Sample records for excavation and tunneling

  1. New drainage tunnel of the tunnel Višňové - design and excavation (United States)

    Jurík, Igor; Grega, Ladislav; Valko, Jozef; Janega, Peter


    The actual pilot tunnel dated to the period of geological and hydrogeological survey, is designed as a part of the tunnel Višňové, which is located at the section of the D1 motorway Lietavská Lúčka - Višňové - Dubná Skala in Slovakia. Drainage tunnel will be used for the drainage of the main tunnel tubes, where the maximum inflow from the eastern portal is greater than 250 l.s-1. Overlapping of the initial pilot tunnel with the profile of the southern tunnel tube led to the demolition of the portal sections of the pilot tunnel during the excavation of main tunnel tubes. These sections were replaced by new drainage tunnels, with the lengths of 288.0 meters from west portal and 538.0 meters from eastern portal, to ensure access from both portals. The new drainage tunnel is excavated under the level of the two main tunnel tubes. Drainage pipes with a diameter of 250 mm will be installed from cleaning niches in the main tunnel tubes to the new drainage tunnel.

  2. ZEDEX - A study of damage and disturbance from tunnel excavation by blasting and tunnel boring

    Energy Technology Data Exchange (ETDEWEB)

    Emsley, S. [Golder Associates, Maidenhead (United Kingdom); Olsson, Olle; Stenberg, L. [Swedish Nuclear Fuel and Waste Co., Figeholm (Sweden); Alheid, H.J. [Federal Inst. for Geosciences and Natural Resources, Hannover (Germany); Falls, S. [Queens Univ., Kingston, ON (Canada)


    The objectives of the ZEDEX project were to understand the mechanical behaviour of the excavation disturbed zone (EDZ) with respect to its origin, character, magnitude of property change, extent and its dependence on excavation method. Excavation with normal smooth blasting, blasting with low shock explosives and tunnel boring were studied. The drifts are located at Aespoe at a depth of 420 m, the profiles are circular and 5 m in diameter. The results have shown that there is a damaged zone, close to the drift wall dominated by changes in rock properties which are irreversible, and that there is a disturbed zone beyond the damaged zone that is dominated by changes in stress state and mainly reversible. There is no distinct boundary between the two zones. The results from ZEDEX indicate that the role of the EDZ as a preferential pathway to radionuclide transport is limited to the damaged zone. The extent of the damaged zone can be limited through application of appropriate excavation methods. By limiting the extent of the damaged zone it should also be feasible to block pathways in the damaged zone by plugs placed at strategic locations 68 refs, 92 figs, 31 tabs

  3. Geological Investigation and Tunnel Excavation Aspects of the Weakness Zones of Xiang'an Subsea Tunnels in China (United States)

    Shi, Peixin; Zhang, Dingli; Pan, Jianli; Liu, Wei


    Tunneling through weakness zones under deep seawater involves significant risks and may have disastrous consequences. This paper presents a case study of geological investigation and excavation aspects of subsea tunnels in major weakness zones. The subject is the Xiang'an subsea tunnels, the first subsea tunnel project in mainland China. The Xiang'an subsea tunnels passed through four major weakness zones, mainly consisting of highly to completely weathered rock mass. The weakness zones were characterized by a combination of long-distance and short-distance, destructive and nondestructive methods, which supplement and verify information with each other. The weakness zones were treated by full-face curtain grouting, using both cementitious and chemical grouts. The interrelationship between the settlement at tunnel crown and ground surface, as well as the interrelationship between ground settlement and ground cracking, were explored based on instrumentation data recorded during tunneling on land. The pre-warning, warning, and limiting values of tunnel crown settlement during excavation of each heading of subsea sections were established to protect the seabed against cracking. Engineering means and methods were developed to control the ground deformation during excavation.

  4. Three-Dimensional Laser Scanning for Geometry Documentation and Construction Management of Highway Tunnels during Excavation

    Directory of Open Access Journals (Sweden)

    Vassilis Gikas


    Full Text Available Driven by progress in sensor technology, computer software and data processing capabilities, terrestrial laser scanning has recently proved a revolutionary technique for high accuracy, 3D mapping and documentation of physical scenarios and man-made structures. Particularly, this is of great importance in the underground space and tunnel construction environment as surveying engineering operations have a great impact on both technical and economic aspects of a project. This paper discusses the use and explores the potential of laser scanning technology to accurately track excavation and construction activities of highway tunnels. It provides a detailed overview of the static laser scanning method, its principles of operation and applications for tunnel construction operations. Also, it discusses the planning, execution, data processing and analysis phases of laser scanning activities, with emphasis given on geo-referencing, mesh model generation and cross-section extraction. Specific case studies are considered based on two construction sites in Greece. Particularly, the potential of the method is examined for checking the tunnel profile, producing volume computations and validating the smoothness/thickness of shotcrete layers at an excavation stage and during the completion of excavation support and primary lining. An additional example of the use of the method in the geometric documentation of the concrete lining formwork is examined and comparisons against dimensional tolerances are examined. Experimental comparisons and analyses of the laser scanning method against conventional surveying techniques are also considered.

  5. Three-dimensional laser scanning for geometry documentation and construction management of highway tunnels during excavation. (United States)

    Gikas, Vassilis


    Driven by progress in sensor technology, computer software and data processing capabilities, terrestrial laser scanning has recently proved a revolutionary technique for high accuracy, 3D mapping and documentation of physical scenarios and man-made structures. Particularly, this is of great importance in the underground space and tunnel construction environment as surveying engineering operations have a great impact on both technical and economic aspects of a project. This paper discusses the use and explores the potential of laser scanning technology to accurately track excavation and construction activities of highway tunnels. It provides a detailed overview of the static laser scanning method, its principles of operation and applications for tunnel construction operations. Also, it discusses the planning, execution, data processing and analysis phases of laser scanning activities, with emphasis given on geo-referencing, mesh model generation and cross-section extraction. Specific case studies are considered based on two construction sites in Greece. Particularly, the potential of the method is examined for checking the tunnel profile, producing volume computations and validating the smoothness/thickness of shotcrete layers at an excavation stage and during the completion of excavation support and primary lining. An additional example of the use of the method in the geometric documentation of the concrete lining formwork is examined and comparisons against dimensional tolerances are examined. Experimental comparisons and analyses of the laser scanning method against conventional surveying techniques are also considered.

  6. Airborne asbestos fibres monitoring in tunnel excavation. (United States)

    Gaggero, Laura; Sanguineti, Elisa; Yus González, Adrián; Militello, Gaia Maria; Scuderi, Alberto; Parisi, Giovanni


    Tunnelling across ophiolitic formation with Naturally Occurring Asbestos (NOA) can release fibres into the environment, exposing workers, and the population, if fibres spread outside the tunnel, leading to increased risk of developing asbestos-related disease. Therefore, a careful plan of environmental monitoring is carried out during Terzo Valico tunnel excavation. In the present study, data of 1571 samples of airborne dust, collected between 2014 and 2016 inside the tunnels, and analyzed by SEM-EDS for quantification of workers exposure, are discussed. In particular, the engineering and monitoring management of 100 m tunnelling excavation across a serpentinite lens (Cravasco adit), intercalated within calcschists, is reported. At this chrysotile occurrence, 84% of 128 analyzed samples (from the zone closer to the front rock) were above 2 ff/l. However, thanks to safety measures implemented and tunnel compartmentation in zones, the asbestos fibre concentration did not exceed the Italian standard of occupational exposure (100 ff/l) and 100% of samples collected in the outdoor square were below 1 ff/l. During excavation under normal working conditions, asbestos concentrations were below 2 ff/l in 97.4% of the 668 analyzed samples. Our results showed that air monitoring can objectively confirm the presence of asbestos minerals at a rock front in relative short time and provide information about the nature of the lithology at the front. The present dataset, the engineering measures described and the operative conclusions are liable to support the improvement of legislation on workers exposure to asbestos referred to the tunnelling sector, lacking at present. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Various Tunnel Excavation Methods used on the LHC Project

    CERN Document Server

    Fielder, R


    Civil Engineering construction work for the LHC Project began in April 1998 and is now well underway. A major part of this work is the construction of the new tunnels, caverns and cavern enlargements for the LHC experiments and machine. Currently, this underground work is being carried out for the two injection tunnels, TI2 and TI8, and at Point 1 for the Atlas Experiment. There are three contractors involved in these tunnelling works and each contactor is using a different technique. This paper will outline the different methods used for excavation and the reasons for these differences. It will also examine the other operations involved in the construction of major underground structures such as supply of materials to the tunnel face, evacuation of excavated material and ventilation.


    Directory of Open Access Journals (Sweden)

    Hrvoje Antičević


    Full Text Available Design of underground spaces, including tunnels, and repositories for radioactive waste include the application of the same or similar technologies. Tunnel excavation by blasting inevitably results in the damage in the rock mass around the excavation profile. The damage in the rock mass immediately next to the tunnel profile emerges as the expanding of the existing cracks and the appearance of new cracks, i.e. as the change of the physical and-mechanical properties of the rock mass. Concerning the design of deep geological repositories, requirements in terms of damaged rock are the same or more rigorous than for the design of tunnel. The aforementioned research is directed towards determining the depth of damage zone caused by blasting. The depth of the damage zone is determined by measuring the changes of physical and-mechanical properties of the rock mass around the tunnel excavation profile. By this research the drilling and blasting parameters were correlated with the depth and size of the damage zone (the paper is published in Croatian.

  9. Forecasting and prevention of water inrush during the excavation process of a diversion tunnel at the Jinping II Hydropower Station, China. (United States)

    Hou, Tian-Xing; Yang, Xing-Guo; Xing, Hui-Ge; Huang, Kang-Xin; Zhou, Jia-Wen


    Estimating groundwater inflow into a tunnel before and during the excavation process is an important task to ensure the safety and schedule during the underground construction process. Here we report a case of the forecasting and prevention of water inrush at the Jinping II Hydropower Station diversion tunnel groups during the excavation process. The diversion tunnel groups are located in mountains and valleys, and with high water pressure head. Three forecasting methods are used to predict the total water inflow of the #2 diversion tunnel. Furthermore, based on the accurate estimation of the water inrush around the tunnel working area, a theoretical method is presented to forecast the water inflow at the working area during the excavation process. The simulated results show that the total water flow is 1586.9, 1309.4 and 2070.2 m(3)/h using the Qshima method, Kostyakov method and Ochiai method, respectively. The Qshima method is the best one because it most closely matches the monitoring result. According to the huge water inflow into the #2 diversion tunnel, reasonable drainage measures are arranged to prevent the potential disaster of water inrush. The groundwater pressure head can be determined using the water flow velocity from the advancing holes; then, the groundwater pressure head can be used to predict the possible water inflow. The simulated results show that the groundwater pressure head and water inflow re stable and relatively small around the region of the intact rock mass, but there is a sudden change around the fault region with a large water inflow and groundwater pressure head. Different countermeasures are adopted to prevent water inrush disasters during the tunnel excavation process. Reasonable forecasting the characteristic parameters of water inrush is very useful for the formation of prevention and mitigation schemes during the tunnel excavation process.

  10. Hydraulic Features of the Excavation Disturbed Zone - Laboratory investigations of samples taken from the Q- and S-tunnels at Aespoe HRL

    Energy Technology Data Exchange (ETDEWEB)

    Ericsson, Lars O.; Brinkhoff, Petra; Gustafson, Gunnar; Kvartsberg, Sara (Div. of GeoEngineering, Dept. of Civil and Environmental Engineering, Chalmers Univ. of Technology, Goeteborg (Sweden))


    The general aim of the project has been to contribute to the SKB safety and assessment analysis with realistic figures of hydraulic properties in an excavation disturbed zone. The project had the following more detailed objectives: - Develop a laboratory method to determine fracture transmissivity under water-saturated conditions. - Provide magnitudes for realistic values for fracture transmissivity in the disturbed or damaged zone due to excavation. - Map micro cracks radially from the tunnel wall. - Map the spread of matrix porosity radially from the tunnel wall. - Develop single-hole hydraulic testing methodology in tunnel wall for saturated conditions. - Integration of fracture geometries and transmissivity investigations for conceptual hydraulic modelling of the bedrock along a tunnel wall

  11. Hierarchical stochastic model of terrain subsidence during tunnel excavation (United States)

    Janda, Tomáš; Šejnoha, Jiří; Šejnoha, Michal


    In this contribution the Bayesian statistical method is applied to assess the expected probability distribution of the terrain subsidence in the course of tunnel excavation. The approach utilizes a number of simplifying assumptions regarding the system kinematics to arrive at a very simple model with just a few degrees of freedom. This deterministic model together with the intrinsic uncertainties of its parameters and measurement inaccuracies are used to formulate the stochastic model which defines a distribution of the predicted values of terrain subsidence. Assuming the measured data to be fixed, the stochastic model thus defines the likelihood function of the model parameters which is directly used for updating their prior distribution. This way the model parameters can be incrementally updated with each excavation step and the prediction of the model refined.

  12. CRIEPI and SKB cooperation report No. 4. Numerical analysis for the effect of tunnel excavation on groundwater flow at Aespoe Hard Rock Laboratory, Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Yasuharu; Miyakawa, Kimio; Igarashi; Toshifumi [Central Research Inst. of Electric Power Industry, Abiko, Chiba (Japan). Abiko Research Lab


    A numerical analysis was performed for the hydraulic impact of the tunnel excavated in crystalline rock for the construction of an underground research laboratory at Aespoe Island in Sweden. The subject of this study is to clarify the influence of excavation of the tunnel section from 700 m to 2,545 m. The size of the modeled region for the analysis is 1,800 meters from east to west and 2,000 meters from north to south so that it includes all the area of Aespoe Island. The lower boundary of the model is 1,000 meters under the ground. The existence of 19 major fracture zones was confirmed through geological survey and values of transmissivity, storativity and width were assigned to the fracture zones individually in the numerical model. On the other hand, uniform hydraulic characteristics were assigned to the whole rock formation except the fracture zones. Reduction of the hydraulic conductivities was taken into account for the grouted fracture zones. The analysis was performed by using a numerical code, FEGM, developed by CRIEPI for three-dimensional groundwater flow analysis. Drawdowns were observed during tunnel excavation at the boreholes excavated from the ground surface in Aespoe Island and were compared with the calculated results. The calculated drawdowns agreed will with the observed ones, indicating that the analytical method was proved effective. (author)

  13. Relevant risk factors associated with the construction of excavated tunnel cross-passages in soft soils

    NARCIS (Netherlands)

    Chivatá Cárdenas, Ibsen; Al-Jibouri, Saad H.S.; Halman, Johannes I.M.


    This paper reports on an investigation of risk factors associated with the construction of excavated tunnel cross-passages in soft soils. The investigation focused on excavations where freezing technologies are used to provide temporary support. The relevant risk factors and their associated

  14. 3D Modelling of a Tunnel Re-excavation in Soft Ground

    Directory of Open Access Journals (Sweden)

    M. Hilar


    Full Text Available The construction of the shallow tunnel at Brezno started using the Pre-Vault Method. The tunnel excavation, in complicated geological conditions, led to many difficulties which finally resulted in a collapse, when a significant part of the temporary tunnel lining collapsed. Various options for re-excavating the tunnel were evaluated prior to further construction. Finally a decision was made to separate the collapsed area into sections 9 m in length using 16 m-wide, transversally oriented pile walls, to improve the stability of the collapsed ground. The walls were constructed from the surface prior to excavation. It was also decided to re-excavate a collapsed area using the Sprayed Concrete Lining (SCL method. Due to problematic soft ground conditions, which had been made even worse by the collapse, some additional support measures had to be considered prior to re-excavation (ground improvement, micropile umbrellas embedded into the pile walls, etc.This paper describes numerical modelling of the tunnel re-excavation through the collapsed area. Initial calculations of the tunnel re-excavation were made using a 2D finite element method. Subsequently, further calculations to evaluate the rock mass behaviour in the collapsed area were provided in 3D. The 2D calculations were used to provide sensitivity studies, while 3D modelling was mainly used for evaluating the tunnel face stability (impact of the pile walls, impact of ground improvement together with other factors (length of advances, moment of the temporary invert closure, etc. The results of the modelling were compared with the monitoring results.The paper also briefly describes the construction experience (technical problems, performance of various support measures, etc. The excavation and the primary lining construction were completed in 2006, and the tunnel was opened for traffic in April 2007.

  15. Full-face excavation of large tunnels in difficult conditions

    Directory of Open Access Journals (Sweden)

    Giovanni Barla


    Full Text Available Following a few preliminary remarks on the tunneling methods at the beginning of the 20th century, the successful applications of the full-face method also in difficult conditions are underlined. The attention is posed on the use of a systematic reinforcement of the face and of the ground, by means of fiber-glass elements. A selection of tunnels where this method was used successfully is reported with the purpose of illustrating the wide spectrum of ground conditions where it has been applied. Then, following a description of the main concepts behind the method, the attention moves from the so-called “heavy method”, where deformations are restrained, to the “light method”, where deformations are allowed with the intention to decrease the stresses acting on the primary and final linings. The progress in the application of the “light method” is underlined, up to the development of a novel technique, which relies on the use of a yielding support composed of top head steel sets with sliding joints and special deformable elements inserted in the primary lining. The well-known case study of the Saint Martin La Porte access adit, along the Lyon-Turin Base Tunnel, is described. In this tunnel, a yield-control support system combined with full-face excavation has been adopted successfully in order to cope with the large deformations experienced during face advance through the Carboniferous formation. The monitoring results obtained during excavation are illustrated, together with the modeling studies performed when paying attention to the rock mass time-dependent behavior.

  16. Mechanical analysis about the influence of tunnel excavation on vertical effect of adjacent bridge pile (United States)

    Tian, Xiaoyan


    Tunnel excavation will bring additional deformation and internal force of adjacent bridge piles, if the deformation is large, it will threat the upper structure safety of the bridge. According to the complexity of the existing three - dimensional numerical simulation modeling and the time - consuming calculation, a two - stage analysis method of tunnel excavation based on Winkler foundation model was proposed. Firstly, Loganathan and Polous solutions were used to obtain the vertical displacement of the soil free field at the pile position when tunnel excavated, and the corresponding polynomial fitting displacement curve was taken. Secondly, the differential equation was established by means of the equilibrium condition of micro - element physical force and considering the pile group effect. Then, through the logical derivation, the calculation expressions of the tunnel excavation on the effect of the adjacent bridge pile (settlement, axial force and friction resistance) were obtained. Finally, based on the background of the tunnel project of Yanxing Door Station ∼ Xianning Road Station in Xi’an Metro Line 3, the feasibility and applicability of the proposed method were proved by comparing the calculated values with the numerical simulation values. It provides theoretical guidance for the effective analysis about the influence of tunnel excavation on the adjacent pile foundation effect.

  17. Our experience with the full-profile excavation of exploratory for tunnel pipes

    Directory of Open Access Journals (Sweden)

    Edita Lazarová


    Full Text Available The economic development of Slovakia places an emphasis on increasing the quality of transport infrastructure, which requires its modernization residing in building the transport network of international level and improving its efficiency and travel speed. The development of transport in Slovakia has been passing major changes related to the economic and political processes in the country. Regarding the geographical character of the land, the tunnel excavation is an inseparable feature of the road communications modernization. Approximately thirty kilometres of highway tunnels are planned for construction in Slovakia until 2020 and road tunnels should be constructed as well. The first modern highway tunnel Branisko, the longest one (4975 m in Slovakia was put into operation in 2003 with a preceding excavation of the Branisko exploratory gallery in the course of designed tunnel pipe. The tunnelling works on the exploratory gallery of Višňové tunnel started in January 1999 and finished in the late summer of 2002 due to unfavorable geological conditions. The excavation of a final profile of the Višňové tunnel is planned for 2007. The Horelica tunnel (605 m near Čadca was finished and put into operation in 2004. The tunnels Lučivná (250 m, Bôrik (999 m and Sitina (1440 m are in construction at present.

  18. Crane and Excavator Operator. (United States)

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on crane and excavator operation is designed to enable the crane and excavator operator to perform his/her duties more proficiently. Introductory materials include specific information for MCI students, a course introduction, and a study guide…

  19. Reduction of excavation face collapse risk in tunnelling. (United States)

    Ariani, Filippo; Baldasseroni, Alberto; Muller, Alessandro; Biffino, Marco; Matteucci, Alessandro


    Two large road tunnels, recently developed near Florence, showed instabilities of the excavation face which subsequently caused sixteen collapses. Due to the risk for workers' safety, the public authority for occupational health and safety (ASL) has monitored the failure rate and other background variables in order to assess the possible correlations between risk reductions, its own actions, and those of the various safety actors involved. To evaluate if the interventions carried out by the design team were able to reduce the risks of collapse and which of the ASL actions and/or which other factors were more effective in changing the attitudes of the parties involved, leading to a more expensive but safer project variant. After adoption of the second of two project variants, no more collapses were observed. No correlation was found between trend of ASL inspections and observed variation of collapse rate. Conversely, the adoption of strongly coercive measures and investigation reporting by local media coincided with periods of risk reduction, even if the low number of events does not allow for statistical evaluation. These findings appear to be coherent with the ratio of the cost of penalties related to health and safety infringements (thousands of euros) to the overall cost of the safer project variant (a hundred times greater).  The safer variant required 7% more labour but avoided forced interruptions caused by the collapses, allowing a 13% faster excavation rate.

  20. Theoretical study of short pile effect in tunnel excavation (United States)

    Tian, Xiao-yan; Liu, Jing; Gao, Xiao-mei; Li, Yuan


    The Misaki Sato Go ideal elastoplastic model is adopted and the two stage analysis theory is used to study the effect of tunnel excavation on short pile effect in this paper. In the first stage, the free field vertical displacement of the soil at the corresponding pile location is obtained by using empirical formula. In the second stage, the displacement is applied to the corresponding pile location. The equilibrium condition of micro physical differential equation settlement of piles. Then through logical deduction and the boundary condition expressions of the settlement calculation, obtain the pile side friction resistance and axial force of the week. Finally, an engineering example is used to analyze the influence of the change of main parameters on their effects.

  1. Seismic Waves Scattering Impact through Tunnel Excavation on Adjacent Monuments Subjected to Far Field Earthquakes

    Directory of Open Access Journals (Sweden)

    Ghobakhloo E.


    Full Text Available The study of the effect of seismic wave scattering has attracted extensive attention in the past couple of decades especially in infrastructures like tunnels. A seismic wave, meeting the tunnel, can generate scattering which, in most cases, may incur damages in adjacent structures. In this study, using Finite Element Method (FEM, the effect of seismic wave scattering in far field has been investigated. The twin tunnels of Shiraz subway system are selected as the case study in this research and three far field seismic waves were chosen for time history analyses. Investigating the normal mode (before tunnel construction in comparison to the excavation mode (after tunnel construction enables calculation of the effect of displacement in adjacent structures. The analysis results indicate there is a significant difference between before and after tunnel construction (P-value<0.05. Accordingly, the influence of constructing a tunnel on adjacent surface structures is very important for tunnel design.

  2. Intelligent Risk Assessment for Dewatering of Metro-Tunnel Deep Excavations

    Directory of Open Access Journals (Sweden)

    X. W. Ye


    Full Text Available In recent years, China has been undergoing a metro railway construction boom in order to alleviate the urban traffic congestion problem resulting from the rapid urbanization and population growth in many metropolises. In the construction of metro systems, deep excavations and continuous dewatering for construction of the metro tunnels and stations remain a challenging and high risk task in densely populated urban areas. Intelligent computational methods and techniques have exhibited the exceptional talent in dealing with the complicated problems inherent in the deep excavation and dewatering practice. In this paper, an intelligent risk assessment system for deep excavation dewatering is developed and has been applied in the project of Hangzhou Metro Line 1 which is the first metro line of the urban rapid rail transit system in Hangzhou, China. The specific characteristics and great challenges in deep excavation dewatering of the metro-tunnel airshaft of Hangzhou Metro Line 1 are addressed. A novel design method based on the coupled three-dimensional flow theory for dewatering of the deep excavation is introduced. The modularly designed system for excavation dewatering risk assessment is described, and the field observations in dewatering risk assessment of the airshaft excavation of Hangzhou Metro Line 1 are also presented.

  3. Theoretical Analysis on the Effect of Tunnel Excavation on Building strip foundation (United States)

    Tian, Xiaoyan; Gu, Shuancheng; Huang, Rongbin


    In this paper, according to the characteristics of the ground settlement troughs curves, the influence of tunnel excavation on the effect of strip foundation was studied by inverse analysis firstly. The differential equation of the synergistic effect of the strip foundation and foundation under the tunnel excavation was established by using the equilibrium condition of the micro-element physical force. Then, the conceptual definite initial parameter method was used to solve the corresponding homogeneous equation. According to the plane section assumption, combined with the basic theory of material mechanics, considering the differential characteristic of hyperbolic trigonometric function, and using matlabmathmatica software, the theoretical calculation expression of displacement and internal force which is about the tunnel passes through the strip foundation was obtained. Finally, combined with engineering case analysis, changes of the relative position between the tunnel and the foundation, the influences of the main parameters on the foundation effect were studied. The results show that: The influence scope of the tunnel on the foundation is [-0.5 ~ 1.5] times of the foundation length, and when the tunnel center at the end of the foundation, there exists the maximum settlement. The parameters about the soil loss rate, the excavation section and the buried depth of the tunnel have great influence on the foundation effect. The change of foundation height has a great influence on its internal force.

  4. Determining the Particle Size of Debris from a Tunnel Boring Machine Through Photographic Analysis and Comparison Between Excavation Performance and Rock Mass Properties (United States)

    Rispoli, A.; Ferrero, A. M.; Cardu, M.; Farinetti, A.


    This paper presents the results of a study carried out on a 6.3-m-diameter exploratory tunnel excavated in hard rock by an open tunnel boring machine (TBM). The study provides a methodology, based on photographic analysis, for the evaluation of the particle size distribution of debris produced by the TBM. A number of tests were carried out on the debris collected during the TBM advancement. In order to produce a parameter indicative of the particle size of the debris, the coarseness index (CI) was defined and compared with some parameters representative of the TBM performance [i.e. the excavation specific energy (SE) and field penetration index (FPI)] and rock mass features, such as RMR, GSI, uniaxial compression strength and joint spacing. The results obtained showed a clear trend between the CI and some TBM performance parameters, such as SE and FPI. On the contrary, due to the rock mass fracturing, a clear relationship between the CI and rock mass characteristics was not found.

  5. Discrete element analysis of the excavation effect of cross-river tunnel on the surroundings

    Directory of Open Access Journals (Sweden)

    Liu Dongyuan


    Full Text Available Cross-river tunnel as one of the underground constructions is complicated during its construction. For stability of tunnel excavation, it is emergency to analyze the dynamic characteristics of tunnel deformation under high water pressure. Therefore, a cross-river tunnel model is proposed based on DEM in this paper. Stiffness of particles decreases during excavation process which is as one of excavation methods. Porosity ratio of original porosity over its value at different excavation time has been considered. Radial displacements of particles at different angle around the tunnel are detected during excavation process. It shows that large deformation occurs at the vault of the excavation zone which accompanies with large radial displacement. The upper half of the tunnel performs larger deformation than the lower half part which results in many cracks in the concrete lining, the high water pressure may play an crucial role in it.

  6. Meaningful use of peak particle velocities at excavation surfaces for the optimisation of the rockburst criteria for tunnels and stopes.

    CSIR Research Space (South Africa)

    Milev, AM


    Full Text Available = angular frequency ψ = potential for S-wave x = site response attenuation 1 1 Introduction 1.1 Motivation In seismic and rockburst-prone mines, sudden fault rupture or the failure of highly strained rock leads to energy being radiated in the form... of seismic waves. The seismic waves interact with mining excavations, leading to interface and surface waves, energy channelling and wave focussing. The rock is subjected to rapid accelerations, resulting in rock-fabric failure, keyblock ejection and stope...

  7. Model uncertainty of various settlement estimation methods in shallow tunnels excavation; case study: Qom subway tunnel (United States)

    Khademian, Amir; Abdollahipour, Hamed; Bagherpour, Raheb; Faramarzi, Lohrasb


    In addition to the numerous planning and executive challenges, underground excavation in urban areas is always followed by certain destructive effects especially on the ground surface; ground settlement is the most important of these effects for which estimation there exist different empirical, analytical and numerical methods. Since geotechnical models are associated with considerable model uncertainty, this study characterized the model uncertainty of settlement estimation models through a systematic comparison between model predictions and past performance data derived from instrumentation. To do so, the amount of surface settlement induced by excavation of the Qom subway tunnel was estimated via empirical (Peck), analytical (Loganathan and Poulos) and numerical (FDM) methods; the resulting maximum settlement value of each model were 1.86, 2.02 and 1.52 cm, respectively. The comparison of these predicted amounts with the actual data from instrumentation was employed to specify the uncertainty of each model. The numerical model outcomes, with a relative error of 3.8%, best matched the reality and the analytical method, with a relative error of 27.8%, yielded the highest level of model uncertainty.

  8. Qajaa Excavations 1981 and 1982

    DEFF Research Database (Denmark)

    Fog Jensen, Jens


    This report is an account of excavations conducted in 1981 and 1982 by Jørgen Meldgaard (1927-2007) The National Museum of Denmark at the Qajaa site in West Greenland. A total of 388 wooden objects, 255 bone artefacts, 696 lithic tools and more than 4000 flakes have been excavated and are presented...

  9. Rock samples from LEP/LHC tunnel excavation

    CERN Multimedia


    Rock samples taken from 0 to 170 m below ground on the CERN site when the LEP (Large Electron Positron collider) pit number 6 was drilled in Bois-chatton (Versonnex). The challenges of LHC civil engineering: A mosaic of works, structures and workers of differents crafts and origins. Three consulting consortia for the engineering and the follow-up of the works. Four industrial consortia for doing the job. A young team of 25 CERN staff, 30 surface buildings, 32 caverns of all sizes, 170 000 m3 of concrete, 420 000 m3 excavated. 1998-2004 : six years of work and 340 millions Swiss Francs.

  10. Discussion on the mechanism of ground improvement method at the excavation of shallow overburden tunnel in difficult ground

    Directory of Open Access Journals (Sweden)

    Kiyoshi Kishida


    Full Text Available Tunnel construction opportunities involving shallow overburdens under difficult (e.g., soft, unconsolidated grounds have been increasing in Japan. Various auxiliary methods for excavating mountain tunnels have been developed and can satisfy stringent construction requirements. The ground improvement method, which is one of the auxiliary methods for shallow overburden tunnels, has demonstrated its ability to effectively control the amount of settlement under soft ground. However, the mechanism of the ground improvement method has not been clarified, nor has a suitable design code been established for it. Therefore, because the strength of the improved ground and the suitable length and width of the improved area have not been fully understood, an empirical design has been applied in every case. In this paper, the mechanical behavior during the excavation, including that of the stabilized ground, is evaluated through trapdoor experiments and numerical analyses. In addition, the enhancement of tunnel stability resulting from the application of the ground improvement method is discussed.

  11. Stability of Large Parallel Tunnels Excavated in Weak Rocks: A Case Study (United States)

    Ding, Xiuli; Weng, Yonghong; Zhang, Yuting; Xu, Tangjin; Wang, Tuanle; Rao, Zhiwen; Qi, Zufang


    Diversion tunnels are important structures for hydropower projects but are always placed in locations with less favorable geological conditions than those in which other structures are placed. Because diversion tunnels are usually large and closely spaced, the rock pillar between adjacent tunnels in weak rocks is affected on both sides, and conventional support measures may not be adequate to achieve the required stability. Thus, appropriate reinforcement support measures are needed, and the design philosophy regarding large parallel tunnels in weak rocks should be updated. This paper reports a recent case in which two large parallel diversion tunnels are excavated. The rock masses are thin- to ultra-thin-layered strata coated with phyllitic films, which significantly decrease the soundness and strength of the strata and weaken the rocks. The behaviors of the surrounding rock masses under original (and conventional) support measures are detailed in terms of rock mass deformation, anchor bolt stress, and the extent of the excavation disturbed zone (EDZ), as obtained from safety monitoring and field testing. In situ observed phenomena and their interpretation are also included. The sidewall deformations exhibit significant time-dependent characteristics, and large magnitudes are recorded. The stresses in the anchor bolts are small, but the extents of the EDZs are large. The stability condition under the original support measures is evaluated as poor. To enhance rock mass stability, attempts are made to reinforce support design and improve safety monitoring programs. The main feature of these attempts is the use of prestressed cables that run through the rock pillar between the parallel tunnels. The efficacy of reinforcement support measures is verified by further safety monitoring data and field test results. Numerical analysis is constantly performed during the construction process to provide a useful reference for decision making. The calculated deformations are in

  12. Case Study on Influence of Step Blast-Excavation on Support Systems of Existing Service Tunnel with Small Interval

    Directory of Open Access Journals (Sweden)

    Shaorui Sun


    Full Text Available During the construction of newly built tunnel (NBT adjacent to the existing service tunnel (EST, stability of the EST with small interval is affected by vibration waves which are caused by blasting load. The support structures of the EST will be cracked and damaged, while the unreasonable blast-excavation methods are adopted. Presently, the studies on behavior of support structure in the EST under blasting load are not totally clear, especially for the bolts system. Besides, the responses of support structure on blasting load are lacking comprehensive research. In this paper, New Zuofang tunnel is taken as a study case to study the influence of step blast-excavation in NBT on support structures of the EST through field experiment and numerical simulation. Some data, such as blasting vibration velocity (BVV and frequency of support structures, are obtained through field measurement. Based on these data, the formula of BVVs is obtained. Research on stability of tunnel support structures affected by step blast-excavation is conducted using numerical simulation method. The dynamic-plastic constitutive model is adopted in the software ABAQUS to assess safety of support structures. The range and degree of damage for the support structures are obtained. In addition, change laws of axial force and stress with time for the bolts are analyzed.

  13. A Mobility-Aware Adaptive Duty Cycling Mechanism for Tracking Objects during Tunnel Excavation. (United States)

    Kim, Taesik; Min, Hong; Jung, Jinman


    Tunnel construction workers face many dangers while working under dark conditions, with difficult access and egress, and many potential hazards. To enhance safety at tunnel construction sites, low latency tracking of mobile objects (e.g., heavy-duty equipment) and construction workers is critical for managing the dangerous construction environment. Wireless Sensor Networks (WSNs) are the basis for a widely used technology for monitoring the environment because of their energy-efficiency and scalability. However, their use involves an inherent point-to-point delay caused by duty cycling mechanisms that can result in a significant rise in the delivery latency for tracking mobile objects. To overcome this issue, we proposed a mobility-aware adaptive duty cycling mechanism for the WSNs based on object mobility. For the evaluation, we tested this mechanism for mobile object tracking at a tunnel excavation site. The evaluation results showed that the proposed mechanism could track mobile objects with low latency while they were moving, and could reduce energy consumption by increasing sleep time while the objects were immobile.

  14. A Mobility-Aware Adaptive Duty Cycling Mechanism for Tracking Objects during Tunnel Excavation

    Directory of Open Access Journals (Sweden)

    Taesik Kim


    Full Text Available Tunnel construction workers face many dangers while working under dark conditions, with difficult access and egress, and many potential hazards. To enhance safety at tunnel construction sites, low latency tracking of mobile objects (e.g., heavy-duty equipment and construction workers is critical for managing the dangerous construction environment. Wireless Sensor Networks (WSNs are the basis for a widely used technology for monitoring the environment because of their energy-efficiency and scalability. However, their use involves an inherent point-to-point delay caused by duty cycling mechanisms that can result in a significant rise in the delivery latency for tracking mobile objects. To overcome this issue, we proposed a mobility-aware adaptive duty cycling mechanism for the WSNs based on object mobility. For the evaluation, we tested this mechanism for mobile object tracking at a tunnel excavation site. The evaluation results showed that the proposed mechanism could track mobile objects with low latency while they were moving, and could reduce energy consumption by increasing sleep time while the objects were immobile.

  15. Investigating the Numerical Modelling of the Construction Excavation of an Actual Super Shallow Large-Span Tunnel (United States)

    Ma, Weijian; Xu, Qingli; Li, Jiang; Liu, Yang


    Owing to the complexity of structural characteristics, it is difficult to accurately model the super shallow large-span tunnel. In this study, aiming at an actual tunnel, we investigate the refined modelling of super shallow large-span tunnel. First, the three-dimension finite element model of this actual tunnel is established considering the disturbance of the surrounding rock, construction sequence and the change of stress state of structure during the construction process. Second, with the generated finite element model, the variation rules of the crown displacement and the initial lining stress are analysed numerically. Finally, the results of the numerical simulation are compared with the measured. The results show that the established model can simulate the construction excavation accurately.

  16. Examination of the Excavation Damaged Zone in the TASS tunnel, Aespoe HRL

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Mats (Swebrec, Luleaa Univ. of Technology, Luleaa (Sweden)); Markstroem, Ingemar; Pettersson, Anders; Straeng, Malin (Golder Associates, Uppsala (Sweden))


    The question of an existing continuous Excavation Damage Zone (EDZ) is very important for SKB. Is it possible to use drilling and blasting in the planned repository for spent nuclear fuel? Could fractures from blasting form a continuous EDZ? In order to increase the understanding of the EDZ and the possibility of an existing continuous EDZ along the deposition tunnel, SKB decided to examine the fracturing in a selected area of the TASS tunnel and to create a 3D model of the fractures in the investigated area. It was of special interest to study the transition zones between the blast rounds to examine if the EDZ from the bottom charges could form a continuous EDZ from one round to another. The TASS-tunnel is situated at the 450-m level in the Aespoe Hard Rock Laboratory. The tunnel, with a cross-section area of 20 m2, was planned to be 90 m long. In a subproject called Excavation the purpose was to test different plans for drilling, charging and initiation in order to give recommendations on how the final repository of spent fuel should be excavated. The test methodology used in this investigation comprised the following steps: selecting test area, drilling and wire sawing of blocks, surveying the blocks, removal and transportation of the blocks to the surface, cutting the blocks into slabs, fracture identification with penetrants, positioning and photographing the slabs, digitizing and 3D modelling of the fractures. The test area for EDZ consisted of an 8 m long and 1.5 m high section in excavation sequence no 4. The selected section covered the end of round 9, the entire round 10 and the start of round 11. In the contour and the helpers small diameter charges for smooth blasting were used (decoupled charges). These charges also have a relatively low detonation velocity (VOD) and this, together with the decoupling, gives short fracture lengths i.e. a small EDZ. The contour holes and the helpers were initiated with electronic detonators to achieve a simultaneous

  17. Stability assessment for underground excavations and key construction techniques

    CERN Document Server

    Zhu, Hanhua; Zhao, Yu; Niu, Fusheng


    This book examines how the state of underground structures can be determined with the assistance of force, deformation and energy. It then analyzes mechanized shield methods, the New Austrian tunneling method (NATM) and conventional methods from this new perspective. The book gathers a wealth of cases reflecting the experiences of practitioners and administrators alike. Based on statistical and engineering studies of these cases, as well as lab and field experiments, it develops a stability assessment approach incorporating a stable equilibrium, which enables engineers to keep the structure and surrounding rocks safe as long as the stable equilibrium and deformation compliance are maintained. The book illustrates the implementation of the method in various tunneling contexts, including soil-rock mixed strata, tunneling beneath operating roads, underwater tunnels, and tunnel pit excavation. It offers a valuable guide for researchers, designers and engineers, especially those who are seeking to understand the u...

  18. Reliability and Assessment Techniques on Ground Excavation

    Directory of Open Access Journals (Sweden)

    Sanga Tangchawal


    Full Text Available Planning and assessment on the excavation of the brittle materials (soil or rock can be done by using the machinery and/or explosives. The reliability assessment has been proposed to predict the failure of ground during excavation process. The stability planning on cutting soil (rock face by machinery can be compared between the deterministic and the statistical method. The risk of using explosives for rock excavation has to concern on the damage and environmental impacts after blasting events.

  19. Behavioral and mechanical determinants of collective subsurface nest excavation. (United States)

    Monaenkova, Daria; Gravish, Nick; Rodriguez, Greggory; Kutner, Rachel; Goodisman, Michael A D; Goldman, Daniel I


    Collective construction of topologically complex structures is one of the triumphs of social behavior. For example, many ant species construct underground nests composed of networks of tunnels and chambers. Excavation by these 'superorganisms' depends on the biomechanics of substrate manipulation, the interaction of individuals, and media stability and cohesiveness. To discover principles of robust social excavation, we used X-ray computed tomography to monitor the growth in three dimensions of nests built by groups of fire ants (Solenopsis invicta) in laboratory substrates composed of silica particles, manipulating two substrate properties: particle size and gravimetric moisture content. Ants were capable of nest construction in all substrates tested other than completely dry or fully saturated; for a given particle size, nest volume was relatively insensitive to moisture content. Tunnels were deepest at intermediate moisture content and the maximum tunnel depth correlated with measured yield force on small rod-shaped intruders (a proxy for cohesive strength). This implies that increased cohesive strength allowed creation of tunnels that were resistant to perturbation but did not decrease individual excavation ability. Ants used two distinct behaviors to create pellets composed of wetted particles, depending on substrate composition. However, despite the ability to create larger stable pellets in more cohesive substrates, pellet sizes were similar across all conditions. We posit that this pellet size balances the individual's load-carrying ability with the need to carry this pellet through confined crowded tunnels. We conclude that effective excavation of similarly shaped nests can occur in a diversity of substrates through sophisticated digging behaviors by individuals which accommodate both differing substrate properties and the need to work within the collective. © 2015. Published by The Company of Biologists Ltd.


    Directory of Open Access Journals (Sweden)

    Huaming An


    Full Text Available A hybrid finite-discrete element method (FEM/DEM is introduced to model the excavation damage zone induced by blast in a deep tunnel. The key components of the hybrid finite-discrete element method, i.e. transition from continuum to discontinuum through fracture and fragmentation, and detonation-induced gas expansion and flow through fracturing rock, are introduced in detail. The stress and crack initiation and propagation of an uniaxial compression test is then modelled by the proposed method and compared with those well documented in literature to calibrate the hybrid FEM/DEM. The modelled stress-loading displacement curve presents a typical failure process of brittle materials. The calibrated method is then used to model the stress and crack initiation and propagation induced by blast for the last step of excavation in a deep tunnel. A separation contour, which connects the borehole through the radial cracks from each borehole, is observed during the excavation process. The newly formed tunnel wall is produced and the main components of excavation damage zone (EDZ are obtained. Therefore, the proposed treatment has the capabilities of modelling blast-induced EDZ and rock failure process. It is concluded that the hybrid FEM/DEM is a valuable numerical tool for studying excavation damage zone in terms of crack initiation and propagation and stress distribution.

  1. The Big Dig : the excavation of the LEP tunnel was the most formidable civil-engineering venture in the history of CERN and Europe's largest civil-engineering project prior to the Channel Tunnel.

