Science.gov

Sample records for defined tunneling area

  1. High Surface Area Tunnels in Hexagonal WO₃.

    PubMed

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

    2015-07-01

    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.

  2. Area and shape changes of the carpal tunnel in response to tunnel pressure.

    PubMed

    Li, Zong-Ming; Masters, Tamara L; Mondello, Tracy A

    2011-12-01

    Carpal tunnel mechanics is relevant to our understanding of median nerve compression in the tunnel. The compliant characteristics of the tunnel strongly influence its mechanical environment. We investigated the distensibility of the carpal tunnel in response to tunnel pressure. A custom balloon device was designed to apply controlled pressure. Tunnel cross sections were obtained using magnetic resonance imaging to derive the relationship between carpal tunnel pressure and morphological parameters at the hook of hamate. The results showed that the cross-sectional area (CSA) at the level of the hook of hamate increased, on average, by 9.2% and 14.8% at 100 and 200 mmHg, respectively. The increased CSA was attained by a shape change of the cross section, displaying increased circularity. The increase in CSA was mainly attributable to the increase of area in the carpal arch region formed by the transverse carpal ligament. The narrowing of the carpal arch width was associated with an increase in the carpal arch. We concluded that the carpal tunnel is compliant to accommodate physiological variations of the carpal tunnel pressure, and that the increase in tunnel CSA is achieved by increasing the circularity of the cross section.

  3. Methods on defining the urban fringe area of Beijing

    NASA Astrophysics Data System (ADS)

    Wang, Xiulan; Li, Xuerui; Feng, Zhongke; Fang, Yuan

    2009-09-01

    Urban fringe lies in the transitional region between urban area and rural area. Defining the urban fringe area and researching the changing situation will be beneficial to the urban planning and the readjustment of land use structure. Taking Land-Sat TM images as basic information, using the theories of Shannon entropy and land use degree comprehensive index, methods on how to define the urban fringe area of Beijing are discussed. Further, the urban fringe area of Beijing is defined by using these two methods. It shows that the urban fringe area in Beijing includes a part of the urban district and also a small part of rural district. Distributing ring, it extends around irregularly, especially northwest and southeast.

  4. Methods on defining the urban fringe area of Beijing

    NASA Astrophysics Data System (ADS)

    Wang, Xiulan; Li, Xuerui; Feng, Zhongke; Fang, Yuan

    2010-11-01

    Urban fringe lies in the transitional region between urban area and rural area. Defining the urban fringe area and researching the changing situation will be beneficial to the urban planning and the readjustment of land use structure. Taking Land-Sat TM images as basic information, using the theories of Shannon entropy and land use degree comprehensive index, methods on how to define the urban fringe area of Beijing are discussed. Further, the urban fringe area of Beijing is defined by using these two methods. It shows that the urban fringe area in Beijing includes a part of the urban district and also a small part of rural district. Distributing ring, it extends around irregularly, especially northwest and southeast.

  5. Geology of the Rainier Mesa-Aqueduct Mesa tunnel areas: U12n tunnel

    SciTech Connect

    Hoover, D.L.; Magner, J.E.

    1990-01-01

    The U12n tunnel area is located beneath Rainier Mesa on the Nevada Test Site, Nye County, Nevada. Stratigraphic units in the U12n area include Precambrian and Cambrian quartzite, Ordovician to Devonian dolomite and limestone, Cretaceous quartz monzonite, 25 Miocene and Pliocene volcanic rock units, and Quaternary colluvium and alluvium. Volcanic rocks in drill holes are classified into two chemical groups, four depositional processes, and four alteration types. Alteration of the volcanic rocks to predominantly zeolites, clay minerals, or silica is related to both stratigraphy and structure. Pre-volcanic structures are the CP thrust fault, a right-lateral fault zone that can be projected into the U12n area, and the Gold Meadows stock; Tertiary structures are depositional folds and predominantly normal faults. The right-lateral fault zone may have provided pre-existing planes of weakness during Tertiary deformation that resulted in west-northwest to northwest normal faults in the U12n area in contrast to north-south to north-northeast faults north and south of the U12n area. Normal faults at tunnel level have displacements that range from less than 3 to 125 ft or more. The Tertiary volcanic rocks were deposited on a pre-Tertiary, steep-sided drainage system and formed depositional folds. The Rainier Mesa depositional syncline is the major structures in the U12n area in addition to the normal faults. Drill-hole data indicate that the axis of syncline in the volcanic rocks parallels the contact between quartzite in the upper plate and dolomite and limestone in the lower plate of the CP thrust fault. 29 refs., 6 figs., 10 tabs.

  6. Contact-area metrology of magnetic tunneling junction structures

    NASA Astrophysics Data System (ADS)

    Zhong, Tom; Liu, Daniel; Moran, Amit; Levkovitch, Michael; Har-Zvi, Michael; Burkhardt, Bob

    2006-03-01

    Magneto-resistive Random Access Memory (MRAM), considered the leading candidate for the next generation of universal memory, has moved from research to pilot production. Commercialization of the MRAM devices in mobile computing, cell phones, portable recording and other playback devices, home computing, consumer electronics, enterprise computing and telecommunications, promise to bring in annual revenues exceeding $50 billion during the coming years. CD-SEM correlation of contact physical Critical Dimension to Magnetic Tunneling Junction (MTJ) resistance is critical for MRAM device performance. This paper focuses on a new two-dimensional metric that more accurately characterizes MTJ resistance by calculating total contact area of unique and complex structures. We consider the advantages of the Contact Area metric for measurement of complicated shapes. We illustrate that introduction of the new metric allows for improvement in process control for critical contacts.

  7. Carpal Tunnel Cross-Sectional Area Affected by Soft Tissues Abutting the Carpal Bones.

    PubMed

    Gabra, Joseph N; Li, Zong-Ming

    2013-02-01

    The carpal tunnel accommodates free movement of its contents, and the tunnel's cross-sectional area is a useful morphological parameter for the evaluation of the space available for the carpal tunnel contents and of potential nerve compression in the tunnel. The osseous boundary of the carpal bones as the dorsal border of the carpal tunnel is commonly used to determine the tunnel area, but this boundary contains soft tissues such as numerous intercarpal ligaments and the flexor carpi radialis tendon. The aims of this study were to quantify the thickness of the soft tissues abutting the carpal bones and to investigate how this soft tissue influences the calculation of the carpal tunnel area. Magnetic resonance images were analyzed for eight cadaveric specimens. A medical balloon with a physiological pressure was inserted into an evacuated tunnel to identify the carpal tunnel boundary. The balloon-based (i.e. true carpal tunnel) and osseous-based carpal tunnel boundaries were extracted and divided into regions corresponding to the hamate, capitate, trapezoid, trapezium, and transverse carpal ligament (TCL). From the two boundaries, the overall and regional soft tissue thicknesses and areas were calculated. The soft tissue thickness was significantly greater for the trapezoid (3.1±1.2mm) and trapezium (3.4±1.0mm) regions than for the hamate (0.7±0.3mm) and capitate (1.2±0.5mm) regions. The carpal tunnel area using the osseous boundary (243.0±40.4mm(2)) was significantly larger than the balloon-based area (183.9±29.7mm(2)) with a ratio of 1.32. In other words, the carpal tunnel area can be estimated as 76% (= 1/1.32) of the osseous-based area. The abundance of soft tissue in the trapezoid and trapezium regions can be attributed mainly to the capitate-trapezium ligament and the flexor carpi radialis tendon. Inclusion of such soft tissue leads to overestimations of the carpal tunnel area. Correct quantification of the carpal tunnel area aids in examining carpal

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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. Facility Closure Report for T-Tunnel (U12t), Area 12, Nevada Test Site, Nevada

    SciTech Connect

    NSTec Environmental Restoration

    2008-08-01

    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.

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

    SciTech Connect

    Geuther, W.J., Westinghouse Hanford

    1996-08-30

    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.

  12. Sub micron area Nb/AlO(x)/Nb tunnel junctions for submillimeter mixer applications

    NASA Technical Reports Server (NTRS)

    Leduc, Henry G.; Bumble, B.; Cypher, S. R.; Judas, A. J.; Stern, J. A.

    1992-01-01

    In this paper, we report on a fabrication process developed for submicron area tunnel junctions. We have fabricated Nb/AlO(x)/Nb tunnel junctions with areas down to 0.1 sq micron using these techniques. The devices have shown excellent performance in receiver systems up to 500 GHz and are currently in use in radio astronomy observatories at 115, 230, and 500 GHz.

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

    NASA Astrophysics Data System (ADS)

    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

  14. The new hospice compliance plan: defining and addressing risk areas.

    PubMed

    Jones, D H; Woods, K

    2000-05-01

    The Department of Health and Human Services' (HHS) Office of the Inspector General (OIG), has advised hospices and other health care providers to formulate effective controls to ensure compliance with federal and state statutes, rules, and regulations, and private-payor health care program requirements. The recently released guidelines provide a blueprint for developing such programs. This is the first of four installments that focus specifically on the 28 risk areas identified in the guidance and offer strategies for incorporating them in a hospice compliance program. The authors have organized the 28 risk areas under 9 topic domains to simplify the task of tackling the guidance. This article covers the first two areas: Admission/Certification/Recertification and Billing.

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

    SciTech Connect

    Tollin, S. . Dept. of Geosciences)

    1993-03-01

    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

    SciTech Connect

    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. Does the ratio of the carpal tunnel inlet and outlet cross-sectional areas in the median nerve reflect carpal tunnel syndrome severity?

    PubMed

    Zhang, Li; Rehemutula, Aierken; Peng, Feng; Yu, Cong; Wang, Tian-Bin; Chen, Lin

    2015-07-01

    Although ultrasound measurements have been used in previous studies on carpal tunnel syndrome to visualize injury to the median nerve, whether such ultrasound data can indicate the severity of carpal tunnel syndrome remains controversial. The cross-sectional areas of the median nerve at the tunnel inlet and outlet can show swelling and compression of the nerve at the carpal. We hypothesized that the ratio of the cross-sectional areas of the median nerve at the carpal tunnel inlet to outlet accurately reflects the severity of carpal tunnel syndrome. To test this, high-resolution ultrasound with a linear array transducer at 5-17 MHz was used to assess 77 patients with carpal tunnel syndrome. The results showed that the cut-off point for the inlet-to-outlet ratio was 1.14. Significant differences in the inlet-to-outlet ratio were found among patients with mild, moderate, and severe carpal tunnel syndrome. The cut-off point in the ratio of cross-sectional areas of the median nerve was 1.29 between mild and more severe (moderate and severe) carpal tunnel syndrome patients with 64.7% sensitivity and 72.7% specificity. The cut-off point in the ratio of cross-sectional areas of the median nerve was 1.52 between the moderate and severe carpal tunnel syndrome patients with 80.0% sensitivity and 64.7% specificity. These results suggest that the inlet-to-outlet ratio reflected the severity of carpal tunnel syndrome.

  18. A micrometer-size movable light emitting area in a resonant tunneling light emitting diode

    SciTech Connect

    Pettinari, G.; Balakrishnan, N.; Makarovsky, O.; Campion, R. P.; Patanè, A.; Polimeni, A.; Capizzi, M.

    2013-12-09

    We report on the fabrication of a micrometer-size movable light emitting area in a GaAs/AlAs quantum well resonant tunneling p-i-n diode. The spatial position of the micrometer-size light emitting area shifts linearly with increasing applied bias, up to 30 μm for a bias increment of 0.2 V. Also, the simultaneous resonant tunneling injection of both electrons and holes into the quantum well states is achieved at specific positions of the diode, thus resulting in a tenfold increase of the electroluminescence intensity.

  19. Design and validation of a wind tunnel system for odour sampling on liquid area sources.

    PubMed

    Capelli, L; Sironi, S; Del Rosso, R; Céntola, P

    2009-01-01

    The aim of this study is to describe the methods adopted for the design and the experimental validation of a wind tunnel, a sampling system suitable for the collection of gaseous samples on passive area sources, which allows to simulate wind action on the surface to be monitored. The first step of the work was the study of the air velocity profiles. The second step of the work consisted in the validation of the sampling system. For this purpose, the odour concentration of some air samples collected by means of the wind tunnel was measured by dynamic olfactometry. The results of the air velocity measurements show that the wind tunnel design features enabled the achievement of a uniform and homogeneous air flow through the hood. Moreover, the laboratory tests showed a very good correspondence between the odour concentration values measured at the wind tunnel outlet and the odour concentration values predicted by the application of a specific volatilization model, based on the Prandtl boundary layer theory. The agreement between experimental and theoretical trends demonstrate that the studied wind tunnel represents a suitable sampling system for the simulation of specific odour emission rates from liquid area sources without outward flow.

  20. Comparative study of European tunnel emergency-stop-area-wall protection measures.

    PubMed

    Kunc, Robert; Omerović, Senad; Ambrož, Miha; Prebil, Ivan

    2014-02-01

    Due to the increasing number of traffic accidents involving the collisions of vehicles with the emergency-stop-area head walls in tunnels, a comparative numerical analysis in accordance with the EN 1317 standard has been performed in order to assess the quality of the available protective safety barriers. Based on the simulation results, the values of the relevant injury criteria - the acceleration severity index (ASI), the theoretical head impact velocity (THIV) and the post-impact head deceleration (PHD) - were computed for several collision scenarios involving two different passenger vehicles colliding with two different safety barriers in various ways. The results show that due to the geometrical restrictions in the tunnel's emergency stop area none of the barriers can provide total protection for the occupants of the vehicle in the event of a collision. The installation of a steel-sheet-tube crash cushion was, however, found to provide the best possible protection within the given limitations. The results of the analysis were the basis for selecting a safety-barrier design for existing tunnel installations and for the proposed changes in regulations governing the geometry of the tunnel's emergency stop area.

  1. Tunnelling in Urbanised Areas - Geotechnical Case Studies at Different Project Stages

    NASA Astrophysics Data System (ADS)

    Eder, Stefan; Poscher, Gerhard; Kohl, Bernhard

    Tunnelling in urbanised areas is always a challenge for the client and the contractor as well as for the designers, the engineers, and the geologists. The high demand for space and the disturbance of existing infrastructures by construction measures increasingly forces future infrastructure projects to be carried out underground. At the same time, interferences with human, natural or water resources shall be reduced and noise, dust, as well as site traffic shall be minimised. Quite frequently, politics also come into play. All these factors may lead to pre-determined routes, with ground conditions which may not always be very favourable. This article presents examples of different projects at different stages and emphasizes the importance of engineering geology in the route selection process. The most promising options are routes located in ground, which is not sensitive to settlement and/or water ingress. A longer route in favourable ground conditions is to be given preference over a shorter route in adverse ground conditions. In case of no alternative, the risk of surface settlements and exploding construction costs have to be taken into account. The first project presented is the railway line in the Inn valley / Tyrol, comprising four sections in urbanised areas, which - due to environmental and political reasons - have to cross infrastructure facilities and traffic lines, often in unfavourable ground conditions. There is a variety of construction methods in the tender design to be applied in urbanised tunnelling ranging from NATM tunnels with local groundwater draw-down and jet grouting enclosure against water pressure, to TBM-driven tunnels with hydro-shield. The second project is a planned by-pass for the city of Linz, which is at the environmental impact assessment stage. The alignment is dominated by geological considerations, avoiding unfavourable ground conditions to the greatest possible extent.

  2. Changes in Clinical Symptoms, Functions, and the Median Nerve Cross-Sectional Area at the Carpal Tunnel Inlet after Open Carpal Tunnel Release

    PubMed Central

    Koh, Young-Do; Kim, Jong Oh; Choi, Shin Woo

    2016-01-01

    Background The aim of this study was to investigate the relationship between clinical symptoms and cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet before and after open carpal tunnel release (CTR). Methods Thirty-two patients (53 hands) that underwent open CTR for idiopathic carpal tunnel syndrome were prospectively enrolled. Median nerve CSA at the carpal tunnel inlet was measured preoperatively and at 2 and 12 weeks after CTR by high resolution ultrasonography. The Boston carpal tunnel questionnaire (BCTQ) was also completed at these times. Results BCTQ symptom (BCTQ-S) score was significantly improved at 2 weeks postoperatively, but BCTQ function (BCTQ-F) score and CSA were significantly improved at 12 weeks postoperatively. Preoperative CSA was significantly correlated with preoperative BCTQ-S and BCTQ-F scores but was not significantly correlated with postoperative BCTQ scores or postoperative changes in BCTQ scores. Postoperative median nerve CSA was not significantly correlated with postoperative BCTQ-S or BCTQ-F scores, and postoperative changes in median nerve CSA were not significantly correlated with postoperative changes in BCTQ-S or BCTQ-F scores. Conclusions The study shows clinical symptoms resolve rapidly after open CTR, but median nerve swelling and clinical function take several months to recover. In addition, preoperative median nerve swelling might predict preoperative severities of clinical symptoms and functional disabilities. However, postoperative reductions in median nerve swelling were not found to reflect postoperative reductions in clinical symptoms or functional disabilities. PMID:27583113

  3. A method for defining down-wind evacuation areas for transportation accidents involving toxic propellant spills

    NASA Technical Reports Server (NTRS)

    Siewert, R. D.

    1972-01-01

    Evacuation areas for accidental spills of toxic propellants along rail and highway shipping routes are defined to help local authorities reduce risks to people from excessive vapor concentrations. These criteria along with other emergency information are shown in propellant spill cards. The evacuation areas are based on current best estimates of propellant evaporation rates from various areas of spill puddles. These rates are used together with a continuous point-source, bi-normal model of plume dispersion. The rate at which the toxic plume disperses is based on a neutral atmospheric condition. This condition, which results in slow plume dispersion, represents the widest range of weather parameters which could occur during the day and nighttime periods. Evacuation areas are defined by the ground level boundaries of the plume within which the concentrations exceed the toxic Threshold Limit Value (TLV) or in some cases the Emergency Exposure Limit (EEL).

  4. Physical-chemical characterization of the particulate matter inside two road tunnels in the São Paulo Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Brito, J.; Rizzo, L. V.; Herckes, P.; Vasconcellos, P. C.; Caumo, S. E. S.; Fornaro, A.; Ynoue, R. Y.; Artaxo, P.; Andrade, M. F.

    2013-08-01

    The notable increase in biofuel usage by the road transportation sector in Brazil during recent years has significantly altered the vehicular fuel composition. Consequently, many uncertainties are currently found in particulate matter vehicular emission profiles. In an effort to better characterize the emitted particulate matter, measurements of aerosol physical and chemical properties were undertaken inside two tunnels located in the São Paulo Metropolitan Area (SPMA). The tunnels show very distinct fleet profiles: in the Jânio Quadros (JQ) tunnel, the vast majority of the circulating fleet are Light Duty Vehicles (LDVs), fuelled on average with the same amount of ethanol as gasoline. In the Rodoanel (RA) tunnel, the particulate emission is dominated by Heavy Duty Vehicles (HDVs) fuelled with diesel (5% biodiesel). In the JQ tunnel, PM2.5 concentration was on average 52 μg m-3, with the largest contribution of Organic Mass (OM, 42%), followed by Elemental Carbon (EC, 17%) and Crustal elements (13%). Sulphate accounted for 7% of PM2.5 and the sum of other trace elements was 10%. In the RA tunnel, PM2.5 was on average 233 μg m-3, mostly composed of EC (52%) and OM (39%). Sulphate, crustal and the trace elements showed a minor contribution with 5%, 1% and 1%, respectively. The average OC:EC ratio in the JQ tunnel was 1.59 ± 0.09, indicating an important contribution of EC despite the high ethanol fraction in the fuel composition. In the RA tunnel, the OC:EC ratio was 0.49 ± 0.12, consistent with previous measurements of diesel fuelled HDVs. Besides bulk carbonaceous aerosol measurement, Polycyclic Aromatic Hydrocarbons (PAHs) were quantified. The sum of the PAHs concentration was 56 ± 5 ng m-3 and 45 ± 9 ng m-3 in the RA and JQ tunnel, respectively. In the JQ tunnel, Benzo(a)pyrene (BaP) ranged from 0.9 to 6.7 ng m-3 (0.02-0.1‰ of PM2.5) in the JQ tunnel whereas in the RA tunnel BaP ranged from 0.9 to 4.9 ng m-3 (0.004-0.02‰ of PM2.5), indicating an

  5. Physical-chemical characterisation of the particulate matter inside two road tunnels in the São Paulo Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Brito, J.; Rizzo, L. V.; Herckes, P.; Vasconcellos, P. C.; Caumo, S. E. S.; Fornaro, A.; Ynoue, R. Y.; Artaxo, P.; Andrade, M. F.

    2013-12-01

    The notable increase in biofuel usage by the road transportation sector in Brazil during recent years has significantly altered the vehicular fuel composition. Consequently, many uncertainties are currently found in particulate matter vehicular emission profiles. In an effort to better characterise the emitted particulate matter, measurements of aerosol physical and chemical properties were undertaken inside two tunnels located in the São Paulo Metropolitan Area (SPMA). The tunnels show very distinct fleet profiles: in the Jânio Quadros (JQ) tunnel, the vast majority of the circulating fleet are light duty vehicles (LDVs), fuelled on average with the same amount of ethanol as gasoline. In the Rodoanel (RA) tunnel, the particulate emission is dominated by heavy duty vehicles (HDVs) fuelled with diesel (5% biodiesel). In the JQ tunnel, PM2.5 concentration was on average 52 μg m-3, with the largest contribution of organic mass (OM, 42%), followed by elemental carbon (EC, 17%) and crustal elements (13%). Sulphate accounted for 7% of PM2.5 and the sum of other trace elements was 10%. In the RA tunnel, PM2.5 was on average 233 μg m-3, mostly composed of EC (52%) and OM (39%). Sulphate, crustal and the trace elements showed a minor contribution with 5%, 1%, and 1%, respectively. The average OC : EC ratio in the JQ tunnel was 1.59 ± 0.09, indicating an important contribution of EC despite the high ethanol fraction in the fuel composition. In the RA tunnel, the OC : EC ratio was 0.49 ± 0.12, consistent with previous measurements of diesel-fuelled HDVs. Besides bulk carbonaceous aerosol measurement, polycyclic aromatic hydrocarbons (PAHs) were quantified. The sum of the PAHs concentration was 56 ± 5 ng m-3 and 45 ± 9 ng m-3 in the RA and JQ tunnel, respectively. In the JQ tunnel, benzo(a)pyrene (BaP) ranged from 0.9 to 6.7 ng m-3 (0.02-0.1‰ of PM2.5) whereas in the RA tunnel BaP ranged from 0.9 to 4.9 ng m-3 (0.004-0. 02‰ of PM2.5), indicating an important

  6. Methodology for Defining Gap Areas between Course-over-ground Locations

    SciTech Connect

    Wilson, John E.

    2013-09-30

    Finding all areas that lie outside some distance d from a polyline is a problem with many potential applications. This application of the Visual Sample Plan (VSP) software required finding all areas that were more than distance d from a set of existing paths (roads and trails) represented by polylines. An outer container polygon (known in VSP as a “sample area”) defines the extents of the area of interest. The term “gap area” was adopted for this project, but another useful term might be “negative coverage area.” The project required a polygon solution rather than a raster solution. The search for a general solution provided no results, so this methodology was developed

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

    SciTech Connect

    Zhang, Z. H. Bai, Lihui; Hu, C.-M.; Hemour, S.; Wu, K.; Fan, X. L.; Xue, D. S.; Houssameddine, D.

    2015-03-15

    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.

  8. Wind-tunnel Tests of the Fowler Variable-area Wing

    NASA Technical Reports Server (NTRS)

    Weick, Fred E; Platt, Robert C

    1932-01-01

    The lift, drag, and center of pressure characteristics of a model of the Fowler variable-area wing were measured in the NACA 7 by 10 foot wind tunnel. The Fowler wing consists of a combination of a main wing and an extension surface, also of airfoil section. The extension surface can be entirely retracted within the lower rear portion of the main wing or it can be moved to the rear and downward. The tests were made with the nose of the extension airfoil in various positions near the trailing edge of the main wing and with the surface at various angular deflections. The highest lift coefficient obtained was C(sub L) = 3.17 as compared with 1.27 for the main wing alone.

  9. Afferent Inputs to Neurotransmitter-Defined Cell Types in the Ventral Tegmental Area.

    PubMed

    Faget, Lauren; Osakada, Fumitaka; Duan, Jinyi; Ressler, Reed; Johnson, Alexander B; Proudfoot, James A; Yoo, Ji Hoon; Callaway, Edward M; Hnasko, Thomas S

    2016-06-21

    The ventral tegmental area (VTA) plays a central role in the neural circuit control of behavioral reinforcement. Though considered a dopaminergic nucleus, the VTA contains substantial heterogeneity in neurotransmitter type, containing also GABA and glutamate neurons. Here, we used a combinatorial viral approach to transsynaptically label afferents to defined VTA dopamine, GABA, or glutamate neurons. Surprisingly, we find that these populations received qualitatively similar inputs, with dominant and comparable projections from the lateral hypothalamus, raphe, and ventral pallidum. However, notable differences were observed, with striatal regions and globus pallidus providing a greater share of input to VTA dopamine neurons, cortical input preferentially on to glutamate neurons, and GABA neurons receiving proportionally more input from the lateral habenula and laterodorsal tegmental nucleus. By comparing inputs to each of the transmitter-defined VTA cell types, this study sheds important light on the systems-level organization of diverse inputs to VTA.

  10. Fire frequency, area burned, and severity: A quantitative approach to defining a normal fire year

    USGS Publications Warehouse

    Lutz, J.A.; Key, C.H.; Kolden, C.A.; Kane, J.T.; van Wagtendonk, J.W.

    2011-01-01

    Fire frequency, area burned, and fire severity are important attributes of a fire regime, but few studies have quantified the interrelationships among them in evaluating a fire year. Although area burned is often used to summarize a fire season, burned area may not be well correlated with either the number or ecological effect of fires. Using the Landsat data archive, we examined all 148 wildland fires (prescribed fires and wildfires) >40 ha from 1984 through 2009 for the portion of the Sierra Nevada centered on Yosemite National Park, California, USA. We calculated mean fire frequency and mean annual area burned from a combination of field- and satellite-derived data. We used the continuous probability distribution of the differenced Normalized Burn Ratio (dNBR) values to describe fire severity. For fires >40 ha, fire frequency, annual area burned, and cumulative severity were consistent in only 13 of 26 years (50 %), but all pair-wise comparisons among these fire regime attributes were significant. Borrowing from long-established practice in climate science, we defined "fire normals" to be the 26 year means of fire frequency, annual area burned, and the area under the cumulative probability distribution of dNBR. Fire severity normals were significantly lower when they were aggregated by year compared to aggregation by area. Cumulative severity distributions for each year were best modeled with Weibull functions (all 26 years, r2 ??? 0.99; P < 0.001). Explicit modeling of the cumulative severity distributions may allow more comprehensive modeling of climate-severity and area-severity relationships. Together, the three metrics of number of fires, size of fires, and severity of fires provide land managers with a more comprehensive summary of a given fire year than any single metric.

  11. Areas of cat auditory cortex as defined by neurofilament proteins expressing SMI-32.

    PubMed

    Mellott, Jeffrey G; Van der Gucht, Estel; Lee, Charles C; Carrasco, Andres; Winer, Jeffery A; Lomber, Stephen G

    2010-08-01

    The monoclonal antibody SMI-32 was used to characterize and distinguish individual areas of cat auditory cortex. SMI-32 labels non-phosphorylated epitopes on the high- and medium-molecular weight subunits of neurofilament proteins in cortical pyramidal cells and dendritic trees with the most robust immunoreactivity in layers III and V. Auditory areas with unique patterns of immunoreactivity included: primary auditory cortex (AI), second auditory cortex (AII), dorsal zone (DZ), posterior auditory field (PAF), ventral posterior auditory field (VPAF), ventral auditory field (VAF), temporal cortex (T), insular cortex (IN), anterior auditory field (AAF), and the auditory field of the anterior ectosylvian sulcus (fAES). Unique patterns of labeling intensity, soma shape, soma size, layers of immunoreactivity, laminar distribution of dendritic arbors, and labeled cell density were identified. Features that were consistent in all areas included: layers I and IV neurons are immunonegative; nearly all immunoreactive cells are pyramidal; and immunoreactive neurons are always present in layer V. To quantify the results, the numbers of labeled cells and dendrites, as well as cell diameter, were collected and used as tools for identifying and differentiating areas. Quantification of the labeling patterns also established profiles for ten auditory areas/layers and their degree of immunoreactivity. Areal borders delineated by SMI-32 were highly correlated with tonotopically-defined areal boundaries. Overall, SMI-32 immunoreactivity can delineate ten areas of cat auditory cortex and demarcate topographic borders. The ability to distinguish auditory areas with SMI-32 is valuable for the identification of auditory cerebral areas in electrophysiological, anatomical, and/or behavioral investigations.

  12. Epidemiology of human brucellosis in a defined area of Northwestern Greece.

    PubMed

    Avdikou, I; Maipa, V; Alamanos, Y

    2005-10-01

    Despite a European co-financial programme for control and eradication of brucellosis in Southern Europe, there is evidence that foci of brucellosis still exists in Greece and other Southern European countries. Human brucellosis cases are probably underreported in these countries. A local surveillance system was implemented in a defined region of Northwestern Greece, in order to record and study all human brucellosis cases, using several sources of retrieval. A total of 152 newly diagnosed cases were recorded during a 2-year study period (from 1 April 2002 to 31 March 2004). The age- and sex-adjusted mean annual incidence rate for the population of the study area was 17.3 cases/10(5) inhabitants. Incomplete application of the control and eradication programme in livestock, and the possible illegal trafficking of animals and their products across the Greek-Albanian border could be responsible for the persistence of foci of brucellosis in the area. PMID:16181512

  13. Epidemiology of human brucellosis in a defined area of Northwestern Greece.

    PubMed Central

    Avdikou, I.; Maipa, V.; Alamanos, Y.

    2005-01-01

    Despite a European co-financial programme for control and eradication of brucellosis in Southern Europe, there is evidence that foci of brucellosis still exists in Greece and other Southern European countries. Human brucellosis cases are probably underreported in these countries. A local surveillance system was implemented in a defined region of Northwestern Greece, in order to record and study all human brucellosis cases, using several sources of retrieval. A total of 152 newly diagnosed cases were recorded during a 2-year study period (from 1 April 2002 to 31 March 2004). The age- and sex-adjusted mean annual incidence rate for the population of the study area was 17.3 cases/10(5) inhabitants. Incomplete application of the control and eradication programme in livestock, and the possible illegal trafficking of animals and their products across the Greek-Albanian border could be responsible for the persistence of foci of brucellosis in the area. PMID:16181512

  14. Wind-tunnel Modelling of Dispersion from a Scalar Area Source in Urban-Like Roughness

    NASA Astrophysics Data System (ADS)

    Pascheke, Frauke; Barlow, Janet F.; Robins, Alan

    2008-01-01

    A wind-tunnel study was conducted to investigate ventilation of scalars from urban-like geometries at neighbourhood scale by exploring two different geometries a uniform height roughness and a non-uniform height roughness, both with an equal plan and frontal density of λ p = λ f = 25%. In both configurations a sub-unit of the idealized urban surface was coated with a thin layer of naphthalene to represent area sources. The naphthalene sublimation method was used to measure directly total area-averaged transport of scalars out of the complex geometries. At the same time, naphthalene vapour concentrations controlled by the turbulent fluxes were detected using a fast Flame Ionisation Detection (FID) technique. This paper describes the novel use of a naphthalene coated surface as an area source in dispersion studies. Particular emphasis was also given to testing whether the concentration measurements were independent of Reynolds number. For low wind speeds, transfer from the naphthalene surface is determined by a combination of forced and natural convection. Compared with a propane point source release, a 25% higher free stream velocity was needed for the naphthalene area source to yield Reynolds-number-independent concentration fields. Ventilation transfer coefficients w T / U derived from the naphthalene sublimation method showed that, whilst there was enhanced vertical momentum exchange due to obstacle height variability, advection was reduced and dispersion from the source area was not enhanced. Thus, the height variability of a canopy is an important parameter when generalising urban dispersion. Fine resolution concentration measurements in the canopy showed the effect of height variability on dispersion at street scale. Rapid vertical transport in the wake of individual high-rise obstacles was found to generate elevated point-like sources. A Gaussian plume model was used to analyse differences in the downstream plumes. Intensified lateral and vertical plume

  15. Atomic environment energies in proteins defined from statistics of accessible and contact surface areas.

    PubMed

    Delarue, M; Koehl, P

    1995-06-01

    Atomic contact potentials are derived by statistical analysis of atomic surface contact areas versus atom type in a database of non-homologous protein structures. The atomic environment is characterized by the surface area accessible to solvent and the surface of contacts with polar and non-polar atoms. Four types of atoms are considered, namely neutral polar atoms from protein backbones and from protein side-chains, non-polar atoms and charged atoms. Potential energies delta Ej(E) are defined from the preference for an atom of type j to be in a given environment E compared to the expected value if everything was random; Boltzmann's law is then used to transform these preferences into energies. These new potentials very clearly discriminate misfolded from correct structural models. The performance of these potentials are critically assessed by monitoring the recognition of the native fold among a large number of alternative structural folding types (the hide-and-seek procedure), as well as by testing if the native sequence can be recovered from a large number of randomly shuffled sequences for a given 3D fold (a procedure similar to the inverse folding problem). We suggest that these potentials reflect the atomic short range non-local interactions in proteins. To characterise atomic solvation alone, similar potentials were derived as a function of the percentage of solvent-accessible area alone. These energies were found to agree reasonably well with the solvation formalism of Eisenberg and McLachlan.

  16. A spatial multicriteria decision making tool to define the best agricultural areas for sewage sludge amendment.

    PubMed

    Passuello, Ana; Cadiach, Oda; Perez, Yolanda; Schuhmacher, Marta

    2012-01-01

    Sewage sludge amendment on agricultural soils has recently become a practice of heightened interest, as a consequence of sewage sludge production increase. This practice has benefits to soil and crops, however it may also lead to environmental contamination, depending on the characteristics of the fields. In order to define the suitability of the different agricultural fields to receive sewage sludge, a spatial tool is proposed. This tool, elaborated in GIS platform, aggregates different criteria regarding human exposure and environmental contamination. The spatial tool was applied to a case study in the region of Catalonia (NE of Spain). Within the case study, each step of the tool development is detailed. The results show that the studied region has different suitability degrees, being the appropriate areas sufficient for receiving the total amount of sewage sludge produced. The sensitivity analysis showed that "groundwater contamination", "distance to urban areas", "metals concentration in soil" and "crop type" are the most important criteria of the evaluation. The developed tool successfully tackled the problem, providing a comprehensive procedure to evaluate agricultural land suitability to receive sewage sludge as an organic fertilizer. Also, the tool implementation gives insights to decision makers, guiding them to more confident decisions, based on an extensive group of criteria.

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

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

    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.

  18. Recognition Tunneling

    PubMed Central

    Lindsay, Stuart; He, Jin; Sankey, Otto; Hapala, Prokop; Jelinek, Pavel; Zhang, Peiming; Chang, Shuai; Huang, Shuo

    2010-01-01

    Single molecules in a tunnel junction can now be interrogated reliably using chemically-functionalized electrodes. Monitoring stochastic bonding fluctuations between a ligand bound to one electrode and its target bound to a second electrode (“tethered molecule-pair” configuration) gives insight into the nature of the intermolecular bonding at a single molecule-pair level, and defines the requirements for reproducible tunneling data. Simulations show that there is an instability in the tunnel gap at large currents, and this results in a multiplicity of contacts with a corresponding spread in the measured currents. At small currents (i.e. large gaps) the gap is stable, and functionalizing a pair of electrodes with recognition reagents (the “free analyte” configuration) can generate a distinct tunneling signal when an analyte molecule is trapped in the gap. This opens up a new interface between chemistry and electronics with immediate implications for rapid sequencing of single DNA molecules. PMID:20522930

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

    PubMed

    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.

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

    PubMed Central

    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. PMID

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

    PubMed

    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. PMID

  2. Comparison of options for reduction of noise in the test section of the NASA Langley 4x7m wind tunnel, including reduction of nozzle area

    NASA Technical Reports Server (NTRS)

    Hayden, R. E.

    1984-01-01

    The acoustically significant features of the NASA 4X7m wind tunnel and the Dutch-German DNW low speed tunnel are compared to illustrate the reasons for large differences in background noise in the open jet test sections of the two tunnels. Also introduced is the concept of reducing test section noise levels through fan and turning vane source reductions which can be brought about by reducing the nozzle cross sectional area, and thus the circuit mass flow for a particular exit velocity. The costs and benefits of treating sources, paths, and changing nozzle geometry are reviewed.

  3. Wide-field retinotopy defines human cortical visual area v6.

    PubMed

    Pitzalis, Sabrina; Galletti, Claudio; Huang, Ruey-Song; Patria, Fabiana; Committeri, Giorgia; Galati, Gaspare; Fattori, Patrizia; Sereno, Martin I

    2006-07-26

    The retinotopic organization of a newly identified visual area near the midline in the dorsalmost part of the human parieto-occipital sulcus was mapped using high-field functional magnetic resonance imaging, cortical surface-based analysis, and wide-field retinotopic stimulation. This area was found in all 34 subjects that were mapped. It represents the contralateral visual hemifield in both hemispheres of all subjects, with upper fields located anterior and medial to areas V2/V3, and lower fields medial and slightly anterior to areas V3/V3A. It contains a representation of the center of gaze distinct from V3A, a large representation of the visual periphery, and a mirror-image representation of the visual field. Based on similarity in position, visuotopic organization, and relationship with the neighboring extrastriate visual areas, we suggest it might be the human homolog of macaque area V6, and perhaps of area M (medial) or DM (dorsomedial) of New World primates.

  4. Si nanowires by a single-step metal-assisted chemical etching process on lithographically defined areas: formation kinetics

    PubMed Central

    2011-01-01

    In this paper, we investigate the formation kinetics of Si nanowires [SiNWs] on lithographically defined areas using a single-step metal-assisted chemical etching process in an aqueous HF/AgNO3 solution. We show that the etch rate of Si, and consequently, the SiNW length, is much higher on the lithographically defined areas compared with that on the non-patterned areas. A comparative study of the etch rate in the two cases under the same experimental conditions showed that this effect is much more pronounced at the beginning of the etching process. Moreover, it was found that in both cases, the nanowire formation rate is linear with temperature in the range from 20°C to 50°C, with almost the same activation energy, as obtained from an Arrhenius plot (0.37 eV in the case of non-patterned areas, while 0.38 eV in the case of lithographically patterned areas). The higher etch rate on lithographically defined areas is mainly attributed to Si surface modification during the photolithographic process. PACS: 68; 68.65-k. PMID:22087735

  5. The afferent and efferent callosal connections of retinotopically defined areas in cat cortex

    SciTech Connect

    Segraves, M.A.; Rosenquist, A.C.

    1982-08-01

    We compared the callosal afferent and efferent connections of different retinotopic loci within a given visual cortical area as well as the connectivity patterns among similar retinotopic loci in different visual areas. Small injections (75 nl) of a mixture of horseradish peroxidase and (/sup 3/H)leucine were made through a recording pipette at injection sites identified by retinotopic mapping. A small locus of cortex within a callosally connected region had precise reciprocal connections with the homotopic locus in the contralateral hemisphere. This small locus also was callosally connected with a variable number of heterotopic loci. Both reciprocal and nonreciprocal heterotopic callosal connections were found. Homotopic and heterotopic connections appeared to have a high degree of retinotopic fidelity. Precisely homotopic connections were present not only between locations on the vertical meridian representations at the left and right area 17/18 borders but also, for example, between mirror-symmetrical points on the peripheral horizontal meridian representation in the left and right posteromedial lateral suprasylvian areas. In several experiments, we found that both callosal neurons and terminals in the homotopic cortex were grouped into two to three distinct clusters ranging from 600 to 900 micrometers in width. Callosal neurons with homotopic connections were primarily pyramidal cells in lower layer III and upper layer IV. Outside of areas 17 and 18, there was a significant number of pyramidal and fusiform-shaped callosal neurons in layers V and VI. The majority of callosal terminals were located in layers II, III, and IV.

  6. The new hospice compliance plan: defining and addressing risk areas. Part 2.

    PubMed

    Jones, D H; Woods, K

    2000-06-01

    The Department of Health and Human Services' (HHS) Office of the Inspector General (OIG), has advised hospices and other health care providers to formulate effective controls to ensure compliance with federal and state statutes, rules, and regulations, and private-payor health care program requirements. This is the second of three installments that focus specifically on the 28 risk areas identified in the guidance and offer strategies for incorporating them in a hospice compliance program. This article covers the areas of Expensive Care, Documentation, Interdisciplinary Group, and Kickbacks.

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

    Code of Federal Regulations, 2010 CFR

    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...

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

    SciTech Connect

    NSTec Environmental Restoration

    2008-11-01

    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.

  9. Sexual child abuse in a defined Swedish area 1993-97: a population-based survey.

    PubMed

    Carlstedt, A; Forsman, A; Soderstrom, H

    2001-10-01

    Attempting to avoid some of the most common methodological problems involved in research on sexual child abuse, we collected data on crimes, perpetrators, and sanctions in all convicted cases of sexual child abuse in a defined population during a 5-year period. This approach provided amply documented and ascertained cases with precise definitions and descriptions of the crimes involved, no clinical referral bias, and minimal dependence on memory effects. The results are valid for the small proportion of cases that lead to conviction in the context of Swedish legislation. Structured data were collected from the court dossiers in all cases of sexual crimes against minors (less than 15 years of age) tried and sentenced at the courts in the Västra Götaland region of Sweden between 1993 and 1997. The total number of 496 sentences for sexual crimes during the study period included 203 cases of sexual child abuse (40.8%) with 283 victims and 196 perpetrators, all men. Girls were victims in 85% of the cases, boys in 12%, and boys as well as girls in 3%. Sexual penetration had occurred in 54.5% of cases and the total proportion of hands-on crimes was 83%. Most perpetrators, 72%, were well known to the child. The most severe offenses took place within the family. A wide range of acts were classified as sexual child abuse, but most common was sexual penetration of a female child by her biological father or a family friend. PMID:11501297

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

    PubMed

    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.

  11. Use of ground penetrating radar to define recharge areas in the Central Sand Plain

    NASA Astrophysics Data System (ADS)

    Bohling, Geoffrey C.; Anderson, Mary P.; Bentley, Charles R.

    Contamination of groundwater by agricultural chemicals in the Central Sand Plain (Portage County in Wisconsin) has prompted studies of groundwater flow in the region. Because the groundwater system is particularly susceptible to contamination in areas where groundwater recharge occurs, identification of recharge zones can contribute significantly to the effective management of agricultural chemical use. An accurate map of water table elevation (groundwater head) is crucial to identifying the distribution of recharge. The reliability of ground penetrating radar as a total for obtaining high resolution maps of water table elevation was assessed. Sparse subsets of wells in the area were used to calibrate the radar. Water table depths obtained from these calibrations were compared to known water table depths in the remaining wells. Three wells are the minimum needed to obtain an estimate of uncertainty in calibration parameters; specifically the radar signal velocity in the subsurface materials and the return time correction factor. If several wells distributed throughout a region of interest yield consistent calibration results, radar can be used to produce a map of water table elevation for that region.

  12. The availability of extrinsic handgun locking devices in a defined metro area.

    PubMed

    Milne, J S; Hargarten, S W

    1999-11-01

    Extrinsic safety devices, such as trigger locks, have been central in the recent state discussions on how to reduce firearm injuries. The actual prevalence of handgun locking devices in the consumer market, however, is unknown. This study catalogued the extrinsic safety devices available from handgun dealers and discount retail chains in Milwaukee, WI. We found that all locations studied (n = 13) stock at least 1 type of extrinsic safety device. A total of 21 unique models of safety devices were stocked by the 13 locations, with trigger locks being the most common (n = 9). Other types of devices included lock-boxes (n = 5), cable locks (n = 4), hammer locks (n = 1), barrel locks (n = 1), and a rubber slide strap (n = 1). Handgun owners in the Milwaukee metro area have a selection of extrinsic handgun safety devices available from handgun dealers and discount retailers. However, there does not appear to be a consistent availability on type of device.

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

    SciTech Connect

    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.

  14. A plastic relationship between vinculin-mediated tension and adhesion complex area defines adhesion size and lifetime

    NASA Astrophysics Data System (ADS)

    Hernández-Varas, Pablo; Berge, Ulrich; Lock, John G.; Strömblad, Staffan

    2015-06-01

    Cell-matrix adhesions are central mediators of mechanotransduction, yet the interplay between force and adhesion regulation remains unclear. Here we use live cell imaging to map time-dependent cross-correlations between vinculin-mediated tension and adhesion complex area, revealing a plastic, context-dependent relationship. Interestingly, while an expected positive cross-correlation dominated in mid-sized adhesions, small and large adhesions display negative cross-correlation. Furthermore, although large changes in adhesion complex area follow vinculin-mediated tension alterations, small increases in area precede vinculin-mediated tension dynamics. Modelling based on this mapping of the vinculin-mediated tension-adhesion complex area relationship confirms its biological validity, and indicates that this relationship explains adhesion size and lifetime limits, keeping adhesions focal and transient. We also identify a subpopulation of steady-state adhesions whose size and vinculin-mediated tension become stabilized, and whose disassembly may be selectively microtubule-mediated. In conclusion, we define a plastic relationship between vinculin-mediated tension and adhesion complex area that controls fundamental cell-matrix adhesion properties.

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

    SciTech Connect

    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 {approx} 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.

  16. How Sensitive Are Multilevel Regression Findings to Defined Area of Context? A Case Study of Mammography Use in California

    PubMed Central

    Mobley, Lee R.; Kuo, Tzy-Mey (May); Andrews, Linda

    2009-01-01

    The authors develop a hybrid model of health care use that blends features of the traditional Aday–Andersen behavioral model with the socioecological modeling perspective. They use the model to conceptualize the various levels of influence expected from socioecological variables in individuals’ mammography use decisions, build contextual variables from fine-grained data into four different types of geographic areas, and then use two- and three-level modeling of personal and area-level contextual factors to explain observed behavior. The central focus is on whether differentiating the conceptualized levels of influence seems to materially affect regression findings. The test could conceivably be confounded by the modifiable areal unit problem, but little evidence for this is found. Findings for California women suggest that distinctions do matter in how the levels of influence are defined for local neighborhood contextual factors. Studies using only county-level contextual factors will miss some meaningful associations related to interpersonal/proximate-level factors. PMID:18259047

  17. Plan of study to define hydrogeologic characteristics of the Madera Limestone in the east mountain area of central New Mexico

    USGS Publications Warehouse

    Rankin, D.R.

    1999-01-01

    The east mountain area of central New Mexico includes the eastern one-third of Bernalillo County and portions of Sandoval, Santa Fe, and Torrance Counties. The area covers about 320 square miles. The Madera Limestone, the principal aquifer in the east mountain area, is the sole source of water for domestic, municipal, industrial, and agricultural uses for many residents. Some water is imported from wells near Edgewood by the Entranosa Water Cooperative, which serves a population of approximately 3,300. The remaining population is served by small water systems that derive supplies locally or by individually owned domestic wells. The population of the east mountain area has increased dramatically over the past 20 years. In 1970, the population of the east mountain area was about 4,000. Demographic projections suggest that approximately 1,000 people per year are moving into the area, and with a growth rate of 3.0 percent the population will be 16,700 in 2000. Consequently, ground-water withdrawals have increased substantially over the past 20 years, and will continue to increase. Little is known about the flow characteristics and hydrogeologic properties of the Madera Limestone. This report describes existing information about the geologic and hydrologic framework and flow characteristics of the Madera Limestone, and presents a plan of study for data-collection activities and interpretive studies that could be conducted to better define the hydrogeologic characteristics of the Madera Limestone. Data-collection activities and interpretive studies related to the hydrogeologic components of the Madera Limestone are prioritized. Activities that are necessary to improve the quantification of a component are prioritized as essential. Activities that could add additional understanding of a component, but would not be necessary to improve the quantification of a component, are prioritized as useful.

