling electrons due to its atomic thickness and the transverse momenta mismatch between the injected electrons and the graphene band structure. This is accentuated using electron tunneling spectroscopy (ETS) showing a lack of features corresponding to the Dirac cone band structure. Meanwhile, the graphene acts as a lateral conductor through which the potential and charge distribution across the tunneling barrier can be tuned. These unique properties make graphene an excellent 2D atomic grid, transparent to charge carriers, and yet can control the carrier flux via the electrical potential. A new model on the quantum capacitance's effect on vertical tunneling is developed to further elucidate the role of graphene in modulating the tunneling process. This work may serve as a general guideline for the design and analysis of vdW vertical tunneling devices and heterostructures, as well as the study of electron/spin injection through and into vdW materials.

  12. Effect of surface loading on the hydro-mechanical response of a tunnel in saturated ground

    Directory of Open Access Journals (Sweden)

    Simon Heru Prassetyo

    2016-09-01

    Full Text Available The design of underground spaces in urban areas must account not only for the current overburden load but also for future surface loads, such as from construction of high-rise buildings above underground structures. In saturated ground, the surface load will generate an additional mechanical response through stress changes and ground displacement, as well as a hydraulic response through pore pressure changes. These hydro-mechanical (H-M changes can severely influence tunnel stability. This paper examines the effect of surface loading on the H-M response of a typical horseshoe-shaped tunnel in saturated ground. Two tunnel models were created in the computer code Fast Lagrangian Analysis of Continua (FLAC. One model represented weak and low permeability ground (stiff clay, and the other represented strong and high permeability ground (weathered granite. Each of the models was run under two liner permeabilities: permeable and impermeable. Two main cases were compared. In Case 1, the surface load was applied 10 years after tunnel construction. In Case 2, the surface load was applied after the steady state pore pressure condition was achieved. The simulation results show that tunnels with impermeable liners experienced the most severe influence from the surface loading, with high pore pressures, large inward displacement around the tunnels, and high bending moments in the liner. In addition, the severity of the response increased toward steady state. This induced H-M response was worse for tunnels in clay than for those in granite. Furthermore, the long-term liner stabilities in Case 1 and Case 2 were similar, indicating that the influence of the length of time between when the tunnel was completed and when the surface load was applied was negligible. These findings suggest that under surface loading, in addition to the ground strength, tunnel stability in saturated ground is largely influenced by liner permeability and the long-term H-M response of

  13. Bone tunnel change develops within two weeks of double-bundle anterior cruciate ligament reconstruction using hamstring autograft: A comparison of different postoperative immobilization periods using computed tomography.

    Science.gov (United States)

    Shimizu, Ryo; Adachi, Nobuo; Ishifuro, Minoru; Nakamae, Atsuo; Ishikawa, Masakazu; Deie, Masataka; Ochi, Mitsuo

    2017-10-01

    The purpose of this study was to evaluate bone tunnel changes following anterior cruciate ligament (ACL) reconstruction during the early postoperative period using computed tomography (CT), and to understand the impact of postoperative immobilization on these changes. Twenty patients who underwent double-bundle ACL reconstruction using hamstring tendon autografts were included. We subcategorized patients into two groups: patients who underwent isolated ACL reconstruction and had three days of knee immobilization (Group A, n=10); and patients with concomitant meniscus injuries who underwent ACL reconstruction and meniscus repair simultaneously (Group B, n=10) had their knees immobilized for two weeks after surgery. Bone tunnel enlargement was evaluated using CT imaging at one to three days, two weeks, one month, three months and six months after surgery. The cross-sectional area of the femoral and tibial tunnels was measured, and enlargement rate was calculated. The tunnel center location at two weeks after surgery was also evaluated. The mean cross-sectional area adjacent to the joint space of the femoral and tibial tunnels significantly increased immediately after surgery, especially in the first month (P0.01). There was no significant difference in tunnel enlargement rate between group A and B. Tunnel center location changed even in the first two weeks. Bone tunnel enlargement following double-bundle ACL reconstruction occurred at an earlier time point after surgery than anticipated. Postoperative immobilization could not prevent bone tunnel enlargement, but might prevent tunnel migration. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Reactive transport predictions for an Olkiluoto. Final repository tunnel unit

    International Nuclear Information System (INIS)

    Luukkonen, A.; Nordman, H.