    CERN Multimedia


    Siting a 27-km long underground ring in the corridor between the Jura mountains and Lake Geneva was no easy matter. After several proposals, the decision was made to install the ring along the foot of the Jura range. However, owing to geological features the tunnel had to be built on a gradient of 1.4 %, sloping towards the Lake.

  2. Slope excavation quality assessment and excavated volume calculation in hydraulic projects based on laser scanning technology

    Directory of Open Access Journals (Sweden)

    Chao Hu


    Full Text Available Slope excavation is one of the most crucial steps in the construction of a hydraulic project. Excavation project quality assessment and excavated volume calculation are critical in construction management. The positioning of excavation projects using traditional instruments is inefficient and may cause error. To improve the efficiency and precision of calculation and assessment, three-dimensional laser scanning technology was used for slope excavation quality assessment. An efficient data acquisition, processing, and management workflow was presented in this study. Based on the quality control indices, including the average gradient, slope toe elevation, and overbreak and underbreak, cross-sectional quality assessment and holistic quality assessment methods were proposed to assess the slope excavation quality with laser-scanned data. An algorithm was also presented to calculate the excavated volume with laser-scanned data. A field application and a laboratory experiment were carried out to verify the feasibility of these methods for excavation quality assessment and excavated volume calculation. The results show that the quality assessment indices can be obtained rapidly and accurately with design parameters and scanned data, and the results of holistic quality assessment are consistent with those of cross-sectional quality assessment. In addition, the time consumption in excavation project quality assessment with the laser scanning technology can be reduced by 70%−90%, as compared with the traditional method. The excavated volume calculated with the scanned data only slightly differs from measured data, demonstrating the applicability of the excavated volume calculation method presented in this study.

  3. Slope excavation quality assessment and excavated volume calculation in hydraulic projects based on laser scanning technology

    Directory of Open Access Journals (Sweden)

    Chao Hu


    Full Text Available Slope excavation is one of the most crucial steps in the construction of a hydraulic project. Excavation project quality assessment and excavated volume calculation are critical in construction management. The positioning of excavation projects using traditional instruments is inefficient and may cause error. To improve the efficiency and precision of calculation and assessment, three-dimensional laser scanning technology was used for slope excavation quality assessment. An efficient data acquisition, processing, and management workflow was presented in this study. Based on the quality control indices, including the average gradient, slope toe elevation, and overbreak and underbreak, cross-sectional quality assessment and holistic quality assessment methods were proposed to assess the slope excavation quality with laser-scanned data. An algorithm was also presented to calculate the excavated volume with laser-scanned data. A field application and a laboratory experiment were carried out to verify the feasibility of these methods for excavation quality assessment and excavated volume calculation. The results show that the quality assessment indices can be obtained rapidly and accurately with design parameters and scanned data, and the results of holistic quality assessment are consistent with those of cross-sectional quality assessment. In addition, the time consumption in excavation quality assessment with the laser scanning technology can be reduced by 70%–90%, as compared with the traditional method. The excavated volume calculated with the scanned data only slightly differs from measured data, demonstrating the applicability of the excavated volume calculation method presented in this study.

  4. Strata control in tunnels and an evaluation of support units and systems currently used with a view to improving the effectiveness of support stability and safety of tunnels.

    CSIR Research Space (South Africa)

    Haile, AT


    Full Text Available This project report addresses the issue of strata control in tunnel excavations with the aim of improving the stability of the excavation through improved design methodologies and support systems....

  5. An in vitro comparison of fluorescence-aided caries excavation and conventional excavation by microhardness testing. (United States)

    Lai, Guangyun; Zhu, Laikuan; Xu, Xiaohui; Kunzelmann, Karl-Heinz


    The aim of this in vitro study was to compare fluorescence-aided caries excavation with conventional excavation based on the Martens and Vickers hardness of dentin at the cavity floor after caries removal. In total, 20 extracted human teeth with dentin caries were bisected through the lesion center into two halves, which were assigned to either the fluorescence-aided caries excavation group or the conventional excavation group. After the treatment, embedding, mounting, and polishing, a line of indentations from the dental pulp across the sound dentin to the cavity floor was made on each sample. The data were compared with Student's t and Mann-Whitney U tests. The calculated Vickers hardness of the sound dentin was 57 ± 10 kg/mm(2) in the fluorescence-aided caries excavation group and 59 ± 8 kg/mm(2) in the conventional excavation group, which is consistent with the previous studies. The absolute and relative Martens hardness measurements of the cavity floor were 224 ± 93 N/mm(2) and 46 ± 17%, respectively, in the fluorescence-aided caries excavation group and 412 ± 75 N/mm(2) and 81 ± 14%, respectively, in the conventional excavation group. Based on either the Martens or Vickers hardness, both the absolute and relative microhardness measurements of the cavity floor after fluorescence-aided caries excavation were significantly lower than the values obtained by conventional excavation. Fluorescence-aided caries excavation showed the tissue-preserving property and was more conservative than the conventional excavation in this in vitro study.

  6. Pajarito Plateau archaeological surveys and excavations. II

    Energy Technology Data Exchange (ETDEWEB)

    Steen, C R


    Los Alamos National Laboratory continues its archaeological program of data gathering and salvage excavations. Sites recently added to the archaeological survey are described, as well as the results of five excavations. Among the more interesting and important discoveries are (1) the apparently well-established local use of anhydrous lime, and (2) a late pre-Columbian use of earlier house sites and middens for garden plots. Evidence indicated that the local puebloan population was the result of an expansion of upper Rio Grande peoples, not an influx of migrants.

  7. A Mobility-Aware Adaptive Duty Cycling Mechanism for Tracking Objects during Tunnel Excavation


    Taesik Kim; Hong Min; Jinman Jung


    Tunnel construction workers face many dangers while working under dark conditions, with difficult access and egress, and many potential hazards. To enhance safety at tunnel construction sites, low latency tracking of mobile objects (e.g., heavy-duty equipment) and construction workers is critical for managing the dangerous construction environment. Wireless Sensor Networks (WSNs) are the basis for a widely used technology for monitoring the environment because of their energy-efficiency and s...

  8. Principles of Mechanical Excavation

    Energy Technology Data Exchange (ETDEWEB)

    Lislerud, A. [Tamrock Corp., Tampere (Finland)


    Mechanical excavation of rock today includes several methods such as tunnel boring, raiseboring, roadheading and various continuous mining systems. Of these raiseboring is one potential technique for excavating shafts in the repository for spent nuclear fuel and dry blind boring is promising technique for excavation of deposition holes, as demonstrated in the Research Tunnel at Olkiluoto. In addition, there is potential for use of other mechanical excavation techniques in different parts of the repository. One of the main objectives of this study was to analyze the factors which affect the feasibility of mechanical rock excavation in hard rock conditions and to enhance the understanding of factors which affect rock cutting so as to provide an improved basis for excavator performance prediction modeling. The study included the following four main topics: (a) phenomenological model based on similarity analysis for roller disk cutting, (b) rock mass properties which affect rock cuttability and tool life, (c) principles for linear and field cutting tests and performance prediction modeling and (d) cutter head lacing design procedures and principles. As a conclusion of this study, a test rig was constructed, field tests were planned and started up. The results of the study can be used to improve the performance prediction models used to assess the feasibility of different mechanical excavation techniques at various repository investigation sites. (orig.). 21 refs.



    Pavle Jureta; Zvonimir Deković


    The modes of pipe roof technology implementation in order to stabilize the excavations on the "Javorova Kosa" and "Pod Vugles" Tunnels are described in the paper. Both tunnels are specific regarding their geological structure and geo-technical characteristics of the rock mass in which the excavations were performed as well as regarding the mutual distance of 50 m measured alongside the highway axis. The multiphase New Austrian Tunneling Method (NATM) was used for the excavations in weak rock/...

  10. Nest enlargement in leaf-cutting ants: relocated brood and fungus trigger the excavation of new chambers.

    Directory of Open Access Journals (Sweden)

    Daniela Römer

    Full Text Available During colony growth, leaf-cutting ants enlarge their nests by excavating tunnels and chambers housing their fungus gardens and brood. Workers are expected to excavate new nest chambers at locations across the soil profile that offer suitable environmental conditions for brood and fungus rearing. It is an open question whether new chambers are excavated in advance, or will emerge around brood or fungus initially relocated to a suitable site in a previously-excavated tunnel. In the laboratory, we investigated the mechanisms underlying the excavation of new nest chambers in the leaf-cutting ant Acromyrmex lundi. Specifically, we asked whether workers relocate brood and fungus to suitable nest locations, and to what extent the relocated items trigger the excavation of a nest chamber and influence its shape. When brood and fungus were exposed to unfavorable environmental conditions, either low temperatures or low humidity, both were relocated, but ants clearly preferred to relocate the brood first. Workers relocated fungus to places containing brood, demonstrating that subsequent fungus relocation spatially follows the brood deposition. In addition, more ants aggregated at sites containing brood. When presented with a choice between two otherwise identical digging sites, but one containing brood, ants' excavation activity was higher at this site, and the shape of the excavated cavity was more rounded and chamber-like. The presence of fungus also led to the excavation of rounder shapes, with higher excavation activity at the site that also contained brood. We argue that during colony growth, workers preferentially relocate brood to suitable locations along a tunnel, and that relocated brood spatially guides fungus relocation and leads to increased digging activity around them. We suggest that nest chambers are not excavated in advance, but emerge through a self-organized process resulting from the aggregation of workers and their density

  11. Nest enlargement in leaf-cutting ants: relocated brood and fungus trigger the excavation of new chambers. (United States)

    Römer, Daniela; Roces, Flavio


    During colony growth, leaf-cutting ants enlarge their nests by excavating tunnels and chambers housing their fungus gardens and brood. Workers are expected to excavate new nest chambers at locations across the soil profile that offer suitable environmental conditions for brood and fungus rearing. It is an open question whether new chambers are excavated in advance, or will emerge around brood or fungus initially relocated to a suitable site in a previously-excavated tunnel. In the laboratory, we investigated the mechanisms underlying the excavation of new nest chambers in the leaf-cutting ant Acromyrmex lundi. Specifically, we asked whether workers relocate brood and fungus to suitable nest locations, and to what extent the relocated items trigger the excavation of a nest chamber and influence its shape. When brood and fungus were exposed to unfavorable environmental conditions, either low temperatures or low humidity, both were relocated, but ants clearly preferred to relocate the brood first. Workers relocated fungus to places containing brood, demonstrating that subsequent fungus relocation spatially follows the brood deposition. In addition, more ants aggregated at sites containing brood. When presented with a choice between two otherwise identical digging sites, but one containing brood, ants' excavation activity was higher at this site, and the shape of the excavated cavity was more rounded and chamber-like. The presence of fungus also led to the excavation of rounder shapes, with higher excavation activity at the site that also contained brood. We argue that during colony growth, workers preferentially relocate brood to suitable locations along a tunnel, and that relocated brood spatially guides fungus relocation and leads to increased digging activity around them. We suggest that nest chambers are not excavated in advance, but emerge through a self-organized process resulting from the aggregation of workers and their density-dependent digging behavior

  12. MicroCT-based comparison between fluorescence-aided caries excavation and conventional excavation. (United States)

    Lai, Guangyun; Kaisarly, Dalia; Xu, Xiaohui; Kunzelmann, Karl-Heinz


    To evaluate and compare the use of micro-computed tomography (microCT) to investigate the mineral concentration of the treated dentin surface after caries removal with fluorescence-aided caries excavation (FACE) and conventional excavation. 20 extracted human teeth with dentin caries were bisected through the lesion center into two halves which were distributed to a FACE and a conventional excavation group. Tungsten-carbide round burs were used for both groups. Each specimen was investigated with microCT after excavation. The obtained images of all the specimens were evaluated using Image J. Based on the grey values, the linear attenuation coefficients were calculated. Four resin-embedded solid hydroxyapatite phantoms with the gradually increased mineral concentration were used to obtain a calibration curve and equation. Finally, the mineral concentration values of the superficial dentin of each specimen after removal and sound dentin were calculated. The data were compared with the Student's t-test. The statistical results showed that the linear attenuation coefficient (LAC) of the treated surface was significantly lower (P excavation group was 2.98 +/- 0.19 cm(-1). The LAC of sound dentin was 3.89 +/- 0.10 cm(-1). By using the calibration equation, the calculated mineral concentration of the superficial dentin after caries removal were 0.68 +/- 0.14 g/cm3 in the FACE group and 1.05 +/- 0.08 g/cm3 in the conventional excavation group. The mineral concentration of sound dentin was 1.44 +/- 0.04 g/cm3. The mineral concentration of the superficial dentin after caries removal in the FACE group was about 47% of that of sound dentin, while the value in the conventional excavation group was approximately 73% of that of sound dentin. Under the conditions of this in vitro study, the results of the microCT evaluation may imply that FACE was more conservative than conventional excavation.

  13. Excavating and loading equipment for peat mining (United States)

    Mikhailov, A. V.; Zhigulskaya, A. I.; Yakonovskaya, T. B.


    Recently, the issues of sustainable development of Russian regions, related to ensuring energy security, are more urgent than ever. To achieve sustainable development, an integrated approach to the use of local natural resources is needed. Practically in all north regions of the Russian Federation, peat as a local natural resource is widespread, which has a practical application in the area of housing services. The paper presents the evaluation of technologies for open-pit peat mining, as well as analysis of technological equipment for peat production. Special attention is paid to a question of peat materials excavating and loading. The problem of equipment selection in a peat surface mine is complex. Many features, restrictions and criteria need to be considered. Use of low and ultra-low ground pressure excavators and low ground pressure front-end loaders with full-range tires to provide the necessary floatation in the peat bog environment is offered.

  14. Fluorescence-aided caries excavation (FACE), caries detector, and conventional caries excavation in primary teeth. (United States)

    Lennon, Aine M; Attin, Thomas; Martens, Sabine; Buchalla, Wolfgang


    The purpose of this paper was to compare the ability of fluorescence-aided caries excavation (FACE) to remove infected dentin in primary teeth with that of conventional methods. Sixty-six extracted carious primary teeth were divided according to lesion size into 3 groups of 22 teeth. Caries excavation was carried out with a slow-speed handpiece and round burs for all groups. In the first group, caries was excavated conventionally using visual tactile criteria. In the second group, a caries detector dye was used to detect carious dentin. In the FACE group, cavities were excited with violet light (370-420 nm) and observed through a 530 nm highpass filter. Orange-red fluorescing areas were removed. Undecalcified thin slices were prepared, stained with Giemsa, and examined for presence of infected dentin using light microscopy. Four samples were lost during processing. Histology showed infected dentin in significantly less FACE samples (3 of 22) compared to conventional excavation (9 of 20; P=.03), but not significantly less compared to caries detector (5 of 20; P=.35). Within the limitations of this in vitro study, it can be concluded that fluorescence-aided caries excavation is more effective than conventional excavation in removal of infected primary dentin.

  15. Discrete Element Modeling for Mobility and Excavation (United States)

    Knuth, M. A.; Hopkins, M. A.


    The planning and completion of mobility and excavation efforts on the moon requires a thorough understanding of the planetary regolith. In this work, a discrete element method (DEM) model is created to replicate those activities in the laboratory and for planning mission activities in the future. The crux of this work is developing a particle bed that best replicates the regolith tool/wheel interaction seen in the laboratory. To do this, a DEM geotechnical triaxial strength cell was created allowing for comparison of laboratory JSC-1a triaxial tests to DEM simulated soils. This model relies on a triangular lattice membrane covered triaxial cell for determining the macroscopic properties of the modeled granular material as well as a fast and efficient contact detection algorithm for a variety of grain shapes. Multiple grain shapes with increasing complexity (ellipsoid, poly-ellipsoid and polyhedra) have been developed and tested. This comparison gives us a basis to begin scaling DEM grain size and shape to practical values for mobility and excavation modeling. Next steps include development of a DEM scoop for percussive excavation testing as well as continued analysis of rover wheel interactions using a wide assortment of grain shape and size distributions.

  16. National Advanced Drilling and Excavation Technologies Program

    Energy Technology Data Exchange (ETDEWEB)



    The second meeting of Federal agency representatives interested in the National Advanced Drilling and Excavation Technologies (NADET) Program took place on June 15, 1993. The Geothermal Division of the U.S. Department of Energy (DOE) hosted the meeting at the Washington, D.C., offices of DOE. Representatives from the National Science Foundation, U.S. Geological Survey, U.S. Bureau of Mines, National Institute of Standards and Technology, National Aeronautics and Space Administration, Environmental Protection Agency, and various offices within the Department of Energy attended. For a complete list of attendees see Attachment A. The purpose of the meeting was: (1) to cover the status of efforts to gain formal approval for NADET, (2) to brief participants on events since the last meeting, especially two recent workshops that explored research needs in drilling and excavation, (3) to review some recent technological advances, and (4) to solicit statements of the importance of improving drilling and excavation technologies to the missions of the various agencies. The meeting agenda is included as Attachment B.

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

    National Research Council Canada - National Science Library

    Christoph Butscher; Herbert H. Einstein; Peter Huggenberger


    .... 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...

  18. Focal choroidal excavation: Clinical findings and complications. (United States)

    Castro Navarro, V; Montero Hernández, J; Navarro Palop, C; Palomares Fort, P; Cervera Taulet, E


    To describe the clinical findings and its complications in 2 patients with focal choroidal excavation (FCE). A retrospective case-series including 4 eyes of 2 patients with FCE that underwent a comprehensive ophthalmological examination including slit-lamp examination, colour fundus photography, spectral-domain optical coherence tomography (SD-OCT), fluorescein angiography (FA), and indocyanine green angiography. In the 2 patients, both the anterior and posterior segment evaluations were mostly normal despite the of presence yellowish spots in the macular area of the right eye of patient 1, and of a small yellowish elevated lesion with serous macular detachment in the macular area of the left eye in patient 2. At diagnosis, SD-OCT revealed a conforming FCE in patient 1, and in patient 2, an FCE with perilesional subretinal fluid and a neuroepithelium detachment, suspicious of FCE complicated with central serous retinopathy (CSCR). At one year of follow-up, patient 1 developed choroidal neovascularisation (CNV) over the focal choroidal excavation. FA and indocyanine green angiography examinations revealed areas with hypofluorescence in earlier frames, and a diffuse leakage in late frames. After ranibizumab injections, the SD-OCT of patient 1 revealed no active exudation, while patient 2 showed partial resolution of subretinal fluid. FCE is a newly described entity of unclear aetiology. It is characterised by a choroidal excavation in eyes, with absence of posterior staphyloma, scleral ectasia, trauma, or retinal disease. Although most lesions remain stable, there could be an association with CRSC or CNV. Copyright © 2015 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  19. Excavation of the SPS tunnel (view of a section prior to lining by a concrete shell)

    CERN Multimedia


    The SPS ring (6911 m in circumference) is housed at a depth of 40 m (average) under the surface. The tunnel with an overall cross-sectional diameter of 4.8 m was drilled by big tunnelling machines (see 7406022X, 7406027X) into the molasse rock present in the Geneva basin. After the passage of the tunnelling machine the tunnel walls were lined with a concrete layer of about 30cm thickness.

  20. Theory and technology of rock excavation for civil engineering

    CERN Document Server

    Zou, Dingxiang


    This book summarizes the technical advances in recent decades and the various theories on rock excavation raised by scholars from different countries, including China and Russia. It not only focuses on rock blasting but also illustrates a number of non-blasting methods, such as mechanical excavation in detail. The book consists of 3 parts: Basic Knowledge, Surface Excavation and Underground Excavation. It presents a variety of technical methods and data from diverse sources in the book, making it a valuable theoretical and practical reference resource for engineers, researchers and postgraduates alike.

  1. Characterisation of Excavation-Induced Damage Around a Short Test Tunnel in the Opalinus Clay (United States)

    Yong, Salina; Loew, Simon; Schuster, Kristof; Nussbaum, Christophe; Fidelibus, Corrado


    In Switzerland, the Opalinus Clay is under consideration as a potential host rock for deep geological storage of nuclear waste. The Swiss concept involves high-level waste containers emplaced in small-diameter drifts of roughly 3 m. At the Mont Terri Underground Rock Laboratory, a short mine-by experiment (EZ-B) was executed in 2005 with the objective of characterising the excavation-induced damage through an interpretation of integrated field data. The damage zone was found to consist of two parts. Fracture mapping from drillcores and televiewer images revealed a thin inner zone of macroscopic fracturing (20 cm) and devoid of borehole instabilities as well as coinciding with the lowest P-wave characteristics (normalised amplitudes and velocities). The outer zone (50-80 cm) was defined by increasing P-wave characteristics and evidence of borehole instabilities. Supplementing the data interpretation, a simplified numerical elastic stress analysis indicated that the rock mass in the sidewalls and upper western haunch are the most susceptible to spalling. In these regions, stress levels only just reach a spalling limit around 0.05 in the inner fractured zone, suggesting that the zone of macro-fracturing around the niche is not significant. It is postulated that the physical manifestation of the relatively weak bedding plane strength is dominated by bedding-perpendicular displacement as opposed to bedding-parallel shear.

  2. Woodpecker Excavation and Use of Cavities in Polystyrene Snags (United States)

    Richard N. Conner; Daniel Saenz


    We examined woodpecker excavation and use of artificial polystyrene snags in four forest types in eastern Texas for five years. Twenty-three of 47 artificial snags were used by Downy Woodpeckers (Picoides pubescens) for cavity excavation and subsequent nocturnal roosting; they did not use the artificial snags for nesting. Although six ather species of woodpeckers...

  3. Experience in design and construction of the Log tunnel

    Directory of Open Access Journals (Sweden)

    Jovičić Vojkan


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

  4. Experience in design and construction of the Log tunnel (United States)

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


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


    Ghadiali, Quraish; Dansingani, Kunal K; Freund, K Bailey


    To report a case of focal choroidal excavation and choroidal neovascularization in the setting of pachychoroid disease. Multimodal imaging, including fundus photography, fundus autofluorescence, enhanced depth imaging optical coherence tomography, indocyanine green angiography, and en face structural and angiographic optical coherence tomography. The authors describe a 39-year-old female with moderately high myopia presenting with focal choroidal excavation and associated choroidal neovascularization. Multimodal imaging demonstrated pachychoroid features with dilated choroidal vessels surrounding the lesion. Optical coherence tomography angiography showed Type 2 neovascularization. Some cases of focal choroidal excavation and associated neovascularization may be related to structural abnormalities of the associated choroidal vasculature.

  6. Presence of a radioactive gas in archaeological excavations, determination and mitigation. (United States)

    Balcázar, M; Gómez, S; Peña, P; Zavala Arredondo, J; Gazzola, J; Villamares, A


    During recent archaeological discovery and excavation of a tunnel build approximately 2000 years ago by the Teotihuacans under the feathered serpent temple, in Mexico, abnormal radon concentrations up to 700 Bq m(-3) were measured at several excavation stages. The tunnel is at 15m below the earth surface with a vertical rectangular entrance of 4×4 m(2), a semi cylindrical shape of 3m in diameter, with a probable length of 100 m. This study supports the assumption that at the opening of the tunnel radon concentration was around 5500 Bq m(-3); however, although natural convection in the tunnel atmosphere naturally pups radon out, it build up to a maximum concentration of 2000 Bq m(-3). This paper presents the identification of the radon problem in this archaeological site, dose determination, and the mitigation actions that reduced the radon concentration down to 40 Bq m(-3) that ensure a negligible radon risk for archaeologist. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Quantity of remaining bacteria and cavity size after excavation with FACE, caries detector dye and conventional excavation in vitro. (United States)

    Lennon, Aine M; Attin, Thomas; Buchalla, Wolfgang


    In this in vitro study, quantitative confocal microscopy was used to show differences in the quantity of bacteria remaining in dentin after excavation with different methods. A further parameter was the cavity volume after excavation relative to the original lesion size. Teeth with dentin caries were divided into three groups of 20 each. The caries was removed by a single operator using a slow handpiece and a round bur. In the first group, Fluorescence Aided Caries Excavation (FACE) was carried out: violet light was used to illuminate the operating field and the operator observed the cavity through a high-pass filter and removed the orange-red fluorescing areas. The second group was excavated using Caries Detector, while the third group used conventional excavation. After excavation, cavity volume was measured; samples were stained for bacteria with ethidium bromide, and they were examined using confocal microscopy under standardized conditions. The bound stain was quantified in terms of fluorescence intensity on the confocal images. Total pixel intensity was significantly lower in the FACE Group than in the Caries Detector group (p = 0.046) and in the conventional excavation group (p = 0.021). Differences in cavity volume relative to original lesion size were not statistically significant (p = 0.86, 0.35 and 0.51). Within the limitations of this in vitro study, it can be concluded that FACE is more effective in removing infected dentin without significantly increasing cavity size when compared to conventional excavation and excavation with the aid of caries detector dye.

  8. Analysis of labour accidents in tunnel construction and introduction of prevention measures


    Kikkawa, Naotaka; Itoh, Kazuya; Hori, Tomohito; TOYOSAWA, Yasuo; Orense, Rolando P.


    At present, almost all mountain tunnels in Japan are excavated and constructed utilizing the New Austrian Tunneling Method (NATM), which was advocated by Prof. Rabcewicz of Austria in 1964. In Japan, this method has been applied to tunnel construction since around 1978, after which there has been a subsequent decrease in the number of casualties during tunnel construction. However, there is still a relatively high incidence of labour accidents during tunnel construction when compared to incid...


    Directory of Open Access Journals (Sweden)

    Zvonimir Deković


    Full Text Available The paper describes organisational-technological characteristics of blasting works during the excavation of the Grič Tunnel. The significance of blasting works during the excavation of the tunnel is shown through adjustment of blasting parameters taking into consideration the dynamics of the works, cost-effectiveness and influence of geological circumstances. Successfulness of blasting directly influences the subsequent tunnel excavation cycle both in terms of duration as well as eventually in terms of influence on the entire tunnel investment. Comparison of changes of basic blasting parameters during tunnel excavation ensured optimal excavation progress with minimal price per meter of tunnel progress.

  10. Research on Trajectory Planning and Autodig of Hydraulic Excavator

    Directory of Open Access Journals (Sweden)

    Bin Zhang


    Full Text Available As the advances in computer control technology keep emerging, robotic hydraulic excavator becomes imperative. It can improve excavation accuracy and greatly reduce the operator’s labor intensity. The 12-ton backhoe bucket excavator has been utilized in this research work where this type of excavator is commonly used in engineering work. The kinematics model of operation device (boom, arm, bucket, and swing in excavator is established in both Denavit-Hartenberg coordinates for easy programming and geometric space for avoiding blind spot. The control approach is based on trajectory tracing method with displacements and velocities feedbacks. The trajectory planning and autodig program is written by Visual C++. By setting the bucket teeth’s trajectory, the program can automatically plan the velocity and acceleration of each hydraulic cylinder and motor. The results are displayed through a 3D entity simulation environment which can present real-time movements of excavator kinematics. Object-Oriented Graphics Rendering Engine and skeletal animation are used to give accurate parametric control and feedback. The simulation result shows that a stable linear autodig can be achieved. The errors between trajectory planning command and simulation model are analyzed.

  11. Tunnels: different construction methods and its use for pipelines installation

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, Tales; Soares, Ana Cecilia; Assis, Slow de; Bolsonaro, Ralfo; Sanandres, Simon [Petroleo do Brasil S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)


    In a continental dimensions country like Brazil, the pipeline modal faces the challenge of opening ROW's in the most different kind of soils with the most different geomorphology. To safely fulfill the pipeline construction demand, the ROW opening uses all techniques in earthworks and route definition and, where is necessary, no digging techniques like horizontal directional drilling, micro tunneling and also full size tunnels design for pipelines installation in high topography terrains to avoid geotechnical risks. PETROBRAS has already used the tunnel technique to cross higher terrains with great construction difficult, and mainly to make it pipeline maintenance and operation easier. For the GASBOL Project, in Aparados da Serra region and in GASYRG, in Bolivia, two tunnels were opened with approximately 700 meters and 2,000 meters each one. The GASBOL Project had the particularity of being a gallery with only one excavation face, finishing under the hill and from this point was drilled a vertical shaft was drilled until the top to install the pipeline section, while in GASYRG Project the tunnel had two excavation faces. Currently, two projects are under development with tunnels, one of then is the Caraguatatuba-Taubate gas pipeline (GASTAU), with a 5 km tunnel, with the same concepts of the GASBOL tunnel, with a gallery to be opened with the use of a TBM (Tunneling Boring Machine), and a shaft to the surface, and the gas pipeline Cabiunas-Reduc III (GASDUC III) project is under construction with a 3.7 km tunnel, like the GASYRG tunnel with two faces. This paper presents the main excavation tunneling methods, conventional and mechanized, presenting the most relevant characteristics from both and, in particular, the use of tunnels for pipelines installation. (author)

  12. Cratos: A Simple Low Power Excavation and Hauling System for Lunar Oxygen Production and General Excavation Tasks (United States)

    Caruso, John J.; Greer, Lawrence C.; John, Wentworth T.; Spina, Dan C.; Krasowski, Mike J.; Abel, Phillip B.; Prokop, Norman F.; Flatico, Joseph M.; Sacksteder, Kurt R.


    The development of a robust excavating and hauling system for lunar and planetary excavation is critical to the NASA mission to the Moon and Mars. Cratos was developed as a low center of gravity, small (.75m x .75m x 0.3m), low power tracked test vehicle. The vehicle was modified to excavate and haul because it demonstrated good performance capabilities in a laboratory and field testing. Tested on loose sand in the SLOPE facility, the vehicle was able to pick up, carry, and dump sand, allowing it to accomplish the standard requirements delivery of material to a lunar oxygen production site. Cratos can pick up and deliver raw material to a production plant, as well as deliver spent tailings to a disposal site. The vehicle can complete many other In-Situ Resource Utilization (ISRU) excavation chores and in conjunction with another vehicle or with additional attachments may be able to accomplish all needed ISRU tasks.


    Directory of Open Access Journals (Sweden)

    Pavle Jureta


    Full Text Available The modes of pipe roof technology implementation in order to stabilize the excavations on the "Javorova Kosa" and "Pod Vugles" Tunnels are described in the paper. Both tunnels are specific regarding their geological structure and geo-technical characteristics of the rock mass in which the excavations were performed as well as regarding the mutual distance of 50 m measured alongside the highway axis. The multiphase New Austrian Tunneling Method (NATM was used for the excavations in weak rock/soil (the paper is published in Croatian.

  14. Aespoe Hard Rock Laboratory. Studies of factors that affect and controls the Excavation Damaged/Disturbed Zone

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Martin; Baeckstroem, Ann; Quanhong Feng (AaF - Berg och Maetteknik, Stockholm (Sweden)); Berglund, Johan (Vattenfall Power Consultant, Stockholm (Sweden)); Johansson, Malin; Mas Ivars, Diego (Itasca Geomekanik AB, Solna (Sweden)); Olsson, Mats (SweBefo, Stockholm (Sweden))


    A tunnel was developed at the Aespoe Hard Rock Laboratory (HRL) in 2003 purposely for a large in-situ rock mechanics experiment, the Aespoe Pillar Stability Experiment (APSE). The tunnel had a large height/width ratio with a circular floor, primarily to control the stress situation around the tunnel and concentrate the stresses under the floor. An extensive set of data for understanding the Excavation Damaged Zone (EDZ) was collected within section 47 of the tunnel. It consist of the blast design, blast sequences, convergence measurements during excavation, geological mapping of tunnel and cores, 3D-laser scanning of the tunnel geometry etc. Furthermore, in 2006, ultrasonic measurements along eight boreholes were carried out in order to estimate the extent of the EDZ in the tunnel. The collection of all these different information provides an opportunity to evaluate the mechanical damages caused by the excavation work. The overall aim with this project is to give feed-back to future planning of tunnelling on issues of importance for requirements with respect to minimising the EDZ in crystalline rock from the drill and blast method. A combination of the mapped geological features (tunnel and cores) and the geometry of the blasted tunnel obtained from the 3D-laser scanning were used to build a 3D model of the geology with emphasis on the geometry of the natural fractures. The rock mechanic response to the tunnelling was evaluated in a numerical model including the as-built geometry in combination with the 3D model of the geology. The modelling of the rock mechanical processes of importance for the EDZ could be calibrated against actual measurements. From observed changes in the ultrasonic wave velocity along the boreholes it was found that the locations of the velocity changes corresponded well with the location of the mapped fractures in the drill cores. This indicates that EDZ can be detected using the ultrasonic method with high accuracy. Furthermore, the

  15. Excavation damage and disturbance in crystalline rock - results from experiments and analyses

    Energy Technology Data Exchange (ETDEWEB)

    Baeckblom, Goeran (Conrox AB, Stockholm (Sweden))


    calculations using the PHREEQC code showed that fracture precipitation is unlikely to clog the water-conducting fractures within a 10-year period, even when considering construction material such as cement and nitrogen compounds. For most of the modelling cases, the estimated decrease in hydraulic conductivity over a period of ten years is less than 2% due to mineral precipitation. It was further concluded that it is more likely for fractures to clog (self-heal) than become open as a result of fracture mineral dissolution. With respect to the microbial evolution it was concluded that the potential for microbial iron hydroxide production will be large in all groundwater with ferrous iron. The potential for microbial calcite formation production will be large in all groundwater with high concentrations of Dissolved Organic Carbon (DOC) and methane, irrespective of oxygen, Eh (redox) or pH. The kinetics of the microbial evolution is not yet known, and microbes may then play a role in fracture clogging which could possibly be the factor that contributes to lower groundwater inflow to underground facilities with time, as shown for many facilities. The compilation of results from the relevant tests at underground laboratories in Canada, Japan, Sweden and Switzerland was focussed on the extent of the damage and its dependency on excavation methods and measurements of the hydraulic properties. The most important factor controlling the excavation damage is the choice of excavation method. Use of mechanical excavation may create irreversible damage less than 30 mm from the rock wall where increased micro-fracturing contributes to an increase in hydraulic conductivity. Several methods and sample scales have been used to characterise the damage zone. For a Tunnel Boring Machine < 5 mm of damage was recorded at Aespoe HRL and at Grimsel in Switzerland. The hydraulic conductivity was at e.g. Aespoe HRL determined to be in the range of 10-9 m/s over a distance of 1-2 mm from the tunnel

  16. Tunnel and Station Cost Methodology : Mined Tunnels (United States)


    The main objective of this study was to develop a model for estimating the cost of subway station and tunnel construction. This report describes a cost estimating methodology for subway tunnels that can be used by planners, designers, owners, and gov...

  17. Numerical modeling of tunneling induced ground deformation and its control

    Directory of Open Access Journals (Sweden)

    V B Maji


    Full Text Available Tunnelling through cities underlain by soft soil, commonly associated with soil movement around the tunnels and subsequent surface settlement. The predication of ground movement during the tunnelling and optimum support pressure could be based on analytical, empirical or the numerical methods. The commonly used Earth pressure balance (EPB tunneling machines, uses the excavated soil in a pressurised head chamber to apply a support pressure to the tunnel face during excavation. This face pressure is a critical responsibility in EPB tunnelling because as the varying pressure can lead to collapse of the face. The objective of the present study is to evalute the critical supporting face pressure and grout pressure by observing the vertical deformation and horizontal displacement of soil body during tunneling. The face pressure and grout pressures were varied to see how they might influence the magnitude of surface settlements/heave. A numerical model using PLAXIS-3D tunnel has been developed to analyse the soil movement around the tunnel that includes various geotechnical conditions. The ground surrounding the tunnel found to be very sensitive to the face pressure and grout pressure in terms of surface settlement and collapse of the soil body.

  18. Brittle Rock Modeling Approach and its Validation Using Excavation-Induced Micro-Seismicity (United States)

    Ma, Chun-Chi; Li, Tian-Bin; Xing, Hui-Lin; Zhang, Hang; Wang, Min-Jie; Liu, Tian-Yi; Chen, Guo-Qing; Chen, Zi-Quan


    With improvements to the bonded-particle model, a custom indicator of crack intensity is introduced to grade rock fractures accurately. Brittle fracturing of rock mass is studied using the bonded-particle model; here, "brittle" refers to the process where more energy is released towards making particles collide and disperse, and hence results in the quick emergence of "chain cracks". Certain principles concerning how to construct brittle rock are then proposed. Furthermore, a modeling approach for brittle rocks based on the adaptive continuum/discontinuum (AC/DC) method is proposed to aid the construction of large-scale models of tunnel excavations. To connect with actual tunneling conditions, fundamental mechanical properties, the mechanism for brittle fracturing, the joint distribution, and the initial stress field are considered in the modeling approach. Results from micro-seismic monitoring of a tunnel excavation confirmed the suitability of this modeling approach to simulate crack behavior, and results show that simulated cracking exhibit similar trends (evolution, location, and intensity) with micro-seismic cracking.

  19. 29 CFR 1926.913 - Blasting in excavation work under compressed air. (United States)


    ... 29 Labor 8 2010-07-01 2010-07-01 false Blasting in excavation work under compressed air. 1926.913... Use of Explosives § 1926.913 Blasting in excavation work under compressed air. (a) Detonators and... use in wet holes shall be water-resistant and shall be Fume Class 1. (g) When tunnel excavation in...

  20. Surface and subsurface structural response on the City of London cable tunnels project


    Legge, N.B.; Bloodworth, A.G.


    This paper presents surface and subsurface ground and structural response to the excavation of an urban cable tunnel within London clay and the Lambeth Group strata. Project specific tunnelling volume losses were estimated and found to be dependent on face advance and geology. The presence of adjacent buildings reduced predicted ?greenfield? settlements. The tunnel passed below a continuous section comprising basements, box rail tunnels and other structures. These structures generally respond...

  1. Excavations at Wodoku and Lodoku and their implications for the ...

    African Journals Online (AJOL)

    Finds from excavations at Wodoku and Ladoku, the original home of the Nungwa and La people respectively are described, and their implications for the archaeology of the Accra Plains, particularly as they relate to the pottery sequence, Ga-Dangme origins, chronology of settlements, economy and subsistence practices ...

  2. Support system, excavation arrangement, and process of supporting an object

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, Bill W.


    A support system, an excavation arrangement, and a process of supporting an object are disclosed. The support system includes a weight-bearing device and a camming mechanism positioned below the weight-bearing device. A downward force on the weight-bearing device at least partially secures the camming mechanism to opposing surfaces. The excavation arrangement includes a borehole, a support system positioned within and secured to the borehole, and an object positioned on and supported by the support system. The process includes positioning and securing the support system and positioning the object on the weight-bearing device.

  3. Asteroid Icy Regolith Excavation and Volatile Capture Project (United States)

    Zeitlin, Nancy; Mantovani, James; Swanger, Adam; Townsend, Ivan


    Icy regolith simulants will be produced in a relevant vacuum environment using various minerals, including hydrated minerals, that are found in C-type meteorites and in other types of planetary regolith. This will allow us to characterize the mechanical strength of the icy regolith as a function of ice content using penetration, excavation, and sample capture devices. The results of this study will benefit engineers in designing efficient regolith excavators and ISRU processing systems for future exploration missions to asteroids and other planetary bodies.

  4. Tunnel support design by comparison of empirical and finite element analysis of the Nahakki tunnel in mohmand agency, pakistan (United States)

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


    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.

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

    Directory of Open Access Journals (Sweden)

    Riaz Asif


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

  6. Complete excavation and mapping of a Texas leafcutting ant nest (United States)

    John C. Moser


    A medium-sized nest of the Texas leafcutting ant, Atta texana (Buckley), in northern Louisiana was excavated completely, and a three-dimensional model of its external and subterranean features was constructed. In total, 97 fungus gardens, 27 dormancy cavities, and 45 detritus cavities were located. At the lower center of the funnel-shaped nest was a...

  7. Modelling of excavation depth and fractures in rock caused by tool indentation

    Energy Technology Data Exchange (ETDEWEB)

    Kou Shaoquan; Tan Xiangchun; Lindqvist, P.A. [Luleaa Univ. of Technology (Sweden)


    The hydraulic regime after excavation in the near-field rock around deposition holes and deposition tunnels in a spent nuclear fuel repository is of concern for prediction of the saturation process of bentonite buffer and tunnel backfill. The hydraulic condition of main interest in this context is a result of the fracture network that is caused by the excavation. Modelling of the excavation disturbed zone in hard rocks caused by mechanical excavation has been carried out in the Division of Mining Engineering since 1993. This report contains an overview of the work conducted. The mechanical excavation is reasonably simplified as an indentation process of the interaction between rigid indenters and rocks. A large number of experiments have been carried out in the laboratory, and the results used for identifying crushed zones and fracture systems in rock under indentation are presented based on these experiments. The indentation causes crushing and damage of the rock and results in a crushed zone and a cracked zone. The indenter penetrates the rock with a certain depth when the force is over a threshold value relevant to the rock and tool. Outside the cracked zone there are basically three systems of cracks: median cracks, radial cracks, and side cracks. Fully developed radial cracks on each side of the indented area can connect with each other and join with median crack. This forms the so-called radial/median crack system. The influence of the mechanical properties of the rock is discussed based on our conceptual model, and the main factors governing the indentation event are summarised. The cracked zone is dealt with by an analytical fracture model. The side crack is simulated by applying the boundary element method coupled with fracture mechanics. Functional relationships are established relating either the indentation depth or the length of radial/median cracks to the various quantities characterising the physical event, namely the shape and the size of the

  8. Telemanipulation and supervisory control of a backhoe excavator (United States)

    Luengo, Oscar; Barrientos, Antonio


    The excavation tasks present one of the more challenging area in robotic research. The environment is highly unstructured, the forces that appear are very large it is very important the detection of underground obstacles to avoid any damage, and the modeling of the hydraulic actuators is highly nonlinear. In recent years, the remote control of the excavation has found applications in very dangerous environments for human beings, like nuclear power plants, nuclear and chemical waste facilities and terrestrial and extra-terrestrial mining. Some kind of intelligence is required due to the presence of unexpected situations. The first approach to deal with the problem is to put a human being in the loop, that is: teleoperation. The next step towards the total automation of the excavation is the supervisory control of the task. In this scheme, the operator acts like a supervisor, providing high level commands, and checking the development and accomplishment of the task. The solutions that DISAM has developed are presented in this paper, as well as future work that will be very useful in the search for the total automation of excavation tasks.

  9. Analysis of mechanical behavior of soft rocks and stability control in deep tunnels

    Directory of Open Access Journals (Sweden)

    Hui Zhou


    Full Text Available Due to the weakness in mechanical properties of chlorite schist and the high in situ stress in Jinping II hydropower station, the rock mass surrounding the diversion tunnels located in chlorite schist was observed with extremely large deformations. This may significantly increase the risk of tunnel instability during excavation. In order to assess the stability of the diversion tunnels laboratory tests were carried out in association with the petrophysical properties, mechanical behaviors and water-weakening properties of chlorite schist. The continuous deformation of surrounding rock mass, the destruction of the support structure and a large-scale collapse induced by the weak chlorite schist and high in situ stress were analyzed. The distributions of compressive deformation in the excavation zone with large deformations were also studied. In this regard, two reinforcement schemes for the excavation of diversion tunnel bottom section were proposed accordingly. This study could offer theoretical basis for deep tunnel construction in similar geological conditions.