  18. Wind-tunnel and Flight Investigations of the Use of Leading-Edge Area Suction for the Purpose of Increasing the Maximum Lift Coefficient of a 35 Degree Swept-Wing Airplane

    NASA Technical Reports Server (NTRS)

    Holzhauser, Curt A; Bray, Richard S

    1956-01-01

    An investigation was undertaken to determine the increase in maximum lift coefficient that could be obtained by applying area suction near the leading edge of a wing. This investigation was performed first with a 35 degree swept-wing model in the wind tunnel, and then with an operational 35 degree swept-wing airplane which was modified in accord with the wind-tunnel results. The wind-tunnel and flight tests indicated that the maximum lift coefficient was increased more than 50 percent by the use of area suction. Good agreement was obtained in the comparison of the wind-tunnel results with those measured in flight.

  19. Hazard connected to tunnel construction in Mt Stena karstic area (Rosandra Valley, Classical Karst)

    NASA Astrophysics Data System (ADS)

    Cucchi, F.; Boschin, W.; Visintin, L.; Zini, L.

    2009-04-01

    Rosandra Valley -a unique geomorphological environment- is located in the western side of the Classical Karst plateau. This deep limestone gorge is crossed by a stream that is fed by a large basin located in Slovenia. Rosandra Valley is the only example of Classical Karst river valley with surface hydrography; the torrent digs a deep gully into the rock, rich in rapids, swirl holes, small waterfalls, enclosed meanders and basins; here, the first seepage phenomena occur, and part of the water feeds the underground aquifer. Rosandra Valley is theatre to complex structural situation; the NE slope culminates in the structure of Mt Stena, a limestone tectonic scale located between two faults and firmly rooted in the karst platform. Tectonics is quite important for the development of deep karst in this area; Mt Stena, in particular, hosts a comprehensive net of articulated and diversely shaped caves, basically organised on several levels, which stretches over a total of 9,000 metres, bearing testimony to ancient geological and hydrogeological origins. The deepest areas of the system reach a suspended aquifer that is probably sustained by an overthrust and placed about 100 meters above Rosandra torrent underground aquifer. During feasibility studies about Trieste-Divača high velocity railway link, interaction between project and karst features was examined; in fact the proximity of proposal project and Mt Stena karst system suggest to improve the knowledge related to karst and hydrogeological aspects of the massif. Compatibly with the project requirements, risk of voids intersection and water contamination were analyzed. In fact the Mt Stena suspended aquifer partially feeds Rosandra torrent which flows in a protected natural area. Karst features were represented in a 3D model in order to better understand the spatial relationship between railway project and karst system.

  20. Assessing spatial and nonspatial factors for healthcare access: towards an integrated approach to defining health professional shortage areas.

    PubMed

    Wang, Fahui; Luo, Wei

    2005-06-01

    This research considers both spatial and nonspatial factors in examining accessibility to primary healthcare in Illinois. Spatial access emphasizes the importance of geographic barrier between consumer and provider, and nonspatial factors include nongeographic barriers or facilitators such as age, sex, ethnicity, income, social class, education and language ability. The population and socioeconomic data are from the 2000 Census, and the primary care physician data for the same year are provided by the American Medical Association. First, a two-step floating catchment area method implemented in Geographic Information Systems is used to measure spatial accessibility based on travel time. Secondly, the factor analysis method is used to group various sociodemographic variables into three factors: (1) socioeconomic disadvantages, (2) sociocultural barriers and (3) high healthcare needs. Finally, spatial and nonspatial factors are integrated to identify areas with poor access to primary healthcare. The research is intended to develop an integrated approach for defining Health Professional Shortage Areas (HPSA) that may help the US Department of Health and Human Services and state health departments improve HPSA designation. PMID:15629681

  1. slc7a6os Gene Plays a Critical Role in Defined Areas of the Developing CNS in Zebrafish

    PubMed Central

    Benini, Anna; Cignarella, Francesca; Calvarini, Laura; Mantovanelli, Silvia; Giacopuzzi, Edoardo; Zizioli, Daniela; Borsani, Giuseppe

    2015-01-01

    The aim of this study is to shed light on the functional role of slc7a6os, a gene highly conserved in vertebrates. The Danio rerio slc7a6os gene encodes a protein of 326 amino acids with 46% identity to human SLC7A6OS and 14% to Saccharomyces cerevisiae polypeptide Iwr1. Yeast Iwr1 specifically binds RNA pol II, interacts with the basal transcription machinery and regulates the transcription of specific genes. In this study we investigated for the first time the biological role of SLC7A6OS in vertebrates. Zebrafish slc7a6os is a maternal gene that is expressed throughout development, with a prevalent localization in the developing central nervous system (CNS). The gene is also expressed, although at different levels, in various tissues of the adult fish. To determine the functional role of slc7a6os during zebrafish development, we knocked-down the gene by injecting a splice-blocking morpholino. At 24 hpf morphants show morphological defects in the CNS, particularly the interface between hindbrain and midbrain is not well-defined. At 28 hpf the morpholino injected embryos present an altered somite morphology and appear partially or completely immotile. At this stage the midbrain, hindbrain and cerebellum are compromised and not well defined compared with control embryos. The observed alterations persist at later developmental stages. Consistently, the expression pattern of two markers specifically expressed in the developing CNS, pax2a and neurod, is significantly altered in morphants. The co-injection of embryos with synthetic slc7a6os mRNA, rescues the morphant phenotype and restores the wild type expression pattern of pax2a and neurod. Our data suggest that slc7a6os might play a critical role in defined areas of the developing CNS in vertebrates, probably by regulating the expression of key genes. PMID:25803583

  2. New Mecyclothorax spp. (Coleoptera, Carabidae, Moriomorphini) define Mont Mauru, eastern Tahiti Nui, as a distinct area of endemism

    PubMed Central

    Liebherr, James K.

    2012-01-01

    Abstract Seven species of Mecyclothorax Sharp precinctive to Mont Mauru, Tahiti, Society Islands are newly described: Mecyclothorax tutei sp. n., Mecyclothorax tihotii sp. n., Mecyclothorax putaputa sp. n., Mecyclothorax toretore sp. n., Mecyclothorax anaana sp. n., Mecyclothorax pirihao sp. n., and Mecyclothorax poro sp. n. These seven constitute the first representative Mecyclothorax species recorded from Mauru, and their geographic restriction to this isolated massif defines it as a distinct area of endemism along the highly dissected eastern versant of the Tahiti Nui volcano. Each of the new species has a closest relative on another massif of Tahiti Nui, supporting speciation associated with vicariance caused by extensive erosional valley formation, especially the development of Papenoo Valley. Comparison of the known elevational distributions of the new discoveries on Mont Mauru to the elevational diversity profile of the comparatively well-sampled Mont Marau, northwest Tahiti Nui, suggests that numerous Mecyclothorax species remain to be discovered in higher-elevation habitats of Mont Mauru. PMID:23166465

  3. Soil Quality Indicators to Define Land Use in the Area of Native Forest of Entre Ríos, Argentina

    NASA Astrophysics Data System (ADS)

    Wilson, M. G.; Tasi, H. A.; Paz González, A.; Díaz, E. L.; Sasal, M. C.

    2012-04-01

    The main economic activity in the area of native forest of the province of Entre Ríos (Argentina) has long been the agricultural and/or livestock production, especially cattle breeding. In recent years, the proportion of agricultural crops in the rotations, especially that of soybean, has increased, thus leading to an increase in the need for land clearing to incorporate new lands for agricultural use. Most of these lands are considered marginal for agricultural use. In addition rice farming with irrigation is a critical part of the Entre Ríos economy. Defining and assessing soil quality indicators (SQI) that show the evolution of the soil with different uses and management systems is a way to contribute to the knowledge of soil quality. The aims of this study were to characterize the current land use and land tenure in the area of native forest of Entre Ríos, as well as to identify and select variables sensitive to agricultural and/or livestock use of the most representative soils of this area (indicators of the dynamic quality of the soil) and define the most appropriate land use according to land suitability and behavior of these indicators. We identified the most representative soil subgroups (corresponding to the orders Vertisols, Mollisols and Alfisols) and defined the production systems livestock-agricultural, agricultural-livestock, agricultural without irrigation, and rice crop irrigated with water from groundwater and surface reservoirs. We also determined the physical, physico-chemical, chemical and microbiological variables of the soil, and characterized the quality of the water for irrigation. We selected the SQI using Principal Components Analysis, to form a minimum data set (MDS). The change in the use of the land responded to a favorable economic situation for agriculture that started in the 1990's. The leasing and sharecropping schemes and the incidental contracts have become increasingly important, predominating over the undivided property. We

  4. Moving beyond the variable source area concept for defining the hydrologic and geomorphic process controls on water quality

    NASA Astrophysics Data System (ADS)

    McDonnell, J. J.

    2003-12-01

    A variety of hydrologic and geomorphic processes influence surface water quality via event-based flushing of labile nutrient stores and between-event weathering reactions along subsurface flowpaths. A central paradigm in our modeling of these processes rests with the Variable Source Area concept, articulated by John Hewlett almost 50 years ago. Rapid progress is being made on the water quality modeling front modeling vis-…-vis parameter estimation techniques, model uncertainty analysis, examination of parameter identifiability in our models, downward approaches to hydrologic prediction, etc,. However, I wonder if we have neglected somewhat, updating our understanding of the rainfall-runoff process and the basic questions of: Where does water go when it rains? What flow path does it take to the stream? How long does it reside in the catchment? These questions, while basic, lie at the heart of understanding the coupled hydrologic and geomorphic processes influencing water quality. This talk will explore how our sharpening perception of water source, flowpath and age in upland headwater catchments is increasingly at odds with variable source area theory. The variable source area concept has been distilled into our widely used research model structures by collapsing the process complexity into simple mathematical assumptions of things like the decline in saturated hydraulic conductivity with depth, steady-state catchment water table response, topographically defined water flowpaths and linear wetting and drying from the valley bottom upwards to the ridge (depending upon storm size, intensity and antecedent wetness conditions). This talk takes a critical look at our process underpinning by discussing new field evidence of where water goes when it rains that directly challenges the status quo. New model structures informed by this new process understanding are then discussed in the context of how data and objective hydrologic and geomorphic discretization of catchment

  5. Scanning tunneling microscope nanoetching method

    DOEpatents

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  7. Standardization of flux chamber and wind tunnel flux measurements for quantifying emissions from area sources at animal feeding operations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A variety of wind tunnels and flux chambers have been used to measure fluxes of volatile organic compounds (VOC) and ammonia (NH3) at animal feeding operations (AFO). However, there has been little regard to the extreme variation and inaccuracy caused by inappropriate air velocity or sweep air flow...

  8. Wind tunnels vs. flux chambers: Area source emission measurements and the necessity for VOC and odour correction factors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind tunnels and flux chambers have been used to measure fluxes of volatile organic compounds (VOC), odour, and ammonia (NH3) with little regard to air velocity or sweep air flow rates. As a result, flux measurements have been highly variable and scientists have been in disagreement as to the better...

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

    ERIC Educational Resources Information Center

    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…

  10. Particle surface area dependence of mineral dust in immersion freezing mode: investigations with freely suspended drops in an acoustic levitator and a vertical wind tunnel

    NASA Astrophysics Data System (ADS)

    Diehl, K.; Debertshäuser, M.; Eppers, O.; Schmithüsen, H.; Mitra, S. K.; Borrmann, S.

    2014-11-01

    The heterogeneous freezing temperatures of supercooled drops were measured using an acoustic levitator. This technique allows one to freely suspend single drops in the air without any wall contact. Heterogeneous nucleation by two types of illite (illite IMt1 and illite NX) and a montmorillonite sample was investigated in the immersion mode. Drops of 1 mm in radius were monitored by a video camera while cooled down to -28 °C to simulate freezing within the tropospheric temperature range. The surface temperature of the drops was contact-free, determined with an infrared thermometer; the onset of freezing was indicated by a sudden increase of the drop surface temperature. For comparison, measurements with one particle type (illite NX) were additionally performed in the Mainz vertical wind tunnel with drops of 340 μm radius freely suspended. Immersion freezing was observed in a temperature range between -13 and -26 °C as a function of particle type and particle surface area immersed in the drops. Isothermal experiments in the wind tunnel indicated that after the cooling stage freezing still proceeds, at least during the investigated time period of 30 s. The results were evaluated by applying two descriptions of heterogeneous freezing, the stochastic and the singular model. Although the wind tunnel results do not support the time-independence of the freezing process both models are applicable for comparing the results from the two experimental techniques.

  11. Defining cure.

    PubMed

    Hilton, Paul; Robinson, Dudley

    2011-06-01

    This paper is a summary of the presentations made as Proposal 2-"Defining cure" to the 2nd Annual meeting of the ICI-Research Society, in Bristol, 16th June 2010. It reviews definitions of 'cure' and 'outcome', and considers the impact that varying definition may have on prevalence studies and cure rates. The difference between subjective and objective outcomes is considered, and the significance that these different outcomes may have for different stakeholders (e.g. clinicians, patients, carers, industry etc.) is discussed. The development of patient reported outcome measures and patient defined goals is reviewed, and consideration given to the use of composite end-points. A series of proposals are made by authors and discussants as to how currently validated outcomes should be applied, and where our future research activity in this area might be directed.

  12. TOPICAL REVIEW: Recognition tunneling

    NASA Astrophysics Data System (ADS)

    Lindsay, Stuart; He, Jin; Sankey, Otto; Hapala, Prokop; Jelinek, Pavel; Zhang, Peiming; Chang, Shuai; Huang, Shuo

    2010-07-01

    Single molecules in a tunnel junction can now be interrogated reliably using chemically functionalized electrodes. Monitoring stochastic bonding fluctuations between a ligand bound to one electrode and its target bound to a second electrode ('tethered molecule-pair' configuration) gives insight into the nature of the intermolecular bonding at a single molecule-pair level, and defines the requirements for reproducible tunneling data. Simulations show that there is an instability in the tunnel gap at large currents, and this results in a multiplicity of contacts with a corresponding spread in the measured currents. At small currents (i.e. large gaps) the gap is stable, and functionalizing a pair of electrodes with recognition reagents (the 'free-analyte' configuration) can generate a distinct tunneling signal when an analyte molecule is trapped in the gap. This opens up a new interface between chemistry and electronics with immediate implications for rapid sequencing of single DNA molecules.

  13. CORRECTIVE ACTION DECISION DOCUMENT FOR CORRECTIVE ACTION UNIT 383: AREA 12 E-TUNNEL SITES, NEVADA TEST SITE, REV. NO. 0

    SciTech Connect

    Mark McLane

    2005-03-01

    This Corrective Action Decision Document (CADD) was prepared by the Defense Threat Reduction Agency (DTRA) and the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO). The recommendations and corrective actions described within this document apply to the future closure of Corrective Action Unit (CAU) 383, Area 12 E-Tunnel Sites, which is a joint DTRA and NNSA/NSO site. The CAU consists of three (3) Corrective Action Sites (CASs): CAS 12-06-06 (Muckpile); CAS 12-25-02 (Oil Spill); and CAS 12-28-02 (Radioactive Material). In addition to these CASs, E-Tunnel Ponds One, Two, and Three, and the Drainage Area above the ponds were included since closure of the Muckpile will impact these areas. This CADD is consistent with the requirements of the ''Federal Facility Agreement and Consent Order'' agreed to by the State of Nevada, the U.S. Department of Energy, and the U.S. Department of Defense. The DTRA point of contact is the Nevada Operations Office, Environmental Project Manager; currently Ms. Tiffany A. Lantow. The NNSA/NSO point of contact is the Environmental Restoration, Industrial Sites Project Manager; currently Ms. Janet Appenzeller-Wing. The purpose of this CADD is to identify and provide the rationale for the selection of a recommended corrective action alternative for CAU 383. This document presents the recommended corrective action for CAU 383 (E-Tunnel Sites); however, implementation may be affected by the corrective action (to be determined) for CAU 551 (Area 12 Muckpiles) due to the close proximity of B, C, D, and F-Tunnels. The scope of this CADD consists of the following tasks: (1) Develop corrective action objectives; (2) Identify corrective action alternative screening criteria; (3) Develop corrective action alternatives; (4) Perform detailed and comparative evaluations of the corrective action alternatives in relation to the corrective action objectives and screening criteria; and (5) Recommend and justify

  14. Use of automatic extraction of LANDSAT data defining areas of ilmenite in the forest of the state of Pernambuco. [Brazil

    NASA Technical Reports Server (NTRS)

    Dejesusparada, N. (Principal Investigator); Mattoso, S. D. Q.; Paradella, W. R.; Meneses, P. R.

    1979-01-01

    The author has identified the following significant results. Classification results point out 600 alarm areas of high potentiality of titanium occurrence. Almost 80 of these 600 alarm areas were checked by field work, and in 56 of them, titanium occurrences were confirmed and four new ore deposits were found.

  15. The rationale for attempting to define salt marsh mosquito-breeding areas in Galveston County by remote sensing the associated vegetation

    NASA Technical Reports Server (NTRS)

    Arp, G. K.

    1975-01-01

    The rationale for attempting to define salt marsh mosquito breeding areas in Galveston County was discussed, including a botanical survey of the marsh plant communities, their relationship to flooding, and their exposure to salt water. Particular emphasis is given to Distichlis spicata, a widespread marsh grass. Evidence suggests that breeding areas of Aedes sollicitans are associated with Distichlis and that both species respond to similar ecological conditions in the salt marsh. Aspects of the remote sensing of the Distichlis are considered.

  16. Enhancing Learning: From Access to Success. Report of the First Experts' Meeting: Defining Areas of Action (Paris, France, March 26-28, 2007)

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific and Cultural Organization (UNESCO), 2007

    2007-01-01

    This document is a summary of the "First Experts' Meeting: Defining Areas of Action to Enhance Learning--From Access to Success," which took place at UNESCO Headquarters from March 26 to 28, 2007. The meeting brought together some 30 experts from around the world including researchers, educators, educational planners, representatives of United …

  17. A Transcription Factor Code Defines Nine Sensory Interneuron Subtypes in the Mechanosensory Area of the Spinal Cord

    PubMed Central

    Del Barrio, Marta Garcia; Bourane, Steeve; Grossmann, Katja; Schüle, Roland; Britsch, Stefan; O’Leary, Dennis D.M.; Goulding, Martyn

    2013-01-01

    Interneurons in the dorsal spinal cord process and relay innocuous and nociceptive somatosensory information from cutaneous receptors that sense touch, temperature and pain. These neurons display a well-defined organization with respect to their afferent innervation. Nociceptive afferents innervate lamina I and II, while cutaneous mechanosensory afferents primarily innervate sensory interneurons that are located in lamina III–IV. In this study, we outline a combinatorial transcription factor code that defines nine different inhibitory and excitatory interneuron populations in laminae III–IV of the postnatal cord. This transcription factor code reveals a high degree of molecular diversity in the neurons that make up laminae III–IV, and it lays the foundation for systematically analyzing and manipulating these different neuronal populations to assess their function. In addition, we find that many of the transcription factors that are expressed in the dorsal spinal cord at early postnatal times continue to be expressed in the adult, raising questions about their function in mature neurons and opening the door to their genetic manipulation in adult animals. PMID:24223744

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

    SciTech Connect

    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.

  19. Bulk regional viral injection in neonatal mice enables structural and functional interrogation of defined neuronal populations throughout targeted brain areas.

    PubMed

    Cheetham, Claire E J; Grier, Bryce D; Belluscio, Leonardo

    2015-01-01

    The ability to label and manipulate specific cell types is central to understanding the structure and function of neuronal circuits. Here, we have developed a simple, affordable strategy for labeling of genetically defined populations of neurons throughout a targeted brain region: Bulk Regional Viral Injection (BReVI). Our strategy involves a large volume adeno-associated virus (AAV) injection in the targeted brain region of neonatal Cre driver mice. Using the mouse olfactory bulb (OB) as a model system, we tested the ability of BReVI to broadly and selectively label tufted cells, one of the two principal neuron populations of the OB, in CCK-IRES-Cre mice. BReVI resulted in labeling of neurons throughout the injected OB, with no spatial bias toward the injection site and no evidence of damage. The specificity of BReVI labeling was strikingly similar to that seen previously using immunohistochemical staining for cholecystokinin (CCK), an established tufted cell marker. Hence, the CCK-IRES-Cre line in combination with BReVI can provide an important tool for targeting and manipulation of OB tufted cells. We also found robust Cre-dependent reporter expression within three days of BReVI, which enabled us to assess developmental changes in the number and laminar distribution of OB tufted cells during the first three postnatal weeks. Furthermore, we demonstrate that BReVI permits structural and functional imaging in vivo, and can be combined with transgenic strategies to facilitate multi-color labeling of neuronal circuit components. BReVI is broadly applicable to different Cre driver lines and can be used to regionally manipulate genetically defined populations of neurons in any accessible brain region. PMID:26594154

  20. Bulk regional viral injection in neonatal mice enables structural and functional interrogation of defined neuronal populations throughout targeted brain areas

    PubMed Central

    Cheetham, Claire E. J.; Grier, Bryce D.; Belluscio, Leonardo

    2015-01-01

    The ability to label and manipulate specific cell types is central to understanding the structure and function of neuronal circuits. Here, we have developed a simple, affordable strategy for labeling of genetically defined populations of neurons throughout a targeted brain region: Bulk Regional Viral Injection (BReVI). Our strategy involves a large volume adeno-associated virus (AAV) injection in the targeted brain region of neonatal Cre driver mice. Using the mouse olfactory bulb (OB) as a model system, we tested the ability of BReVI to broadly and selectively label tufted cells, one of the two principal neuron populations of the OB, in CCK-IRES-Cre mice. BReVI resulted in labeling of neurons throughout the injected OB, with no spatial bias toward the injection site and no evidence of damage. The specificity of BReVI labeling was strikingly similar to that seen previously using immunohistochemical staining for cholecystokinin (CCK), an established tufted cell marker. Hence, the CCK-IRES-Cre line in combination with BReVI can provide an important tool for targeting and manipulation of OB tufted cells. We also found robust Cre-dependent reporter expression within three days of BReVI, which enabled us to assess developmental changes in the number and laminar distribution of OB tufted cells during the first three postnatal weeks. Furthermore, we demonstrate that BReVI permits structural and functional imaging in vivo, and can be combined with transgenic strategies to facilitate multi-color labeling of neuronal circuit components. BReVI is broadly applicable to different Cre driver lines and can be used to regionally manipulate genetically defined populations of neurons in any accessible brain region. PMID:26594154

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Urinary schistosomiasis in southern Ghana: 1. Prevalence and morbidity assessment in three (defined) rural areas drained by the Densu river.

    PubMed

    Aryeetey, M E; Wagatsuma, Y; Yeboah, G; Asante, M; Mensah, G; Nkrumah, F K; Kojima, S

    2000-08-01

    Epidemiological studies on urinary schistosomiasis were carried out in eight villages in the Ga and Akuapem South districts in Ghana. Single urine samples were collected from individuals aged 5 years and above between 10.00 and 14.00 h. The samples were examined for the presence of Schistosoma haematobium eggs using a filtration technique. Indirect morbidity was determined as the presence of microhaematuria and proteinuria using reagent strips, and macrohaematuria was recorded with the naked eye. Out of the study population of 3912 subjects, 2562 (65.5%) submitted urine samples. The prevalence of a Schistosoma haematobium infection ranged between 54.8 and 60.0%. Infection rates increased by age with a peak in the 10-19 years category, and decreased with increasing age. Disease prevalence was higher in males aged 15 years and above in Areas 2 (Ntoaso and Sansami Amanfro) and 3 (Dom Faase, Papase, Chento and Gidi Kope), whereas it was higher among males aged 10 years and above in Area 1 (Ayikai Doblo and Akramaman). The intensity of infection was highest among children aged 10-14 years in most of the villages. More than half of egg-positive children in this age group had a heavy infection (100 eggs and above in 10 ml of urine). Although both egg-positive and egg-negative individuals manifested variable degrees of macro- or micro-haematuria, microhaematuria was more prevalent among egg-positives (chi(2)=918.5, d.f.=1, P<0.01). The degree of microhaematuria and proteinuria were significantly associated with the intensity of the infection. These results indicate a high transmission of disease in the study area. PMID:10882905

  3. Carpal Tunnel Syndrome Assessment with Ultrasonography: Value of Inlet-to-Outlet Median Nerve Area Ratio in Patients versus Healthy Volunteers

    PubMed Central

    Liu, Fang; Zhu, Jiaan; Ye, Dongmei; Feng, Xianxuan; Xu, Yiming; Wang, Gang; Bai, Yuehong

    2015-01-01

    Objective To evaluate the diagnostic value of the Inlet-to-outlet median nerve area ratio (IOR) in patients with clinically and electrophysiologically confirmed carpal tunnel syndrome (CTS). Methods Forty-six wrists in 46 consecutive patients with clinical and electrodiagnostic evidence of CTS and forty-four wrists in 44 healthy volunteers were examined with ultrasonography. The cross-sectional area (CSA) of the median nerve was measured at the carpal tunnel inlet (the level of scaphoid-pisiform) and outlet (the level of the hook of the hamate), and the IOR was calculated for each wrist. Ultrasonography and electrodiagnostic tests were performed under blinded conditions. Electrodiagnostic testing combined with clinical symptoms were considered to be the gold standard test. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic value between the inlet CSA and IOR. Results The study population included 16 men and 30 women (mean age, 45.3 years; range, 18–83 years). The control population included 18 men and 26 women (mean age, 50.4 years; range, 18–79 years). The mean inlet CSA was 8.7 mm2 in healthy controls and 14.6mm2 in CTS group (P<0.001). The mean IOR in healthy volunteers (1.0) was smaller than that in patients (1.6, P<0.001). Receiver operating characteristic analysis revealed a diagnostic advantage to using the IOR rather than the inlet CSA (P<0.01). An IOR cutoff value of ≥ 1.3 would yield 93% specificity and 91% sensitivity in the diagnosis of CTS. Conclusion The IOR of median nerve area promises to be an effective means in the diagnosis of CTS. A large-scale, randomized controlled trial is required to determine how and when this parameter will be used. PMID:25617835

  4. Digital soil mapping for the support of delineation of Areas Facing Natural Constraints defined by common European biophysical criteria

    NASA Astrophysics Data System (ADS)

    Pásztor, László; Bakacsi, Zsófia; Laborczi, Annamária; Takács, Katalin; Szatmári, Gábor; Tóth, Tibor; Szabó, József

    2016-04-01

    One of the main objectives of the EU's Common Agricultural Policy is to encourage maintaining agricultural production in Areas Facing Natural Constraints (ANC) in order to sustain agricultural production and use natural resources, in such a way to secure both stable production and income to farmers and to protect the environment. ANC assignment has both ecological and severe economical aspects. Recently the delimitation of ANCs is suggested to be carried out by using common biophysical diagnostic criteria on low soil productivity and poor climate conditions all over Europe. The criterion system was elaborated and has been repeatedly upgraded by JRC. The operational implementation is under member state competence. This process requires application of available soil databases and proper thematic and spatial inference methods. In our paper we present the inferences applied for the latest identification and delineation of areas with low soil productivity in Hungary according to JRC biophysical criteria related to soil: limited soil drainage, texture and stoniness (coarse texture, heavy clay, vertic properties), shallow rooting depth, chemical properties (salinity, sodicity, low pH). The compilation of target specific maps were based on the available legacy and recently collected data. In the present work three different data sources were used. The most relevant available data were queried from the datasets for each mapped criterion for either direct application or for the compilation a suitable, synthetic (non-measured) parameter. In some cases the values of the target variable originated from only one, in other cases from more databases. The reference dataset used in the mapping process was set up after substantial statistical analysis and filtering. It consisted of the values of the target variable attributed to the finally selected georeferenced locations. For spatial inference regression kriging was applied. Accuracy assessment was carried out by Leave One Out

  5. The decrease of β-synuclein in cortical brain areas defines a molecular subgroup of dementia with Lewy bodies.

    PubMed

    Beyer, Katrin; Domingo-Sàbat, Montserrat; Santos, Cristina; Tolosa, Eduardo; Ferrer, Isidro; Ariza, Aurelio

    2010-12-01

    Lewy body diseases include dementia with Lewy bodies and Parkinson's disease. Whereas dementia with Lewy bodies and Parkinson's disease can be distinguished as separate clinical entities, the pathological picture is very often identical. α-synuclein aggregation is a key event in the pathogenesis of Lewy body diseases and β-synuclein inhibits α-synuclein aggregation in vitro and in vivo. Recently, β-synuclein has been shown to interact directly with α-synuclein, regulating its functionality and preventing its oligomerization. In this study, we analysed the expression of two β-synuclein transcript variants and the main α-synuclein transcript SNCA140, in frozen samples of three areas from brains of patients with (i) pure diffuse Lewy body pathology; (ii) pure Alzheimer's disease pathology; (iii) diffuse Lewy body pathology and concomitant Alzheimer's disease pathology and (iv) controls. Relative messenger RNA expression was determined by real-time polymerase chain reaction, expression changes were evaluated by the ΔΔC(t) method and messenger RNA expression data were confirmed at the protein level. A drastic diminution of β-synuclein expression was observed in cortical areas of all samples that presented neuropathological features corresponding to pure diffuse Lewy body pathology and the clinical phenotype of dementia with Lewy bodies, but not in those with neuropathological features corresponding to diffuse Lewy body pathology and concomitant Alzheimer's disease pathology or the clinical phenotype of Parkinson's disease with dementia. The correlation of expression data with the clinical phenotype and neuropathological diagnosis of the patients suggested the existence of a specific molecular subtype of dementia with Lewy bodies, characterized by a strong decrease of β-synuclein in the frontal and temporal cortices. Furthermore, our findings provide new insights into the pathogenesis of Lewy body diseases that may be important for the understanding of

  6. Volume and surface area of a spherical harmonic surface approximation to a NIF implosion core defined by HGXI/GXD images from the equator and pole

    SciTech Connect

    Koch, J A

    2011-10-26

    A solid object, such as a simplified approximation to an implosion core defined by the 17% intensity contour, can be described by a sum of spherical harmonics, following the notation of Butkov (Mathematical Physics, ISBN 0-201-00727-4, 1968; there are other notations so care is required), with Pl(x) being the usual (apparently standard) Legendre polynomial. For the present purposes, finding the volume and surface area of an implosion core defined by P0, P2, P4, M0, and M4, I will restrict the problem to consider only A{sub 00}, A{sub 20}, A{sub 40}, and A{sub 44}, with the phase angle set to eliminate the sin(m{phi}) term. Once the volume and surface area are determined, I will explore how these coefficients relate to measured quantities A0, A2/A0, A4/A0, M0, and M4/M0.

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

    PubMed

    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

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

    PubMed Central

    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

  9. Physiological Intracellular Crowdedness is Defined by the Perimeter-to-Area Ratio of Sub-Cellular Compartments

    PubMed Central

    Hiroi, Noriko; Okuhara, Takahiro; Kubojima, Takeshi; Iba, Keisuke; Tabira, Akito; Yamashita, Shuji; Okada, Yasunori; Kobayashi, Tetsuya J.; Funahashi, Akira

    2012-01-01

    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. PMID:22936917

  10. Design and fabrication of a perpendicular magnetic tunnel junction based nonvolatile programmable switch achieving 40% less area using shared-control transistor structure

    NASA Astrophysics Data System (ADS)

    Suzuki, D.; Natsui, M.; Mochizuki, A.; Miura, S.; Honjo, H.; Kinoshita, K.; Fukami, S.; Sato, H.; Ikeda, S.; Endoh, T.; Ohno, H.; Hanyu, T.

    2014-05-01

    A compact nonvolatile programmable switch (NVPS) using 90 nm CMOS technology together with perpendicular magnetic tunnel junction (p-MTJ) devices is fabricated for zero-standby-power field-programmable gate array. Because routing information does not change once it is programmed into an NVPS, high-speed read and write accesses are not required and a write-control transistor can be shared among all the NVPSs, which greatly simplifies structure of the NVPS. In fact, the effective area of the proposed NVPS is reduced by 40% compared to that of a conventional MTJ-based NVPS. The instant on/off behavior without external nonvolatile memory access is also demonstrated using the fabricated test chip.

  11. On-road emissions of carbonyls from vehicles powered by biofuel blends in traffic tunnels in the Metropolitan Area of Sao Paulo, Brazil

    NASA Astrophysics Data System (ADS)

    Nogueira, Thiago; Souza, Kely Ferreira de; Fornaro, Adalgiza; Andrade, Maria de Fatima; Carvalho, Lilian Rothschild Franco de

    2015-05-01

    On-road emissions of carbonyls from the current vehicle fleet of Brazil were determined in two experimental campaigns, conducted in traffic tunnels located in the Metropolitan Area of São Paulo (MASP), in southeastern Brazil. Among carbonyl species, formaldehyde and acetaldehyde were the most abundant in all sampling periods. In Brazil, heavy-duty vehicles (HDVs) run on a blend of 95% regular diesel/5% biodiesel from soy, whereas light-duty vehicles (LDVs) run on gasohol (75-80% gasoline/20-25% ethanol) or hydrous ethanol. We found that HDVs showed the highest overall carbonyl emissions, although LDVs were responsible for high emissions of acetaldehyde. In comparison with LDVs in California, which are powered by 90% gasoline/10% ethanol, LDVs in Brazil were found to emit 352% and 263% more formaldehyde and acetaldehyde.

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

    SciTech Connect

    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.

  13. A high surface area tunnel-type α-MnO2 nanorod cathode by a simple solvent-free synthesis for rechargeable aqueous zinc-ion batteries

    NASA Astrophysics Data System (ADS)

    Alfaruqi, Muhammad Hilmy; Islam, Saiful; Gim, Jihyeon; Song, Jinju; Kim, Sungjin; Pham, Duong Tung; Jo, Jeonggeun; Xiu, Zhiliang; Mathew, Vinod; Kim, Jaekook

    2016-04-01

    Tunnel-type α-MnO2 with a nanorod morphology was prepared via a simple solvent-free synthesis method for use in aqueous zinc-ion battery (ZIB). This synthesis method produced α-MnO2 with a high BET surface area of 153 m2 g-1. α-MnO2 electrode demonstrated remarkable zinc storage properties (first and second discharge capacities of 323 and 270 mAh g-1 at 16 mA g-1) with good capacity retentions and rate capability. After charging within only 60 s, the α-MnO2 nanorod cathode delivered a considerable discharge capacity of 115 mAh g-1 when cycled at current density of 16 mA g-1.

  14. Virtual-detector approach to tunnel ionization and tunneling times

    NASA Astrophysics Data System (ADS)

    Teeny, Nicolas; Keitel, Christoph H.; Bauke, Heiko

    2016-08-01

    Tunneling times in atomic ionization are studied theoretically by a virtual detector approach. A virtual detector is a hypothetical device that allows one to monitor the wave function's density with spatial and temporal resolution during the ionization process. With this theoretical approach, it becomes possible to define unique moments when the electron enters and leaves with highest probability the classically forbidden region from first principles and a tunneling time can be specified unambiguously. It is shown that neither the moment when the electron enters the tunneling barrier nor when it leaves the tunneling barrier coincides with the moment when the external electric field reaches its maximum. Under the tunneling barrier as well as at the exit the electron has a nonzero velocity in the electric field direction. This nonzero exit velocity has to be incorporated when the free motion of the electron is modeled by classical equations of motion.

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

    PubMed

    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.

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

    PubMed

    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. PMID:27053177

  17. Tunneling time, what is its meaning?

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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.

  18. Quiet wind tunnel

    NASA Technical Reports Server (NTRS)

    Howard, P. W.; Schutzenhofer, L. A.

    1978-01-01

    Simple and inexpensive technique suppresses background noise generated by pores in wind tunnel wall lining and makes aerodynamic data more accurate and reliable. Porous walls are covered with wire-mesh screen. Screen offers smoother surface to airflow and damps vortexes and resonance caused by wall perforations; yet it provides enough open area for perforations to cancel shock waves generated by model.

  19. PREFACE: Time-resolved scanning tunnelling microscopy Time-resolved scanning tunnelling microscopy

    NASA Astrophysics Data System (ADS)

    Zandvliet, Harold J. W.; Lin, Nian

    2010-07-01

    out the potential landscape of the system (often a molecule or an atom) under study [4, 5]. However, the dynamical processes might also be induced by the tunnelling process itself [6, 7]. In the field of molecular science, excited single molecule experiments have been especially performed [8]. As a nice example, we refer to the work of Sykes' group [9] on thioether molecular rotors. In addition, several groups explore the possibility of combining time-resolved scanning tunnelling microscopy with optical techniques [10, 11]. Although the majority of studies that have been performed so far focus on rather simple systems under nearly ideal and well-defined conditions, we anticipate that time-resolved scanning tunnelling microscopy can also be applied in other research areas, such as biology and soft condensed matter, where the experimental conditions are often less ideal. We hope that readers will enjoy this collection of papers and that it will trigger them to further explore the possibilities of this simple, but powerful technique. References [1] Besenbacher F, Laegsgaard E and Stengaard I 2005 Mater. Today 8 26 [2] van Houselt A and Zandvliet H J W 2010 Rev. Mod. Phys. 82 1593 [3] Tringides M C and Hupalo M 2010 J. Phys.: Condens. Matter 22 264002 [4] Ronci F, Colonna S, Cricenti A and Le Lay G 2010 J. Phys.: Condens. Matter 22 264003 [5] van Houselt A, Poelsema B and Zandvliet H J W 2010 J. Phys.: Condens. Matter 22 264004 [6] Sprodowski C, Mehlhorn M and Morgenstern K 2010 J. Phys.: Condens. Matter 22 264005 [7] Saedi A, Poelsema B and Zandvliet H J W 2010 J. Phys.: Condens. Matter 22 264007 [8] Sloan P A 2010 J. Phys.: Condens. Matter 22 264001 [9] Jewell A D, Tierney H L, Baber A E, Iski E V, Laha M M and Sykes E C H 2010 J. Phys.: Condens. Matter 22 264006 [10] Riedel D 2010 J. Phys.: Condens. Matter 22 264009 [11] Terada Y, Yoshida S, Takeuchi O and Shigekawa H 2010 J. Phys.: Condens. Matter 22 264008

  20. Geochemical and hydrologic characterization of the effluent draining from U12e, U12n, and U12t tunnels, area 12, Nevada Test Site

    SciTech Connect

    Russell, C.E.; Gillespie, L.; Gillespie, D.

    1993-05-01

    The objective of the Tunnel Effluent Characterization Project at the Nevada Test Site was to characterize the tunnel effluents in terms of rate of discharge, pH, temperature, specific conductivity, turbidity, and aqueous chemistry. The parameters were monitored for one year to identify hazardous constituents within the effluent and to characterize temporal variations.

  1. Quantitative risk assessment modeling for nonhomogeneous urban road tunnels.

    PubMed

    Meng, Qiang; Qu, Xiaobo; Wang, Xinchang; Yuanita, Vivi; Wong, Siew Chee

    2011-03-01

    Urban road tunnels provide an increasingly cost-effective engineering solution, especially in compact cities like Singapore. For some urban road tunnels, tunnel characteristics such as tunnel configurations, geometries, provisions of tunnel electrical and mechanical systems, traffic volumes, etc. may vary from one section to another. These urban road tunnels that have characterized nonuniform parameters are referred to as nonhomogeneous urban road tunnels. In this study, a novel quantitative risk assessment (QRA) model is proposed for nonhomogeneous urban road tunnels because the existing QRA models for road tunnels are inapplicable to assess the risks in these road tunnels. This model uses a tunnel segmentation principle whereby a nonhomogeneous urban road tunnel is divided into various homogenous sections. Individual risk for road tunnel sections as well as the integrated risk indices for the entire road tunnel is defined. The article then proceeds to develop a new QRA model for each of the homogeneous sections. Compared to the existing QRA models for road tunnels, this section-based model incorporates one additional top event-toxic gases due to traffic congestion-and employs the Poisson regression method to estimate the vehicle accident frequencies of tunnel sections. This article further illustrates an aggregated QRA model for nonhomogeneous urban tunnels by integrating the section-based QRA models. Finally, a case study in Singapore is carried out.

  2. Tunnel electroresistance through organic ferroelectrics

    PubMed Central

    Tian, B. B.; Wang, J. L.; Fusil, S.; Liu, Y.; Zhao, X. L.; Sun, S.; Shen, H.; Lin, T.; Sun, J. L.; Duan, C. G.; Bibes, M.; Barthélémy, A.; Dkhil, B.; Garcia, V.; Meng, X. J.; Chu, J. H.

    2016-01-01

    Organic electronics is emerging for large-area applications such as photovoltaic cells, rollable displays or electronic paper. Its future development and integration will require a simple, low-power organic memory, that can be written, erased and readout electrically. Here we demonstrate a non-volatile memory in which the ferroelectric polarisation state of an organic tunnel barrier encodes the stored information and sets the readout tunnel current. We use high-sensitivity piezoresponse force microscopy to show that films as thin as one or two layers of ferroelectric poly(vinylidene fluoride) remain switchable with low voltages. Submicron junctions based on these films display tunnel electroresistance reaching 1,000% at room temperature that is driven by ferroelectric switching and explained by electrostatic effects in a direct tunnelling regime. Our findings provide a path to develop low-cost, large-scale arrays of organic ferroelectric tunnel junctions on silicon or flexible substrates. PMID:27143121

  3. Tunnel electroresistance through organic ferroelectrics

    NASA Astrophysics Data System (ADS)

    Tian, B. B.; Wang, J. L.; Fusil, S.; Liu, Y.; Zhao, X. L.; Sun, S.; Shen, H.; Lin, T.; Sun, J. L.; Duan, C. G.; Bibes, M.; Barthélémy, A.; Dkhil, B.; Garcia, V.; Meng, X. J.; Chu, J. H.

    2016-05-01

    Organic electronics is emerging for large-area applications such as photovoltaic cells, rollable displays or electronic paper. Its future development and integration will require a simple, low-power organic memory, that can be written, erased and readout electrically. Here we demonstrate a non-volatile memory in which the ferroelectric polarisation state of an organic tunnel barrier encodes the stored information and sets the readout tunnel current. We use high-sensitivity piezoresponse force microscopy to show that films as thin as one or two layers of ferroelectric poly(vinylidene fluoride) remain switchable with low voltages. Submicron junctions based on these films display tunnel electroresistance reaching 1,000% at room temperature that is driven by ferroelectric switching and explained by electrostatic effects in a direct tunnelling regime. Our findings provide a path to develop low-cost, large-scale arrays of organic ferroelectric tunnel junctions on silicon or flexible substrates.

  4. Tunnel electroresistance through organic ferroelectrics.

    PubMed

    Tian, B B; Wang, J L; Fusil, S; Liu, Y; Zhao, X L; Sun, S; Shen, H; Lin, T; Sun, J L; Duan, C G; Bibes, M; Barthélémy, A; Dkhil, B; Garcia, V; Meng, X J; Chu, J H

    2016-01-01

    Organic electronics is emerging for large-area applications such as photovoltaic cells, rollable displays or electronic paper. Its future development and integration will require a simple, low-power organic memory, that can be written, erased and readout electrically. Here we demonstrate a non-volatile memory in which the ferroelectric polarisation state of an organic tunnel barrier encodes the stored information and sets the readout tunnel current. We use high-sensitivity piezoresponse force microscopy to show that films as thin as one or two layers of ferroelectric poly(vinylidene fluoride) remain switchable with low voltages. Submicron junctions based on these films display tunnel electroresistance reaching 1,000% at room temperature that is driven by ferroelectric switching and explained by electrostatic effects in a direct tunnelling regime. Our findings provide a path to develop low-cost, large-scale arrays of organic ferroelectric tunnel junctions on silicon or flexible substrates. PMID:27143121

  5. Edge geometry superconducting tunnel junctions utilizing an NbN/MgO/NbN thin film structure

    NASA Technical Reports Server (NTRS)

    Hunt, Brian D. (Inventor); Leduc, Henry G. (Inventor)

    1992-01-01

    An edge defined geometry is used to produce very small area tunnel junctions in a structure with niobium nitride superconducting electrodes and a magnesium oxide tunnel barrier. The incorporation of an MgO tunnel barrier with two NbN electrodes results in improved current-voltage characteristics, and may lead to better junction noise characteristics. The NbN electrodes are preferably sputter-deposited, with the first NbN electrode deposited on an insulating substrate maintained at about 250 C to 500 C for improved quality of the electrode.

  6. Sourcebook of locations of geophysical surveys in tunnels and horizontal holes including results of seismic-refraction surveys: Rainier Mesa, Aqueduct Mesa, and Area 16, Nevada Test Site

    SciTech Connect

    Carroll, R.D.; Kibler, J.E.

    1983-01-01

    Seismic refraction surveys have been obtained sporadically in tunnels in zeolitized tuff at the Nevada Test Site since the late 1950's. Commencing in 1967 and continuing to date (1982), extensive measurements of shear- and compressional-wave velocities have been made in five tunnel complexes in Rainier and Aqueduct Mesas and in one tunnel complex in Shoshone Mountain. The results of these surveys to 1980 are compiled in this report. In addition, extensive horizontal drilling was initiated in 1967 in connection with geologic exploration in these tunnel complexes for sites for nuclear weapons tests. Seismic and electrical surveys were conducted in the majority of these holes. The type and location of these tunnel and borehole surveys are indexed in this report. Synthesis of the seismic refraction data indicates a mean compressional-wave velocity near the nuclear device point (WP) of 23 tunnel events of 2430 m/s (7970 f/s) with a range of 1846 to 2753 m/s (6060 to 9030 f/s). The mean shear-wave velocity of 17 tunnel events is 1276 m/s (4190 f/s) with a range of 1140 to 1392 m/s (3740 to 4570 f/s). Experience indicates that these velocity variations are due chiefly to the extent of fracturing and (or) the presence of partially saturated rock in the region of the survey.

  7. Sourcebook of locations of geophysical surveys in tunnels and horizontal holes, including results of seismic refraction surveys, Rainier Mesa, Aqueduct Mesa, and Area 16, Nevada Test Site

    USGS Publications Warehouse

    Carroll, R.D.; Kibler, J.E.

    1983-01-01

    Seismic refraction surveys have been obtained sporadically in tunnels in zeolitized tuff at the Nevada Test Site since the late 1950's. Commencing in 1967 and continuing to date (1982), .extensive measurements of shear- and compressional-wave velocities have been made in five tunnel complexes in Rainier and Aqueduct Mesas and in one tunnel complex in Shoshone Mountain. The results of these surveys to 1980 are compiled in this report. In addition, extensive horizontal drilling was initiated in 1967 in connection with geologic exploration in these tunnel complexes for sites for nuclear weapons tests. Seismic and electrical surveys were conducted in the majority of these holes. The type and location of these tunnel and borehole surveys are indexed in this report. Synthesis of the seismic refraction data indicates a mean compressional-wave velocity near the nuclear device point (WP) of 23 tunnel events of 2,430 m/s (7,970 f/s) with a range of 1,846-2,753 m/s (6,060-9,030 f/s). The mean shear-wave velocity of 17 tunnel events is 1,276 m/s (4,190 f/s) with a range of 1,140-1,392 m/s (3,740-4,570 f/s). Experience indicates that these velocity variations are due chiefly to the extent of fracturing and (or) the presence of partially saturated rock in the region of the survey.

  8. Defining "Development".

    PubMed

    Pradeu, Thomas; Laplane, Lucie; Prévot, Karine; Hoquet, Thierry; Reynaud, Valentine; Fusco, Giuseppe; Minelli, Alessandro; Orgogozo, Virginie; Vervoort, Michel

    2016-01-01

    Is it possible, and in the first place is it even desirable, to define what "development" means and to determine the scope of the field called "developmental biology"? Though these questions appeared crucial for the founders of "developmental biology" in the 1950s, there seems to be no consensus today about the need to address them. Here, in a combined biological, philosophical, and historical approach, we ask whether it is possible and useful to define biological development, and, if such a definition is indeed possible and useful, which definition(s) can be considered as the most satisfactory.