    2007-09-01

    The presented hydrogeochemical reactive transport calculations concentrate to a defined unit piece (unit cell) of the planned Olkiluoto repository that is under design for spent nuclear fuel. The material properties assigned to the tunnel unit are based on literature as far as possible. Calculations make up geochemical future scenarios on the repository evolution. Most recent predictions on the potential future climate at Olkiluoto are utilised together with estimates how future hydraulic conditions affect the repository. Two climate scenarios are considered in detail. The Weichselian-R scenario is based on the repetition of the last glacial cycle, while the Emissions-M scenario attempts to predict the future groundwater conditions at Olkiluoto in the situation where the atmospheric greenhouse gasses delay the next glacial cycle at least for 100,000 years. The groundwater compositions, considered active at the repository depth in future, are judged in this study. Several geochemical processes are considered active at the repository depth. Calculations concentrate on the changes occurring with time within the tunnel unit. All simulations are done in geochemically reducing conditions. It turns out that sulphur cycling in these conditions is in central role considering the safety assessment studies of Olkiluoto repository. Furthermore, groundwater salinity and cation occupancy within the exchange sites of montmorillonite contributes to sealing properties of the engineered barrier system. Calculations attempt to estimate effects of possible future scenarios for the Olkiluoto repository. The results indicate that the buffer capacities assigned to the tunnel unit are large enough, at least to next 100,000 years, to maintain dissolved sulphide contents low in the groundwater infiltrating through the tunnel engineered barrier system. Geochemical reactions raise the bicarbonate levels within the groundwater. This is a useful buffer if low pH conditions emerge in the

  15. New Technology and Experimental Study on Snow-Melting Heated Pavement System in Tunnel Portal

    Directory of Open Access Journals (Sweden)

    Jinxing Lai

    2015-01-01

    Full Text Available In recent years, with the rapid growth of economy and sharp rise of motor vehicles in China, the pavement skid resistance in tunnel portals has become increasingly important in cold region. However, the deicing salt, snow removal with machine, and other antiskid measures adopted by highway maintenance division have many limitations. To improve the treatment effect, we proposed a new snow-melting approach employing electric heat tracing, in which heating cables are installed in the structural layer of road. Through the field experiment, laboratory experiment, and numerical investigation, structure type, heating power, and preheating time of the flexible pavement heating system in tunnel portal were systematically analyzed, and advantages of electric heat tracing technology in improving the pavement skid resistance in tunnel portal were also presented. Therefore, such new technology, which offers new snow-melting methods for tunnel portal, bridge, mountainous area, and large longitudinal slope in cold region, has promising prospect for extensive application.

  16. Sidewall GaAs tunnel junctions fabricated using molecular layer epitaxy

    Directory of Open Access Journals (Sweden)

    Takeo Ohno and Yutaka Oyama

    2012-01-01

    Full Text Available In this article we review the fundamental properties and applications of sidewall GaAs tunnel junctions. Heavily impurity-doped GaAs epitaxial layers were prepared using molecular layer epitaxy (MLE, in which intermittent injections of precursors in ultrahigh vacuum were applied, and sidewall tunnel junctions were fabricated using a combination of device mesa wet etching of the GaAs MLE layer and low-temperature area-selective regrowth. The fabricated tunnel junctions on the GaAs sidewall with normal mesa orientation showed a record peak current density of 35 000 A cm-2. They can potentially be used as terahertz devices such as a tunnel injection transit time effect diode or an ideal static induction transistor.

  17. The role of sediment supply in esker formation and ice tunnel evolution

    Science.gov (United States)

    Burke, Matthew J.; Brennand, Tracy A.; Sjogren, Darren B.