  10. Learning from case studies and monitoring of Dutch tunnel projects

    NARCIS (Netherlands)

    Korff, M.


    Individuals and project-based organisations in the construction industry can learn in a (more) systematic way from case studies and the monitoring of underground construction works. Underground construction projects such as tunnels and excavations suffer as much or more from failure costs

  11. Excavation multiple up drafting tunnels in coastal mountains: A simple solution to resist against the severe drought in sub tropical zones (United States)

    Daei, Mohammad Ali; Daei, Manizheh; Daei, Bijan


    At many sub tropical places in the globe, including the Persian Gulf in the south of Iran, there is continuously a tremendous amount of steam in the air, but it fails to transform to cloud because of the surrounding overheated lands. Reduction in precipitation in these regions has been extraordinary in recent years. The most probable reason is the global warming phenomena. Many dried forest remains, in these regions are referring to much more precipitations not long ago. All around the Persian Gulf, Oman Sea, Arab sea, and red sea there are enough steam to produce good precipitation nearly year round. The main missed requirement in this zone is the coldness. This fact can be well understand from a narrow green strip in Dhofar which is indebted to a cold oceanic stream that approaches to local shore during four months yearly. This natural cold stream helps a better condensation of water vapor and more precipitation but only in a narrow mountainous land. Based on this natural phenomenon, we hypothesize a different design to cool the water vapor with the same result. Prevention of close contact between the water vapors and hot lands by shooting the steam directly into the atmosphere may help to produce more cloud and rain. Making multiple vertical tunnels in mountains for upright conducting of humid air into the atmosphere can be a solution. Fortunately there are a few high mountain ranges alongside of the coastline in south part of Iran. So excavation of drafting tunnels in these mountains seems reasonable. These structures act passively, but for long term do their work without consuming energy, and making pollution. These earth tubes in some aspects resemble to Kariz, another innovative structure which invented by ancient Iranians, thousands of years ago in order to extract water from dry lands in deserts. Up drafting earth channels can be supposed as a wide vertical kariz which conduct water vapor into the atmosphere from the hot land near a warm sea, something

  12. Applicability of tunnel boring Machine and its expert system. Tunnel kusshinki no tekiyosei to expert system

    Energy Technology Data Exchange (ETDEWEB)

    Okubo, S. (Univ. of Tokyo, Tokyo (Japan). Faculty of Engineering)


    A tunnel boring machine (TBM) shows extreme lowering in mean penetration rate if it is not properly applied and used, therefore, it is required to discuss the applicability of TBM in advance. In this papaer, the work results presented up to now and knowledge concerning to TBM performances are collected and implemented in a computer program which is called an expert system for applicability of TBM. In this expert system, input parameters are tunnel length, tunnel diameter, maximum curvature, dip, uniaxial compressive strength etc., and penetration rate, normal force, rolling force etc. are deduced together with the appraisal and recommendation for users. Through the several case studies, it was found that the developed expert system gives the appropriate results specially for the tunnels excavated in North America and Europe. In cases of tunnels excavated in Japan, the estimated penetration rate is far less than the actual result. Consideration for complicated environments and surroundings differing from country to country may be remained for future. 31 refs., 4 figs., 6 tabs.

  13. Digging the termite way: crowding simple robots to excavate ramification structures (United States)

    Bardunias, Paul

    The complex ramification network that termites excavate in soil in search of resources has been shown to emerge from interactions between individuals during periodic crowding at the tips of tunnels. Excavation in these social insects is carried out by a rotation of termites removing soil from the tip of an expanding tunnel and depositing it back along the tunnel walls. Bristle bots, modified to either rock or turn on contact with soil in an artificial tunnel, were used to replicate this process. As in termites, congestion at tunnel tips leads to the widening and branching of tunnels.

  14. Numerical Simulation and Monitoring of Surface Environment Influence of Waterless Sand Layer Shield Tunneling (United States)

    Shang, Yanliang; Han, Tongyin; Shi, Wenjun; Du, Shouji; Qin, Zhichao


    The development of urban subway is becoming more and more rapid and plays an increasingly important role. The shield tunneling method has become the first choice for the construction of urban subway tunnel in the construction of urban subway. The paper takes the interval of Shijiazhuang Metro Line 3 Administrative Center Station and Garden Park Station as the engineering background. The establishment of double shield finite difference model by considering the thickness of covering soil, tunnel excavation and excavation at the same time, distance and other factors, the surface deformation, and soil thickness. The ground deformation law is obtained, the surface settlement is inversely proportional to the overburden thickness and the double line spacing, and the gradual excavation is smaller than the synchronous excavation.

  15. Emergency Survey and Excavation in Southwestern New Mexico. (United States)


    Period 90 * The Apache 90 The Spanish, Mexican, and American Occupations 90 ii *li APPENDIX B - BOTANICAL RIMAIS 92 Mollie Struever and Marcia Donaldson...probably the scene of seasonal mesquite-gathering and hunting expeditions. The Cochise Cul- ture is also known from Tularosa and Cordova Caves near the upper... Cordova Caves (Martin and Rinaldo 1952). Additional chronology was provided by excavations in Bat Cave (Dick 1965). Tentatively dated at 300 B.C., the



    Zvonimir Deković; Zvonimir Ester; Mario Dobrilović


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

  17. Soil Lysimeter Excavation for Coupled Hydrological, Geochemical, and Microbiological Investigations. (United States)

    Sengupta, Aditi; Wang, Yadi; Meira Neto, Antonio A; Matos, Katarena A; Dontsova, Katerina; Root, Rob; Neilson, Julie W; Maier, Raina M; Chorover, Jon; Troch, Peter A


    Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled Earth-system processes. Such knowledge is imperative in improving predictions of hydro-biogeochemical cycles, especially under climate change scenarios. We present an experimental method, designed to capture sub-surface heterogeneity of an initially homogeneous soil system. This method is based on destructive sampling of a soil lysimeter designed to simulate a small-scale hillslope. A weighing lysimeter of one cubic meter capacity was divided into sections (voxels) and was excavated layer-by-layer, with sub samples being collected from each voxel. The excavation procedure was aimed at detecting the incipient heterogeneity of the system by focusing on the spatial assessment of hydrological, geochemical, and microbiological properties of the soil. Representative results of a few physicochemical variables tested show the development of heterogeneity. Additional work to test interactions between hydrological, geochemical, and microbiological signatures is planned to interpret the observed patterns. Our study also demonstrates the possibility of carrying out similar excavations in order to observe and quantify different aspects of soil-development under varying environmental conditions and scale.

  18. Risk of shear failure and extensional failure around over-stressed excavations in brittle rock

    Directory of Open Access Journals (Sweden)

    Nick Barton


    Full Text Available The authors investigate the failure modes surrounding over-stressed tunnels in rock. Three lines of investigation are employed: failure in over-stressed three-dimensional (3D models of tunnels bored under 3D stress, failure modes in two-dimensional (2D numerical simulations of 1000 m and 2000 m deep tunnels using FRACOD, both in intact rock and in rock masses with one or two joint sets, and finally, observations in TBM (tunnel boring machine tunnels in hard and medium hard massive rocks. The reason for ‘stress-induced’ failure to initiate, when the assumed maximum tangential stress is approximately (0.4–0.5σc (UCS, uniaxial compressive strength in massive rock, is now known to be due to exceedance of a critical extensional strain which is generated by a Poisson's ratio effect. However, because similar ‘stress/strength’ failure limits are found in mining, nuclear waste research excavations, and deep road tunnels in Norway, one is easily misled into thinking of compressive stress induced failure. Because of this, the empirical SRF (stress reduction factor in the Q-system is set to accelerate as the estimated ratio σθmax/σc >> 0.4. In mining, similar ‘stress/strength’ ratios are used to suggest depth of break-out. The reality behind the fracture initiation stress/strength ratio of ‘0.4’ is actually because of combinations of familiar tensile and compressive strength ratios (such as 10 with Poisson's ratio (say 0.25. We exceed the extensional strain limits and start to see acoustic emission (AE when tangential stress σθ ≈ 0.4σc, due to simple arithmetic. The combination of 2D theoretical FRACOD models and actual tunnelling suggests frequent initiation of failure by ‘stable’ extensional strain fracturing, but propagation in ‘unstable’ and therefore dynamic shearing. In the case of very deep tunnels (and 3D physical simulations, compressive stresses may be too high for extensional strain fracturing, and

  19. Lightweight Robotic Excavation Project (United States)

    National Aeronautics and Space Administration — Robust, lightweight, power-efficient excavation robots are mission enablers for lunar outposts and surface systems. Lunar excavators of this type cost-effectively...

  20. Silica exposure to excavation workers during the excavation of a low level radiological waste pit and tritium disposal shafts

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, K.M.


    This study evaluated the task-length average (TLA) respirable dust and respirable silica airborne concentrations to which construction workers excavating volcanic tuff at Los Alamos National Laboratory (LANL) were exposed. These workers were excavating a low level radiological waste disposal pit of final dimensions 720 feet long, 132 feet wide and 60 feet deep. The objectives of this study were as follows: (1) evaluate exposures; (2) determine if the type of machinery used affects the respirable dust concentration in the breathing zone of the worker; (3) evaluate the efficacy of wetting the pit to reduce the respirable dust exposure; and (4) determine if exposure increases with increasing depth of pit due to the walls of the pit blocking the cross wind ventilation.

  1. Focal Choroidal Excavation. (United States)

    Cebeci, Zafer; Bayraktar, Şerife; Oray, Merih; Kır, Nur


    Focal choroidal excavation is a choroidal pit that can be detected by optical coherence tomography. Central serous chorioretinopathy, choroidal neovascularization and polypoidal choroidal vasculopathy are pathologies associated with focal choroidal excavation. In this article, we present the follow-up and treatment outcomes of three eyes of two patients with focal choroidal excavation.

  2. Target and Projectile: Material Effects on Crater Excavation and Growth (United States)

    Anderson, J. L. B.; Burleson, T.; Cintala, Mark J.


    Scaling relationships allow the initial conditions of an impact to be related to the excavation flow and final crater size and have proven useful in understanding the various processes that lead to the formation of a planetary-scale crater. In addition, they can be examined and tested through laboratory experiments in which the initial conditions of the impact are known and ejecta kinematics and final crater morphometry are measured directly. Current scaling relationships are based on a point-source assumption and treat the target material as a continuous medium; however, in planetary-scale impacts, this may not always be the case. Fragments buried in a megaregolith, for instance, could easily approach or exceed the dimensions of the impactor; rubble-pile asteroids could present similar, if not greater, structural complexity. Experiments allow exploration into the effects of target material properties and projectile deformation style on crater excavation and dimensions. This contribution examines two of these properties: (1) the deformation style of the projectile, ductile (aluminum) or brittle (soda-lime glass) and (2) the grain size of the target material, 0.5-1 mm vs. 1-3 mm sand.


    Directory of Open Access Journals (Sweden)

    Zvonimir Deković


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

  4. Kirke Hyllinge and Snesere - Romanesque Twin Towers Recently Excavated

    DEFF Research Database (Denmark)

    Rensbro, Henriette; Vedsø, Mogens


    Mirator, 2015. Co-author: Mogens Vedsø. Romanesque twin towers in Danish village churches have long tradition of research. Two recent excavations in Kirke Hyllinge and Snesere have revealed archaeological traces of rectangular towers which in this article are compared to other examples from Denmark....... Kirke Hyllinge church is an outstanding example of twin towers due to the length of the west-section of 16 meters. The only parallel is a planned three-aisled village church in the other end of the country. While for Snesere church the main question is the design of the top section, whether...... it was a twin tower or not....

  5. Parametric Optimization and Prediction Tool for Excavation and Prospecting Tasks Project (United States)

    National Aeronautics and Space Administration — Honeybee Robotics therefore proposed to develop a software tool for facilitating prospecting and excavation system trades in support of selecting an optimal...

  6. The Beginner's Guide to Wind Tunnels with TunnelSim and TunnelSys (United States)

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


    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.

  7. Evaluation of bending moment and deflection of cantilever supported excavations

    Directory of Open Access Journals (Sweden)

    Seyed Hamid Yasrebi


    Full Text Available In many conditions, because of several restrictions, cantilever walls are the only way to stabilize the excavations. It is no doubt that one of the most important parameters in design of such walls is wall stiffness. Therefore, in this study, a large number of case histories are collected and the most commonly used range of wall thickness and stiffness are determined based on this database. In addition, validation of limit equilibrium method (LEM in granular soils showed that this method can only estimate bending moment of rigid walls. Therefore, for more accurate estimating, a new equation is presented for the most commonly used range of wall stiffness and various types of granular soils. Moreover, LEM based equation is replaced with a modified version. The new equation was successfully validated using 70 numerical models and results lied in range of 85% to 115% times the predicted values obtained from FEM. According to the results, in loose and very loose soils, the common cantilever walls can only stabilize the excavations with depth less than 10 m. While if depth is more than 15 m, soil type should be dense or very dense with “E” more than about 70 MPa. The results also show that the effect of wall stiffness is negligible in bending moments less than 2000 kN.m.

  8. Environmental problems caused by Istanbul subway excavation and suggestions for remediation (United States)

    Ocak, Ibrahim


    Many environmental problems caused by subway excavations have inevitably become an important point in city life. These problems can be categorized as transporting and stocking of excavated material, traffic jams, noise, vibrations, piles of dust mud and lack of supplies. Although these problems cause many difficulties, the most pressing for a big city like Istanbul is excavation, since other listed difficulties result from it. Moreover, these problems are environmentally and regionally restricted to the period over which construction projects are underway and disappear when construction is finished. Currently, in Istanbul, there are nine subway construction projects in operation, covering approximately 73 km in length; over 200 km to be constructed in the near future. The amount of material excavated from ongoing construction projects covers approximately 12 million m3. In this study, problems—primarily, the problem with excavation waste (EW)—caused by subway excavation are analyzed and suggestions for remediation are offered.

  9. Collective workload organization in confined excavation of granular media (United States)

    Monaenkova, Daria; Linevich, Vadim; Goodisman, Michael A.; Goldman, Daniel I.


    Many social insects collectively construct large nests in complex substrates; such structures are often composed of narrow tunnels. The benefits of collective construction, including reduced construction costs per worker come with challenges of navigation in crowded, confined spaces. Here we study the workforce organization of groups of S. invicta fire ants creating tunnels in wet granular media. We monitor the activity levels of marked (painted) workers-defined as a number of tunnel visits over 12 hours- during initiation of tunnels. The activity levels are described by a Lorenz curve with a Gini coefficient of ~ 0 . 7 indicating that a majority of the excavation is performed by a minority of workers. We hypothesize that this workload distribution is beneficial for excavation in crowded conditions, and use a 2D cellular automata (CA) model to reproduce behaviors of the excavating ants. CA simulations reveal that tunnel construction rates decrease in groups of equally active animals compared to groups with the natural workload distribution. We use predictions of the CA model to organize collective excavation of granular material by teams of digging robots, and use the robots to test hypotheses of crowded excavation in the physical world. We acknowledge support of National Science Foundation, Physics of Living Systems division.

  10. Performance characteristics of tunnel boring machine in basalt and pyroclastic rocks of Deccan traps – A case study

    Directory of Open Access Journals (Sweden)

    Prasnna Jain


    Full Text Available A 12.24 km long tunnel between Maroshi and Ruparel College is being excavated by tunnel boring machine (TBM to improve the water supply system of Greater Mumbai, India. In this paper, attempt has been made to establish the relationship between various litho-units of Deccan traps, stability of tunnel and TBM performances during the construction of 5.83 km long tunnel between Maroshi and Vakola. The Maroshi–Vakola tunnel passes under the Mumbai Airport and crosses both runways with an overburden cover of around 70 m. The tunneling work was carried out without disturbance to the ground. The rock types encountered during excavation are fine compacted basalt, porphyritic basalt, amygdaloidal basalt, pyroclastic rocks with layers of red boles and intertrappean beds consisting of various types of shales. Relations between rock mass properties, physico-mechanical properties, TBM specifications and the corresponding TBM performance were established. A number of support systems installed in the tunnel during excavation were also discussed. The aim of this paper is to establish, with appropriate accuracy, the nature of subsurface rock mass condition and to study how it will react to or behave during underground excavation by TBM. The experiences gained from this project will increase the ability to cope with unexpected ground conditions during tunneling using TBM.

  11. Groundwater flow modelling of the excavation and operational phases - Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Urban (Computer-aided Fluid Engineering AB, Lyckeby (Sweden)); Rhen, Ingvar (SWECO Environment AB, Falun (Sweden))


    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. The modelling study reported here presents calculated inflow rates, drawdown of the groundwater table and upconing of deep saline water for different levels of grouting efficiency during the excavation and operational phases of a final repository at Laxemar. The inflow calculations were accompanied by a sensitivity study, which among other matters handled the impact of different deposition hole rejection criteria. The report also presents tentative modelling results for the duration of the saturation phase, which starts once the used parts of the repository are being backfilled

  12. Pajarito Plateau archaeological survey and excavations. [Los Alamos Reservation

    Energy Technology Data Exchange (ETDEWEB)

    Steen, C.R.


    Los Alamos Scientific Laboratory lands were surveyed to locate pre-Columbian Indian ruins. The survey results will permit future construction to be planned so that most of the ancient sites in the area can be preserved. Indian occupation of the area occurred principally from late Pueblo III times (late 13th century) until early Pueblo V (about the middle of the 16th century). There are evidences of sporadic Indian use of the area for some 10,000 years. One Folsom point has been found, as well as many other archaic varieties of projectile points. Continued use of the region well into the historic period is indicated by pictographic art that portrays horses. In addition to an account of the survey, the report contains summaries of excavations made on Laboratory lands between 1950 and 1975.

  13. Dam geology and basic treatment(2). Adit substitution technique and measures against landslide involved in excavation

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Kin' ichi (Kinki Geological Center, Co. Ltd., Kyoto, Japan (JP))


    This paper discusses the adit substitution technique which is a method for special treatment of dams and measures against landslide involved in excavation. The adit substitution technique consists of excavating an adit in the natural ground, excavating another adit which is in contact with the first adit and is at a level higher than the first adit, placing concrete from the upper adit to the lower adit to fill first adit completely with concrete, excavating a third adit, filling the second adit with concrete similarly, and proceeding with this process to construct a water barrier within the natural ground until the water barrier reaches the required height. The paper explains examples of this technique used on four dams. It also explains examples of measures against excavation-induced landslide adopted on three dams. 13 refs., 8 figs., 2 tabs.

  14. Key Techniques and Risk Management for the Application of the Pile-Beam-Arch (PBA) Excavation Method: A Case Study of the Zhongjie Subway Station (United States)

    Guan, Yong-ping; Zhao, Wen; Li, Shen-gang; Zhang, Guo-bin


    The design and construction of shallow-buried tunnels in densely populated urban areas involve many challenges. The ground movements induced by tunneling effects pose potential risks to infrastructure such as surface buildings, pipelines, and roads. In this paper, a case study of the Zhongjie subway station located in Shenyang, China, is examined to investigate the key construction techniques and the influence of the Pile-Beam-Arch (PBA) excavation method on the surrounding environment. This case study discusses the primary risk factors affecting the environmental safety and summarizes the corresponding risk mitigation measures and key techniques for subway station construction using the PBA excavation method in a densely populated urban area. PMID:25221783

  15. Deformations and damage to buildings adjacent to deep excavations in soft soils

    NARCIS (Netherlands)

    Korff, M.


    The objective of this study is to gain insight into mechanisms of soil-structure interaction for buildings adjacent to deep excavations and to find a reliable method to design and monitor deep excavations in urban areas with soft soil conditions. The research focuses on typical Dutch conditions. The

  16. Road and Railroad Tunnels (United States)

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

  17. Clinical and optic coherence tomography findings of focal choroidal excavation in Chinese patients. (United States)

    Guo, Jie; Zhong, Lu; Jiang, Chunhui; Zhou, Xin; Xu, Gezhi; Wang, Wenji; Wang, Yuliang


    To describe the clinical and optical coherence tomography (OCT) features of focal choroidal excavation in Chinese patients. Retrospectively, thirty-seven eyes (in 31 patients) that demonstrated focal choroidal excavation on spectral-domain OCT were collected. Their clinical characteristics and other features were also collected and analyzed. In total, 42 focal choroidal excavations were identified in 31 patients, including 25 unilateral and 6 bilateral (37 eyes). The abnormal changes in these eyes with choroidal excavation were more prominent at the outer part of the neuro-retina, the retinal pigment epithelium (RPE) and the choroid. The average transverse diameter and depth of the excavations were 670.8 μm and 106.9 μm, respectively. In addition to the conforming and nonconforming types, the excavations could also be classified into 2 types according to their shape: type 1 - small with a sharp, cut-down contour; and type 2 - slightly larger with a gradual edge. The transverse diameter/depth ratio of the two types were significantly different (type1: 4.57 ± 1.65, type 2: 10.0 ± 5.2; p = 0.000). Four central serous chorioretinopathy (CSCR) cases were confirmed by fluorescein angiography; in these cases, the retinal detachment was larger than the area of excavation, and the inner segment/outer segment (IS/OS) and external limiting membrane (ELM) were above those of the normal part. Concomitant CNV was also found in another 2 cases. Focal choroidal excavation was not uncommon in Chinese patients. The choroid and the RPE at the excavation were impaired or vulnerable to other damage. Additionally, OCT might be useful in the differentiation between nonconforming excavations and ones with CSCR.

  18. Dye staining and excavation of a lateral preferential flow network

    Directory of Open Access Journals (Sweden)

    A. E. Anderson


    Full Text Available Preferential flow paths have been found to be important for runoff generation, solute transport, and slope stability in many areas around the world. Although many studies have identified the particular characteristics of individual features and measured the runoff generation and solute transport within hillslopes, very few studies have determined how individual features are hydraulically connected at a hillslope scale. In this study, we used dye staining and excavation to determine the morphology and spatial pattern of a preferential flow network over a large scale (30 m. We explore the feasibility of extending small-scale dye staining techniques to the hillslope scale. We determine the lateral preferential flow paths that are active during the steady-state flow conditions and their interaction with the surrounding soil matrix. We also calculate the velocities of the flow through each cross-section of the hillslope and compare them to hillslope scale applied tracer measurements. Finally, we investigate the relationship between the contributing area and the characteristics of the preferential flow paths. The experiment revealed that larger contributing areas coincided with highly developed and hydraulically connected preferential flow paths that had flow with little interaction with the surrounding soil matrix. We found evidence of subsurface erosion and deposition of soil and organic material laterally and vertically within the soil. These results are important because they add to the understanding of the runoff generation, solute transport, and slope stability of preferential flow-dominated hillslopes.

  19. Groundwater flow modelling of the excavation and operational phases - Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Urban (Computer-aided Fluid Engineering AB, Lyckeby (Sweden)); Follin, Sven (SF GeoLogic AB, Taeby (Sweden))


    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different climate conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. The modelling study reported here presents calculated inflow rates, drawdown of the groundwater table and upconing of deep saline water for different levels of grouting efficiency during the excavation and operational phases of a final repository at Forsmark. The inflow calculations are accompanied by a sensitivity study, which among other matters handles the impact of parameter heterogeneity, different deposition hole rejection criteria, and the SFR facility (the repository for short-lived radioactive waste located approximately 1 km to the north of the investigated candidate area for a final repository at Forsmark). The report also presents tentative modelling results for the duration of the saturation phase, which starts once the used parts of the repository are being backfilled.


    Simhaee, Daniel; Dolz-Marco, Rosa; Freund, K Bailey


    To report two cases of choroidal nevi associated with focal choroidal excavation (FCE) and polypoidal choroidal neovascularization (PCN). Report of two patients with choroidal nevi showing FCE and PCN who underwent multimodal imaging including color fundus photography, fluorescein angiography, indocyanine green angiography, fundus autofluorescence, spectral domain optical coherence tomography, swept-source optical coherence tomography, and optical coherence tomography angiography. Two patients presented with choroidal nevi associated with FCE and PCN. In the first case, a 74-year-old woman, the nevus had sharp margins, a deep FCE, surrounding drusen, and subretinal exudation at its inferior edge due to PCN that responded well to intravitreal anti-vascular endothelial growth factor therapy. In the second case, a 64-year-old woman, the nevus had ill-defined margins, a shallow FCE, and angiographic evidence of PCN without associated exudation. There have been several reports showing an association of either choroidal nevi or FCE with PCN. To our knowledge, there have been no previous reports of FCE identified within choroidal nevi, with or without associated PCN. Since, in one of our cases, the FCE was not apparent on clinical examination, the prevalence of FCE within nevi may be underdiagnosed.

  1. In-situ stress amplification due to geological factors in tunnels: The case of Pajares tunnels, Spain


    Hijazo Ramiro, Teresa; González de Vallejo, Luis I.


    Geological and geomechanical anisotropies can significantly increase the magnitude of in-situ stress in a rock mass excavated for tunnelling purposes. Four tunnels for the new high-speed railway lines in Pajares in the Cantabrian Mountains, N. Spain, were analysed and significant deformations was found to have occurred in forty specific zones of these tunnels during excavation, requiring much more support than envisaged before construction. Local factors influencing in-situ stress...

  2. POEM and Submucosal Tunneling. (United States)

    Werner, Yuki B; Rösch, Thomas


    Submucosal endoscopy has introduced new and important aspects into gastrointestinal endoscopic therapeutics by opening the way to interventions even outside of the GI tract. At present, innovative techniques for submucosal endoscopy in different esophageal diseases include peroral endoscopic myotomy (POEM) for idiopathic achalasia and related motility disorders, submucosal tunneling endoscopic resection (STER) for submucosal tumors arising from the muscularis propria, and endoscopic submucosal tunneling dissection (ESTD) for superficial esophageal neoplastic lesions. POEM for achalasia-still a rare disease-is currently evaluated in comparison to endoscopic and surgical standard therapies, while this procedure enabling a long thoracic myotomy might constitute an advantage over the laparoscopic approach in treatments of spastic esophageal diseases. Removal of smaller submucosal esophageal tumors may appear tempting, but the clinical indications are limited by the facts that the vast majority of such smaller tumors are asymptomatic and benign.For all these innovative and technically demanding techniques, learning curves have to be taken into account, not only with regard to technical competence but also to clinical assessment, ranging from proper indication and patient selection to the management of (potential) complications and logistics/back-up. Although preliminary results from high-skilled endoscopic centers have been very encouraging, long-term data as well as prospective randomized controlled trials are needed to validate the efficacy and safety of the modalities.

  3. Exploration and excavation of shipwrecks in Goa and adjoining waters 2005-2006

    Digital Repository Service at National Institute of Oceanography (India)

    As a part of the institutional project, 'Application of Geological and Geophysical methods in Marine Archaeology and Underwater Explorations, (OLP 0008)', exploration and excavation of shipwrecks have been carried out from 23 Jan 2006 to 21 Feb 2006...

  4. Analysis of rockburst in tunnels subjected to static and dynamic loads

    Directory of Open Access Journals (Sweden)

    Amin Manouchehrian


    Full Text Available The presence of geological structures such as faults, joints, and dykes has been observed near excavation boundaries in many rockburst case histories. In this paper, the role of discontinuities around tunnels in rockburst occurrence was studied. For this purpose, the Abaqus explicit code was used to simulate dynamic rock failure in deep tunnels. Material heterogeneity was considered using Python scripting in Abaqus. Rockbursts near fault regions in deep tunnels under static and dynamic loads were studied. Several tunnel models with and without faults were built and static and dynamic loads were used to simulate rock failure. The velocity and the released kinetic energy of failed rocks, the failure zone around the tunnel, and the deformed mesh were studied to identify stable and unstable rock failures. Compared with models without discontinuities, the results showed that the velocity and the released kinetic energy of failed rocks were higher, the failure zone around the tunnel was larger, and the mesh was more deformed in the models with discontinuities, indicating that rock failure in the models with discontinuities was more violent. The modeling results confirm that the presence of geological structures in the vicinity of deep excavations could be one of the major influence factors for the occurrence of rockburst. It can explain localized rockburst occurrence in civil tunnels and mining drifts. The presented methodology in this paper for rockburst analysis can be useful for rockburst anticipation and control during mining and tunneling in highly stressed ground.

  5. 76 FR 19129 - Excavations (Design of Cave-in Protection Systems); Extension of the Office of Management and... (United States)


    ... Occupational Safety and Health Administration Excavations (Design of Cave-in Protection Systems); Extension of... information collection requirements contained in the Standard on Excavations (Design of Cave-in Protection... use protective systems to prevent cave-ins during excavation work; these systems include sloping the...

  6. Early Childhood: Funnels and Tunnels. (United States)

    Fowlkes, Mary Anne


    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)

  7. Focal choroidal excavation-morphological features and clinical correlation. (United States)

    Chung, C Y; Li, S H; Li, K K W


    PurposeTo describe and correlate the morphological and clinical features of focal choroidal excavation (FCE).MethodsThis is a consecutive case series from the review of the 4436 optical coherence tomography scans performed by Kowloon East Cluster Ophthalmic Service from 1 August 2014-31 January 2016. Statistical analysis was performed on SPSS 18.0 (SPSS, Chicago, IL, USA). A significance level of P<0.05 was taken.ResultsAll 16 patients with FCE had unilateral involvement. The mean age of diagnosis was 52.56±14.00. The mean greatest linear dimension (GLD) of FCE was 636.25±265.11 μm. The mean choroidal thickness was 183.63±52.39 μm. Fourteen FCEs (87.5%) were conforming and two were non-conforming (12.5%). In the eyes with FCE, concurrent macular pathology was present in four cases (25.0%). Tractional pathologies of macular pucker and macular scar corresponded to the two non-conforming FCEs in the series. Polypoidal choroidal vasculopathy (PCV) and lacquer crack had a close topographic relationship with the FCE. The mean GLD was significantly larger in eyes with concurrent macular pathology than those without (878.00 vs 555.67 μm, P=0.029). In the fellow eyes, concurrent macular pathology was present in 5 cases (31.3%): PCV in 3 cases and chronic central serous chorioretinopathy in 2 cases.ConclusionAs a significant proportion of FCE is associated with concurrent macular pathology in the involved or fellow eye, angiography for both eyes is recommended even for asymptomatic cases. The GLD of FCE may have clinical value in risk stratification.

  8. Analysis of labour accidents in tunnel construction and introduction of prevention measures. (United States)

    Kikkawa, Naotaka; Itoh, Kazuya; Hori, Tomohito; Toyosawa, Yasuo; Orense, Rolando P


    At present, almost all mountain tunnels in Japan are excavated and constructed utilizing the New Austrian Tunneling Method (NATM), which was advocated by Prof. Rabcewicz of Austria in 1964. In Japan, this method has been applied to tunnel construction since around 1978, after which there has been a subsequent decrease in the number of casualties during tunnel construction. However, there is still a relatively high incidence of labour accidents during tunnel construction when compared to incidence rates in the construction industry in general. During tunnel construction, rock fall events at the cutting face are a particularly characteristic of the type of accident that occurs. In this study, we analysed labour accidents that possess the characteristics of a rock fall event at a work site. We also introduced accident prevention measures against rock fall events.

  9. Parametric Optimization and Prediction Tool for Lunar Surface Systems Excavation Tasks Project (United States)

    National Aeronautics and Space Administration — Honeybee Robotics proposes to develop a software tool for facilitating lunar excavation system trades in support of selecting an optimal architecture. This will...

  10. Parameter Calibration and Numerical Analysis of Twin Shallow Tunnels (United States)

    Paternesi, Alessandra; Schweiger, Helmut F.; Scarpelli, Giuseppe


    Prediction of displacements and lining stresses in underground openings represents a challenging task. The main reason is primarily related to the complexity of this ground-structure interaction problem and secondly to the difficulties in obtaining a reliable geotechnical characterisation of the soil or the rock. In any case, especially when class A predictions fail in forecasting the system behaviour, performing class B or C predictions, which rely on a higher level of knowledge of the surrounding ground, can represent a useful resource for identifying and reducing model deficiencies. The case study presented in this paper deals with the construction works of twin-tube shallow tunnels excavated in a stiff and fine-grained deposit. The work initially focuses on the ground parameter calibration against experimental data, which together with the choice of an appropriate constitutive model plays a major role in the assessment of tunnelling-induced deformations. Since two-dimensional analyses imply initial assumptions to take into account the effect of the 3D excavation, three-dimensional finite element analyses were preferred. Comparisons between monitoring data and results of numerical simulations are provided. The available field data include displacements and deformation measurements regarding both the ground and tunnel lining.

  11. Modelling of tunnelling processes and rock cutting tool wear with the particle finite element method (United States)

    Carbonell, Josep Maria; Oñate, Eugenio; Suárez, Benjamín


    Underground construction involves all sort of challenges in analysis, design, project and execution phases. The dimension of tunnels and their structural requirements are growing, and so safety and security demands do. New engineering tools are needed to perform a safer planning and design. This work presents the advances in the particle finite element method (PFEM) for the modelling and the analysis of tunneling processes including the wear of the cutting tools. The PFEM has its foundation on the Lagrangian description of the motion of a continuum built from a set of particles with known physical properties. The method uses a remeshing process combined with the alpha-shape technique to detect the contacting surfaces and a finite element method for the mechanical computations. A contact procedure has been developed for the PFEM which is combined with a constitutive model for predicting the excavation front and the wear of cutting tools. The material parameters govern the coupling of frictional contact and wear between the interacting domains at the excavation front. The PFEM allows predicting several parameters which are relevant for estimating the performance of a tunnelling boring machine such as wear in the cutting tools, the pressure distribution on the face of the boring machine and the vibrations produced in the machinery and the adjacent soil/rock. The final aim is to help in the design of the excavating tools and in the planning of the tunnelling operations. The applications presented show that the PFEM is a promising technique for the analysis of tunnelling problems.

  12. Dynamical tunneling theory and experiment

    CERN Document Server

    Keshavamurthy, Srihari


    A prominent aspect of quantum theory, tunneling arises in a variety of contexts across several fields of study, including nuclear, atomic, molecular, and optical physics and has led to technologically relevant applications in mesoscopic science. Exploring mechanisms and consequences, Dynamical Tunneling: Theory and Experiment presents the work of international experts who discuss the considerable progress that has been achieved in this arena in the past two decades.Highlights in this volume include:A historical introduction and overview of dynamical tunneling, with case histories ranging from

  13. Smart Calibration of Excavators

    DEFF Research Database (Denmark)

    Bro, Marie; Døring, Kasper; Ellekilde, Lars-Peter


    Excavators dig holes. But where is the bucket? The purpose of this report is to treat four different problems concerning calibrations of position indicators for excavators in operation at concrete construction sites. All four problems are related to the question of how to determine the precise...... geographic and/or site-relative position of a given excavator and its bucket. However, our presentations and solutions to the problems can, nevertheless, be read and studied in any order and independently of each other. This also implies and induces a gentle warning to the reader: The {\\em{notation}} need...

  14. Use of the {sup 14}C-PMMA and He-gas methods to characterise excavation disturbance in crystalline rock

    Energy Technology Data Exchange (ETDEWEB)

    Autio, J.; Kirkkomaeki, T. [Saanio and Riekkola Oy, Helsinki (Finland); Siitari-Kauppi, M. [University of Helsinki (Finland). Lab. of Radiochemistry; Timonen, J.; Laajalahti, M.; Aaltonen, T.; Maaranen, J. [University of Jyvaeskylae (Finland). Dept. of Physics


    Characterisation of the excavation disturbance caused by boring of experimental full-scale deposition holes in the Research Tunnel at Olkiluoto was carried out successfully by using two novel methods; the {sup 14}C-PMMA and He-gas methods, which were modified and applied for the first time in this type of study. The experience obtained implies that the techniques are feasible and can be used to study similar types of rock excavation disturbance such as that caused by boring with mini discs, a technique which will be used in the underground Hard Rock Laboratory at Aespoe during late 1998 and early 1999. Both of the measurement methods have been in continuous use and the work has included development of both the measuring and interpretation techniques. Use of the {sup 14}C-PMMA method is suggested for studies of rock structure and the spatial distribution of porosity. The {sup 14}C-PMMA method also provides quantitative information about nanometer-range porosity which is beyond the scope of most standard methods of microscopic investigation. The use of He-gas methods are proposed for determining the diffusion coefficient, permeability and complementary porosity of rock samples taken from the disturbed zone. (orig.) 23 refs.

  15. The application of high resolution fluxgate gradiometery as an aid to excavation planning and strategy formulation

    Directory of Open Access Journals (Sweden)

    James Lyall


    Full Text Available The excavation of the Late Roman and Anglian settlement at West Heslerton, North Yorkshire, has been one of the largest excavations undertaken in England in the last twenty years. It has been the setting for a number of developments and experiments in the application of 'the new technology' to field archaeology. Parts of the site, which extended over c.20 Ha., proved to have high magnetic susceptibility and were ideally suited for magnetic prospection techniques. Feature visibility contrasts were, however, frequently low and therefore a series of experiments were undertaken using high resolution fluxgate gradiometer surveys following removal of the topsoil. The results of the high resolution surveys undertaken on the cleaned excavation surface proved highly successful in providing an enhanced pre-excavation plan, adding considerable detail to the surveys undertaken prior to the start of the excavation. The careful examination of the results, using G-Sys geographic data management software, which enabled the magnetic data, finds plots and digitised plans to be fully integrated, indicated areas where stratigraphic relationships could be tested and assisted in the development and re-definition of the excavation strategy as it progressed. Following initial small area tests in 1991, nearly two hectares were documented in this way during 1995 facilitating the completion of a targeted sampling operation which ensured the completion of the excavation within the limited budget available. The approach proved highly successful and offers great potential for use on sites which have a high magnetic susceptibility and are liable to large area destruction as occurs in the case of mineral extraction or subsoil ploughing operations.

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

    CERN Document Server

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


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


    Energy Technology Data Exchange (ETDEWEB)



    After 1970 Transuranic (TRU) and suspect TRU waste was buried in the ground with the intention that at some later date the waste would be retrieved and processed into a configuration for long term storage. To retrieve this waste the soil must be removed (excavated). Sloping the bank of the excavation is the method used to keep the excavation from collapsing and to provide protection for workers retrieving the waste. The purpose of this paper is to document the minimum distance (setback) that equipment must stay from the edge of the excavation to maintain a stable slope. This evaluation examines the equipment setback distance by dividing the equipment into two categories, (1) equipment used for excavation and (2) equipment used for retrieval. The section on excavation equipment will also discuss techniques used for excavation including the process of benching. Calculations 122633-C-004, 'Slope Stability Analysis' (Attachment A), and 300013-C-001, 'Crane Stability Analysis' (Attachment B), have been prepared to support this evaluation. As shown in the calculations the soil has the following properties: Unit weight 110 pounds per cubic foot; and Friction Angle (natural angle of repose) 38{sup o} or 1.28 horizontal to 1 vertical. Setback distances are measured from the top edge of the slope to the wheels/tracks of the vehicles and heavy equipment being utilized. The computer program utilized in the calculation uses the center of the wheel or track load for the analysis and this difference is accounted for in this evaluation.

  18. Lightweight Robotic Excavation Project (United States)

    National Aeronautics and Space Administration — Lightweight robotic excavators address the need for machines that dig, collect, transport and dump lunar soil. Robust and productive small robots enable mining rich...

  19. [Distribution and health risk of HCHs and DDTs in a contaminated site with excavation]. (United States)

    Zhang, Shi-Lei; Xue, Nan-Dong; Yang, Bing; Li, Fa-Sheng; Chen, Xuan-Yu; Liu, Bo; Meng, Lei


    Air samples were collected to analyze the distribution of HCHs and DDTs around a contaminated site during its excavation. The carcinogenic risks and non-carcinogenic risks through breath exposure were studied by health risk assessment modes. The results showed that, there was an obvious seasonal variation of HCHs and DDTs in air around the excavating area. The concentrations of HCHs and DDTs were higher in winter and autumn, lower in spring and summer. The Σ HCHs concentration ranged from 5.65 ng x m(-3) to 133 ng x m(-3), and the average value was 28.6 ng x m(-3); Σ DDTs concentration ranged from 4.48 ng x m(-3) to 2 800 ng x m(-3), and the average value was 457.3 ng x m(-3) in winter. However, the Σ HCHs concentration was between 6.23 ng x m(-3) and 26.4 ng x m(-3), and the average value was 15.1 ng x m(-3) in spring; the Σ DDTs concentration was between 3.17 ng x m(-3) and 8.1 ng x m(-3), and the average value was 6.1 ng x m(-3) in summer. So the pollution could be reduced by excavating in spring and summer. The concentrations of HCHs and DDTs in the residents area were negatively correlated to the height (P excavating area were lower than the acceptable level, while the excavating process caused carcinogenic and non-carcinogenic risks to young residents to some extent. In order to decrease the risks, measures should be taken to restrain the pollutants in the excavation area diffusing into the air.

  20. Lunar Excavator Validation Project (United States)

    National Aeronautics and Space Administration — Energid Technologies proposes to create a tool for simulation-based verification of lunar excavator designs. Energid will combine the best of 1) automatic control...

  1. Virtual taphonomy: A new method integrating excavation and postprocessing in an archaeological context. (United States)

    Wilhelmson, Helene; Dell'Unto, Nicoló


    The objective of this paper was to integrate excavation and post-processing of archaeological and osteological contexts and material to enhance the interpretation of these with specific focus on the taphonomical aspects. A method was designed, Virtual Taphonomy, based on the use and integration of image-based 3D modeling techniques into a 3D GIS platform, and tested on a case study. Merging the 3D models and a database directly in the same virtual environment allowed the authors to fully integrate excavation and post-processing in a complex spatial analysis reconnecting contexts excavated on different occasions in the field process. The case study further demonstrated that the method enabled a deeper understanding of the taphonomic agents at work and allowed the construction of a more detailed interpretation of the skeletal remains than possible with more traditional methods. The method also proved to add transparency to the entire research process from field to post-processing and interpretation. Other benefits were the timesaving aspects in documentation, not only in the excavation process but also in post-processing without creating additional costs in material, as the equipment used is available in most archaeological excavations. The authors conclude that this methodology could be employed on a variety of investigations from archaeological to forensic contexts and add significant value in many different respects (for example, detail, objectivity, complexity, time-efficiency) compared to methods currently used. © 2015 Wiley Periodicals, Inc.