  9. Vehicular emission factors and chemical profile of Particulate Matter measured in two road tunnels in the Metropolitan Area of Sao Paulo, Brazil

    NASA Astrophysics Data System (ADS)

    Nogueira, T.; Miranda, R. M.; Dominutti, P. A.; Hetem, I. G.; Fornaro, A.; Andrade, M.

    2013-12-01

    The main source of air pollution in the Metropolitan Area of São Paulo (MASP), Brazil, is vehicle exhaust. In this study, trace-element concentrations inside and outside of two traffic tunnels in the MASP are shown. The experiments were conducted in May and July 2011, respectively, in the Jânio Quadros (JQT) and Rodoanel (RAT) road tunnels, both located in MASP. The JQT carries mainly light-duty vehicles (LDV), whereas the RAT carries LDVs and heavy-duty vehicles (HDV). Hourly carbon dioxide, carbon monoxide, nitrogen oxides and sulfur dioxide were measured during the sampling campaign. Particulate matter (PM2.5 and PM2.5-10) samples were collected 6-h (daytime) and 12-h (overnight), employing gravimetric analysis to quantify PM mass concentration; reflectance to quantify black carbon (BC) concentrations and X-ray fluorescence to characterize elemental composition. Mean concentrations for PM2.5 and BC inside the JQT were 41(×11), and 19(×9) μg/m3, respectively. In the RAT mean concentrations were 175(×61), and 140(×78) μg/m3, for PM2.5 and BC, respectively. Emission Factors (EFs) for PM2.5, PM2.5-10, BC and trace metal (Na to Pb) from mobile sources operating under real-world conditions were determined using these traffic tunnels in the MASP as experimental set-up. LDV emission factors were 45 × 18 mg/km, 39 × 17 mg/km, 306 × 121 μg/km, 108 × 46 μg/km, 742 × 453 μg/km, 624 × 261 μg/km, and 33 × 15 μg/km, for PM2.5, BC, Na, P, S, Cu, and Pb, respectively. HDV emission factors were 326 × 119 mg/km, 231 × 98 mg/km, 446 × 218 μg/km, 384 × 143 μg/km, 4618 × 1878 μg/km, 44 × 18 μg/km, and 46 × 20 μg/km, for PM2.5, BC, Na, P, S, Cu, and Pb, respectively. In general, the mean contribution of HDVs to the emissions of fine particles was from 1.4 to 7.3 times higher than that of LDVs. In addition, the data show a significant reduction in the EFs values when compared with data obtained in the last campaign held in the MASP in 2004. The reduction

  10. Defining Infertility

    MedlinePlus

    ... of the American Society for Reproductive Medicine Defining infertility What is infertility? Infertility is “the inability to conceive after 12 months ... to conceive after 6 months is generally considered infertility. How common is it? Infertility affects 10%-15% ...

  11. Defining chaos

    SciTech Connect

    Hunt, Brian R.; Ott, Edward

    2015-09-15

    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.

  12. Pressure-morphology relationship of a released carpal tunnel.

    PubMed

    Kim, Dong Hee; Marquardt, Tamara L; Gabra, Joseph N; Shen, Zhilei Liu; Evans, Peter J; Seitz, William H; Li, Zong-Ming

    2013-04-01

    We investigated morphological changes of a released carpal tunnel in response to variations of carpal tunnel pressure. Pressure within the carpal tunnel is known to be elevated in patients with carpal tunnel syndrome and dependent on wrist posture. Previously, increased carpal tunnel pressure was shown to affect the morphology of the carpal tunnel with an intact transverse carpal ligament (TCL). However, the pressure-morphology relationship of the carpal tunnel after release of the TCL has not been investigated. Carpal tunnel release (CTR) was performed endoscopically on cadaveric hands and the carpal tunnel pressure was dynamically increased from 10 to 120 mmHg. Simultaneously, carpal tunnel cross-sectional images were captured by an ultrasound system, and pressure measurements were recorded by a pressure transducer. Carpal tunnel pressure significantly affected carpal arch area (p < 0.001), with an increase of >62 mm(2) at 120 mmHg. Carpal arch height, length, and width also significantly changed with carpal tunnel pressure (p < 0.05). As carpal tunnel pressure increased, carpal arch height and length increased, but the carpal arch width decreased. Analyses of the pressure-morphology relationship for a released carpal tunnel revealed a nine times greater compliance than that previously reported for a carpal tunnel with an intact TCL. This change of structural properties as a result of transecting the TCL helps explain the reduction of carpal tunnel pressure and relief of symptoms for patients after CTR surgery.

  13. National Wind Tunnel Complex (NWTC)

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The National Wind Tunnel Complex (NWTC) Final Report summarizes the work carried out by a unique Government/Industry partnership during the period of June 1994 through May 1996. The objective of this partnership was to plan, design, build and activate 'world class' wind tunnel facilities for the development of future-generation commercial and military aircraft. The basis of this effort was a set of performance goals defined by the National Facilities Study (NFS) Task Group on Aeronautical Research and Development Facilities which established two critical measures of improved wind tunnel performance; namely, higher Reynolds number capability and greater productivity. Initial activities focused upon two high-performance tunnels (low-speed and transonic). This effort was later descoped to a single multipurpose tunnel. Beginning in June 1994, the NWTC Project Office defined specific performance requirements, planned site evaluation activities, performed a series of technical/cost trade studies, and completed preliminary engineering to support a proposed conceptual design. Due to budget uncertainties within the Federal government, the NWTC project office was directed to conduct an orderly closure following the Systems Design Review in March 1996. This report provides a top-level status of the project at that time. Additional details of all work performed have been archived and are available for future reference.

  14. 6. VIEW OF FIVEFOOT WIND TUNNEL WITH AIR STRAIGHTENER AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW OF FIVE-FOOT WIND TUNNEL WITH AIR STRAIGHTENER AND OPERATOR STATION IN FOREGROUND (1991). - Wright-Patterson Air Force Base, Area B, Building No. 19, Five-Foot Wind Tunnel, Dayton, Montgomery County, OH

  15. Looking into Tunnel Books.

    ERIC Educational Resources Information Center

    Hinshaw, Craig

    1999-01-01

    Describes how to make tunnel books, which are viewed by looking into a "tunnel" created by accordion-folded expanding sides. Suggests possible themes. Describes how to create a walk-through tunnel book for first grade students. (CMK)

  16. Carpal Tunnel Syndrome

    MedlinePlus

    ... arm. Just a passing cramp? It could be carpal tunnel syndrome. The carpal tunnel is a narrow passageway of ligament and ... difficult. Often, the cause is having a smaller carpal tunnel than other people do. Other causes include ...

  17. Unitary Plan Supersonic Tunnel

    NASA Technical Reports Server (NTRS)

    1953-01-01

    Unitary Plan Supersonic Tunnel: In this aerial photograph of construction in the early 1950s, the return air passages are shown in the rear, center. This area was later covered with walls and a roof so that upon completion of the facility, it was not visible from the exterior. Three air storage spheres and the cooling tower are at the extreme right of the building. The spheres store dry air at 150 pounds per square inch. The cooling tower dissipates heat from coolers that control the test air temperature. One of many research facilities at NASA Langley Research Center in Hampton, Virginia, the Unitary Plan Wind Tunnel is used for experimental investigations at supersonic speeds.

  18. Retrofitting tunnel kilns

    SciTech Connect

    Lukacs, J.J.

    1997-02-01

    Significant benefits can be achieved by retrofitting tunnel kilns. The decision-making process to do so starts with evaluating short- and long-term goals. Plant goals can influence tradeoffs in burner sizing, burner choice and control scheme. The evaluation includes consideration of increased production, reduced breakage during heating and cooling, improved quality, ability to quickly change products, reduced fuel use, reduced energy consumption and/or improved control. The efforts in one area affect performance in other areas. For example, reduced fuel use implies reduced energy consumption. Regardless of the priority of the goals, the first step is an evaluation of the existing burners.

  19. Feasibility assessment of a tunnel-ventilated, water-padded barn on alleviation of heat stress for lactating Holstein cows in a humid area.

    PubMed

    Shiao, T F; Chen, J C; Yang, D W; Lee, S N; Lee, C F; Cheng, W T K

    2011-11-01

    The use of evaporative cooling for mitigating heat stress in lactating cows in humid areas is controversial. In Taiwan, Holstein cow performance is significantly restricted by hot and humid weather. This study investigated the efficacy of using a tunnel-ventilated, water-padded freestall (TP) barn for reducing heat stress in lactating cows. From August to October 2006, 36 cows allocated in a 3×3 Latin square were raised in 3 barn cooling treatments: a conventional freestall barn with fans and sprinklers in the feed line (Fan+SP, control), a TP barn, and a TP barn with sprinkler cooling (TP+SP). Daytime air speeds in the 3 barns were 1.23, 2.38, and 2.06 m/s, respectively. Both TP barns were more efficient than the control in reducing the daytime temperature and temperature-humidity index. The barn temperature was <26°C for an extra 4.2h per day, but the relative humidity was >96% in both TP barns. Cows in both TP barns had higher respiration rates and skin temperatures at 0300 h than cows in the Fan+SP barn. The TP environment increased the cows' serum cholesterol level and the activities of alkaline phosphatase and alanine aminotransferase, but blood partial pressure of CO(2) was not affected. Vaginal temperature was persistently high in cows in the TP barn; in the 2 SP barns, it decreased 0.4 to 0.6°C following sprinkling and milking. The intake activity and rumen digestion of cows raised in the 3 environments were similar. Cows in both TP barns ingested more dry matter. Cows in the TP+SP barn tended to produce more milk than those in the Fan+SP barn (25.4 vs. 24.7 kg). Although heat stress was not completely alleviated in these 3 barns, the TP+SP treatment resolved the negative effect of a previous TP barn built in 2004 on intake and milk yield by increasing air speed and using sprinkler cooling. Thus, it is expected that TP+SP barns will be beneficial in regions with high humidity. Adequate air speed and sprinkler cooling are likely to be key factors for

  20. Quantum temporal probabilities in tunneling systems

    SciTech Connect

    Anastopoulos, Charis Savvidou, Ntina

    2013-09-15

    We study the temporal aspects of quantum tunneling as manifested in time-of-arrival experiments in which the detected particle tunnels through a potential barrier. In particular, we present a general method for constructing temporal probabilities in tunneling systems that (i) defines ‘classical’ time observables for quantum systems and (ii) applies to relativistic particles interacting through quantum fields. We show that the relevant probabilities are defined in terms of specific correlation functions of the quantum field associated with tunneling particles. We construct a probability distribution with respect to the time of particle detection that contains all information about the temporal aspects of the tunneling process. In specific cases, this probability distribution leads to the definition of a delay time that, for parity-symmetric potentials, reduces to the phase time of Bohm and Wigner. We apply our results to piecewise constant potentials, by deriving the appropriate junction conditions on the points of discontinuity. For the double square potential, in particular, we demonstrate the existence of (at least) two physically relevant time parameters, the delay time and a decay rate that describes the escape of particles trapped in the inter-barrier region. Finally, we propose a resolution to the paradox of apparent superluminal velocities for tunneling particles. We demonstrate that the idea of faster-than-light speeds in tunneling follows from an inadmissible use of classical reasoning in the description of quantum systems. -- Highlights: •Present a general methodology for deriving temporal probabilities in tunneling systems. •Treatment applies to relativistic particles interacting through quantum fields. •Derive a new expression for tunneling time. •Identify new time parameters relevant to tunneling. •Propose a resolution of the superluminality paradox in tunneling.

  1. Tunneling nanotubes

    PubMed Central

    Austefjord, Magnus Wiger; Gerdes, Hans-Hermann; Wang, Xiang

    2014-01-01

    Tunneling nanotubes (TNTs) are recently discovered thin membranous tubes that interconnect cells. During the last decade, research has shown TNTs to be diverse in morphology and composition, varying between and within cell systems. In addition, the discovery of TNT-like extracellular protrusions, as well as observations of TNTs in vivo, has further enriched our knowledge on the diversity of TNT-like structures. Considering the complex molecular mechanisms underlying the formation of TNTs, as well as their different functions in intercellular communication, it is important to decipher how heterogeneity of TNTs is established, and to address what roles the compositional elements have in the execution of various functions. Here, we review the current knowledge on the morphological and structural diversity of TNTs, and address the relation between the formation, the structure, and the function of TNTs. PMID:24778759

  2. Improved multidimensional semiclassical tunneling theory.

    PubMed

    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. PMID:24224758

  3. Air quality inside a tunnel tube and in the vicinity of the tunnel portals

    SciTech Connect

    Pucher, K.; Zwiener, K.

    1997-12-31

    Due to the continually growing number of motor vehicles more and more roads are reaching the limits of their capability. This has led to slowly moving traffic and longer persisting traffic blockages. In cities and conurbation centers especially this leads to complete traffic chaos. The pollutant emissions of vehicles that only move very little mostly lead to high pollutant burdens also and in some circumstances to poor air quality. Therefore in more and more cities one is attempting to get traffic moving again through efficient road tunnels and underground lines and thereby also reduce the pollutant emission. Typical examples of such developments are the Central Artery Tunnel Project in Boston, the planned Ringroad tunnel in Stockholm and the Ringtunnel projects in Paris. Tunnel constructions and underground lines in densely built-up areas are also planned in many small cities. For all these tunnel projects the following points concerning the air quality are to be observed. On the one hand, a tunnel construction can accommodate traffic and thereby reduce the traffic blockages in the vicinity of the tunnel, so long as no additional traffic is attracted. This would therefore lead to a reduction of the pollutant burden and also to an improvement in the air quality in large areas of further surroundings of the tunnel construction. On the other hand, at the portals of the tunnel, alongside mobile pollutant sources from vehicles travelling on the already existing road, a stationary pollutant source of the tunnel ventilation flowing out from the tunnel portal also results. It is then to be investigated how high the emerging pollutant concentrations will be at the portal of the planned tunnel and how these pollutants will disseminate. In this report therefore, the air quality in the tunnel as well as in the vicinity of the tunnel portals will be more closely dealt with.

  4. Validation of the Lockheed Martin Morphing Concept with Wind Tunnel Testing

    NASA Technical Reports Server (NTRS)

    Ivanco, Thomas G.; Scott, Robert C.; Love, Michael H.; Zink Scott; Weisshaar, Terrence A.

    2007-01-01

    The Morphing Aircraft Structures (MAS) program is a Defense Advanced Research Projects Agency (DARPA) led effort to develop morphing flight vehicles capable of radical shape change in flight. Two performance parameters of interest are loiter time and dash speed as these define the persistence and responsiveness of an aircraft. The geometrical characteristics that optimize loiter time and dash speed require different geometrical planforms. Therefore, radical shape change, usually involving wing area and sweep, allows vehicle optimization across many flight regimes. The second phase of the MAS program consisted of wind tunnel tests conducted at the NASA Langley Transonic Dynamics Tunnel to demonstrate two morphing concepts and their enabling technologies with large-scale semi-span models. This paper will focus upon one of those wind tunnel tests that utilized a model developed by Lockheed Martin Aeronautics Company (LM). Wind tunnel success criteria were developed by NASA to support the DARPA program objectives. The primary focus of this paper will be the demonstration of the DARPA objectives by systematic evaluation of the wind tunnel model performance relative to the defined success criteria. This paper will also provide a description of the LM model and instrumentation, and document pertinent lessons learned. Finally, as part of the success criteria, aeroelastic characteristics of the LM derived MAS vehicle are also addressed. Evaluation of aeroelastic characteristics is the most detailed criterion investigated in this paper. While no aeroelastic instabilities were encountered as a direct result of the morphing design or components, several interesting and unexpected aeroelastic phenomenon arose during testing.

  5. The path decomposition expansion and multidimensional tunneling

    NASA Astrophysics Data System (ADS)

    Auerbach, Assa; Kivelson, S.

    This paper consists of two main topics. (i) The path decomposition expansion: a new path integral technique which allows us to break configuration space into disjoint regions and express the dynamics of the full system in terms of its parts. (ii) The application of the PDX and semiclassical methods for solving quantum-mechanical tunneling problems in multidimensions. The result is a conceptually simple, computationally straightforward method for calculating tunneling effects in complicated multidimensional potentials, even in cases where the nature of the states in the classically allowed regions is nontrivial. Algorithms for computing tunneling effects in general classes of problems are obtained.In addition, we present the detailed solutions to three model problems of a tunneling coordinate coupled to a phonon. This enables us to define various well-controlled approximation schemes, which help to reduce the dimensions of complicated tunneling calculations in real physical systems.

  6. The effect of developing a tunnel across a highway on the water quality in an upstream reservoir watershed area--a case study of the Hsuehshan tunnel in Taiwan.

    PubMed

    Shyu, Guey-Shin; Cheng, Bai-You; Fang, Wei-Ta

    2012-09-19

    Cities in Taiwan are so dependent on reservoir water that preservation of the upstream reservoir watershed has become a significant public concern. However, due to the high-density development of land, resulting in rapid urban expansion, the construction of tunnels and elevated highways across reservoirs to better utilize the surrounding land has become a global trend. Based on data from long-term observation of the reservoir, this study verifies the difference in water quality before and after the highway construction. The results indicate that the total phosphorus (TP) increased on average 14 μg/L to 36.5 μg/L per annum, and the water quality is expected to require 10 years to recover. During the highway development, the average TP was more than twice the normal level. During summer, the TP level increases 3.1-fold due to rainfall. As indicated by the results, the large-scale land development will harm the long-term preservation of the reservoir's water quality, and therefore should be avoided.

  7. On Defining Mass

    ERIC Educational Resources Information Center

    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…

  8. Defining Equality in Education

    ERIC Educational Resources Information Center

    Benson, Ronald E.

    1977-01-01

    Defines equality of education in three areas: 1) by the degree of integration of school systems; 2) by a comparison of material resources and assets in education; and 3) by the effects of schooling as measured by the mean scores of groups on standardized tests. Available from: College of Education, 107 Quadrangle, Iowa State University, Ames, Iowa…

  9. Quantum temporal probabilities in tunneling systems

    NASA Astrophysics Data System (ADS)

    Anastopoulos, Charis; Savvidou, Ntina

    2013-09-01

    We study the temporal aspects of quantum tunneling as manifested in time-of-arrival experiments in which the detected particle tunnels through a potential barrier. In particular, we present a general method for constructing temporal probabilities in tunneling systems that (i) defines 'classical' time observables for quantum systems and (ii) applies to relativistic particles interacting through quantum fields. We show that the relevant probabilities are defined in terms of specific correlation functions of the quantum field associated with tunneling particles. We construct a probability distribution with respect to the time of particle detection that contains all information about the temporal aspects of the tunneling process. In specific cases, this probability distribution leads to the definition of a delay time that, for parity-symmetric potentials, reduces to the phase time of Bohm and Wigner. We apply our results to piecewise constant potentials, by deriving the appropriate junction conditions on the points of discontinuity. For the double square potential, in particular, we demonstrate the existence of (at least) two physically relevant time parameters, the delay time and a decay rate that describes the escape of particles trapped in the inter-barrier region. Finally, we propose a resolution to the paradox of apparent superluminal velocities for tunneling particles. We demonstrate that the idea of faster-than-light speeds in tunneling follows from an inadmissible use of classical reasoning in the description of quantum systems.

  10. Tunnels Used in Community School Plan

    ERIC Educational Resources Information Center

    School Management, 1972

    1972-01-01

    In a Springfield, Massachusetts, school design, tunnels housing community facilities will make it possible to utilize otherwise unusable land and will create neighborhood ties in an area undergoing urban renewal. (Author)

  11. 4. 'Ring Stones & Tunnel Sections, Tunnel #33,' Southern Pacific ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. 'Ring Stones & Tunnel Sections, Tunnel #33,' Southern Pacific Standard Double-Track Tunnel, ca. 1913. Compare to photos in documentation sets for Tunnel 18 (HAER No. CA-197), Tunnel 34 (HAER No. CA-206), and Tunnel 1 (HAER No. CA-207). - Central Pacific Transcontinental Railroad, Sacramento to Nevada state line, Sacramento, Sacramento County, CA

  12. Variable-Density Tunnel

    NASA Technical Reports Server (NTRS)

    1921-01-01

    Wind Tunnel #2, building interior. Reinforced concrete foundation for Variable-Density Tunnel (VDT) under construction. The tank and contents weighed about 100 tons. Negative on roll #1 of copy negatives returned by National Archives on 70mm film rolls.

  13. Variable-Density Tunnel - Wind Tunnel #2

    NASA Technical Reports Server (NTRS)

    1923-01-01

    Underside of the Variable-Density Tunnel (VDT). The compressors are to the left. Balance detail - entrance view of wind tunnel #2. The photographer was probably shooting film for Dr. Joseph Ames' Wilbur Wright Memorial Lecture given to the Royal Aeronautical Society on May 31, 1923.

  14. The Tunnels of Samos

    NASA Technical Reports Server (NTRS)

    Apostol, Tom M. (Editor)

    1995-01-01

    This 'Project Mathematics' series video from CalTech presents the tunnel of Samos, a famous underground aquaduct tunnel located near the capital of Pithagorion (named after the famed Greek mathematician, Pythagoras, who lived there), on one of the Greek islands. This tunnel was constructed around 600 BC by King Samos and was built under a nearby mountain. Through film footage and computer animation, the mathematical principles and concepts of why and how this aquaduct tunnel was built are explained.

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

    SciTech Connect

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  17. Variable Density Tunnel

    NASA Technical Reports Server (NTRS)

    1931-01-01

    Variable Density Tunnel in operation. Man at far right is probably Harold J. 'Cannonball' Tuner, longtime safety officer, who started with Curtiss in the teens. This view of the Variable Density Tunnel clearly shows the layout of the Tunnel's surroundings, as well as the plumbing and power needs of the this innovative research tool.

  18. Exploration, Drilling and Development Operations in the Bottle Rock Area of the Geysers Steam Field, With New Geologic Insights and Models Defining Reservoir Parameters

    SciTech Connect

    Hebein, Jeffrey J.

    1983-12-15

    MCR Geothermal Corporation pioneered successful exploratiory drilling the Bottle Rock area of the Geysers Steam Field in 1976. The wellfield is characterized by a deep reservoir with varied flowrates, temperatures, pressures, and stem chemistries being quite acceptable. More detailed reservoir engineering tests will follow as production commences.

  19. Tunneling in Superconductors

    NASA Astrophysics Data System (ADS)

    Giaever, Ivar

    2002-03-01

    It has been said that Thomas Edison's greatest invention was that of the "Research Laboratory" as a social institution. My greatest discovery was when I learned at 29 years of age that it was possible to work in such an institution and get paid for doing research. I had become interested in physics, gotten a job at General Electric Research Laboratory and found a great mentor in John C. Fischer, who besides instructing me in physics told me that sooner or later we all would become historians of science. I guess for me that time is now, because I have been asked to tell you about my second greatest discovery: Tunneling in superconductors. My great fortune was to be at the right place at the right time, where I had access to outstanding and helpful (not necessary an oxymoron) physicists. Hopefully I will be able to convey to you some of the fun and excitement of that area in this recollection. If you become real interested you may find a written version in my Nobel Prize talk: "Electron Tunneling and Superconductivity" Les Prix Nobel en 1973 or Science 183, 1253-1258 1974 or Reviews of Modern Physics 46 (2), 245-250 1974

  20. Tertiary interactions within the ribosomal exit tunnel.

    PubMed

    Kosolapov, Andrey; Deutsch, Carol

    2009-04-01

    Although tertiary folding of whole protein domains is prohibited by the cramped dimensions of the ribosomal tunnel, dynamic tertiary interactions may permit folding of small elementary units within the tunnel. To probe this possibility, we used a beta-hairpin and an alpha-helical hairpin from the cytosolic N terminus of a voltage-gated potassium channel and determined a probability of folding for each at defined locations inside and outside the tunnel. Minimalist tertiary structures can form near the exit port of the tunnel, a region that provides an entropic window for initial exploration of local peptide conformations. Tertiary subdomains of the nascent peptide fold sequentially, but not independently, during translation. These studies offer an approach for diagnosing the molecular basis for folding defects that lead to protein malfunction and provide insight into the role of the ribosome during early potassium channel biogenesis.

  1. Tertiary Interactions within the Ribosomal Exit Tunnel

    PubMed Central

    Kosolapov, Andrey; Deutsch, Carol

    2009-01-01

    Although tertiary folding of whole protein domains is prohibited by the cramped dimensions of the ribosomal tunnel, dynamic tertiary interactions may permit folding of small elementary units within the tunnel. To probe this possibility, we used a β-hairpin as well as an α-helical hairpin from the cytosolic N-terminus of a voltage-gated potassium channel and determined a probability of folding for each at defined locations inside and outside the tunnel. Minimalist tertiary structures can form near the exit port of the tunnel, a region that provides an entropic window for initial exploration of local peptide conformations. Tertiary subdomains of the nascent peptide fold sequentially, but not independently, during translation. These studies offer an approach for diagnosing the molecular basis for folding defects that lead to protein malfunction and provide insight into the role of the ribosome during early potassium channel biogenesis. PMID:19270700

  2. Tunneling of a heavily damped macroscopic variable

    SciTech Connect

    Schwartz, D.B.

    1987-01-01

    The author studied the effect of damping upon fluxoid transitions in simple microfabricated circuits consisting of an inductor and small-area Josephson tunnel junctions. In order to provide an easily characterized source of damping, the tunnel junctions were fabricated with low-inductance resistive shunts across them. To keep tunneling from being suppressed to unreachably low temperatures, the samples were designed to exhibit tunneling at high temperatures in the absence of damping. This was achieved by having junction areas of approximately 0.1 ..mu../sup 2/, which pushes the characteristic time scales to over 10/sup 12/ s/sup -1/. Tunneling was unambiguously observed at 2K in the unshunted samples. The temperature where thermal activation won over tunneling in determining the escape rate was suppressed by an order of magnitude in the shunted samples, in good agreement with theoretical predictions. The predicted T/sup 2/ dependence of the exponent of the tunneling rate upon temperature was also clearly observed in the data. At temperatures where thermal activation dominates the escape-rate quantum corrections to the escape rate are predicted. Analysis of these effects upon the data is complicated by the high frequencies involved. Although the data does not constitute a clear test of these corrections, it seems clear that simple thermal activation without quantum corrections does not suffice to explain it.

  3. Fermion tunneling from dynamical horizons

    NASA Astrophysics Data System (ADS)

    Di Criscienzo, R.; Vanzo, L.

    2008-06-01

    The instability against emission of fermionic particles by the trapping horizon of an evolving black hole is analyzed and confirmed using the Hamilton-Jacobi tunneling method. This method automatically selects one special expression for the surface gravity of a changing horizon. The results also apply to point masses embedded in an expanding universe. As a bonus of the tunneling method, we gain the insight that the surface gravity still defines a temperature parameter as long as the evolution is sufficiently slow that the black-hole pass through a sequence of quasi-equilibrium states, and that black holes should be semi-classically unstable even in a hypothetical world without bosonic fields.

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

    PubMed

    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.

  5. Review of Aeronautical Wind Tunnel Facilities

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The nation's aeronautical wind tunnel facilities constitute a valuable technological resource and make a significant contribution to the global supremacy of U.S. aircraft, both civil and military. At the request of NASA, the National Research Council's Aeronautics and Space Engineering Board organized a commitee to review the state of repair, adequacy, and future needs of major aeronautical wind tunnel facilities in meeting national goals. The comittee identified three main areas where actions are needed to sustain the capability of NASA's aeronautical wind tunnel facilities to support the national aeronautical research and development activities: tunnel maintenance and upgrading, productivity enhancement, and accommodation of new requirements (particularly in hypersonics). Each of these areas are addressed and the committee recommendations for appropriate actions presented.

  6. Distance metrics for heme protein electron tunneling.

    PubMed

    Moser, Christopher C; Chobot, Sarah E; Page, Christopher C; Dutton, P Leslie

    2008-01-01

    There is no doubt that distance is the principal parameter that sets the order of magnitude for electron-tunneling rates in proteins. However, there continue to be varying ways to measure electron-tunneling distances in proteins. This distance uncertainty blurs the issue of whether the intervening protein medium has been naturally selected to speed or slow any particular electron-tunneling reaction. For redox cofactors lacking metals, an edge of the cofactor can be defined that approximates the extent in space that includes most of the wavefunction associated with its tunneling electron. Beyond this edge, the wavefunction tails off much more dramatically in space. The conjugated porphyrin ring seems a reasonable edge for the metal-free pheophytins and bacteriopheophytins of photosynthesis. For a metal containing redox cofactor such as heme, an appropriate cofactor edge is more ambiguous. Electron-tunneling distance may be measured from the conjugated heme macrocycle edge or from the metal, which can be up to 4.8 A longer. In a typical protein medium, such a distance difference normally corresponds to a approximately 1000 fold decrease in tunneling rate. To address this ambiguity, we consider both natural heme protein electron transfer and light-activated electron transfer in ruthenated heme proteins. We find that the edge of the conjugated heme macrocycle provides a reliable and useful tunneling distance definition consistent with other biological electron-tunneling reactions. Furthermore, with this distance metric, heme axially- and edge-oriented electron transfers appear similar and equally well described by a simple square barrier tunneling model. This is in contrast to recent reports for metal-to-metal metrics that require exceptionally poor donor/acceptor couplings to explain heme axially-oriented electron transfers.

  7. Aeroacoustic research in wind tunnels: A status report

    NASA Technical Reports Server (NTRS)

    Bender, J.; Arndt, R. E. A.

    1973-01-01

    The increasing attention given to aerodynamically generated noise brings into focus the need for quality experimental research in this area. To meet this need several specialized anechoic wind tunnels have been constructed. In many cases, however, budgetary constraints and the like make it desirable to use conventional wind tunnels for this work. Three basic problems are inherent in conventional facilities: (1) high background noise, (2) strong frequency dependent reverberation effects, and (3) unique instrumentation problems. The known acoustic characteristics of several conventional wind tunnels are evaluated and data obtained in a smaller 4- x 5-foot wind tunnel which is convertible from a closed jet to an open jet mode are presented. The data from these tunnels serve as a guideline for proposed modifications to a 7- x 10-foot wind tunnel. Consideration is given to acoustic treatment in several different portions of the wind tunnel.

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

    PubMed

    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.

  9. Fixed-Gap Tunnel Junction for Reading DNA Nucleotides

    PubMed Central

    2015-01-01

    Previous measurements of the electronic conductance of DNA nucleotides or amino acids have used tunnel junctions in which the gap is mechanically adjusted, such as scanning tunneling microscopes or mechanically controllable break junctions. Fixed-junction devices have, at best, detected the passage of whole DNA molecules without yielding chemical information. Here, we report on a layered tunnel junction in which the tunnel gap is defined by a dielectric layer, deposited by atomic layer deposition. Reactive ion etching is used to drill a hole through the layers so that the tunnel junction can be exposed to molecules in solution. When the metal electrodes are functionalized with recognition molecules that capture DNA nucleotides via hydrogen bonds, the identities of the individual nucleotides are revealed by characteristic features of the fluctuating tunnel current associated with single-molecule binding events. PMID:25380505

  10. Tunneling at νT=1 in quantum Hall bilayers

    NASA Astrophysics Data System (ADS)

    Nandi, D.; Khaire, T.; Finck, A. D. K.; Eisenstein, J. P.; Pfeiffer, L. N.; West, K. W.

    2013-10-01

    Interlayer tunneling measurements in the strongly correlated bilayer quantized Hall phase at νT=1 are reported. The maximum, or critical, current for tunneling at νT=1 is shown to be a well-defined global property of the coherent phase, insensitive to extrinsic circuit effects and the precise configuration used to measure it, but also exhibiting a surprising scaling behavior with temperature. Comparisons between the experimentally observed tunneling characteristics and a recent theory are favorable at high temperatures, but not at low temperatures where the tunneling closely resembles the dc Josephson effect. The zero-bias tunneling resistance becomes extremely small at low temperatures, vastly less than that observed at zero magnetic field, but nonetheless remains finite. The temperature dependence of this tunneling resistance is similar to that of the ordinary in-plane resistivity of the quantum Hall phase.

  11. The cryogenic wind tunnel

    NASA Technical Reports Server (NTRS)

    Kilgore, R. A.

    1976-01-01

    Based on theoretical studies and experience with a low speed cryogenic tunnel and with a 1/3-meter transonic cryogenic tunnel, the cryogenic wind tunnel concept was shown to offer many advantages with respect to the attainment of full scale Reynolds number at reasonable levels of dynamic pressure in a ground based facility. The unique modes of operation available in a pressurized cryogenic tunnel make possible for the first time the separation of Mach number, Reynolds number, and aeroelastic effects. By reducing the drive-power requirements to a level where a conventional fan drive system may be used, the cryogenic concept makes possible a tunnel with high productivity and run times sufficiently long to allow for all types of tests at reduced capital costs and, for equal amounts of testing, reduced total energy consumption in comparison with other tunnel concepts.

  12. Distribution of tunnelling times for quantum electron transport

    NASA Astrophysics Data System (ADS)

    Rudge, Samuel L.; Kosov, Daniel S.

    2016-03-01

    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.

  13. Charge Islands Through Tunneling

    NASA Technical Reports Server (NTRS)

    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.

  14. Inelastic tunnel diodes

    NASA Technical Reports Server (NTRS)

    Anderson, L. M. (Inventor)

    1984-01-01

    Power is extracted from plasmons, photons, or other guided electromagnetic waves at infrared to midultraviolet frequencies by inelastic tunneling in metal-insulator-semiconductor-metal diodes. Inelastic tunneling produces power by absorbing plasmons to pump electrons to higher potential. Specifically, an electron from a semiconductor layer absorbs a plasmon and simultaneously tunnels across an insulator into metal layer which is at higher potential. The diode voltage determines the fraction of energy extracted from the plasmons; any excess is lost to heat.

  15. Resonance enhanced tunneling

    NASA Astrophysics Data System (ADS)

    Matsumoto, S.; Yoshimura, M.

    2000-12-01

    Time evolution of tunneling in thermal medium is examined using the real-time semiclassical formalism previously developed. Effect of anharmonic terms in the potential well is shown to give a new mechanism of resonance enhanced tunneling. If the friction from environment is small enough, this mechanism may give a very large enhancement for the tunneling rate. The case of the asymmetric wine bottle potential is worked out in detail.

  16. Tunnel closure calculations

    SciTech Connect

    Moran, B.; Attia, A.

    1995-07-01

    When a deeply penetrating munition explodes above the roof of a tunnel, the amount of rubble that falls inside the tunnel is primarily a function of three parameters: first the cube-root scaled distance from the center of the explosive to the roof of the tunnel. Second the material properties of the rock around the tunnel, and in particular the shear strength of that rock, its RQD (Rock Quality Designator), and the extent and orientation of joints. And third the ratio of the tunnel diameter to the standoff distance (distance between the center of explosive and the tunnel roof). The authors have used CALE, a well-established 2-D hydrodynamic computer code, to calculate the amount of rubble that falls inside a tunnel as a function of standoff distance for two different tunnel diameters. In particular they calculated three of the tunnel collapse experiments conducted in an iron ore mine near Kirkeness, Norway in the summer of 1994. The failure model that they used in their calculations combines an equivalent plastic strain criterion with a maximum tensile strength criterion and can be calibrated for different rocks using cratering data as well as laboratory experiments. These calculations are intended to test and improve the understanding of both the Norway Experiments and the ACE (Array of conventional Explosive) phenomenology.

  17. Atom Tunneling in Chemistry.

    PubMed

    Meisner, Jan; Kästner, Johannes

    2016-04-25

    Quantum mechanical tunneling of atoms is increasingly found to play an important role in many chemical transformations. Experimentally, atom tunneling can be indirectly detected by temperature-independent rate constants at low temperature or by enhanced kinetic isotope effects. In contrast, the influence of tunneling on the reaction rates can be monitored directly through computational investigations. The tunnel effect, for example, changes reaction paths and branching ratios, enables chemical reactions in an astrochemical environment that would be impossible by thermal transition, and influences biochemical processes. PMID:26990917

  18. 5. VIEW LOOKING NORTH AT 8FOOT TRANSONIC PRESSURE TUNNEL PLENUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW LOOKING NORTH AT 8-FOOT TRANSONIC PRESSURE TUNNEL PLENUM FLOOR AREA. NOTE SCHLIEREN OPTICAL SYSTEM ON STRUCTURE AT RIGHT CENTER. - NASA Langley Research Center, 8-Foot Transonic Pressure Tunnel, 640 Thornell Avenue, Hampton, Hampton, VA

  19. Thermodynamics of phonon-modulated tunneling centers

    SciTech Connect

    Junker, W.; Wagner, M. )

    1989-08-01

    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.

  20. V/STOL wind-tunnel testing

    NASA Technical Reports Server (NTRS)

    Koenig, D. G.

    1984-01-01

    Factors influencing effective program planning for V/STOL wind-tunnel testing are discussed. The planning sequence itself, which includes a short checklist of considerations that could enhance the value of the tests, is also described. Each of the considerations, choice of wind tunnel, type of model installation, model development and test operations is discussed, and examples of appropriate past and current V/STOL test programs are provided. A short survey of the moderate to large subsonic wind tunnels is followed by a review of several model installations, from dimensional to large-scale models of complete aircraft configurations. Model sizing, power simulation, and planning are treated, including three areas in test operations: data acquisition systems, acoustic measurements in wind tunnels, and flow surveying.

  1. V/STOL wind-tunnel testing

    NASA Technical Reports Server (NTRS)

    Koenig, D. G.

    1984-01-01

    Factors influencing effective program planning for V/STOL wind-tunnel testing are discussed. The planning sequence itself, which includes a short checklist of considerations that could enhance the value of the tests, is also described. Each of the considerations, choice of wind tunnel, type of model installation, model development and test operations, is discussed, and examples of appropriate past and current V/STOL test programs are provided. A short survey of the moderate to large subsonic wind tunnels is followed by a review of several model installations, from two-dimensional to large-scale models of complete aircraft configurations. Model sizing, power simulation, and planning are treated, including three areas is test operations: data-acquisition systems, acoustic measurements in wind tunnels, and flow surveying.

  2. The Design of Low-Turbulence Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Dryden, Hugh L; Abbott, Ira H

    1949-01-01

    Within the past 10 years there have been placed in operation in the United States four low-turbulence wind tunnels of moderate cross-sectional area and speed, one at the National Bureau of Standards, two at the NACA Langley Laboratory, and one at the NACA Ames Laboratory. This paper reviews briefly the state of knowledge and those features which make possible the attainment of low turbulence in wind tunnels. Specific applications to two wind tunnels are described.

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

    NASA Technical Reports Server (NTRS)

    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.

  4. LOFT. Construction view of tunnel during 1957 to compare with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LOFT. Construction view of tunnel during 1957 to compare with HAER photo ID-33-E-358 above. Tunnel sections were pre-cast, then joined together. Photographer described this as :Personnel and service tunnel running east-west in test building of the FET." Date: December 19, 1957. Photographer: Jack L. Anderson. INEEL negative no. 57-6206 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

  5. Shotcrete in tunnel design

    SciTech Connect

    Golser, J.; Galler, R.; Schubert, P.; Rabensteiner, K.

    1995-12-31

    Shotcrete is an important structural element for tunnel support. Green shotcrete is exposed to compression strain rates and tunnel design requires a realistic material law for shotcrete. A modified rate of flow method simulates shotcrete behavior very well and can be incorporated in Finite Element calculations.

  6. Micromachined Tunneling Accelerometer

    NASA Technical Reports Server (NTRS)

    Kenny, Thomas W.; Waltman, Stephen B.; Kaiser, William J.; Reynolds, Joseph K.

    1993-01-01

    Separation of tunneling electrodes adjusted by varying electrostatic force. Major components of tunneling transducer formed on two silicon chips by microfabrication techniques. Use of electrostatic deflection reduces sensitivity of transducer to thermal drift and simplifies design. Sensitivity suitable for applications in which larger acceleration-sensing instruments required.

  7. The carpal tunnel.

    PubMed

    Ellis, Harold

    2009-12-01

    The carpal bones are deeply convex anteriorly. This bony gutter is converted by the flexor retinaculum into a tube - the carpal tunnel, which conveys the median nerve, together with the long flexor tendons of the fingers and thumb, into the hand. It is of special interest to the surgeon because it is the site of a common nerve entrapment, the carpal tunnel syndrome.

  8. TAPERED DEFINING SLOT

    DOEpatents

    Pressey, F.W.

    1959-09-01

    An improvement is reported in the shape and formation of the slot or opening in the collimating slot member which forms part of an ion source of the type wherein a vapor of the material to be ionized is bombarded by electrons in a magnetic field to strike an arc-producing ionization. The defining slot is formed so as to have a substantial taper away from the cathode, causing the electron bombardment from the cathode to be dispersed over a greater area reducing its temperature and at the same time bringing the principal concentration of heat from the electron bombardment nearer the anode side of the slot, thus reducing deterioration and prolonging the life of the slot member during operation.

  9. Defining critical thoughts.

    PubMed

    Lovatt, Abbie

    2014-05-01

    Nursing education has long struggled to define critical thinking and explain how the process of critical thinking fits into the context of nursing. Despite this long time struggle, nurses and nurse educators continue to strive to foster critical thinking skills in nursing students as intuitively most nurses believe that critical thinking is necessary to function competently in the workplace. This article explores the most recent work of Dr. Stephen Brookfield and ties the concepts which are explored in Brookfield's work to nursing practice. Brookfield identifies that learners understand the meaning of critical thinking the best when the process is first demonstrated. Role modeling is a method educators can use to demonstrate critical thinking and is a strategy which nurses often use in the clinical area to train and mentor new nursing staff. Although it is not a new strategy in nursing education, it is a valuable strategy to engage learners in critical thinking activities. PMID:24418065

  10. Treatment of tunnel phobia: an experimental field study.

    PubMed

    Gotestam, K Gunnar; Svebak, Sven

    2009-01-01

    The opening of the deepest undersea tunnel in the world (264 m below sea level, 5600 m in length) replaced the ferry from the island of Hitra to the mainland in Norway. This event provoked phobic anxiety for traveling through the undersea tunnel in a number of individuals in the area. A treatment program for tunnel phobia was designed to test whether such a phobia could be mitigated by procedures previously proven effective in the treatment of other phobias. The program was presented to 18 persons with a specific phobia for tunnels and included a general discussion on the construction of undersea tunnels, given by an engineer from the tunnel construction company, and on phobic anxiety. It further consisted of gradual exposure to the tunnel in situ. Treatment effects were strong. All patients were able to travel on their own by car through the tunnel after the treatment. Their somatic complaints and phobic thoughts related to the tunnel were substantially reduced, and their mastery of tunnel driving was convincingly increased compared with the wait-list reference group. PMID:19440895

  11. Treatment of tunnel phobia: an experimental field study.

    PubMed

    Gotestam, K Gunnar; Svebak, Sven

    2009-01-01

    The opening of the deepest undersea tunnel in the world (264 m below sea level, 5600 m in length) replaced the ferry from the island of Hitra to the mainland in Norway. This event provoked phobic anxiety for traveling through the undersea tunnel in a number of individuals in the area. A treatment program for tunnel phobia was designed to test whether such a phobia could be mitigated by procedures previously proven effective in the treatment of other phobias. The program was presented to 18 persons with a specific phobia for tunnels and included a general discussion on the construction of undersea tunnels, given by an engineer from the tunnel construction company, and on phobic anxiety. It further consisted of gradual exposure to the tunnel in situ. Treatment effects were strong. All patients were able to travel on their own by car through the tunnel after the treatment. Their somatic complaints and phobic thoughts related to the tunnel were substantially reduced, and their mastery of tunnel driving was convincingly increased compared with the wait-list reference group.

  12. Systems tunnel linear shaped charge lightning strike

    NASA Technical Reports Server (NTRS)

    Cook, M.

    1989-01-01

    Simulated lightning strike testing of the systems tunnel linear shaped charge (LSC) was performed at the Thiokol Lightning Test Complex in Wendover, Utah, on 23 Jun. 1989. The test article consisted of a 160-in. section of the LSC enclosed within a section of the systems tunnel. The systems tunnel was bonded to a section of a solid rocket motor case. All test article components were full scale. The systems tunnel cover of the test article was subjected to three discharges (each discharge was over a different grounding strap) from the high-current generator. The LSC did not detonate. All three grounding straps debonded and violently struck the LSC through the openings in the systems tunnel floor plates. The LSC copper surface was discolored around the areas of grounding strap impact, and arcing occurred at the LSC clamps and LSC ends. This test verified that the present flight configuration of the redesigned solid rocket motor systems tunnel, when subjected to simulated lightning strikes with peak current levels within 71 percent of the worst-case lightning strike condition of NSTS-07636, is adequate to prevent LSC ignition. It is therefore recommended that the design remain unchanged.

  13. Variable-Density Tunnel - Wind Tunnel #2

    NASA Technical Reports Server (NTRS)

    1923-01-01

    Underside of the Variable-Density Tunnel (VDT). The compressors are to the left. Circular screened cone is shown. The photographer was probably shooting film for Dr. Joseph Ames' Wilbur Wright Memorial Lecture given to the Royal Aeronautical Society on May 31, 1923.

  14. Autonomous Robotic Inspection in Tunnels

    NASA Astrophysics Data System (ADS)

    Protopapadakis, E.; Stentoumis, C.; Doulamis, N.; Doulamis, A.; Loupos, K.; Makantasis, K.; Kopsiaftis, G.; Amditis, A.

    2016-06-01

    In this paper, an automatic robotic inspector for tunnel assessment is presented. The proposed platform is able to autonomously navigate within the civil infrastructures, grab stereo images and process/analyse them, in order to identify defect types. At first, there is the crack detection via deep learning approaches. Then, a detailed 3D model of the cracked area is created, utilizing photogrammetric methods. Finally, a laser profiling of the tunnel's lining, for a narrow region close to detected crack is performed; allowing for the deduction of potential deformations. The robotic platform consists of an autonomous mobile vehicle; a crane arm, guided by the computer vision-based crack detector, carrying ultrasound sensors, the stereo cameras and the laser scanner. Visual inspection is based on convolutional neural networks, which support the creation of high-level discriminative features for complex non-linear pattern classification. Then, real-time 3D information is accurately calculated and the crack position and orientation is passed to the robotic platform. The entire system has been evaluated in railway and road tunnels, i.e. in Egnatia Highway and London underground infrastructure.

  15. Variable-Density Tunnel - Wind Tunnel #2

    NASA Technical Reports Server (NTRS)

    1922-01-01

    Equipment used for pressurizing the Variable-Density Tunnel (VDT): The VDT tunnel is on the right; the compressors are on the left. Figure 4 in the NACA Technical Report 227 (Part 2) identifies each piece of equipment visible in this diagram. Immediately visible in the lower left corner is the Booster Compressor. In the right rear (behind the tunnel) is Primary Compressor No. 1. (Primary Compressor No. 2 is not visible.) From NACA TR 227 (Part 2):'The air is compressed in two or three stages, according to the terminal pressure in the tank. A two-stage primary compressor is used up to a terminal pressure of about seven atmospheres. For pressures above this a booster compressor is used in conjunction with the primary compressor. The booster compressor may be used also as an exhauster when it is desired to operate the tunnel at pressures below that of the atmosphere. The primary compressors are driven by 250-horsepower synchronous motors and the booster compressor by a 150-horsepower squirrel-cage induction motor.' Jerome Hunsaker wrote in 'Forty Years of Aeronautical Research': 'In June 1921, the executive committee [of the NACA] decided to build a new kind of wind tunnel. Utilizing compressed air, it would allow for *scale effects in aerodynamic model experiments. This tunnel represented the first bold step by the NACA to provide its research personnel with the novel, often complicated, and usually expensive equipment necessary to press forward the frontiers of aeronautical science. It was designed by Dr. Max Munk, formerly of G*ttingen.' Eastman Jacobs wrote in an article in a 1927 article for Aviation that: 'The tunnel is inclosed (sic) within a steel shell, so that the density of the air inside may be increased by pumping air into the shell to a pressure of 300 lb. per sq. in. A 250 hp. motor, driving a propeller, circulates the air, drawing it through the five-foot test section at a velocity of about fifty miles per hour. The model is mounted in the throat of

  16. 14. EXTERIOR VIEW OF OLD TENFOOT WIND TUNNEL (1991). ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. EXTERIOR VIEW OF OLD TEN-FOOT WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  17. 13. EXTERIOR VIEW OF OLD TENFOOT WIND TUNNEL (1991). ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. EXTERIOR VIEW OF OLD TEN-FOOT WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  18. Screens Would Protect Wind-Tunnel Fan Blades

    NASA Technical Reports Server (NTRS)

    Farmer, Moses G.