    2015-05-01

    Meltwater is an important part of the glacier system as it can directly influence ice sheet dynamics. Although it is important that ice sheet models incorporate accurate information about subglacial meltwater processes, the relative inaccessibility of contemporary ice sheet beds makes direct investigation challenging. Former ice sheet beds contain a wealth of meltwater landforms such as eskers that, if accurately interpreted, can provide detailed insight into the hydrology of former ice sheets. Eskers are the casts of ice-walled channels and are a common landform within the footprint of the last Laurentide and Cordilleran Ice Sheets. In south-western Alberta, esker distribution suggests that both water and sediment supply may have been important controls; the longest esker ridge segments are located within meltwater valleys partially filled by glaciofluvial sediments, whereas the shortest esker ridge segments are located in areas dominated by clast-poor till. Through detailed esker ridge planform and crest-type mapping, and near surface geophysics we reveal morpho-sedimentary relationships that suggest esker sedimentation was dynamic, but that esker distribution and architecture were primarily governed by sediment supply. Through comparison of these data with data from eskers elsewhere, we suggest three formative scenarios: 1) where sediment supply and flow powers were high, coarse sediment loads result in rapid deposition, and rates of thermo-mechanical ice tunnel growth is exceeded by the rate of ice tunnel closure due to sediment infilling. High sedimentation rates reduce ice tunnel cross-sectional area, cause an increase in meltwater flow velocity and force ice tunnel growth. Thus, ice tunnel growth is fastest where sedimentation rate is highest; this positive feedback results in a non-uniform ice tunnel geometry, and favours macroform development and non-uniform ridge geometry. 2) Where sediment supply is limited, but flow power high, the rate of sedimentation

  18. R.f.-induced steps in mutually coupled, two-dimensional distributed Josephson tunnel junctions

    International Nuclear Information System (INIS)

    Klein, U.; Dammschneider, P.

    1991-01-01

    This paper reports on the amplitudes of the current steps in the I-V characteristics of mutually coupled two-dimensional distributed Josephson tunnel junctions driven by microwaves. For this purpose we use a numerical computation algorithm based on a planar resonator model for the individual Josephson tunnel junctions to calculate the d.c. current density distribution. In addition to the fundamental microwave frequency, harmonic contents of the tunneling current are also considered. The lateral dimensions of the individual junctions are small compared to the microwave wavelength and the Josephson penetration depth, giving an almost constant current density distribution. Therefore, the coupled junctions can give much greater step amplitudes than a single junction with an equal tunneling area, because of their nonuniform current density distribution

  19. Effects of polymer corrosion inhibitor on widening etch tunnels of aluminum foil for capacitor

    International Nuclear Information System (INIS)

    Ban, Chaolei; He, Yedong; Shao, Xin; Wang, Zhishen

    2014-01-01

    Highlights: •With PSSA, the exterior surface dissolution of etched Al foil is suppressed. •With PSSA, the interior surface dissolution of etched Al foil is facilitated. •With PSSA, the tunnels are widened along the entire length. •With PSSA, the area and capacitance of etched Al foil are significantly improved. -- Abstract: We investigated the effects of polymeric corrosion inhibitor polystyrene sulfonic acid (PSSA) additive to 3% HNO 3 solution on widening tunnels of pre-etched aluminum foil by electrochemical DC etching for aluminum electrolytic capacitors, using scanning electron microscopy and polarization curves. With trace PSSA, the dissolution of exterior surface of etch tunnels of Al foil is suppressed and the dissolution of interior surface of etch tunnels of Al foil is facilitated, respectively. The tunnels transform from circular cone to circular column in shape and pits-merging on the surface is weakened, leading to significant increase in the surface area and specific capacitance of the Al foil. The amounts of reduced thickness and weight of Al foil during the widening process of etch tunnels can be decreased if PSSA is employed

  20. Giant electrode effect on tunnelling electroresistance in ferroelectric tunnel junctions.

    Science.gov (United States)

    Soni, Rohit; Petraru, Adrian; Meuffels, Paul; Vavra, Ondrej; Ziegler, Martin; Kim, Seong Keun; Jeong, Doo Seok; Pertsev, Nikolay A; Kohlstedt, Hermann

    2014-11-17

    Among recently discovered ferroelectricity-related phenomena, the tunnelling electroresistance (TER) effect in ferroelectric tunnel junctions (FTJs) has been attracting rapidly increasing attention owing to the emerging possibilities of non-volatile memory, logic and neuromorphic computing applications of these quantum nanostructures. Despite recent advances in experimental and theoretical studies of FTJs, many questions concerning their electrical behaviour still remain open. In particular, the role of ferroelectric/electrode interfaces and the separation of the ferroelectric-driven TER effect from electrochemical ('redox'-based) resistance-switching effects have to be clarified. Here we report the results of a comprehensive study of epitaxial junctions comprising BaTiO(3) barrier, La(0.7)Sr(0.3)MnO(3) bottom electrode and Au or Cu top electrodes. Our results demonstrate a giant electrode effect on the TER of these asymmetric FTJs. The revealed phenomena are attributed to the microscopic interfacial effect of ferroelectric origin, which is supported by the observation of redox-based resistance switching at much higher voltages.