  2. Tomographic and angiographic characteristics of eyes with macular focal choroidal excavation. (United States)

    Obata, Ryo; Takahashi, Hidenori; Ueta, Takashi; Yuda, Kentaro; Kure, Kayo; Yanagi, Yasuo


    To describe detailed clinical features of eyes with focal choroidal excavation. Twenty-one eyes of 17 patients with focal choroidal excavation were retrospectively studied. All eyes underwent thorough examination including funduscopy, visual field analysis, fundus autofluorescence imaging, fluorescein angiography, indocyanine green angiography, and B-scan ultrasonography. Patients' age ranged between 25 years and 70 years. Four patients (24%) were affected bilaterally. Spherical equivalent of refractive error ranged from 0.5 diopters to -10.0 diopters (D). Funduscopic examination showed hypopigmentation (n = 12) and yellowish plaquelike appearances (n = 2). Indocyanine green angiography showed not only filling defects at the excavation (n = 16) but also choroidal vascular hyperpermeability (n = 7) and punctate hyperfluorescent spots (n = 7). Cicatrized subretinal neovascularization was seen in three eyes. The mean follow-up period was 37 months (6-66 months). There was no change in the appearance of excavation. Central serous chorioretinopathy (n = 1) and choroidal neovascularization (n = 1) developed during follow-up. Background factors and ophthalmic findings are similar to those that have been reported previously, including relatively stable findings even after a long observation and the occurrence of central serous chorioretinopathy and choroidal neovascularization. Bilateral cases are not rare in the current cohort, and choroidal vascular hyperpermeability is frequently observed in indocyanine green angiography, suggesting there were choroidal hemodynamic changes around the excavation.

  3. In Appreciation of Claude Warren and Susan Rose's "William Pengelly's Techniques of Archaeological Excavation"

    Directory of Open Access Journals (Sweden)

    David L. Browman


    Full Text Available The short (40 pages pamphlet by Warren and Rose (1994 provides the answer to a complex question regarding credit for an important archaeological methodology, stratigraphic excavation. Let me set the stage for this appreciation. Continuing research on the beginnings of stratigraphic excavations in North America (Browman and Givens 1996, I sought the origins of the idea of actually excavating by strata, rather than post-facto interpretation, seen in North American as early as 1895 in the work of Henry Chapman Mercer, but not really introduced into the repertoire of American techniques until the work of Gamio, Kidder and Nelson between 1911 and 1914. The roots of the latter three seemed to lie with individuals such as Reisner, Boas, Uhle, who in turn seemed to rely on Hugo Obennaier, Gabriel de Mortillet, Marcellin Boule, and perhaps Pitt-Rivers, while Mercer's work could be traced to Boule and Albert Gaudry. Doggedly following back the roots, I found that Chapman (1989 could make a reasonable case that Pitt-Rivers had actually learned of the idea of strati­graphic excavation from Evans, Prestwich, and Lubbock, from the British scientists working with the Upper and Middle Paleolithic excavations during 1858-1868.

  4. Light induced fluorescence evaluation: A novel concept for caries diagnosis and excavation. (United States)

    Gugnani, Neeraj; Pandit, Ik; Srivastava, Nikhil; Gupta, Monika; Gugnani, Shalini


    In the era of minimal invasive dentistry, every effort should be directed to preserve the maximum tooth structure during cavity preparation. However, while making cavities, clinicians usually get indecisive at what point caries excavation should be stopped, so as to involve only the infected dentin. Apparent lack of valid clinical markers, difficulties with the use of caries detector dyes and chemo mechanical caries removal systems carve out a need for an improved system, which would be helpful to differentiate between the healthy and infected dentin during caries excavation. Light induced fluorescence evaluation is a novel concept implicated for caries detection and for making decisions while cavity preparation. This paper describes a few cases that explain the clinical applicability of this concept, using the SoproLife camera that works on this principle. Autofluorescence masking effect was found to be helpful for caries detection and the red fluorescence in the treatment mode was found helpful in deciding 'when to stop the excavation process.' Light induced fluorescence evaluation - Diagnosis - Treatment concept concept can be used as a guide for caries detection and excavation. It also facilitates decision making for stopping the caries excavation so as to involve infected dentin only.

  5. Finite element simulation of shallow-buried and mining tunnelling in adjacent frame structures

    Directory of Open Access Journals (Sweden)

    Chun-lai Chen


    Full Text Available By using three dimensional software MIDAS/GTS, the interactions among structures-soil-tunnel system is considered in this paper, and the working condition of shallow-buried underground excavation is simulated in the foundation of frame structures with the short-pile. The loadings and deformations of structures are studied before and after the tunnelling, and the influences of the following factors, including the horizontal position of tunnel and building, the height of building and the soil property, are analyzed. It is indicated that when the horizontal distance L equals zero (the distance between building axis to the tunnel axis, the building settlement increases gradually and shows a normal distribution during and after the tunnelling. Due to the small stiffness of frame structures with short-pile foundations, the building has large nonuniform settlement. When the distance of excavation is no less than 1.8 times of the thickness of overburden soil, the building settlement becomes stable, and the first principal stress P1 and maximum deformation rate E1 generally show a trend of decrease. With the increasing L, P1 and E1 will decrease accordingly, and the buildings tend to be inclined toward the tunnel. For a relatively larger distance, the building is nearly not affected.

  6. Very high precision survey equipment for great distances Surface surveys used to map out the surface network and the tunnelling machines then gyroscopically steered underground.

    CERN Multimedia


    At the beginning of the 1980s, CERN embarked on the enormous Large Electron-Positron Collider construction project. The excavation of the 27-kilometre LEP tunnel was a huge technical challenge. The tunnel-boring machines excavated the tunnel in 3.3 km octants and had to be operated with extraordinary precision to ensure that they reached their destination - the bottom of the next vertical shaft - precisely on target. The tunnel was excavated before high-performance instruments were developed for the construction of the Channel Tunnel. As no firms were willing to perform the surveying work, CERN's own surveyors, with experience from the SPS behind them, took up the challenge. At the surface, the surveyors established the world's most accurate geodetic network, performing measurements to an accuracy of 10-7, or 1mm per 10 km, using the Terrameter (see photo). The excavation of the tunnel was completed in 1988 and the finished tunnel's trajectory was found to diverge from the theoretical value specified by the p...

  7. Toxic hazards of underground excavation

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.; Chitnis, V.; Damasian, M.; Lemm, M.; Popplesdorf, N.; Ryan, T.; Saban, C.; Cohen, J.; Smith, C.; Ciminesi, F.


    Inadvertent intrusion into natural or man-made toxic or hazardous material deposits as a consequence of activities such as mining, excavation or tunnelling has resulted in numerous deaths and injuries in this country. This study is a preliminary investigation to identify and document instances of such fatal or injurious intrusion. An objective is to provide useful insights and information related to potential hazards due to future intrusion into underground radioactive-waste-disposal facilities. The methodology used in this study includes literature review and correspondence with appropriate government agencies and organizations. Key categories of intrusion hazards are asphyxiation, methane, hydrogen sulfide, silica and asbestos, naturally occurring radionuclides, and various mine or waste dump related hazards.

  8. Comparison of ISRU Excavation System Model Blade Force Methodology and Experimental Results (United States)

    Gallo, Christopher A.; Wilkinson, R. Allen; Mueller, Robert P.; Schuler, Jason M.; Nick, Andrew J.


    An Excavation System Model has been written to simulate the collection and transportation of regolith on the Moon. The calculations in this model include an estimation of the forces on the digging tool as a result of excavation into the regolith. Verification testing has been performed and the forces recorded from this testing were compared to the calculated theoretical data. A prototype lunar vehicle built at the NASA Johnson Space Center (JSC) was tested with a bulldozer type blade developed at the NASA Kennedy Space Center (KSC) attached to the front. This is the initial correlation of actual field test data to the blade forces calculated by the Excavation System Model and the test data followed similar trends with the predicted values. This testing occurred in soils developed at the NASA Glenn Research Center (GRC) which are a mixture of different types of sands and whose soil properties have been well characterized. Three separate analytical models are compared to the test data.

  9. Performance Evaluation of Bucket based Excavating, Loading and Transport (BELT) Equipment - An OEE Approach (United States)

    Mohammadi, Mousa; Rai, Piyush; Gupta, Suprakash


    Overall Equipment Effectiveness (OEE) has been used since last over two decades as a measure of performance in manufacturing industries. Unfortunately, enough, application of OEE in mining and excavation industry has not been duly adopted. In this paper an effort has been made to identify the OEE for performance evaluation of Bucket based Excavating, Loading and Transport (BELT) equipment. The conceptual model of OEE, as used in the manufacturing industries, has been revised to adapt to the BELT equipment. The revised and adapted model considered the operational time, speed and bucket capacity utilization losses as the key OEE components for evaluating the performance of BELT equipment. To illustrate the efficacy of the devised model on real-time basis, a case study was undertaken on the biggest single bucket excavating equipment - the dragline, in a large surface coal mine. One-year data was collected in order to evaluate the proposed OEE model.

  10. Clinical and spectral-domain optical coherence tomography findings in patients with focal choroidal excavation. (United States)

    Lee, Christopher Seungkyu; Woo, Se Joon; Kim, Yong-Kyu; Hwang, Duck Jin; Kang, Hae Min; Kim, Hyesun; Lee, Sung Chul


    To describe the clinical and spectral-domain optical coherence tomography (SD-OCT) findings in patients with focal choroidal excavation (FCE). Retrospective case series. Forty-one eyes of 38 patients with FCE identified in 2 tertiary medical centers in Korea. Clinical features, SD-OCT findings, and associated macular disorders of FCE were analyzed and detailed. Statistical associations among clinical features, including lesion type, size, and choroidal thickness, and frequency of association with central serous chorioretinopathy (CSC), choroidal neovascularization (CNV), and polypoidal choroidal vasculopathy (PCV). Mean patient age was 50.1 years (range, 25-76 years). The mean spherical equivalent of refractive error was -3.7 diopters (range, -10.0 to +1.5 diopters). Three patients (8%) had bilateral lesions, and 1 patient (3%) had 2 distinct lesions in the same eye. The mean FCE width and depth were 757 μm and 107 μm, respectively, with a positive correlation between width and depth (P = 0.003). The mean subfoveal choroidal thickness of FCE eyes was 284 μm, which was not statistically different from that of age-, sex-, and refractive error-matched normal subjects. Choroidal thickness in FCE was less in eyes with hyperreflective choroidal tissue under the excavation that was present in 22 eyes (54%) versus eyes without excavation (128 vs. 190 μm, respectively; P = 0.009). Twelve FCEs (29%) were the nonconforming type, revealing separation between the photoreceptor tips and the retinal pigment epithelium on SD-OCT. Nonconforming FCE was associated with visual symptoms (P excavation, and the excavated area in 1 eye with PCV enlarged slightly during follow-up. Focal choroidal excavation is a relatively common entity and frequently associated with choroidal diseases, including CSC, CNV, and PCV. Although FCE is classically thought to be a congenital malformation, acquired FCE forms possibly exist. Copyright © 2014 American Academy of Ophthalmology. Published by

  11. A Comparison Between The NORCAT Rover Test Results and the ISRU Excavation System Model Predictions Results (United States)

    Gallo, Christopher A.; Agui, Juan H.; Creager, Colin M.; Oravec, Heather A.


    An Excavation System Model has been written to simulate the collection and transportation of regolith on the moon. The calculations in this model include an estimation of the forces on the digging tool as a result of excavation into the regolith. Verification testing has been performed and the forces recorded from this testing were compared to the calculated theoretical data. The Northern Centre for Advanced Technology Inc. rovers were tested at the NASA Glenn Research Center Simulated Lunar Operations facility. This testing was in support of the In-Situ Resource Utilization program Innovative Partnership Program. Testing occurred in soils developed at the Glenn Research Center which are a mixture of different types of sands and whose soil properties have been well characterized. This testing is part of an ongoing correlation of actual field test data to the blade forces calculated by the Excavation System Model. The results from this series of tests compared reasonably with the predicted values from the code.

  12. National Advanced Drilling and Excavation Technologies Institute. Status report, March 1997

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, C.


    The National Advanced Drilling and Excavation Technologies (NADET) program is intended to pool support, talent, and technologies of the industries dependent upon drilling and excavation technologies to initiate, coordinate, and sustain programs capable of developing substantial technological advances. The NADET Institute has been funded by the DOE Office of Geothermal Technologies and is now supporting seven projects aimed at advanced geothermal drilling technologies. The Institute seeks to broaden its base of funding and technological support from both government and industry sources. Encouraging progress has been made with the support of dues-paying industrial members and industrial sponsorship of a substantial drilling research study.

  13. Stepwise Excavation Allows Apexogenesis in Permanent Molars with Deep Carious Lesions and Incomplete Root Formation. (United States)

    Hernandéz-Gatón, Patrícia; Serrano, César Ruiz; Nelson Filho, Paulo; De Castañeda, Esther Ruiz; Lucisano, Marília P; Silva, Raquel A B da; Silva, Léa A B da


    This study evaluated the stepwise excavation technique in 138 permanent molars with deep carious lesions and incomplete root formation within a 24-month clinical and radiographic follow-up period. In 96.7% of the cases, success was observed (no pain, integrity of restoration margins, absence of radiographic alterations and apexogenesis). The cases of failure (3.3%) were due to the loss of the temporary restoration. In conclusion, the stepwise excavation is a promising technique for permanent teeth with deep carious lesions and incomplete root formation as a minimally invasive approach because it allows the preservation of pulp vitality and occurrence of apexogenesis. © 2015 S. Karger AG, Basel.

  14. Long-term tunnel behaviour and ground movements after tunnelling in clayey soils

    Directory of Open Access Journals (Sweden)

    Kenichi Soga


    Full Text Available Long term ground movements above a tunnel may continue to increase with time after tunnelling in clayey soils as the tunnelling-induced excess pore water pressures dissipate, whilst the changing earth pressure acting on the tunnel leads to further tunnel deformation during consolidation. Furthermore the tunnel itself introduces new drainage conditions; that is, depending on the drainage condition of the tunnel lining, the effective stresses around the tunnel change with time, inducing further soil consolidation. A seepage rate from low permeability clayey soil is often very small and the groundwater seeping into the tunnel can evaporate quickly. Although a tunnel may look impermeable because the surface looks dry, it is possible that the tunnel drainage conditions are actually permeable. This paper summarises the investigation of soil-tunnel consolidation interaction, particularly focusing on ground surface movements and tunnel lining deformation in the interest of engineering concerns. Analysis results show that tunnel lining permittivity relative to the permeability of the surrounding ground plays an important role on both long-term ground movements as well as tunnel lining behaviour. The findings published in literature are reviewed step by step starting from a single tunnel, twin tunnels to complex cross passage structures. The mechanisms of tunnelling-induced soil consolidation for these structures are identified and, where applicable, possible engineering methodologies to assess the magnitude of long-term ground surface settlements and tunnel lining loads are proposed.

  15. 18 CFR 1304.303 - Channel excavation. (United States)


    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Channel excavation... Activities on TVA Flowage Easement Shoreland § 1304.303 Channel excavation. (a) Channel excavation of... encourage owners of flowage easement property to adopt the standards for channel excavation applicable to...

  16. Rock Properties Determined Continuously from TBM Excavation Process

    Directory of Open Access Journals (Sweden)

    Edita Lazarová


    Full Text Available The computer monitoring system used at excavation of exploratory galleries of motorway tunnels Branisko and Višòové-Dubná skala (excavated by Wirth TB-II-330H/M and Voest Alpine ATB 35H, respectively brought an ample study material. Several characteristics of rock environment in the line of exploratory galleries were determined using developed mathematical models. The verification of the models was carried out based on the comparison of results of mathematical models with results of common procedures of detailed engineering-geological investigation. The description of the continuous method and the results of comparisons are subject of this paper.

  17. Improved Concrete Cutting and Excavation Capabilities for Crater Repair Phase 2 (United States)


    than the goal of 1 ft/min. The SW60 wheel saw was the only option tested for saw cutting 24-in.-thick PCC to full depth. • The Volvo EW180D...excavator with the Volvo HB1400 moil point hammer was the most efficient technology for breaking up the 18- and 24-in.-thick PCC and required far less...time than the goal of 16 min per repair slab. The Volvo EW180D excavator with the Volvo HB1400 chisel point hammer was also capable of requiring less

  18. The Li(f)e of the Self: Missing Persons and Auto/Archeological Excavations (United States)

    Burdick, Jake


    This article describes and enacts a process of autobiographical inquiry, auto/archeology, which seeks to address problematic confluences of memory and identity in reconstructing one's historical narrative. Drawing on curriculum theory and Lacanian psychoanalysis, the author describes a process of excavation in which understandings of a prior…

  19. Improved Concrete Cutting and Excavation Capabilities for Crater Repair, Phase 1 (United States)


    required manpower, using Caterpillar SW45 and Sw60 wheel saws and Caterpillar and Volvo excavators, respectively, in 18-in.-thick PCC pavement did not...15 3.3 Husqvarna FS 6600D walk-behind saw ..................................................................... 17 3.4 Volvo ...FS 6600D. .............................................................................................................. 18 Figure 13. Volvo EW180D

  20. Content Literacy for the 21st Century: Excavation, Elevation, and Relational Cosmopolitanism in the Classroom (United States)

    Damico, James S.; Baildon, Mark


    This article makes the a case for conceptualizing content literacy, especially in social studies, as inquiry-based social practices for understanding and addressing complex, multifaceted problems. Two core practices especially needed for a Web-dominated 21st century are then described--excavation and elevation. Next, these two practices are…

  1. National advanced drilling and excavation technologies program: Summary of third meeting of interested Federal agencies

    Energy Technology Data Exchange (ETDEWEB)



    The purpose of the meeting was: (1) to discuss a proposal by the Massachusetts Institute of Technology (MIT) outlining a National Advanced Drilling and Excavation Technologies Program, (2) to brief participants on events since the last meeting, and (3) to hear about drilling research activities funded by the Department of Energy. The meeting agenda is included as Attachment B.

  2. Quarry Creek - Excavation, Analysis and Prospect of a Kansas City Hopewell Site, Fort Leavenworth, Kansas (United States)


    material, other than some debitage, burned earth and hearthstone debris, was associated with the burned wood on which this date was obtained, excavation of...throughout northeastern Kansas in uplands and valleys as glacial detritus. In addition to serving as hearthstones , they were used in a variety of

  3. The Freeze-Drying of Wet and Waterlogged Materials from Archaeological Excavations (United States)

    Watson, Jacqui


    Large quantities of wood and leather have been found in the waterlogged layers on archaeological excavations. Centuries of burial, however, have left these materials in a very degraded and vulnerable state such that if they dry out they will fall apart. This paper discusses the physics behind the freeze-drying techniques that allow the…

  4. Lightweight Bulldozer Attachment for Construction and Excavation on the Lunar Surface (United States)

    Mueller, Robert; Wilkinson, R. Allen; Gallo, Christopher A.; Nick, Andrew J.; Schuler, Jason M.; King, Robert H.


    A lightweight bulldozer blade prototype has been designed and built to be used as an excavation implement in conjunction with the NASA Chariot lunar mobility platform prototype. The combined system was then used in a variety of field tests in order to characterize structural loads, excavation performance and learn about the operational behavior of lunar excavation in geotechnical lunar simulants. The purpose of this effort was to evaluate the feasibility of lunar excavation for site preparation at a planned NASA lunar outpost. Once the feasibility has been determined then the technology will become available as a candidate element in the NASA Lunar Surface Systems Architecture. In addition to NASA experimental testing of the LANCE blade, NASA engineers completed analytical work on the expected draft forces using classical soil mechanics methods. The Colorado School of Mines (CSM) team utilized finite element analysis (FEA) to study the interaction between the cutting edge of the LANCE blade and the surface of soil. FEA was also used to examine various load cases and their effect on the lightweight structure of the LANCE blade. Overall it has been determined that a lunar bulldozer blade is a viable technology for lunar outpost site preparation, but further work is required to characterize the behavior in 1/6th G and actual lunar regolith in a vacuum lunar environment.

  5. Myelinated nerve fiber-associated local scleral excavation and induced axial myopia. (United States)

    Oh, Baek-Lok; Hwang, Jeong-Min; Woo, Se Joon


    To investigate the association between the distributions of local scleral excavation and myelinated nerve fibers (MNF) and to elucidate the pathogenic mechanism of axial myopia in eyes with MNF. In six eyes of six pediatric patients with MNF, the distribution of the MNF on fundus photography was compared with the regional excavation of the sclera on linear scans across the fovea and a peripapillary circular scan of spectral domain optical coherence tomography. The tilting of Bruch membrane on vertical scan of spectral domain optical coherence tomography was associated with the major distribution of MNF (κ = 1, Cohen's kappa coefficient). The area of MNF of 12 clock-hour segments and focal scleral excavation on circular scan of spectral domain optical coherence tomography were significantly correlated (P excavation was strongly associated with the distribution of the MNF. This result indicates that the retinal areas deprived of visual stimulation by the MNF contribute to the development of axial myopia through local effects on the underlying sclera in early life.

  6. Safety excavation; Seguranca em escavacoes

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Walter Manoel [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)


    In the construction and maintenance services of buried pipelines, the excavation is the activity that contains larger risk, could cause serious accidents. Norms, procedures and technical articles, national and international goods, should be followed for legal and technical aspects. This paper - Safety in Excavations - has purpose to gather all the technical concepts and of safety in a document denominated Procedure of Safety Excavation, serving as instrument to systematize and control the execution of excavation services in construction civil, assembly and pipelines repairs, seeking the people, facilities and the environment's safety. (author)

  7. Railway tunnels in Europe and North America (United States)


    This list of railway tunnels (longer than 1, 000 m) was compiled by the secretariat from various national and international sources. The list is intended to serve as a reference inventory for a long railway tunnels in Europe and North America. Tunnel...

  8. Aeronautical Wind Tunnels, Europe and Asia (United States)


    site: February 2006 Page 117 of 308 European and Asian Wind Tunnels KAIST Anechoic Wind Tunnel, Korea Advanced... KAIST Anechoic Wind Tunnel.” <> Korea Advanced Institute of Science and Technology. “Low Turbulence Open

  9. A low-cost approach for the documentation and monitoring of an archaeological excavation site (United States)

    Hoffmeister, Dirk; Orrin, Joel; Richter, Jürgen


    The documentation of archaeological excavations and in particular a constant monitoring is often time-consuming and depending on humańs capabilities. Thus, remote sensing methods, which allow an objective reproduction of the current state of an excavation and additional information are of interest. Therefore, a low-cost approach was tested on an open-air excavation site for two days in September 2015. The Magdalenian excavation site of Bad Kösen-Lengefeld, Germany is one important site in a system of about 100 sites in the area of the small rivers Saale and Unstrut. The whole site and the surrounding area (200 by 200 m) was first observed by a GoPro Hero 3+ mounted on a DJI-Phantom 2 UAV. Ground control points were set-up in a regular grid covering the whole area. The achieved accuracy is 20 mm with a ground resolution of 45 mm. As a test, the GoPro Hero 3+ camera was additionally mounted on a small, extendable pole. With this second low-cost, easy to apply monitoring approach, pictures were automatically taken every second in a stop-and-go mode. In order to capture the excavation pit (7 by 4 m), two different angles were used for holding the pole, which focused on the middle and on the border of the pit. This procedure was repeated on the following day in order to document the excavation process. For the registration of the images, the already existing and measured excavation nails were used, which are equally distributed over the whole site in a 1 m grid. Thus, a high accurate registration of the images was possible (>10 mm). In order to approve the accuracy of the already derived data, the whole site was also observed by a Faro Focus 3D LS 120 laser scanner. The measurements of this device were registered by spherical targets, which were measured in the same reference system. The accuracy of the registration and the ground resolution for the image based approach for both days was about 4 mm. From these two measurements the process of the excavation was easily

  10. Mobile continuous lunar excavation (United States)

    Paterson, John L.


    A novel approach to the concept of lunar mining and the use of in situ oxygen, metallics, and ceramics is presented. The EVA time required to set up, relocate, and maintain equipment, as well as the cost per pound of shipping the mining and processing equipment to the moon are considered. The proposed soil fracturing/loading mechanisms are all based loosely on using the Apollo Lunar Roving Vehicle (LRV) Frame. All use motor driven tracks for mobility in the forward/reverse and left/right direction. All mechanisms employ the concept of rototillers which are attached to a gantry which, through the use of motor-driven lead screws, provide the rototillers with an up/down capability. A self-reactant excavator, a local mass enhanced excavator, and a soil reactant excavator are illustrated.

  11. Lunar Regolith Excavation Competition (United States)

    Liles, Cassandra


    The Lunar Regolith Excavation Competition is a new competition that needs graphics, logos, rules, as well as an arena. Although this is the first year of the competition, the competition is modeled after an existing competition, the Centennial Lunar Excavator Challenge. This competition however is aimed at college students. This makes the challenge identifying key aspects of the original competition and modeling them to fit into an easier task, and creating exciting advertisement that helps encourage participation. By using a youth focus group, young insight, as well as guiding advice from experts in the field, hopefully an arena can be designed and built, rules can be molded and created to fit, and alluring graphics can be printed to bring about a successful first year of the Lunar Regolith Excavation Competition.

  12. Analysis of tectonic structures and excavation induced fractures in the Opalinus Clay, Mont Terri underground rock laboratory (Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Nussbaum, Ch.; Bossart, P. [Federal Office of Topography swisstopo, Wabern (Switzerland); Amann, F. [Swiss Federal Institute of Technology Zuerich, Zuerich (Switzerland); Aubourg, Ch. [Laboratoire des fluides complexes et leurs reservoirs, Centre National de la Recherche Scientitfique CNRS, Universite de Pau, Pau (France)


    Excavated in the Opalinus Clay formation, the Mont Terri underground rock laboratory in the Jura Mountains of NW Switzerland is an important international test site for researching argillaceous formations, particularly in the context of deep geological disposal of radioactive waste. The rock laboratory is intersected by naturally formed tectonic structures, as well as artificial fractures primarily formed as a consequence of tunnel excavation and the associated stress redistribution. The description and characterisation of tectonic and artificial structures is, in many cases, of key importance for interpreting the results of the various in situ experiments conducted in the rock laboratory. Systematic small-scale mapping of the tunnel walls and floor, and adjacent niches, provides basic information about the geometry and the kinematics of the geological fractures intersecting the underground laboratory. A compilation of all tectonic structures identified is presented in this paper. The underground laboratory is located in the backlimb of the Mont Terri anticline, a NNW-vergent imbricate fault-bend fold, which is characterised by a pronounced along-strike asymmetry resulting from variously oriented inherited faults. The total shortening accommodated by this structure was estimated by mass (area) balancing to be approximately 2.1 km. The Mont Terri area is significantly affected by N- to NNE-striking normal faults of the Eo-Oligocene Rhine-Bresse transfer zone and by ENE-striking faults of Late Variscan age. Depending on their orientation with respect to the transport direction towards the NNW, these faults served as oblique and frontal ramps during the subsequent Jura thrusting in the Late Miocene. The various fault systems identified in the underground rock laboratory clearly correlate with the regional-scale structures. In addition to classical structural analysis, the anisotropy of magnetic susceptibility was measured to determine the magnetic fabric and strain

  13. Laboratory Study of the Influence of Substrate Type and Temperature on the Exploratory Tunneling by Formosan Subterranean Termite

    Directory of Open Access Journals (Sweden)

    Bal K. Gautam


    Full Text Available Using two-dimensional foraging arenas, laboratory tests were conducted to investigate the effect of soil type, soil moisture level and ambient temperature on the exploratory tunneling by Coptotermes formosanus Shiraki. In choice arenas consisting of two substrate types having two moisture levels each, and conducted at a constant temperature of 22 °C, a significantly greater proportion of termites aggregated in sand than in sandy loam. Similarly, the length of excavated tunnels was also increased in sand. In a given substrate, termite aggregation or tunnel length did not differ between 5% and 15% moisture levels. In no-choice tests, where three different substrates (sand, sandy loam and silt loam were tested at two temperatures (22 °C and 28 °C, excavations were significantly greater in sand than either sandy loam or silt loam at 22 °C. Fewer primary tunnels were constructed in sandy loam than in sand and fewer branched tunnels than either in sand or silt loam. No significant difference in either tunnel length or number of primary or branched tunnels was found between these two temperatures.

  14. Tunneling Flight Time, Chemistry, and Special Relativity. (United States)

    Petersen, Jakob; Pollak, Eli


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

  15. Hydrogeochemical and microbiological effects on fractures in the Excavation Damaged Zone (EDZ)

    Energy Technology Data Exchange (ETDEWEB)

    Laaksoharju, Marcus (Geopoint AB, Sollentuna (Sweden)); Gimeno, Maria; Auque, Luis F.; Gomez, Javier B.; Acero, Patricia (Univ. of Zaragoza, Earth Science Dept., Zaragoza (Spain)); Pedersen, Karsten (Microbial Analytics, Moelnlycke (Sweden))


    Due to the disturbances associated with the excavation, construction and closure of the repository for storage of spent nuclear fuel, the saturation state of the groundwaters at repository depth with respect to several mineral phases may change and mineral precipitation/dissolution reactions may take place. In addition, changing groundwater conditions may facilitate microbial growth on fracture walls. These processes are of importance since they may influence the stability and safety of the Excavation Damaged Zone (EDZ) because precipitation and microbial growth may seal the hydraulically conductive fractures caused by the repository construction. Different processes expected to occur in the EDZ during the open repository conditions and after repository closure have been evaluated based on data from Forsmark, Laxemar and Aespoe. Geochemical modelling by using PHREEQC was applied to simulate the following cases: - increase of temperature to 50 deg C and 100 deg C to simulate the thermal effects from spent nuclear fuel; - open repository conditions simulating atmospheric conditions (equilibrium with atmospheric partial pressures of CO{sub 2}(g) and O{sub 2}(g)); - mixing with deep saline water simulating up-coning; - mixing with shallow infiltration waters simulating down-coning; - mixing with different proportions of cement dissolution porewater. The effect of variable temperatures (up to 100 deg C) on most of the above modelled processes has also been assessed. A preliminary estimation of the effect of mineral precipitation on the hydraulic conductivity of the EDZ has been carried out. For most of the modelling cases, the estimated decrease of the hydraulic conductivity in ten years is smaller than 2%. Microbial evaluation was used to identify the potential for microbial calcite and iron hydroxide formation during various repository conditions. The most important groundwater parameters for microorganisms, are pH and carbonate, ferrous iron, methane and the

  16. Dissipative Effect and Tunneling Time

    Directory of Open Access Journals (Sweden)

    Samyadeb Bhattacharya


    Full Text Available The quantum Langevin equation has been studied for dissipative system using the approach of Ford et al. Here, we have considered the inverted harmonic oscillator potential and calculated the effect of dissipation on tunneling time, group delay, and the self-interference term. A critical value of the friction coefficient has been determined for which the self-interference term vanishes. This approach sheds new light on understanding the ion transport at nanoscale.

  17. Archaeological Excavation Report for Proposed Well 199-K-131 in Support of the 100-KR-4 Pump-and-Treat Project

    Energy Technology Data Exchange (ETDEWEB)

    Woody, Dave M.; Prendergast-Kennedy, Ellen L.


    An archaeological excavation was conducted at the site of proposed groundwater monitoring well 199-K-131 in support of the 100-KR-4 Pump-and-Treat Project between June 2 and 3, 2004. Excavations confirmed that there were no intact cultural deposits at the proposed well location. This report was prepared to document the findings of the test excavation.

  18. Regolith Advanced Surface Systems Operations Robot (RASSOR) Phase 2 and Smart Autonomous Sand-Swimming Excavator (United States)

    Sandy, Michael


    The Regolith Advanced Surface Systems Operations Robot (RASSOR) Phase 2 is an excavation robot for mining regolith on a planet like Mars. The robot is programmed using the Robotic Operating System (ROS) and it also uses a physical simulation program called Gazebo. This internship focused on various functions of the program in order to make it a more professional and efficient robot. During the internship another project called the Smart Autonomous Sand-Swimming Excavator was worked on. This is a robot that is designed to dig through sand and extract sample material. The intern worked on programming the Sand-Swimming robot, and designing the electrical system to power and control the robot.

  19. The 1978 and 1979 Excavations at Strawberry Island in the McNary Reservoir. (United States)


    paper for nearly two years. Lorna 4 . J vi Elliott and Dolores Lehn carried the report typing through the final draft stage. Gail Rowland...of pit feature structure is suggested, and the model’s potential application to excavation and inter - pretation of Plateau pit houses is discussed...communal semisubterranean structures, semisubterranean menstrual huts, hide-smoking pits, and lithic heat treatment pits. The prob- lem is that

  20. FOCAL CHOROIDAL EXCAVATION AND ITS ASSOCIATION WITH PACHYCHOROID SPECTRUM DISORDERS: A Review of the Literature and Multimodal Imaging Findings. (United States)

    Chung, Hyewon; Byeon, Suk Ho; Freund, K Bailey


    To review the literature regarding focal choroidal excavation and show its association with pachychoroid features through case examples. The clinical manifestations of focal choroidal excavation are illustrated with various imaging modalities inclusive of fundus photography, fundus autofluorescence, fluorescein angiography, indocyanine green angiography, spectral domain optical coherence tomography (OCT), enhanced depth imaging OCT, and swept-source OCT. Diffuse or focal areas of choroidal thickening with dilated choroidal vessels (pachyvessels) on OCT and choroidal hyperpermeability on indocyanine green angiography are present in many eyes with focal choroidal excavation. Clinical and imaging features of associated comorbidities including central serous chorioretinopathy and choroidal neovascularization are described. Focal choroidal excavation appears to be a manifestation of pachychoroid spectrum disease associated with choroidal thickening and pachyvessels on structural OCT and choroidal hyperpermeability on indocyanine green angiography.

  1. Remediation of PCB contaminated soils in the Canadian Arctic: excavation and surface PRB technology. (United States)

    Kalinovich, Indra; Rutter, Allison; Poland, John S; Cairns, Graham; Rowe, R Kerry


    The site BAF-5 is located on the summit of Resolution Island, Nunavut, just southeast of Baffin Island at 61 degrees 35'N and 60 degrees 40'W. The site was part of a North American military defense system established in the 1950s that became heavily contaminated with PCBs during and subsequent, its operational years. Remediation through excavation of the PCB contaminated soil at Resolution Island began in 1999 and at its completion in 2006 approximately 5 tonnes of pure PCBs in approximately 20,000 m3 of soil were remediated. Remediation strategies were based on both quantity of soil and level of contamination in the soil. Excavation removed 96% of the PCB contaminated soil on site. In 2003, a surface funnel-and-gate permeable reactive barrier was design and constructed to treat the remaining contamination left in rock crevices and inaccessible areas of the site. Excavation had destabilized contaminated soil in the area, enabling contaminant migration through erosion and runoff pathways. The barrier was designed to maximize sedimentation through settling ponds. This bulk removal enabled the treatment of highly contaminated fines and water through a permeable gate. The increased sediment loading during excavation required both modifications to the funnel and a shift to a more permeable, granular system. Granulated activated charcoal was chosen for its ability to both act as a particle retention filter and adsorptive filter. The reduction in mass of PCB and volume of soils trapped by the funnel of the barrier indicate that soils are re-stabilizing. In 2007, nonwoven geotextiles were re-introduced back into the filtration system as fine filtering could be achieved without clogging. Monitoring sites downstream indicate that the barrier system is effective. This paper describes the field progress of PCB remediation at Resolution Island.

  2. Tarrant Launceston: Survey and excavation of a long barrow with secondary burial at Race Down.


    Manley, H.P.; Evans, Damian; Hewitt, Iain; Phurphy, P.; Russell, Miles; Welham, Kate


    In March 2003, it was noted that rabbit burrowing had uncovered possible human remains close to the centre of Race Down long barrow. In order to determine whether the bones were human and/or of forensic interest, the School of Conservation Sciences (now the Department of Archaeology, Anthropology & Forensic Science), Bournemouth University, carried out a limited investigation on behalf of Dorset Police and the landowner, Defence Estates. The spoil heap of the rabbit burrow was excavated and t...

  3. Extreme cellular adaptations and cell differentiation required by a cyanobacterium for carbonate excavation. (United States)

    Guida, Brandon Scott; Garcia-Pichel, Ferran


    Some cyanobacteria, known as euendoliths, excavate and grow into calcium carbonates, with their activity leading to significant marine and terrestrial carbonate erosion and to deleterious effects on coral reef and bivalve ecology. Despite their environmental relevance, the mechanisms by which they can bore have remained elusive and paradoxical, in that, as oxygenic phototrophs, cyanobacteria tend to alkalinize their surroundings, which will encourage carbonate precipitation, not dissolution. Therefore, cyanobacteria must rely on unique adaptations to bore. Studies with the filamentous euendolith, Mastigocoleus testarum, indicated that excavation requires both cellular energy and transcellular calcium transport, mediated by P-type ATPases, but the cellular basis for this phenomenon remains obscure. We present evidence that excavation in M. testarum involves two unique cellular adaptations. Long-range calcium transport is based on active pumping at multiple cells along boring filaments, orchestrated by the preferential localization of calcium ATPases at one cell pole, in a ring pattern, facing the cross-walls, and by repeating this placement and polarity, a pattern that breaks at branching and apical cells. In addition, M. testarum differentiates specialized cells we call calcicytes, that which accumulate calcium at concentrations more than 500-fold those found in other cyanobacteria, concomitantly and drastically lowering photosynthetic pigments and enduring severe cytoplasmatic alkalinization. Calcicytes occur commonly, but not exclusively, in apical parts of the filaments distal to the excavation front. We suggest that calcicytes allow for fast calcium flow at low, nontoxic concentrations through undifferentiated cells by providing buffering storage for excess calcium before final excretion to the outside medium.

  4. Effect of Blast-Induced Vibration from New Railway Tunnel on Existing Adjacent Railway Tunnel in Xinjiang, China (United States)

    Liang, Qingguo; Li, Jie; Li, Dewu; Ou, Erfeng


    The vibrations of existing service tunnels induced by blast-excavation of adjacent tunnels have attracted much attention from both academics and engineers during recent decades in China. The blasting vibration velocity (BVV) is the most widely used controlling index for in situ monitoring and safety assessment of existing lining structures. Although numerous in situ tests and simulations had been carried out to investigate blast-induced vibrations of existing tunnels due to excavation of new tunnels (mostly by bench excavation method), research on the overall dynamical response of existing service tunnels in terms of not only BVV but also stress/strain seemed limited for new tunnels excavated by the full-section blasting method. In this paper, the impacts of blast-induced vibrations from a new tunnel on an existing railway tunnel in Xinjiang, China were comprehensively investigated by using laboratory tests, in situ monitoring and numerical simulations. The measured data from laboratory tests and in situ monitoring were used to determine the parameters needed for numerical simulations, and were compared with the calculated results. Based on the results from in situ monitoring and numerical simulations, which were consistent with each other, the original blasting design and corresponding parameters were adjusted to reduce the maximum BVV, which proved to be effective and safe. The effect of both the static stress before blasting vibrations and the dynamic stress induced by blasting on the total stresses in the existing tunnel lining is also discussed. The methods and related results presented could be applied in projects with similar ground and distance between old and new tunnels if the new tunnel is to be excavated by the full-section blasting method.

  5. Archaeological Geophysics, Excavation, and Ethnographic Approaches Toward a Deeper Understanding of an Eighteenth Century Wichita Site (United States)

    Carlock, Michael Don

    This research exemplifies a multidirectional approach to an archaeological interpretation of an eighteenth century Wichita village and fortification located on the Red River bordering Oklahoma and Texas. A battle that is believed to have occurred at the Longest site (34JF1) in 1759 between Spanish colonials and a confederation of Native Americans led to several Spanish primary documents describing the people that lived there, the fortification and surrounding village, and of course the battle itself. Investigation of the Longest site (34JF1) in Oklahoma presents a remarkable opportunity to combine extensive historical research, archaeological prospecting using geophysics, and traditional excavation techniques in order to gain a more complete understanding of this important archaeological site. The fortification at the Longest site, as well as possible associated structures and cultural features, were relocated using magnetometry, ground-penetrating radar, and electrical resistivity methods. Then, previously translated historical documents provided valuable insights in the interpretation of the geophysical data. Finally, archaeological excavation permitted validation of the interpretations and identification of features described in the historical accounts. As interpreted in the geophysical data and excavations, the construction of the fortification and associated interior subterranean rooms suggests that it is indeed the fortification involved in the altercation between the Taovayas and the Spanish in 1759.

  6. Focal choroidal excavation: a preliminary interpretation based on clinic and review. (United States)

    Liu, Guang-Hui; Lin, Bing; Sun, Xin-Quan; He, Zi-Fang; Li, Ji-Rong; Zhou, Rong; Liu, Xiao-Ling


    To describe the clinical and imaging characteristics associated with focal choroidal excavation (FCE), analyze the possible complication, and interpret its probable etiopathogenesis. Retrospective descriptive case series of 37 eyes of 32 patients with FCE. Findings of spectral-domain optical coherence tomography (SD-OCT), fluorescein angiography, indocyanine green angiography, and clinical features were analyzed. All patients were Chinese. Five patients (15.6%) were bilaterally involved. Patients' ages ranged from 7 to 66y. Refractive error ranged between +2.0 D and -11.0 D. Mean best-corrected visual acuity was 0.6 (range, 0.1 to 1.2). Fundus examinations exhibited mild-moderate localized pigmentary disturbances in the corresponding area of 17 eyes. Fluorescein angiography performed in 18 patients showed varying degrees of hyperfluorescence and hypofluorescence related to a range of retinal pigment epithelium (RPE) alterations. Indocyanine green angiography performed in 7 patients showed hypofluorescence at the excavation. SD-OCT demonstrated choroidal excavation in all 37 eyes. Twenty-nine eyes showed a single lesion of FCE, and three eyes showed 2-3 separated lesions. Fifteen eyes showed separation between the photoreceptor tips and RPE consistent with nonconforming FCE. Central serous chorioretinopathy (CSC, n=1) and choroidal neovascularization (CNV, n=1) developed during follow-up. FCE could be interpreted as congenital focal choroidal dysplasia involving the RPE, choriocapillaris, and photoreceptor associated with the faulty anatomy. The abnormal anatomy of FCE was similar to anatomy at risk of CSC and CNV.

  7. Excavation and aggregation as organizing factors in de novo construction by mound-building termites. (United States)

    Green, Ben; Bardunias, Paul; Turner, J Scott; Nagpal, Radhika; Werfel, Justin


    Termites construct complex mounds that are orders of magnitude larger than any individual and fulfil a variety of functional roles. Yet the processes through which these mounds are built, and by which the insects organize their efforts, remain poorly understood. The traditional understanding focuses on stigmergy, a form of indirect communication in which actions that change the environment provide cues that influence future work. Termite construction has long been thought to be organized via a putative 'cement pheromone': a chemical added to deposited soil that stimulates further deposition in the same area, thus creating a positive feedback loop whereby coherent structures are built up. To investigate the detailed mechanisms and behaviours through which termites self-organize the early stages of mound construction, we tracked the motion and behaviour of major workers from two Macrotermes species in experimental arenas. Rather than a construction process focused on accumulation of depositions, as models based on cement pheromone would suggest, our results indicated that the primary organizing mechanisms were based on excavation. Digging activity was focused on a small number of excavation sites, which in turn provided templates for soil deposition. This behaviour was mediated by a mechanism of aggregation, with termites being more likely to join in the work at an excavation site as the number of termites presently working at that site increased. Statistical analyses showed that this aggregation mechanism was a response to active digging, distinct from and unrelated to putative chemical cues that stimulate deposition. Agent-based simulations quantitatively supported the interpretation that the early stage of de novo construction is primarily organized by excavation and aggregation activity rather than by stigmergic deposition. © 2017 The Author(s).