    1992-01-01

    Butterfly screen installed in wind tunnel between test section and fan blades to prevent debris from reaching fan blades if model structure fails. Protective screens deployed manually or automatically. Concept beneficial anywhere wind tunnels employed. Also useful in areas outside of aerospace industry, such as in airflow design of automobiles and other vehicles.

  19. Ultrafast scanning tunneling microscopy

    SciTech Connect

    Botkin, D.A. |

    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.

  20. Pre-Test Assessment of the Use Envelope of the Normal Force of a Wind Tunnel Strain-Gage Balance

    NASA Technical Reports Server (NTRS)

    Ulbrich, N.

    2016-01-01

    The relationship between the aerodynamic lift force generated by a wind tunnel model, the model weight, and the measured normal force of a strain-gage balance is investigated to better understand the expected use envelope of the normal force during a wind tunnel test. First, the fundamental relationship between normal force, model weight, lift curve slope, model reference area, dynamic pressure, and angle of attack is derived. Then, based on this fundamental relationship, the use envelope of a balance is examined for four typical wind tunnel test cases. The first case looks at the use envelope of the normal force during the test of a light wind tunnel model at high subsonic Mach numbers. The second case examines the use envelope of the normal force during the test of a heavy wind tunnel model in an atmospheric low-speed facility. The third case reviews the use envelope of the normal force during the test of a floor-mounted semi-span model. The fourth case discusses the normal force characteristics during the test of a rotated full-span model. The wind tunnel model's lift-to-weight ratio is introduced as a new parameter that may be used for a quick pre-test assessment of the use envelope of the normal force of a balance. The parameter is derived as a function of the lift coefficient, the dimensionless dynamic pressure, and the dimensionless model weight. Lower and upper bounds of the use envelope of a balance are defined using the model's lift-to-weight ratio. Finally, data from a pressurized wind tunnel is used to illustrate both application and interpretation of the model's lift-to-weight ratio.

  1. Defining an emerging disease.

    PubMed

    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. PMID:26470448

  2. Defining an emerging disease.

    PubMed

    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.

  3. 30 CFR 77.211 - Draw-off tunnels; stockpiling and reclaiming operations; general.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Draw-off tunnels; stockpiling and reclaiming... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.211 Draw-off tunnels; stockpiling and reclaiming operations; general. (a) Tunnels located below stockpiles, surge piles, and coal storage...

  4. 30 CFR 77.211 - Draw-off tunnels; stockpiling and reclaiming operations; general.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Draw-off tunnels; stockpiling and reclaiming... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.211 Draw-off tunnels; stockpiling and reclaiming operations; general. (a) Tunnels located below stockpiles, surge piles, and coal storage...

  5. 30 CFR 77.211 - Draw-off tunnels; stockpiling and reclaiming operations; general.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Draw-off tunnels; stockpiling and reclaiming... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.211 Draw-off tunnels; stockpiling and reclaiming operations; general. (a) Tunnels located below stockpiles, surge piles, and coal storage...

  6. 30 CFR 77.211 - Draw-off tunnels; stockpiling and reclaiming operations; general.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Draw-off tunnels; stockpiling and reclaiming... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.211 Draw-off tunnels; stockpiling and reclaiming operations; general. (a) Tunnels located below stockpiles, surge piles, and coal storage...

  7. 30 CFR 77.211 - Draw-off tunnels; stockpiling and reclaiming operations; general.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Draw-off tunnels; stockpiling and reclaiming... WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.211 Draw-off tunnels; stockpiling and reclaiming operations; general. (a) Tunnels located below stockpiles, surge piles, and coal storage...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  9. Quantum tunneling beyond semiclassical approximation

    NASA Astrophysics Data System (ADS)

    Banerjee, Rabin; Ranjan Majhi, Bibhas

    2008-06-01

    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.

  10. Carpal Tunnel Syndrome

    MedlinePlus

    ... through NIH's National Center for Complementary and Alternative Medicine are investigating the effects of acupuncture on pain, loss of median nerve function, and changes in the brain associated with carpal tunnel syndrome. In addition, a ...

  11. RITD – Wind tunnel testing

    NASA Astrophysics Data System (ADS)

    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

  12. Channel-tunnels.

    PubMed

    Koronakis, V; Andersen, C; Hughes, C

    2001-08-01

    TolC and its many homologues comprise an alpha-helical transperiplasmic tunnel embedded in the bacterial outer membrane by a contiguous beta-barrel channel, providing a large exit duct for diverse substrates. The 'channel-tunnel' is closed at its periplasmic entrance, but can be opened by an 'iris-like' mechanism when recruited by substrate-engaged proteins in the cytosolic membrane.

  13. Silicon-germanium nanowire tunnel-FETs with homo- and heterostructure tunnel junctions

    NASA Astrophysics Data System (ADS)

    Richter, S.; Blaeser, S.; Knoll, L.; Trellenkamp, S.; Fox, A.; Schäfer, A.; Hartmann, J. M.; Zhao, Q. T.; Mantl, S.

    2014-08-01

    Experimental results on tunneling field-effect transistors (TFETs) based on strained SiGe on SOI nanowire arrays are presented. A heterostructure SiGe/Si TFET with a vertical tunnel junction consisting of an in situ doped SiGe source and a Si channel with a minimum inverse subthreshold slope of 90 mV/dec is demonstrated. An increase in tunneling area results in higher on-current. The in situ doped heterojunction TFET shows great improvement compared to a homojunction SiGe on SOI nanowire design with implanted junctions. Temperature dependent measurements and device simulations are performed in order to analyze the tunnel transport mechanism in the devices.

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

    NASA Technical Reports Server (NTRS)

    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.

  15. Shock tunnel studies of scramjet phenomena

    NASA Technical Reports Server (NTRS)

    Morgan, R. G.; Paull, A.; Stalker, R. J.; Jacobs, P.; Morris, N.; Stringer, I.; Brescianini, C.

    1988-01-01

    Commissioning of the new T4 shock tunnel at the University of Queensland implied that it was no longer necessary to focus the work of the research group about an annual test series conducted in the T3 shock tunnel in Canberra. Therefore, it has been possible to organize a group for work to proceed along lines such that particular personnel are associated with particular project areas. The format of this report consists of a series of reports on specific project areas, with a brief general introduction commenting on each report. The introduction is structured by project areas, with the title of the relevant report stated under the project area heading. The reports themselves follow in the order of the project area headings.

  16. Employees' Knowledge of Carpal Tunnel Syndrome.

    ERIC Educational Resources Information Center

    Gandy-Goldston, Terrie M.

    A study examined employees' knowledge of the causes of carpal tunnel syndrome (CTS), its prevention, and their legal rights after being diagnosed with CTS. A 24-item questionnaire was administered to a random sample of 30 Chicago-area employees who had been afflicted with CTS. Of those surveyed, 99% considered their CTS injury related to their…

  17. Unipolar complementary circuits using double electron layer tunneling transistors

    SciTech Connect

    Moon, J.S.; Simmons, J.A.; Blount, M.A.; Reno, J.L.; Hafich, M.J.

    1999-01-01

    We demonstrate unipolar complementary circuits consisting of a pair of resonant tunneling transistors based on the gate control of two-dimensional{endash}two-dimensional interlayer tunneling, where a single transistor{emdash}in addition to exhibiting a well-defined negative-differential resistance{emdash}can be operated with either positive or negative transconductance. Details of the device operation are analyzed in terms of the quantum capacitance effect and bandbending in a double quantum well structure, and show good agreement with experiment. Application of resonant tunneling complementary logic is discussed by demonstrating complementary static random access memory using two devices connected in series. {copyright} {ital 1999 American Institute of Physics.}

  18. Single to quadruple quantum dots with tunable tunnel couplings

    SciTech Connect

    Takakura, T.; Noiri, A.; Obata, T.; Yoneda, J.; Yoshida, K.; Otsuka, T.; Tarucha, S.

    2014-03-17

    We prepare a gate-defined quadruple quantum dot to study the gate-tunability of single to quadruple quantum dots with finite inter-dot tunnel couplings. The measured charging energies of various double dots suggest that the dot size is governed by the gate geometry. For the triple and quadruple dots, we study the gate-tunable inter-dot tunnel couplings. For the triple dot, we find that the effective tunnel coupling between side dots significantly depends on the alignment of the center dot potential. These results imply that the present quadruple dot has a gate performance relevant for implementing spin-based four-qubits with controllable exchange couplings.

  19. Wall Interference in Two-Dimensional Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Kemp, William B., Jr.

    1986-01-01

    Viscosity and tunnel-wall constraints introduced via boundary conditions. TWINTN4 computer program developed to implement method of posttest assessment of wall interference in two-dimensional wind tunnels. Offers two methods for combining sidewall boundary-layer effects with upper and lower wall interference. In sequential procedure, Sewall method used to define flow free of sidewall effects, then assessed for upper and lower wall effects. In unified procedure, wind-tunnel flow equations altered to incorporate effects from all four walls at once. Program written in FORTRAN IV for batch execution.

  20. 13. VIEW FROM COLD CALIBRATION BLOCKHOUSE LOOKING DOWN CONNECTING TUNNEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. VIEW FROM COLD CALIBRATION BLOCKHOUSE LOOKING DOWN CONNECTING TUNNEL TO COLD CALIBRATION TEST STAND BASEMENT, SHOWING HARD WIRE CONNECTION (INSTRUMENTATION AND CONTROL). - Marshall Space Flight Center, East Test Area, Cold Calibration Test Stand, Huntsville, Madison County, AL

  1. 7. BLOCK HOUSE BASEMENT LOOKING THROUGH DOOR INTO CABLE TUNNEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. BLOCK HOUSE BASEMENT LOOKING THROUGH DOOR INTO CABLE TUNNEL RUNNING BETWEEN BLOCK HOUSE AND STATIC TEST TOWER. - Marshall Space Flight Center, East Test Area, Block House, Huntsville, Madison County, AL

  2. A multidisciplinary geological and geophysical approach to define structural and hydrogeological implications of the Molinaccio spring (Spello, Italy)

    NASA Astrophysics Data System (ADS)

    Ercoli, Maurizio; Pauselli, Cristina; Forte, Emanuele; Di Matteo, Lucio; Mazzocca, Massimiliano; Frigeri, Alessandro; Federico, Costanzo

    2012-02-01

    In this paper, a multidisciplinary geological and geophysical approach has been applied in the complex area of Molinaccio spring (Spello, Umbria, Central Italy) to: 1) understand the large-scale geologic and tectonic structure of the area; 2) define the hydrogeological behavior of the various formations in relationship with the identified structural elements; 3) highlight at small-scale the tectonic structures and their relationships with the water caption tunnel, which is the draining structure of a still working, ancient Roman aqueduct giving water to the village of Spello and to the surrounding plain. Our approach includes different techniques like Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT), direct geological investigations, archaeological studies, GIS data collection and integration. The GPR data revealed, in the area of the water-caption tunnel, two main tectonic structures, both also confirmed by ERT data: the presence of a zone (maximum 2 m wide), interpreted as a normal fault area and an overthrust that puts in contact the permeable Scaglia Rossa limestone (Early Turonian-Middle Eocene), and the Scaglia Variegata-Cinerea marly limestones (Middle Eocene-Upper Oligocene) on the footwall, characterized by lower hydraulic permeability. Using some rough information available on the sub-surface path of the tunnel, that shows a sharp bend after a long straight course, together with the geophysical images, was possible to describe how Romans built the tunnel: they probably followed the wet outcropping rock during the excavation, and changed abruptly the dig direction when they intercepted the normal fault area, aligning then the excavation along its strike. This latter result is important also because recently a multidisciplinary project has been developed to restore and exploit the entire water supply structure, which is not only a well-preserved example of Roman remains with high archaeological value, but also a vital

  3. Uncooled tunneling infrared sensor

    NASA Technical Reports Server (NTRS)

    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.

  4. 203. Lickstone Ridge Tunnel. All but three of the tunnel ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    203. Lickstone Ridge Tunnel. All but three of the tunnel have minimum height of 13, which accommodates most large recreational vehicles. This tunnel has the lowest clearance at 11-3. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  5. View down tank tunnel (tunnel no. 2) showing pipes and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View down tank tunnel (tunnel no. 2) showing pipes and walkway of metal grating, side tunnel to tank 3 is on the left - U.S. Naval Base, Pearl Harbor, Diesel Purification Plant, North Road near Pierce Street, Pearl City, Honolulu County, HI

  6. Aorto-ventricular tunnel.

    PubMed

    McKay, Roxane

    2007-10-08

    Aorto-ventricular tunnel is a congenital, extracardiac channel which connects the ascending aorta above the sinutubular junction to the cavity of the left, or (less commonly) right ventricle. The exact incidence is unknown, estimates ranging from 0.5% of fetal cardiac malformations to less than 0.1% of congenitally malformed hearts in clinico-pathological series. Approximately 130 cases have been reported in the literature, about twice as many cases in males as in females. Associated defects, usually involving the proximal coronary arteries, or the aortic or pulmonary valves, are present in nearly half the cases. Occasional patients present with an asymptomatic heart murmur and cardiac enlargement, but most suffer heart failure in the first year of life. The etiology of aorto-ventricular tunnel is uncertain. It appears to result from a combination of maldevelopment of the cushions which give rise to the pulmonary and aortic roots, and abnormal separation of these structures. Echocardiography is the diagnostic investigation of choice. Antenatal diagnosis by fetal echocardiography is reliable after 18 weeks gestation. Aorto-ventricular tunnel must be distinguished from other lesions which cause rapid run-off of blood from the aorta and produce cardiac failure. Optimal management of symptomatic aorto-ventricular tunnel consists of diagnosis by echocardiography, complimented with cardiac catheterization as needed to elucidate coronary arterial origins or associated defects, and prompt surgical repair. Observation of the exceedingly rare, asymptomatic patient with a small tunnel may be justified by occasional spontaneous closure. All patients require life-long follow-up for recurrence of the tunnel, aortic valve incompetence, left ventricular function, and aneurysmal enlargement of the ascending aorta.

  7. Defining Early Adolescent Childbearing.

    ERIC Educational Resources Information Center

    Phipps, Maureen G.; Sowers, MaryFran

    2002-01-01

    Determined the age group for defining early adolescent childbearing based on rates of adverse clinical outcomes. Data on infant mortality, very low birth weight, and very pre-term delivery per 1,000 live births for women age 12-23 years in the 1995 U.S. birth cohort indicate that early adolescent childbearing is best defined as giving birth at age…

  8. The Path Decomposition Expansion and Multidimensional Tunneling

    NASA Astrophysics Data System (ADS)

    Auerbach, Assa

    The dissertation consists of two main topics. (a) The Path Decomposition Expansion (PDX): A new path integral technique which allows us to break configuration space into disjoint regions, and express the dynamics of the full system in terms of its parts. (b) The application of the PDX and semiclassical methods for solving quantum -mechanical problems in multidimensions. The result is a conceptually simple, computationally straightforward method for calculating tunneling effects in complicated multidimensional potentials, even in cases where the nature of the states in the classically allowed regions in nontrivial. Algorithms for computing tunneling effects in general classes of problems are obtained. The detailed solutions to several model problems are presented. These enable us to define various well -controlled approximation schemes, which help to reduce the dimensions of complicated tunneling calculations in real physical systems. The dramatic effects of transverse fluctuations on the asymptotic behavior of the groundstate tunnel-splitting are studied also in potentials with non -quadratic minima where standard instanton techniques fail. The power of the PDX is demonstrated by a calculation of the optical absorption coefficient of trans-polyacetylene where large amplitude (non-perturbative) quantum fluctuations of the lattice play an important role in determining the sub-gap absorption tail. Good agreement with experimental data is found, and suggestions for further measurements in this regime are made.

  9. Magnetic Tunnel Junctions

    NASA Astrophysics Data System (ADS)

    Reiss, Günter; Schmalhorst, Jan; Thomas, Andre; Hütten, Andreas; Yuasa, Shinji

    In magnetoelectronic devices large opportunities are opened by the spin dependent tunneling resistance, where a strong dependence of the tunneling current on the relative orientation of the magnetization of the electrodes is found. Within a short time, the amplitude of the resistance change of the junctions increased dramatically. We will cover Al-O and MgO based junctions and present highly spin-polarized electrode materials such as Heusler alloys. Furthermore, we will give a short overview on applications such as read heads in hard disk drives, storage cells in MRAMs, field programmable logic circuits and biochips. Finally, we will discuss the currently growing field of current induced magnetization switching.

  10. Tunneling in axion monodromy

    NASA Astrophysics Data System (ADS)

    Brown, Jon; Cottrell, William; Shiu, Gary; Soler, Pablo

    2016-10-01

    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.

  11. Eliminating Wind Tunnel Flow Breakdown

    NASA Technical Reports Server (NTRS)

    Hackett, J. E.

    1983-01-01

    Undesirable vortexes near floor in small wind tunnels suppressed by simple device that alters flow pattern there. Air is injected along floor and interacts with backflow from wind-tunnel model. Results in smoother, more correct air-flow and to more-reliable wind-tunnel data.

  12. Propeller Research Tunnel

    NASA Technical Reports Server (NTRS)

    1926-01-01

    This picture shows a general view of the Propeller Research Tunnel engine room under construction. Workmen were installing the two submarine diesel engines that would power the PRT. The room was constructed of concrete with corrugated metal siding and roofing with the intention of making the engine room as fireproof as possible.

  13. Prions tunnel between cells.

    PubMed

    Gerdes, Hans-Hermann

    2009-03-01

    Prions are abnormal isoforms of host proteins that are the infectious agents in certain mammalian neurodegenerative diseases. How prions travel from their peripheral entry sites to the brain where they cause disease is poorly understood. A new study finds that tunnelling nanotubes are important for the intercellular transfer of prions during neuroinvasion.

  14. Tunnelling with wormhole creation

    SciTech Connect

    Ansoldi, S.; Tanaka, T.

    2015-03-15

    The description of quantum tunnelling in the presence of gravity shows subtleties in some cases. We discuss wormhole production in the context of the spherically symmetric thin-shell approximation. By presenting a fully consistent treatment based on canonical quantization, we solve a controversy present in the literature.

  15. Carpal Tunnel Syndrome

    PubMed Central

    Mahoney, James Leo; Dagum, Alexander B.

    1992-01-01

    Carpal tunnel syndrome is a very common hand problem usually presenting with nighttime pain, numbness, and loss of dexterity. Controversy arises over the diagnosis, treatment, and evaluation of results. Nighttime splinting will improve the symptoms in some patients. If this fails, excellent results can be achieved with surgical decompression of the median nerve in the carpal canal. PMID:21221355

  16. Full Scale Tunnel model

    NASA Technical Reports Server (NTRS)

    1929-01-01

    Interior view of Full-Scale Tunnel (FST) model. (Small human figures have been added for scale.) On June 26, 1929, Elton W. Miller wrote to George W. Lewis proposing the construction of a model of the full-scale tunnel . 'The excellent energy ratio obtained in the new wind tunnel of the California Institute of Technology suggests that before proceeding with our full scale tunnel design, we ought to investigate the effect on energy ratio of such factors as: 1. small included angle for the exit cone; 2. carefully designed return passages of circular section as far as possible, without sudden changes in cross sections; 3. tightness of walls. It is believed that much useful information can be obtained by building a model of about 1/16 scale, that is, having a closed throat of 2 ft. by 4 ft. The outside dimensions would be about 12 ft. by 25 ft. in plan and the height 4 ft. Two propellers will be required about 28 in. in diameter, each to be driven by direct current motor at a maximum speed of 4500 R.P.M. Provision can be made for altering the length of certain portions, particularly the exit cone, and possibly for the application of boundary layer control in order to effect satisfactory air flow.

  17. Dry wind tunnel system

    NASA Technical Reports Server (NTRS)

    Chen, Ping-Chih (Inventor)

    2013-01-01

    This invention is a ground flutter testing system without a wind tunnel, called Dry Wind Tunnel (DWT) System. The DWT system consists of a Ground Vibration Test (GVT) hardware system, a multiple input multiple output (MIMO) force controller software, and a real-time unsteady aerodynamic force generation software, that is developed from an aerodynamic reduced order model (ROM). The ground flutter test using the DWT System operates on a real structural model, therefore no scaled-down structural model, which is required by the conventional wind tunnel flutter test, is involved. Furthermore, the impact of the structural nonlinearities on the aeroelastic stability can be included automatically. Moreover, the aeroservoelastic characteristics of the aircraft can be easily measured by simply including the flight control system in-the-loop. In addition, the unsteady aerodynamics generated computationally is interference-free from the wind tunnel walls. Finally, the DWT System can be conveniently and inexpensively carried out as a post GVT test with the same hardware, only with some possible rearrangement of the shakers and the inclusion of additional sensors.

  18. The Channel Tunnel

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The Channel Tunnel is a 50.5 km-long rail tunnel beneath the English Channel at the Straits of Dover. It connects Dover, Kent in England with Calais, northern France. The undersea section of the tunnel is unsurpassed in length in the world. A proposal for a Channel tunnel was first put forward by a French engineer in 1802. In 1881, a first attempt was made at boring a tunnel from the English side; the work was halted after 800 m. Again in 1922, English workers started boring a tunnel, and advanced 120 m before it too was halted for political reasons. The most recent attempt was begun in 1987, and the tunnel was officially opened in 1994. At completion it was estimated that the project cost around $18 billion. It has been operating at a significant loss since its opening, despite trips by over 7 million passengers per year on the Eurostar train, and over 3 million vehicles per year.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring

  19. Defining Overweight and Obesity

    MedlinePlus

    ... Physical Activity Overweight & Obesity Healthy Weight Breastfeeding Micronutrient Malnutrition State and Local Programs Defining Adult Overweight and ... Physical Activity Overweight & Obesity Healthy Weight Breastfeeding Micronutrient Malnutrition State and Local Programs File Formats Help: How ...

  20. Visualization of pool boiling from complex surfaces with internal tunnels

    NASA Astrophysics Data System (ADS)

    Pastuszko, Robert

    2012-04-01

    The paper presents experimental investigations of boiling heat transfer for a system of connected narrow horizontal and vertical tunnels. These extended surfaces, named narrow tunnel structure (NTS), can be applied to electronic element cooling. The experiments were carried out with ethanol at atmospheric pressure. The tunnel external covers were manufactured out of 0.1 mm thick perforated copper foil (hole diameters 0.5 mm), sintered with the mini-fins, formed on the vertical side of the 10 mm high rectangular fins and horizontal inter-fin surface. Visualization studies were conducted with a transparent structured model of joined narrow tunnels limited with the perforated foil. The visualization investigations aimed to formulate assumptions for the boiling model through distinguishing boiling types and defining all phases of bubble growth.

  1. Tunnel boring waste test plan

    SciTech Connect

    Patricio, J.G. . Rockwell Hanford Operations)

    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.

  2. Introduction to cryogenic wind tunnels

    NASA Technical Reports Server (NTRS)

    Goodyer, M. J.

    1985-01-01

    The background to the evolution of the cryogenic wind tunnel is outlined, with particular reference to the late 60's/early 70's when efforts were begun to re-equip with larger wind tunnels. The problems of providing full scale Reynolds numbers in transonic testing were proving particularly intractible, when the notion of satisfying the needs with the cryogenic tunnel was proposed, and then adopted. The principles and advantages of the cryogenic tunnel are outlined, along with guidance on the coolant needs when this is liquid nitrogen, and with a note on energy recovery. Operational features of the tunnels are introduced with reference to a small low speed tunnel. Finally the outstanding contributions are highlighted of the 0.3-Meter Transonic Cryogenic Tunnel (TCT) at NASA Langley Research Center, and its personnel, to the furtherance of knowledge and confidence in the concept.

  3. Diagnosis of Severe Carpal Tunnel Syndrome Using Nerve Conduction Study and Ultrasonography.

    PubMed

    Fujimoto, Kazuhiro; Kanchiku, Tsukasa; Kido, Kenji; Imajo, Yasuaki; Funaba, Masahiro; Taguchi, Toshihiko

    2015-10-01

    This study investigated the correlation between nerve conduction study and ultrasonographic findings for assessment of the usefulness of ultrasonography in determining carpal tunnel syndrome severity. Hands of adults with carpal tunnel syndrome were assessed using ultrasound and nerve conduction studies and grouped according to median nerve cross-sectional area (CSA). There were significant differences (p < 0.01) in mean median nerve CSA between controls, patients with median sensory nerve conduction velocity ≤40 m/s and patients with absent sensory nerve action potential and between controls, patients with median nerve distal motor latency ≥4.5 ms and patients with absent compound muscle action potentials of the abductor pollicis brevis. This is the first report to define median nerve CSA cutoff values (18 mm(2)) for determining carpal tunnel syndrome severity in patients with absent compound muscle action potentials of the abductor pollicis brevis. Median nerve CSA values below the cutoff values should prompt clinicians to consider other disorders, such as cervical compressive myelopathy.

  4. Defining departmental mission.

    PubMed

    Hartman, M D; Barrow, J A; Sawyer, W R

    1990-02-01

    Mission statements have long been recognized by corporate America as a way to define an enterprise. The necessary business orientation of the health care industry requires that hospitals and hospital departments define their scope of services and reason for existence. The accelerating reprofessionalization affecting departments of pharmacy requires the same. "Improving the quality of patient care" can no longer represent a euphemism for simply reacting to external factors or acting on a whim without clear meaningful intent. Professional departments and hospitals must demonstrate a sense of direction and purpose and be able to justify costs to a budget-conscious management and skeptical public. Mission statements are not substitutes for a clearly defined sense of professional mission. However, well-constructed mission statements contribute to clarity of departmental and professional purpose and effective achievement of goals. PMID:10128549

  5. Defining Risk Drinking

    PubMed Central

    Dawson, Deborah A.

    2011-01-01

    Many efforts to prevent alcohol-related harm are aimed at reducing risk drinking. This article outlines the many conceptual and methodological challenges to defining risk drinking. It summarizes recent evidence regarding associations of various aspects of alcohol consumption with chronic and acute alcohol-related harms, including mortality, morbidity, injury, and alcohol use disorders, and summarizes the study designs most appropriate to defining risk thresholds for these types of harm. In addition, it presents an international overview of low-risk drinking guidelines from more than 20 countries, illustrating the wide range of interpretations of the scientific evidence related to risk drinking. This article also explores the impact of drink size on defining risk drinking and describes variation in what is considered to be a standard drink across populations. Actual and standard drink sizes differ in the United States, and this discrepancy affects definitions of risk drinking and prevention efforts. PMID:22330212

  6. Techniques For Mass Production Of Tunneling Electrodes

    NASA Technical Reports Server (NTRS)

    Kenny, Thomas W.; Podosek, Judith A.; Reynolds, Joseph K.; Rockstad, Howard K.; Vote, Erika C.; Kaiser, William J.

    1993-01-01

    Techniques for mass production of tunneling electrodes developed from silicon-micromachining, lithographic patterning, and related microfabrication processes. Tunneling electrodes named because electrons travel between them by quantum-mechanical tunneling; tunneling electrodes integral parts of tunneling transducer/sensors, which act in conjunction with feedback circuitry to stabilize tunneling currents by maintaining electrode separations of order of 10 Angstrom. Essential parts of scanning tunneling microscopes and related instruments, and used as force and position transducers in novel microscopic accelerometers and infrared detectors.

  7. Defining the Human Microbiome

    PubMed Central

    Ursell, Luke K; Metcalf, Jessica L; Parfrey, Laura Wegener; Knight, Rob

    2012-01-01

    Rapidly developing sequencing methods and analytical techniques are enhancing our ability to understand the human microbiome, and, indeed, how we define the microbiome and its constituents. In this review we highlight recent research that expands our ability to understand the human microbiome on different spatial and temporal scales, including daily timeseries datasets spanning months. Furthermore, we discuss emerging concepts related to defining operational taxonomic units, diversity indices, core versus transient microbiomes and the possibility of enterotypes. Additional advances in sequencing technology and in our understanding of the microbiome will provide exciting prospects for exploiting the microbiota for personalized medicine. PMID:22861806

  8. Surface Wave Imaging to Detect Tunnels

    NASA Astrophysics Data System (ADS)

    Miller, R. D.; Ballard, R. F.; Park, C. B.; Xia, J.

    2002-05-01

    Unauthorized infiltration into the U.S. is possible through the air, from the sea, across the land, and under the ground. Several near-surface geophysical techniques have been evaluated and in certain situations show promise in detecting underground activity related to tunneling. Recently developed acquisition and analysis techniques for multi-channel surface wave imaging has opened the door to a vast number of near-surface applications including anomaly detection and delineation, specifically tunnels. Routine scanning of the subsurface for anomalies unique to tunneling activities using surface waves can be done at relatively high production rates with confident interpretations made by minimally trained technical staff. Acquisition tests have proven that appropriate coupling for accurate recording of surface waves can be established with only pressure contact to the earth's surface, unlike body wave surveying in which coupling is optimized by invasive "planting." Marine streamer technology adapted to land provides near-continuous acquisition of 2-D profiles using pressure-coupled sources and receivers. Once parameters in a particular area have been selected, processing routines can be automated with pattern recognition and differencing routines used to identify potential targets. These nearly fully automated interpretive techniques could be almost real-time with preliminary results available within minutes of data acquisition. This tool is well suited for either initial reconnaissance surveys or differencing of periodic "patrol" surveys. A system using surface wave imaging technology could routinely monitor the shallow subsurface along the U.S. borders to recognize changes in physical earth properties likely related to tunneling. To evaluate the potential of this imaging technology a feasibility study was conducted in an area along the California/Mexico border with two sites in reasonably close proximity: one with a known tunnel and the other with a suspected

  9. Planar Tunneling Spectroscopy of Graphene Nanodevices

    NASA Astrophysics Data System (ADS)

    Wang, Joel I.-Jan; Bretheau, Landry; Pisoni, Riccardo; Watanabe, Kenji; Taniguchi, Takashi; Jarillo-Herrero, Pablo

    2-D Van-der-Waals mesoscopic physics have seen a rapid development in the last 10 years, with new materials each year added to the toolbox. Stacking them like Lego enables the combination of their individual electronic properties. In particular, hexagonal boron nitride, which is an insulator, gives the possibility to perform planar (2-D to 2-D) tunneling spectroscopy within this type of heterostructures. Unlike standard transport measurements, tunneling spectroscopy enables to probe the electronic properties in the energy domain. Moreover, since planar tunneling probes a large area of the system, global quantum features such as quantum Hall effect, superconducting proximity effect or quantum confinement can be investigated. In this talk, we will present implementation of heterostructures consisting of graphene, hexagonal boron nitride, and graphite, fabricated for planar tunneling spectroscopy. In order to reveal the intrinsic properties of materials, the fabrication scheme aims at preserving the pristine nature of the 2-DEGS as well as minimizing the doping introduced by external probes. As a demonstration, measurements of these devices in normal states, high magnetic field environment, and induced superconducting state will be presented.

  10. B-Target Room Tunnel Redesigned

    SciTech Connect

    Esfandiari, Reza; /San Jose State U. /SLAC

    2010-08-25

    Several groups at SLAC National Accelerator Laboratory are currently working on a RF Modulator prototype for a future linear collider known as the International Linear Collider (ILC). The ILC runs using about a 1000 Klystrons which create high power carrier waves for the particle acceleration. Klystrons receive their electrical input power from modulators. In order to move beyond the prototype phase, the laboratory might expand its ground base further down a tunnel located at the End Station B (ESB) in order to house four new Klystron Modulator Test Stations. This area is known as the B-Target Room Tunnel, and the task was to redesign the tunnel layout for the upcoming changes. The project first began by collecting substantial amount of information about the prototyped project, the tunnel and the researchers feedback of what they would like to see in the upcoming design. Subsequent to numerous planning and presentations, one particular design was. Calculations for this design were then performed for the most complex aspects of the project. Based on the results of the calculations, specific sample beams, welds, bolts and materials were chosen for the possible future construction.

  11. Four logic states using two resonant tunnelling diodes

    NASA Astrophysics Data System (ADS)

    van Hoof, C.; Genoe, J.; van Hove, M.; van Rossum, M.; Mertens, R.

    1989-02-01

    Using a series connection of two specially designed resonant tunneling diodes, three negative differential resistance regions, resulting in four possible logic states, were observed. This behavior can be expanded, at least in theory, to n tunneling diodes, resulting in 2 exp n - 1 times switching and 2 exp n logic states. These new devices can be used for analog/digital conversion and multivalued logic or as multistate memory cells using only a minimum in device area.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    Riaz, Asif; Jamil, Syed Muhammad; Asif, Muhammad; Akhtar, Kamran

    2016-03-01

    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.

  14. Possibility of hyperbolic tunneling

    SciTech Connect

    Lobo, Francisco S. N.; Mimoso, Jose P.

    2010-08-15

    Traversable wormholes are primarily useful as 'gedanken experiments' and as a theoretician's probe of the foundations of general relativity. In this work, we analyze the possibility of having tunnels in a hyperbolic spacetime. We obtain exact solutions of static and pseudo-spherically symmetric spacetime tunnels by adding exotic matter to a vacuum solution referred to as a degenerate solution of class A. The physical properties and characteristics of these intriguing solutions are explored, and through the mathematics of embedding it is shown that particular constraints are placed on the shape function, that differ significantly from the Morris-Thorne wormhole. In particular, it is shown that the energy density is always negative, and the radial pressure is positive, at the throat, contrary to the Morris-Thorne counterpart. Specific solutions are also presented by considering several equations of state, and by imposing restricted choices for the shape function or the redshift function.

  15. Uncooled tunneling infrared sensor

    NASA Technical Reports Server (NTRS)

    Kenny, Thomas W. (Inventor); Kaiser, William J. (Inventor); Podosek, Judith A. (Inventor); Vote, Erika C. (Inventor); Rockstad, Howard K. (Inventor); Reynolds, Joseph K. (Inventor)

    1994-01-01

    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 which would otherwise change deflection depending upon incident infrared radiation. The resulting infrared sensor will meet or exceed the performance of all other broadband, uncooled, infrared sensors and can be miniaturized to pixel dimensions smaller than 100 .mu.m. The technology is readily implemented as a small-format linear array suitable for commercial and spacecraft applications.

  16. Tunnel magnetoresistance of diamondoids

    NASA Astrophysics Data System (ADS)

    Matsuura, Yukihito

    2016-10-01

    Tunnel magnetoresistance (TMR) of diamondoids has been predicted by first principles density functional theory. Diamantane was used as a basic molecular proxy for diamondoids because hydrogen atoms in the apical position are easily substituted for a thiol group. The pristine diamantane exhibited a low TMR ratio of 7%, and boron-substitution considerably decreased the TMR ratio. Conversely, nitrogen-substitution enhanced the TMR ratio by up to 20%. Heteroatom-substitution changes the tunneling probabilities by varying the molecular bond lengths. Furthermore, when the spins of the electrodes are parallel, the heteroatoms resulted in transmittance probabilities at an energy range near the Fermi level. Consequently, heteroatom-substitution can control the TMR ratios of diamondoids very well.

  17. On tunneling across horizons

    NASA Astrophysics Data System (ADS)

    Vanzo, L.

    2011-07-01

    The tunneling method for stationary black holes in the Hamilton-Jacobi variant is reconsidered in the light of some critiques that have been moved against. It is shown that once the tunneling trajectories have been correctly identified the method is free from internal inconsistencies, it is manifestly covariant, it allows for the extension to spinning particles and it can even be used without solving the Hamilton-Jacobi equation. These conclusions borrow support on a simple analytic continuation of the classical action of a pointlike particle, made possible by the unique assumption that it should be analytic in the complexified Schwarzschild or Kerr-Newman space-time. A more general version of the Parikh-Wilczek method will also be proposed along these lines.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Light tunneling in clouds.

    PubMed

    Nussenzveig, H Moyses

    2003-03-20

    Solar radiation, traveling outside cloud water droplets, excites sharp resonances and surface waves by tunneling into the droplets. This effect contributes substantially to the total absorption (typically, of the order of 20%) and yields the major contribution to backscattering, producing the meteorological glory. Usual computational practices in atmospheric science misrepresent resonance contributions and cannot be relied on in the assessment of possible anomalies in cloud absorption.

  20. Anterior cruciate ligament tunnel placement.

    PubMed

    Wolf, Brian R; Ramme, Austin J; Britton, Carla L; Amendola, Annunziato

    2014-08-01

    The purpose of this cadaveric study was to analyze variation in anterior cruciate ligament (ACL) tunnel placement between surgeons and the influence of preferred surgical technique and surgeon experience level using three-dimensional (3D) computed tomography (CT). In this study, 12 surgeons drilled ACL tunnels on six cadaveric knees each. Surgeons were divided by experience level and preferred surgical technique (two-incision [TI], medial portal [MP], and transtibial [TT]). ACL tunnel aperture locations were analyzed using 3D CT scans and compared with radiographic ACL footprint criteria. The femoral tunnel location from front to back within the notch demonstrated a range of means of 16% with the TI tunnels the furthest back. A range of means of only 5% was found for femoral tunnel low to high positions by technique. The anterior to posterior tibial tunnel measure demonstrated wider variation than the medial to lateral position. The mean tibial tunnel location drilled by TT surgeons was more posterior than surgeons using the other techniques. Overall, 82% of femoral tunnels and 78% of tibial tunnels met all radiographic measurement criteria. Slight (1-7%) differences in mean tunnel placement on the femur and tibia were found between experienced and new surgeons. The location of the femoral tunnel aperture in the front to back plane relative to the notch roof and the anterior to posterior position on the tibia were the most variable measures. Surgeon experience level did not appear to significantly affect tunnel location. This study provides background information that may be beneficial when evaluating multisurgeon and multicenter collaborative ACL studies.

  1. Defining Faculty Work.

    ERIC Educational Resources Information Center

    Gray, Peter J.; Diamond, Robert M.

    1994-01-01

    A process of planned change is proposed for redefining college faculty work. Legitimate faculty work is defined in broad terms, and information sources and methods for collecting information to support redefinition are identified. The final step in the redefinition process is the development of new mission statements for the institution and its…

  2. Defining Child Abuse.

    ERIC Educational Resources Information Center

    Giovannoni, Jeanne M.; Becerra, Rosina M.

    In seeking to clarify the meaning of the terms "child abuse" and "child neglect" it has been assumed that, like other forms of social deviance, they are socially defined phenomena. Interviews were conducted with those professionals (lawyers, pediatricians, police officers, and social workers) who daily handle the problems of abuse and neglect for…

  3. Defined by Limitations

    ERIC Educational Resources Information Center

    Arriola, Sonya; Murphy, Katy

    2010-01-01

    Undocumented students are a population defined by limitations. Their lack of legal residency and any supporting paperwork (e.g., Social Security number, government issued identification) renders them essentially invisible to the American and state governments. They cannot legally work. In many states, they cannot legally drive. After the age of…

  4. Defining Effective Teaching

    ERIC Educational Resources Information Center

    Layne, L.

    2012-01-01

    The author looks at the meaning of specific terminology commonly used in student surveys: "effective teaching." The research seeks to determine if there is a difference in how "effective teaching" is defined by those taking student surveys and those interpreting the results. To investigate this difference, a sample group of professors and students…

  5. Defining and Assessing Quality.

    ERIC Educational Resources Information Center

    Fincher, Cameron, Ed.

    The seven papers in this monograph focus on defining and assessing quality. The paper are: (1) "Reflections on Design Ideals" (E. Grady Bogue), which addresses some "governing ideals" of collegiate quality; (2) "Between a Rock and a Hard Place: Investment and Quality in Higher Education" (Sven Groennings), which sees the competitive quality of…

  6. On Defining Literacy.

    ERIC Educational Resources Information Center

    Sherritt, Caroline A.

    Defining literacy is a compelling challenge to educators. They generally use three models: instrumental, functional, and empowerment. The latter two approaches, which were increasingly evident in the 1980s, identify literacy by the social functions required in a given context or by the qualities needed for illiterate people to take control of…

  7. Evaluating tunnel kiln performance

    SciTech Connect

    O`Connor, K.R.; Carty, W.M.; Ninos, N.J.

    1997-08-01

    Process improvements in the production of whitewares provide the potential for substantial savings for manufacturers. A typical whiteware manufacturer incurs an annual defective product loss of {approximately}$20 million when accounting for raw materials, energy, labor and waste disposal. Reduction in defective product loss of 1% could result in a savings in excess of $1 million annually. This study was designed to establish benchmarks for two conventional tunnel kilns used to bisque-fire dinnerware at Buffalo China Inc. (Buffalo, NY). The benchmark was established by assessing the current conditions and variability of the two tunnel kilns as a function of the fracture strength of sample bars that were made from production body. Sample bars were fired in multiple locations in both kilns to assess the conditions and variability of firing within each kiln. Comparison of strength results between the two kilns also was assessed. These comparisons were accomplished through applied statistical analysis, wherein significant statistical variations were identified and isolated for both tunnel kilns. The statistical methods and tools used in this analysis are readily accessible to manufacturers, thus allowing implementation of similar analysis, or benchmarking, in-house.

  8. Ferroelectric tunnel memristor.

    PubMed

    Kim, D J; Lu, H; Ryu, S; Bark, C-W; Eom, C-B; Tsymbal, E Y; Gruverman, A

    2012-11-14

    Strong interest in resistive switching phenomena is driven by a possibility to develop electronic devices with novel functional properties not available in conventional systems. Bistable resistive devices are characterized by two resistance states that can be switched by an external voltage. Recently, memristors-electric circuit elements with continuously tunable resistive behavior-have emerged as a new paradigm for nonvolatile memories and adaptive electronic circuit elements. Employment of memristors can radically enhance the computational power and energy efficiency of electronic systems. Most of the existing memristor prototypes involve transition metal oxide resistive layers where conductive filaments formation and/or the interface contact resistance control the memristive behavior. In this paper, we demonstrate a new type of memristor that is based on a ferroelectric tunnel junction, where the tunneling conductance can be tuned in an analogous manner by several orders of magnitude by both the amplitude and the duration of the applied voltage. The ferroelectric tunnel memristors exhibit a reversible hysteretic nonvolatile resistive switching with a resistance ratio of up to 10(5) % at room temperature. The observed memristive behavior is attributed to the field-induced charge redistribution at the ferroelectric/electrode interface, resulting in the modulation of the interface barrier height. PMID:23039785

  9. Ferroelectric tunnel memristor.

    PubMed

    Kim, D J; Lu, H; Ryu, S; Bark, C-W; Eom, C-B; Tsymbal, E Y; Gruverman, A

    2012-11-14

    Strong interest in resistive switching phenomena is driven by a possibility to develop electronic devices with novel functional properties not available in conventional systems. Bistable resistive devices are characterized by two resistance states that can be switched by an external voltage. Recently, memristors-electric circuit elements with continuously tunable resistive behavior-have emerged as a new paradigm for nonvolatile memories and adaptive electronic circuit elements. Employment of memristors can radically enhance the computational power and energy efficiency of electronic systems. Most of the existing memristor prototypes involve transition metal oxide resistive layers where conductive filaments formation and/or the interface contact resistance control the memristive behavior. In this paper, we demonstrate a new type of memristor that is based on a ferroelectric tunnel junction, where the tunneling conductance can be tuned in an analogous manner by several orders of magnitude by both the amplitude and the duration of the applied voltage. The ferroelectric tunnel memristors exhibit a reversible hysteretic nonvolatile resistive switching with a resistance ratio of up to 10(5) % at room temperature. The observed memristive behavior is attributed to the field-induced charge redistribution at the ferroelectric/electrode interface, resulting in the modulation of the interface barrier height.

  10. Analysis of shield tunnel

    NASA Astrophysics Data System (ADS)

    Ding, W. Q.; Yue, Z. Q.; Tham, L. G.; Zhu, H. H.; Lee, C. F.; Hashimoto, T.

    2004-01-01

    This paper proposes a two-dimensional finite element model for the analysis of shield tunnels by taking into account the construction process which is divided into four stages. The soil is assumed to behave as an elasto-plastic medium whereas the shield is simulated by beam-joint discontinuous model in which curved beam elements and joint elements are used to model the segments and joints, respectively. As grout is usually injected to fill the gap between the lining and the soil, the property parameters of the grout are chosen in such a way that they can reflect the state of the grout at each stage. Furthermore, the contact condition between the soil and lining will change with the construction stage, and therefore, different stress-releasing coefficients are used to account for the changes. To assess the accuracy that can be attained by the method in solving practical problems, the shield tunnelling in the No. 7 Subway Line Project in Osaka, Japan, is used as a case history for our study. The numerical results are compared with those measured in the field. The results presented in the paper show that the proposed numerical procedure can be used to effectively estimate the deformation, stresses and moments experienced by the surrounding soils and the concrete lining segments. The analysis and method presented in this paper can be considered to be useful for other subway construction projects involving shield tunnelling in soft soils. Copyright

  11. Resonant Tunneling Spin Pump

    NASA Technical Reports Server (NTRS)

    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.

  12. Tunnelling from black holes and tunnelling into white holes

    NASA Astrophysics Data System (ADS)

    Chatterjee, Bhramar; Ghosh, A.; Mitra, P.

    2008-03-01

    Hawking radiation is nowadays being understood as tunnelling through black hole horizons. Here, the extension of the Hamilton-Jacobi approach to tunnelling for non-rotating and rotating black holes in different non-singular coordinate systems not only confirms this quantum emission from black holes but also reveals the new phenomenon of absorption into white holes by quantum mechanical tunnelling. The rôle of a boundary condition of total absorption or emission is also clarified.

  13. Submucosal tunneling techniques: current perspectives

    PubMed Central

    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. PMID:24741323

  14. 7 CFR 29.9201 - Terms defined.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Terms defined. 29.9201 Section 29.9201 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Tobacco Produced and Marketed in a Quota Area Definitions § 29.9201 Terms defined. As used in this...

  15. 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

    NASA Technical Reports Server (NTRS)

    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.

  16. Relativistic features and time delay of laser-induced tunnel ionization

    NASA Astrophysics Data System (ADS)

    Yakaboylu, Enderalp; Klaiber, Michael; Bauke, Heiko; Hatsagortsyan, Karen Z.; Keitel, Christoph H.

    2013-12-01

    The electron dynamics in the classically forbidden region during relativistic tunnel ionization is investigated. The classical forbidden region in the relativistic regime is identified by defining a gauge-invariant total-energy operator. Introducing position-dependent energy levels inside the tunneling barrier, we demonstrate that the relativistic tunnel ionization can be well described by a one-dimensional intuitive picture. This picture predicts that, in contrast to the well-known nonrelativistic regime, the ionized electron wave packet arises with a momentum shift along the laser's propagation direction. This is compatible with results from a strong-field approximation calculation where the binding potential is assumed to be zero ranged. Further, the tunneling time delay, stemming from Wigner's definition, is investigated for model configurations of tunneling and compared with results obtained from the exact propagator. By adapting Wigner's time delay definition to the ionization process, the tunneling time is investigated in the deep-tunneling and in the near-threshold-tunneling regimes. It is shown that while in the deep-tunneling regime signatures of the tunneling time delay are not measurable at remote distance, they are detectable, however, in the latter regime.

  17. Fabrication of metallic single electron transistors featuring plasma enhanced atomic layer deposition of tunnel barriers

    NASA Astrophysics Data System (ADS)

    Karbasian, Golnaz

    The continuing increase of the device density in integrated circuits (ICs) gives rise to the high level of power that is dissipated per unit area and consequently a high temperature in the circuits. Since temperature affects the performance and reliability of the circuits, minimization of the energy consumption in logic devices is now the center of attention. According to the International Technology Roadmaps for Semiconductors (ITRS), single electron transistors (SETs) hold the promise of achieving the lowest power of any known logic device, as low as 1x10-18 J per switching event. Moreover, SETs are the most sensitive electrometers to date, and are capable of detecting a fraction of an electron charge. Despite their low power consumption and high sensitivity for charge detection, room temperature operation of these devices is quite challenging mainly due to lithographical constraints in fabricating structures with the required dimensions of less than 10 nm. Silicon based SETs have been reported to operate at room temperature. However, they all suffer from significant variation in batch-to-batch performance, low fabrication yield, and temperature-dependent tunnel barrier height. In this project, we explored the fabrication of SETs featuring metal-insulator-metal (MIM) tunnel junctions. While Si-based SETs suffer from undesirable effect of dopants that result in irregularities in the device behavior, in metal-based SETs the device components (tunnel barrier, island, and the leads) are well-defined. Therefore, metal SETs are potentially more predictable in behavior, making them easier to incorporate into circuits, and easier to check against theoretical models. Here, the proposed fabrication method takes advantage of unique properties of chemical mechanical polishing (CMP) and plasma enhanced atomic layer deposition (PEALD). Chemical mechanical polishing provides a path for tuning the dimensions of the tunnel junctions, surpassing the limits imposed by electron beam

  18. Orbiter Model in Wind Tunnel

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Marshall Space Flight Center (MSFC) engineer holding a replica of the proposed Liquid Booster Module, observes the testing of a small Space Shuttle orbiter model at 14 Wind Tunnel at MSFC. 14 Wind Tunnel is a trisonic wind tunnel, which is capable of running subsonic, transonic, and supersonic. It is used to test the integrity of rockets and launch vehicles in launch and reentry environments. The Wind Tunnel was used to test rockets and launch vehicles from the Jupiter C through the Saturn family up to the current Space Shuttle and will be used to test future advanced launch vehicles.

  19. InAs/Si Hetero-Junction Nanotube Tunnel Transistors

    PubMed Central

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

    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. PMID:25923104

  20. View of Water Storage Tank off entrance tunnel. Tunnel at ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Water Storage Tank off entrance tunnel. Tunnel at left of image to Launch Silos - Titan One Missile Complex 2A, .3 miles west of 129 Road and 1.5 miles north of County Line Road, Aurora, Adams County, CO

  1. Full Scale Tunnel (FST)

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Construction of Full Scale Tunnel (FST). In November 1929, Smith DeFrance submitted his recommendations for the general design of the Full Scale Wind Tunnel. The last on his list concerned the division of labor required to build this unusual facility. He believed the job had five parts and described them as follows: 'It is proposed that invitations be sent out for bids on five groups of items. The first would be for one contract on the complete structure; second the same as first, including the erection of the cones but not the fabrication, since this would be more of a shipyard job; third would cover structural steel, cover, sash and doors, but not cones or foundation; fourth, foundations; an fifth, fabrication of cones.' DeFrance's memorandum prompted the NACA to solicit estimates from a large number of companies. Preliminary designs and estimates were prepared and submitted to the Bureau of the Budget and Congress appropriated funds on February 20, 1929. The main construction contract with the J.A. Jones Company of Charlotte, North Carolina was signed one year later on February 12, 1930. It was a peculiar structure as the building's steel framework is visible on the outside of the building. DeFrance described this in NACA TR No. 459: 'The entire equipment is housed in a structure, the outside walls of which serve as the outer walls of the return passages. The over-all length of the tunnel is 434 feet 6 inches, the width 222 feet, and the maximum height 97 feet. The framework is of structural steel....' (pp. 292-293)

  2. Full Scale Tunnel (FST)

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Construction of Full-Scale Tunnel (FST). In November 1929, Smith DeFrance submitted his recommendations for the general design of the Full Scale Wind Tunnel. The last on his list concerned the division of labor required to build this unusual facility. He believed the job had five parts and described them as follows: 'It is proposed that invitations be sent out for bids on five groups of items. The first would be for one contract on the complete structure; second the same as first, including the erection of the cones but not the fabrication, since this would be more of a shipyard job; third would cover structural steel, cover, sash and doors, but not cones or foundation; fourth, foundations; and fifth, fabrication of cones.' DeFrance's memorandum prompted the NACA to solicit estimates from a large number of companies. Preliminary designs and estimates were prepared and submitted to the Bureau of the Budget and Congress appropriated funds on February 20, 1929. The main construction contract with the J.A. Jones Company of Charlotte, North Carolina was signed one year later on February 12, 1930. It was a peculiar structure as the building's steel framework is visible on the outside of the building. DeFrance described this in NACA TR No. 459: 'The entire equipment is housed in a structure, the outside walls of which serve as the outer walls of the return passages. The over-all length of the tunnel is 434 feet 6 inches, the width 222 feet, and the maximum height 97 feet. The framework is of structural steel....' (pp. 292-293).

  3. The Quantum Hydrodynamic Description of Tunneling

    SciTech Connect

    Kendrick, Brian K.

    2012-06-15

    The quantum hydrodynamic approach is based on the de Broglie-Bohm formulation of quantum mechanics. The resulting fluid-like equations of motion describe the flow of probability and an accurate solution to these equations is equivalent to solving the time-dependent Schroedinger equation. Furthermore, the hydrodynamic approach provides new insight into the mechanisms as well as an alternative computational approach for treating tunneling phenomena. New concepts include well-defined 'quantum trajectories', 'quantum potential', and 'quantum force' all of which have classical analogues. The quantum potential and its associated force give rise to all quantum mechanical effects such as zero point energy, tunneling, and interference. A new numerical approach called the Iterative Finite Difference Method (IFDM) will be discussed. The IFDM is used to solve the set of non-linear coupled hydrodynamic equations. It is 2nd-order accurate in both space and time and exhibits exponential convergence with respect to the iteration count. The stability and computational efficiency of the IFDM is significantly improved by using a 'smart' Eulerian grid which has the same computational advantages as a Lagrangian or Arbitrary Lagrangian Eulerian (ALE) grid. The IFDM is also capable of treating anharmonic potentials. Example calculations using the IFDM will be presented which include: a one-dimensional Gaussian wave packet tunneling through an Eckart barrier, a one-dimensional bound-state Morse oscillator, and a two-dimensional (2D) model collinear reaction using an anharmonic potential energy surface. Approximate treatments of the quantum hydrodynamic equations will also be discussed which could allow scaling of the calculations to hundreds of degrees of freedom which is important for treating tunneling phenomena in condensed phase systems.

  4. Nozzle diffuser for use with an open test section of a wind tunnel

    NASA Technical Reports Server (NTRS)

    Barna, P. Stephen (Inventor)

    1993-01-01

    The nozzle diffuser has an inlet in fluid communication with the narrowed inlet of an open test chamber in a conventional wind tunnel. The nozzle diffuser has a passageway extending from its inlet to an outlet in communication with the open test section. The passageway has an internal cross sectional area which increases from its inlet to its outlet and which may be defined by top and bottom isosceles trapezoid walls of a particular flare angle and by isosceles trapezoid side walls of a different flare angle. In addition, a collector having a decreasing internal cross sectional area from inlet to outlet may be provided at the opposite end of the test chamber such that its outlet is in communication with a diffuser located at this outlet.

  5. Supersonic flow development in slotted wind tunnels

    NASA Technical Reports Server (NTRS)

    Ramaswamy, M. A.; Cornette, E. S.

    1980-01-01

    The development of test section slot shapes for achieving smooth supersonic Mach number distribution without overexpansion or waviness has, in the past, been largely an experimentally iterative or 'cutand try' procedure for each wind tunnel. To overcome the obvious disadvantages of time and expense involved in such an experimental approach, a simple analytical method has been developed to predict the supersonic flow development in a two-dimensional slotted tunnel given only the variation of open area ratio with downstream distance and the Mach number corresponding to the plenum static pressure. The well known method of characteristics is used with the constraint that it be compatible with the quadratic cross-flow pressure drop boundary condition at the slotted wall. The predicted results from this method agree remarkably well with the experimental calibration data available for some of the existing facilities. The flow mechanism responsible for causing overexpansion in the centerline Mach number distribution with some slot shapes has been brought to light.

  6. Cryogenic Wind Tunnel Models. Design and Fabrication

    NASA Technical Reports Server (NTRS)

    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. Defining periodontal health

    PubMed Central

    2015-01-01

    Assessment of the periodontium has relied exclusively on a variety of physical measurements (e.g., attachment level, probing depth, bone loss, mobility, recession, degree of inflammation, etc.) in relation to various case definitions of periodontal disease. Periodontal health was often an afterthought and was simply defined as the absence of the signs and symptoms of a periodontal disease. Accordingly, these strict and sometimes disparate definitions of periodontal disease have resulted in an idealistic requirement of a pristine periodontium for periodontal health, which makes us all diseased in one way or another. Furthermore, the consequence of not having a realistic definition of health has resulted in potentially questionable recommendations. The aim of this manuscript was to assess the biological, environmental, sociological, economic, educational and psychological relationships that are germane to constructing a paradigm that defines periodontal health using a modified wellness model. The paradigm includes four cardinal characteristics, i.e., 1) a functional dentition, 2) the painless function of a dentition, 3) the stability of the periodontal attachment apparatus, and 4) the psychological and social well-being of the individual. Finally, strategies and policies that advocate periodontal health were appraised. I'm not sick but I'm not well, and it's a sin to live so well. Flagpole Sitta, Harvey Danger PMID:26390888

  8. Structural changes of the carpal tunnel, median nerve and flexor tendons in MRI before and after endoscopic carpal tunnel release.

    PubMed

    Momose, Toshimitsu; Uchiyama, Shigeharu; Kobayashi, Seneki; Nakagawa, Hiroyuki; Kato, Hiroyuki

    2014-01-01

    The purpose of this study is to investigate the structural changes of the carpal tunnel, median nerve, and flexor tendons in magnetic resonance imaging (MRI) before and after endoscopic carpal tunnel release (ECTR). We studied 36 hands undergoing ECTR. In MRI, the cross-sectional area of the carpal tunnel and the median nerve at the hamate and the pisiform levels were measured. The distance from the volar side of carpal bone to the median nerve or tendons and the volar displacement were measured. In post-operative MRI, the transverse carpal ligament could not be well delineated and the carpal tunnel was significantly enlarged both at the hamate and pisiform levels. The median nerve was enlarged at the hamate level. The median nerve and flexor tendons significantly moved to the volar side. The volar displacement of the median nerve and flexor digitorum superficialis in the long and ring fingers was greater than the other tendons.

  9. H-CANYON AIR EXHAUST TUNNEL INSPECTION VEHICLE DEVELOPMENT

    SciTech Connect

    Minichan, R.; Fogle, R.; Marzolf, A.

    2011-05-24

    The H-Canyon at Savannah River Site is a large concrete structure designed for chemical separation processes of radioactive material. The facility requires a large ventilation system to maintain negative pressure in process areas for radioactive contamination control and personnel protection. The ventilation exhaust is directed through a concrete tunnel under the facility which is approximately five feet wide and 8 feet tall that leads to a sand filter and stack. Acidic vapors in the exhaust have had a degrading effect on the surface of the concrete tunnels. Some areas have been inspected; however, the condition of other areas is unknown. Experience from historical inspections with remote controlled vehicles will be discussed along with the current challenge of inspecting levels below available access points. The area of interest in the exhaust tunnel must be accessed through a 14 X 14 inch concrete plug in the floor of the hot gang valve corridor. The purpose for the inspection is to determine the condition of the inside of the air tunnel and establish if there are any structural concerns. Various landmarks, pipe hangers and exposed rebar are used as reference points for the structural engineers when evaluating the current integrity of the air tunnel.

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

    NASA Technical Reports Server (NTRS)

    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

  11. Early Childhood: Funnels and Tunnels.

    ERIC Educational Resources Information Center

    Fowlkes, Mary Anne

    1985-01-01

    Suggests using funnels and tunnels in combination with water, blocks, transportation toys, and other materials to help teach preschoolers to make predictions. Many examples are included for using funnels to understand properties of liquids and for using tunnels to predict order. (DH)

  12. Defining Giftedness. 1985 Digest.

    ERIC Educational Resources Information Center

    McClellan, Elizabeth

    The digest examines conceptions of giftedness. A brief historical review notes L. Terman's work and impetus for increasingly broadened definitions since the 1940's. The 1969 Marland Report is cited and its definition of giftedness is presented. Current response to that definition's inclusion of six achievement areas (general academic ability,…

  13. Defining Art Appreciation.

    ERIC Educational Resources Information Center

    Seabolt, Betty Oliver

    2001-01-01

    Discusses the differences and goals of four areas: (1) art appreciation; (2) art history; (3) art aesthetics; and (4) art criticism. Offers a definition of art appreciation and information on how the view of art appreciation in education has changed over time. (CMK)

  14. Tunneling magnetic force microscopy

    NASA Technical Reports Server (NTRS)

    Burke, Edward R.; Gomez, Romel D.; Adly, Amr A.; Mayergoyz, Isaak D.

    1993-01-01

    We have developed a powerful new tool for studying the magnetic patterns on magnetic recording media. This was accomplished by modifying a conventional scanning tunneling microscope. The fine-wire probe that is used to image surface topography was replaced with a flexible magnetic probe. Images obtained with these probes reveal both the surface topography and the magnetic structure. We have made a thorough theoretical analysis of the interaction between the probe and the magnetic fields emanating from a typical recorded surface. Quantitative data about the constituent magnetic fields can then be obtained. We have employed these techniques in studies of two of the most important issues of magnetic record: data overwrite and maximizing data-density. These studies have shown: (1) overwritten data can be retrieved under certain conditions; and (2) improvements in data-density will require new magnetic materials. In the course of these studies we have developed new techniques to analyze magnetic fields of recorded media. These studies are both theoretical and experimental and combined with the use of our magnetic force scanning tunneling microscope should lead to further breakthroughs in the field of magnetic recording.

  15. Two tunnels to inflation

    SciTech Connect

    Aguirre, Anthony; Johnson, Matthew C.

    2006-06-15

    We investigate the formation via tunneling of inflating (false-vacuum) bubbles in a true-vacuum background, and the reverse process. Using effective potentials from the junction condition formalism, all true- and false-vacuum bubble solutions with positive interior and exterior cosmological constant, and arbitrary mass are catalogued. We find that tunneling through the same effective potential appears to describe two distinct processes: one in which the initial and final states are separated by a wormhole (the Farhi-Guth-Guven mechanism), and one in which they are either in the same hubble volume or separated by a cosmological horizon. In the zero-mass limit, the first process corresponds to the creation of an inhomogenous universe from nothing, while the second mechanism is equivalent to the nucleation of true- or false-vacuum Coleman-De Luccia bubbles. We compute the probabilities of both mechanisms in the WKB approximation using semiclassical Hamiltonian methods, and find that--assuming both process are allowed--neither mechanism dominates in all regimes.

  16. Carpal tunnel syndrome.

    PubMed

    Chammas, M

    2014-04-01

    Carpal tunnel syndrome is the commonest entrapment neuropathy and is due to combined compression and traction on the median nerve at the wrist. It is often idiopathic. Although spontaneous resolution is possible, the usual natural evolution is slow progression. Diagnosis is mainly clinical depending on symptoms and provocative tests. An electromyogram is recommended preoperatively and in cases of work-related disease. Medical treatment is indicated early on or in cases with no deficit and consists of steroid injection in the canal or a night splint in neutral wrist position. Surgical treatment is by section of the flexor retinaculum and is indicated in resistance to medical treatment, in deficit or acute cases. Mini-invasive techniques such as endoscopic and mini-open approaches to carpal tunnel release with higher learning curves are justified by the shorter functional recovery time compared to classical surgery, but with identical long-term results. The choice depends on the surgeon's preference, patient information, stage of severity, etiology and availability of material. Results are satisfactory in 90% of cases. Nerve recovery depends on the stage of severity as well as general patient factors. Recovery of force takes about 2-3 months after the disappearance of 'pillar pain'. This operation has a benign reputation with a 0.2-0.5% reported neurovascular complication rate.

  17. Defining the mobilome.

    PubMed

    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.

  18. Defining clinical 'workstation'.

    PubMed

    Safran, C

    1994-01-01

    Interest in the physician's workstation has increased, yet often seems to focus on technological issues. At Boston's Beth Israel Hospital, the Center for Clinical Computing includes heavily used clinical workstations. Their evolution over the past 20 years suggests design criteria: the workstation must be patient-centered, the interface must be uniform, and data acquisition must be addressed at a system level. However, it is clinical function that really defines a workstation. The workstation should do the following: display patient information rapidly and flexibly; assist with administrative tasks; facilitate communication; and provide four important types of decision support: access to literature, access to databases, clinical calculation, and 'synthetic vision,' or different views of patient data. The solutions to our healthcare problems are not in 'workboxes' we can buy, but in creative approaches we can imagine. We need a patient-centered infrastructure and a reduced workload for the clinician-perhaps a 'worklesstation'. PMID:8125637

  19. Tunneling in thin MOS structures

    NASA Technical Reports Server (NTRS)

    Maserjian, J.

    1974-01-01

    Recent results on tunneling in thin MOS structures are described. Thermally grown SiO2 films in the thickness range of 22-40 A have been shown to be effectively uniform on an atomic scale and exhibit an extremely abrupt oxide-silicon interface. Resonant reflections are observed at this interface for Fowler-Nordheim tunneling and are shown to agree with the exact theory for a trapezoidal barrier. Tunneling at lower fields is consistent with elastic tunneling into the silicon direct conduction band and, at still lower fields, inelastic tunneling into the indirect conduction band. Approximate dispersion relations are obtained over portions of the silicon-dioxide energy gap and conduction band.

  20. Carpal tunnel syndrome and acromegaly.

    PubMed

    Baum, H; Lüdecke, D K; Herrmann, H D

    1986-01-01

    50 patients with acromegaly and carpal tunnel syndrome have been examined electrophysiologically before and after transnasal operation of the pituitary adenoma. 32 of the 50 patients (64%) had symptoms of carpal tunnel syndrome. 13 of them had neurological deficits. 28 of the examined patients had pathological neurographical findings only. About 1 week post-operatively DL was decreased in 43%; in 10 out of 13 patients with neurological deficits DL decreased. GH was normalized in 80% and reduced to 5-10 micrograms/l in a further 10%. The investigation did not show whether the carpal tunnel syndrome only depended on a GH increase or on other factors also such as e.g., on the duration of symptoms or tissue changes. None of the patients had the transversal carpal ligament operated on. The coincidence between acromegaly and carpal tunnel syndrome was 64%. In 3 cases the carpal tunnel syndrome was the leading sign to the diagnosis of acromegaly.

  1. The separation of the Hartland Formation and Ravenswood Granodiorite from the Fordham Gneiss at Cameron's Line in the New York City area

    USGS Publications Warehouse

    Baskerville, C.A.; Mose, D.G.

    1989-01-01

    Recent study of the rocks in City Water Tunnel Number 3 between Roosevelt Island and beneath 34th Street and the 63rd Street subway-rail tunnels at 41st Avenue in Long Island City, as well as study of drill core from other sites in western Queens, establishes that this area of New York City is underlain by the Ravenswood Granodiorite and the Hartland Formation. The Fordham Gneiss does not appear east of the East River at these sites. Cameron's Line can be traced down the east side of the East River, as learned from observations in the tunnels, separating the Middle Proterozoic Fordham Gneiss to the west from the Cambrian and Ordovician Hartland Formation and related Ravenswood Granodiorite to the east. The older, adequately defined, Ravenswood Granodiorite, Hartland Formation, and the Fordham Gneiss, are the rock units that make up the poorly defined Brooklyn gneiss or Brooklyn Injection Gneiss and thus appropriately should supercede these later classifications. -from Authors

  2. NASA Glenn Wind Tunnel Model Systems Criteria

    NASA Technical Reports Server (NTRS)

    Soeder, Ronald H.; Roeder, James W.; Stark, David E.; Linne, Alan A.

    2004-01-01

    This report describes criteria for the design, analysis, quality assurance, and documentation of models that are to be tested in the wind tunnel facilities at the NASA Glenn Research Center. This report presents two methods for computing model allowable stresses on the basis of the yield stress or ultimate stress, and it defines project procedures to test models in the NASA Glenn aeropropulsion facilities. Both customer-furnished and in-house model systems are discussed. The functions of the facility personnel and customers are defined. The format for the pretest meetings, safety permit process, and model reviews are outlined. The format for the model systems report (a requirement for each model that is to be tested at NASA Glenn) is described, the engineers responsible for developing the model systems report are listed, and the timetable for its delivery to the project engineer is given.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Idiopathic Carpal Tunnel Syndrome: Evaluation of the Depth of the Carpal Tunnel by Ultrasonography.

    PubMed

    Elsaman, Ahmed Mohammed Mahrous Yousif; Thabit, Mohamed Nasreldin; Radwan, Ahmed Roshdy Al-Agamy; Ohrndorf, Sarah

    2015-11-01

    The objective of the work described here was to evaluate the depth of the carpal tunnel (DCT) in patients with idiopathic carpal tunnel syndrome (CTS) and healthy volunteers by ultrasonography (US), through measurement of the distance from the flexor retinaculum to the surface of the capitate bone at the carpal tunnel outlet, and compare it with other ultrasonographic and electrophysiologic parameters in CTS. The study was conducted in 60 non-diabetic patients with idiopathic carpal tunnel syndrome (unilateral n = 37, bilateral n = 23) evidenced by electrophysiologic diagnosis according to the criteria of the American Association of Electrodiagnostic Medicine (AAEM). Furthermore, 40 hands from 20 healthy volunteers were examined. Median nerve cross-sectional area (CSA); flattening ratio (FR), the ratio of the length to the width of the median nerve; and DCT at the canal outlet were measured for all participants. The mean age was 35.6 ± 9.48 y. The female-to-male ratio was 47:13 in the CTS patients. The sensitivity and specificity were 82% and 95% for CSA, 75% and 60% for FR and 75% and 87.5% for DCT, respectively. Differences between patients and healthy controls were significant for all three parameters, greatest for DCT, followed by CSA and then FR. We conclude that DCT increased in CTS and this new parameter is comparable in sensitivity and specificity to CSA and FR. DCT increased independently of the cause of the CTS (decrease in size of canal or increase in contents).

  6. Defining the Anthropocene

    NASA Astrophysics Data System (ADS)

    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

  7. Electromagnetics for Detecting Shallow Tunnels

    NASA Astrophysics Data System (ADS)

    Won, I.

    2006-05-01

    Detecting tunnels by geophysical means, even very shallow ones, has been difficult, to say the least. Despite heavy R&D funding from the military since the early 70s, geophysicists have not produced tools that are simple and practical enough to meet the military needs. The initial interest and R&D funding on the subject perhaps started with the Vietcong tunnels in the 60s. Tunnels in the Korean DMZ, first found in the mid 70s, sharply escalated the R&D spending. During the 90s, covert tunnels along the US-Mexico border have kept the topic alive but at a minimal funding level. Most recent interest appears to be in the terrorism-related shallow tunnels, more or less anywhere in the regions of conflict. Despite the longstanding effort in the geophysical community under heavy public funding, there is a dearth of success stories where geophysicists can actually claim to have found hitherto unknown tunnels. For instance, geophysics has not discovered a single tunnel in Vietnam or in Korea! All tunnels across the Korean DMZ were found from human intelligence. The same is true to all illicit tunnels found along the southwestern border. The tunnels under discussion are clandestine, which implies that the people who built them do not wish others to succeed in finding them. The place around the tunnel, therefore, may not be the friendliest venue for surveyors to linger around. The situation requires tools that are fast, little noticeable, and hardly intrusive. Many geophysical sensors that require ground contacts, such as geophones and electrodes that are connected by a myriad of cables, may not be ideal in this situation. On the other hand, a sensor that can be carried by vehicle without stopping, and is nothing obviously noticeable to bystanders, could be much more acceptable. Working at unfriendly environment also requires forgoing our usual practices where we collect data leisurely and make pretty maps later. To be useful, geophysical tools must be able to process

  8. Tunneling electroresistance effect in ferroelectric tunnel junctions at the nanoscale.

    PubMed

    Gruverman, A; Wu, D; Lu, H; Wang, Y; Jang, H W; Folkman, C M; Zhuravlev, M Ye; Felker, D; Rzchowski, M; Eom, C-B; Tsymbal, E Y

    2009-10-01

    Using a set of scanning probe microscopy techniques, we demonstrate the reproducible tunneling electroresistance effect on nanometer-thick epitaxial BaTiO(3) single-crystalline thin films on SrRuO(3) bottom electrodes. Correlation between ferroelectric and electronic transport properties is established by direct nanoscale visualization and control of polarization and tunneling current. The obtained results show a change in resistance by about 2 orders of magnitude upon polarization reversal on a lateral scale of 20 nm at room temperature. These results are promising for employing ferroelectric tunnel junctions in nonvolatile memory and logic devices. PMID:19697939

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

    NASA Astrophysics Data System (ADS)

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

    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/Al2O3/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.

  10. Wind tunnel technology for the development of future commercial aircraft

    NASA Technical Reports Server (NTRS)

    Szodruch, J.

    1986-01-01

    Requirements for new technologies in the area of civil aircraft design are mainly related to the high cost involved in the purchase of modern, fuel saving aircraft. A second important factor is the long term rise in the price of fuel. The demonstration of the benefits of new technologies, as far as these are related to aerodynamics, will,for the foreseeable future, still be based on wind tunnel measurements. Theoretical computation methods are very successfully used in design work, wing optimization, and an estimation of the Reynolds number effect. However, wind tunnel tests are still needed to verify the feasibility of the considered concepts. Along with other costs, the cost for the wind tunnel tests needed for the development of an aircraft is steadily increasing. The present investigation is concerned with the effect of numerical aerodynamics and civil aircraft technology on the development of wind tunnels. Attention is given to the requirements for the wind tunnel, investigative methods, measurement technology, models, and the relation between wind tunnel experiments and theoretical methods.

  11. [Carpal tunnel syndrome revealed by digital ulcerations caused by arterial vasospasm].

    PubMed

    Léger, O; Lavallé, F

    2005-02-01

    Carpal tunnel syndrome presenting as a trophic disorder in the hand is unusual. We report the case of a 66 year old man in whom nerve conduction tests confirmed compression of the median nerve in the carpal tunnel, and vasospasm in the corresponding area was demonstrated by arteriography for, we believe, the first time. Simple decompression of the carpal tunnel brought about total recovery. The mechanism of the autonomic disorders found in carpal tunnel syndrome remains controversial. The clinical case that we report objectively demonstrates the vasospasm caused by the compression of the autonomic fibres of the median nerve.

  12. Reducing Wind Tunnel Data Requirements Using Neural Networks

    NASA Technical Reports Server (NTRS)

    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.

  13. Defining The Other Solitude

    PubMed Central

    Gruson, Valerie; Bates, Joanna

    1990-01-01

    The changing content of urban-based family practice needs to be redefined so that appropriate family medicine training programs can be planned to meet the primary care health needs of Canada's urban-based population. Although the core content of family practice is common to both rural and urban areas, each requires specific skills and attitudes dictated by differences in patient characteristics, disease incidence, physician expectations, and professional contexts. A challenge for the future is the development of both rural-based and urban-based streams of family medicine training that will unite rather than divide the profesiion. PMID:21233947

  14. SUBSONIC WIND TUNNEL PERFORMANCE ANALYSIS SOFTWARE

    NASA Technical Reports Server (NTRS)

    Eckert, W. T.

    1994-01-01

    This program was developed as an aid in the design and analysis of subsonic wind tunnels. It brings together and refines previously scattered and over-simplified techniques used for the design and loss prediction of the components of subsonic wind tunnels. It implements a system of equations for determining the total pressure losses and provides general guidelines for the design of diffusers, contractions, corners and the inlets and exits of non-return tunnels. The algorithms used in the program are applicable to compressible flow through most closed- or open-throated, single-, double- or non-return wind tunnels or ducts. A comparison between calculated performance and that actually achieved by several existing facilities produced generally good agreement. Any system through which air is flowing which involves turns, fans, contractions etc. (e.g., an HVAC system) may benefit from analysis using this software. This program is an update of ARC-11138 which includes PC compatibility and an improved user interface. The method of loss analysis used by the program is a synthesis of theoretical and empirical techniques. Generally, the algorithms used are those which have been substantiated by experimental test. The basic flow-state parameters used by the program are determined from input information about the reference control section and the test section. These parameters were derived from standard relationships for compressible flow. The local flow conditions, including Mach number, Reynolds number and friction coefficient are determined for each end of each component or section. The loss in total pressure caused by each section is calculated in a form non-dimensionalized by local dynamic pressure. The individual losses are based on the nature of the section, local flow conditions and input geometry and parameter information. The loss forms for typical wind tunnel sections considered by the program include: constant area ducts, open throat ducts, contractions, constant

  15. Tunneling spectra of graphene on copper unraveled.

    PubMed

    Zhang, Xin; Stradi, Daniele; Liu, Lei; Luo, Hong; Brandbyge, Mads; Gu, Gong

    2016-06-22

    Scanning tunneling spectroscopy is often employed to study two-dimensional (2D) materials on conductive growth substrates, in order to gain information on the electronic structures of the 2D material-substrate systems, which can lead to insight into 2D material-substrate interactions, growth 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 assignment of the spectral features. In addition, we have discovered an O-Cu superstructure that has never been observed before.

  16. Respiratory risks in tunnel construction workers.

    PubMed

    Arcangeli, G; Cupelli, V; Montalti, M; Pristera, M; Baldasseroni, A; Giuliano, G

    2004-01-01

    Respiratory diseases are frequent in tunnel construction workers. A group of 144 subjects randomly selected from the population of 2516 workers engaged in the construction of the railway tunnel under the Appennine Mountains, from Bologna to Firenze was investigated. A group of 69 males comparable for age, living area and habits was studied as a control group. Assessment of air pollutants (NO, NO2, SO2, total dust, silica %) was carried out by means of fixed monitoring stations as well as personal monitors. All the subjects included in the study were examined with a standardised protocol which included physical examination, lung function tests (before and after shift work) and a questionnaire to college respiratory symptoms. Low concentrations of environmental pollutants were evidenced. Significantly lower values of FEV1 and PEF were determined in the worker group pared to controls. A significant decrease in respiratory parameters was shown after shift work. Variables capable of influencing the decrease in parameters include smoking habits, work activity, presence of cough and expectoration, period of the year (spirometries resulted worse in the winter time). Significantly lower values of FEV1 and PEF were evidenced in the workers compared to controls. In spite of the present low work environmental exposure conditions, some physiologic parameters appear altered in tunnel construction workers. This may depend on a variety of noxious agents present in the working environment.

  17. Variable-Density Tunnel

    NASA Technical Reports Server (NTRS)

    1921-01-01

    The outside pressure shell for the Variable-Density Tunnel (VDT). The shell, or 'tank' as it was called, was built in the Newport News Shipyard and traveled by barge to Langley. The tank could withstand a working pressure of 21 atmospheres. Elton Miller described it in NACA TR No. 227 (pp. 411-412): 'It is built of steel plates lapped and riveted according to the usual practice in steam boiler construction, although, because of the size of the tank and the high working pressure, the construction is unusually heavy. There is a cylindrical body portion of 2-1/8 inch (53.98 millimeters) steel plate with hemispherical ends 1-1/4 inches (31.75 millimeters) in thickness.'

  18. 3. VIEW OF WIND TUNNEL, LOOKING NORTHWEST (1991). WrightPatterson ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW OF WIND TUNNEL, LOOKING NORTHWEST (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  19. 6. CLOSEUP VIEW OF TENFOOT WIND TUNNEL (1991). WrightPatterson ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. CLOSE-UP VIEW OF TEN-FOOT WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  20. 9. INTERIOR VIEW OF WIND TUNNEL (1991). WrightPatterson Air ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. INTERIOR VIEW OF WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  1. 11. INTERIOR VIEW OF WIND TUNNEL (1991). WrightPatterson Air ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. INTERIOR VIEW OF WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  2. 10. INTERIOR VIEW OF WIND TUNNEL (1991). WrightPatterson Air ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. INTERIOR VIEW OF WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  3. 8. NORTH VIEW ALONG SIDE OF TUNNEL (1991). WrightPatterson ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. NORTH VIEW ALONG SIDE OF TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  4. 7. SOUTH VIEW ALONG SIDE OF TUNNEL (1991). WrightPatterson ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. SOUTH VIEW ALONG SIDE OF TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  5. Promoting and inhibiting tunneling via nuclear motions.

    PubMed

    Császár, Attila G; Furtenbacher, Tibor

    2016-01-14

    Accurate, experimental rotational-vibrational energy levels determined via the MARVEL (Measured Active Rotational-Vibrational Energy Levels) algorithm and published recently for the symmetric-top (14)NH3 molecule in J. Quant. Spectrosc. Radiat. Transfer, 2015, 116, 117-130 are analyzed to unravel the promoting and inhibiting effects of vibrations and rotations on the tunneling splittings of the corresponding symmetric (s) and antisymmetric (a) rovibrational energy level pairs. The experimental transition data useful from the point of view of the present analysis cover the range 0.7-7000 cm(-1), sufficiently detailed rovibrational energy sets worth analyzing are available for 20 vibrational bands. The highest J value, where J stands for the rotational quantum number, within the experimental dataset employed is 30. Coupling of the "umbrella" motion of (14)NH3 with other vibrational degrees of freedom has only a minor effect on the a-s tunneling splitting characterizing the ground vibrational state, 0.79436(70) cm(-1). In the majority of the cases rotation around the C3 axis increases, while rotation around the two perpendicular axes decreases the tunneling splittings. For example, for the pair of vibrational ground states, 0(+) and 0(-), the tunneling splitting basically disappears at around J = 25 for the (J,K) = (J,1) states, where K = |k| is the usual quantum number characterizing the projection of the rotational angular momentum on the principal axis. The tunneling splittings, defined as energy differences E(a) - E(s) of corresponding energy level pairs, as a function of J and K show a very regular behavior for the ground state (GS) and the nν2 bands. For the other bands investigated exceptions from a regular behavior do occur, especially for bands characterized by degenerate vibrations, and occasionally the data available are not sufficient to arrive at definitive conclusions. The most irregular behavior is observed for rotational states characterized by the k

  6. Mars Surface Tunnel Element Concept

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle A.; Jefferies, Sharon; Howe, A. Scott; Howard, Robert; Mary, Natalie; Watson, Judith; Lewis, Ruthan

    2016-01-01

    When the first human visitors on Mars prepare to return to Earth, they will have to comply with stringent planetary protection requirements. Apollo Program experience warns that opening an EVA hatch directly to the surface will bring dust into the ascent vehicle. To prevent inadvertent return of potential Martian contaminants to Earth, careful consideration must be given to the way in which crew ingress their Mars Ascent Vehicle (MAV). For architectures involving more than one surface element-such as an ascent vehicle and a pressurized rover or surface habitat-a retractable tunnel that eliminates extravehicular activity (EVA) ingress is an attractive solution. Beyond addressing the immediate MAV access issue, a reusable tunnel may be useful for other surface applications, such as rover to habitat transfer, once its primary mission is complete. A National Aeronautics and Space Administration (NASA) team is studying the optimal balance between surface tunnel functionality, mass, and stowed volume as part of the Evolvable Mars Campaign (EMC). The study team began by identifying the minimum set of functional requirements needed for the tunnel to perform its primary mission, as this would presumably be the simplest design, with the lowest mass and volume. This Minimum Functional Tunnel then becomes a baseline against which various tunnel design concepts and potential alternatives can be traded, and aids in assessing the mass penalty of increased functionality. Preliminary analysis indicates that the mass of a single-mission tunnel is about 237 kg, not including mass growth allowance.

  7. Effects of worker size on the dynamics of fire ant tunnel construction

    PubMed Central

    Gravish, Nick; Garcia, Mateo; Mazouchova, Nicole; Levy, Laura; Umbanhowar, Paul B.; Goodisman, Michael A. D.; Goldman, Daniel I.

    2012-01-01

    Social insects work together to complete tasks. However, different individuals within a colony may vary in task proficiency. We investigated if fire ant (Solenopsis invicta) worker body size influenced the ability to construct tunnels—a key component of subterranean nests. We monitored excavation by worker groups in a substrate of small wetted glass particles in quasi-two-dimensional arenas. Morphological and network features of the tunnel system were measured. Total tunnel area did not differ significantly between groups of large and small workers, although the tunnel area of control sized workers was significantly larger than that of large workers. Moreover, large workers created wider but shorter tunnels, with slower growth rate of tunnel number. However, edge–vertex scaling and degree distribution of the tunnel network were similar across all treatments. In all cases, the amount of excavated material was correlated with the number of active workers. Our study reveals that morphological features of excavated tunnels show modest variation when constructed by workers of varying sizes, but topological features associated with the tunnel network are conserved. These results suggest that important behavioural aspects of tunnel construction—and thus nest building—are similar among morphologically distinct members of fire ant societies. PMID:22915634

  8. Spin tunneling in conducting oxides

    SciTech Connect

    Bratkovsky, A.

    1998-12-31

    Different tunneling mechanisms in conventional and half-metallic ferromagnetic tunnel junctions are analyzed within the same general method. Direct tunneling is compared with impurity-assisted, surface state assisted, and inelastic contributions to a tunneling magnetoresistance (TMR). Theoretically calculated direct tunneling in iron group systems leads to about a 30% change in resistance, which is close to experimentally observed values. It is shown that the larger observed values of the TMR might be a result of tunneling involving surface polarized states. The authors find that tunneling via resonant defect states in the barrier radically decreases the TMR (down to 4% with Fe-based electrodes), and a resonant tunnel diode structure would give a TMR of about 8%. With regards to inelastic tunneling, magnons and phonons exhibit opposite effects: one-magnon emission generally results in spin mixing and, consequently, reduces the TMR, whereas phonons are shown to enhance the TMR. The inclusion of both magnons and phonons reasonably explains an unusually bias dependence of the TMR. The model presented here is applied qualitatively to half-metallics with 100% spin polarization, where one-magnon processes are suppressed and the change in resistance in the absence of spin-mixing on impurities may be arbitrarily large. Even in the case of imperfect magnetic configurations, the resistance change can be a few 1,000%. Examples of half-metallic systems are CrO{sub 2}/TiO{sub 2} and CrO{sub 2}/RuO{sub 2}, and an account of their peculiar band structures is presented. The implications and relation of these systems to CMR materials, which are nearly half-metallic, are discussed.

  9. Dual-Element Tunneling Accelerometer

    NASA Technical Reports Server (NTRS)

    Kaiser, William J.; Kenny, Thomas W.; Rockstad, Howard K.; Reynolds, Joseph K.

    1994-01-01

    Improved micromachined tunneling accelerometer contains two deflecting transducer elements: One an elastically supported proof mass having relatively low resonant frequency; other cantilever tunneling transducer that tracks displacement of proof mass and has relatively high resonant frequency ({sup a} 10 kHz). Deflection voltage generated by circuit like described in "Wideband Feedback Circuit for Tunneling Sensor" (NPO-18866). Accelerometers of this type suited for underwater acoustic measurements, detecting vibrations associated with malfunctions in vehicles, detecting seismic signals, monitoring and controlling vibrations in structures, and other applications.

  10. Vibrationally enhanced tunneling as a mechanism for enzymatic hydrogen transfer.

    PubMed Central

    Bruno, W J; Bialek, W

    1992-01-01

    We present a theory of enzymatic hydrogen transfer in which hydrogen tunneling is mediated by thermal fluctuations of the enzyme's active site. These fluctuations greatly increase the tunneling rate by shortening the distance the hydrogen must tunnel. The average tunneling distance is shown to decrease when heavier isotopes are substituted for the hydrogen or when the temperature is increased, leading to kinetic isotope effects (KIEs)--defined as the factor by which the reaction slows down when isotopically substituted substrates are used--that need be no larger than KIEs for nontunneling mechanisms. Within this theory we derive a simple KIE expression for vibrationally enhanced ground state tunneling that is able to fit the data for the bovine serum amine oxidase (BSAO) system, correctly predicting the large temperature dependence of the KIEs. Because the KIEs in this theory can resemble those for nontunneling dynamics, distinguishing the two possibilities requires careful measurements over a range of temperatures, as has been done for BSAO. PMID:1420907

  11. Langley Spin Tunnel - Free Flight Tunnel - and models

    NASA Technical Reports Server (NTRS)

    1939-01-01

    Model shop for NACA Spin Tunnel and Free Flight Tunnel. Dynamically and geometrically accurate models with movable control surfaces are made here by men whose training as toy model makers is producing valuable results. The models are used for study of the stability and control of aircraft which is an essential basis for safety. Photograph published in Winds of Change, a 75th Anniversary NASA publication (page 10), by James Schultz.

  12. Tunneling progress on the Yucca Mountain Project

    SciTech Connect

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

    1996-06-01

    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.

  13. Real-Time Visualization of Ultrasonography Guided Cubital Tunnel Injection: A Cadaveric Study

    PubMed Central

    Kim, Jae Min; Kim, Min-Wook

    2012-01-01

    Objective To describe an ultrasonography-guided technique for cubital tunnel injection. Method The ulnar nerves from 12 elbows of 6 adult cadavers were scanned, and the cross-sectional areas of the ulnar nerves, cubital tunnel inlets and outlets were measured by using ultrasonography. All elbows were dissected after an ultrasonography-guided dye injection at the inlet of the cubital tunnel. The dissectors evaluated the spread of dye and the coloration of the nerve and remeasured the cross-sectional areas of the cubital tunnel inlets and outlets. Results After a real-time visualization of an ultrasonography-guided injection, the ulnar nerves were seperated from the medial groove for the ulnar nerve. All the ulnar nerves of the cadavers were successfully colored with the dye, from the inlet to oulet of the cubital tunnel. The post-injection cross-sectional areas were significantly larger than the pre-injection cross-sectional areas. No significant differences were detected in the post-injection cross-sectional areas of the cubital tunnel outlet and the ulnar nerve as compared with the pre-injection areas. Conclusion Clinicians should consider real-time visualization of ultrasonography for guided injection around the ulnar nerve at the inlet of the cubital tunnel. PMID:22977775

  14. TWINTAN: A program for transonic wall interference assessment in two-dimensional wind tunnels

    NASA Technical Reports Server (NTRS)

    Kemp, W. B., Jr.

    1980-01-01

    A method for assessing the wall interference in transonic two dimensional wind tunnel test was developed and implemented in a computer program. The method involves three successive solutions of the transonic small disturbance potential equation to define the wind tunnel flow, the perturbation attriburable to the model, and the equivalent free air flow around the model. Input includes pressure distributions on the model and along the top and bottom tunnel walls which are used as boundary conditions for the wind tunnel flow. The wall induced perturbation fields is determined as the difference between the perturbation in the tunnel flow solution and the perturbation attributable to the model. The methodology used in the program is described and detailed descriptions of the computer program input and output are presented. Input and output for a sample case are given.

  15. Flatback airfoil wind tunnel experiment.

    SciTech Connect

    Mayda, Edward A.; van Dam, C.P.; Chao, David D.; Berg, Dale E.

    2008-04-01

    A computational fluid dynamics study of thick wind turbine section shapes in the test section of the UC Davis wind tunnel at a chord Reynolds number of one million is presented. The goals of this study are to validate standard wind tunnel wall corrections for high solid blockage conditions and to reaffirm the favorable effect of a blunt trailing edge or flatback on the performance characteristics of a representative thick airfoil shape prior to building the wind tunnel models and conducting the experiment. The numerical simulations prove the standard wind tunnel corrections to be largely valid for the proposed test of 40% maximum thickness to chord ratio airfoils at a solid blockage ratio of 10%. Comparison of the computed lift characteristics of a sharp trailing edge baseline airfoil and derived flatback airfoils reaffirms the earlier observed trend of reduced sensitivity to surface contamination with increasing trailing edge thickness.

  16. Tunnel construction for a desertron

    SciTech Connect

    Hinterberger, H.; Huson, F.R.

    1983-03-27

    The tunnel in this model of construction is 3-1/2 feet wide by 5 feet high. It is assumed that the tunnel contains a rail system and guidance system for: (1) An enclosed car used for transport of 2 people and some tools. (2) A magnet mover. This robot could pick up a magnet and transport it at about 10 miles per hour. (3) An alignment robot. The alignment robot would intercept E.M. waves (microwaves, lasers) to determine its position in the tunnel. Then workers could come along inside the tunnel hoop and nail it together and to the floor. The trench would then be back-filled with a 1 foot berm on top. A rail system would be installed and a support stand for the magnet.

  17. Icing Research Tunnel Test Section

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Icing Research Tunnel Test Section NASA technician measuring ice deposits on an airfoil after completing a test at the Lewis Research Center. NASA Lewis is now known as John H. Glean Research Center at Lewis Field.

  18. Tunneling Plasmonics in Bilayer Graphene.

    PubMed

    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.

  19. Intercellular communication in malignant pleural mesothelioma: properties of tunneling nanotubes

    PubMed Central

    Ady, Justin W.; Desir, Snider; Thayanithy, Venugopal; Vogel, Rachel I.; Moreira, André L.; Downey, Robert J.; Fong, Yuman; Manova-Todorova, Katia; Moore, Malcolm A. S.; Lou, Emil

    2014-01-01

    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 changes in TnT length over time in comparison to cell proliferation. 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. PMID:25400582

  20. Flow quality studies of the NASA Lewis Research Center Icing Research Tunnel

    NASA Technical Reports Server (NTRS)

    Arrington, E. Allen; Pickett, Mark T.; Sheldon, David W.

    1994-01-01

    A series of studies have been conducted to determine the flow quality in the NASA Lewis Icing Research Tunnel. The primary purpose of these studies was to document airflow characteristics, including flow angularity, in the test section and tunnel loop. A vertically mounted rake was used to survey total and static pressure and two components of flow angle at three axial stations within the test section (test section inlet, test plane, and test section exit; 15 survey stations total). This information will be used to develop methods of improving the aerodynamic and icing characteristics within the test section. The data from surveys made in the tunnel loop were used to determine areas where overall tunnel flow quality and efficiency can be improved. A separate report documents similar flow quality surveys conducted in the diffuser section of the Icing Research Tunnel. The flow quality studies were conducted at several locations around the tunnel loop. Pressure, velocity, and flow angularity measurements were made by using both fixed and translating probes. Although surveys were made throughout the tunnel loop, emphasis was placed on the test section and tunnel areas directly upstream of the test section (settling chamber, bellmouth, and cooler). Flow visualization, by video recording smoke and tuft patterns, was also used during these studies. A great deal of flow visualization work was conducted in the area of the drive fan. Information gathered there will be used to improve the flow quality upstream and downstream of the fan.

  1. Guidelines for tunneling in enzymes

    PubMed Central

    Moser, Christopher C.; Ross Anderson, J. L.; Dutton, P. Leslie

    2010-01-01

    Summary Here we extend the engineering descriptions of simple, single-electron-tunneling chains common in oxidoreductases to quantify sequential oxidation-reduction rates of two-or-more electron cofactors and substrates. We identify when nicotinamides may be vulnerable to radical mediated oxidation-reduction and merge electron-tunneling expressions with the chemical rate expressions of Eyring. The work provides guidelines for the construction of new artificial oxidoreductases inspired by Nature but adopting independent design and redox engineering. PMID:20460101

  2. Quantum tunneling in flux compactifications

    NASA Astrophysics Data System (ADS)

    Blanco-Pillado, Jose J.; Schwartz-Perlov, Delia; Vilenkin, Alexander

    2009-12-01

    We identify instantons representing vacuum decay in a 6-dimensional toy model for string theory flux compactifications, with the two extra dimensions compactified on a sphere. We evaluate the instanton action for tunneling between different flux vacua, as well as for the decompactification decay channel. The bubbles resulting from flux tunneling have an unusual structure. They are bounded by two-dimensional branes, which are localized in the extra dimensions. This has important implications for bubble collisions.

  3. Lightning tests and analyses of tunnel bond straps and shielded cables on the Space Shuttle solid rocket booster

    NASA Technical Reports Server (NTRS)

    Druen, William M.