  8. Low-energy Planetary Excavator (LPE) Project (United States)

    National Aeronautics and Space Administration — ORBITEC is developing an innovative Low-energy Planetary Excavator (LPE) to excavate in situ regolith, ice-regolith mixes, and a variety of other geologic materials...

  9. Low-energy Planetary Excavator (LPE) Project (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop an innovative Low-energy Planetary Excavator (LPE) to excavate in situ regolith, ice-regolith mixes, and a variety of other geologic...

  10. Quantum tunneling and field electron emission theories

    CERN Document Server

    Liang, Shi-Dong


    Quantum tunneling is an essential issue in quantum physics. Especially, the rapid development of nanotechnology in recent years promises a lot of applications in condensed matter physics, surface science and nanodevices, which are growing interests in fundamental issues, computational techniques and potential applications of quantum tunneling. The book involves two relevant topics. One is quantum tunneling theory in condensed matter physics, including the basic concepts and methods, especially for recent developments in mesoscopic physics and computational formulation. The second part is the f

  11. Deriner hydropower scheme : geotechnical issues and the particular case of the spillway tunnels design and construction

    Energy Technology Data Exchange (ETDEWEB)

    Cekerevac, C.; Wohnlich, A. [STUCKY SA, Remens (Switzerland)


    Geotechnical issues related to the construction of the Deriner dam and overflow spillways in Turkey were discussed in this paper. As the first phase in the Coruh River development plan, the dam will be one of the highest dams in the world with an annual production of 2300 GWh of electrical energy. Excavations for the dam were conducted in a highly fractured and weathered rock mass. Finite element analyses and structural discontinuity analyses were conducted to ensure the dam's future reliability. The rock mass was comprised of granodiorite intruded by diabase dykes. The upper layer of the rock was decompressed and heavily jointed. Unconfined compression tests were conducted to determine the strength of the intact rocks. Triaxial tests were conducted on rock cores in order to determine Mohr-Coulomb shear strength peak parameters. A joint survey was conducted to determine rock mechanical and joint shear strength properties. Two gated spillway tunnels were designed to evacuate floodwater, and static and dynamic in situ tests were conducted to estimate the deformability of the rock mass. The surrounding dam excavation was simulated using the finite element method. Standard rock mass classifications and rock wedge stability analyses were used to design tunnel supports. The design was successfully applied to the spillway excavation area. 10 refs., 5 tabs., 9 figs.

  12. Choice of rock excavation methods for the Swedish deep repository for spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Baeckblom, Goeran [Conrox, Stockholm (Sweden); Christiansson, Rolf [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Lagerstedt, Leif [SwedPower AB, Stockholm (Sweden)


    Choice of rock excavation methods will or may have implications for a number of issues like repository layout, long term and operational safety, environmental impact, design of and operation of transport vehicles and methodology for backfilling the repository before closure as well as effects on costs and schedules. To fully analyse the issues at hand related to selection of excavation methods, SKB organized a project with the objectives: To investigate and compare principal technical solutions for rock excavation, both methods that are used at present but also methods that may be feasible 10 years from now; To assess how the selection of excavation method influences the design and operation of the deep repository; To present a definition of the Excavation Damaged/Disturbed Zone and practical methods for measurements of EDZ; To present advantages and disadvantages with different excavation methods for the various tunnels and underground openings as a basis for selection of preferred excavation methods; To present the Design Justification Statement for the selection of particular excavation methods for the different tunnels and openings in the deep repository to underpin a decision on excavation method; and To present background data that may be required for the evaluation of the long term safety of the deep repository. Main alternatives studied are very smooth blasting, excavation with a tunnel-boring machine (TBM) and excavation with horizontal pull-reaming using more or less conventional raise-boring equipment. The detailed studies were carried through in co-operation with major suppliers and end-users of the technology. An observation in this study is that all excavation technologies are mature; no major breakthroughs are foreseen within a 10 year period but it is likely that for any technology selected, SKB would specifically fine-tune the design of the equipment and work procedures in view of requirements and site specific conditions. Excavation methods have

  13. Icy Regolith Excavation and Volatile Capture under Vacuum Conditions Project (United States)

    National Aeronautics and Space Administration — NASA Kennedy Space Center is developing a testbed for producing large volume mixtures of ice and regolith under low pressure inside a laboratory vacuum...

  14. Excavating obstacles and enablers to internationalization at home

    NARCIS (Netherlands)

    Beelen, Jos; Woldegiyorgis, Ayenachew A.; Rumbley, Laura E.; de Wit, Hans


    Gives an overview of my research as a visiting scholar at The Boston College Center for International Higher Education. This research classifies these obstacles and enablers in four categories: disciplinary, external, internal and personal.

  15. The Excavation and Remediation of the Sandia National Laboratories Chemical Waste Landfill

    Energy Technology Data Exchange (ETDEWEB)



    The Chemical Waste Landfill (CWL) at Sandia National Laboratories/New Mexico (SNL/NM) is a 1.9-acre disposal site that was used for the disposal of chemical wastes generated by many of SNL/NM research laboratories from 1962 until 1985. These laboratories were primarily involved in the design, research and development of non-nuclear components of nuclear weapons and the waste generated by these labs included small quantities of a wide assortment of chemical products. A Resource Conservation and Recovery Act (RCRA) Closure Plan for the Chemical Waste Landfill was approved by the New Mexico Environment Department (NMED) in 1992. Subsequent site characterization activities identified the presence of significant amounts of chromium in the soil as far as 80 feet below ground surface (fbgs) and the delineation of a solvent plume in the vadose zone that extends to groundwater approximately 500 fbgs. Trichloroethylene (TCE) was detected in some groundwater samples at concentrations slightly above the drinking water limit of 5 parts per billion. In 1997 an active vapor extraction system reduced the size of the TCE vapor plume and for the last six quarterly sampling events groundwater samples have not detected TCE above the drinking water standard. A source term removal, being conducted as a Voluntary Corrective Measure (VCM), began in September 1998 and is expected to take up to two years. Four distinct disposal areas were identified from historical data and the contents of disposal pits and trenches in these areas, in addition to much of the highly contaminated soil surrounding the disposal cells, are currently being excavated. Buried waste and debris are expected to extend to a depth of 12 to 15 fbgs. Excavation will focus on the removal of buried debris and contaminated soil in a sequential, area by area manner and will proceed to whatever depth is required in order to remove all pit contents. Up to 50,000 cubic yards of soil and debris will be removed and managed during

  16. Studies on the immature stages and burrow excavating behavior of ...

    African Journals Online (AJOL)

    Drury) were investigated in this study that was carried out between 2004 and 2007 in the left bank of River Indus Sindh province. The study showed that S. monstrosus which is a nocturnal and voracious carnivorous insect, passed through 9 ...

  17. Excavator-based processor operator productivity and cost analysis ...

    African Journals Online (AJOL)

    Operator impact on productivity and cost using similar processor machines was addressed in this case study. The study had two objectives: (1) determine the extent of operator productivity variation between six processor operators in a harvesting operation; and (2) determine potential cost implications associated with ...

  18. Excavations at Kanjetar and Kaj on the Saurashtra Coast, Gujarat

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A.S.; Sundaresh; Abhayan, G.S.; Joglekar, P.P.

    domestic and wild animals (Table 1). Except one crab (Scylla serrata) all other skeletal elements belong to mammals. The domestic mammals consist of cattle, buffalo, sheep/goat, dog and cat. The wild mammals identified were the nilgai and blackbuck.... Interestingly one bone could be identified to that of Genus Equus; but the species could not be securely identified. Six fragments of the domestic cat were recovered that belong to a single animal. There were no cut marks on all these fragments but all were...

  19. Green Remediation: Best Management Practices for Excavation and Surface Restoration (United States)

    This fact sheet is one of a series describing best management practices (BMPs) for green remediation, which holistically addresses a cleanup project's energy requirements, air emissions, impacts on water, impacts on land and ecosystems, material consumpt..

  20. Paleontological excavations in designated wilderness: theory and practic (United States)

    Christopher V. Barns


    Wilderness is widely recognized as a valuable environment for scientific research, and it is generally assumed that this research will benefit the wilderness resource. But what if the research is of value only in understanding an ecosystem that has been extinct for 65 million years? What if thousands of pounds of material must be removed from the wilderness to conduct...

  1. Corrosion and coating defects on buried pipelines under CP: Excavations data collection and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Karcher, Sebastien; Campaignolle, Xavier; Masson, Bernard; Meyer, Michel [Gaz de France Research and Development Division, 361 avenue du President Wilson, BP33 93211 Saint Denis La Plaine (France)


    Onshore gas transmission pipelines are conjointly protected against external corrosion by an organic coating and by cathodic protection (CP). Owing to particular defects or coating aging in the long term in ground, the protective efficiency of this dual system may be impaired. Consequently, external corrosion may develop and, eventually, threaten the integrity of the line if not detected and mitigated in time. To ensure continued protection of its lines against external corrosion, Gaz de France carries out, routinely, several maintenance and monitoring activities on the CP system. In addition, above ground surveys allow a better assessment of possible coating faults. However, it is necessary to continuously improve the reliability of the corrosion prediction to optimize the maintenance of pipelines. When indications and measurements from any mean of inspection (in-line inspection or above ground surveys) lead to suspect the presence of any significant metal defect, an excavation of the concerned pipe section is performed. At each excavation location, many parameters are collected to document the existing conditions of coating and steel. If sufficiently extended and reliable, this information may help to understand the root causes for development of corrosion. Eventually, thorough analysis of field data resulting either from inspection or from maintenance operations could lead to corrosion prediction. Since the volume of these data is large, reliability and consistency of information is absolutely required. Gaz de France has implemented a systematic data collection procedure on excavation sites, together with data analysis through a range of treatment methods. Data on more than 1400 excavations, pertaining to a set of different selected pipelines, have been collected in a single database. The later contains data such as pipelines characteristics, local cathodic protection parameters at the time of excavation, coating defect description if any, characterization of

  2. Time dependence of tunnel statistics and the energy resolution of superconducting tunnel junctions (United States)

    Verhoeve, P.; Hartog, R. den; Kozorezov, A.; Martin, D.; van Dordrecht, A.; Wigmore, J. K.; Peacock, A.


    Multiple tunneling of quasiparticle charge carriers in a superconducting tunnel junction (STJ) enhances the signal generated by a photon absorption event. It is also an additional source of noise, responsible for a substantial degradation of the energy resolution. Although tunneling is a binomial chance process, governed by a constant tunneling probability, the resulting cumulative statistics of tunnelled quasiparticles depend on time. In particular, the variance of the total number of tunneled quasiparticles reaches a minimum after a finite integration time, corresponding to a minimum in the spectral linewidth. Since the intrinsic energy resolution of the present generation of STJs is mainly limited by the scatter on the number of tunneled quasiparticles, the improvement of the tunnel noise can be experimentally tested by variation of the pulse integration time. An analytical theory is developed that describes the relation between the tunnel noise and the transfer function of the pulse integration hardware for an STJ characterized by a quasiparticle tunnel and loss time in each electrode. We present experiments that demonstrate that the noise contribution from multiple tunnelling is not constant during the time that the quasiparticles are present in the STJ, and that by proper filtering of the STJ pulses the tunnel noise can be optimized at a level which lies well below the canonical tunnel limit.

  3. More about tunnelling times and superluminal tunnelling (Hartmann effect)

    Energy Technology Data Exchange (ETDEWEB)

    Olkhovsky, V.S. [Ukrainian Akademy of Sciences, Kiev (Ukraine). Inst. for Nuclear Research]|[INFN-Sezione di Catania (Italy); Recami, E. [Bergamo Univ. (Italy). Facolta` di Ingegneria]|[State Univ. at Campinas, Campinas (Brazil); Raciti, F. [Catania Univ. (Italy); Zaichenko, A. [Ukrainian Akademy of Sciences, Kiev (Ukraine). Inst. for Nuclear Reserch


    Aims of the present paper are: (i) presenting and analysing the results of various numerical calculations on the penetration and return times <{tau}{sub Pen}>, <{tau}{sub Ret}>, during tunnelling inside a rectangular potential barrier, for various penetration depths x{sub f}; (ii) putting forth and discussing suitable definitions, besides of the mean values, also of the variances (or dispersions) D{sub {tau}T} and D{sub {tau}R} for the time durations of transmission and reflection processes; (iii) mentioning, moreover, that our definition <{tau}{sub T}> for the average transmission time results to constitute an improvement of the ordinary dwell- time formula; (iv) commenting, at last, on the basis of the new numerical results, upon some recent criticism by C.R. Leavens. The paper stresses that numerical evaluations confirm that the approach implied, and implies, the existence of the Hartmann effect: an effect that in these days (due to the theoretical connections between tunnelling and evanescent-wave propagation) is receiving - at Cologne, Berkeley, Florence and Vienna - indirect, but quite interesting, experimental verification.

  4. Numerical analysis of surface subsidence in asymmetric parallel highway tunnels

    Directory of Open Access Journals (Sweden)

    Ratan Das


    Full Text Available Tunnelling related hazards are very common in the Himalayan terrain and a number of such instances have been reported. Several twin tunnels are being planned for transportation purposes which will require good understanding for prediction of tunnel deformation and surface settlement during the engineering life of the structure. The deformational behaviour, design of sequential excavation and support of any jointed rock mass are challenging during underground construction. We have raised several commonly assumed issues while performing stability analysis of underground opening at shallow depth. For this purpose, Kainchi-mod Nerchowck twin tunnels (Himachal Pradesh, India are taken for in-depth analysis of the stability of two asymmetric tunnels to address the influence of topography, twin tunnel dimension and geometry. The host rock encountered during excavation is composed mainly of moderately to highly jointed grey sandstone, maroon sandstone and siltstones. In contrast to equidimensional tunnels where the maximum subsidence is observed vertically above the centreline of the tunnel, the result from the present study shows shifting of the maximum subsidence away from the tunnel centreline. The maximum subsidence of 0.99 mm is observed at 4.54 m left to the escape tunnel centreline whereas the maximum subsidence of 3.14 mm is observed at 8.89 m right to the main tunnel centreline. This shifting clearly indicates the influence of undulating topography and in-equidimensional noncircular tunnel.

  5. Probing spin-polarized tunneling at high bias and temperature with a magnetic tunnel transistor

    NARCIS (Netherlands)

    Park, B.G.; Banerjee, T.; Min, B.C.; Sanderink, Johannes G.M.; Lodder, J.C.; Jansen, R.


    The magnetic tunnel transistor (MTT) is a three terminal hybrid device that consists of a tunnel emitter, a ferromagnetic (FM) base, and a semiconductor collector. In the MTT with a FM emitter and a single FM base, spin-polarized hot electrons are injected into the base by tunneling. After

  6. Observed positive correlation between Epstein-Barr virus infection and focal choroidal excavation. (United States)

    Savastano, Maria Cristina; Rispoli, Marco; Di Antonio, Luca; Mastropasqua, Leonardo; Lumbroso, Bruno


    To evaluate a possible correlation between focal choroidal excavation and Epstein-Barr virus (EBV) infection. Three eyes of three patients underwent a comprehensive ophthalmologic examination including visual field testing, color fundus photography, optical coherence tomography (OCT), fluorescein angiography and indocyanine green angiography. In addition, hematological and viral infectivity were also evaluated. Two females and one male with a mean age of 53.6 ± 5.6 years were studied. In all patients, both the anterior and posterior segment evaluations were unremarkable except for the presence of a spot with focal retinal pigment epithelium (RPE) alteration. In patients 1 and 2, OCT disclosed a normal neuroretinal structure above the lesion and a focal 'punch-out' choroidal lesion with total absence of the RPE coupled with a localized hyporeflectivity in the subretinal space. In two of the three patients, OCT showed normal outer retinal layers, including the photoreceptor layer and the external limiting membrane with a hyporeflective space under the inner segment/outer segment (IS/OS) junction. In one patient, the retinal structure appeared to descend down into the choroidal excavation with an absence of the IS/OS junction and RPE. Moreover, the outer retinal layers appeared to be deformed. In all three patients, the choriocapillaris and choroid showed significant defects as if 'punched out' and the scleral boundary was more evident. In all three patients, an active EBV infection was confirmed by hematological investigation. In all our patients with focal choroid anomalies, such as choroidal excavation observed by OCT, a systemic infection by the EBV was detected. A larger number of similar cases are necessary to corroborate these preliminary observations.

  7. Excavation and drying of compressed peat; Tiivistetyn turpeen nosto ja kuivaus

    Energy Technology Data Exchange (ETDEWEB)

    Erkkilae, A.; Hillebrand, K.; Nurmi, H.; Frilander, P. [VTT Energy, Jyvaeskylae (Finland)


    The aim of this three year project (1993 - 95) is to develop an energy economical excavation method for compressed peat, by which it is possible to improve the peat production efficiency. The main research areas of the project are the drying of compressed peat and the compression of the peat. The optimal density, the load carrying capacity, the degree of maceration and the shape of the drying layer of the milled compressed peat will be determined in the drying research. Energy economical excavation, maceration and compression method, by which it is possible to optimize the drying layer, will be sought using peat compression research and equipment research carried out in laboratory. An experimental model for compressed milled layer, which was in contact with the field, made of Carex peat, was compiled in 1993. Compression tests were made using roller-press equipment, and peat treatability tests with a piston- press and DMTA equipment. An experimental drying model for compressed peat layer (C-t, H7), which is partially isolated from the field, was compiled in 1994. Means for reduction of energy consumption of extrusion were sought in compression studies of 1994 by investigating the friction between peat and 20 different materials and surface coatings, and by studying the effect of electric current on the friction between peat and a nozzle. Additionally, a peat excavation research equipment was constructed, by which the factors effecting on the forming of peat were studied and extruded compressed peat was produced using a nozzle of about 1.0 m width

  8. Focal choroidal excavation:a preliminary interpretation based on clinic and review

    Directory of Open Access Journals (Sweden)

    Guang-Hui Liu


    Full Text Available AIM:To describe the clinical and imaging characteristics associated with focal choroidal excavation (FCE, analyze the possible complication, and interpret its probable etiopathogenesis.METHODS:Retrospective descriptive case series of 37 eyes of 32 patients with FCE. Findings of spectral-domain optical coherence tomography (SD-OCT, fluorescein angiography, indocyanine green angiography, and clinical features were analyzed.RESULTS: All patients were Chinese. Five patients (15.6% were bilaterally involved. Patients’ ages ranged from 7 to 66y. Refractive error ranged between +2.0 D and −11.0 D. Mean best-corrected visual acuity was 0.6 (range, 0.1 to 1.2. Fundus examinations exhibited mild-moderate localized pigmentary disturbances in the corresponding area of 17 eyes. Fluorescein angiography performed in 18 patients showed varying degrees of hyperfluorescence and hypofluorescence related to a range of retinal pigment epithelium (RPE alterations. Indocyanine green angiography performed in 7 patients showed hypofluorescence at the excavation. SD-OCT demonstrated choroidal excavation in all 37 eyes. Twenty-nine eyes showed a single lesion of FCE, and three eyes showed 2-3 separated lesions. Fifteen eyes showed separation between the photoreceptor tips and RPE consistent with nonconforming FCE. Central serous chorioretinopathy (CSC, n=1 and choroidal neovascularization (CNV, n=1 developed during follow-up.CONCLUSION:FCE could be interpreted as congenital focal choroidal dysplasia involving the RPE, choriocapillaris, and photoreceptor associated with the faulty anatomy. The abnormal anatomy of FCE was similar to anatomy at risk of CSC and CNV.

  9. Deformation and failure mechanism of excavation in clay subjected to hydraulic uplift

    CERN Document Server

    Hong, Yi


    This book presents the latest experimental and numerical analysis work in the field of ground deformation and base instability of deep excavations in soft clay subjected to hydraulic uplift. The authors’ latest research findings, based on dimensional analyses, well-instrumented full-scale field tests, systematic coupled-consolidation finite element analyses and centrifuge tests are reported. This book shows how to systematically approach a complex geotechnical problem, from identifying existing problems, reviewing literature, to dimensional and numerical analyses, validation through full-scale testing and centrifuge model testing. The methodologies are also introduced as major tools adopted in geotechnical research.

  10. Towards a web-based archaeological excavation platform for smartphones: review and potentials. (United States)

    Styliaras, Georgios


    The paper conducts a review questioning the usability of a web-based platform supporting archaeological excavations and related fields, which will execute on smartphones. Based on the thorough review and comparison of related work, the basic features of such a platform are outlined. The platform should support documenting content on an underlying XML database through a content management system, producing and exchanging notes, map interaction, use of a shared whiteboard, collaboration among archaeologists etc. The architecture of the platform is presented along with two case studies supporting usual practices on an archaeological field, some primary evaluation results and future work.

  11. Snow and ice blocking of tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Lia, Leif


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

  12. Caries-removal effectiveness and minimal-invasiveness potential of caries-excavation techniques: a micro-CT investigation. (United States)

    Neves, Aline de A; Coutinho, Eduardo; De Munck, Jan; Van Meerbeek, Bart


    To determine the caries-removal effectiveness (CRE) and minimal-invasiveness potential (MIP) of contemporary caries-removal techniques. Carious molars were scanned using micro-CT, after which dentine caries was removed by 9 contemporary caries-removal techniques. The micro-CT was repeated and CRE was determined on basis of the relative volume of residual caries and the mineral density (MD) at the cavity floor. MIP was determined by measuring the cavity size relative to the initial size of the caries lesion. CRE and MIP varied most for the Er:YAG laser (Kavo) despite its laser-induced fluorescence (LIF) feedback system. Whilst some specimens revealed much residual caries, others showed over-excavation into sound dentine. With the highest Relative Cavity Size, the Er:YAG laser presented the lowest MIP. Rotary/oscillating instruments revealed a more favourable CRE with some tendency towards over-excavation, except for CeraBur (Komet-Brasseler) and Cariex (Kavo) that typically left caries at the cavity floor and cavity walls, respectively. Chemo-mechanical excavation aided by conventional metal excavators (Carisolv, MediTeam; exp. SFC-V and SFC-VIII, 3M-ESPE) combined best CRE with MIP. When however a plastic excavator was used along with exp. SFC-VIII, caries was less completely removed. Er:YAG-laser aided by LIF resulted in non-selective caries removal. Rotary/oscillating caries removal may lead to over-excavation, especially when burs are combined with Caries Detector (Kuraray). This risk for over-excavation is reduced when a tungsten-carbide bur is solely used. On the contrary, Cariex (Kavo) and CeraBur showed a tendency for under-preparation. Chemo-mechanical methods were most selective in removing caries, whilst preserving sound tissue. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Pain and carpal tunnel syndrome. (United States)

    Duckworth, Andrew D; Jenkins, Paul J; Roddam, Philip; Watts, Adam C; Ring, David; McEachan, Jane E


    Pain is not a classical symptom of carpal tunnel syndrome (CTS), with the exception of numbness that is so intense that it is described by patients as painful. The primary aim of our study was to determine which factors correlated with pain for patients diagnosed with CTS. We prospectively assessed all patients diagnosed with CTS in our unit over a 1-year period. We recorded demographic details for all patients, including past medical history, body mass index, smoking, and occupation. The diagnosis and severity of carpal tunnel syndrome were established through a combination of history, clinical assessment, and nerve conduction studies. Of 275 patients diagnosed and treated for CTS, 183 were women (67%), the mean age was 55 years (range, 22-87 y), and 166 cases were bilateral (60%). The mean body mass index was 29.5 kg/m2 (range, 17-48 kg/m2), and 81 patients smoked (30%). Patients completed a Short Form-McGill pain questionnaire (SF-MPQ) as a measure of pain at initial presentation. We assessed outcome 1 year after intervention using the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score. We found no association between pain according to the SF-MPQ and the positive clinical signs of CTS or positive nerve conduction studies. Multivariate analysis demonstrated that smoking and bilateral disease independently correlated with the overall SF-MPQ, with similar findings on subanalysis. Independent factors associated with an increased improvement in the QuickDASH at 1 year were the presentation QuickDASH score, positive nerve conduction studies, and smoking. The only independent factors that correlated with pain at presentation of CTS were smoking and bilateral disease. Pain according to the SF-MPQ was not associated with classical clinical findings of the disease or with positive findings on nerve conduction testing. Prognostic I. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  14. Hawking Radiation and Classical Tunneling

    CERN Document Server

    Tracy, Eugene R


    Acoustic waves in fluids undergoing the transition from sub- to supersonic flow satisfy governing equations similar to those for light waves in the immediate vicinity of a black hole event horizon. This acoustic analogy has been used by Unruh and others as a conceptual model for `Hawking radiation.' Here we use variational methods, originally introduced by Brizard for the study of linearized MHD, and ray phase space methods, to analyze linearized acoustics in the presence of background flows. The variational formulation endows the evolution equations with natural Hermitian and symplectic structures that prove useful for later analysis. We derive a $2\\times 2$ normal form governing the wave evolution in the vicinity of the `event horizon.' This shows that the acoustic model can be reduced locally (in ray phase space) to a standard (scalar) tunneling process weakly coupled to a unidirectional non-dispersive wave (the `incoming wave'). Given the normal form, the Hawking `thermal spectrum' can be derived by invok...

  15. The influence of cathode excavation of cathodic arc evaporator on thickness uniformity and erosion products angle distribution

    Directory of Open Access Journals (Sweden)

    D. V. Duhopel'nikov


    Full Text Available Cathodic arc evaporators are used for coating with functional films. Prolonged or buttend evaporators may be used for this purposes. In butt-end evaporator the cathode spots move continuously on the cathode work surface and evaporate cathode material. High depth excavation profile forms on the cathode work surface while the thick coating precipitation (tens or hundreds of microns. The cathode excavation profile is shaped like a “cup” with high walls for electrostatic discharge stabilization systems with axial magnetic fields. Cathode spots move on the bottom of the “cup”. It is very likely that high “cup” walls are formed as a result of lasting work time influence on the uniformity of precipitated films.In the present work the influence of excavation profile walls height on the uniformity of precipitated coating was carried out. The high profile walls are formed due to lasting work of DC vacuum arc evaporator. The cathode material used for tests was 3003 aluminum alloy. The extended substrate was placed parallel to the cathode work surface. Thickness distribution along the substrate length with the new cathode was obtained after 6 hours and after 12 hours of continuous operation.The thickness distribution of precipitated coating showed that the cathode excavation has an influence on the angular distribution of the matter escaping the cathode. It can be clearly seen from the normalized dependence coating thickness vs the distance from the substrate center. Also the angular distribution of the matter flow from the cathode depending on the cathode working time was obtained. It was shown that matter flow from the cathode differs from the LambertKnudsen law. The more the cathode excavation the more this difference.So, cathode excavation profile has an influence on the uniformity of precipitated coating and it is necessary to take in account the cathode excavation profile while coating the thick films.

  16. Excavator Design Validation (United States)

    Pholsiri, Chalongrath; English, James; Seberino, Charles; Lim, Yi-Je


    The Excavator Design Validation tool verifies excavator designs by automatically generating control systems and modeling their performance in an accurate simulation of their expected environment. Part of this software design includes interfacing with human operations that can be included in simulation-based studies and validation. This is essential for assessing productivity, versatility, and reliability. This software combines automatic control system generation from CAD (computer-aided design) models, rapid validation of complex mechanism designs, and detailed models of the environment including soil, dust, temperature, remote supervision, and communication latency to create a system of high value. Unique algorithms have been created for controlling and simulating complex robotic mechanisms automatically from just a CAD description. These algorithms are implemented as a commercial cross-platform C++ software toolkit that is configurable using the Extensible Markup Language (XML). The algorithms work with virtually any mobile robotic mechanisms using module descriptions that adhere to the XML standard. In addition, high-fidelity, real-time physics-based simulation algorithms have also been developed that include models of internal forces and the forces produced when a mechanism interacts with the outside world. This capability is combined with an innovative organization for simulation algorithms, new regolith simulation methods, and a unique control and study architecture to make powerful tools with the potential to transform the way NASA verifies and compares excavator designs. Energid's Actin software has been leveraged for this design validation. The architecture includes parametric and Monte Carlo studies tailored for validation of excavator designs and their control by remote human operators. It also includes the ability to interface with third-party software and human-input devices. Two types of simulation models have been adapted: high-fidelity discrete

  17. Results of Hazardous and Mixed Waste Excavation from the Chemical Waste Landfill

    Energy Technology Data Exchange (ETDEWEB)

    Young, S. G.; Schofield, D. P.; Kwiecinski, D.; Edgmon, C. L.; Methvin, R.


    This paper describes the results of the excavation of a 1.9-acre hazardous and mixed waste landfill operated for 23 years at Sandia National Laboratories, Albuquerque, New Mexico. Excavation of the landfill was completed in 2 1/2 years without a single serious accident or injury. Approximately 50,000 cubic yards of soil contaminated with volatile and semi-volatile organics, metals, polychlorinated biphenyl compounds, and radioactive constituents was removed. In addition, over 400 cubic yards of buried debris was removed, including bulk debris, unknown chemicals, compressed gas cylinders, thermal and chemical batteries, explosive and ordnance debris, pyrophoric materials and biohazardous waste. Removal of these wastes included negotiation of multiple regulations and guidances encompassed in the Resource Conservation and Recovery Act (RCRA), the Toxic Substances Control Act (TSCA), and risk assessment methodology. RCRA concepts that were addressed include the area of contamination, permit modification, emergency treatment provision, and listed waste designation. These regulatory decisions enabled the project to overcome logistical and programmatic needs such as increased operational area, the ability to implement process improvements while maintaining a record of decisions and approvals.

  18. Excavation on the Moon: Regolith Collection for Oxygen Production and Outpost Site Preparation (United States)

    Caruso, John J.; Spina, Dan C.; Greer, Lawrence C.; John, Wentworth T.; Michele, Clem; Krasowski, Mike J.; Prokop, Norman F.


    The development of a robust regolith moving system for lunar and planetary processing and construction is critical to the NASA mission to the Moon and Mars. Oxygen production may require up to 200 metric tons of regolith collection per year; outpost site development may require several times this amount. This paper describes progress in the small vehicle implement development and small excavation system development. Cratos was developed as a platform for the ISRU project to evaluate the performance characteristics of a low center of gravity, small (0.75m x 0.75m x 0.3m), low-power, tracked vehicle performing excavation, load, haul, and dump operations required for lunar ISRU. It was tested on loose sand in a facility capable of producing level and inclined surfaces, and demonstrated the capability to pick up, carry, and dump sand, allowing it to accomplish the delivery of material to a site. Cratos has demonstrated the capability to pick up and deliver simulant to a bury an inflatable habitat, to supply an oxygen production plant, and to build a ramp.

  19. Characterisation of excavated fine fraction and waste composition from a Swedish landfill. (United States)

    Jani, Yahya; Kaczala, Fabio; Marchand, Charlotte; Hogland, Marika; Kriipsalu, Mait; Hogland, William; Kihl, Anders


    The present research studies the characterisation and the physico-chemical properties of an excavated fine fraction (landfill, the Högbytorp. The results showed that the fine fraction represents 38% by mass of the total excavated wastes and it contains mainly soil-type materials and minerals. Higher concentrations of zinc, copper, barium and chromium were found with concentrations higher than the Swedish Environmental Protection Agency (EPA) for contaminated soil. The found moisture and organic contents of the fine fraction were 23.5% and 16.6%, respectively. The analysed calorific value (1.7 MJ kg(-1)), the potential of CH4 (4.74 m(3) t(-1) dry matter) and Total Organic Carbon (TOC) (5.6%) were low and offer low potential of energy. Sieving the fine fraction further showed that 80% was smaller than 2 mm. The fine represents a major fraction at any landfill (40%-70%), therefore, characterising the properties of this fraction is essential to find the potential of reusing/recycling or safely redisposing. © The Author(s) 2016.

  20. Comparative clinical evaluation of the efficacy of a new method for caries diagnosis and excavation. (United States)

    Peskersoy, Cem; Turkun, Murat; Onal, Banu


    The purpose of this study is to compare the efficiency of fluorescence-aided caries excavation (FACE) to remove carious dentin primary teeth with that of conventional methods. After caries excavation was carried out, dentin surfaces were conventionally inspected using visual tactile criteria and 415 cavities which were classified as caries-free, re-inspected with Face-Light and caries detector dye (CDD) methods. Orange-red fluorescing areas classified as carious dentin, as well as stained carious dentin. All the data were recorded according to localization of the caries and determination efficiency of the methods. X(2) test was used to compare the mean values of both Face-Light and dye applications, while Wilcoxon test performed to evaluate the effectiveness for each diagnostic method. A total of 273 patients with 415 Class II (OM/OD) cavities (1.65 ± 0.52 teeth per patient) with carious lesions in molar and premolar teeth, were examined. Out of 415 teeth, in 149 teeth (35.9%) no caries findings had been illustrated. While FACE detected remaining carious or partially removed areas in 237 teeth (57.2%), CDD stained only 29 teeth by itself (P < 0.05). In conclusion, FACE has a higher detectability compared to visual inspection and caries detector dye in diagnosis and removal of carious dentin.

  1. A Basic Robotic Excavator (the Glenn Digger): Description, Design, and Initial Operation (United States)

    Bauman, Steve; Newman, Paul; Izadnegahdar, Alain; Johnson, Kyle; Abel, Phillip


    This paper describes the design, commercial part selections, fabrication, assembly, installation, and initial operation of a two degree of freedom robotic excavator. Colloquially referred to as "the NASA Glenn Digger," it was designed specifically to be mounted onto, and to operate with, the then newly developed Centaur 2 robotic mobility base. The excavator, when mounted to Centaur 2, is designed to scoop loose regolith from the terrain, raise its loaded bucket up and dump the load into a hopper of at least a 1-m-height. The hopper represents the input to a machine that would process the raw material, such as to produce oxygen from lunar regolith as would be required for long-term lunar habitation. This equipment debuted at the annual Research and Technology Studies ("Desert RATS", Ref. 1) event held north of Flagstaff, Arizona, in September of 2010, when the Digger was successfully joined to Centaur 2 and the shoveling articulation was demonstrated. During 2011, the hardware was modified for added strength, strain gauges were added to measure loads, and the controls were improved in preparation for the 2011 Desert RATS event, where additional "field operations" experience was gained.

  2. Numerical Simulation of Blast Vibration and Crack Forming Effect of Rock-Anchored Beam Excavation in Deep Underground Caverns

    Directory of Open Access Journals (Sweden)

    XinPing Li


    Full Text Available Aiming at surrounding rock damage induced by dynamic disturbance from blasting excavation of rock-anchored beam in rock mass at moderate or far distance in underground cavern, numerical model of different linear charging density and crustal stress in underground cavern is established by adopting dynamic finite element software based on borehole layout, charging, and rock parameter of the actual situation of a certain hydropower station. Through comparison in vibration velocity, contour surface of rock mass excavation, and the crushing extent of excavated rock mass between calculation result and field monitoring, optimum linear charging density of blast hole is determined. Studies are also conducted on rock mass vibration in moderate or far distance to blasting source, the damage of surrounding rock in near-field to blasting source, and crushing degree of excavated rock mass under various in situ stress conditions. Results indicate that, within certain range of in situ stress, the blasting vibration is independent of in situ stress, while when in situ stress is increasing above certain value, the blasting vibration velocity will be increasing and the damage of surrounding rock and the crushing degree of excavated rock mass will be decreasing.

  3. Microindentation hardness and calcium/phosphorus ratio of dentin following excavation of dental caries lesions with different techniques. (United States)

    Katirci, Gunseli; Ermis, R Banu


    The aim of this in vitro study was to evaluate the microindentation hardness and chemical composition of residual dentin left at the cavity bottom following removal of carious dentin using the Carisolv chemomechanical and Er:YAG laser caries excavation methods in comparison with the conventional tungsten-carbide bur excavation. Sixty-nine extracted permanent teeth with occlusal dentin caries were assigned into three groups according to caries removal technique. Carious dentin excavation was guided by tactile method and a caries-staining dye. In stereomicroscope images (100×) of the samples, the presence or absence of residual caries was defined. The Knoop hardness value of the cavity floor was determined and atomic analysis of treated cavities was performed by energy dispersive X-ray spectroscopy. The Knoop hardness value of residual dentin left at the cavity bottom was lower (One-way ANOVA, Dunnett-C, p laser excavations (Kruskal-Wallis, Mann-Whitney U, p  0.05). The results indicated that Er:YAG laser was more comparable to conventional bur excavation than chemomechanical method in the efficacy of caries removal with regard to microindentation hardness of remaining dentin and both Carisolv gel and Er:YAG laser did not alter chemical composition of residual dentin in the treated cavities.

  4. Rudolf Hermann, wind tunnels and aerodynamics (United States)

    Lundquist, Charles A.; Coleman, Anne M.


    Rudolf Hermann was born on December 15, 1904 in Leipzig, Germany. He studied at the University of Leipzig and at the Aachen Institute of Technology. His involvement with wind tunnels began in 1934 when Professor Carl Wieselsberger engaged him to work at Aachen on the development of a supersonic wind tunnel. On January 6, 1936, Dr. Wernher von Braun visited Dr. Hermann to arrange for use of the Aachen supersonic wind tunnel for Army problems. On April 1, 1937, Dr. Hermann became Director of the Supersonic Wind Tunnel at the Army installation at Peenemunde. Results from the Aachen and Peenemunde wind tunnels were crucial in achieving aerodynamic stability for the A-4 rocket, later designated as the V-2. Plans to build a Mach 10 'hypersonic' wind tunnel facility at Kochel were accelerated after the Allied air raid on Peenemunde on August 17, 1943. Dr. Hermann was director of the new facility. Ignoring destruction orders from Hitler as WWII approached an end in Europe, Dr. Hermann and his associates hid documents and preserved wind tunnel components that were acquired by the advancing American forces. Dr. Hermann became a consultant to the Air Force at its Wright Field in November 1945. In 1951, he was named professor of Aeronautical Engineering at the University of Minnesota. In 1962, Dr. Hermann became the first Director of the Research Institute at the University of Alabama in Huntsville (UAH), a position he held until he retired in 1970.

  5. Carpal tunnel syndrome - anatomical and clinical correlations. (United States)

    Iskra, Tomasz; Mizia, Ewa; Musial, Agata; Matuszyk, Aleksandra; Tomaszewski, Krzysztof A


    Carpal tunnel syndrome (CTS) is the most common and widely known of the entrapment neuropathies in which the body's peripheral nerves are compressed. Common symptoms of CTS involve the hand and result from compression of the median nerve within the carpal tunnel. In general, CTS develops when the tissues around the median nerve irritate or compress on the nerve along its course through the carpal tunnel, however often it is very difficult to determine cause of CTS. Proper treatment (conservative or surgical) usually can relieve the symptoms and restore normal use of the wrist and hand.

  6. Tunneling methods used at the railway tunnels construction in Slovak republic

    Directory of Open Access Journals (Sweden)

    Jozef Čížik


    Full Text Available Rail transport is an energy-efficient and capital-intensive means of mechanized land transport. Methods of tunneling vary with the nature of the material to be cut through. When soft earth is encountered, the excavation is timbered for support as the work advances; the timbers are sometimes left as a permanent lining for the tunnel. Another method is to cut two parallel excavations in which the side walls are constructed first. Arches connecting them are then built as the material between them is extracted. Portions of the unexcavated center, left temporarily for support, may be removed later. A tunnel cut through rock frequently requires no lining. Often, to speed construction, work is started at both ends. This poses no problem with the cut-and-cover method, but when the tunnel is bored from within, it must be assured that the tubes will actually meet in the center. Modern methods accomplish this with high precision.

  7. Prevention and Control of Highway Tunnel Fires (United States)


    This study investigates steps that can be taken to reduce the risk, damage, and : fatalities from fires in existing and future highway tunnels and the effect of : unrestricted transit of hazardous materials through them. The history of : highway tunn...

  8. Computational Analysis of Protein Tunnels and Channels. (United States)

    Brezovsky, Jan; Kozlikova, Barbora; Damborsky, Jiri


    Protein tunnels connecting the functional buried cavities with bulk solvent and protein channels, enabling the transport through biological membranes, represent the structural features that govern the exchange rates of ligands, ions, and water solvent. Tunnels and channels are present in a vast number of known proteins and provide control over their function. Modification of these structural features by protein engineering frequently provides proteins with improved properties. Here we present a detailed computational protocol employing the CAVER software that is applicable for: (1) the analysis of tunnels and channels in protein structures, and (2) the selection of hot-spot residues in tunnels or channels that can be mutagenized for improved activity, specificity, enantioselectivity, or stability.

  9. Design aspects of the Alpha Repository. V. Suite selection and cost analysis of excavation/hauling systems

    Energy Technology Data Exchange (ETDEWEB)

    Zeller, T.J.; Grams, W.H.


    The various types of haulage and excavation equipment that may be suitable for use in the development and excavation of the Alpha repository are described with discussion of the advantages, disadvantages, expected costs, availability, and special features of each. The various equipment suites are delineated, and the costs of mining and transportation of the salt are presented and discussed. Individual manufacturers contacted and equipment considered are listed. Most of the equipment is ''off-the-shelf''; however, some manufactuers were contacted that do custom work because of their expertise in salt mining equipment. The costs of custom equipment are comparable to those for standard equipment.

  10. Treatment of deep caries lesions in adults: randomized clinical trials comparing stepwise vs. direct complete excavation, and direct pulp capping vs. partial pulpotomy. (United States)

    Bjørndal, Lars; Reit, Claes; Bruun, Gitte; Markvart, Merete; Kjaeldgaard, Marianne; Näsman, Peggy; Thordrup, Marianne; Dige, Irene; Nyvad, Bente; Fransson, Helena; Lager, Anders; Ericson, Dan; Petersson, Kerstin; Olsson, Jadranka; Santimano, Eva M; Wennström, Anette; Winkel, Per; Gluud, Christian


    Less invasive excavation methods have been suggested for deep caries lesions. We tested the effects of stepwise vs. direct complete excavation, 1 yr after the procedure had been carried out, in 314 adults (from six centres) who had received treatment of a tooth with deep caries. The teeth had caries lesions involving 75% or more of the dentin and were centrally randomized to stepwise or direct complete excavation. Stepwise excavation resulted in fewer pulp exposures compared with direct complete excavation [difference: 11.4%, 95% confidence interval (CI) (1.2; 21.3)]. At 1 yr of follow-up, there was a statistically significantly higher success rate with stepwise excavation, with success being defined as an unexposed pulp with sustained pulp vitality without apical radiolucency [difference: 11.7%, 95% CI (0.5; 22.5)]. In a subsequent nested trial, 58 patients with exposed pulps were randomized to direct capping or partial pulpotomy. We found no significant difference in pulp vitality without apical radiolucency between the two capping procedures after more than 1 yr [31.8% and 34.5%; difference: 2.7%, 95% CI (-22.7; 26.6)]. In conclusion, stepwise excavation decreases the risk of pulp exposure compared with direct complete excavation. In view of the poor prognosis of vital pulp treatment, a stepwise excavation approach for managing deep caries lesions is recommended.

  11. Tunneling and Transport in Nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, Allen M. [Univ. of Minnesota, Minneapolis, MN (United States)


    The goal of this program was to study new physical phenomena that might be relevant to the performance of conductive devices and circuits of the smallest realizable feature sizes possible using physical rather than biological techniques. Although the initial scientific work supported involved the use of scanning tunneling microscopy and spectroscopy to ascertain the statistics of the energy level distribution of randomly sized and randomly shaped quantum dots, or nano-crystals, the main focus was on the investigation of selected properties, including superconductivity, of conducting and superconducting nanowires prepared using electron-beam-lithography. We discovered a magnetic-field-restoration of superconductivity in out-of-equilibrium nanowires driven resistive by current. This phenomenon was explained by the existence of a state in which dissipation coexisted with nonvanishing superconducting order. We also produced ultra-small superconducting loops to study a predicted anomalous fluxoid quantization, but instead, found a magnetic-field-dependent, high-resistance state, rather than superconductivity. Finally, we developed a simple and controllable nanowire in an induced charged layer near the surface of a masked single-crystal insulator, SrTiO3. The layer was induced using an electric double layer transistor employing an ionic liquid (IL). The transport properties of the induced nanowire resembled those of collective electronic transport through an array of quantum dots.

  12. The Report of Fourth Season Excavations at Tol- e Bondu and Discovery of a Temple, West of Fars, Iran

    Directory of Open Access Journals (Sweden)

    Ali Atabaki


    Full Text Available This paper underlines the important archaeological evidence unearthed from four seasons of excavation at Tol-e Bondu, located at Rostam-Du, Noorabad city, Fars province. The most significant information acquired from this excavation is the discovery of a temple from the 16th layer, exactly similar to the one from the middle phase of the Elamite culture. This paper discusses the structures and other features showing similarity between the two regions. Studying the history of the Elamites via relief and inscriptions in Mesopotamia leads us to the belief that performing religious ceremonies played an important role in the civilization and culture of Elam.

  13. Tunneling into quantum wires: Regularization of the tunneling Hamiltonian and consistency between free and bosonized fermions (United States)

    Filippone, Michele; Brouwer, Piet W.


    Tunneling between a point contact and a one-dimensional wire is usually described with the help of a tunneling Hamiltonian that contains a δ function in position space. Whereas the leading-order contribution to the tunneling current is independent of the way this δ function is regularized, higher-order corrections with respect to the tunneling amplitude are known to depend on the regularization. Instead of regularizing the δ function in the tunneling Hamiltonian, one may also obtain a finite tunneling current by invoking the ultraviolet cutoffs in a field-theoretic description of the electrons in the one-dimensional conductor, a procedure that is often used in the literature. For the latter case, we show that standard ultraviolet cutoffs lead to different results for the tunneling current in fermionic and bosonized formulations of the theory, when going beyond leading order in the tunneling amplitude. We show how to recover the standard fermionic result using the formalism of functional bosonization and revisit the tunneling current to leading order in the interacting case.

  14. A Survey of Commercially Available and Proven Remote Control Machines for Excavation and Recovery of Buried Ordnance

    Energy Technology Data Exchange (ETDEWEB)

    Pruneda, C; Bilstrom, A


    The issue of unexploded ordnance excavation and removal is complicated by the interaction between the independent robotics systems (e.g. manipulator, sensors, and software). A review of commercially available robotic systems highlights the specificity of the design and intent of each for the application and problem being addressed. Although multiple parties, including universities, research institutes, and manufacturers worldwide are concerned with removing explosive ordnance (EOD) and unexploded ordnance (UXO), the exact details of the problems and tasks at each site differ between projects, even slightly. The risks associated with the excavation and removal of ordnance require a level of robustness that necessitates extensive testing and engineering despite project similarities. Based on the experience of researchers, the integration of systems at unique excavation sites will be the critical element of the project to ensure the safe and robust removal of buried ordnance. Although this report touches on some systems integration issues to a limited degree, the report at this stage is primarily a survey of commercially available, proven robotics components and systems for the excavation and recovery of buried ordnance.

  15. Comparison of the Seismic Effects of Soil Disturbance and Void Space Over Shallow Cut-and-Cover Tunnels (United States)

    Bonal, N. D.; Abbott, R. E.; Preston, L. A.


    Locating subsurface voids using surface seismic methods has been problematic. This study compares changes in seismic data before and after tunnel emplacement using the cut-and-cover method for three separate cylindrical tunnels. Cut-and-cover construction for tunnels used in this project involved excavating a trench in the soil, emplacing a pre-built metal or plastic tunnel, and packing the excavated soil around the tunnel up to the surface. Data from a “disturbed earth” area (cut-and-cover with no emplacement of a tunnel) is also presented to determine if observed changes in seismic waves are due to the void or the disturbance of the soil. 2D surface seismic refraction tomography surveys were collected before and after tunnel emplacement using identical survey parameters and source and receiver locations. Minimal changes in the seismic properties are expected between data collections (10 months apart), therefore all changes in the data are attributed to tunnel emplacement. Preliminary results are presented for three different survey areas and include tunnels of approximately 1 meter in diameter buried to up to 5 meters deep. Tunnel axes are at either 90 degrees or 60 degrees to the survey lines. Differences in receiver spacing with respect to tunnel diameter are also considered. Changes in seismic waveforms, first arrival times, raypath coverage, and P-wave velocities are presented. Synthetic examples and difference images (subtracting the "after" data set from the "before") of velocity and raypath coverage are also shown. First-arriving P-waves do not pass through the void but are diverted through the higher velocity material around it and this disturbance in raypath coverage, as seen in our refraction tomography, is an accurate indicator of subsurface voids. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin company, for the U.S. Department of Energy’s National Nuclear

  16. Clinical Efficiency of Three Caries Removal Systems: Rotary Excavation, Carisolv, and Papacarie. (United States)

    Hegde, Sapna; Kakti, Ateet; Bolar, Dinesh Rao; Bhaskar, Shubha Arehalli


    The removal of dentinal caries using the rotary method of excavation is most often associated with pain and anxiety in children. Chemo-mechanical caries removal may eliminate some of the drawbacks of the rotary technique and improve patient comfort. The purpose of this study was to compare the efficiency of the rotary, Carisolv, and Papacarie methods for caries removal in primary teeth, length of time needed, influence on child behavior, pain perception, and treatment preference of the child. This controlled, split-mouth study with a cross-over design compared three caries removal methods in the primary molars of 50 five- to 12-year-old children. The rotary method was the most efficient and least time-consuming (Pperception, however, was highest with this method (Pcaries removal may be a promising alternative treatment procedure, particularly for anxious young patients.

  17. Nest relocation and excavation in the Florida harvester ant, Pogonomyrmex badius.

    Directory of Open Access Journals (Sweden)

    Walter R Tschinkel

    Full Text Available The Florida harvester ant (Pogonomyrmex badius excavates deep nests in the sandy soils of the Gulf and Atlantic coastal plains. Nest relocations of over 400 colonies in a north Florida coastal plains pine forest were tracked and mapped from 2010 to 2013. Individual colonies varied from one move in two years to four times a year, averaging about one per year. Almost all moves occurred between May and November peaking in July when more than 1% of the colonies moved per day. Move directions were random, and averaged 4 m, with few moves exceeding 10 m. Distance moved was not related to colony size. Over multiple moves, paths were random walks around the original nest location. Relocation is probably intrinsic to the life history of this species, and the causes of relocation remain obscure--the architecture of old and new nests was very similar, and neither the forest canopy nor the density or size of neighbors was correlated with relocation. Monitoring entire relocations (n = 20 showed that they were usually completed in 4 to 6 days. Moves were diurnal, peaking in the mornings and afternoons dipping during mid-day, and ceasing before sundown. Workers excavated the new nest continuously during the daytime throughout the move and beyond. A minority of workers carried seeds, charcoal and brood, with seeds being by far the most common burden. The proportion of burdened workers increased throughout the move. Measured from year to year, small colonies gained size and large ones lost it. Colonies moving more than once in two years lost more size than those moving less often, suggesting that moving may bear a fitness cost. Colony relocation is a dramatic and consistent feature of the life history of the Florida harvester ant, inviting inquiry into its proximal and ultimate causes.

  18. Pilot-Scale Bio-Augmented Aerobic Composting of Excavated Foot-And-Mouth Disease Carcasses

    Directory of Open Access Journals (Sweden)

    Seonghoon Kim


    Full Text Available In the present work, we tested the validity of using novel, bio-augmented, aerobic composting with carcass-degrading microorganisms for the ex situ stabilization of carcasses at pilot scale with previously poorly decomposed carcasses excavated from a 3-year old burial site. The significantly decreased chemical oxygen demand (COD, 160,000 mg/kg to 40,000 mg/kg and inorganic nitrogen species (total nitrogen, 5000 mg/kg to 2000 mg/kg indicated effective bio-stabilization of carcasses by bio-augmented composting. The subsequent germination assays and the quantitative characterization of potentially pathogenic bacteria using NGS (next-generation sequencing showed that the burial–composting sequential system with the carcass-degrading microorganisms and mechanical agitation successfully reduced plant toxicity as well as microbial risk to human health, suggesting that the composting by-product is suitable for farming or/and landfill use(s.


    Directory of Open Access Journals (Sweden)

    Jerko Nuić


    Full Text Available In the construction of devastated and demolished country the want for crushed stone is ever more greater. The opening of new quarryes is subject to strict ecological norms. The location of activity as well as the concept of the mining works represent a matter of consideration. Excavated areas should be shaped in a way to be integrated into immediate and wider environment most conveniently and then be redestinated with the purpose of the economic, sporting-recreation or some other usage. On the existing model in nature (»Široki Čelac« quarry, Novalja on the island of Pag, the specific characteristics of the locality and region have been respected. There have been also given adequate solutions for a possible deposit of communal waste (the paper is published in Croatian.

  20. Excavations in 2014 at Wade Street, Bristol - a documentary and archaeological analysis

    Directory of Open Access Journals (Sweden)

    Nick Corcos


    Full Text Available A staged programme of historical research and archaeological fieldwork, involving a desk-based assessment in 2000 (Smith and Erskine 2000, an evaluation in 2013 (Mason 2013, and an excavation followed by a watching brief in 2014, the latter two by Avon Archaeology Ltd, was undertaken in order to mitigate the archaeological impact of a proposed residential development on a site of 1,260m² at the corner and on the north-west side of Little Anne Street and Wade Street, St Jude’s, Bristol. The site was formerly occupied by residential dwellings, originally established in the very early 18th century as part of a then newly planned development of artisans’ houses. In combination, the data from these studies indicate that the Wade Street site has a history of continuous occupation, from c. 1700 until the buildings on it were removed in the years on either side of the Second World War as part of a so-called 'slum clearance' project. A very small assemblage of medieval pottery recovered from the lower contexts of the site during the excavation hints at some level of activity in the vicinity during the medieval period. This publication offers an opportunity to link the results of the fieldwork to an outline study of a sample of the 19th-century census records, to give a picture of the social dynamics of a highly diverse community in the second half of that century, and which presents a surprisingly mixed picture of both long stability, and incessant change in terms of the movement of people into and out of this part of Wade Street.

  1. The Role of Cell Compartmentalization and Cell Differentiation in Cyanobacterial Excavation of Miineral Carbonates (United States)

    Garcia-Pichel, F.; Guida, B. S.; Couradeau, E.


    The bioerosion of coastal limestones and biogenic carbonates by boring filamentous or pseudo-filamentous cyanobacteria is not only a geomicrobial phenomenon of global proportions, but also plays an important role in the demise of coral reefs, and affects significantly human enterprises like bivalve fisheries. In spite of its importance, the mechanism by which cyanobacteria excavate carbonates constitutes an apparent paradox, in that their metabolism will tend to precipitate carbonates, not dissolved them. We have previously advanced, and obtained evidence for, a mechanism of excavation that relies on the uptake of Ca2+ by cells at the boring front, its trans-cellular transport along the filaments, and its eventual active excretion at the solid/liquid interface. It was postulated that the mechanism involved the strategically organized deployment of Ca2+ transport enzymes like P-type Ca2+ ATPases and Ca2+ channels. Here we present evidence that confirms this basic mechanism, but also reveals that it is based on an unexpected level of cellular complexity. The model organism Mastigocoleus testarum BC008, transports Ca2+ from the mineral to the external medium using a repetitive, polar arrangement of Ca2+ ATPases, localized preferentially on one cellular pole, in a ring conformation on the cell membrane adjacent to the trans-cellular septum, pumping Ca2+ locally towards the periplasmic space, from which it passively enters the next cell. This strain also develops specialized groups of cells, which we named calcicytes, often but not exclusively located at the ends of filaments, that accumulate large concentrations of Ca2+, some 40-fold higher than typical in microbes, and seem to act as sinks or capacitors in the trans-cellular Ca2+ transport. Calcicytes are also characterized by a lack of photosynthetic pigments, and a very high intracellular pH. These cellular adaptations can also be found in evolutionary distant euendoliths such as the pseudofilamentous Hyella sp.

  2. Probabilistic prediction of expected ground condition and construction time and costs in road tunnels

    Directory of Open Access Journals (Sweden)

    A. Mahmoodzadeh


    Full Text Available Ground condition and construction (excavation and support time and costs are the key factors in decision-making during planning and design phases of a tunnel project. An innovative methodology for probabilistic estimation of ground condition and construction time and costs is proposed, which is an integration of the ground prediction approach based on Markov process, and the time and cost variance analysis based on Monte-Carlo (MC simulation. The former provides the probabilistic description of ground classification along tunnel alignment according to the geological information revealed from geological profile and boreholes. The latter provides the probabilistic description of the expected construction time and costs for each operation according to the survey feedbacks from experts. Then an engineering application to Hamro tunnel is presented to demonstrate how the ground condition and the construction time and costs are estimated in a probabilistic way. In most items, in order to estimate the data needed for this methodology, a number of questionnaires are distributed among the tunneling experts and finally the mean values of the respondents are applied. These facilitate both the owners and the contractors to be aware of the risk that they should carry before construction, and are useful for both tendering and bidding.


    Directory of Open Access Journals (Sweden)

    Bethany J. Walker


    Full Text Available Transjordan witnessed significant social and economic changes in the last quarter of the nineteenth century. With the loss of agriculturally-rich territory in Europe, the Ottomans sought to make up for their economic losses by regaining control of their Arab provinces, some regions of which had been autonomous for nearly three hundred years. The application of Tanzimat legislation to the Transjordan was a success, to a large degree, in that it secured tax revenues and contributed to the general security of the region.The application of the 1858 Land Law, in which land was registered in a proprietor’s name for tax purposes, was particularly effective in transforming grazing land to productive agricultural properties. It, moreover, had a significant impact on Transjordanian society which was tribal and largely nomadic. The introduction of direct rule in the region by the Ottoman government transformed traditional tribal life, resulting in the settlement of formerly nomadic groups, the transition to an agrarian way of life, and the opening up of markets formerly inaccessible to indigenous tribal groups. A variety of urban, manufactured goods became readily available to all sectors of society throughout this frontier zone.“Bangles, Beads and Bedouin: Excavating a Late Ottoman Cemetery inJordan” considers the transformation of tribal funerary practices in the Belqa’ of central Jordan. The paper highlights the burial ground of one Transjordanian tribe, identified as the Adwan, excavated at Tall Hisban in 1998. Dated to the late nineteenth century on the basis of coins, this mass grave was one of the last of its kind, as permanent cemeteries replaced seasonal burial grounds by the early twentieth century. The composition of theburial goods indicates that members of the tribe participated in an exchange network that embraced the Red Sea, Greater Syria, and Europe.

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

    Energy Technology Data Exchange (ETDEWEB)

    Teeny, Nicolas


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

  5. Vitelliform focal choroidal excavation. (United States)

    Or, Chris; Forooghian, Farzin


    Focal choroidal excavations (FCE) are characterized by foveal or perifoveal choroid excavations seen on optical coherence tomography (OCT). The authors report a case of FCE associated with a vitelliform lesion within the excavation. A case of FCE associated with a small vitelliform lesion has been described previously, but the larger extent of the vitelliform lesion observed in the current case has not been previously reported. This may represent a novel category of FCE, vitelliform focal choroidal excavation, in which deposition of vitelliform material is associated with its development. Copyright 2014, SLACK Incorporated.

  6. DECOVALEX-THMC Project. Task B. Understanding and characterizing the excavation disturbed zone (EDZ). Phase 2 Report

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, John A. (ed.) [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)]|[Rock Engineering Consultants (United Kingdom); Lanru Jing (ed.) [Royal Institute of Technology, Stockholm (Sweden); Antikainen, Juha [Helsinki University of Technology, Helsinki (Finland); Backers, Tobias [GeoFrames GmbH, (Germany); Baeckstroem, Ann [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)]|[Bergbyggkonsult AB (Sweden); Koyama, Tomofumi [Swedish Nuclear Power Inspectorate, Stockholm (Sweden); Xiating Feng; Pengzhi Pan [Chinese Academy of Sciences (China); Kobayashi, Akira [Kyoto Univ. (Japan); Rinne, Mikael; Baotang Shen [Fracom Ltd. (Finland)


    The DECOVALEX-THMC project is an ongoing international co-operative project that was stared in 2004 to support the development of mathematical models of coupled Thermal (T), Hydrological (H), Mechanical (M) and Chemical (C) processes in geological media for siting potential nuclear fuel waste repositories. The general objective is to characterise and evaluate the coupled THMC processes in the near field and far field of a geological repository and to assess their impact on performance assessment: - during the three phases of repository development: excavation phase, operation phase and post-closure phase; - for three different rocks types: crystalline, argillaceous and tuff; - with specific focus on the issues of: Excavation Damaged Zone (EDZ), permanent property changes of rock masses, and glaciation and permafrost phenomena. The project involves a large number of research teams supported by radioactive waste management agencies or governmental regulatory bodies in Canada, China, Finland, France, Germany, Japan, Sweden and USA, who conducted advanced studies and numerical modelling of coupled THMC processes under five tasks. This report summarizes the work contributed to Phase 2 of Task B of the project, which took place during the period of March 2004 to May 2006. The Phase 2 work incorporated the use of a wide range of numerical models to simulate the failure of a number of intact rock core samples, from the APSE tunnel at Aespoe HRL, as tested in uniaxial compression and other loading conditions with the intention of establishing the common and code-specific features of the models. The core samples of the Aespoe diorite were treated with different initial mechanical and chemical conditions as dry samples, saturated with distilled water, formation water and saline water, with different durations of submersion, respectively, in order to observe the mechanical effects of saturation by different chemical fluids on the mechanical properties of the intact core

  7. Soil Moisture and Excavation Behaviour in the Chaco Leaf-Cutting Ant (Atta vollenweideri): Digging Performance and Prevention of Water Inflow into the Nest (United States)

    Pielström, Steffen; Roces, Flavio


    The Chaco leaf-cutting ant Atta vollenweideri is native to the clay-heavy soils of the Gran Chaco region in South America. Because of seasonal floods, colonies are regularly exposed to varying moisture across the soil profile, a factor that not only strongly influences workers' digging performance during nest building, but also determines the suitability of the soil for the rearing of the colony's symbiotic fungus. In this study, we investigated the effects of varying soil moisture on behaviours associated with underground nest building in A. vollenweideri. This was done in a series of laboratory experiments using standardised, plastic clay-water mixtures with gravimetric water contents ranging from relatively brittle material to mixtures close to the liquid limit. Our experiments showed that preference and group-level digging rate increased with increasing water content, but then dropped considerably for extremely moist materials. The production of vibrational recruitment signals during digging showed, on the contrary, a slightly negative linear correlation with soil moisture. Workers formed and carried clay pellets at higher rates in moist clay, even at the highest water content tested. Hence, their weak preference and low group-level excavation rate observed for that mixture cannot be explained by any inability to work with the material. More likely, extremely high moistures may indicate locations unsuitable for nest building. To test this hypothesis, we simulated a situation in which workers excavated an upward tunnel below accumulated surface water. The ants stopped digging about 12 mm below the interface soil/water, a behaviour representing a possible adaptation to the threat of water inflow field colonies are exposed to while digging under seasonally flooded soils. Possible roles of soil water in the temporal and spatial pattern of nest growth are discussed. PMID:24748382

  8. FREESURF: A three-dimensional finite-element model for simulating groundwater flow into and around an excavation

    Energy Technology Data Exchange (ETDEWEB)

    Weitzman, Morley


    A three-dimensional finite-element code was developed and used to simulate the flow of groundwater towards an excavation in a saturated porous medium, allowing for seepage faces. An iterative procedure was used to predict the movement of the water table and the seepage flux. The numerical solution agreed well with experimental results from a sandbox experiment. (auth)

  9. Assembling the Anthropocene: deep-time perspective on the development of a lithostratigraphic classification of Anthropogenic deposits and excavations (United States)

    Waters, C. N.; Ford, J. R.; Price, S.; Cooper, A. H.


    Human modification of the Earth's surface/subsurface is associated with artificial deposits (anthropogenic sedimentary units) and excavated ground (anthropogenic unconformities), analogous to ancient depositional systems. This study examines how artificial ground can be classified by the procedures used for natural deposits. Anthropogenic deposits have different characteristics to other parts of the stratigraphic column: 1) they vary greatly in lateral and vertical extent; 2) they are strictly allostratigraphic, i.e. defined and identified by bounding discontinuities, either unconformities (e.g. artificial deposits resting directly upon bedrock), disconformities (e.g. a time-gap between parallel artificial strata associated with non-deposition or reworking) or the present-day land surface; 3) many units have no overlying strata or bounding surface; 4) they are often poorly exposed, though associated landforms/geomorphology may show characteristic features that can aid definition. Artificial deposits comprise modified geologic materials, e.g. sand, clay, coal and novel anthropogenic materials, e.g. plastic, brick, glass. Such deposits are typically heterogeneous, the lithology determined for practical purposes by current/former landuse activity. BGS maps for the UK use a five-fold morpho-stratigraphic subdivision with no lithological attribution. An enhanced BGS scheme (Price et al. 2011) uses a three-tier hierarchy to describe the origin and landform of the deposit or excavation with lithology and age treated as additional attributes. Though based largely on geomorphlogical expression and genetic origin, the scheme can be used for classifying subsurface deposits lacking landform expression. Anthropogenic modification ('anthropoturbation') of rock and natural sediments, e.g. boreholes, tunnels and mineshafts, may extend to significant depths. Although indicating the extent of human influence they do not affect the classification of the stratigraphy; analogous to

  10. The five year report of the Tunnel Sealing Experiment: an international project of AECL, JNC, ANDRA and WIPP

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, N.A.; Cournut, A.; Dixon, D. (and others)


    The Tunnel Sealing Experiment (TSX) was conducted to address construction and performance issues of full-scale seals for potential application to deep geological repositories for radioactive waste. The TSX was performed by an international partnership representing Japan, France, the United States and Canada. The experiment was installed at the 420-m depth of Atomic Energy of Canada Limited's Underground Research Laboratory in the granite rock of the Precambrian Canadian Shield. The experiment involved the construction of two full-scale tunnel seals at either end of a single excavation. One seal was an assembly of pre-compacted sand-bentonite blocks and the second seal was a single cast of Low-Heat High-Performance concrete. The objective of the TSX was to assess the applicability of technologies for construction of practicable concrete and bentonite bulkheads; to evaluate the performance of each bulkhead; and to identify and document the parameters that affect that performance. This report documents the construction and operation of the experiment over its first five years. During this period, the experiment was designed, tunnels were excavated, and the seals were constructed. The sand-filled region between the two bulkhead seals was filled and pressurized with water to 800 and 2000 kPa. A tracer test was conducted at a tunnel pressure of 800 kPa to assess the solute transport characteristics of full-scale tunnel seals. The most important outcome from the TSX is that functional full-scale repository seals can be constructed using currently available technology. Factors identified as potentially affecting seal performance included: excavation method and minimizing the excavation damaged zone (EDZ); keying bulkheads into the rock to interrupt the EDZ; compacted sand-bentonite placement method; treatment of clay bulkhead-rock interface; rate of clay saturation compared with the rate of water pressurization; clay bulkhead volume expansion; the resealing properties

  11. A multi-method luminescence dating of the Palaeolithic sequence of La Ferrassie based on new excavations adjacent to the La Ferrassie 1 and 2 skeletons

    DEFF Research Database (Denmark)

    Guerin, Guillaume; Frouin, Marine; Talamo, Sahra


    A new interdisciplinary project was initiated to excavate a portion of the Palaeolithic site of La Ferrassie left intact by earlier excavations. One of the aims of this project was to provide chronological information on the succession of Middle and Upper Palaeolithic layers, as well as on the sk...


    Directory of Open Access Journals (Sweden)

    Zvonimir Deković


    Full Text Available The paper focuses on the features of the operation and maintenance of tunnels on the Zagreb-Macelj motorway. When it comes to the operation and maintenance of a series of six tunnels on the Zagreb-Macelj motorway, Sv. Tri Kralja Tunnel is the most challenging structure on the motorway, where it is necessary to provide an adequate level of safety and operability. Tunnel operation is ensured by the concession model of public - private partnership, which is applied to the Zagreb – Macelj motorway. Features of the tunnel infrastructure maintenance are emphasized, as well as importance of the extraordinary maintenance of the tunnel infrastructure. The goal of the tunnel operation and maintenance is to ensure undisturbed and safe traffic flow through the tunnels, by keeping the tunnel in normal functional conditions.

  13. Comparison of Management Oversight and Risk Tree and Tripod-Beta in Excavation Accident Analysis

    Directory of Open Access Journals (Sweden)



    Full Text Available Background Accident investigation programs are a necessary part in identification of risks and management of the business process. Objectives One of the most important features of such programs is the analysis technique for identifying the root causes of accidents in order to prevent their recurrences. Analytical Hierarchy Process (AHP was used to compare management oversight and risk tree (MORT with Tripod-Beta in order to determine the superior technique for analysis of fatal excavation accidents in construction industries. Materials and Methods MORT and Tripod-Beta techniques were used for analyzing two major accidents with three main steps. First, these techniques were applied to find out the causal factors of the accidents. Second, a number of criteria were developed for the comparison of the techniques and third, using AHP, the techniques were prioritized in terms of the criteria for choosing the superior one. Results The Tripod-Beta investigation showed 41 preconditions and 81 latent causes involved in the accidents. Additionally, 27 root causes of accidents were identified by the MORT analysis. Analytical hierarchy process (AHP investigation revealed that MORT had higher priorities only in two criteria than Tripod-Beta. Conclusions Our findings indicate that Tripod-Beta with a total priority of 0.664 is superior to MORT with the total priority of 0.33. It is recommended for future research to compare the available accident analysis techniques based on proper criteria to select the best for accident analysis.

  14. Percussive Excavation of Lunar Soil (United States)

    Whittaker, Matthew P.


    It has been suggested using a percussive motion could improve the efficiency of excavation by up to 90%. If this is proven to be true it would be very beneficial to excavation projects on the Moon and Mars. The purpose of this study is to design, build and test a percussive tool which could dig a trench and then compare this data against that of a non-percussive tool of the same shape and size. The results of this test thus far have been inconclusive due to malfunctions in the testbed and percussive bucket; however, experimental results from small scale experiments confirm this higher efficiency and support further testing.

  15. Particle and chemical control using tunnel flow (United States)

    Chilese, Frank; Delgado, Gildardo R.; Wack, Daniel; Torczynski, John R.


    An apparatus for contaminant control, having: a first optical assembly including: a first light homogenizer tunnel with: a first end connected to an extreme ultra-violet light source, a second end in communication with a destination chamber, a first enclosed space, and, a first gas input arranged to introduce a first gas such that the first gas flows in a first direction toward the first end and in a second direction toward the second end. The apparatus alternately having: a second optical assembly including: a second light homogenizer tunnel with: a third end connected to an extreme ultra-violet light source, a fourth end in communication with a destination chamber, a second enclosed space, a diffusion barrier tube including: a fifth end facing the fourth end and a sixth end in communication with a destination chamber, and a second gas input between the second light homogenizer tunnel and the diffusion tube.

  16. Great excavations refitting an existing tunnel ring at CERN for a new, more complex particle accelerator challenged designers to succeed under extraordinary conditions

    CERN Multimedia

    Wallis, S


    Caverns up to 35 m wide, 42 m high and 82 m long are now under construction at CERN to house the detectors which will be used for the LHC. The size and difficult geological conditions have made this a very challenging project (8 pages).

  17. Tunnel behaviour and support associated with the weak rock masses of flysch

    Directory of Open Access Journals (Sweden)

    V. Marinos


    Full Text Available Flysch formations are generally characterised by evident heterogeneity in the presence of low strength and tectonically disturbed structures. The complexity of these geological materials demands a more specialized geoengineering characterisation. In this regard, the paper tries to discuss the standardization of the engineering geological characteristics, the assessment of the behaviour in underground excavations, and the instructions–guidelines for the primary support measures for flysch layer qualitatively. In order to investigate the properties of flysch rock mass, 12 tunnels of Egnatia Highway, constructed in Northern Greece, were examined considering the data obtained from the design and construction records. Flysch formations are classified thereafter in 11 rock mass types (I–XI, according to the siltstone–sandstone proportion and their tectonic disturbance. A special geological strength index (GSI chart for heterogeneous rock masses is used and a range of geotechnical parameters for every flysch type is presented. Standardization tunnel behaviour for every rock mass type of flysch is also presented, based on its site-specific geotechnical characteristics such as structure, intact rock strength, persistence and complexity of discontinuities. Flysch, depending on its types, can be stable even under noticeable overburden depth, and exhibit wedge sliding and wider chimney type failures or cause serious deformation even under thin cover. Squeezing can be observed under high overburden depth. The magnitude of squeezing and tunnel support requirements are also discussed for various flysch rock mass types under different overburdens. Detailed principles and guidelines for selecting immediate support measures are proposed based on the principal tunnel behaviour mode and the experiences obtained from these 12 tunnels. Finally, the cost for tunnel support from these experiences is also presented.

  18. Tunnelling in Soft Soil : Tunnel Boring Machine Operation and Soil Response

    NARCIS (Netherlands)

    Festa, D.; Broere, W.; Bosch, J.W.

    Constructing tunnels in soft soil with the use of Tunnel Boring Machines may induce settlements including soil movements ahead of the face, soil relaxation into the tail void, possible heave due to grouting, long lasting consolidation processes, and potentially several other mechanisms. A

  19. Comparison between air and carbon dioxide insufflation in the endoscopic submucosal excavation of gastrointestinal stromal tumors. (United States)

    Shi, Wei-Bin; Wang, Zi-Hao; Qu, Chun-Ying; Zhang, Yi; Jiang, Han; Zhou, Min; Chen, Ying; Xu, Lei-Ming


    To evaluate the safety and efficacy of CO(2) insufflation compared with air insufflation in the endoscopic submucosal excavation (ESE) of gastrointestinal stromal tumors. Sixty patients were randomized to undergo endoscopic submucosal excavation, with the CO(2) group (n = 30) and the air group (n = 30) undergoing CO(2) insufflation and air insufflation in the ESE, respectively. The end-tidal CO(2) level (pETCO(2)) was observed at 4 time points: at the beginning of ESE, at total removal of the tumors, at completed wound management, and 10 min after ESE. Additionally, the patients' experience of pain at 1, 3, 6 and 24 h after the examination was registered using a visual analog scale (VAS). Both the CO(2) group and air group were similar in mean age, sex, body mass index (all P > 0.05). There were no significant differences in PetCO(2) values before and after the procedure (P > 0.05). However, the pain scores after the ESE at different time points in the CO(2) group decreased significantly compared with the air group (1 h: 21.2 ± 3.4 vs 61.5 ± 1.7; 3 h: 8.5 ± 0.7 vs 42.9 ± 1.3; 6 h: 4.4 ± 1.6 vs 27.6 ± 1.2; 24 h: 2.3 ± 0.4 vs 21.4 ± 0.7, P < 0.05). Meanwhile, the percentage of VAS scores of 0 in the CO(2) group after 1, 3, 6 and 24 h was significantly higher than that in the air group (60.7 ± 1.4 vs 18.9 ± 1.5, 81.5 ± 2.3 vs 20.6 ± 1.2, 89.2 ± 0.7 vs 36.8 ± 0.9, 91.3 ± 0.8 vs 63.8 ± 1.3, respectively, P < 0.05). Moreover, the condition of the CO(2) group was better than that of the air group with respect to anal exsufflation. Insufflation of CO(2) in the ESE of gastrointestinal stromal tumors will not cause CO(2) retention and it may significantly reduce the level of pain, thus it is safe and effective.

  20. Time in dissipative tunneling: Subtleties and applications (United States)

    Kelkar, N. G.; Lozano Gómez, D.; Patiño, Edgar J.


    Characteristic features of tunneling times for dissipative tunneling of a particle through a rectangular barrier are studied within a semiclassical model involving dissipation in the form of a velocity dependent frictional force. The average dwell time and traversal time with dissipation are found to be less than those without dissipation. This counter-intuitive behavior is reversed if one evaluates the physically relevant transmission dwell time. Apart from these observations, we find that the percentage of energy lost by the tunneling particle is higher for smaller energies. The above observations are tested and confirmed in a realistic case by applying the dissipation model to study the current-voltage data in a Al/Al2O3/Al solid state junction at various temperatures. The friction coefficient for Al2O3 as a function of temperature is presented. It is found to decrease with increasing temperature.

  1. Validation of a Compact Isokinetic Total Water Content Probe for Wind Tunnel Characterization at NASA Glenn Icing Research Tunnel and at NRC Ice Crystal Tunnel (United States)

    Davison, Craig R.; Landreville, Charles; Ratvasky, Thomas P.


    A new compact isokinetic probe to measure total water content in a wind tunnel environment has been developed. The probe has been previously tested under altitude conditions. This paper presents a comprehensive validation of the probe under a range of liquid water conditions at sea level in the NASA Glenn Icing Research Tunnel and with ice crystals at sea level at the NRC wind tunnel. The compact isokinetic probe is compared to tunnel calibrations and other probes.

  2. Overview of traffic safety aspects and design in road tunnels

    Directory of Open Access Journals (Sweden)

    Shy Bassan


    Drivers in road tunnels generally reduce their speed and increase their lateral position from the right tunnel wall while driving. In shorter tunnels, with reduced driving speed, driver vigilance may be more robust without being hindered by dull driving, which is more common in longer tunnels. Still, in spite of driver alertness, crash rates in tunnels occur due to the tunnel's unusual driving environment. Crash rates are lower in the tunnel inner zone due to driver alertness, especially after passing the transition zone and acclimating to the tunnel environment. The number of crashes, however, is higher along zone 4 (tunnel inner zone, which is the principal zone, as it covers longer driving distance. According to most studies, short tunnels were found to exhibit higher crash rates than long tunnels because the entrance zones incorporate higher crash rates, compared with the midzones; nonetheless, longer unidirectional (freeway and multilane tunnels with higher design speed, entail lower driver alertness and diminished concentration due to relatively monotonous driving in spite of a tunnel's closed environment.

  3. Iron Age Settlement at Blackstone, Worcestershire: Excavations 1972, 1973, and 1977

    Directory of Open Access Journals (Sweden)

    Derek Hurst


    Full Text Available Aerial photography in 1957 resulted in the discovery of a rectangular double-ditched enclosure overlooking the Severn floodplain near Bewdley, Worcestershire (UK. Excavation in the 1970s, in advance of gravel extraction, provided limited evidence of Mesolithic, Neolithic and Bronze Age activity prior to occupation in the later Iron Age, when the enclosure was established. This comprised a ditch and bank, and later a palisade and ditch, with single and double portal gateways respectively, and with buildings internally. Pottery and briquetage indicate trading links with the wider region, respectively with west and north Worcestershire, and with Droitwich. The main Iron Age occupation is dated from the 2nd century into the 1st century BC. By the 3rd-4th centuries AD the site was apparently cultivated, as small quantities of Romano-British pottery were scattered across it, probably as a result of manuring arable fields associated with a nearby, but as yet unlocated, settlement. Similarly, in the medieval and post-medieval periods a thin scatter of finds in the overlying soils indicated further agricultural activity. Unusually, the 1979 Iron Age site structural analysis has been largely retained in the current report without full revision but accompanied by a separate modern commentary, allied with the updated finds and environmental reporting, and overall discussion.

  4. Experiment to Characterize Aircraft Volatile Aerosol and Trace-Species Emissions (EXCAVATE) (United States)

    Anderson, B. E.; Branham, H.-S.; Hudgins, C. H.; Plant, J. V.; Ballenthin, J. O.; Miller, T. M.; Viggiano, A. A.; Blake, D. R.; Boudries, H.; Canagaratna, M.


    The Experiment to Characterize Aircraft Volatile and Trace Species Emissions (EXCAVATE) was conducted at Langley Research Center (LaRC) in January 2002 and focused upon assaying the production of aerosols and aerosol precursors by a modern commercial aircraft, the Langley B757, during ground-based operation. Remaining uncertainty in the postcombustion fate of jet fuel sulfur contaminants, the need for data to test new theories of particle formation and growth within engine exhaust plumes, and the need for observations to develop air quality models for predicting pollution levels in airport terminal areas were the primary factors motivating the experiment. NASA's Atmospheric Effects of Aviation Project (AEAP) and the Ultra Effect Engine Technology (UEET) Program sponsored the experiment which had the specific objectives of determining ion densities; the fraction of fuel S converted from S(IV) to S(VI); the concentration and speciation of volatile aerosols and black carbon; and gas-phase concentrations of long-chain hydrocarbon and PAH species, all as functions of engine power, fuel composition, and plume age.

  5. Assessment of technologies for hazardous waste site remediation: Non-treatment technologies and pilot scale facility implementation -- excavation -- storage technology -- safety analysis and review statement. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, H.R.; Overbey, W.K. Jr.; Koperna, G.J. Jr.


    The purpose of this study is to assess the state-of-the-art of excavation technology as related to environmental remediation applications. A further purpose is to determine which of the excavation technologies reviewed could be used by the US Corp of Engineers in remediating contaminated soil to be excavated in the near future for construction of a new Lock and Dam at Winfield, WV. The study is designed to identify excavation methodologies and equipment which can be used at any environmental remediation site but more specifically at the Winfield site on the Kanawha River in Putnam County, West Virginia. A technical approach was determined whereby a functional analysis was prepared to determine the functions to be conducted during the excavation phase of the remediation operations. A number of excavation technologies were identified from the literature. A set of screening criteria was developed that would examine the utility and ranking of the technologies with respect to the operations that needed to be conducted at the Winfield site. These criteria were performance, reliability, implementability, environmental safety, public health, and legal and regulatory compliance. The Loose Bulk excavation technology was ranked as the best technology applicable to the Winfield site. The literature was also examined to determine the success of various methods of controlling fugitive dust. Depending upon any changes in the results of chemical analyses, or prior remediation of the VOCs from the vadose zone, consideration should be given to testing a new ``Pneumatic Excavator`` which removes the VOCs liberated during the excavation process as they outgas from the soil. This equipment however would not be needed on locations with low levels of VOC emissions.

  6. Laboratory and field testing for utilization of an excavated soil as landfill liner material. (United States)

    Bozbey, Ilknur; Guler, Erol


    This study investigates the feasibility of using a silty soil excavated in highway construction as landfill liner material. The tests were conducted both at laboratory and in situ scales, and the soil was tested in pure and lime treated forms. Different levels of compaction energy were used. For the field study, a test pad was constructed and in situ hydraulic conductivity experiments were conducted by sealed double ring infiltrometers (SDRI). Laboratory testing revealed that while lime treatment improved the shear strength, it resulted in higher hydraulic conductivity values compared to pure soil. It was observed that leachate permeation did not change the hydraulic conductivity of the pure and lime treated samples. Laboratory hydraulic conductivities were on the order of 10(-9) m/s and met the 1.0E-08 m/s criterion in the Turkish regulations, which is one order of magnitude higher than the value allowed in most developed countries. SDRI testing, which lasted for 6 mo, indicated that lime treatment increased the hydraulic conductivity of pure soil significantly in the field scale tests. In situ hydraulic conductivities were on the order of 1E-08 and 1E-07 m/s, and exceeded the allowable value in the Turkish regulations. Undisturbed samples collected from the test pad were not representative of field hydraulic conductivities. Contrary to laboratory findings, higher compaction efforts did not result in lower hydraulic conductivities in field scales. The study verified the importance of in situ hydraulic conductivity testing in compacted liners.

  7. Impact of municipal wastewater effluent on seed bank response and soils excavated from a wetland impoundment (United States)

    Finocchiaro, R.G.; Kremer, R.J.; Fredrickson, L.H.


    Intensive management of wetlands to improve wildlife habitat typically includes the manipulation of water depth, duration, and timing to promote desired vegetation communities. Increased societal, industrial, and agricultural demands for water may encourage the use of alternative sources such as wastewater effluents in managed wetlands. However, water quality is commonly overlooked as an influence on wetland soil seed banks and soils. In four separate greenhouse trials conducted over a 2-yr period, we examined the effects of municipal wastewater effluent (WWE) on vegetation of wetland seed banks and soils excavated from a wildlife management area in Missouri, USA. We used microcosms filled with one of two soil materials and irrigated with WWE, Missouri River water, or deionized water to simulate moist-soil conditions. Vegetation that germinated from the soil seed bank was allowed to grow in microcosms for approximately 100 d. Vegetative taxa richness, plant density, and biomass were significantly reduced in WWE-irrigated soil materials compared with other water sources. Salinity and sodicity rapidly increased in WWE-irrigated microcosms and probably was responsible for inhibiting germination or interfering with seedling development. Our results indicate that irrigation with WWE promoted saline-sodic soil conditions, which alters the vegetation community by inhibiting germination or seedling development. ?? 2009, The Society of Wetland Scientists.

  8. Re-Excavation of Seti First Tomb, Kv17, Luxor, Egypt

    Directory of Open Access Journals (Sweden)

    Ayman HAMED


    Full Text Available This article is discussing technical challenges within engineering works made during re-excavation of the 174 m long tunnel which was cut into bedrock of desert shale known as 'Esna shale'. Recent historical events, during the last decade, explained much of the tunnel deformations and dirt filling inside tunnel space "Debris", caused by multiple water runoff attack to king's valley. The author is also discussing the challenging work under severe financial regime; using non conventional solutions adopted with extraordinary actions in using junk yard equipment. Seti I tomb, is considered as the deepest opening in the valley, not mentioning the risk in re-excavation the tomb, harsh atmospheric conditions inside the tunnel, measured and monitored by author, needed a serious ventilation system to serve workers during removal of dirt. Through that, an interesting mathematical relation between atmospheric variables has been emphasized. Design of steel supporting system serving an inclined deep tunnel with irregular circumference, under strict condition of reversibility, has been performed as a remarkable topic, to solve and apply in such archaeological site. Finally, the article is considered as a scientific pattern for application of geo-engineering in conservation of underground archaeological sites.