    1993-01-01

    The purposes of the tests and analyses described in this report are as follows: (1) determine the lightning current survivability of five alternative changed designs of the bond straps which electrically bond the solid rocket booster (SRB) systems tunnel to the solid rocket motor (SRM) case; (2) determine the amount of reduction in induced voltages on operational flight (OF) tunnel cables obtained by a modified design of tunnel bond straps (both tunnel cover-to-cover and cover-to-motor case); (3) determine the contribution of coupling to the OF tunnel cables by ground electrical and instrumentation (GEI) cables which enter the systems tunnel from unshielded areas on the surfaces of the motor case; and (4) develop a model (based on test data) and calculate the voltage levels at electronic 'black boxes' connected to the OF cables that run in the systems tunnel.

  4. CARPAL TUNNEL SYNDROME AND WORK

    PubMed Central

    Newington, Lisa; Harris, E Clare; Walker-Bone, Karen

    2016-01-01

    INTRODUCTION AND SCOPE Carpal tunnel syndrome (CTS) is the most common peripheral nerve entrapment syndrome and frequently presents in working-aged adults. Its mild form causes ‘nuisance’ symptoms including dysaesthesia and nocturnal waking. At its most severe however it can significantly impair motor function and weaken pinch grip. This review will discuss the anatomy of the carpal tunnel and the clinical presentation of the syndrome as well as the classification and diagnosis of the condition. Carpal tunnel syndrome has a profile of well-established risk factors including individual factors and predisposing co-morbidities, which will be briefly discussed. However, there is a growing body of evidence for an association between carpal tunnel syndrome and various occupational factors, which will also be discussed. Management of carpal tunnel syndrome, conservative and surgical will be described. Finally, we will discuss the issue of safe return to work post carpal tunnel release surgery and the lack of evidence-based guidelines. PMID:26612240

  5. 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

    NASA Technical Reports Server (NTRS)

    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.

  6. Full Scale Wind Tunnel and Seaplane Tow Channel

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Construction progress, aerials of East Area. L5169: Langley's seaplane towing facility (right) and the Full Scale Tunnel (left) were photographed in November of 1930. Photograph published in Winds of Change, 75th Anniversary NASA publication (page 39), by James Schultz.

  7. Modifications to the 4x7 meter tunnel for acoustic research: Engineering feasibility study

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The NASA-Langley Research Center 4 x 7 Meter Low Speed Wind Tunnel is currently being used for low speed aerodynamics, V/STOL aerodynamics and, to a limited extent, rotorcraft noise research. The deficiencies of this wind tunnel for both aerodynamics and aeroacoustics research have been recognized for some time. Modifications to the wind tunnel are being made to improve the test section flow quality and to update the model cart systems. A further modification of the 4 x 7 Meter Wind Tunnel to permit rotorcraft model acoustics research has been proposed. As a precursor to the design of the proposed modifications, NASA is conducted both in-house and contracted studies to define the acoustic environment within the wind tunnel and to provide recommendations or the reduction of the wind tunnel background noise to a level acceptable to acoustics researchers. One of these studies by an acoustics consultant, has produced the primary reference documents that define the wind tunnel noise sources and outline recommended solutions.

  8. Effect of stripe height on the critical current density of spin-torque noise in a tunneling magnetoresistive read head with a low resistance area product below 1.0 Ω μm{sup 2}

    SciTech Connect

    Endo, Yasushi Fan, Peng; Yamaguchi, Masahiro

    2015-05-07

    To understand the spin-torque effect on the noise in tunneling magnetoresistive (TMR) read heads, the GHz range noise spectra of TMR read heads with a narrow track width (w = 36 nm), and various stripe heights (h) are investigated as a function of the external magnetic field (H{sub ex}) and dc bias current density (j). The strong noise peak intensity depends on both H{sub ex} and j, indicating that the spin-torque affects the thermal mag-noise under a positive (negative) j for a positive (negative) H{sub ex}, regardless of h in the TMR heads. Due to the increased shape anisotropy, the critical current density (j{sub c}), where the non-thermal fluctuation noise originates from the spin-torque, increases markedly as the head dimension is reduced, and the maximum value of j{sub c} is approximately +1.5 × 10{sup 12} A/m{sup 2} for a head with w = 36 nm and h = 15 nm. These results demonstrate that the non-thermal fluctuation noise originating from the spin-torque in the TMR head can be suppressed in the current density range below 10{sup 12} A/m{sup 2}, as the head dimension is reduced and the shape anisotropy is increased.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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.

  11. Hawking Radiation of the Charged Particle via Tunneling from the Kaluza-Klein Black Hole

    NASA Astrophysics Data System (ADS)

    Pu, Jin; Han, Yan

    2016-08-01

    In this paper, by applying the Lagrangian analysis on the action, we first redefine the geodesic equation of the charged massive particle. Then, basing on the new definition of the geodesic equation, we revisit the Hawking radiation of the charged massive particle via tunneling from the event horizon of the Kaluza-Klein black hole. In our treatment, the geodesic equation of the charged massive particle is defined uniformly with that of the massless particle, which overcomes the shortcomings of its previous definition, and is more suitable for the tunneling mechanism. The highlight of our work is a new and important development for the Parikh-Wilczek's tunneling method.

  12. TWINTN4: A program for transonic four-wall interference assessment in two-dimensional wind tunnels

    NASA Technical Reports Server (NTRS)

    Kemp, W. B., Jr.

    1984-01-01

    A method for assessing the wall interference in transonic two-dimensional wind tunnel tests including the effects of the tunnel sidewall boundary layer was developed and implemented in a computer program named TWINTN4. The method involves three successive solutions of the transonic small disturbance potential equation to define the wind tunnel flow, the equivalent free air flow around the model, and the perturbation attributable to the model. Required input includes pressure distributions on the model and along the top and bottom tunnel walls which are used as boundary conditions for the wind tunnel flow. The wall-induced perturbation field is determined as the difference between the perturbation in the tunnel flow solution and the perturbation attributable to the model. The methodology used in the program is described and detailed descriptions of the computer program input and output are presented. Input and output for a sample case are given.

  13. Tunneling in strongly correlated materials

    NASA Astrophysics Data System (ADS)

    Maltseva, Marianna

    Tunneling studies of strongly correlated materials provide information about the nature of electronic correlations, which is vital for investigation of emergent materials at the microscopic level. In particular, scanning tunneling spectroscopy/microscopy (STS/STM) studies have made major contributions to understanding cuprate superconductors (66), yet there is a sense that huge STM data arrays contain much more precious information to be extracted and analyzed. One of the most pressing questions in the field is how to improve the data analysis, so as to extract more information from STM data. A dominant trend in STM data analysis has been to interpret the data within a particular microscopic model, while using only basic data analysis tools. To decrease the reliance of the STM data interpretation on particular microscopic models, further advances in data analysis methods are necessary. In Chapter 2 of this Thesis, we discuss how one can extract information about the phase of the order parameter from STM data. We show that symmetrized and anti-symmetrized correlators of local density of states give rise to observable coherence factor effects. In Chapter 3, we apply this framework to analyze the recent scanning tunneling experiments on an underdoped cuprate superconductor Ca2-xNaxCuO2Cl2 by T. Hanaguri et al. (60). In Chapter 4, we propose a model for nodal quasiparticle scattering in a disordered vortex lattice. Recently, scanning tunneling studies of a Kondo lattice material URu2Si2 became possible (117). If it proves possible to apply scanning tunneling spectroscopy to Kondo lattice materials, then remarkable new opportunities in the ongoing investigation may emerge. In Chapter 5, we examine the effect of co-tunneling to develop a theory of tunneling into a Kondo lattice. We find that the interference between the direct tunneling and the co-tunneling channels leads to a novel asymmetric lineshape, which has two peaks and a gap. The presence of the peaks suggests

  14. Wind tunnel studies of Martian aeolian processes

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Iversen, J. D.; Pollack, J. B.; Udovich, N.; White, B.

    1973-01-01

    Preliminary results are reported of an investigation which involves wind tunnel simulations, geologic field studies, theoretical model studies, and analyses of Mariner 9 imagery. Threshold speed experiments were conducted for particles ranging in specific gravity from 1.3 to 11.35 and diameter from 10.2 micron to 1290 micron to verify and better define Bagnold's (1941) expressions for grain movement, particularly for low particle Reynolds numbers and to study the effects of aerodynamic lift and surface roughness. Wind tunnel simulations were conducted to determine the flow field over raised rim craters and associated zones of deposition and erosion. A horseshoe vortex forms around the crater, resulting in two axial velocity maxima in the lee of the crater which cause a zone of preferential erosion in the wake of the crater. Reverse flow direction occurs on the floor of the crater. The result is a distinct pattern of erosion and deposition which is similar to some martian craters and which indicates that some dark zones around Martian craters are erosional and some light zones are depositional.

  15. Parallel Quantum Circuit in a Tunnel Junction

    NASA Astrophysics Data System (ADS)

    Faizy Namarvar, Omid; Dridi, Ghassen; Joachim, Christian; GNS theory Group Team

    In between 2 metallic nanopads, adding identical and independent electron transfer paths in parallel increases the electronic effective coupling between the 2 nanopads through the quantum circuit defined by those paths. Measuring this increase of effective coupling using the tunnelling current intensity can lead for example for 2 paths in parallel to the now standard G =G1 +G2 + 2√{G1 .G2 } conductance superposition law (1). This is only valid for the tunnelling regime (2). For large electronic coupling to the nanopads (or at resonance), G can saturate and even decay as a function of the number of parallel paths added in the quantum circuit (3). We provide here the explanation of this phenomenon: the measurement of the effective Rabi oscillation frequency using the current intensity is constrained by the normalization principle of quantum mechanics. This limits the quantum conductance G for example to go when there is only one channel per metallic nanopads. This ef fect has important consequences for the design of Boolean logic gates at the atomic scale using atomic scale or intramolecular circuits. References: This has the financial support by European PAMS project.

  16. Report Tunneling Cost Reduction Study prepared for Fermilab

    SciTech Connect

    Not Available

    1999-07-16

    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

  17. Chamber leakage effects on measured gas concentrations during contained demilitarization tests at NTS X-Tunnel

    SciTech Connect

    Christopher R. Shadix; Joel Lipkin

    1999-11-01

    A series of contained explosive detonation and propellant burn experiments was conducted during 1996 and 1997 using a specially constructed, large, underground chamber located in the X-tunnel complex at Area 25 of the Nevada Test Site (NTS).

  18. In-vehicle nitrogen dioxide concentrations in road tunnels

    NASA Astrophysics Data System (ADS)

    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.

  19. Mitigation of shock waves in a cylindrical tunnel by foam

    NASA Astrophysics Data System (ADS)

    Fondaw, Grant W.

    1993-03-01

    The effectiveness of foam linings in mitigating shock waves in tunnels is investigated. A polyurethane foam liner of varying density, crush strength, and thickness was modeled inside a 1 meter radius tunnel and an explosion of 1.25 kg of plastic explosive was simulated. Using CTH, an Eulerian-Lagrangian hydrodynamics code from Sandia National Laboratories, the overpressures were computed and compared graphically to determine the effect of varying each foam parameter. The walls of the tunnel consisted of a perfectly reflecting boundary, and in some cases, a foam liner. Low density foam provided the most shock attenuation, with a 20 cm thick layer of 90% void 0.1265 g/cm(sup 3) foam reducing the shock overpressure by 70% at 50 meters. The effects of foam thickness on the shock pressure varied with the distance from the explosion. The thicker foams raised the initial pressure near the explosion due to constriction of the tunnel area. However, the thicker layers reduced the shock faster. Varying the crush strength of the foam from 1 atm to 3 atm overpressure did not affect its ability to mitigate shock propagation in the tunnel. The results strongly suggest that foam can mitigate shock waves significantly.

  20. Treatment of tunnel wash water and implications for its disposal.

    PubMed

    Hallberg, M; Renman, G; Byman, L; Svenstam, G; Norling, M

    2014-01-01

    The use of road tunnels in urban areas creates water pollution problems, since the tunnels must be frequently cleaned for traffic safety reasons. The washing generates extensive volumes of highly polluted water, for example, more than fivefold higher concentrations of suspended solids compared to highway runoff. The pollutants in the wash water have an affinity for particulate material, so sedimentation should be a viable treatment option. In this study, 12 in situ sedimentation trials were carried out on tunnel wash water, with and without addition of chemical flocculent. Initial suspended solids concentration ranged from 804 to 9,690 mg/L. With sedimentation times of less than 24 hours and use of a chemical flocculent, it was possible to reach low concentrations of suspended solids (<15 mg/L), PAH (<0.1 μg/L), As (<1.0 μg/L), Cd (<0.05 μg/L), Hg (<0.02 μg/L), Fe (<200 μg/L), Ni (<8 μg/L), Pb (<0.5 μg/L), Zn (<60 μg/L) and Cr (<8 μg/L). Acute Microtox(®) toxicity, mainly attributed to detergents used for the tunnel wash, decreased significantly at low suspended solids concentrations after sedimentation using a flocculent. The tunnel wash water did not inhibit nitrification. The treated water should be suitable for discharge into recipient waters or a wastewater treatment plant.

  1. Ferromagnetic tunnel contacts to graphene: Contact resistance and spin signal

    SciTech Connect

    Cubukcu, M.; Laczkowski, P.; Vergnaud, C.; Marty, A.; Attané, J.-P.; Notin, L.; Vila, L. Jamet, M.; Martin, M.-B.; Seneor, P.; Anane, A.; Deranlot, C.; Fert, A.; Auffret, S.; Ducruet, C.

    2015-02-28

    We report spin transport in CVD graphene-based lateral spin valves using different magnetic contacts. We compared the spin signal amplitude measured on devices where the cobalt layer is directly in contact with the graphene to the one obtained using tunnel contacts. Although a sizeable spin signal (up to ∼2 Ω) is obtained with direct contacts, the signal is strongly enhanced (∼400 Ω) by inserting a tunnel barrier. In addition, we studied the resistance-area product (R.A) of a variety of contacts on CVD graphene. In particular, we compared the R.A products of alumina and magnesium oxide tunnel barriers grown by sputtering deposition of aluminum or magnesium and subsequent natural oxidation under pure oxygen atmosphere or by plasma. When using an alumina tunnel barrier on CVD graphene, the R.A product is high and exhibits a large dispersion. This dispersion can be highly reduced by using a magnesium oxide tunnel barrier, as for the R.A value. This study gives insight in the material quest for reproducible and efficient spin injection in CVD graphene.

  2. Characterization of aluminum oxide tunnel barriers by combining transport measurements and transmission electron microscopy imaging

    SciTech Connect

    Aref, T.; Averin, A.; Nguyend, H. Q.; Pekola, J. P.; Dijken, S. van; Yao, L. D.; Ferring, A.; Koberidze, M.; Nieminen, R. M.

    2014-08-21

    We present two approaches for studying the uniformity of a tunnel barrier. The first approach is based on measuring single-electron and two-electron tunneling in a hybrid single-electron transistor. Our measurements indicate that the effective area of a conduction channel is about one order of magnitude larger than predicted by theoretical calculations. With the second method, transmission electron microscopy, we demonstrate that variations in the barrier thickness are a plausible explanation for the larger effective area and an enhancement of higher order tunneling processes.

  3. Conversion of Non-Tunneled to Tunneled Hemodialysis Catheters

    SciTech Connect

    Ha, Thuong G. Van Fimmen, Derek; Han, Laura; Funaki, Brian S.; Santeler, Scott; Lorenz, Jonathan

    2007-04-15

    Purpose. To determine the safety and efficacy of conversion of non-tunneled (temporary) catheters to tunneled catheters in hemodialysis patients. Methods. A retrospective review of 112 consecutive conversions in 111 patients was performed over a period of 4 years. Fourteen patients were lost to follow-up. The remaining 97 patients had clinical follow-up. Temporary catheters were converted to tunneled catheters utilizing the same internal jugular venotomy sites and a modified over-the-wire technique with use of a peel-away sheath . Follow-up clinical data were reviewed. Results. Technical success was achieved in all 112 procedures. None of the 97 patients with follow-up suffered early infection within 30 days. The total number of follow-up catheter days was 13,659 (range 2-790). Cases of confirmed and suspected bacteremia requiring catheter removal occurred at a frequency of 0.10 per 100 catheter days. Suspected catheter infection treated with antibiotics but not requiring catheter intervention occurred at a frequency of 0.04 per 100 catheter days. Frequency of all suspected or confirmed infections was 0.14 per 100 catheter days. Catheter interventions as a result of poor blood flow, inadvertent removal, catheter fracture, or kinking occurred at a rate of 0.18 per 100 catheter days. Life table analysis revealed primary patency rates of 86%, 64%, and 39% at 30 days, 90 days, and 180 days, respectively. Conclusion. Conversion of temporary catheters to tunneled catheters using the pre-existing venotomy sites is safe and has low rates of infection and malfunction. These rates are comparable to previously published rates for tunneled catheters placed de novo and tunneled catheter exchanges.

  4. Risk factors for carpal tunnel syndrome in a general population.

    PubMed Central

    Nordstrom, D L; Vierkant, R A; DeStefano, F; Layde, P M

    1997-01-01

    OBJECTIVE: To determine the individual, physical, and psychosocial risk factors for carpal tunnel syndrome in a general population. METHODS: Population based case-control study in Marshfield epidemiological study area in Wisconsin, USA. Cases were men and women aged 18-69 with newly diagnosed carpal tunnel syndrome (n = 206 (83.1%) of 248 eligible). Controls were a random sample of residents of the study area who had no history of diagnosed carpal tunnel syndrome (n = 211 (81.5%) of 259 eligible). Cases and controls were matched by age. Telephone interviews and reviews of medical records obtained height and weight, medical history, average daily hours of exposure to selected physical and organisational work factors, and self ratings on psychosocial work scales. RESULTS: In the final logistic regression model, five work and three non-work variables were associated with risk of carpal tunnel syndrome, after adjusting for age. For each one unit of increase in body mass index (kg/m2), risk increased 8% (odds ratio (OR) 1.08; 95% confidence interval (95% CI) 1.03 to 1.14). Having a previous musculoskeletal condition was positively associated with carpal tunnel syndrome (OR 2.54; 95% CI 1.03 to 6.23). People reporting the least influence at work had 2.86 times the risk (95% CI, 1.10 to 7.14) than those with the most influence at work. CONCLUSIONS: Carpal tunnel syndrome is a work related disease, although some important measures of occupational exposure, including keyboard use, were not risk factors in this general population study. The mechanism whereby a weight gain of about six pounds increases the risk of disease 8% requires explanation. PMID:9404321

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

    USGS Publications Warehouse

    Walton-Day, K.; Poeter, E.

    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 (??18O and ??2H) 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

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

    USGS Publications Warehouse

    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

  7. Ultrasound instrumentation for the 7 inch Mach seven tunnel

    NASA Technical Reports Server (NTRS)

    Mazel, D. S.; Mielke, R. R.

    1985-01-01

    The use of an Apple II+ microcomputer to collect data during the operation of the 7 inch Mach Seven Tunnel is discussed. A method by which the contamination of liquid oxygen is monitored with sound speed techniques is investigated. The electrical equivalent of a transducer bonded to a high pressure fill plug is studied. The three areas are briefly explained and data gathered for each area are presented.

  8. Lithographically defined few-electron silicon quantum dots based on a silicon-on-insulator substrate

    SciTech Connect

    Horibe, Kosuke; Oda, Shunri; Kodera, Tetsuo

    2015-02-23

    Silicon quantum dot (QD) devices with a proximal single-electron transistor (SET) charge sensor have been fabricated in a metal-oxide-semiconductor structure based on a silicon-on-insulator substrate. The charge state of the QDs was clearly read out using the charge sensor via the SET current. The lithographically defined small QDs enabled clear observation of the few-electron regime of a single QD and a double QD by charge sensing. Tunnel coupling on tunnel barriers of the QDs can be controlled by tuning the top-gate voltages, which can be used for manipulation of the spin quantum bit via exchange interaction between tunnel-coupled QDs. The lithographically defined silicon QD device reported here is technologically simple and does not require electrical gates to create QD confinement potentials, which is advantageous for the integration of complicated constructs such as multiple QD structures with SET charge sensors for the purpose of spin-based quantum computing.

  9. Other cryogenic wind tunnel projects

    NASA Technical Reports Server (NTRS)

    Kilgore, Robert A.

    1989-01-01

    The first cryogenic tunnel was built in 1972. Since then, many cryogenic wind-tunnel projects were started at aeronautical research centers around the world. Some of the more significant of these projects are described which are not covered by other lecturers at this Special Course. Described are cryogenic wind-tunnel projects in five countries: China (Chinese Aeronautical Research and Development Center); England (College of Aeronautics at Cranfield, and Royal Aerospace Establishment-Bedford); Japan (National Aerospace Laboratory, University of Tsukuba, and National Defense Academy); United States (Douglas Aircraft Co., University of Illinois at Urbana-Champaign and NASA Langley); and U.S.S.R. (Central Aero-Hydronamics Institute (TsAGI), Institute of Theoretical and Applied Mechanics (ITAM), and Physical-Mechanical Institute at Kharkov (PMI-K).

  10. Other Cryogenic Wind Tunnel Projects

    NASA Technical Reports Server (NTRS)

    Kilgore, Robert A.

    1997-01-01

    The first cryogenic tunnel was built at the NASA Langley Research Center in 1972. Since then, many cryogenic wind-tunnels have been built at aeronautical research centers around the world. In this lecture some of the more interesting and significant of these projects that have not been covered by other lecturers at this Special Course are described. In this lecture authors describe cryogenic wind-tunnel projects at research centers in four countries: China (Chinese Aeronautical Research and Development Center); England (College of Aeronautics at Cranfield, and Defence Research Agency - Bedford); Japan (National Aerospace Laboratory, University of Tsukuba, and National Defense Academy); and United States (Douglas Aircraft Co., University of Illinois at Urbana-Champaign, and NASA Langley).

  11. Carpal tunnel syndrome and work.

    PubMed

    Newington, Lisa; Harris, E Clare; Walker-Bone, Karen

    2015-06-01

    Carpal tunnel syndrome (CTS) is the most common peripheral nerve entrapment syndrome, and it frequently presents in working-aged adults. Its mild form causes 'nuisance' symptoms including dysaesthesia and nocturnal waking. At its most severe, CTS can significantly impair motor function and weaken pinch grip. This review discusses the anatomy of the carpal tunnel and the clinical presentation of the syndrome as well as the classification and diagnosis of the condition. CTS has a profile of well-established risk factors including individual factors and predisposing co-morbidities, which are briefly discussed. There is a growing body of evidence for an association between CTS and various occupational factors, which is also explored. Management of CTS, conservative and surgical, is described. Finally, the issue of safe return to work post carpal tunnel release surgery and the lack of evidence-based guidelines are discussed.

  12. Advanced recovery systems wind tunnel test report

    NASA Technical Reports Server (NTRS)

    Geiger, R. H.; Wailes, W. K.

    1990-01-01

    Pioneer Aerospace Corporation (PAC) conducted parafoil wind tunnel testing in the NASA-Ames 80 by 120 test sections of the National Full-Scale Aerodynamic Complex, Moffett Field, CA. The investigation was conducted to determine the aerodynamic characteristics of two scale ram air wings in support of air drop testing and full scale development of Advanced Recovery Systems for the Next Generation Space Transportation System. Two models were tested during this investigation. Both the primary test article, a 1/9 geometric scale model with wing area of 1200 square feet and secondary test article, a 1/36 geometric scale model with wing area of 300 square feet, had an aspect ratio of 3. The test results show that both models were statically stable about a model reference point at angles of attack from 2 to 10 degrees. The maximum lift-drag ratio varied between 2.9 and 2.4 for increasing wing loading.

  13. A Numerical Comparison of Symmetric and Asymmetric Supersonic Wind Tunnels

    NASA Astrophysics Data System (ADS)

    Clark, Kylen D.

    Supersonic wind tunnels are a vital aspect to the aerospace industry. Both the design and testing processes of different aerospace components often include and depend upon utilization of supersonic test facilities. Engine inlets, wing shapes, and body aerodynamics, to name a few, are aspects of aircraft that are frequently subjected to supersonic conditions in use, and thus often require supersonic wind tunnel testing. There is a need for reliable and repeatable supersonic test facilities in order to help create these vital components. The option of building and using asymmetric supersonic converging-diverging nozzles may be appealing due in part to lower construction costs. There is a need, however, to investigate the differences, if any, in the flow characteristics and performance of asymmetric type supersonic wind tunnels in comparison to symmetric due to the fact that asymmetric configurations of CD nozzle are not as common. A computational fluid dynamics (CFD) study has been conducted on an existing University of Michigan (UM) asymmetric supersonic wind tunnel geometry in order to study the effects of asymmetry on supersonic wind tunnel performance. Simulations were made on both the existing asymmetrical tunnel geometry and two axisymmetric reflections (of differing aspect ratio) of that original tunnel geometry. The Reynolds Averaged Navier Stokes equations are solved via NASAs OVERFLOW code to model flow through these configurations. In this way, information has been gleaned on the effects of asymmetry on supersonic wind tunnel performance. Shock boundary layer interactions are paid particular attention since the test section integrity is greatly dependent upon these interactions. Boundary layer and overall flow characteristics are studied. The RANS study presented in this document shows that the UM asymmetric wind tunnel/nozzle configuration is not as well suited to producing uniform test section flow as that of a symmetric configuration, specifically one

  14. Tunnelling in van der Waals heterostructures

    NASA Astrophysics Data System (ADS)

    Mishchenko, Artem; Novoselov, Kostya; Geim, Andre; Eaves, Laurence; Falko, Vladimir

    When graphene and other conductive two-dimensional (2D) materials are separated by an atomically thin insulating 2D crystal, quantum mechanical tunnelling leads to appreciable current between two 2D conductors due to the overlap of their wavefunctions. These tunnel devices demonstrate interesting physics and potential for applications: such effects as resonant tunnelling, negative differential conductance, light emission and detection have already been demonstrated. In this presentation we will outline the current status and perspectives of tunnelling transistors based on 2D materials assembled into van der Waals heterostructures. Particularly, we will present results on mono- and bilayer graphene tunnelling, tunnelling in 2D crystal-based quantum wells, and tunnelling in superconducting 2D materials. Such effects as momentum and chirality conservation, phonon- and impurity-assisted tunnelling will also be discussed. Finally, we will ponder the implications of discovered effects for practical applications.

  15. Computational multiqubit tunnelling in programmable quantum annealers.

    PubMed

    Boixo, Sergio; Smelyanskiy, Vadim N; Shabani, Alireza; Isakov, Sergei V; Dykman, Mark; Denchev, Vasil S; Amin, Mohammad H; Smirnov, Anatoly Yu; Mohseni, Masoud; Neven, Hartmut

    2016-01-07

    Quantum tunnelling is a phenomenon in which a quantum state traverses energy barriers higher than the energy of the state itself. Quantum tunnelling has been hypothesized as an advantageous physical resource for optimization in quantum annealing. However, computational multiqubit tunnelling has not yet been observed, and a theory of co-tunnelling under high- and low-frequency noises is lacking. Here we show that 8-qubit tunnelling plays a computational role in a currently available programmable quantum annealer. We devise a probe for tunnelling, a computational primitive where classical paths are trapped in a false minimum. In support of the design of quantum annealers we develop a nonperturbative theory of open quantum dynamics under realistic noise characteristics. This theory accurately predicts the rate of many-body dissipative quantum tunnelling subject to the polaron effect. Furthermore, we experimentally demonstrate that quantum tunnelling outperforms thermal hopping along classical paths for problems with up to 200 qubits containing the computational primitive.

  16. Computational multiqubit tunnelling in programmable quantum annealers

    PubMed Central

    Boixo, Sergio; Smelyanskiy, Vadim N.; Shabani, Alireza; Isakov, Sergei V.; Dykman, Mark; Denchev, Vasil S.; Amin, Mohammad H.; Smirnov, Anatoly Yu; Mohseni, Masoud; Neven, Hartmut

    2016-01-01

    Quantum tunnelling is a phenomenon in which a quantum state traverses energy barriers higher than the energy of the state itself. Quantum tunnelling has been hypothesized as an advantageous physical resource for optimization in quantum annealing. However, computational multiqubit tunnelling has not yet been observed, and a theory of co-tunnelling under high- and low-frequency noises is lacking. Here we show that 8-qubit tunnelling plays a computational role in a currently available programmable quantum annealer. We devise a probe for tunnelling, a computational primitive where classical paths are trapped in a false minimum. In support of the design of quantum annealers we develop a nonperturbative theory of open quantum dynamics under realistic noise characteristics. This theory accurately predicts the rate of many-body dissipative quantum tunnelling subject to the polaron effect. Furthermore, we experimentally demonstrate that quantum tunnelling outperforms thermal hopping along classical paths for problems with up to 200 qubits containing the computational primitive. PMID:26739797

  17. Computational multiqubit tunnelling in programmable quantum annealers

    NASA Astrophysics Data System (ADS)

    Boixo, Sergio; Smelyanskiy, Vadim N.; Shabani, Alireza; Isakov, Sergei V.; Dykman, Mark; Denchev, Vasil S.; Amin, Mohammad H.; Smirnov, Anatoly Yu; Mohseni, Masoud; Neven, Hartmut

    2016-01-01

    Quantum tunnelling is a phenomenon in which a quantum state traverses energy barriers higher than the energy of the state itself. Quantum tunnelling has been hypothesized as an advantageous physical resource for optimization in quantum annealing. However, computational multiqubit tunnelling has not yet been observed, and a theory of co-tunnelling under high- and low-frequency noises is lacking. Here we show that 8-qubit tunnelling plays a computational role in a currently available programmable quantum annealer. We devise a probe for tunnelling, a computational primitive where classical paths are trapped in a false minimum. In support of the design of quantum annealers we develop a nonperturbative theory of open quantum dynamics under realistic noise characteristics. This theory accurately predicts the rate of many-body dissipative quantum tunnelling subject to the polaron effect. Furthermore, we experimentally demonstrate that quantum tunnelling outperforms thermal hopping along classical paths for problems with up to 200 qubits containing the computational primitive.

  18. Molecular series-tunneling junctions.

    PubMed

    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. PMID:25871745

  19. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low temperatures shall...

  20. 49 CFR 177.810 - Vehicular tunnels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Vehicular tunnels. 177.810 Section 177.810... Information and Regulations § 177.810 Vehicular tunnels. Except as regards Class 7 (radioactive) materials... through any urban vehicular tunnel used for mass transportation....

  1. 43 CFR 3832.40 - Tunnel sites.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Tunnel sites. 3832.40 Section 3832.40..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LOCATING MINING CLAIMS OR SITES Tunnel Sites § 3832.40 Tunnel sites....

  2. 43 CFR 3832.40 - Tunnel sites.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Tunnel sites. 3832.40 Section 3832.40..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LOCATING MINING CLAIMS OR SITES Tunnel Sites § 3832.40 Tunnel sites....

  3. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low temperatures shall...

  4. 49 CFR 177.810 - Vehicular tunnels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Vehicular tunnels. 177.810 Section 177.810... Information and Regulations § 177.810 Vehicular tunnels. Except as regards Class 7 (radioactive) materials... through any urban vehicular tunnel used for mass transportation....

  5. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low temperatures shall...

  6. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low temperatures shall...

  7. 43 CFR 3832.40 - Tunnel sites.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Tunnel sites. 3832.40 Section 3832.40..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LOCATING MINING CLAIMS OR SITES Tunnel Sites § 3832.40 Tunnel sites....

  8. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low temperatures shall...

  9. 49 CFR 177.810 - Vehicular tunnels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Vehicular tunnels. 177.810 Section 177.810... Vehicular tunnels. Except as regards Class 7 (radioactive) materials, nothing contained in parts 170-189 of... tunnel used for mass transportation....

  10. 43 CFR 3832.40 - Tunnel sites.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Tunnel sites. 3832.40 Section 3832.40..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LOCATING MINING CLAIMS OR SITES Tunnel Sites § 3832.40 Tunnel sites....

  11. Study of Surface Displacements on Tunnelling under Buildings Using 3DEC Numerical Modelling.

    PubMed

    Rebello, Nalini; Sastry, V R; Shivashankar, R

    2014-01-01

    Underground structures at shallow depths are often constructed for metro lines, either in loose or dense layered soils. Tunnelling in urban areas is predominantly under surface structures and on tunnelling, innumerable changes in the form of distortion take place in strata surrounding the tunnel. Extent of displacement/damage to buildings or the tunnel-soil structure interaction depends on the type of building and nature of strata. Effect on displacements has been less studied in granular soils compared to other types of soils like clays. In this paper, parametric studies are conducted to find the displacements at surface, in granular soil conditions, due to varying building storeys and building eccentricities from the tunnel centre line. Effect of presence of geosynthetic layer under footings is further studied. Prior to the parametric studies, validity of the model used is checked with field data available for a stretch of tunnel in South India. Results of simulation studies reveal that inclusion of building reduces displacements at the surface in the dense strata. In very dense strata, the displacements increase as compared to the case without a building. As the centre of the building moves away from the tunnel centre line, settlement above the tunnel matches displacements in the case without building. Applicability of 3DEC software is checked with respect to the present study. PMID:27437472

  12. Study of Surface Displacements on Tunnelling under Buildings Using 3DEC Numerical Modelling

    PubMed Central

    Rebello, Nalini; Sastry, V. R.

    2014-01-01

    Underground structures at shallow depths are often constructed for metro lines, either in loose or dense layered soils. Tunnelling in urban areas is predominantly under surface structures and on tunnelling, innumerable changes in the form of distortion take place in strata surrounding the tunnel. Extent of displacement/damage to buildings or the tunnel-soil structure interaction depends on the type of building and nature of strata. Effect on displacements has been less studied in granular soils compared to other types of soils like clays. In this paper, parametric studies are conducted to find the displacements at surface, in granular soil conditions, due to varying building storeys and building eccentricities from the tunnel centre line. Effect of presence of geosynthetic layer under footings is further studied. Prior to the parametric studies, validity of the model used is checked with field data available for a stretch of tunnel in South India. Results of simulation studies reveal that inclusion of building reduces displacements at the surface in the dense strata. In very dense strata, the displacements increase as compared to the case without a building. As the centre of the building moves away from the tunnel centre line, settlement above the tunnel matches displacements in the case without building. Applicability of 3DEC software is checked with respect to the present study. PMID:27437472

  13. A numerical study of the effects of wind tunnel wall proximity on an airfoil model

    NASA Technical Reports Server (NTRS)

    Potsdam, Mark; Roberts, Leonard

    1990-01-01

    A procedure was developed for modeling wind tunnel flows using computational fluid dynamics. Using this method, a numerical study was undertaken to explore the effects of solid wind tunnel wall proximity and Reynolds number on a two-dimensional airfoil model at low speed. Wind tunnel walls are located at varying wind tunnel height to airfoil chord ratios and the results are compared with freestream flow in the absence of wind tunnel walls. Discrepancies between the constrained and unconstrained flows can be attributed to the presence of the walls. Results are for a Mach Number of 0.25 at angles of attack through stall. A typical wind tunnel Reynolds number of 1,200,000 and full-scale flight Reynolds number of 6,000,000 were investigated. At this low Mach number, wind tunnel wall corrections to Mach number and angle of attack are supported. Reynolds number effects are seen to be a consideration in wind tunnel testing and wall interference correction methods. An unstructured grid Navier-Stokes code is used with a Baldwin-Lomax turbulence model. The numerical method is described since unstructured flow solvers present several difficulties and fundamental differences from structured grid codes, especially in the area of turbulence modeling and grid generation.

  14. Carpal Tunnel Syndrome Caused by Space Occupying Lesions

    PubMed Central

    Kang, Ho Jung; Yoon, Hong Ki; Hahn, Soo Bong; Kim, Sung Jae

    2009-01-01

    Purpose To evaluate the diagnosis and treatment of the carpal tunnel syndrome (CTS) due to space occupying lesions (SOL). Materials and Methods Eleven patients and 12 cases that underwent surgery for CTS due to SOL were studied retrospectively. We excluded SOL caused by bony lesions, such as malunion of distal radius fracture, volar lunate dislocation, etc. The average age was 51 years. There were 3 men and 8 women. Follow-up period was 12 to 40 months with an average of 18 months. The diagnosis of CTS was made clinically and electrophysiologically. In patients with swelling or tenderness on the area of wrist flexion creases, magnetic resonance imaging (MRI) and/or computed tomogram (CT) were additionally taken as well as the carpal tunnel view. We performed conventional open transverse carpal ligament release and removal of SOL. Results The types of lesion confirmed by pathologic examination were; tuberculosis tenosynovitis in 3 cases, nonspecific tenosynovitis in 2 cases, and gout in one case. Other SOLs were tumorous condition in five cases, and abnormal palmaris longus hypertrophy in 1 case. Tumorous conditions were due to calcifying mass in 4 cases and ganglion in 1 case. Following surgery, all cases showed alleviation of symptom without recurrence or complications. Conclusion In cases with swelling or tenderness on the area of wrist flexion creases, it is important to obtain a carpal tunnel view, and MRI and/or CT should be supplemented in order to rule out SOLs around the carpal tunnel, if necessary. PMID:19430560

  15. Defined Syllabuses in Modern Languages

    ERIC Educational Resources Information Center

    Harding, Ann; Honnor, Sylvia

    1974-01-01

    The advantages of a defined syllabus in second language teaching, especially in relation to public examinations, are discussed. The origin and development of the York defined syllabuses are described, and extracts are given from the introductory document and the French and Russian syllabuses. (RM)

  16. Clarifying and Defining Library Services.

    ERIC Educational Resources Information Center

    Shubert, Joseph F., Ed.; Josey, E. J., Ed.

    1991-01-01

    This issue presents articles which, in some way, help to clarify and define library services. It is hoped that this clarification in library service will serve to secure the resources libraries need to serve the people of New York. The following articles are presented: (1) Introduction: "Clarifying and Defining Library Services" (Joseph F.…

  17. Radial Tunnel Syndrome, Diagnostic and Treatment Dilemma.

    PubMed

    Moradi, Ali; Ebrahimzadeh, Mohammad H; Jupiter, Jess B

    2015-07-01

    Radial tunnel syndrome is a disease which we should consider it in elbow and forearm pains. It is diagnosed with lateral elbow and dorsal forearm pain may radiate to the wrist and dorsum of the fingers. The disease is more prevalent in women with the age of 30 to 50 years old. It occurs by intermittent compression on the radial nerve from the radial head to the inferior border of the supinator muscle, without obvious extensor muscle weakness. Compression could happen in five different sites but the arcade of Frose is the most common area that radial nerve is compressed. To diagnosis radial tunnel syndrome, clinical examination is more important than paraclinic tests such as electrodiagnsic test and imaging studies. The exact site of the pain which can more specified by rule of nine test and weakness of the third finger and wrist extension are valuable physical exams to diagnosis. MRI studies my show muscle edema or atrophy along the distribution of the posterior interosseous nerve. Although non-surgical treatments such as rest, NSAIDs, injections and physiotherapy do not believe to have permanent relief, but it is justify undergoing them before surgery. Surgery could diminish pain and symptoms in 67 to 93 percents of patients completely.

  18. Radial Tunnel Syndrome, Diagnostic and Treatment Dilemma

    PubMed Central

    Moradi, Ali; Ebrahimzadeh, Mohammad H; Jupiter, Jess B

    2015-01-01

    Radial tunnel syndrome is a disease which we should consider it in elbow and forearm pains. It is diagnosed with lateral elbow and dorsal forearm pain may radiate to the wrist and dorsum of the fingers. The disease is more prevalent in women with the age of 30 to 50 years old. It occurs by intermittent compression on the radial nerve from the radial head to the inferior border of the supinator muscle, without obvious extensor muscle weakness. Compression could happen in five different sites but the arcade of Frose is the most common area that radial nerve is compressed. To diagnosis radial tunnel syndrome, clinical examination is more important than paraclinic tests such as electrodiagnsic test and imaging studies. The exact site of the pain which can more specified by rule of nine test and weakness of the third finger and wrist extension are valuable physical exams to diagnosis. MRI studies my show muscle edema or atrophy along the distribution of the posterior interosseous nerve. Although non-surgical treatments such as rest, NSAIDs, injections and physiotherapy do not believe to have permanent relief, but it is justify undergoing them before surgery. Surgery could diminish pain and symptoms in 67 to 93 percents of patients completely. PMID:26213698

  19. Tunneling at νT = 1 in a bilayer quantum Hall exciton condensate

    NASA Astrophysics Data System (ADS)

    Nandi, D.; Khaire, T.; Finck, A. D. K.; Eisenstein, J. P.; Pfeiffer, L. N.; West, K. W.

    2014-03-01

    Closely-spaced bilayer quantum Hall systems at total filling factor νT = 1 exhibit spontaneous interlayer phase coherence. This phase coherence, which is tantamount to excitonic Bose condensation, is most dramatically revealed via interlayer tunneling measurements.In the condensed phase the tunneling current-voltage (IV) characteristic of this semiconductor system strongly resembles the dc Josephson effect observed in superconducting tunnel junctions. Here we report on a detailed study of this phenomenon. We find the maximum, or critical tunneling current Ic to be a well-defined global property of the macroscopic tunnel junction, insensitive to external circuit elements and the precise contact configuration used to observe it. Interestingly, the temperature dependence of Ic displays an unexpected scaling behavior. At the lowest temperatures the slope of the ``supercurrent'' branch of the tunneling IV curve, while extremely large, remains finite. Careful measurements in this regime suggest that dissipative processes arising from in-plane exciton transport limit the maximum tunneling conductance. Finally, comparisons of the experimentally observed IV with recent theoretical predictions will be discussed.

  20. A Seamless Ubiquitous Telehealthcare Tunnel

    PubMed Central

    Cheng, Po-Hsun; Lin, Bor-Shing; Yu, Chu; Hu, Shun-Hsiang; Chen, Sao-Jie

    2013-01-01

    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. PMID:23917812

  1. Aorta-right atrial tunnel.

    PubMed

    Sai Krishna, Cheemalapati; Baruah, Dibya Kumar; Reddy, Gangireddy Venkateswara; Panigrahi, Nanda Kishore; Suman, Kalagara; Kumar, Palli Venkata Naresh

    2010-01-01

    Aorta-right atrial tunnel is a vascular channel that originates from one of the sinuses of Valsalva and terminates in either the superior vena cava or the right atrium. The tunnel is classified as anterior or posterior, depending upon its course in relation to the ascending aorta. An origin above the sinotubular ridge differentiates the tunnel from an aneurysm of the sinus of Valsalva, and the absence of myocardial branches differentiates it from a coronary-cameral fistula. Clinical presentation ranges from an asymptomatic precordial murmur to congestive heart failure. The embryologic background and pathogenesis of this lesion are attributable either to an aneurysmal dilation of the sinus nodal artery or to a congenital weakness of the aortic media. In either circumstance, progressive enlargement of the tunnel and ultimate rupture into the low-pressure right atrium could occur under the influence of the systemic pressure.The lesion is diagnosed by use of 2-dimensional echocardiography and cardiac catheterization. Computed tomographic angiography is an additional noninvasive diagnostic tool. The possibility of complications necessitates early therapy, even in asymptomatic patients or those with a hemodynamically insignificant shunt. Available treatments are catheter-based intervention, external ligation under controlled hypotension, or surgical closure with the patient under cardiopulmonary bypass.Herein, we discuss the cases of 2 patients who had this unusual anomaly. We highlight the outcome on follow-up imaging (patient 1) and the identification and safe reimplantation of the coronary artery (patient 2).

  2. A seamless ubiquitous telehealthcare tunnel.

    PubMed

    Cheng, Po-Hsun; Lin, Bor-Shing; Yu, Chu; Hu, Shun-Hsiang; Chen, Sao-Jie

    2013-08-02

    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.

  3. [Modified Class II tunnel preparation].

    PubMed

    Rimondini, L; Baroni, C

    1991-05-15

    Tunnel preparations for restoration of Class II carious lesions in primary molars preserve the marginal ridge and minimize sacrifice of healthy tooth substructure. Materials with improved bonding to tooth structure and increase potential for fluoride release allow Class II restorations without "extension for prevention". PMID:1864420

  4. SCALING: Wind Tunnel to Flight

    NASA Astrophysics Data System (ADS)

    Bushnell, Dennis M.

    2006-01-01

    Wind tunnels have wide-ranging functionality, including many applications beyond aeronautics, and historically have been the major source of information for technological aerodynamics/aeronautical applications. There are a myriad of scaling issues/differences from flight to wind tunnel, and their study and impacts are uneven and a function of the particular type of extant flow phenomena. Typically, the most serious discrepancies are associated with flow separation. The tremendous ongoing increases in numerical simulation capability are changing and in many aspects have changed the function of the wind tunnel from a (scaled) "predictor" to a source of computational calibration/validation information with the computation then utilized as the flight prediction/scaling tool. Numerical simulations can increasingly include the influences of the various scaling issues. This wind tunnel role change has been occurring for decades as computational capability improves in all aspects. Additional issues driving this trend are the increasing cost (and time) disparity between physical experiments and computations, and increasingly stringent accuracy requirements.

  5. Spinoff from Wind Tunnel Technology

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Douglas Juanarena, a former NASA Langley instrument design engineer, found a solution to the problem of long, repetitive tunnel runs needed to measure airflow pressures. Electronically scanned pressure (ESP) replaced mechanical systems with electronic sensors. Juanarena licensed the NASA-patented technology and now manufactures ESP modules for research centers, aerospace companies, etc.

  6. Tunnel Vision in Environmental Management.

    ERIC Educational Resources Information Center

    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…

  7. Mars Surface Tunnel Element Concept

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle A.; Mary, Natalie; Howe, A. Scott; Jeffries, Sharon

    2016-01-01

    How Mars surface crews get into their ascent vehicle has profound implications for Mars surface architecture. To meet planetary protection protocols, the architecture has get Intravehicular Activity (IVA)-suited crew into a Mars Ascent Vehicle (MAV) without having to step outside into the Mars environment. Pushing EVA suit don/doff and EVA operations to an element that remains on the surface also helps to minimize MAV cabin volume, which in turn can reduce MAV cabin mass. Because the MAV will require at least seven kilograms of propellant to ascend each kilogram of cabin mass, minimal MAV mass is desired. For architectures involving more than one surface element-such as an ascent vehicle and a pressurized rover or surface habitat-a retractable tunnel is an attractive solution. Beyond addressing the immediate MAV access issue, a reusable tunnel may be useful for other surface applications once its primary mission is complete. A National Aeronautics and Space Administration (NASA) team is studying the optimal balance between surface tunnel functionality, mass, and stowed volume as part of the Evolvable Mars Campaign (EMC). The "Minimum Functional Tunnel" is a conceptual design that performs a single function. Having established this baseline configuration, the next step is to trade design options, evaluate other applications, and explore alternative solutions.

  8. The recurrent carpal tunnel syndrome.

    PubMed

    Kern, B C; Brock, M; Rudolph, K H; Logemann, H

    1993-01-01

    Sixteen out of 720 patients with carpal tunnel syndrome who had undergone surgery since 1979 were reoperated for a "recurrence" (2.2%). Twelve of these patients had been originally operated on in our department. Thus, our own recurrence rate is 1.7%. Three patients deteriorated following surgery, 6 had an unsatisfactory improvement, and in 7 the symptoms recurred after initial improvement. Eight of the reoperated patients had a predisposing disease (terminal renal insufficiency, insulin-dependent diabetes mellitus, acromegaly). In 10 of the 16 cases the initial operation had been carried out by surgeons in the first three years of training. Reoperation revealed incomplete splitting of the transverse carpal ligament in 10 cases, compression of the median nerve by the scar in 4, injury of the muscular branch in 1, and an anatomical variant as cause of incomplete decompression in 1 patient. "Recurrences" after carpal tunnel surgery are predominantly due to inadequacies of the first procedure. A remarkable number of patients (50%) has predisposing diseases. Interfascicular or epineural neurolysis and complete exposure and neurolysis of the median nerve and its branches is necessary only in cases of recurrence. Their omission at the first surgery does not result in an increased recurrence rate. Our observations indicate that the number of operations for recurrent carpal tunnel syndrome can probably be reduced when the first operation is performed with care and experience. Patients with carpal tunnel syndrome secondary to a systemic disease are particularly at risk.