  9. Excavations of Islamic Jarash, 2002-2005

    DEFF Research Database (Denmark)

    Walmsley, Alan George


    A preliminary report on the excavations at Jarash's mosque by the Danish-Jordanian Islamic Jarash Project during four seasons between 2002 and 2005.......A preliminary report on the excavations at Jarash's mosque by the Danish-Jordanian Islamic Jarash Project during four seasons between 2002 and 2005....

  10. Rock mass characterization for tunnels in the Copenhagen limestone

    DEFF Research Database (Denmark)

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


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

  11. Shape and Reinforcement Optimization of Underground Tunnels (United States)

    Ghabraie, Kazem; Xie, Yi Min; Huang, Xiaodong; Ren, Gang

    Design of support system and selecting an optimum shape for the opening are two important steps in designing excavations in rock masses. Currently selecting the shape and support design are mainly based on designer's judgment and experience. Both of these problems can be viewed as material distribution problems where one needs to find the optimum distribution of a material in a domain. Topology optimization techniques have proved to be useful in solving these kinds of problems in structural design. Recently the application of topology optimization techniques in reinforcement design around underground excavations has been studied by some researchers. In this paper a three-phase material model will be introduced changing between normal rock, reinforced rock, and void. Using such a material model both problems of shape and reinforcement design can be solved together. A well-known topology optimization technique used in structural design is bi-directional evolutionary structural optimization (BESO). In this paper the BESO technique has been extended to simultaneously optimize the shape of the opening and the distribution of reinforcements. Validity and capability of the proposed approach have been investigated through some examples.

  12. Archaeology Excavation Simulation: Correcting the Emphasis (United States)

    Thistle, Paul C.


    Museums offering archaeological programs often attempt to use the "sandbox approach" to simulate archaeological excavation work. However, in light of the definition of simulation, and given the realities of actual professional practice in archaeological excavation, the author argues that the activity of troweling for artifacts in loose sand places…

  13. Modeling of excavation induced coupled hydraulic-mechanical processes in claystone

    Energy Technology Data Exchange (ETDEWEB)

    Massmann, Jobst


    Concepts for the numerical modeling of excavation induced processes in claystone are investigated. The study has been motivated by the international discussion on the adequacy of claystone as a potential host rock for a final repository of radioactive waste. The processes, which could impact the safety of such a repository, are manifold and strongly interacting. Thus, a multiphysics approach is needed, regarding solid mechanics and fluid mechanics within a geological context. A coupled modeling concept is therefore indispensable. Based on observations and measurements at an argillaceous test site (the underground laboratory Tournemire, operated by the Institute of Radioprotection and Nuclear Safety, France) the modeling concept is developed. Two main processes constitute the basis of the applied model: deformation (linear elasticity considering damage) and fluid flow (unsaturated one-phase flow). Several coupling phenomena are considered: Terzaghi 's effective stress concept, mass conservation of the liquid in a deformable porous media, drying induced shrinkage, and a permeability which depends on deformation and damage. In addition, transversely isotropic material behavior is considered. The numerical simulations are done with the finite element code RockFlow, which is extended to include: an orthotropic non-linear shrinkage model, a continuum damage model, and an orthotropic permeability model. For these new methods the theory and a literature review are presented, followed by applications, which illustrate the capability to model excavation induced processes in principle. In a comprehensive case study, the modeling concept is used to simulate the response of the Tournemire argillite to excavation. The results are compared with observations and measurements of three different excavations (century old tunnel, two galleries excavated in 1996 and 2003). In summary, it can be concluded that the developed model concept provides a prediction of the excavation

  14. Tunneling times and the Hartman effect revisited

    Energy Technology Data Exchange (ETDEWEB)

    Olkhovsky, Vladislav S. [Ukrainian Academy of Sciences, Kiev (Ukraine). Inst. for Nuclear Research]|[Istituto Nazionale di Fisica Nucleare, Catania (Italy); Recami, Erasmo [Universidade Estadual de Campinas, SP (Brazil). Dept. de Matematica Aplicada]|[Istituto Nazionale di Fisica Nucleare, Milano (Italy); Raciti, Fabio [Catania Univ. (Italy). Dipt. di Fisica; Zaichenko, Aleksandr K. [Ukrainian Academy of Sciences, Kiev (Ukraine)


    In a recent review paper we proposed, within conventional quantum mechanics, new definitions for the sub-barrier tunnelling and reflection times. Aims of the present paper are: presenting and analysing the results of various numerical calculations (based on our equations) on the penetration and return times < {tau}Pen >, <{tau}Ret >, during tunneling inside a rectangular potential barrier, for various penetration depths x{sub f}; putting forth and discussing suitable definitions, besides of the mean values, also of the variances (or dispersions) D {sup {tau}}T D {sup {tau}}R for the time durations of transmission and reflection process; mentioning that our definition < {sup {tau}}T > for the average transmission time results to constitute an improvement of the ordinary dwell-time {tau}{sup Dw} formula; commenting upon some recent criticism by C.R. Leavens, on the basis of our new numerical results. We stress that our numerical evaluations confirm that our approach implied and implies, the existence of the Hartman effect: an effect that in these days (due to the theoretical connections between tunneling and evanescent wave propagation) is receiving - at Cologne, Berkeley, Florence and Vienna- indirect, but quite interesting, experimental verifications. At last, we briefly analyze some other definitions of tunnelling times. (author). 24 refs., 5 figs.

  15. Explosion risks and consequences for tunnels

    NARCIS (Netherlands)

    Weerheijm, J.; Berg, A.C. van den


    Tunnel accidents with transports of dangerous goods may lead to explosions. Risk assessment for these accidents is complicated because of the low probability and the unknown, but disastrous effects expected. Especially the lack of knowledge on the strength of the explosion and the consequences for

  16. 46 CFR 171.100 - Shaft tunnels and stern tubes. (United States)


    ... 46 Shipping 7 2010-10-01 2010-10-01 false Shaft tunnels and stern tubes. 171.100 Section 171.100... PERTAINING TO VESSELS CARRYING PASSENGERS Additional Subdivision Requirements § 171.100 Shaft tunnels and... and the machinery space must be located in a watertight shaft tunnel. The vessel must be designed so...

  17. Design, production and initial state of the backfill and plug in deposition tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Boerjesson, Lennart; Gunnarsson, David; Johannesson, Lars-Erik; Jonsson, Esther


    The report is included in a set of Production reports, presenting how the KBS-3 repository is designed, produced and inspected. The set of reports is included in the safety report for the KBS-3 repository and repository facility. The report provides input on the initial state of the backfill and plug in deposition tunnels for the assessment of the long-term safety, SR-Site. The initial state refers to the properties of the engineered barriers once they have been finally placed in the KBS-3 repository and will not be further handled within the repository facility. In addition, the report provides input to the operational safety report, SR-Operation, on how the backfill and plug shall be handled and installed. The report presents the design premises and reference designs of the backfill and plug in deposition tunnels and verifies their conformity to the design premises. It also describes the production of the backfill from excavation and delivery of backfill material to installation in the deposition tunnel, and gives an outline of the installation of the plug. Finally, the initial states of the backfill and plug and their conformity to the reference designs and design premises are presented

  18. Probing the surface chemistry of polycrystalline ZnO with scanning tunneling microscopy and tunneling spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rohrer, G.S.; Bonnell, D.A. (Univ. of Pennsylvania, Philadelphia (United States))

    This paper describes the use of scanning tunneling microscopy and spatially resolved tunneling spectroscopy to examine polycrystalline ZnO surface in ultrahigh vacuum after bake-out, after a low temperature anneal that cleaned the surface, after a high temperature anneal, which segregated bismuth to the surface, after being dosed with O{sub 2} and H{sub 2}O, and after exposure to air. The tunneling spectra depend both on the proximity to structural features, such as grain boundaries, and on the chemical composition of the surface. For example, the segregation of bismuth to the surface causes the tunneling spectra to have a p-type rectification. Our results also indicate that the rectification of tunneling spectra acquired in air is caused by surface hydration and that images of surfaces that have not been heated in vacuum have inferior resolution due to a reduction in the height of the apparent tunnel barrier. Spatially resolved tunneling spectroscopy has been used to demonstrate that surface hydration has a greater effect on the crystallite surfaces than on the grain boundary surfaces.

  19. The Discovery and Excavation of a Human Burial from the Mini-athiliya Shell Midden in Southern Sri Lanka

    Directory of Open Access Journals (Sweden)

    Samanti Kulatilake


    Full Text Available Several shell middens of coastal Sri Lanka indicate human occupation in the mid-Holocene and are recognized as being of prime importance in the archaeological narrative of the island. A salvage archaeology operation conducted at the Mini-athiliya shell midden in the Southern Province of Sri Lanka, yielded ancient human remains associated with stone implements and culturally modified faunal remains. The main objective of this rescue operation was to mitigate the destruction to this archaeological site. We report the excavation strategy and dating of this mid-Holocene shell midden, while focusing on the discovery and extraction of a complete human burial that had not been disturbed by the shell mining activity at the site. This excavation is intended to serve as a precursor to systematic investigation of the coastal shell middens of southern Sri Lanka.

  20. Fractionation of Pb and Cu in the fine fraction (<10 mm) of waste excavated from a municipal landfill. (United States)

    Kaczala, Fabio; Orupõld, Kaja; Augustsson, Anna; Burlakovs, Juris; Hogland, Marika; Bhatnagar, Amit; Hogland, William


    The fractionation of metals in the fine fraction (circular economy and recovery of such valuables back into the economy. To conclude, not only the total concentration of metals but also a better understanding of fractionation and in which form metals are bound is very important to bring information on how to manage the fine fraction from excavated waste both in terms of environmental impacts and also recovery of such valuables in the economy.

  1. Using Local Second Gradient Model and Shear Strain Localisation to Model the Excavation Damaged Zone in Unsaturated Claystone (United States)

    Pardoen, Benoît; Levasseur, Séverine; Collin, Frédéric


    The drilling of galleries induces damage propagation in the surrounding medium and creates, around them, the excavation damaged zone (EDZ). The prediction of the extension and fracture structure of this zone remains a major issue, especially in the context of underground nuclear waste storage. Experimental studies on geomaterials indicate that localised deformation in shear band mode usually appears prior to fractures. Thus, the excavation damaged zone can be modelled by considering the development of shear strain localisation bands. In the classical finite element framework, strain localisation suffers a mesh-dependency problem. Therefore, an enhanced model with a regularisation method is required to correctly model the strain localisation behaviour. Among the existing methods, we choose the coupled local second gradient model. We extend it to unsaturated conditions and we include the solid grain compressibility. Furthermore, air ventilation inside underground galleries engenders a rock-atmosphere interaction that could influence the damaged zone. This interaction has to be investigated in order to predict the damaged zone behaviour. Finally, a hydro-mechanical modelling of a gallery excavation in claystone is presented and leads to a fairly good representation of the EDZ. The main objectives of this study are to model the fractures by considering shear strain localisation bands, and to investigate if an isotropic model accurately reproduces the in situ measurements. The numerical results provide information about the damaged zone extension, structure and behaviour that are in very good agreement with in situ measurements and observations. For instance, the strain localisation bands that develop in chevron pattern during the excavation and rock desaturation, due to air ventilation, are observed close to the gallery.

  2. MPED: An ISRU Bucket Ladder Excavator Demonstrator System Project (United States)

    National Aeronautics and Space Administration — Abstract: The Multi-Purpose Excavation Demonstrator (MPED) is a commercial effort and a third generation of technology, following Bucket Wheel Excavator and Bucket...

  3. Structural monitoring of metro infrastructure during shield tunneling construction. (United States)

    Ran, L; Ye, X W; Ming, G; Dong, X B


    Shield tunneling construction of metro infrastructure will continuously disturb the soils. The ground surface will be subjected to uplift or subsidence due to the deep excavation and the extrusion and consolidation of the soils. Implementation of the simultaneous monitoring with the shield tunnel construction will provide an effective reference in controlling the shield driving, while how to design and implement a safe, economic, and effective structural monitoring system for metro infrastructure is of great importance and necessity. This paper presents the general architecture of the shield construction of metro tunnels as well as the procedure of the artificial ground freezing construction of the metro-tunnel cross-passages. The design principles for metro infrastructure monitoring of the shield tunnel intervals in the Hangzhou Metro Line 1 are introduced. The detailed monitoring items and the specified alarming indices for construction monitoring of the shield tunneling are addressed, and the measured settlement variations at different monitoring locations are also presented.

  4. Structural Monitoring of Metro Infrastructure during Shield Tunneling Construction

    Directory of Open Access Journals (Sweden)

    L. Ran


    Full Text Available Shield tunneling construction of metro infrastructure will continuously disturb the soils. The ground surface will be subjected to uplift or subsidence due to the deep excavation and the extrusion and consolidation of the soils. Implementation of the simultaneous monitoring with the shield tunnel construction will provide an effective reference in controlling the shield driving, while how to design and implement a safe, economic, and effective structural monitoring system for metro infrastructure is of great importance and necessity. This paper presents the general architecture of the shield construction of metro tunnels as well as the procedure of the artificial ground freezing construction of the metro-tunnel cross-passages. The design principles for metro infrastructure monitoring of the shield tunnel intervals in the Hangzhou Metro Line 1 are introduced. The detailed monitoring items and the specified alarming indices for construction monitoring of the shield tunneling are addressed, and the measured settlement variations at different monitoring locations are also presented.

  5. Excavating abiotic stress-related gene resources of terrestrial macroscopic cyanobacteria for crop genetic engineering: dawn and challenge. (United States)

    Ye, Shuifeng; Gao, Xiang


    Genetically engineered (GE) crops with resistance to environmental stresses are one of the most important solutions for future food security. Numerous genes associated to plant stress resistance have been identified and characterized. However, the current reality is that only a few transgenic crops expressing prokaryotic genes are successfully applied in field conditions. These few prokaryotic genes include Agrobacterium strain CP4 EPSPS gene, Bacillus thuringiensis Cry1Ab gene and a bacterial chaperonin gene. Thus, the excavation of potentially critical genes still remains an arduous task for crop engineering. Terrestrial macroscopic cyanobacteria, Nostoc commune and Nostoc flagelliforme, which exhibit extreme resistance to desiccation stress, may serve as new prokaryotic bioresources for excavating critical genes. Recently, their marker gene wspA was heterologously expressed in Arabidopsis plant and the transgenics exhibited more flourishing root systems than wild-type plants under osmotic stress condition. In addition, some new genes associated with drought response and adaptation in N. flagelliforme are being uncovered by our ongoing RNA-seq analysis. Although the relevant work about the terrestrial macroscopic cyanobacteria is still underway, we believe that the prospect of excavating their critical genes for application in GE crops is quite optimistic.

  6. Middle Stone Age stratigraphy and excavations at Die Kelders Cave 1 (Western Cape Province, South Africa): the 1992, 1993, and 1995 field seasons. (United States)

    Marean, C W; Goldberg, P; Avery, G; Grine, F E; Klein, R G


    Die Kelders Cave 1, first excavated under the direction of Franz Schweitzer in 1969-1973, was re-excavated between 1992 and 1995 by a combined team from the South African Museum, SUNY at Stony Brook, and Stanford University. These renewed excavations enlarged the artefactual and faunal samples from the inadequately sampled and less intensively excavated lower Middle Stone Age (MSA) layers, increased our understanding of the complex site formation processes within the cave, enlarged the hominid sample from the MSA deposits, and generated ESR, TL, and OSL dates for the MSA layers. Importantly, these new excavations dramatically improved our comprehension of the vertical and lateral characteristics of the MSA stratigraphy. Surface plotting of the MSA layers has led to the identification of at least two major zones of subsidence that significantly warped the layers, draping some along the eroding surface contours of major blocks of fallen limestone roof rock. A third zone of subsidence is probably present in the older excavations. Dramatic roof falls of very large limestone blocks occurred at least twice-once in the middle of Layer 4/5 where the roof blocks were only slightly weathered after collapse, and at the top of Layer 6 where the blocks weathered heavily after collapse, producing a zone of decomposed rock around the blocks. Many of the sandy strata are cut by small and localized faults and slippages. All of the strata documented by Schweitzer's excavations are present throughout the exposed area to the west of his excavated area, where many of them thicken and become more complex. Layer 6, the thickest MSA layer, becomes less diagenetically altered and compressed to the west. Copyright 2000 Academic Press.

  7. Mutual seismic interaction between tunnels and the surrounding granular soil

    Directory of Open Access Journals (Sweden)

    Mohamed Ahmed Abdel-Motaal


    Study results show that the maximum exerted straining actions in tunnel lining are directly proportional to the relative stiffness between tunnel and surrounding soil (lining thickness and soil shear modulus. Moreover, it is highly affected by the peak ground acceleration and the tunnel location (embedment depth. A comprehensive study is performed to show the effect of tunnel thickness and tunnel diameter on both the induced bending moment and lining deformation. In general, it is concluded that seismic analysis should be considered in regions subjected to peak ground acceleration greater than 0.15g.

  8. Key technologies and risk management of deep tunnel construction at Jinping II hydropower station

    Directory of Open Access Journals (Sweden)

    Chunsheng Zhang


    Full Text Available The four diversion tunnels at Jinping II hydropower station represent the deepest underground project yet conducted in China, with an overburden depth of 1500–2000 m and a maximum depth of 2525 m. The tunnel structure was subjected to a maximum external water pressure of 10.22 MPa and the maximum single-point groundwater inflow of 7.3 m3/s. The success of the project construction was related to numerous challenging issues such as the stability of the rock mass surrounding the deep tunnels, strong rockburst prevention and control, and the treatment of high-pressure, large-volume groundwater infiltration. During the construction period, a series of new technologies was developed for the purpose of risk control in the deep tunnel project. Nondestructive sampling and in-situ measurement technologies were employed to fully characterize the formation and development of excavation damaged zones (EDZs, and to evaluate the mechanical behaviors of deep rocks. The time effect of marble fracture propagation, the brittle–ductile–plastic transition of marble, and the temporal development of rock mass fracture and damage induced by high geostress were characterized. The safe construction of deep tunnels was achieved under a high risk of strong rockburst using active measures, a support system comprised of lining, grouting, and external water pressure reduction techniques that addressed the coupled effect of high geostress, high external water pressure, and a comprehensive early-warning system. A complete set of technologies for the treatment of high-pressure and large-volume groundwater infiltration was developed. Monitoring results indicated that the Jinping II hydropower station has been generally stable since it was put into operation in 2014.

  9. 40 CFR Table F-2 to Subpart F of... - Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and... (United States)


    ... Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test F Table F-2 to Subpart F... Part 53—Particle Sizes and Wind Speeds for Full Wind Tunnel Test, Wind Tunnel Inlet Aspiration Test, and Static Chamber Test Primary Partical Mean Size a (µm) Full Wind Tunnel Test 2 km/hr 24 km/hr Inlet...

  10. Excavation and drying of compressed peat; Tiivistetyn turpeen nosto ja kuivaus

    Energy Technology Data Exchange (ETDEWEB)

    Erkkilae, A.; Frilander, P.; Hillebrand, K.; Nurmi, H.


    The target of this three year (1993 - 1995) project was to improve the peat product-ion efficiency by developing an energy economical excavation method for compressed peat, by which it is possible to obtain best possible degree of compression and load from the DS-production point of view. It is possible to improve the degree of utilization of solar radiation in drying from 30 % to 40 %. The main research areas were drying of the compressed peat and peat compression. The third sub-task for 1995 was demonstration of the main parts of the method in laboratory scale. Experimental compressed peat (Compeat) drying models were made for peats Carex-peat H7, Carex-peat H5 and Carex-Sphagnum-peat H7. Compeat dried without turning in best circumstances in 34 % shorter time than milled layer made of the same peat turned twice, the initial moisture content being 4 kgH2OkgDS-1. In the tests carried out in 1995 with Carex-peat the compression had not corresponding effect on intensifying of the drying of peat. Compression of Carex-Sphagnum peat H7 increased the drying speed by about 10 % compared with the drying time of uncompressed milled layer. In the sprinkling test about 30-50 % of the sprinkled water was sucked into the compressed peat layer, while about 70 % of the rain is sucked into the corresponding uncompressed milled layer. Use of vibration decreased the energy consumption of the steel-surfaced nozzles about 20 % in the maximum, but the effect depend on the rotation speed of the macerator and the vibration power. In the new Compeat method (production method for compressed peat), developed in the research, the peat is loosened from the field surface by milling 3-5 cm thick layer of peat of moisture content 75-80 %

  11. Deriving a Planting Medium from Solid Waste Compost and Construction, Demolition and Excavation Waste (United States)

    Farajalla, Nadim; Assaf, Eleni; Bashour, Issam; Talhouk, Salma


    Lebanon's very high population density has been increasing since the end of the war in the early 1990s reaching 416.36 people per square kilometer. Furthermore, the influx of refugees from conflicts in the region has increased the resident population significantly. All these are exerting pressure on the country's natural resources, pushing the Lebanese to convert more forest and agricultural land into roads, buildings and houses. This has led to a building boom and rapid urbanization which in turn has created a demand for construction material - mainly rock, gravel, sand, etc. nearly all of which were locally acquired through quarrying to the tune of three million cubic meters annually. This boom has been followed by a war with Israel in 2006 which resulted in thousands of tonnes of debris. The increase in population has also led to an increase in solid waste generation with 1.57 million tonnes of solid waste generated in Lebanon per year. The combination of construction, demolition and excavation (CDE) waste along with the increase in solid waste generation has put a major stress on the country and on the management of its solid waste problem. Compounding this problem are the issues of quarries closure and rehabilitation and a decrease in forest and vegetative cover. The on-going research reported in this paper aims to provide an integrated solution to the stated problem by developing a "soil mix" derived from a mélange of the organic matter of the solid waste (compost), the CDE waste, and soil. In this mix, native and indicator plants are planted (in pots) from which the most productive mix will be selected for further testing at field level in later experiments. The plant species used are Matiolla, a native Lebanese plant and Zea mays, which is commonly known used as an indicator plant due to its sensitivity to environmental conditions. To ensure sustainability and environmental friendliness of the mix, its physical and chemical characteristics are monitored

  12. Measuring radon flux across active faults: Relevance of excavating and possibility of satellite discharges

    Energy Technology Data Exchange (ETDEWEB)

    Richon, Patrick, E-mail: patrick.richon@cea.f [CEA, DAM, DIF, F-91297 Arpajon (France); Institut de Physique du Globe de Paris, Equipe Geologie des Systemes Volcaniques, 4 place Jussieu, UMR-7154 CNRS, F-75005 Paris (France); Klinger, Yann; Tapponnier, Paul [Institut de Physique du Globe de Paris, Equipe de Seismotectonique, 4 place Jussieu, UMR-7154 CNRS, F-75005 Paris (France); Li Chenxia [Institute of Geology, Chinese Earthquake Administration, P.O. Box 9803, 100029 Beijing (China); Van Der Woerd, Jerome [Institut de Physique du Globe de Strasbourg, CNRS, UMR-7516, INSU, Universite Louis Pasteur, Strasbourg I, 5 Rue Rene Descartes, F-67084 Strasbourg Cedex (France); Perrier, Frederic [Institut de Physique du Globe de Paris, Equipe de Geomagnetisme, 4 place Jussieu, UMR-7154 CNRS et Universite Paris 7 Denis-Diderot, F-75005 Paris (France)


    Searching for gas exhalation around major tectonic contacts raises important methodological issues such as the role of the superficial soil and the possible long distance transport. These effects have been studied on the Xidatan segment of the Kunlun Fault, Qinghai Province, China, using measurement of the radon-222 and carbon dioxide exhalation flux. A significant radon flux, reaching up to 538 +- 33 mBq m{sup -2} s{sup -1} was observed in a 2-3 m deep trench excavated across the fault. On the soil surface, the radon flux varied from 7 to 38 mBq m{sup -2} s{sup -1}, including on the fault trace, with an average value of 14.1 +- 1.0 mBq m{sup -2} s{sup -1}, similar to the world average. The carbon dioxide flux on the soil surface, with an average value of 12.9 +- 3.3 g m{sup -2} day{sup -1}, also remained similar to regular background values. It showed no systematic spatial variation up to a distance of 1 km from the fault, and no clear enhancement in the trench. However, a high carbon dioxide flux of 421 +- 130 g m{sup -2} day{sup -1} was observed near subvertical fractured phyllite outcrops on a hill located about 3 km north of the fault, at the boundary of the large-scale pull-apart basin associated with the fault. This high carbon dioxide flux was associated with a high radon flux of 607 +- 35 mBq m{sup -2} s{sup -1}. These preliminary results indicate that, at the fault trace, it can be important to measure gas flux at the bottom of a trench to remove superficial soil layers. In addition, gas discharges need to be investigated also at some distance from the main fault, in zones where morphotectonics features support associated secondary fractures.

  13. Drip Sealing Grouting of Tunnels in Crystalline Rock: Conceptualisation and Technical Strategies

    Energy Technology Data Exchange (ETDEWEB)

    Butron, Christian


    A conceptual model of the groundwater hydraulic conditions around the tunnel contour in ancient brittle crystalline rocks has been developed and verified. The general aim has been to reach an understanding of the groundwater conditions in and close to the tunnel roof where dripping takes place and to propose technical and practical strategies for waterproofing. Dripping is accompanied by ice growth and icicle formation in cold regions, creating additional problems such as shotcrete fall-outs, icicle fall-outs, damage to vehicles, damage to trains, etc. The methodology for the development of the conceptual model is based mainly on transmissivity determinations from short-duration hydraulic tests and analyses of the connectivity of the fracture structure by means of semi-variogram analysis. The determination of the dimensionality of the flow in the fractures has also been found to be essential in order to describe the conductive system. This conceptual model describes the fracture systems as a combination of transmissive patches (2D-flow fractures) connected by less pervious channels (1D-flow fractures). It provides an understanding of the heterogeneity and connectivity of the fracture network and thus the groundwater conditions, not only in the roof but also around the tunnel contour. The pre-excavation grouting design process used in the tunnelling projects followed a structured approach and the evaluation showed that the grouting design reduced the inflow and fulfilled the environmental demands. However, dripping remained, making its characterisation very important when proposing a possible solution for its control. It is proposed that the remaining dripping comes from a channelised system that has been left unsealed and which would be extremely difficult to intersect with future boreholes, as well as from some ungrouted fractures with inconvenient orientations. Geomembrane lining and post-excavation grouting are possible solutions, although particular attention

  14. Silicon-germanium nanowire tunnel-FETs with homo- and heterostructure tunnel junctions (United States)

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


    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.

  15. High non-anatomic tunnel position rates in ACL reconstruction failure using both transtibial and anteromedial tunnel drilling techniques. (United States)

    Jaecker, Vera; Zapf, Tabea; Naendrup, Jan-Hendrik; Pfeiffer, Thomas; Kanakamedala, Ajay C; Wafaisade, Arasch; Shafizadeh, Sven


    Although it is well known from cadaveric and biomechanical studies that transtibial femoral tunnel (TT) positioning techniques are associated with non-anatomic tunnel positions, controversial data exist as so far no clinical differences could have been found, comparing transtibial with anteromedial techniques (AM). The purpose of the study was to analyze if graft failure following TT ACL reconstruction was more commonly associated with non-anatomic tunnel position in comparison with the AM technique. We hypothesized that, compared to AM techniques, non-anatomic tunnel positions correlate with TT tunnel positioning techniques. A total of 147 cases of ACL revision surgery were analyzed retrospectively. Primary ACL reconstructions were analyzed regarding the femoral tunnel drilling technique. Femoral and tibial tunnel positions were determined on CT scans using validated radiographic measurement methods. Correlation analysis was performed to determine differences between TT and AM techniques. A total of 101 cases were included, of whom 64 (63.4%) underwent the TT technique and 37 (36.6%) the AM technique for primary ACL reconstruction. Non-anatomic femoral tunnel positions were found in 77.2% and non-anatomical tibial tunnel positions in 40.1%. No correlations were found comparing tunnel positions in TT and AM techniques, revealing non-anatomic femoral tunnel positions in 79.7 and 73% and non-anatomic tibial tunnel positions in 43.7 and 35.1%, respectively (p > 0.05). Considerable rates of non-anatomic femoral and tibial tunnel positions were found in ACL revisions with both transtibial and anteromedial femoral drilling techniques. Despite the potential of placing tunnels more anatomically using an additional AM portal, this technique does not ensure anatomic tunnel positioning. Consequently, the data highlight the importance of anatomic tunnel positioning in primary ACL reconstruction, regardless of the applied drilling technique.

  16. Scanning tunneling microscope assembly, reactor, and system (United States)

    Tao, Feng; Salmeron, Miquel; Somorjai, Gabor A


    An embodiment of a scanning tunneling microscope (STM) reactor includes a pressure vessel, an STM assembly, and three spring coupling objects. The pressure vessel includes a sealable port, an interior, and an exterior. An embodiment of an STM system includes a vacuum chamber, an STM reactor, and three springs. The three springs couple the STM reactor to the vacuum chamber and are operable to suspend the scanning tunneling microscope reactor within the interior of the vacuum chamber during operation of the STM reactor. An embodiment of an STM assembly includes a coarse displacement arrangement, a piezoelectric fine displacement scanning tube coupled to the coarse displacement arrangement, and a receiver. The piezoelectric fine displacement scanning tube is coupled to the coarse displacement arrangement. The receiver is coupled to the piezoelectric scanning tube and is operable to receive a tip holder, and the tip holder is operable to receive a tip.

  17. Structural and tunneling properties of Si nanowires

    KAUST Repository

    Montes Muñoz, Enrique


    We investigate the electronic structure and electron transport properties of Si nanowires attached to Au electrodes from first principles using density functional theory and the nonequilibrium Green\\'s function method. We systematically study the dependence of the transport properties on the diameter of the nanowires, on the growth direction, and on the length. At the equilibrium Au-nanowire distance we find strong electronic coupling between the electrodes and nanowires, which results in a low contact resistance. With increasing nanowire length we study the transition from metallic to tunneling conductance for small applied bias. For the tunneling regime we investigate the decay of the conductance with the nanowire length and rationalize the results using the complex band structure of the pristine nanowires. The conductance is found to depend strongly on the growth direction, with nanowires grown along the ⟨110⟩ direction showing the smallest decay with length and the largest conductance and current.

  18. 29 CFR 1926.651 - Specific excavation requirements. (United States)


    ... 29 Labor 8 2010-07-01 2010-07-01 false Specific excavation requirements. 1926.651 Section 1926.651..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Excavations § 1926.651 Specific excavation requirements. (a) Surface encumbrances. All surface encumbrances that are located so as...

  19. In vivo assessment of caries excavation with a fluorescence camera compared to direct bacteriological sampling and quantitative analysis using flow cytometry. (United States)

    Stoll, Richard; Urban-Klein, Beata; Giacomin, Paul; Loukas, Alex; Jablonski-Momeni, Anahita


    The aim of this study was to assess the performance of the fluorescence camera device VistaCam iX (VC) for the control of caries excavation compared to visual assessment and bacteriological evaluation. Twenty-three patients with 32 dentinal carious lesions were included in the study. The lesions were classified using the International Caries Detection and Assessment System. Fluorescence images were taken at the surface of each lesion using the VC before excavation (stage 1), during (stage 2) and after excavation (stage 3). At each stage, dentine samples were collected. All cavities were closed after excavation using permanent fillings. Bacteria were counted within each dentine sample using flow cytometry. Significant moderate correlation between the fluorescence readings and the bacteria count was found at stage 3 (Spearman correlation coefficient rs = 0.40, p = 0.027). Area under the ROC curve (AUC) was calculated for fluorescence readings and bacteria count using the clinical status at stage 3 as a reference. AUC was 0.954 for the VC readings and 0.797 for bacteria count. Using the median bacteria count at stage 3 as a reference, the AUC for the fluorescence readings was 0.753. The results indicate that the fluorescence camera appears to be a useful supplementary tool in assessing the endpoint of caries excavation with the advantage of enabling data to be digitally visualized and stored. When an experienced dental clinician determined the excavation endpoint, the performance with respect to remaining bacteria count was good.

  20. Evaluation of tunnel seismic prediction (TSP) result using the Japanese highway rock mass classification system for Pahang-Selangor Raw Water Transfer Tunnel (United States)

    Von, W. C.; Ismail, M. A. M.


    The knowing of geological profile ahead of tunnel face is significant to minimize the risk in tunnel excavation work and cost control in preventative measure. Due to mountainous area, site investigation with vertical boring is not recommended to obtain the geological profile for Pahang-Selangor Raw Water Transfer project. Hence, tunnel seismic prediction (TSP) method is adopted to predict the geological profile ahead of tunnel face. In order to evaluate the TSP results, IBM SPSS Statistic 22 is used to run artificial neural network (ANN) analysis to back calculate the predicted Rock Grade Points (JH) from actual Rock Grade Points (JH) using Vp, Vs and Vp/Vs from TSP. The results show good correlation between predicted Rock Grade points and actual Rock Grade Points (JH). In other words, TSP can provide geological profile prediction ahead of tunnel face significantly while allowing continuously TBM excavation works. Identifying weak zones or faults ahead of tunnel face is crucial for preventative measures to be carried out in advance for a safer tunnel excavation works.

  1. Vehicle fires and fire safety in tunnels (United States)


    Tunnels present what is arguably the most hazardous environment, from the point of view of fire safety, that members of the public ever experience. The fire safety design of tunnels is carried out by tunnel engineers on the basis of a potential fire ...

  2. Towards international excavation tasks

    NARCIS (Netherlands)

    Ike, Paul


    Over the last twenty years social opposition to mineral excavation has increased to such an extent in the densely populated Netherlands, that it is getting extremely difficult to discover new sites for quarrying coarse sand for concrete. While the Dutch government has attempted for many years to

  3. Numerical modeling of tunneling-induced seismicity (United States)

    Rinaldi, Antonio Pio; Urpi, Luca


    Removal of rock mass in mining environment has been associated since long-time with seismic event of magnitude 3 and above, with the potential to cause damage to the infrastructures or even loss of human life. Although with similarities with mining, relatively unknown up to now are seismic events induced by tunneling. However with modern mechanized tunneling techniques, making possible to digging deeper and longer underground infrastructure, the risk is not negligible. As an example, the excavation of the 57km long Gotthard Base Tunnel has been associated more than hundred seismic events, with the largest one having magnitude of ML 2.4, damaging the tunnel infrastructures. For future scenario of deep geological storage of nuclear waste, tunneling will constitute the primary activity during site construction. Hence, it will be crucial to understand the risk associated with the underground construction operation that can reactivate seismogenic features nearby the future location of emplacement tunnels. Here we present numerical simulation aimed at understanding the potential for inducing seismicity during tunnel construction. The stress changes and their evolution during the excavation are evaluated with a finite element solver (FLAC3d). A strain-softening friction model is then used to simulate the occurrence of a sudden slip on a fault zone (if critical conditions for reactivation are reached). We also present a sensitivity analysis of the potential for inducing different seismic events by different tunnel sizes at varying distance from a nearby failure plane, with the final purpose of evaluating safety of a potential nuclear repository site on the short- and long-term.

  4. Back-analysing rock mass modulus from monitoring data of two tunnels in Sydney, Australia

    Directory of Open Access Journals (Sweden)

    Robert Bertuzzi


    Full Text Available This paper presents two case studies where the rock mass modulus and in situ stress are estimated from the monitoring data obtained during the construction of underground excavations in Sydney, Australia. The case studies comprise the widening of existing twin road tunnels within Hawkesbury sandstone and the excavation of a large cavern within Ashfield shale. While back-analysis from detailed systematic monitoring has been previously published, this paper presents a relatively simple methodology to derive rock mass modulus and in situ stress from the relatively simple displacement data routinely recorded during tunnelling.

  5. Contiguous Pile Wall as a Deep Excavation Supporting System

    Directory of Open Access Journals (Sweden)

    Venkata Ramasubbarao GODAVARTHI


    Full Text Available Providing space for parking, public amenities, etc in multi-storey buildings at town centres has created a need to go deep excavations into ground. Deep excavations are supported by systems like conventional retaining walls, sheet pile walls, braced walls, diaphragm walls and pile walls. This article describes various excavation supporting systems that are in vogue essentially contiguous pile wall and its advantages. A detailed design methodology of an excavation supporting system is furnished in this study. A case study on the Contiguous pile wall retaining system for supporting a deep excavation at a town centre is presented.

  6. Tunnel magnetoresistance in epitaxially grown magnetic tunnel junctions using Heusler alloy electrode and MgO barrier

    Energy Technology Data Exchange (ETDEWEB)

    Tsunegi, S.; Sakuraba, Y.; Oogane, M.; Telling, N. D.; Shelford, L. R.; Arenholz, E.; van der Laan, G.; Hicken, R. J.; Takanashi, K.; Ando, Y.


    Epitaxially grown magnetic tunnel junctions (MTJs) with a stacking structure of Co{sub 2}MnSi/MgO/CoFe were fabricated. Their tunnel magnetoresistance (TMR) effects were investigated. The TMR ratio and tunnelling conductance characteristics of MTJs were considerably different between those with an MgO barrier prepared using sputtering (SP-MTJ) and those prepared using EB evaporation (EB-MTJ). The EB-MTJ exhibited a very large TMR ratio of 217% at room temperature and 753% at 2 K. The bias voltage dependence of the tunnelling conductance in the parallel magnetic configuration for the EB-MTJ suggests that the observed large TMR ratio at RT results from the coherent tunnelling process through the crystalline MgO barrier. The tunnelling conductance in the anti-parallel magnetic configuration suggests that the large temperature dependence of the TMR ratio results from the inelastic spin-flip tunnelling process.

  7. Sediment and Cavitation Erosion Studies through Dam Tunnels

    Directory of Open Access Journals (Sweden)

    Muhammad Abid


    Full Text Available This paper presents results of sediment and cavitation erosion through Tunnel 2 and Tunnel 3 of Tarbela Dam in Pakistan. Main bend and main branch of Tunnel 2 and outlet 1 and outlet 3 of Tunnel 3 are concluded to be critical for cavitation and sediment erosion. Studies are also performed for increased sediments flow rate, concluding 5 kg/sec as the critical value for sudden increase in erosion rate density. Erosion rate is concluded to be the function of sediment flow rate and head condition. Particulate mass presently observed is reasonably low, hence presently not affecting the velocity and the flow field.

  8. Excavation of Regolith by Impinging Jets of Gas (United States)

    Metzger, Philip T.; Immer, Christopher D.; Vu, Bruce T.; Donahue, Carly M.


    There are many situations in nature and technology where particulate matter is excavated by a fluid jet. Such a process is often used to excavate soil or to dig wells. Air jets are often used to transport particulate matter such as powders in various industrial processes. Similar situations occur in nature, as when waterfalls scour holes in sand. In other cases, the excavation is unwanted such as when a rocket lands on the sandy or dusty surface of a planet or moon. Recent research into regolith excavation by gas jets has obtained new insights into the physical processes of that excavation, and these may lead to new advances in technology for more efficient fluid-jet excavation processes and for better control of the unwanted excavation effects of landing rockets. This talk will explain the new insights and point to future work supporting lunar exploration.

  9. Supersonic and hypersonic quiet tunnel technology at NASA Langley (United States)

    Wilkinson, S. P.; Anders, S. G.; Chen, F.-J.; Beckwith, I. E.


    Quiet tunnel technology at NASA Langley is reviewed focusing on historical background, basic quiet tunnel concepts, design methodology, and significant results. Each of the NASA Langley quiet tunnels and recent flow quality results for a refurbished Mach 6 quiet nozzle are presented. It is concluded that high-speed quiet tunels should be viewed as a required adjunct to computational and experimental tools being developed to explore issues of instability and transition physics. The quiet tunnel technology can produce and maintain an adequately smooth nozzle finish, control settling chamber disturbances, and keep the facility clean and is capable of adequately measuring flow disturbances.

  10. Safety and efficacy of endoscopic excavation for gastric subepithelial tumors originating from the muscularis propria layer: results from a large study in China. (United States)

    Zhang, Yu; Ye, Li-Ping; Zhou, Xian-Bin; Mao, Xin-Li; Zhu, Lin-Hong; He, Bi-Li; Huang, Qin


    In this retrospective study, we investigated the safety and efficacy of endoscopic excavation of gastric subepithelial tumors (SETs) originating from the muscularis propria (MP) layer. Between November 2007 and June 2012, 212 patients with gastric SETs originating from the MP layer were treated via endoscopic excavation. The key procedures were: (1) injecting a mixture solution (100 mL saline+2 mL indigo carmine+1 mL epinephrine) into the submucosa around the tumor; (2) making a cross-incision of the mucosa and then excavating the tumor by the technique of endoscopic excavation. After the tumor was completely excavated from the MP layer, it was removed using a snare; (3) closing the artificial ulcer with clips. The mean diameter of the 212 tumors was 16.5 mm. Complete resection by endoscopic excavation was achieved in 204 cases (96.2%). The rate of complete resection was significantly higher for tumors 2 cm (91.9%) (P=0.035). Perforation occurred in 32 cases (15.1%), and massive bleeding occurred in 9 cases (4.2%) during the procedure. The rate of perforation was significantly higher for the fundus and the body than for antrum (21.5%, 11.5%, 0%, respectively; P=0.036), and also differed significantly in relation to histologic diagnosis (23.7% for gastrointestinal stromal tumors vs. 7.8% for leiomyoma; P=0.001). Histologic diagnosis showed that the density of gastrointestinal stromal tumors located in the fundus and the body of the stomach was significantly higher than in the antrum (44.1%, 51.9%, 13.3%, respectively; P=0.036). Endoscopic excavation is a safe and efficient method for resecting small (>3.5 cm) gastric SETs originating from the MP layer.

  11. Kinesiotherapy and physical therapy for carpal tunnel syndrome


    Sochová, Jitka


    Author: Jitka Sochová Institution: Department of Rehabilitation Medicine The Faculty of Medicine in Hradec Králové Title: Kinesiotherapy and physical therapy for carpal tunnel syndrome Supervisor: Mgr. Zuzana Hamarová Pages: 128 Inserts: 7 The year of presentation: 2013 Keywords: Carpal tunnel, rehabilitation therapy, entrapment syndromes, electromyography This Bachelor Diploma deals with carpal tunnel syndrome. In theoretical part I focus on anatomy, lead and innervation of the median nerve,...