  9. Tunneling in the SIS Structure

    NASA Astrophysics Data System (ADS)

    Shukrinov, Yu.; Kohandel, M.

    2000-09-01

    We discuss the effects caused by the layered structure of high temperature superconductors (HTS). We use the layered S-N model to obtain the tunneling current of the SIS structure. The current-voltage characteristic is calculated in the limit cases when dI/dV is proportional to the state density of HTS.

  10. A seamless ubiquitous telehealthcare tunnel.

    PubMed

    Cheng, Po-Hsun; Lin, Bor-Shing; Yu, Chu; Hu, Shun-Hsiang; Chen, Sao-Jie

    2013-08-01

    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. PMID:23917812

  11. Test techniques: A survey paper on cryogenic tunnels, adaptive wall test sections, and magnetic suspension and balance systems

    NASA Technical Reports Server (NTRS)

    Kilgore, Robert A.; Dress, David A.; Wolf, Stephen W. D.; Britcher, Colin P.

    1989-01-01

    The ability to get good experimental data in wind tunnels is often compromised by things seemingly beyond our control. Inadequate Reynolds number, wall interference, and support interference are three of the major problems in wind tunnel testing. Techniques for solving these problems are available. Cryogenic wind tunnels solve the problem of low Reynolds number. Adaptive wall test sections can go a long way toward eliminating wall interference. A magnetic suspension and balance system (MSBS) completely eliminates support interference. Cryogenic tunnels, adaptive wall test sections, and MSBS are surveyed. A brief historical overview is given and the present state of development and application in each area is described.

  12. A water tunnel flow visualization study of the F-15

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1978-01-01

    Water tunnel studies were performed to qualitatively define the flow field of the F-15 aircraft. Two lengthened forebodies, one with a modified cross-sectional shape, were tested in addition to the basic forebody. Particular emphasis was placed on defining vortex flows generated at high angles of attack. The flow visualization tests were conducted in the Northrop diagnostic water tunnel using a 1/48-scale model of the F-15. Flow visualization pictures were obtained over an angle-of-attack range to 55 deg and sideslip angles up to 10 deg. The basic aircraft configuration was investigated in detail to determine the vortex flow field development, vortex path, and vortex breakdown characteristics as a function of angle of attack and sideslip. Additional tests showed that the wing upper surface vortex flow fields were sensitive to variations in inlet mass flow ratio and inlet cowl deflection angle. Asymmetries in the vortex systems generated by each of the three forebodies were observed in the water tunnel at zero sideslip and high angles of attack.

  13. Aeroelastic instability stoppers for wind tunnel models

    NASA Technical Reports Server (NTRS)

    Doggett, R. V., Jr.; Ricketts, R. H. (Inventor)

    1981-01-01

    A mechanism for diverting the flow in a wind tunnel from the wing of a tested model is described. The wing is mounted on the wall of a tunnel. A diverter plate is pivotally mounted on the tunnel wall ahead of the model. An actuator fixed to the tunnel is pivotably connected to the diverter plate, by plunger. When the model is about to become unstable during the test the actuator moves the diverter plate from the tunnel wall to divert maintaining stable model conditions. The diverter plate is then retracted to enable normal flow.

  14. 2. 'Tunnel No 6 West End, Front Elevation, Sectional Elevation ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. 'Tunnel No 6 West End, Front Elevation, Sectional Elevation on Centerline of Portal,' Southern Pacific Standard Single-Track Tunnel, 1910. Tunnel 6, which today would be Tunnel 20, was daylighted and no longer exists. Compare to photos in documentation sets for Tunnel 23 (HAER No. CA-198), Tunnel 24 (HAER No. CA-200), Tunnel 25 (HAER No. CA-201), Tunnel 27 (HAER No. CA-203), Tunnel 28 (HAER No. CA-204), and Tunnel 29 (HAER No. CA-205). - Central Pacific Transcontinental Railroad, Sacramento to Nevada state line, Sacramento, Sacramento County, CA

  15. Propulsion simulation for magnetically suspended wind tunnel models

    NASA Technical Reports Server (NTRS)

    Joshi, Prakash B.; Beerman, Henry P.; Chen, James; Krech, Robert H.; Lintz, Andrew L.; Rosen, David I.

    1990-01-01

    The feasibility of simulating propulsion-induced aerodynamic effects on scaled aircraft models in wind tunnels employing Magnetic Suspension and Balance Systems. The investigation concerned itself with techniques of generating exhaust jets of appropriate characteristics. The objectives were to: (1) define thrust and mass flow requirements of jets; (2) evaluate techniques for generating propulsive gas within volume limitations imposed by magnetically-suspended models; (3) conduct simple diagnostic experiments for techniques involving new concepts; and (4) recommend experiments for demonstration of propulsion simulation techniques. Various techniques of generating exhaust jets of appropriate characteristics were evaluated on scaled aircraft models in wind tunnels with MSBS. Four concepts of remotely-operated propulsion simulators were examined. Three conceptual designs involving innovative adaptation of convenient technologies (compressed gas cylinders, liquid, and solid propellants) were developed. The fourth innovative concept, namely, the laser-assisted thruster, which can potentially simulate both inlet and exhaust flows, was found to require very high power levels for small thrust levels.

  16. Torque Sensor Based on Tunnel-Diode Oscillator

    NASA Technical Reports Server (NTRS)

    Chui, Talso; Young, Joseph

    2008-01-01

    A proposed torque sensor would be capable of operating over the temperature range from 1 to 400 K, whereas a typical commercially available torque sensor is limited to the narrower temperature range of 244 to 338 K. The design of this sensor would exploit the wide temperature range and other desirable attributes of differential transducers based on tunnel-diode oscillators as described in "Multiplexing Transducers Based on Tunnel-Diode Oscillators". The proposed torque sensor would include three flexural springs that would couple torque between a hollow outer drive shaft and a solid inner drive shaft. The torque would be deduced from the torsional relative deflection of the two shafts, which would be sensed via changes in capacitances of two capacitors defined by two electrodes attached to the inner shaft and a common middle electrode attached to the outer shaft.

  17. A tunnel boring system for the Yucca Mountain Project

    SciTech Connect

    Short, S.N.

    1994-12-31

    Design of the Yucca Mountain Project (YMP) tunnel boring machine (TBM) and backup began in June of 1993, with fabrication, machining and light assembly proceeding through to the end of the year. The original specifications for the project were contained in the request for quote for the YMP TBM and in Construction & Tunneling Services proposal document. As with all complex custom assignments, much of the finer details of the definition of the final scope of delivery was concurrent with the design effort itself. The summation of this effort is described in this paper. The major technical scope of the machine delivery is defined by the parameters listed in TABLE 1. Within the confines of the installed power and design excavation rates, the final product has been tailored to suit the particular needs of the project.

  18. Description and calibration of the Langley unitary plan wind tunnel

    NASA Technical Reports Server (NTRS)

    Jackson, C. M., Jr.; Corlett, W. A.; Monta, W. J.

    1981-01-01

    The two test sections of the Langley Unitary Plan Wind Tunnel were calibrated over the operating Mach number range from 1.47 to 4.63. The results of the calibration are presented along with a a description of the facility and its operational capability. The calibrations include Mach number and flow angularity distributions in both test sections at selected Mach numbers and tunnel stagnation pressures. Calibration data are also presented on turbulence, test-section boundary layer characteristics, moisture effects, blockage, and stagnation-temperature distributions. The facility is described in detail including dimensions and capacities where appropriate, and example of special test capabilities are presented. The operating parameters are fully defined and the power consumption characteristics are discussed.

  19. Large magnetoresistance of paracyclophane-based molecular tunnel junctions: A first-principles study

    SciTech Connect

    Tao, L. L.; Liang, S. H.; Liu, D. P.; Han, X. F.

    2013-12-07

    We report a theoretical study of magnetoresistance and spin-polarized transport of a series of paracyclophane-based molecular tunnel junctions. We predict that the molecular tunnel junction using [2.2]-paracyclophane barrier has the desired low resistance area product in combination with high magnetoresistance ratio. In addition, we find the spin-polarized conductance decreases exponentially with increasing the molecular length, indicating a nonresonant tunneling mechanism. In particular, the characteristic decay constant can be theoretically evaluated from the complex band structure of periodic paracyclophane molecule. The spin-polarized transport mechanism is systematically analyzed.

  20. Resonant Tunneling of Spin-Wave Packets via Quantized States in Potential Wells

    NASA Astrophysics Data System (ADS)

    Hansen, Ulf-Hendrik; Gatzen, Marius; Demidov, Vladislav E.; Demokritov, Sergej O.

    2007-09-01

    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.

  1. The Problem of Defining Intelligence.

    ERIC Educational Resources Information Center

    Lubar, David

    1981-01-01

    The major philosophical issues surrounding the concept of intelligence are reviewed with respect to the problems surrounding the process of defining and developing artificial intelligence (AI) in computers. Various current definitions and problems with these definitions are presented. (MP)

  2. Geophysical investigations in deep horizontal holes drilled ahead of tunnelling

    USGS Publications Warehouse

    Carroll, R.D.; Cunningham, M.J.

    1980-01-01

    Deep horizontal drill holes have been used since 1967 by the Defense Nuclear Agency as a primary exploration tool for siting nuclear events in tunnels at the Nevada Test Site. The U.S. Geological Survey had developed geophysical logging techniques for obtaining resistivity and velocity in these holes, and to date 33 horizontal drill holes in excess of 300 m in depth have been successfully logged. The deepest hole was drilled to a horizontal depth of 1125 m. The purposes of the logging measurements are to define clay zones, because of the unstable ground conditions such zones can present to tunnelling, and to define zones of partially saturated rock, because of the attenuating effects such zones have on the shock wave generated by the nuclear detonation. Excessive attenuation is undesirable because the shock wave is used as a tunnel closure mechanism to contain debris and other undesirable explosion products. Measurements are made by pumping resistivity, sonic and geophone probes down the drill string and out of the bit into the open hole. Clay zones are defined by the electrical resistivity technique based on empirical data relating the magnitude of the resistivity measurement to qualitative clay content. Rock exhibiting resistivity of less than 20 ??-m is considered potentially unstable, and resistivities less than 10 ??-m indicate appreciable amounts of clay are present in the rock. Partially saturated rock zones are defined by the measurement of the rock sound speed. Zones in the rock which exhibit velocities less than 2450 m/sec are considered of potential concern. ?? 1980.

  3. A Historical Evaluation of the U16a Tunnel, Nevada National Security Site, Nye County, Nevada Volume 1

    SciTech Connect

    Jones, robert C; Drollinger, Harold; Bullard, Thomas F; Ashbaugh, Laurence J; Griffin, Wayne R

    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

  4. A Historical Evaluation of the U16a Tunnel, Nevada National Security Site, Nye County, Nevada Volume 2

    SciTech Connect

    Jones, Roberrt C; Drollinger, Harold

    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

  5. Wind tunnel studies of gas dispersion over complex terrain

    NASA Astrophysics Data System (ADS)

    Michálek, Petr; Zacho, David

    2016-03-01

    Wind tunnel studies of gas dispersion over complex terrain model were performed in VZLU Prague. The terrain model with a ground-level emission source was mounted in a boundary layer wind tunnel. Flow and concentration field behind the source was measured. The model presented an area of the Liberec city, 9.0 × 2.4 km in full scale. The emission source was mounted at the position of a heating plant in the model centre and concentration field was measured using flame ionisation detectors. The experimental results will be used for validation and verification of a new computational dispersion model intended for use in case of accidents with dangerous gas leakages in selected areas in Czech Republic.

  6. Slotted-wall research with disk and parachute models in a low-speed wind tunnel

    SciTech Connect

    Macha, J.M.; Buffington, R.J.; Henfling, J.L. ); Every, D. Van; Harris, J.L. )

    1990-01-01

    An experimental investigation of slotted-wall blockage interference has been conducted using disk and parachute models in a low speed wind tunnel. Test section open area ratio, model geometric blockage ratio, and model location along the length of the test section were systematically varied. Resulting drag coefficients were compared to each other and to interference-free measurements obtained in a much larger wind tunnel where the geometric blockage ratio was less than 0.0025. 9 refs., 10 figs.

  7. Single-contact tunneling thermometry

    DOEpatents

    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.

  8. Harmonic multiplication using resonant tunneling

    NASA Technical Reports Server (NTRS)

    Sollner, T. C. L. G.; Brown, E. R.; Goodhue, W. D.; Correa, C. A.

    1988-01-01

    This paper demonstrates the use of resonant-tunneling diodes as varistors for harmonic multiplication. It is shown that efficient odd-harmonic conversion is possible and that even harmonics do not appear because of the antisymmetry of the current-voltage (I-V) curve. It is also shown that, with the proper choice of resonant-tunneling structure and pump amplitude, most of the harmonic output power can be confined to a single odd-harmonic frequency. Fifth-harmonic multiplication was demonstrated with an output at 21.75 GHz and a power conversion efficiency of 0.5 percent, and a fifth-harmonic efficiency of 2.7 percent was achieved in a circuit simulation using an improved I-V curve.

  9. Observing remnants by fermions' tunneling

    SciTech Connect

    Chen, D.Y.; Wu, H.W.; Yang, H. E-mail: iverwu@uestc.edu.cn

    2014-03-01

    The standard Hawking formula predicts the complete evaporation of black holes. In this paper, we introduce effects of quantum gravity into fermions' tunneling from Reissner-Nordstrom and Kerr black holes. The quantum gravity effects slow down the increase of Hawking temperatures. This property naturally leads to a residue mass in black hole evaporation. The corrected temperatures are affected by the quantum numbers of emitted fermions. Meanwhile, the temperature of the Kerr black hole is a function of θ due to the rotation.

  10. Variable density turbulence tunnel facility.

    PubMed

    Bodenschatz, E; Bewley, G P; Nobach, H; Sinhuber, M; Xu, H

    2014-09-01

    The Variable Density Turbulence Tunnel at the Max Planck Institute for Dynamics and Self-Organization in Göttingen, Germany, produces very high turbulence levels at moderate flow velocities, low power consumption, and adjustable kinematic viscosity between 10(-4) m(2)/s and 10(-7) m(2)/s. The Reynolds number can be varied by changing the pressure or flow rate of the gas or by using different non-flammable gases including air. The highest kinematic viscosities, and hence lowest Reynolds numbers, are reached with air or nitrogen at 0.1 bar. To reach the highest Reynolds numbers the tunnel is pressurized to 15 bars with the dense gas sulfur hexafluoride (SF6). Turbulence is generated at the upstream ends of two measurement sections with grids, and the evolution of this turbulence is observed as it moves down the length of the sections. We describe the instrumentation presently in operation, which consists of the tunnel itself, classical grid turbulence generators, and state-of-the-art nano-fabricated hot-wire anemometers provided by Princeton University [M. Vallikivi, M. Hultmark, S. C. C. Bailey, and A. J. Smits, Exp. Fluids 51, 1521 (2011)]. We report measurements of the characteristic scales of the flow and of turbulent spectra up to Taylor Reynolds number R(λ) ≈ 1600, higher than any other grid-turbulence experiment. We also describe instrumentation under development, which includes an active grid and a Lagrangian particle tracking system that moves down the length of the tunnel with the mean flow. In this configuration, the properties of the turbulence are adjustable and its structure is resolvable up to R(λ) ≈ 8000.

  11. New treatment of quantum tunneling

    NASA Astrophysics Data System (ADS)

    Defendi, Antonio; Roncadelli, Marco

    1994-04-01

    We explore the implications of the recently proposed Langevin quantization for quantum tunneling, working within the semiclassical approximation. As far as we can see, the present treatment is simpler and more straightforward than the path integral approach. In fact, no extra trick is needed and the correct result follows at once - as a consequence of general principles - from the representation of the propagator supplied by the Langevin quantization. Further applications of the strategy discussed in this Letter are pointed out.

  12. Electrodiagnosis of carpal tunnel syndrome.

    PubMed

    Wang, Leilei

    2013-02-01

    This article discusses the historical aspects related to the understanding of carpal tunnel syndrome (CTS) and its diagnosis, highlighting observations about this disease that have yet to be challenged. This is followed by a discussion regarding the use of electrodiagnostic testing as a diagnostic tool for CTS, as well as the author's approach to making the diagnosis of CTS. Finally, conclusions about future directions in the diagnosis and treatment of this disorder are presented.

  13. Referral guidelines: carpal tunnel syndrome.

    PubMed

    Laws, E R

    1997-07-15

    The contribution on the postoperative management and rehabilitation of patients with carpal tunnel syndrome should be carefully considered by every surgeon. The operation is simply not over when the last stitch goes in; careful postoperative management is quite important if one is to obtain optimal surgical results. The principles outlined here are valuable and help to explain the occasional poor outcome. We have become convinced that the use of a dorsal splint in the 1st week to 10 days following surgery is a helpful measure. It is designed to prevent the median nerve from prolapsing forward and becoming adherent to or trapped by the edges of the severed transverse carpal ligament. With regard to surgical management of carpal tunnel syndrome. It is exceedingly important to continue producing outcome studies showing that our interventions really do eliminate the problem and allow people to return to productive work. Templates for outcome assessment are under development by the Outcomes Committee of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons and also by the American College of surgeons. Hopefully, they can be applied to the treatment of carpal tunnel syndrome. The following segment represents some suggested referral guidelines for patients with carpal tunnel syndrome. The present differential diagnosis, methods of confirming the diagnosis, and appropriate indications for considering surgery. These guidelines have been reviewed by the various authors who have contributed to this issue of Neurosurgical Focus and other colleagues in neurosurgery, orthopedics, plastic surgery, neurology, and occupational therapy. It is hoped that they will be a reasonable start in our efforts to inform referring physicians as to the nature of median thenar neuropathy and its overall management.

  14. Neurolysis for failed tarsal tunnel surgery.

    PubMed

    Yalcinkaya, Merter; Ozer, Utku Erdem; Yalcin, M Burak; Bagatur, A Erdem

    2014-01-01

    The purpose of the present study was to investigate the causes of failure after tarsal tunnel release and the operative findings in the secondary interventions and the outcomes. The data from 8 patients who had undergone revision surgery for failed tarsal tunnel release at least 12 months earlier were evaluated retrospectively. Only the patients with idiopathic tarsal tunnel syndrome were included, and all had unilateral symptoms. Neurophysiologic tests confirmed the clinical diagnosis of failed tarsal tunnel release in all patients. Magnetic resonance imaging revealed varicose veins within the tarsal tunnel in 1 patient (12.5%) and tenosynovitis in another (12.5%). Open tarsal tunnel release was performed in all patients, and the tibialis posterior nerve, medial and lateral plantar nerves (including the first branch of the lateral plantar nerve), and medial calcaneal nerve were released in their respective tunnels, and the septum between the tunnels was resected. The outcomes were assessed according to subjective patient satisfaction as excellent, good, fair, or poor. During revision surgery, insufficient release of the tarsal tunnel, especially distally, was observed in all the patients, and fibrosis of the tibialis posterior nerve was present in 1 (12.5%). The outcomes according to subjective patient satisfaction were excellent in 5 (62.5%), good in 2 (25%), and fair in 1 (12.5%). The fair outcome was obtained in the patient with fibrosis of the nerve. Insufficient release of the tarsal tunnel was the main cause of failed tarsal tunnel release. Releasing the 4 distinct tunnels and permitting immediate mobilization provided satisfactory results in patients with failed tarsal tunnel release. PMID:25128912

  15. 9. "TEST STAND; STRUCTURAL; CABLE TUNNEL, PLAN, SECTIONS, DETAILS." Specifications ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. "TEST STAND; STRUCTURAL; CABLE TUNNEL, PLAN, SECTIONS, DETAILS." Specifications No. OC1-55-72-(Rev.); Drawing No. 60-09-12; sheet 43 of 148; file no. AF 1320/94, Rev. A. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract no. 4338, no change. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A Terminal Room, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

  16. Confocal Annular Josephson Tunnel Junctions

    NASA Astrophysics Data System (ADS)

    Monaco, Roberto

    2016-09-01

    The physics of Josephson tunnel junctions drastically depends on their geometrical configurations and here we show that also tiny geometrical details play a determinant role. More specifically, we develop the theory of short and long annular Josephson tunnel junctions delimited by two confocal ellipses. The behavior of a circular annular Josephson tunnel junction is then seen to be simply a special case of the above result. For junctions having a normalized perimeter less than one, the threshold curves in the presence of an in-plane magnetic field of arbitrary orientations are derived and computed even in the case with trapped Josephson vortices. For longer junctions, a numerical analysis is carried out after the derivation of the appropriate motion equation for the Josephson phase. We found that the system is modeled by a modified and perturbed sine-Gordon equation with a space-dependent effective Josephson penetration length inversely proportional to the local junction width. Both the fluxon statics and dynamics are deeply affected by the non-uniform annulus width. Static zero-field multiple-fluxon solutions exist even in the presence of a large bias current. The tangential velocity of a traveling fluxon is not determined by the balance between the driving and drag forces due to the dissipative losses. Furthermore, the fluxon motion is characterized by a strong radial inward acceleration which causes electromagnetic radiation concentrated at the ellipse equatorial points.

  17. Water jet assisted tunnel boring

    SciTech Connect

    Ozdemir, L.

    1984-06-21

    Mechanical tunnel boring has experienced significant growth over the last two decades. Improved machine design and performance coupled with a better understanding of factors affecting boreability have contributed to a dramatic increase in the number of machine bored tunnels. Today, tunnel boring machines (TBMs) are finding widespread application in various sectors of underground construction industry, both civil and mining. Most of the hard rock formations considered unsuited to mechanical boring only a few years ago are now excavated with TBMs with favorable economics compared to conventional drill and blast methods. Despite the advancements accomplished, TBMs need further improvements in design and operation to exend their capabilities and to reduce excavation costs, particularly in hard, abrasive rocks. The design of TBMs has presently reached a state where no additional major breakthroughs are anticipated in the near future. The cutter material appears to be the major obstacle to achieving further performance improvements. The amount of load which the cutters can sustain with acceptable levels of wear is the limiting factor determining the magnitude of the power that can be placed on a TBM. In fact, most present day TBMs can generate more thrust and torque than the individual cutters are capable of supporting.

  18. Models for cryogenic wind tunnels

    NASA Technical Reports Server (NTRS)

    Lawing, Pierce L.

    1989-01-01

    Model requirements, types of model construction methods, and research in new ways to build models are discussed. The 0.3-m Transonic Cryogenic Tunnel was in operation for 16 years and many 2-D airfoil pressure models were tested. In addition there were airfoil models dedicated to transition detection techniques and other specialized research. There were also a number of small 3-D models tested. A chronological development in model building technique is described which led to the construction of many successful models. The difficulties of construction are illustrated by discussing several unsuccessful model fabrication attempts. The National Transonic Facility, a newer and much larger tunnel, was used to test a variety of models including a submarine, transport and fighter configurations, and the Shuttle Orbiter. A new method of building pressure models was developed and is described. The method is centered on the concept of bonding together plates with pressure channels etched into the bond planes, which provides high density pressure instrumentation with minimum demand on parent model material. With care in the choice of materials and technique, vacuum brazing can be used to produce strong bonds without blocking pressure channels and with no bonding voids between channels. Using multiple plates, a 5 percent wing with 96 orifices was constructed and tested in a transonic cryogenic wind tunnel. Samples of test data are presented and future applications of the technology are suggested.

  19. The optimum hypersonic wind tunnel

    NASA Technical Reports Server (NTRS)

    Trimmer, L. L.; Cary, A., Jr.; Voisinet, R. L. P.

    1986-01-01

    The capabilities of existing hypersonic wind tunnels in the U.S. are assessed to form a basis for recommendations for a new, costly facility which would provide data for modeling the hypervelocity aerodynamics envisioned for the new generation of aerospace vehicles now undergoing early studies. Attention is given to the regimes, both entry and aerodynamic, which the new vehicles will encounter, and the shortcomings of data generated for the Orbiter before flight are discussed. The features of foreign-gas, impulse, aeroballistic range, arc-heated and combustion-heated facilities are examined, noting that in any hypersonic wind tunnel the flow must be preheated to prevent liquefaction upon expansion in the test channel. The limitations of the existing facilities and the identification of the regimes which must be studied lead to a description of the characteristics of an optimum hypersonic wind tunnel, including the operations and productivity, the instrumentation, the nozzle design and the flow quality. Three different design approaches are described, each costing at least $100 million to achieve workability.

  20. Quantum Tunneling Affects Engine Performance.

    PubMed

    Som, Sibendu; Liu, Wei; Zhou, Dingyu D Y; Magnotti, Gina M; Sivaramakrishnan, Raghu; Longman, Douglas E; Skodje, Rex T; Davis, Michael J

    2013-06-20

    We study the role of individual reaction rates on engine performance, with an emphasis on the contribution of quantum tunneling. It is demonstrated that the effect of quantum tunneling corrections for the reaction HO2 + HO2 = H2O2 + O2 can have a noticeable impact on the performance of a high-fidelity model of a compression-ignition (e.g., diesel) engine, and that an accurate prediction of ignition delay time for the engine model requires an accurate estimation of the tunneling correction for this reaction. The three-dimensional model includes detailed descriptions of the chemistry of a surrogate for a biodiesel fuel, as well as all the features of the engine, such as the liquid fuel spray and turbulence. This study is part of a larger investigation of how the features of the dynamics and potential energy surfaces of key reactions, as well as their reaction rate uncertainties, affect engine performance, and results in these directions are also presented here.

  1. Defining the states of consciousness.

    PubMed

    Tassi, P; Muzet, A

    2001-03-01

    Consciousness remains an elusive concept due to the difficulty to define what has been regarded for many years as a subjective experience, therefore irrelevant for scientific study. Recent development in this field of research has allowed to provide some new insight to a possible way to define consciousness. Going through the extensive literature in this domain, several perspectives are proposed to define this concept. (1) Consciousness and Attention may not reflect the same process. (2) Consciousness during wake and sleep may not involve the same mechanisms. (3) Besides physiological states of consciousness, human beings can experience modified states of consciousness either by self-training (transcendental meditation, hypnosis, etc.) or by drug intake (hallucinogens, anaesthetics, etc.). Altogether, we address the question of a more precise terminology, given the theoretical weight words can convey. To this respect, we propose different definitions for concepts like consciousness, vigilance, arousal and alertness as candidates to separate functional entities.

  2. Development of a quiet supersonic wind tunnel with a cryogenic adaptive nozzle

    NASA Technical Reports Server (NTRS)

    Wolf, Stephen W. D.

    1993-01-01

    The main objective of this work is to develop an interim Quiet (low-disturbance) supersonic wind tunnel for the NASA-Ames Fluid Mechanics Laboratory (FML). The main emphasis is to bring on-line a full-scale Mach 1.6 tunnel as rapidly as possible to impact the NASA High Speed Research Program (HSRP). The development of a cryogenic adaptive nozzle and other sophisticated features of the tunnel will now happen later, after the full scale wind tunnel is in operation. The work under this contract for the period of this report can be summarized as follows: provide aerodynamic design requirements for the NASA-Ames Fluid Mechanics Laboratory (FML) Laminar Flow Supersonic Wind Tunnel (LFSWT); research design parameters for a unique Mach 1.6 drive system for the LFSWT using an 1/8th-scale Proof-of-Concept (PoC) supersonic wind tunnel; carry out boundary layer transition studies in PoC to aid the design of critical components of the LFSWT; appraise the State of the Art in quiet supersonic wind tunnel design; and help develop a supersonic research capability within the FML particularly in the areas of high speed transition measurements and schlieren techniques. The body of this annual report summarizes the work of the Principal Investigator.

  3. Design and evaluation of natural light guiding system in ecological illumination of traffic tunnel

    NASA Astrophysics Data System (ADS)

    Chen, Cheng-Nan; Chen, Yi-Yung; Whang, Allen Jong-Woei; Chen, Li-Hsien

    2009-08-01

    Ecological traffic tunnel means that the manner can deal with tunnel project environmental problem of surrounding area and it is most close to the green environment. In general, we always use artificial light sources, such as traditional light sources and LED, to be the light source of illumination in the traffic tunnel. However, the best light source for the health of the human body is the natural light. If we can guide the sunlight into the tunnel to be lighting source, it would have a great benefit to the health of the human body. In this paper, we use Natural Light Guiding System to provide ecological illumination in traffic tunnel. The system has collecting, transmitting, and lighting parts. In the collecting part, we utilize a static concentrator to collect sunlight which is made up of a prismatic and cascadable unit. In the transmitting part, the collected sunlight is guided by optical fiber or lightpipe efficiently. In the lighting part, we design a lighting module of road lamp for lighting the inside the tunnel. The lighting module redistributes light to conform the traffic regulation. Finally, we build a model of traffic tunnel in optical software with Natural Light Guiding System to simulate the performance.

  4. 1. West portal of Tunnel 26, contextual view to northeast ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. West portal of Tunnel 26, contextual view to northeast from atop Tunnel 25 (HAER CA-201), with Tunnel 27 (HAER CA-203) visible in distance, 210mm lens. View is along new line, with original Central Pacific Transcontinental line crossing over the top above Tunnel 26. - Central Pacific Transcontinental Railroad, Tunnel No. 26, Milepost 133.29, Applegate, Placer County, CA

  5. Inspection and rehabilitation of tunnels across faults

    SciTech Connect

    Abramson, L.W.; Schmidt, B.

    1995-12-31

    The inspection and rehabilitation of tunnels that cross faults is unique because they usually are in use and have a large variety of alternative lining types including bare rock, concrete, or steel often coated with accumulations of dirt, grime, algae and other minerals. Inspection methods are important including what to look for, how to clean the inner tunnel lining surfaces, non-destructive testing, coring, soundings, air quality detection and protection, ventilation, lightning, etc. Rehabilitation of tunnels crossing faults requires a practiced knowledge of underground design and construction practices. The most common methods of rehabilitation include grouting and concreting. The Variety of water, wastewater, transit, and highway tunnels in California provide ample examples of tunnels, new and old, that cross active faults. This paper will address specific methods of tunnel inspection and maintenance at fault crossings and give examples of relevant highway, transit, water, and wastewater projects and studies in California to demonstrate the discussions presented.

  6. Wind-tunnel procedure for determination of critical stability and control characteristics of airplanes

    NASA Technical Reports Server (NTRS)

    Goett, Harry J; Jackson, Roy P; Belsley, Steven E

    1944-01-01

    This report outlines the flight conditions that are usually critical in determining the design of components of an airplane which affect its stability and control characteristics. The wind-tunnel tests necessary to determine the pertinent data for these conditions are indicated, and the methods of computation used to translate these data into characteristics which define the flying qualities of the airplane are illustrated.

  7. Wind-Tunnel Procedure for Determination of Critical Stability and Control Characteristics of Airplanes

    NASA Technical Reports Server (NTRS)

    Goett, Harry J.; Jackson, Roy P.; Belsley, Steven E.

    1944-01-01

    This report outlines the flight conditions that are usually critical in determining the design of components of an airplane which affect its stability and control characteristics. The wind-tunnel tests necessary to determine the pertinent data for these conditions are indicated, and the methods of computation used to translate these data into characteristics which define the flying qualities of the airplane are illustrated.

  8. User's guide to STIPPAN: A panel method program for slotted tunnel interference prediction

    NASA Technical Reports Server (NTRS)

    Kemp, W. B., Jr.

    1985-01-01

    Guidelines are presented for use of the computer program STIPPAN to simulate the subsonic flow in a slotted wind tunnel test section with a known model disturbance. Input data requirements are defined in detail and other aspects of the program usage are discussed in more general terms. The program is written for use in a CDC CYBER 200 class vector processing system.

  9. Defining "Folklore" in the Classroom.

    ERIC Educational Resources Information Center

    Falke, Anne

    Folklore, a body of traditional beliefs of a people conveyed orally or by means of custom, is very much alive, involves all people, and is not the study of popular culture. In studying folklore, the principal tasks of the folklorist have been defined as determining definition, classification, source (the folk), origin (who composed folklore),…

  10. Defining and Measuring Psychomotor Performance

    ERIC Educational Resources Information Center

    Autio, Ossi

    2007-01-01

    Psychomotor performance is fundamental to human existence. It is important in many real world activities and nowadays psychomotor tests are used in several fields of industry, army, and medical sciences in employee selection. This article tries to define psychomotor activity by introducing some psychomotor theories. Furthermore the…

  11. SOFIA 2 model telescope wind tunnel test report

    NASA Technical Reports Server (NTRS)

    Keas, Paul

    1995-01-01

    This document outlines the tests performed to make aerodynamic force and torque measurements on the SOFIA wind tunnel model telescope. These tests were performed during the SOFIA 2 wind tunnel test in the 14 ft wind tunnel during the months of June through August 1994. The test was designed to measure the dynamic cross elevation moment acting on the SOFIA model telescope due to aerodynamic loading. The measurements were taken with the telescope mounted in an open cavity in the tail section of the SOFIA model 747. The purpose of the test was to obtain an estimate of the full scale aerodynamic disturbance spectrum, by scaling up the wind tunnel results (taking into account differences in sail area, air density, cavity dimension, etc.). An estimate of the full scale cross elevation moment spectrum was needed to help determine the impact this disturbance would have on the telescope positioning system requirements. A model of the telescope structure, made of a light weight composite material, was mounted in the open cavity of the SOFIA wind tunnel model. This model was mounted via a force balance to the cavity bulkhead. Despite efforts to use a 'stiff' balance, and a lightweight model, the balance/telescope system had a very low resonant frequency (37 Hz) compared to the desired measurement bandwidth (1000 Hz). Due to this mechanical resonance of the balance/telescope system, the balance alone could not provide an accurate measure of applied aerodynamic force at the high frequencies desired. A method of measurement was developed that incorporated accelerometers in addition to the balance signal, to calculate the aerodynamic force.

  12. Wind-Tunnel/Flight Correlation, 1981

    NASA Technical Reports Server (NTRS)

    Mckinney, L. W. (Editor); Baals, D. D. (Editor)

    1982-01-01

    Wind-tunnel/flight correlation activities are reviewed to assure maximum effectiveness of the early experimental programs of the National Transonic Facility (NTF). Topics included a status report of the NTF, the role of tunnel-to-tunnel correlation, a review of past flight correlation research and the resulting data base, the correlation potential of future flight vehicles, and an assessment of the role of computational fluid dynamics.

  13. Homoepitaxial graphene tunnel barriers for spin transport

    NASA Astrophysics Data System (ADS)

    Friedman, Adam

    Tunnel barriers are key elements for both charge-and spin-based electronics, offering devices with reduced power consumption and new paradigms for information processing. Such devices require mating dissimilar materials, raising issues of heteroepitaxy, interface stability, and electronic states that severely complicate fabrication and compromise performance. Graphene is the perfect tunnel barrier. It is an insulator out-of-plane, possesses a defect-free, linear habit, and is impervious to interdiffusion. Nonetheless, true tunneling between two stacked graphene layers is not possible in environmental conditions (magnetic field, temperature, etc.) usable for electronics applications. However, two stacked graphene layers can be decoupled using chemical functionalization. We demonstrate successful tunneling, charge, and spin transport with a fluorinated graphene tunnel barrier on a graphene channel. We show that while spin transport stops short of room temperature, spin polarization efficiency values are the highest of any graphene spin devices. We also demonstrate that hydrogenation of graphene can also be used to create a tunnel barrier. We begin with a four-layer stack of graphene and hydrogenate the top few layers to decouple them from the graphene transport channel beneath. We demonstrate successful tunneling by measuring non-linear IV curves and a weakly temperature dependent zero-bias resistance. We demonstrate lateral transport of spin currents in non-local spin-valve structures and determine spin lifetimes with the non-local Hanle effect to be commensurate with previous studies. The measured spin polarization efficiencies for hydrogenated graphene are higher than most oxide tunnel barriers on graphene, but not as high as with fluorinated graphene tunnel barriers. However, here we show that spin transport persists up to room temperature. Our results for the hydrogenated graphene tunnel barriers are compared with fluorinated tunnel barriers and we discuss the

  14. Method of fabrication of Josephson tunnel junction

    SciTech Connect

    Michikami, O.; Katoh, Y.; Takenaka, H.; Tanabe, K.; Yoshii, S.

    1983-11-01

    There is disclosed a method of fabrication of a Josephson tunnel junction device. A surface of a base electrode of Nb or Nb compound is subjected to sputter cleaning and then to plasma oxidation in an atmosphere of a diluent gas and oxygen to form thereon an oxide layer serving as a tunnel barrier. A counter electrode is then formed on the oxide layer to provide the Josephson tunnel junction.

  15. Modernization and Activation of the NASA Ames 11- by 11-Foot Transonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Kmak, Frank J.

    2000-01-01

    The Unitary Plan Wind Tunnel (UPWT) was modernized to improve performance, capability, productivity, and reliability. Automation systems were installed in all three UPWT tunnel legs and the Auxiliaries facility. Major improvements were made to the four control rooms, model support systems, main drive motors, and main drive speed control. Pressure vessel repairs and refurbishment to the electrical distribution system were also completed. Significant changes were made to improve test section flow quality in the 11-by 11-Foot Transonic leg. After the completion of the construction phase of the project, acceptance and checkout testing was performed to demonstrate the capabilities of the modernized facility. A pneumatic test of the tunnel circuit was performed to verify the structural integrity of the pressure vessel before wind-on operations. Test section turbulence, flow angularity, and acoustic parameters were measured throughout the tunnel envelope to determine the effects of the tunnel flow quality improvements. The new control system processes were thoroughly checked during wind-off and wind-on operations. Manual subsystem modes and automated supervisory modes of tunnel operation were validated. The aerodynamic and structural performance of both the new composite compressor rotor blades and the old aluminum rotor blades was measured. The entire subsonic and supersonic envelope of the 11-by 11-Foot Transonic leg was defined up to the maximum total pressure.

  16. 13. Groundwater in urban seashore sediments affected by tunnel constructions

    NASA Astrophysics Data System (ADS)

    Kitterød, Nils-Otto

    2014-05-01

    The purpose of this study was to examine the impact of a planned tunnel construction on the local groundwater level in the archeological deposits at the Old Wharf (Bryggen) of Bergen. The groundwater level is a function of infiltration rates, transmissivity, and boundary conditions. These variables were deduced from available data and supplemented by leakage measurements into the existing Railway tunnel located upstream of the Bryggen area. Previous studies have documented that the pore water in the deposits at Bryggen has different origin (viz fresh precipitation; leakage from drainage systems; infiltration of seawater; infiltration via the bedrock). The catchment of Bryggen is characterized by variable topography (from sea level to about 500 m a.m.s.l.) and steep gradients. Major parts of the catchment have very sparse sediment cover and can be considered as exposed bedrock. The major sediment volumes are deposited close to the sea front. In the upper part of the catchment, the groundwater level in the bedrock is close to the surface. Some observations indicate that boreholes located in lower part of the catchment have artesian pressure, which implies that there is a groundwater flux from the bedrock and into the sediments. Based on this conceptual model, a numerical model was constructed where the seawater was the boundary condition at one side and the groundwater divide on the other side. Transmissivities in the bedrock were deduced from pumping analysis, and steady state infiltration rates was calibrated to give simulated groundwater levels that were consistent to observations. Given these model simplifications, it was possible to calculate a groundwater level in the sediments at Bryggen were all water into the sediments came from the bedrock only. The simulated groundwater level captured roughly the observed groundwater levels. After simulation of the natural groundwater level (i.e. without any artificial extraction of water in the catchment), the impact of

  17. Flow Quality Studies of the NASA Glenn Research Center Icing Research Tunnel Circuit (1995 Tests)

    NASA Technical Reports Server (NTRS)

    Arrington, E. Allen; Kee-Bowling, Bonnie A.; Gonsalez, Jose C.

    2000-01-01

    The purpose of conducting the flow-field surveys described in this report was to more fully document the flow quality in several areas of the tunnel circuit in the NASA Glenn Research Center Icing Research Tunnel. The results from these surveys provide insight into areas of the tunnel that were known to exhibit poor flow quality characteristics and provide data that will be useful to the design of flow quality improvements and a new heat exchanger for the facility. An instrumented traversing mechanism was used to survey the flow field at several large cross sections of the tunnel loop over the entire speed range of the facility. Flow-field data were collected at five stations in the tunnel loop, including downstream of the fan drive motor housing, upstream and downstream of the heat exchanger, and upstream and downstream of the spraybars located in the settling chamber upstream of the test section. The data collected during these surveys greatly expanded the data base describing the flow quality in each of these areas. The new data matched closely the flow quality trends recorded from earlier tests. Data collected downstream of the heat exchanger and in the settling chamber showed how the configuration of the folded heat exchanger affected the pressure, velocity, and flow angle distributions in these areas. Smoke flow visualization was also used to qualitatively study the flow field in an area downstream of the drive fan and in the settling chamber/contraction section.

  18. Reliability Assessment of Various Sonographic Techniques for Evaluating Carpal Tunnel Syndrome.

    PubMed

    Junck, Anthony D; Escobedo, Eva M; Lipa, Bethany M; Cronan, Michael; Anthonisen, Colleen; Poltavskiy, Eduard; Bang, Heejung; Han, Jay J

    2015-11-01

    Objectives-The aim of this study was to determine the intra- and inter-rater reliability of sonographic measurements of the median nerve cross-sectional area in individuals with carpal tunnel syndrome and healthy control participants.Methods-The median nerve cross-sectional area was evaluated by sonography in 18 participants with carpal tunnel syndrome (18 upper extremities) and 9 control participants (18 upper extremities) at 2 visits 1 week apart. Two examiners, both blinded to the presence or absence of carpal tunnel syndrome, captured independent sonograms of the median nerve at the levels of the carpal tunnel inlet, pronator quadratus, and mid-forearm. The cross-sectional area was later measured by each examiner independently. Each also traced images that were captured by the other examiner.Results-Both the intra- and inter-rater reliability rates were highest for images taken at the carpal tunnel inlet (radiologist, r = 0.86; sonographer, r = 0.87; inter-rater, r = 0.95; all P < .0001), whereas they was lowest for the pronator quadratus (r = 0.49, 0.29, and 0.72, respectively; all P < .0001). At the mid-forearm, the intra-rater reliability was lower for both the radiologist and sonographer, whereas the inter-rater reliability was relatively high (r = 0.54, 0.55, and 0.81; all P < .0001). Tracing of captured images by different examiners showed high concordance for the median cross-sectional area at the carpal tunnel inlet (r = 0.96-0.98; P < .0001).Conclusions-The highest intra- and inter-rater reliability was found at the carpal tunnel inlet. The results also demonstrate that tracing of the median nerve cross-sectional area from captured images by different examiners does not contribute significantly to measurement variability.

  19. Reliability Assessment of Various Sonographic Techniques for Evaluating Carpal Tunnel Syndrome.

    PubMed

    Junck, Anthony D; Escobedo, Eva M; Lipa, Bethany M; Cronan, Michael; Anthonisen, Colleen; Poltavskiy, Eduard; Bang, Heejung; Han, Jay J

    2015-11-01

    Objectives-The aim of this study was to determine the intra- and inter-rater reliability of sonographic measurements of the median nerve cross-sectional area in individuals with carpal tunnel syndrome and healthy control participants.Methods-The median nerve cross-sectional area was evaluated by sonography in 18 participants with carpal tunnel syndrome (18 upper extremities) and 9 control participants (18 upper extremities) at 2 visits 1 week apart. Two examiners, both blinded to the presence or absence of carpal tunnel syndrome, captured independent sonograms of the median nerve at the levels of the carpal tunnel inlet, pronator quadratus, and mid-forearm. The cross-sectional area was later measured by each examiner independently. Each also traced images that were captured by the other examiner.Results-Both the intra- and inter-rater reliability rates were highest for images taken at the carpal tunnel inlet (radiologist, r = 0.86; sonographer, r = 0.87; inter-rater, r = 0.95; all P < .0001), whereas they was lowest for the pronator quadratus (r = 0.49, 0.29, and 0.72, respectively; all P < .0001). At the mid-forearm, the intra-rater reliability was lower for both the radiologist and sonographer, whereas the inter-rater reliability was relatively high (r = 0.54, 0.55, and 0.81; all P < .0001). Tracing of captured images by different examiners showed high concordance for the median cross-sectional area at the carpal tunnel inlet (r = 0.96-0.98; P < .0001).Conclusions-The highest intra- and inter-rater reliability was found at the carpal tunnel inlet. The results also demonstrate that tracing of the median nerve cross-sectional area from captured images by different examiners does not contribute significantly to measurement variability. PMID:26453123

  20. Observation of density-induced tunneling.

    PubMed

    Jürgensen, Ole; Meinert, Florian; Mark, Manfred J; Nägerl, Hanns-Christoph; Lühmann, Dirk-Sören

    2014-11-01

    We study the dynamics of bosonic atoms in a tilted one-dimensional optical lattice and report on the first direct observation of density-induced tunneling. We show that the interaction affects the time evolution of the doublon oscillation via density-induced tunneling and pinpoint its density and interaction dependence. The experimental data for different lattice depths are in good agreement with our theoretical model. Furthermore, resonances caused by second-order tunneling processes are studied, where the density-induced tunneling breaks the symmetric behavior for attractive and repulsive interactions predicted by the Hubbard model.

  1. PUREX Storage Tunnels dangerous waste permit application

    SciTech Connect

    Not Available

    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.

  2. Observation of density-induced tunneling.

    PubMed

    Jürgensen, Ole; Meinert, Florian; Mark, Manfred J; Nägerl, Hanns-Christoph; Lühmann, Dirk-Sören

    2014-11-01

    We study the dynamics of bosonic atoms in a tilted one-dimensional optical lattice and report on the first direct observation of density-induced tunneling. We show that the interaction affects the time evolution of the doublon oscillation via density-induced tunneling and pinpoint its density and interaction dependence. The experimental data for different lattice depths are in good agreement with our theoretical model. Furthermore, resonances caused by second-order tunneling processes are studied, where the density-induced tunneling breaks the symmetric behavior for attractive and repulsive interactions predicted by the Hubbard model. PMID:25415904

  3. Tunneling Ionization Time Resolved by Backpropagation.

    PubMed

    Ni, Hongcheng; Saalmann, Ulf; Rost, Jan-Michael

    2016-07-01

    We determine the ionization time in tunneling ionization by an elliptically polarized light pulse relative to its maximum. This is achieved by a full quantum propagation of the electron wave function forward in time, followed by a classical backpropagation to identify tunneling parameters, in particular, the fraction of electrons that has tunneled out. We find that the ionization time is close to zero for single active electrons in helium and in hydrogen if the fraction of tunneled electrons is large. We expect our analysis to be essential to quantify ionization times for correlated electron motion. PMID:27447504

  4. [Morbidity with temporary disability in railway tunnel workers].

    PubMed

    Kudrin, V A; Prokhorov, A A

    2003-01-01

    The paper presents data on the health status of a large professional group of transport building workers--those who build BAM railway tunnels and those who build Moscow and Saint Petersburg underground stations. Major factors that are associated with underground work and that form the level of morbidity with temporary disability are identified. Respiratory, osteomuscular, digestive diseases, accidents, intoxications, and injuries are predominant in the structure of temporary disability. Lines of better organization of therapeutical-and-prophylactic aid to this contingent are defined. PMID:12861685

  5. Surgical efficacy of carpal tunnel release for carpal tunnel syndrome in acromegaly: report of four patients.

    PubMed

    Iwasaki, N; Masuko, T; Ishikawa, J; Minami, A

    2005-12-01

    Although carpal tunnel syndrome is frequent in acromegaly, few acromegalics will be encountered by most hand surgeons. This paper considers the treatment of four cases of acromegaly in whom carpal tunnel syndrome arose, to discuss aspects of management of carpal tunnel syndrome in this patient group.

  6. The role of sediment supply in esker formation and ice tunnel evolution

    NASA Astrophysics Data System (ADS)

    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

  7. No correlation between sonographic and electrophysiological parameters in carpal tunnel syndrome.

    PubMed

    Żyluk, A; Walaszek, I; Szlosser, Z

    2014-02-01

    A prospective study was carried out to investigate any correlation between electrophysiological and sonographic findings in patients with a clinical diagnosis of carpal tunnel syndrome. A total of 113 patients (113 wrists) in 90 women and 23 men, with a mean age of 60 years, underwent sonographic and electrophysiological examination. Fifty-five patients (48%) had mild, 43 (38%) moderate and 12 (11%) had severe conduction disturbances and three patients had normal conduction. Sonographic measurements showed a cross-sectional area of the median nerve of 9.9 mm(2) at the forearm and 17.8 mm(2) at the tunnel inlet. The mean anteroposterior diameter (height) of the nerve at the tunnel inlet was 2.7 mm, and the lowest height inside the tunnel was 1.8 mm. No correlation was found between sonographic and electrophysiological parameters.

  8. Defining the Polar Field Reversal

    NASA Technical Reports Server (NTRS)

    Upton, Lisa; Hathaway, David H.

    2013-01-01

    The polar fields on the Sun are directly related to solar cycle variability. Recently there has been interest in studying an important characteristic of the polar fields: the timing of the polar field reversals. However this characteristic has been poorly defined, mostly due to the limitations of early observations. In the past, the reversals have been calculated by averaging the flux above some latitude (i.e. 55deg or 75deg). Alternatively, the reversal could be defined by the time in which the previous polarity is completely canceled and replaced by the new polarity at 90de, precisely at the pole. We will use a surface flux transport model to illustrate the differences in the timing of the polar field reversal based on each of these definitions and propose standardization in the definition of the polar field reversal. The ability to predict the timing of the polar field reversal using a surface flux transport model will also be discussed.

  9. Tunneling splittings in vibrational spectra of non-rigid molecules. IX. Malonaldehyde and its isotopomers as a test case for fully coupled multidimensional tunneling dynamics

    NASA Astrophysics Data System (ADS)

    Benderskii, V. A.; Vetoshkin, E. V.; Irgibaeva, I. S.; Trommsdorff, H. P.

    2000-12-01

    Twenty one dimensional potential energy surfaces (PES) and the tunneling coordinate dependent kinematic matrices of malonaldehyde and of several of its isotopomers (D, 13C) are constructed in the low-energy region (<3000 cm -1) using quantum-chemical data. Even though the barrier heights calculated with different methods differ strongly (from 2.8 to 10.3 kcal mol -1), all PES become near identical after scaling, fitting only one semiclassical parameter γ, which defines the scales of potential, energy and action. The results of dynamical calculations carried out in dimensionless variables are therefore quite insensitive to the choice of the quantum-chemical method used for the construction of the Hamiltonian. Choosing the value of γ such that the calculated tunneling splitting in the ground state coincides with the experimental value, the corresponding barrier height is determined as 4.30 kcal mol -1 and the vibrational spectrum of the transition state is obtained. The perturbative instanton approach developed in the previous papers of this series is used to solve the dynamical problem without reducing the number of degrees of freedom. The role of all 20 transverse vibrations in proton tunneling is characterized. The tunneling path and globally uniform semiclassical wave functions are evaluated from the fourth-order Hamilton-Jacobi equation and the second-order transport equation. Tunneling splittings in the ground and low-lying excited states are calculated and isotope effects of H/D and 13C/12C substitutions are predicted.

  10. Help Students Tunnel Their Way to Math and Writing Skills.

    ERIC Educational Resources Information Center

    MacMath, Russ

    1987-01-01

    A teacher describes how a cardboard box tunnel was used to capitalize on children's fascination with boxes. The finished tunnel offers opportunities for honing math and writing skills. Layouts for tunnels and related activities are suggested. (MT)

  11. 4. East portal of Tunnel 25, view to southwest from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. East portal of Tunnel 25, view to southwest from west end of Tunnel 26 (HAER CA-202), 135mm lens. - Central Pacific Transcontinental Railroad, Tunnel No. 25, Milepost 133.09, Applegate, Placer County, CA

  12. View of Irving Flume Tunnel #1 showing the steel flume ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Irving Flume Tunnel #1 showing the steel flume with trestles leading into concrete tunnel. Looking south - Childs-Irving Hydroelectric Project, Irving System, Flume Tunnel No. 1, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  13. 1. West portal of Tunnel 17, contextual view to northeast, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. West portal of Tunnel 17, contextual view to northeast, 135mm lens. The tunnel penetrates the toe of Dorris Hill, which rises to the left. - Southern Pacific Railroad Natron Cutoff, Tunnel No. 17, Milepost 408, Dorris, Siskiyou County, CA

  14. 1. West portal of Tunnel 22, contextual view to the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. West portal of Tunnel 22, contextual view to the northwest, 135mm lens. Tunnel 22 pierces a ridge separating Oakridge from Westfir. - Southern Pacific Railroad Natron Cutoff, Tunnel 22, Milepost 581.85, Oakridge, Lane County, OR

  15. 4. VIEW FROM MIDDLE ADIT OF WAWONA TUNNEL AT HWY. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW FROM MIDDLE ADIT OF WAWONA TUNNEL AT HWY. 120. TUNNEL #1 IS IN LOWER CENTER OF IMAGE. - Big Oak Flat Road Tunnel No. 1, Through mountain spur on New Big Oak Flat Road, Yosemite Village, Mariposa County, CA

  16. 1. West portal of Tunnel 25, contextual view to northeast ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. West portal of Tunnel 25, contextual view to northeast from Tunnel 24 (HAER CA-200), 135mm lens. - Central Pacific Transcontinental Railroad, Tunnel No. 25, Milepost 133.09, Applegate, Placer County, CA

  17. 340. Caltrans, Photographer October 14, 1935 "TUNNEL WEST PORTAL"; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    340. Caltrans, Photographer October 14, 1935 "TUNNEL - WEST PORTAL"; VIEW OF TUNNEL - WEST PORTAL' UNDER CONSTRUCTION SHOWING EXCAVATION OF TUNNEL AFTER POUR. 5-1669 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  18. Acute carpal tunnel syndrome as a result of spontaneous bleeding

    PubMed Central

    Balakrishnan, Chenicheri; Jarrahnejad, Payam; Balakrishnan, Anila; Huettner, William C

    2008-01-01

    Acute carpal tunnel syndrome is the most common compression neuropathy of the upper extremity following trauma. A rare occurence of spontaneous bleeding into the carpal tunnel, presenting as acute carpal tunnel syndrome, is presented. PMID:19721797

  19. NORTHERN END OF VIADUCT WHERE IT ENTERS BATTERY STREET TUNNEL. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTHERN END OF VIADUCT WHERE IT ENTERS BATTERY STREET TUNNEL. LAKE UNION VISIBLE IN BACKGROUND. TUNNEL PROCEEDS IN CUT AND COVER FASHION DIRECTLY BENEATH BATTERY STREET. - Alaskan Way Viaduct and Battery Street Tunnel, Seattle, King County, WA

  20. View of Flume Tunnel #3 through Purple Mountain, showing flume ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Flume Tunnel #3 through Purple Mountain, showing flume entering into the tunnel. Looking south - Childs-Irving Hydroelectric Project, Childs System, Flume Tunnel No. 3, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  1. How do people define moderation?

    PubMed

    vanDellen, Michelle R; Isherwood, Jennifer C; Delose, Julie E

    2016-06-01

    Eating in moderation is considered to be sound and practical advice for weight maintenance or prevention of weight gain. However, the concept of moderation is ambiguous, and the effect of moderation messages on consumption has yet to be empirically examined. The present manuscript examines how people define moderate consumption. We expected that people would define moderate consumption in ways that justified their current or desired consumption rather than view moderation as an objective standard. In Studies 1 and 2, moderate consumption was perceived to involve greater quantities of an unhealthy food (chocolate chip cookies, gummy candies) than perceptions of how much one should consume. In Study 3, participants generally perceived themselves to eat in moderation and defined moderate consumption as greater than their personal consumption. Furthermore, definitions of moderate consumption were related to personal consumption behaviors. Results suggest that the endorsement of moderation messages allows for a wide range of interpretations of moderate consumption. Thus, we conclude that moderation messages are unlikely to be effective messages for helping people maintain or lose weight. PMID:26964691

  2. How do people define moderation?

    PubMed

    vanDellen, Michelle R; Isherwood, Jennifer C; Delose, Julie E

    2016-06-01

    Eating in moderation is considered to be sound and practical advice for weight maintenance or prevention of weight gain. However, the concept of moderation is ambiguous, and the effect of moderation messages on consumption has yet to be empirically examined. The present manuscript examines how people define moderate consumption. We expected that people would define moderate consumption in ways that justified their current or desired consumption rather than view moderation as an objective standard. In Studies 1 and 2, moderate consumption was perceived to involve greater quantities of an unhealthy food (chocolate chip cookies, gummy candies) than perceptions of how much one should consume. In Study 3, participants generally perceived themselves to eat in moderation and defined moderate consumption as greater than their personal consumption. Furthermore, definitions of moderate consumption were related to personal consumption behaviors. Results suggest that the endorsement of moderation messages allows for a wide range of interpretations of moderate consumption. Thus, we conclude that moderation messages are unlikely to be effective messages for helping people maintain or lose weight.

  3. Full-Scale Tunnel (FST)

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Construction of Full-Scale Tunnel (FST). In November 1929, Smith DeFrance submitted his recommendations for the general design of the Full Scale Wind Tunnel. The last on his list concerned the division of labor required to build this unusual facility. He believed the job had five parts and described them as follows: 'It is proposed that invitations be sent out for bids on five groups of items. The first would be for one contract on the complete structure; second the same as first, including the erection of the cones but not the fabrication, since this would be more of a shipyard job; third would cover structural steel, cover, sash and doors, but not cones or foundation; fourth, foundations; an fifth, fabrication of cones.' DeFrance's memorandum prompted the NACA to solicit estimates from a large number of companies. Preliminary designs and estimates were prepared and submitted to the Bureau of the Budget and Congress appropriated funds on February 20, 1929. The main construction contract with the J.A. Jones Company of Charlotte, North Carolina was signed one year later on February 12, 1930. It was a peculiar structure as the building's steel framework is visible on the outside of the building. DeFrance described this in NACA TR No. 459: 'The entire equipment is housed in a structure, the outside walls of which serve as the outer walls of the return passages. The over-all length of the tunnel is 434 feet 6 inches, the width 222 feet, and the maximum height 97 feet. The framework is of structural steel....' (pp. 292-293).

  4. Full-Scale Tunnel (FST)

    NASA Technical Reports Server (NTRS)

    1930-01-01

    Construction of Full-Scale Tunnel (FST): 120-Foot Truss hoisting, one and two point suspension. In November 1929, Smith DeFrance submitted his recommendations for the general design of the Full Scale Wind Tunnel. The last on his list concerned the division of labor required to build this unusual facility. He believed the job had five parts and described them as follows: 'It is proposed that invitations be sent out for bids on five groups of items. The first would be for one contract on the complete structure; second the same as first, including the erection of the cones but not the fabrication, since this would be more of a shipyard job; third would cover structural steel, cover, sash and doors, but not cones or foundation; fourth, foundations; and fifth, fabrication of cones.' DeFrance's memorandum prompted the NACA to solicit estimates from a large number of companies. Preliminary designs and estimates were prepared and submitted to the Bureau of the Budget and Congress appropriated funds on February 20, 1929. The main construction contract with the J.A. Jones Company of Charlotte, North Carolina was signed one year later on February 12, 1930. It was a peculiar structure as the building's steel framework is visible on the outside of the building. DeFrance described this in NACA TR No. 459: 'The entire equipment is housed in a structure, the outside walls of which serve as the outer walls of the return passages. The over-all length of the tunnel is 434 feet 6 inches, the width 222 feet, and the maximum height 97 feet. The framework is of structural steel....' (pp. 292-293)

  5. Mars Surface Tunnel Element Concept

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle A.

    2016-01-01

    How crews get into or out of their ascent vehicle has profound implications for Mars surface architecture. Extravehicular Activity (EVA) hatches and Airlocks have the benefit of relatively low mass and high Technology Readiness Level (TRL), but waste consumables with a volume depressurization for every ingress/egress. Perhaps the biggest drawback to EVA hatches or Airlocks is that they make it difficult to keep Martian dust from being tracked back into the ascent vehicle, in violation of planetary protection protocols. Suit ports offer the promise of dust mitigation by keeping dusty suits outside the cabin, but require significant cabin real estate, are relatively high mass, and current operational concepts still require an EVA hatch to get the suits outside for the first EVA, and back inside after the final EVA. This is primarily because current designs don't provide enough structural support to protect the suits from ascent/descent loads or potential thruster plume impingement. For architectures involving more than one surface element-such as an ascent vehicle and a rover or surface habitat-a retractable tunnel is an attractive option. By pushing spacesuit don/doff and EVA operations to an element that remains on the surface, ascended vehicle mass and dust can be minimized. What's more, retractable tunnels provide operational flexibility by allowing surface assets to be re-configured or built up over time. Retractable tunnel functional requirements and design concepts being developed as part of the National Aeronautics and Space Administration's (NASA) Evolvable Mars Campaign (EMC) work will add a new ingress/egress option to the surface architecture trade space.

  6. Healthcare Engineering Defined: A White Paper.

    PubMed

    Chyu, Ming-Chien; Austin, Tony; Calisir, Fethi; Chanjaplammootil, Samuel; Davis, Mark J; Favela, Jesus; Gan, Heng; Gefen, Amit; Haddas, Ram; Hahn-Goldberg, Shoshana; Hornero, Roberto; Huang, Yu-Li; Jensen, Øystein; Jiang, Zhongwei; Katsanis, J S; Lee, Jeong-A; Lewis, Gladius; Lovell, Nigel H; Luebbers, Heinz-Theo; Morales, George G; Matis, Timothy; Matthews, Judith T; Mazur, Lukasz; Ng, Eddie Yin-Kwee; Oommen, K J; Ormand, Kevin; Rohde, Tarald; Sánchez-Morillo, Daniel; Sanz-Calcedo, Justo García; Sawan, Mohamad; Shen, Chwan-Li; Shieh, Jiann-Shing; Su, Chao-Ton; Sun, Lilly; Sun, Mingui; Sun, Yi; Tewolde, Senay N; Williams, Eric A; Yan, Chongjun; Zhang, Jiajie; Zhang, Yuan-Ting

    2015-01-01

    Engineering has been playing an important role in serving and advancing healthcare. The term "Healthcare Engineering" has been used by professional societies, universities, scientific authors, and the healthcare industry for decades. However, the definition of "Healthcare Engineering" remains ambiguous. The purpose of this position paper is to present a definition of Healthcare Engineering as an academic discipline, an area of research, a field of specialty, and a profession. Healthcare Engineering is defined in terms of what it is, who performs it, where it is performed, and how it is performed, including its purpose, scope, topics, synergy, education/training, contributions, and prospects.

  7. Application of Recognition Tunneling in Single Molecule Identification

    NASA Astrophysics Data System (ADS)

    Zhao, Yanan

    Single molecule identification is one essential application area of nanotechnology. The application areas including DNA sequencing, peptide sequencing, early disease detection and other industrial applications such as quantitative and quantitative analysis of impurities, etc. The recognition tunneling technique we have developed shows that after functionalization of the probe and substrate of a conventional Scanning Tunneling Microscope with recognition molecules ("tethered molecule-pair" configuration), analyte molecules trapped in the gap that is formed by probe and substrate will bond with the reagent molecules. The stochastic bond formation/breakage fluctuations give insight into the nature of the intermolecular bonding at a single molecule-pair level. The distinct time domain and frequency domain features of tunneling signals were extracted from raw signals of analytes such as amino acids and their enantiomers. The Support Vector Machine (a machine-learning method) was used to do classification and predication based on the signal features generated by analytes, giving over 90% accuracy of separation of up to seven analytes. This opens up a new interface between chemistry and electronics with immediate implications for rapid Peptide/DNA sequencing and molecule identification at single molecule level.

  8. Hanford facility dangerous waste permit application, PUREX storage tunnels

    SciTech Connect

    Price, S.M.

    1997-09-08

    The Hanford Facility Dangerous Waste Permit Application is considered to be a single application organized into a General Information Portion (document number DOE/RL-91-28) and a Unit-Specific Portion. The scope of the Unit-Specific Portion is limited to Part B permit application documentation submitted for individual, operating treatment, storage, and/or disposal units, such as the PUREX Storage Tunnels (this document, DOE/RL-90-24). Both the General Information and Unit-Specific portions of the Hanford Facility Dangerous Waste Permit Application address the content of the Part B permit application guidance prepared by the Washington State Department of Ecology (Ecology 1996) and the US Environmental Protection Agency (40 Code of Federal Regulations 270), with additional information needs defined by the Hazardous and Solid Waste Amendments and revisions of Washington Administrative Code 173-303. For ease of reference, the Washington State Department of Ecology alpha-numeric section identifiers from the permit application guidance documentation (Ecology 1996) follow, in brackets, the chapter headings and subheadings. A checklist indicating where information is contained in the PUREX Storage Tunnels permit application documentation, in relation to the Washington State Department of Ecology guidance, is located in the Contents Section. Documentation contained in the General Information Portion is broader in nature and could be used by multiple treatment, storage, and/or disposal units (e.g., the glossary provided in the General Information Portion). Wherever appropriate, the PUREX Storage Tunnels permit application documentation makes cross-reference to the General Information Portion, rather than duplicating text. Information provided in this PUREX Storage Tunnels permit application documentation is current as of April 1997.

  9. Full-Scale Tunnel (FST)

    NASA Technical Reports Server (NTRS)

    1929-01-01

    Modified propeller and spinner in Full-Scale Tunnel (FST) model. On June 26, 1929, Elton W. Miller wrote to George W. Lewis proposing the construction of a model of the full-scale tunnel. 'The excellent energy ratio obtained in the new wind tunnel of the California Institute of Technology suggests that before proceeding with our full scale tunnel design, we ought to investigate the effect on energy ratio of such factors as: 1. small included angle for the exit cone; 2. carefully designed return passages of circular section as far as possible, without sudden changes in cross sections; 3. tightness of walls. It is believed that much useful information can be obtained by building a model of about 1/16 scale, that is, having a closed throat of 2 ft. by 4 ft. The outside dimensions would be about 12 ft. by 25 ft. in plan and the height 4 ft. Two propellers will be required about 28 in. in diameter, each to be driven by direct current motor at a maximum speed of 4500 R.P.M. Provision can be made for altering the length of certain portions, particularly the exit cone, and possibly for the application of boundary layer control in order to effect satisfactory air flow. This model can be constructed in a comparatively short time, using 2 by 4 framing with matched sheathing inside, and where circular sections are desired they can be obtained by nailing sheet metal to wooden ribs, which can be cut on the band saw. It is estimated that three months will be required for the construction and testing of such a model and that the cost will be approximately three thousand dollars, one thousand dollars of which will be for the motors. No suitable location appears to exist in any of our present buildings, and it may be necessary to build it outside and cover it with a roof.' George Lewis responded immediately (June 27) granting the authority to proceed. He urged Langley to expedite construction and to employ extra carpenters if necessary. Funds for the model came from the FST project

  10. Fermion tunneling beyond semiclassical approximation

    NASA Astrophysics Data System (ADS)

    Majhi, Bibhas Ranjan

    2009-02-01

    Applying the Hamilton-Jacobi method beyond the semiclassical approximation prescribed in R. Banerjee and B. R. Majhi, J. High Energy Phys.JHEPFG1029-8479 06 (2008) 09510.1088/1126-6708/2008/06/095 for the scalar particle, Hawking radiation as tunneling of the Dirac particle through an event horizon is analyzed. We show that, as before, all quantum corrections in the single particle action are proportional to the usual semiclassical contribution. We also compute the modifications to the Hawking temperature and Bekenstein-Hawking entropy for the Schwarzschild black hole. Finally, the coefficient of the logarithmic correction to entropy is shown to be related with the trace anomaly.

  11. Davies Critical Point and Tunneling

    NASA Astrophysics Data System (ADS)

    La, Hoseong

    2012-04-01

    From the point of view of tunneling, the physical meaning of the Davies critical point of a second-order phase transition in the black hole thermodynamics is clarified. At the critical point, the nonthermal contribution vanishes so that the black hole radiation is entirely thermal. It separates two phases: one with radiation enhanced by the nonthermal contribution, the other suppressed by the nonthermal contribution. We show this in both charged and rotating black holes. The phase transition is also analyzed in the cases in which emissions of charges and angular momenta are incorporated.

  12. Stress changes ahead of an advancing tunnel

    USGS Publications Warehouse

    Abel, J.F.; Lee, F.T.

    1973-01-01

    Instrumentation placed ahead of three model tunnels in the laboratory and ahead of a crosscut driven in a metamorphic rock mass detected stress changes several tunnel diameters ahead of the tunnel face. Stress changes were detected 4 diameters ahead of a model tunnel drilled into nearly elastic acrylic, 2??50 diameters ahead of a model tunnel drilled into concrete, and 2 diameters ahead of a model tunnel drilled into Silver Plume Granite. Stress changes were detected 7??50 diameters ahead of a crosscut driven in jointed, closely foliated gneisses and gneissic granites in an experimental mine at Idaho Springs, Colorado. These results contrast markedly with a theoretical elastic estimate of the onset of detectable stress changes at 1 tunnel diameter ahead of the tunnel face. A small compressive stress concentration was detected 2 diameters ahead of the model tunnel in acrylic, 1.25 diameters ahead of the model tunnel in concrete, and 1 diameter ahead of the model tunnel in granite. A similar stress peak was detected about 6 diameters ahead of the crosscut. No such stress peak is predicted from elastic theory. The 3-dimensional in situ stress determined in the field demonstrate that geologic structure controls stress orientations in the metamorphic rock mass. Two of the computed principal stresses are parallel to the foliation and the other principal stress is normal to it. The principal stress orientations vary approximately as the foliation attitude varies. The average horizontal stress components and the average vertical stress component are three times and twice as large, respectively, as those predicted from the overburden load. An understanding of the measured stress field appears to require the application of either tectonic or residual stress components, or both. Laboratory studies indicate the presence of proportionately large residual stresses. Mining may have triggered the release of strain energy, which is controlled by geologic structure. ?? 1973.

  13. Advanced optical position sensors for magnetically suspended wind tunnel models

    NASA Technical Reports Server (NTRS)

    Lafleur, S.

    1985-01-01

    A major concern to aerodynamicists has been the corruption of wind tunnel test data by model support structures, such as stings or struts. A technique for magnetically suspending wind tunnel models was considered by Tournier and Laurenceau (1957) in order to overcome this problem. This technique is now implemented with the aid of a Large Magnetic Suspension and Balance System (LMSBS) and advanced position sensors for measuring model attitude and position within the test section. Two different optical position sensors are discussed, taking into account a device based on the use of linear CCD arrays, and a device utilizing area CID cameras. Current techniques in image processing have been employed to develop target tracking algorithms capable of subpixel resolution for the sensors. The algorithms are discussed in detail, and some preliminary test results are reported.

  14. Nonlinear resonance-assisted tunneling induced by microcavity deformation

    PubMed Central

    Kwak, Hojeong; Shin, Younghoon; Moon, Songky; Lee, Sang-Bum; Yang, Juhee; An, Kyungwon

    2015-01-01

    Noncircular two-dimensional microcavities support directional output and strong confinement of light, making them suitable for various photonics applications. It is now of primary interest to control the interactions among the cavity modes since novel functionality and enhanced light-matter coupling can be realized through intermode interactions. However, the interaction Hamiltonian induced by cavity deformation is basically unknown, limiting practical utilization of intermode interactions. Here we present the first experimental observation of resonance-assisted tunneling in a deformed two-dimensional microcavity. It is this tunneling mechanism that induces strong inter-mode interactions in mixed phase space as their strength can be directly obtained from a separatrix area in the phase space of intracavity ray dynamics. A selection rule for strong interactions is also found in terms of angular quantum numbers. Our findings, applicable to other physical systems in mixed phase space, make the interaction control more accessible. PMID:25759322

  15. Advanced optical position sensors for magnetically suspended wind tunnel models

    NASA Astrophysics Data System (ADS)

    Lafleur, S.

    A major concern to aerodynamicists has been the corruption of wind tunnel test data by model support structures, such as stings or struts. A technique for magnetically suspending wind tunnel models was considered by Tournier and Laurenceau (1957) in order to overcome this problem. This technique is now implemented with the aid of a Large Magnetic Suspension and Balance System (LMSBS) and advanced position sensors for measuring model attitude and position within the test section. Two different optical position sensors are discussed, taking into account a device based on the use of linear CCD arrays, and a device utilizing area CID cameras. Current techniques in image processing have been employed to develop target tracking algorithms capable of subpixel resolution for the sensors. The algorithms are discussed in detail, and some preliminary test results are reported.

  16. MTR MAIN FLOOR. NEUTRON TUNNEL (SPANNED BY STILELIKE STEPS) PROJECTS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MTR MAIN FLOOR. NEUTRON TUNNEL (SPANNED BY STILE-LIKE STEPS) PROJECTS FROM THE SOUTHEAST CORNER OF THE MTR TOWARD SOUTHEAST CORNER OF BUILDING, WHERE SHIELDING BLOCKS BEGIN TO SURROUND THE TUNNEL AS IT NEARS DETECTING INSTRUMENTS NEAR THE BUILDING WALL. GEAR RELATED TO CRYSTAL NEUTRON SPECTROMETER IS IN FOREGROUND SURROUNDED BY SHIELDING. DATA CONSOLES ARE AT MID-LEVEL OF EAST FACE. OTHER WORK PROCEEDS ON TOP OF AND ELSEWHERE AROUND REACTOR. NOTE TOOLS HANGING AGAINST SOUTHEAST CORNER, USED TO CHANGE FUEL ELEMENTS AND OTHER REACTOR ITEMS DURING REFUELING CYCLES. INL NEGATIVE NO. 10439. Unknown Photographer, 4/20/1954 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  17. Hawking radiation due to photon and gravitino tunneling

    NASA Astrophysics Data System (ADS)

    Majhi, Bibhas Ranjan; Samanta, Saurav

    2010-11-01

    Applying the Hamilton-Jacobi method we investigate the tunneling of photon across the event horizon of a static spherically symmetric black hole. The necessity of the gauge condition on the photon field, to derive the semiclassical Hawking temperature, is explicitly shown. Also, the tunneling of photon and gravitino beyond this semiclassical approximation are presented separately. Quantum corrections of the action for both cases are found to be proportional to the semiclassical contribution. Modifications to the Hawking temperature and Bekenstein-Hawking area law are thereby obtained. Using this corrected temperature and Hawking's periodicity argument, the modified metric for the Schwarzschild black hole is given. This corrected version of the metric, up to ℏ order is equivalent to the metric obtained by including one loop back reaction effect. Finally, the coefficient of the leading order correction of entropy is shown to be related to the trace anomaly.

  18. Light induced tunnel effect in CNT-Si photodiode

    NASA Astrophysics Data System (ADS)

    Aramo, C.; Ambrosio, M.; Bonavolontà, C.; Boscardin, M.; Castrucci, P.; Crivellari, M.; De Crescenzi, M.; de Lisio, C.; Fiandrini, E.; Grossi, V.; Maddalena, P.; Passacantando, M.; Santucci, S.; Scarselli, M.; Valentini, A.; Valentino, M.

    2016-07-01

    Negative differential resistance (NDR), for which the current is a decreasing function of the voltage, has been observed in the current-voltage curves of several types of structures. We measured tunnelling current and NDR by illuminating large area heterojunction obtained by growing Multi Wall Carbon Nanotubes on the surface of n-doped Silicon substrate. In the absence of light, the current flow is null until a junction threshold of about 2.4 V is reached, beyond which the dark current flows at room temperature with a very low intensity of few nA. When illuminated, a current of tens nA is observed at a drain voltage of about 1.5 V. At higher voltage the current intensity decreases according to a negative resistance of the order of MΩ. In the following we report details of tunneling photodiode realized and negative resistance characteristics.

  19. Enhancement of tunnel magnetoresistance in magnetic tunnel junction by a superlattice barrier

    SciTech Connect

    Chen, C. H.; Hsueh, W. J.

    2014-01-27

    Tunnel magnetoresistance of magnetic tunnel junction improved by a superlattice barrier composed of alternate layers of a nonmagnetic metal and an insulator is proposed. The forbidden band of the superlattice is used to predict the low transmission range in the superlattice barrier. By forbidding electron transport in the anti-parallel configuration, the tunnel magnetoresistance is enhanced in the superlattice junction. The results show that the tunnel magnetoresistance ratio for a superlattice magnetic tunnel junction is greater than that for traditional single or double barrier junctions.

  20. Virtual Processes and Quantum Tunnelling as Fictions

    ERIC Educational Resources Information Center

    Arthur, Richard T. W.

    2012-01-01

    In this paper it is argued that virtual processes are dispensable fictions. The argument proceeds by a comparison with the phenomenon of quantum tunnelling. Building on an analysis of Levy-Leblond and Balibar, it is argued that, although the phenomenon known as quantum tunnelling certainly occurs and is at the basis of many paradigmatic quantum…

  1. Prediction of swelling rocks strain in tunneling

    NASA Astrophysics Data System (ADS)

    Parsapour, D.; Fahimifar, A.

    2016-05-01

    Swelling deformations leading to convergence of tunnels may result in significant difficulties during the construction, in particular for long term use of tunnels. By extracting an experimental based explicit analytical solution for formulating swelling strains as a function of time and stress, swelling strains are predicted from the beginning of excavation and during the service life of tunnel. Results obtained from the analytical model show a proper agreement with experimental results. This closed-form solution has been implemented within a numerical program using the finite element method for predicting time-dependent swelling strain around tunnels. Evaluating effects of swelling parameters on time-dependent strains and tunnel shape on swelling behavior around the tunnel according to this analytical solution is considered. The ground-support interaction and consequent swelling effect on the induced forces in tunnel lining is considered too. Effect of delay in lining installation on swelling pressure which acting on the lining and its structural integrity, is also evaluated. A MATLAB code of " SRAP" is prepared and applied to calculate all swelling analysis around tunnels based on analytical solution.

  2. Object-Based Attention and Cognitive Tunneling

    ERIC Educational Resources Information Center

    Jarmasz, Jerzy; Herdman, Chris M.; Johannsdottir, Kamilla Run

    2005-01-01

    Simulator-based research has shown that pilots cognitively tunnel their attention on head-up displays (HUDs). Cognitive tunneling has been linked to object-based visual attention on the assumption that HUD symbology is perceptually grouped into an object that is perceived and attended separately from the external scene. The present research…

  3. Scheme for accelerating quantum tunneling dynamics

    NASA Astrophysics Data System (ADS)

    Khujakulov, Anvar; Nakamura, Katsuhiro

    2016-02-01

    We propose a scheme of the exact fast forwarding of standard quantum dynamics for a charged particle. The present idea allows the acceleration of both the amplitude and the phase of the wave function throughout the fast-forward time range and is distinct from that of Masuda and Nakamura [Proc. R. Soc. A 466, 1135 (2010), 10.1098/rspa.2009.0446], which enabled acceleration of only the amplitude of the wave function on the way. We apply the proposed method to the quantum tunneling phenomena and obtain the electromagnetic field to ensure the rapid penetration of wave functions through a tunneling barrier. Typical examples described here are (1) an exponential wave packet passing through the δ -function barrier and (2) the opened Moshinsky shutter with a δ -function barrier just behind the shutter. We elucidate the tunneling current in the vicinity of the barrier and find a remarkable enhancement of the tunneling rate (tunneling power) due to the fast forwarding. In the case of a very high barrier, in particular, we present the asymptotic analysis and exhibit a suitable driving force to recover a recognizable tunneling current. The analysis is also carried out on the exact acceleration of macroscopic quantum tunneling with use of the nonlinear Schrödinger equation, which accommodates a tunneling barrier.

  4. Scanning scene tunnel for city traversing.

    PubMed

    Zheng, Jiang Yu; Zhou, Yu; Milli, Panayiotis

    2006-01-01

    This paper proposes a visual representation named scene tunnel for capturing urban scenes along routes and visualizing them on the Internet. We scan scenes with multiple cameras or a fish-eye camera on a moving vehicle, which generates a real scene archive along streets that is more complete than previously proposed route panoramas. Using a translating spherical eye, properly set planes of scanning, and unique parallel-central projection, we explore the image acquisition of the scene tunnel from camera selection and alignment, slit calculation, scene scanning, to image integration. The scene tunnels cover high buildings, ground, and various viewing directions and have uniformed resolutions along the street. The sequentially organized scene tunnel benefits texture mapping onto the urban models. We analyze the shape characteristics in the scene tunnels for designing visualization algorithms. After combining this with a global panorama and forward image caps, the capped scene tunnels can provide continuous views directly for virtual or real navigation in a city. We render scene tunnel dynamically by view warping, fast transmission, and flexible interaction. The compact and continuous scene tunnel facilitates model construction, data streaming, and seamless route traversing on the Internet and mobile devices.

  5. Scanning scene tunnel for city traversing.

    PubMed

    Zheng, Jiang Yu; Zhou, Yu; Milli, Panayiotis

    2006-01-01

    This paper proposes a visual representation named scene tunnel for capturing urban scenes along routes and visualizing them on the Internet. We scan scenes with multiple cameras or a fish-eye camera on a moving vehicle, which generates a real scene archive along streets that is more complete than previously proposed route panoramas. Using a translating spherical eye, properly set planes of scanning, and unique parallel-central projection, we explore the image acquisition of the scene tunnel from camera selection and alignment, slit calculation, scene scanning, to image integration. The scene tunnels cover high buildings, ground, and various viewing directions and have uniformed resolutions along the street. The sequentially organized scene tunnel benefits texture mapping onto the urban models. We analyze the shape characteristics in the scene tunnels for designing visualization algorithms. After combining this with a global panorama and forward image caps, the capped scene tunnels can provide continuous views directly for virtual or real navigation in a city. We render scene tunnel dynamically by view warping, fast transmission, and flexible interaction. The compact and continuous scene tunnel facilitates model construction, data streaming, and seamless route traversing on the Internet and mobile devices. PMID:16509375

  6. Tunnelling from non-localised initial states

    NASA Technical Reports Server (NTRS)

    Bowcock, Peter; Gregory, Ruth

    1991-01-01

    An approach for calculating tunneling amplitudes from a nonlocalized initial state is presented. Generalizing the matching conditions and equations of motion to allow for complex momentum permits a description of tunneling in the presence of so-called classical motion. Possible applications of the method are presented.

  7. Characteristics, causes and control measures of disasters for the soft-rock tunnels in the Wenchuan seismic regions

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Li, Tianbin; He, Chuan; Zhou, Yi

    2016-08-01

    The Guang(yuan)-Gan(su) Expressway is located in the core areas where the Wenchuan earthquake occurred. The surrounding soft-rocks of several tunnels in this region, such as the Dujiashan and Yangjiashan tunnels, are mainly broken into phyllites due to the severe action of the earthquake. Through analyzing the effects of large deformations, lining damage and collapses, which happen frequently in the soft-rock tunnels in the Guang-Gan Expressway, the characteristics and causes of such geological disasters are obtained. It is demonstrated that the large deformation and collapse occur near the vault and tunnel face. The poor mechanical properties and weak self-bearing capacity of the surrounding rock and the softening caused by groundwater are important contributing factors to these disasters. The lack of experience in the design and construction of tunnels in the meizoseismal area, as well as the aftershocks are other important factors to consider. Field test results indicate that the three-bench and the reserved core soil construction method should be applied to control the stability of broken phyllite tunnels, and that this key technology should be strictly controlled during its construction. In particular, increasing the stiffness of the supporting structure and enclosing of the lining in time are efficient methods to control large deformations and collapses in soft-rock tunnels in the meizoseismal area.

  8. Characteristics, causes and control measures of disasters for the soft-rock tunnels in the Wenchuan seismic regions

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Li, Tianbin; He, Chuan; Zhou, Yi

    2016-08-01

    The Guang(yuan)–Gan(su) Expressway is located in the core areas where the Wenchuan earthquake occurred. The surrounding soft-rocks of several tunnels in this region, such as the Dujiashan and Yangjiashan tunnels, are mainly broken into phyllites due to the severe action of the earthquake. Through analyzing the effects of large deformations, lining damage and collapses, which happen frequently in the soft-rock tunnels in the Guang–Gan Expressway, the characteristics and causes of such geological disasters are obtained. It is demonstrated that the large deformation and collapse occur near the vault and tunnel face. The poor mechanical properties and weak self-bearing capacity of the surrounding rock and the softening caused by groundwater are important contributing factors to these disasters. The lack of experience in the design and construction of tunnels in the meizoseismal area, as well as the aftershocks are other important factors to consider. Field test results indicate that the three-bench and the reserved core soil construction method should be applied to control the stability of broken phyllite tunnels, and that this key technology should be strictly controlled during its construction. In particular, increasing the stiffness of the supporting structure and enclosing of the lining in time are efficient methods to control large deformations and collapses in soft-rock tunnels in the meizoseismal area.

  9. Enhancing metal-insulator-insulator-metal tunnel diodes via defect enhanced direct tunneling

    SciTech Connect

    Alimardani, Nasir; Conley, John F.

    2014-08-25

    Metal-insulator-insulator-metal tunnel diodes with dissimilar work function electrodes and nanolaminate Al{sub 2}O{sub 3}-Ta{sub 2}O{sub 5} bilayer tunnel barriers deposited by atomic layer deposition are investigated. This combination of high and low electron affinity insulators, each with different dominant conduction mechanisms (tunneling and Frenkel-Poole emission), results in improved low voltage asymmetry and non-linearity of current versus voltage behavior. These improvements are due to defect enhanced direct tunneling in which electrons transport across the Ta{sub 2}O{sub 5} via defect based conduction before tunneling directly through the Al{sub 2}O{sub 3}, effectively narrowing the tunnel barrier. Conduction through the device is dominated by tunneling, and operation is relatively insensitive to temperature.

  10. Tunnel Magnetoresistance and Temperature Related Effects in Magnetic Tunnel Junctions with Embedded Nanoparticles

    NASA Astrophysics Data System (ADS)

    Useinov, Arthur; Lai, Chih-Huang

    2016-02-01

    Temperature dependence of the tunnel magnetoresistance (TMR) was calculated in range of the quantum-ballistic model in the magnetic tunnel junction (MTJ) with embedded nanoparticles (NPs). The electron tunnel transport through NP was simulated in range of double barrier approach, which was integrated into the model of the magnetic point-like contact. The resonant TMR conditions and temperature impact were explored in detail. Moreover, the possible reasons of the temperature induced resonant conditions were discussed in the range of the lead-tunneling cell (TC)-lead model near Kondo temperature. We also found that redistribution of the voltage drop becomes crucial in this model. Furthermore, the direct tunneling plays the dominant role and cannot be omitted in the quantum systems with the total tunneling thickness up to 5-6nm. Hence, Coulomb blockade model cannot explain Kondo-induced TMR anomalies in nanometer-sized tunnel junctions.

  11. Hydrogen Tunneling in Enzyme Reactions

    NASA Astrophysics Data System (ADS)

    Cha, Yuan; Murray, Christopher J.; Klinman, Judith P.

    1989-03-01

    Primary and secondary protium-to-tritium (H/T) and deuterium-to-tritium (D/T) kinetic isotope effects for the catalytic oxidation of benzyl alcohol to benzaldehyde by yeast alcohol dehydrogenase (YADH) at 25 degrees Celsius have been determined. Previous studies showed that this reaction is nearly or fully rate limited by the hydrogen-transfer step. Semiclassical mass considerations that do not include tunneling effects would predict that kH/kT = (kD/kT)3.26, where kH, kD, and kT are the rate constants for the reaction of protium, deuterium, and tritium derivatives, respectively. Significant deviations from this relation have now been observed for both primary and especially secondary effects, such that experimental H/T ratios are much greater than those calculated from the above expression. These deviations also hold in the temperature range from 0 to 40 degrees Celsius. Such deviations were previously predicted to result from a reaction coordinate containing a significant contribution from hydrogen tunneling.

  12. Hydrogen tunneling in enzyme reactions.

    PubMed

    Cha, Y; Murray, C J; Klinman, J P

    1989-03-10

    Primary and secondary protium-to-tritium (H/T) and deuterium-to-tritium (D/T) kinetic isotope effects for the catalytic oxidation of benzyl alcohol to benzaldehyde by yeast alcohol dehydrogenase (YADH) at 25 degrees Celsius have been determined. Previous studies showed that this reaction is nearly or fully rate limited by the hydrogen-transfer step. Semiclassical mass considerations that do not include tunneling effects would predict that kH/kT = (kD/kT)3.26, where kH, kD, and kT are the rate constants for the reaction of protium, deuterium, and tritium derivatives, respectively. Significant deviations from this relation have now been observed for both primary and especially secondary effects, such that experimental H/T ratios are much greater than those calculated from the above expression. These deviations also hold in the temperature range from 0 to 40 degrees Celsius. Such deviations were previously predicted to result from a reaction coordinate containing a significant contribution from hydrogen tunneling.

  13. Full-Scale Tunnel (FST)

    NASA Technical Reports Server (NTRS)

    1931-01-01

    Wing and nacelle set-up in Full-Scale Tunnel (FST). The NACA conducted drag tests in 1931 on a P3M-1 nacelle which were presented in a special report to the Navy. Smith DeFrance described this work in the report's introduction: 'Tests were conducted in the full-scale wind tunnel on a five to four geared Pratt and Whitney Wasp engine mounted in a P3M-1 nacelle. In order to simulate the flight conditions the nacelle was assembled on a 15-foot span of wing from the same airplane. The purpose of the tests was to improve the cooling of the engine and to reduce the drag of the nacelle combination. Thermocouples were installed at various points on the cylinders and temperature readings were obtained from these by the power plants division. These results will be reported in a memorandum by that division. The drag results, which are covered by this memorandum, were obtained with the original nacelle condition as received from the Navy with the tail of the nacelle modified, with the nose section of the nacelle modified, with a Curtiss anti-drag ring attached to the engine, with a Type G ring developed by the N.A.C.A., and with a Type D cowling which was also developed by the N.A.C.A.' (p. 1)

  14. Evaluating the laws defining blindness.

    PubMed

    Hoppe, E

    1992-06-01

    The law defining legal blindness was written in 1935, and has not been updated since. A historical view of the background in the development of this law and a comparison to laws used in other countries helps to point out some problems with the current definition. As the population gets older, the prevalence of visual impairment will be increasing. To administer programs, distribute funding, and ensure adequate care, the problems inherent in the definition of legal blindness must be addressed, and the law must be revised. PMID:1634739

  15. PUREX Storage Tunnels dangerous waste permit application

    SciTech Connect

    Not Available

    1990-09-01

    The Hanford Site is operated by the US Department of Energy-Richland Operations Office. The PUREX Storage Tunnels are a storage unit located on the Hanford Site. The unit consists of two earth-covered railroad tunnels that are used for storage of process equipment (some containing dangerous waste) removed from the PUREX Plant. Radioactively contaminated equipment is loaded on railroad cars and remotely transferred into the tunnels for long-term storage. Westinghouse Hanford Company is a major contractor to the US Department of Energy-Richland Operations Office and serves as a co-operator of the PUREX Storage Tunnels, the waste management unit addressed by this permit application. This appendix contains Tunnel 1 Construction Specifications, HWS-5638, consisting of 49 pages.

  16. Aberrant Radial Artery Causing Carpal Tunnel Syndrome

    PubMed Central

    Kokkalis, Zinon T.; Tolis, Konstantinos E.; Megaloikonomos, Panayiotis D.; Panagopoulos, Georgios N.; Igoumenou, Vasilios G.; Mavrogenis, Andreas F.

    2016-01-01

    Anatomical vascular variations are rare causes of carpal tunnel syndrome. An aberrant medial artery is the most common vascular variation, while an aberrant radial artery causing carpal tunnel syndrome is even more rare, with an incidence ranging less than 3%. This article reports a patient with compression of the median nerve at the carpal tunnel by an aberrant superficial branch of the radial artery. An 80- year- old man presented with a 5-year history of right hand carpal tunnel syndrome; Tinel sign, Phalen test and neurophysiological studies were positive. Open carpal tunnel release showed an aberrant superficial branch of the radial artery with its accompanying veins running from radially to medially, almost parallel to the median nerve, ending at the superficial palmar arterial arch. The median nerve was decompressed without ligating the aberrant artery. At the last follow-up, 2 years after diagnosis and treatment the patient is asymptomatic. PMID:27517078

  17. Aberrant Radial Artery Causing Carpal Tunnel Syndrome.

    PubMed

    Kokkalis, Zinon T; Tolis, Konstantinos E; Megaloikonomos, Panayiotis D; Panagopoulos, Georgios N; Igoumenou, Vasilios G; Mavrogenis, Andreas F

    2016-06-01

    Anatomical vascular variations are rare causes of carpal tunnel syndrome. An aberrant medial artery is the most common vascular variation, while an aberrant radial artery causing carpal tunnel syndrome is even more rare, with an incidence ranging less than 3%. This article reports a patient with compression of the median nerve at the carpal tunnel by an aberrant superficial branch of the radial artery. An 80- year- old man presented with a 5-year history of right hand carpal tunnel syndrome; Tinel sign, Phalen test and neurophysiological studies were positive. Open carpal tunnel release showed an aberrant superficial branch of the radial artery with its accompanying veins running from radially to medially, almost parallel to the median nerve, ending at the superficial palmar arterial arch. The median nerve was decompressed without ligating the aberrant artery. At the last follow-up, 2 years after diagnosis and treatment the patient is asymptomatic.

  18. Aberrant Radial Artery Causing Carpal Tunnel Syndrome.

    PubMed

    Kokkalis, Zinon T; Tolis, Konstantinos E; Megaloikonomos, Panayiotis D; Panagopoulos, Georgios N; Igoumenou, Vasilios G; Mavrogenis, Andreas F

    2016-06-01

    Anatomical vascular variations are rare causes of carpal tunnel syndrome. An aberrant medial artery is the most common vascular variation, while an aberrant radial artery causing carpal tunnel syndrome is even more rare, with an incidence ranging less than 3%. This article reports a patient with compression of the median nerve at the carpal tunnel by an aberrant superficial branch of the radial artery. An 80- year- old man presented with a 5-year history of right hand carpal tunnel syndrome; Tinel sign, Phalen test and neurophysiological studies were positive. Open carpal tunnel release showed an aberrant superficial branch of the radial artery with its accompanying veins running from radially to medially, almost parallel to the median nerve, ending at the superficial palmar arterial arch. The median nerve was decompressed without ligating the aberrant artery. At the last follow-up, 2 years after diagnosis and treatment the patient is asymptomatic. PMID:27517078

  19. Carpal tunnel syndrome among ski manufacturing workers.

    PubMed

    Barnhart, S; Demers, P A; Miller, M; Longstreth, W T; Rosenstock, L

    1991-02-01

    Carpal tunnel syndrome is a common disorder marked by pain and dysesthesias of the upper extremities. As a test of the hypothesis that carpal tunnel syndrome is associated with occupational risk factors, jobs at a ski assembly plant were classified as repetitive and nonrepetitive. The prevalence of carpal tunnel syndrome among 106 employees with repetitive jobs was compared with that among 67 employees with nonrepetitive jobs. The data collection included a questionnaire, a physical examination, and the measurement of distal sensory latencies of the median and ulnar nerves. Carpal tunnel syndrome was present in either or both hands in 15.4% of those workers with repetitive jobs, but only in 3.1% of those workers with nonrepetitive jobs (crude prevalence ratio 4.92, 95% confidence interval 1.17-20.7). The conclusion was drawn that carpal tunnel syndrome is associated with jobs requiring frequent and sustained hand work.

  20. Design of air curtains used for area confinement in tunnels

    NASA Astrophysics Data System (ADS)

    Guyonnaud, L.; Solliec, C.; Dufresne de Virel, M.; Rey, C.

    Air curtains' devices, i.e., plane air jets, are used as virtual screens to reduce the heat and mass transfer from one zone to another subjected to different environmental or climatic conditions. An air curtain is a plane air jet blown through an opening. It produces a pressure drop that forbids transversal flow through the opening. The principal advantage of such installations is to facilitate the transit of people, vehicles or material through doorways of buildings and other enclosures. The purpose of this research is twofold: (i) to characterize the efficiency of air curtains; (ii) to establish how scaled down models could be used to set up full-scale installations.