  12. Markovian Geology Prediction Approach and its Application in Mountain Tunnels


    Guan, Zhenchang; Deng, Tao; Du, Saizhao; Li, Bo; Jiang, Yujing


    A geology prediction approach based on Markov random process and Bayesian updating procedure is presented in this article. It can dynamically predict the ground conditions ahead of tunnel face in a probabilistic way with very low cost, when the tunnel face advances and new geological information is revealed. The application case study on Chuangshi Tunnel project shows that the prediction results fit the real grounds condition well, especially for the short range ahead of face. This approach c...

  13. Proceedings of the meeting on tunneling reaction and low temperature chemistry, 97 October. Tunneling reaction and quantum medium

    Energy Technology Data Exchange (ETDEWEB)

    Miyazaki, Tetsuo; Aratono, Yasuyuki; Ichikawa, Tsuneki; Shiotani, Masaru [eds.


    Present report is the proceedings of the 3rd Meeting on Tunneling Reaction and Low Temperature Chemistry held in Oct. 13 and 14, 1997. The main subject of the meeting is `Tunneling Reaction and Quantum Medium`. In the meeting, the physical and chemical phenomena in the liquid helium such as quantum nucleation, spectroscopy of atoms and molecules, and tunneling abstraction reaction of tritium atom were discussed as the main topics as well as the tunneling reactions in the solid hydrogen and organic compounds. Through the meetings held in 1995, 1996, and 1997, the tunneling phenomena proceeding at various temperatures (room temperature to mK) in the wide fields of chemistry, biology, and physics were discussed intensively and the importance of the tunneling phenomena in the science has been getting clear. The 12 of the presented papers are indexed individually. (J.P.N.)


    Franklin, Mackenzie L; Day, Shelley


    To describe a case of bilateral choroidal excavation in a patient with juvenile localized scleroderma. Case report. An asymptomatic 12-year-old boy with localized scleroderma presented for examination and was found to have bilateral areas of choroidal excavation temporal to the fovea. Previous reports of ocular complications of localized scleroderma have primarily described adnexal and anterior segment changes. This is the second report of choroidal changes in a patient with localized scleroderma, and the first in a pediatric patient.

  15. Short tunnels.

    NARCIS (Netherlands)

    Schreuder, D.A.


    Before dealing with the question of lighting short tunnels, it is necessary define what is meant by a tunnel and when it should be called 'short'. Confined to motorized road traffic the following is the most apt definition of a tunnel: every form of roofing-over a road section, irrespective of it

  16. Quantum Tunnelling to the Origin and Evolution of Life. (United States)

    Trixler, Frank


    Quantum tunnelling is a phenomenon which becomes relevant at the nanoscale and below. It is a paradox from the classical point of view as it enables elementary particles and atoms to permeate an energetic barrier without the need for sufficient energy to overcome it. Tunnelling might seem to be an exotic process only important for special physical effects and applications such as the Tunnel Diode, Scanning Tunnelling Microscopy (electron tunnelling) or Near-field Optical Microscopy operating in photon tunnelling mode. However, this review demonstrates that tunnelling can do far more, being of vital importance for life: physical and chemical processes which are crucial in theories about the origin and evolution of life can be traced directly back to the effects of quantum tunnelling. These processes include the chemical evolution in stellar interiors and within the cold interstellar medium, prebiotic chemistry in the atmosphere and subsurface of planetary bodies, planetary habitability via insolation and geothermal heat as well as the function of biomolecular nanomachines. This review shows that quantum tunnelling has many highly important implications to the field of molecular and biological evolution, prebiotic chemistry and astrobiology.

  17. Sacred activity by the Method of Excavation

    Directory of Open Access Journals (Sweden)

    Eliana Anjos Furtado


    Full Text Available Excavation is a clinical and teaching methodology created by the first author of this article. It constitutes a way of helping subjects think, make and speak. This process occurs through the xcavation of making, unblinding and/or unveiling elements in search for the understanding of sacred activity. Through xcavation, subjects understand their thoughts, values and the society in which they live in as they excavate their life stories and their relations with making, including their daily, social and work activities. We applied a thoughtful analysis to approach the role of excavation and the concept of sacred activity. Sacred activity is the core activity of every human being, which is not necessarily the activity we perform in our everyday or work life. Sacred activity is that in which subjects are inserted and experience integrally, genuinely and with no masking. Through sacred activities, subjects surrender, not only to the activity itself, but also to the other, to himself and into himself, by quest. Seeking sacred activity is, therefore, a process of questioning, excavating the routine of subjects, watching and understanding the content of this excavation, replacing and adjusting what is being unveiled, and thus making this activity sacred. In this analysis, we concluded that, by the method of excavation, the sacralization of this action should allow subjects to have tender relationships, and thus be cured.

  18. Focal choroidal excavation complicated by choroidal neovascularization. (United States)

    Xu, Haifeng; Zeng, Fanxing; Shi, Depeng; Sun, Xiaolei; Chen, Xiuli; Bai, Yao


    To evaluate the clinical findings of focal choroidal excavation (FCE) complicated by choroidal neovascularization (CNV). Retrospective, observational case series. Twelve patients (15 eyes) with FCE and CNV. The medical records of the patients were reviewed. Clinical findings including age, sex, refraction, color photography, fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), and spectral-domain optical coherence tomography (OCT) were analyzed. Fundus fluorescein angiography, ICGA, and OCT findings. The 12 patients included 6 women and 6 men. The mean age was 46.8±13.4 years (range, 26-64 years). One half of the patients were emmetropic, and the others were myopic (-0.5 to -3.0 diopters). All subjects were Chinese. Before CNV development, normal appearance or nonspecific pigment disturbance could be seen around the choroidal excavation. Corresponding to the excavation, window defects were observed by FFA, whereas hypofluorescence was found on ICGA images. Choroidal neovascularization in all eyes was classic as revealed by FFA. The OCT images showed that all eyes had a single choroidal excavation. In 7 of the 15 eyes, the choroidal excavation was located subfoveally, and in the other 8 eyes, it was eccentric. All CNV lesions grew from the bottom or slope of the excavation. Three patients had bilateral involvement. Choroidal neovascularization occurred in both conforming and nonconforming type FCEs, regardless of whether the excavation was shallow or deep, subfoveal or eccentric. All CNV lesions responded well to intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents. After a single injection, CNV regressed in 13 of 15 eyes. Two eyes received an additional injection. Nonconforming FCE changed to the conforming type after successful treatment of CNV. Focal choroidal excavation is not always stable. Choroidal neovascularization commonly can be seen in patients with FCE and responds well to intravitreal anti-VEGF agents

  19. Proceedings of the meeting on tunneling reaction and low temperature chemistry, 98 August. Tunneling reaction and its theory

    Energy Technology Data Exchange (ETDEWEB)

    Miyazaki, Tetsuo; Aratono, Yasuyuki; Ichikawa, Tsuneki; Shiotani, Masaru [eds.


    Present report is the proceedings of the 4th Meeting on Tunneling Reaction and Low Temperature Chemistry held in August 3 and 4, 1998. The main subject of the meeting is `Tunneling Reaction and Its Theory`. In the present meeting the theoretical aspects of tunneling phenomena in the chemical reaction were discussed intensively as the main topics. Ten reports were presented on the quantum diffusion of muon and proton in the metal and H{sub 2}{sup -} anion in the solid para-hydrogen, the theory of tunnel effect in the nuclear reaction and the tunneling reaction in the organic compounds. One special lecture was presented by Prof. J. Kondo on `Proton Tunneling in Solids`. The 11 of the presented papers are indexed individually. (J.P.N.)

  20. Effect of the mineral precipitation-dissolution at tunnel walls during the operational and post-operational phases

    Energy Technology Data Exchange (ETDEWEB)

    Domenech, Cristina; Arcos, David; Duro, Lara; Grandia, Fidel [Enviros Consul ting, Valldoreix, Barcelona (Spain)


    The extent of reversibility of the geochemical conditions disturbed during the construction and operational phases is of importance in order to assess the chemical evolution of the repository system. In this regard, it is essential to have a deep understanding of the chemical status of the repository system at closure in order to describe its immediate geochemical evolution beyond this point. This project assesses the dissolution and precipitation of minerals due to the interaction with groundwater in the deposition tunnel wall-rock during the operational phase (prior to tunnel backfilling) and during the saturation phase, also considering the effect on the backfill material. We have performed a 2D model in which a fracture intersecting the main tunnel has been considered. The project has been developed in two consecutive stages. The first stage simulates the precipitation and dissolution of minerals in the tunnel wall rock during the operational phase (100 years after excavation) when the tunnel is empty and filled with air. During this stage, water flows through fractures into the tunnel. The results of the model suggest that the interaction between groundwater, fracture-filling minerals, and atmospheric O{sub 2}(g) and CO{sub 2}(g) present in the tunnel leads to the precipitation of secondary minerals (calcite and iron(III) oxy-hydroxide) that do not significantly affect the porosity of the area surrounding the tunnel. The second stage starts after the operational phase, once the tunnel is backfilled, and simulates the interaction of groundwater with fracture-filling minerals and the backfill material. The model implemented assumes that the backfill is already water saturated and that water flows following the regional head gradient. Moreover, it also assumes that O2(g) is still present in the tunnel wall, as a result of the operational phase disturbances. The results show that oxygen will oxidise pyrite in the backfill and promote the precipitation of Fe

  1. The relationship of geophysical measurements to engineering and construction parameters in the Straight Creek Tunnel pilot bore, Colorado (United States)

    Scott, J.H.; Lee, F.T.; Carroll, R.D.; Robinson, C.S.


    Seismic-refraction and electrical-resistivity measurements made along the walls of the Straight Creek Tunnel pilot bore indicate that both a low-velocity and a high-resistivity layer exist in the disturbed rock surrounding the excavation. Seismic measurements were analyzed to obtain the thickness and seismic velocity of rock in the low-velocity layer, the velocity of rock behind the layer and the amplitude of seismic energy received at the detectors. Electrical-resistivity measurements were analyzed to obtain the thickness and electrical resistivity of the high-resistivity layer and the resistivity of rock behind the layer. The electrical resistivity and the seismic velocity of rock at depth, the thickness of rock in the low-velocity layer, and the relative amplitude of seismic energy were correlated against the following parameters, all of which are important in tunnel construction: height of the tension arch, stable vertical rock load, rock quality, rate of construction and cost per foot, percentage of lagging and blocking, set spacing, and type and amount of steel support required, The correlations were statistically meaningful, having correlation coefficients ranging in absolute value from about 0??7 to nearly 1??0. This finding suggests the possibility of predicting parameters of interest in tunnel construction from geophysical measurements made in feeler holes drilled ahead of a working face. Predictions might be based on correlations established either during the early stages of construction or from geophysical surveys in other tunnels of similar design in similar geologic environments. ?? 1968.

  2. Characteristics of Braced Excavation under Asymmetrical Loads

    Directory of Open Access Journals (Sweden)

    Changjie Xu


    Full Text Available Numerous excavation practices have shown that large discrepancies exist between field monitoring data and calculated results when the conventional symmetry-plane method (with half-width is used to design the retaining structure under asymmetrical loads. To examine the characteristics of a retaining structure under asymmetrical loads, we use the finite element method (FEM to simulate the excavation process under four different groups of asymmetrical loads and create an integrated model to tackle this problem. The effects of strut stiffness and wall length are also investigated. The results of numerical analysis clearly imply that the deformation and bending moment of diaphragm walls are distinct on different sides, indicating the need for different rebar arrangements when the excavation is subjected to asymmetrical loads. This study provides a practical approach to designing excavations under asymmetrical loads. We analyze and compare the monitoring and calculation data at different excavation stages and find some general trends. Several guidelines on excavation design under asymmetrical loads are drawn.

  3. Focal choroidal excavation in eyes with central serous chorioretinopathy. (United States)

    Ellabban, Abdallah A; Tsujikawa, Akitaka; Ooto, Sotaro; Yamashiro, Kenji; Oishi, Akio; Nakata, Isao; Miyake, Masahiro; Akagi-Kurashige, Yumiko; Ueda-Arakawa, Naoko; Arichika, Shigeta; Yoshitake, Shin; Takahashi, Ayako; Yoshimura, Nagahisa


    To study the prevalence and 3-dimensional (3-D) tomographic features of focal choroidal excavations in eyes with central serous chorioretinopathy (CSC) using swept-source optical coherence tomography (OCT). Prospective, cross-sectional study. We examined 116 consecutive eyes with CSC with a prototype 3-D swept-source OCT. 3-D images of the shape of the macular area, covering 6 × 6 mm(2), were reconstructed by segmentation of the outer surface of the retinal pigment epithelium (RPE). The 3-D swept-source OCT detected focal choroidal excavations in 9 eyes (7.8%). The 3-D scanning protocol, coupled with en face scans, allowed for clear visualization of the excavation morphology. In 5 eyes with focal excavations, unusual choroidal tissue was found beneath the excavation, bridging the bottom of the excavation and the outer choroidal boundary. Additionally, 3 of those 5 eyes showed a suprachoroidal space below the excavation, as if the outer choroidal boundary is pulled inward by this bridging tissue. The focal choroidal excavations were located within fluorescein leakage points and areas of choroidal hyperpermeability. Eyes with focal choroidal excavations were more myopic (-4.42 ± 2.92 diopters) than eyes without excavations (-0.27 ± 1.80 diopters, P = .001). Subfoveal choroidal thickness was significantly thinner (301.3 ± 60.1 μm) in eyes with focal excavations than in eyes without the excavations (376.6 ± 104.8 μm, P = .036). Focal choroidal excavations were present in 7.8% of eyes with CSC. In these eyes, focal choroidal excavations may have formed from RPE retraction caused by focal scarring of choroidal connective tissue. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Tunnel Face Stability and the Effectiveness of Advance Drainage Measures in Water-Bearing Ground of Non-uniform Permeability (United States)

    Zingg, Sara; Anagnostou, Georg


    Non-uniform permeability may result in complex hydraulic head fields with potentially very high hydraulic gradients close to the tunnel face, which may be adverse for stability depending on the ground strength. Pore pressure relief by drainage measures in advance of the tunnel excavation improves stability, but the effectiveness of drainage boreholes may be low in the case of alternating aquifers and aquitards. This paper analyses the effects of hydraulic heterogeneity and advance drainage quantitatively by means of limit equilibrium computations that take account of the seepage forces acting upon the ground in the vicinity the tunnel face. The piezometric field is determined numerically by means of steady-state, three-dimensional seepage flow analyses considering the heterogeneous structure of the ground and a typical advance drainage scheme consisting of six axial boreholes drilled from the tunnel face. A suite of stability analyses was carried out covering a wide range of heterogeneity scales. The computational results show the effect of the orientation, thickness, location, number and permeability ratio of aquifers and aquitards and provide valuable indications about potentially critical situations, the effectiveness of advance drainage and the adequate arrangement of drainage boreholes. The paper shows that hydraulic heterogeneity results in highly variable face behaviour, even if the shear strength of the ground is constant along the alignment, but ground behaviour is considerably less variable in the presence of advance drainage measures.

  5. Shaft Excavation in Frozen Ground at Point 5

    CERN Document Server

    Osborne, J


    Construction work on the 112 MCHF civil engineering contract started at Point 5 in August 1998. The new surface buildings and underground structures are necessary to accommodate the CMS detector for the LHC Project. The principal underground works consist of two new shafts, two parallel caverns separated by a supporting pillar, and a number of small connection tunnels and service galleries. The two shafts are to be sunk through approximately 50 m of water-bearing moraine to the underlying molasse rock. From a number of possible construction methods, ground freezing of the moraine was considered to be most appropriate. The ground freezing is used to control the groundwater and to support temporarily the moraine during excavation and lining of the shafts. The aim of this paper is to present the ground-freezing technique and to discuss the advantages and disadvantages of the system in the light of its first few months of running on the Point 5 site.

  6. Rock Mass Grouting in the Løren Tunnel: Case Study with the Main Focus on the Groutability and Feasibility of Drill Parameter Interpretation (United States)

    Høien, Are Håvard; Nilsen, Bjørn


    The Løren road tunnel is a part of a major project at Ring road 3 in Oslo, Norway. The rock part of the tunnel is 915 m long and has two tubes with three lanes and breakdown lanes. Strict water ingress restriction was specified and continuous rock mass grouting was, therefore, carried out for the entire tunnel, which was excavated in folded Cambro-Silurian shales intruded by numerous dykes. This paper describes the rock mass grouting that was carried out for the Løren tunnel. Particular emphasis is placed on discussing grout consumption and the challenges that were encountered when passing under a distinct rock depression. Measurement while drilling (MWD) technology was used for this project, and, in this paper, the relationships between the drill parameter interpretation (DPI) factors water and fracturing are examined in relation to grout volumes. A lowering of the groundwater table was experienced during excavation under the rock depression, but the groundwater was nearly re-established after completion of the main construction work. A planned 80-m watertight concrete lining was not required to be built due to the excellent results from grouting in the rock depression area. A relationship was found between leakages mapped in the tunnel and the DPI water factor, indicating that water is actually present where the DPI water factor shows water in the rock. It is concluded that, for the Løren tunnel, careful planning and high-quality execution of the rock mass grouting made the measured water ingress meet the restrictions. For future projects, the DPI water factor may be used to give a better understanding of the material in which the rock mass grouting is performed and may also be used to reduce the time spent and volumes used when grouting.

  7. Geological Hazards analysis in Urban Tunneling by EPB Machine (Case study: Tehran subway line 7 tunnel

    Directory of Open Access Journals (Sweden)

    Hassan Bakhshandeh Amnieh


    Full Text Available Technological progress in tunneling has led to modern and efficient tunneling methods in vast underground spaces even under inappropriate geological conditions. Identification and access to appropriate and sufficient geological hazard data are key elements to successful construction of underground structures. Choice of the method, excavation machine, and prediction of suitable solutions to overcome undesirable conditions depend on geological studies and hazard analysis. Identifying and investigating the ground hazards in excavating urban tunnels by an EPB machine could augment the strategy for improving soil conditions during excavation operations. In this paper, challenges such as geological hazards, abrasion of the machine cutting tools, clogging around these tools and inside the chamber, diverse work front, severe water level fluctuations, existence of water, and fine-grained particles in the route were recognized in a study of Tehran subway line 7, for which solutions such as low speed boring, regular cutter head checks, application of soil improving agents, and appropriate grouting were presented and discussed. Due to the presence of fine particles in the route, foam employment was suggested as the optimum strategy where no filler is needed.

  8. Heart rot hotel: fungal communities in red-cockaded woodpecker excavations (United States)

    Michelle A. Jusino; Daniel L. Lindner; Mark T. Banik; Jeffrey R. Walters


    Tree-cavity excavators such as woodpeckers are ecosystem engineers that have potentially complex but poorly documented associations with wood decay fungi. Fungi facilitate cavity excavation by preparing and modifying excavation sites for cavity excavators. Associations between fungi and endangered red-cockaded woodpeckers (RCWs) are particularly interesting because...

  9. Quasi-bound states, resonance tunnelling, and tunnelling times ...

    Indian Academy of Sciences (India)

    Abstract. In analogy with the definition of resonant or quasi-bound states used in three-dimensional quantal scattering, we define the quasi-bound states that occur in one- dimensional transmission generated by twin symmetric potential barriers and evaluate their energies and widths using two typical examples: (i) twin ...

  10. New concept of tunnel boring machine: high performance using water jet and diamond wire as rock cutting technology

    Directory of Open Access Journals (Sweden)

    Rafael Pacheco dos Santos

    Full Text Available Abstract Tunnel boring machines are important tools in underground infrastructure projects. Although being well established equipment, these machinesare based on designsof more than 60 years ago and are characterized by big dimensions, enormous weight and high power consumption. Commercial aspects should be noted too. The model adopted by the TBM industry requires constant replacement of cutter discs and specific labor skills, usually offered by the same manufacturingcompany. In some cases the cost of replacement parts and technical assistance can be higher than the acquisition cost of an entire machine. These aspects are no longer compatible with the concept of sustainability that is an important aspect of currentsociety. While the technical characteristics require a large quantity of steel and several inputs, the adoptedmodel is not competitive. One alternative is looking for new technologies that break the old paradigms and allow the development of high performance concepts with lower social and environmental impact. This studydealswith this opportunity by proposing a high performance tunnel boring machine that makes use of high power water jet and diamond wire to compose a double shield cutter head. It works in two stages. In the fristone, an annular cut is executed by hydrodemolition,and in the second one, the diamond wire station slices the rock core. Only with the action of diamond wire is the rock core separated from the rock mass and the removal process is finished. A smart water jet nozzle movement system is described and non circular tunnels can be executed. The new technologies involved requirea different type of backup system, lighter and smaller. The non-existence of mechanical contact between the equipment and the rock mass at theexcavation front allows low power consumption. The advanced rate and primary excavation cost analyses can also be encountered herein. It shows that it is possible to reach an advanced rate of 174 m/day in

  11. Design Recommendations for Concrete Tunnel Linings : Volume II. Summary of Research and Proposed Recommendations. (United States)


    The report presents design recommendations for concrete tunnel linings for transportation tunnels. The recommendations developed as a result of in-depth analysis and model testing of the behavior of concrete tunnel linings. The research addressed pro...

  12. Expected and Actual Improvement of Symptoms With Carpal Tunnel Release

    NARCIS (Netherlands)

    Becker, Stéphanie J. E.; Makanji, Heeren S.; Ring, David


    Purpose This study tested the null hypothesis that there is no difference between expected improvement and actual improvement of symptoms with carpal tunnel release (CTR). Secondary analyses addressed factors associated with both expected relief and actual relief of symptoms with carpal tunnel

  13. Comparison of visual observation and excavation to quantify density of the endangered bivalve Unio crassus in rivers of north-eastern France

    Directory of Open Access Journals (Sweden)

    Lamand F.


    Full Text Available In the context of a rapid decline in several protected unionid species, government agencies urgently require a reliable method to estimate population size for the most endangered species. We used a dataset collected from 16 river stations in north-eastern France to compare the efficiency of visual estimation (bathyscope and a manual excavation to estimate numbers of the endangered bivalve Unio crassus. Our investigations indicated that, whereas a visual approach was sufficient to detect unionid presence, only 10% of all individuals were registered compared with manual excavation at the same site. In order to obtain an accurate density estimate (especially as regards the juvenile population, sediment excavation is necessary, despite it being time consuming and damaging to the mussel’s habitat.

  14. Multiple Ligament Reconstruction Femoral Tunnels: Intertunnel Relationships and Guidelines to Avoid Convergence. (United States)

    Moatshe, Gilbert; Brady, Alex W; Slette, Erik L; Chahla, Jorge; Turnbull, Travis Lee; Engebretsen, Lars; LaPrade, Robert F


    Knee dislocations often require multiple concurrent ligament reconstructions, which involve creating several tunnels in the distal femur. Therefore, the risk of tunnel convergence is increased because of the limited bone volume within the distal aspect of the femur. To assess the risk of tunnel convergence and determine the optimal reconstruction tunnel orientations for multiple ligament reconstructions in the femur. Descriptive laboratory study. Three-dimensional knee models were developed from computed tomography scans of 21 patients. Medical image processing software was used to create tunnels for each of the primary ligamentous structures, replicating a surgical approach that would be used in multiple ligament reconstructions. Thereafter, the tunnel orientation was varied in surgically relevant directions to determine orientations that minimized the risk of tunnel convergence. The orientation of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) tunnels was held constant throughout the study, while the orientation of the fibular collateral ligament (FCL), popliteus tendon (PLT), superficial medial collateral ligament (sMCL), and posterior oblique ligament (POL) tunnels was varied to avoid convergence. A high risk of tunnel convergence was observed between the FCL and ACL tunnels when the FCL tunnel was aimed at 0° in the axial and coronal planes. Aiming the FCL tunnel 35° anteriorly minimized convergence with the ACL tunnel. No tunnel convergence was observed for the PLT tunnel aimed 35° anteriorly and parallel to the FCL tunnel. To avoid convergence between the sMCL and PCL tunnels, the sMCL tunnels should be aimed 40° proximally in the coronal plane and 20° to 40° anteriorly. During concomitant POL reconstruction, the sMCL should be aimed 40° proximally and anteriorly and the POL 20° proximally and anteriorly. The PLT and POL tunnels aimed at 0° in both the coronal and axial planes had an increased risk of violating the

  15. Group Parametrized Tunneling and Local Symmetry Conditions (United States)

    Harter, William; Mitchell, Justin


    Recently, Hougen showed an ad hoc symmetry-based parameterization scheme for analyzing tunneling dynamics and high resolution spectra of fluxional molecular structure similar to S-parameter analysis of superfine structure in SF_6 or NH_3 maser inversion dynamics by Feynman The problem is that ad hoc parametrization, like path integration in general, can lead to logjams of parameters or ``paths'' with no way to pick out the relevant ones. We show a way to identify and use relevant parameters for a tunneling Hamiltonian H having global G-symmetry-defined bases by first expressing H as a linear combination bar γ ^i {bar g}_i of operators in dual symmetry group bar G. The coefficients bar γ ^i are parameters that define a complete set of allowed paths for any H with G-symmetry and are related thru spectral decomposition of G to eigensolutions of H. Quantum G G duality generalizes lab -vs. -body and state -vs. -particle. The number of relevant bar γ ^i-parameters is reduced if a system tends to stick in states of a local symmetry subgroup LsubsetG so the H spectrum forms level clusters labeled by induced representations d(ℓ)(L)\\uparrowG. A cluster-(ℓ) has one E(epsilon)-level labeled by G species (epsilon) for each L species (ℓ) in Depsilon(G)downarrowL by Frobenius reciprocity. Then we apply local symmetry conditions to each irrep Depsilon(bar γ ^i {bar g}_i) that has already been reduced with respect to local symmetry L. This amounts to setting each off-diagonal component Dj,kepsilon(H) to zero. Local symmetry conditions may tell which bar γ ^i-parameters are redundant or zero and directly determine d(ℓ)\\uparrowG tunneling matrix eigenvalues that give E(epsilon)-levels as well as eigenvectors. Otherwise one may need to choose a particular localizing subgroup chain LsubsetL_1subsetL_2...G and further reduce the number of path parameters to facilitate spectral fitting. J.T. Hougen, 2009 MSS RJ01, {J Mol Spect 123, 197 (1987) W.G. Harter and

  16. Clamshell excavation of a permeable reactive barrier (United States)

    Molfetta, Antonio Di; Sethi, Rajandrea


    Nowadays, permeable reactive barriers (PRB) are one of the most widespread techniques for the remediation of contaminated aquifers. Over the past 10 years, the use of iron-based PRBs has evolved from innovative to accepted standard practice for the treatment of a variety of groundwater contaminants (ITRC in: Permeable reactive barriers: lessons learned/new directions. The Interstate Technology and Regulatory Council, Permeable Reactive Barriers Team 2005). Although, a variety of excavation methods have been developed, backhoe excavators are often used for the construction of PRBs. The aim of this study is to describe the emplacement of a full-scale PRB and the benefits deriving from the use of a crawler crane equipped with a hydraulic grab (also known as clamshell excavator) in the excavation phases. The studied PRB was designed to remediate a chlorinated hydrocarbons plume at an old industrial landfill site, in Avigliana, near the city of Torino, in Italy. The continuous reactive barrier was designed to be 120 m long, 13 m deep, and 0.6 m thick. The installation of the barrier was accomplished using a clamshell for the excavation of the trench and a guar-gum slurry to support the walls. The performance of this technique was outstanding and allowed the installation of the PRB in 7 days. The degree of precision of the excavation was very high because of the intrinsic characteristics of this excavation tool and of the use of a concrete curb to guide the hydraulic grab. Moreover, the adopted technique permitted a saving of bioslurry thus minimizing the amount of biocide required.

  17. Tunnel ionization, population trapping, filamentation and applications (United States)

    Leang Chin, See; Xu, Huailiang


    The advances in femtosecond Ti-sapphire laser technology have led to the discovery of a profusion of new physics. This review starts with a brief historical account of the experimental realization of tunnel ionization, followed by high harmonic generation and the prediction of attosecond pulses. Then, the unique phenomenon of dynamic population trapping during the ionization of atoms and molecules in intense laser fields is introduced. One of the consequences of population trapping in the highly excited states is the neutral dissociation into simple molecular fragments which fluoresce. Such fluorescence could be amplified in femtosecond laser filamentation in gases. The experimental observations of filament-induced fluorescence and lasing in the atmosphere and combustion flames are given. Excitation of molecular rotational wave packets (molecular alignment) and their relaxation and revival in a gas filament are described. Furthermore, filament-induced condensation and precipitation inside a cloud chamber is explained. Lastly, a summary and future outlook is given.

  18. IR and py/GC/MS examination of amber relics excavated from 6th century royal tomb in Korean Peninsula (United States)

    Park, Jongseo; Yun, Eunyoung; Kang, Hyungtae; Ahn, Jooyoung; Kim, Gyuho


    Relics of amber were excavated from King Muryeong's tomb constructed in the 6th century on the Korean peninsula. To estimate the provenance, FTIR (Fourier transform infrared spectroscopy) and py/GC/MS (pyrolysis/gas chromatography/mass spectrometry) analysis were utilized. The reference Baltic amber sample was also analyzed with the same method for comparison. The relics were confirmed to be amber from the FTIR analysis where an absorption band near 1150 cm- 1, characteristic one in Baltic amber, was also observed. In py/GC/MS analysis, pyrolyzed products like butanedioic acid and dehydroabietic acid, known constituents of amber, were observed. In addition, D-fenchyl alcohol, camphor, borneol and butanedioic acid, typical constituents of Baltic amber, were observed in some samples. From this, it appears that some of relics were made from Baltic amber and that Baltic amber was transported to the Korean peninsula in the time of tomb construction.

  19. Infill of tunnel valleys associated with landward‐flowing ice sheets

    DEFF Research Database (Denmark)

    Moreau, Julien; Huuse, Mads


    The southern termination of the Middle and Late Pleistocene Scandinavian ice sheets was repeatedly located in the southern North Sea (sNS) and adjacent, north-sloping land areas. Giant meltwater-excavated valleys (tunnel valleys) formed at the southern termination of the ice sheets and contain...

  20. Cold prebiotic evolution, tunneling, chirality and exobiology

    Energy Technology Data Exchange (ETDEWEB)

    Goldanskii, V.I. [N.N. Semenov Institute of Chemical Physics Russian Academy of Sciences UL.Kosygina 4, 117334 Moscow (Russia)


    The extra-terrestrial scenario of the origin of life suggested by Svante Arrhenius (1) as the {open_quote}panspermia{close_quote} hypothesis was revived by the discovery of a low-temperature quantum limit of a chemical reaction rate caused by the molecular tunneling (2). Entropy factors play no role near absolute zero, and slow molecular tunneling can lead to the exothermic formation of quite complex molecules. Interstellar grains or particles of cometary tails could serve as possible cold seeds of life, with acetic acid, urea and products of their polycondensation as quasi-equilibrium intermediates. Very cold solid environment hinders racemization and stabilizes optical activity under conditions typical for outer space. Neither {open_quote}advantage{close_quote} factors can secure the evolutionary formation of chiral purity of initial prebiotic monomeric medium{emdash}even being temporary achieved it cannot be maintained at subsequent stages of prebiotic evolution because of counteraction of {open_quote}enantioselective pressure{close_quote}. Only bifurcational mechanism of the formation of prebiotic homochiral{emdash}monomeric and afterwards polymeric{emdash}medium and its subsequent transformation in {open_quote}homochiral chemical automata{close_quote} ({open_quote}biological big bang{close_quote}{emdash}passage from {open_quote}stochastic{close_quote} to {open_quote}algorithmic{close_quote} chemistry) is possible and can be realized. Extra-terrestrial (cold, solid phase) scenarios of the origin of life seem to be more promising from that point of view than terrestrial (warm) scenarios. Within a scheme of five main stages of prebiological evolution some problems important for further investigation are briefly discussed. {copyright} {ital 1996 American Institute of Physics.}

  1. Focal choroidal excavation and a traumatic macular hole secondary to accidental Q-switched Nd:YAG laser. (United States)

    Shuai, Yuanlu; Chen, Xianglei; Fang, Wangyi; Li, Jia; Ge, Weizhong; Yuan, Songtao; Liu, Qinghuai


    Today, the widespread use of laser instruments in various fields has resulted in many accidental retinal injuries. Here we describe a rare clinical case of full-thickness macular hole (MH) and focal choroidal excavation (FCE) caused by a 1064-nm Q-switched Nd:YAG laser. After pars plana vitrectomy and the following 14 months, consecutive optical coherence tomography imagings showed closure of the MH. Visual acuity improved even in the absence of the outer retina and in the presence of FCE. We speculate that different focusing effects of the unexpected Nd:YAG lasers which target different levels of retinal tissue generate diverse prognosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Initial Assessment of the Excavation and Deposition of Impact Lithologies Exposed by the Chicxulub Scientific Drilling Project, Yaxcopoil, Mexico (United States)

    Kring, David A.; Horz, Friedrich; Zurcher, Lukas


    The Chicxulub Scientific Drilling Project ( recovered a continuous core from a depth of 404 m (in Tertiary cover) to 1511 m (in a megablock of Cretaceous target sediments), penetrating approx. 100 m of melt-bearing impactites between 794 and 895 m. The Yaxcopoil-1 (YAX-1) borehole is approx. 60-65 km from the center of the Chicxulub structure, which is approx. 15 km beyond the limit of the estimated approx. 50 km radius transient crater (excavation cavity), but within the rim of the estimated approx. 90 km radius final crater. In general, the impactite sequence is incredibly rich in impact melts of unusual textural variety and complexity, quite unlike melt-bearing impact formations from other terrestrial craters.

  3. A Shear-Wave Seismic System to Look Ahead of a Tunnel Boring Machine

    NARCIS (Netherlands)

    Bharadwaj, Pawan; Drijkoningen, G.G.; Mulder, W.A.; Tscharner, Thomas; Jenneskens, Rob


    The Earth’s properties, composition and structure ahead of a tunnel boring machine (TBM) should be mapped for hazard assessment during excavation. We study the use of seismic-exploration techniques for this purpose. We focus on a seismic system for soft soils, where shear waves are better and easier

  4. Pneumatic Excavation Mechanism for Lunar Resource Utilization Project (United States)

    National Aeronautics and Space Administration — Honeybee Robotics, in collaboration with Firestar Engineering, proposes to continue development of a pneumatic regolith excavating, moving and heating approach. With...

  5. The possibilites of coal seam underground excavation in Republic of Macedonia with high productive excavation methods


    Despodov, Zoran; Doneva, Nikolinka; Mijalkovski, Stojance


    The paper presents mining and geology properties of coal deposits in R.Macedonia predetermined for underground exploitation. Also it will be shown the way of coal seams preparation and development for underground excavation with longwall mining methods. Based on mining and geology properties of coal and it’s caloric value it will be observed the possibilities for application on the longwall mining which is among excavation methods with highest production and capacity applied in the contemp...

  6. A Novel Energy Recovery System for Parallel Hybrid Hydraulic Excavator


    Li, Wei; Cao, Baoyu; Zhu, Zhencai; Chen, Guoan


    Hydraulic excavator energy saving is important to relieve source shortage and protect environment. This paper mainly discusses the energy saving for the hybrid hydraulic excavator. By analyzing the excess energy of three hydraulic cylinders in the conventional hydraulic excavator, a new boom potential energy recovery system is proposed. The mathematical models of the main components including boom cylinder, hydraulic motor, and hydraulic accumulator are built. The natural frequency of the pro...

  7. Tunnelling in urban areas by EPB machines: technical evaluation of the system

    Directory of Open Access Journals (Sweden)

    Cardu Marilena


    Full Text Available The paper refers to the methods adopted for building a high-speed railway tunnel system between Bologna and Firenze (Italy, focusing attention on the Bologna node which represents the heart of the system, connecting the high speed network's main lines. The project includes 9 tunnels, accounting for 73 km of the 78 km route crossing below the Apennines. The paper pays attention to the main aspects to be taken into consideration for correctly choosing the tunnel boring machinery (TBM tobe used in urban areas. Thefundamental point in analysing technical aspects regarding an earth pressure balance (
    EPB machine concerned storing the main excavation parameter values; having collected and organised such data, statistical methods were used for processing it, the instantaneous velocities attained were empirically estimated and idle times were evaluated. The evaluation was made by calculating excavation specific energies (during different
    excavation phases to find a satisfactory correlation with the type of ground crossed. Interesting results have been found by comparison with other excavation parameters; in particular, a better understanding of an earth pressure balance shield's working phases has been reached thanks to an experimental study conducted during the construction of tunnels for a high-speed railway system in Italy. The paper contains details collected regarding the operation of two different EPB machines.


    Directory of Open Access Journals (Sweden)

    J. Wang


    Full Text Available Recent years have witnessed a growing investigation of terrestrial laser scanning (TLS for monitoring the deformation of tunnels. TLS provides the ability to obtain a more accurate and complete description of the tunnel surfaces, allowing the determination of the mechanism and magnitude of tunnel deformation, because the entire surface of the tunnel is more concretely modelled rather than being represented by a number of points. This paper models and analyses the point clouds from TLS to detect the possible deformation of a newly built tunnel. In the application of monitoring the Badaling Tunnel for the Winter Olympics 2020 in Beijing, China, the proposed method includes the following components: the tunnel axis is automatically estimated based on a 3D quadratic form estimation; all of the point clouds are segmented into axis-based blocks; and representative points, solved by a singular value decomposition (SVD method, are estimated to describe the tunnel surface and establish the correspondence of data between days. The deformations are detected in the form of the distance discrepancies of representative points and verified by the measurements using total station.

  9. Wind Tunnel Management and Resource Optimization: A Systems Modeling Approach (United States)

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


    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

  10. Carpal tunnel syndrome impairs thumb opposition and circumduction motion. (United States)

    Marquardt, Tamara L; Nataraj, Raviraj; Evans, Peter J; Seitz, William H; Li, Zong-Ming


    Carpal tunnel syndrome is associated with sensory and motor impairments resulting from the compressed and malfunctioning median nerve. The thumb is critical to hand function, yet the pathokinematics of the thumb associated with carpal tunnel syndrome are not well understood. The purpose of this study was to evaluate thumb motion abnormalities associated with carpal tunnel syndrome. We hypothesized that the ranges of translational and angular motion of the thumb would be reduced as a result of carpal tunnel syndrome. Eleven patients with carpal tunnel syndrome and 11 healthy control subjects voluntarily participated in this study. Translational and angular kinematics of the thumb were obtained using marker-based video motion analysis during thumb opposition and circumduction movements. Motion deficits were observed for patients with carpal tunnel syndrome even though maximum pinch strength was similar. The path length, normalized by palm width of the thumb tip for the patients with carpal tunnel syndrome was less than for control participants (opposition: 2.2 palm width [95% CI, 1.8-2.6 palm width] versus 3.1 palm width [95% CI, 2.8-3.4 palm width], p thumb tip ulnarly across the palm during opposition relative to control participants. The angular ROM also was reduced for the patients with carpal tunnel syndrome compared with the control participants in extension/flexion for the metacarpophalangeal (opposition: 34° versus 58°, p = .004; circumduction: 33° versus 58°, p thumb during opposition and circumduction despite normal pinch strength. Improving understanding of thumb pathokinematics associated with carpal tunnel syndrome may help clarify hand function impairment associated with the syndrome given the critical role of the thumb in dexterous manipulation.

  11. Focal Choroidal Excavation in Best Vitelliform Macular Dystrophy: Case Report. (United States)

    Esfahani, Mohammad Riazi; Esfahani, Hamid Riazi; Mahmoudi, Alireza; Johari, Mohammad Karim; Hemati, Karim


    Focal choroidal excavation (FCE) was first reported as a choroidal posteriorly excavated zone without any scleral change. Choroidal excavation also divided into conforming and nonconforming type. Numerous reports demonstrated association between FCE and other disease such as choroidal neovascularization and central serous choroidoretinopathy. Here, we report a rare case of FCE in a patient with Best disease. The patient was diagnosed by spectoral domain optical coherence tomography (SD-OCT). To the best of our knowledge, our patient is the second report of choroidal excavation in Best vitelliform macular dystrophy.

  12. Multivariate Linear Regression and CART Regression Analysis of TBM Performance at Abu Hamour Phase-I Tunnel (United States)

    Jakubowski, J.; Stypulkowski, J. B.; Bernardeau, F. G.


    The first phase of the Abu Hamour drainage and storm tunnel was completed in early 2017. The 9.5 km long, 3.7 m diameter tunnel was excavated with two Earth Pressure Balance (EPB) Tunnel Boring Machines from Herrenknecht. TBM operation processes were monitored and recorded by Data Acquisition and Evaluation System. The authors coupled collected TBM drive data with available information on rock mass properties, cleansed, completed with secondary variables and aggregated by weeks and shifts. Correlations and descriptive statistics charts were examined. Multivariate Linear Regression and CART regression tree models linking TBM penetration rate (PR), penetration per revolution (PPR) and field penetration index (FPI) with TBM operational and geotechnical characteristics were performed for the conditions of the weak/soft rock of Doha. Both regression methods are interpretable and the data were screened with different computational approaches allowing enriched insight. The primary goal of the analysis was to investigate empirical relations between multiple explanatory and responding variables, to search for best subsets of explanatory variables and to evaluate the strength of linear and non-linear relations. For each of the penetration indices, a predictive model coupling both regression methods was built and validated. The resultant models appeared to be stronger than constituent ones and indicated an opportunity for more accurate and robust TBM performance predictions.

  13. Enzyme dynamics and hydrogen tunnelling in a thermophilic alcohol dehydrogenase (United States)

    Kohen, Amnon; Cannio, Raffaele; Bartolucci, Simonetta; Klinman, Judith P.; Klinman, Judith P.


    Biological catalysts (enzymes) speed up reactions by many orders of magnitude using fundamental physical processes to increase chemical reactivity. Hydrogen tunnelling has increasingly been found to contribute to enzyme reactions at room temperature. Tunnelling is the phenomenon by which a particle transfers through a reaction barrier as a result of its wave-like property. In reactions involving small molecules, the relative importance of tunnelling increases as the temperature is reduced. We have now investigated whether hydrogen tunnelling occurs at elevated temperatures in a biological system that functions physiologically under such conditions. Using a thermophilic alcohol dehydrogenase (ADH), we find that hydrogen tunnelling makes a significant contribution at 65°C this is analogous to previous findings with mesophilic ADH at 25°C ( ref. 5). Contrary to predictions for tunnelling through a rigid barrier, the tunnelling with the thermophilic ADH decreases at and below room temperature. These findings provide experimental evidence for a role of thermally excited enzyme fluctuations in modulating enzyme-catalysed bond cleavage.

  14. WKB approximation and tunneling in theories with noncanonical kinetic terms (United States)

    González, Mariana Carrillo; Masoumi, Ali; Solomon, Adam R.; Trodden, Mark


    Tunneling is a fascinating aspect of quantum mechanics that renders the local minima of a potential meta-stable, with important consequences for particle physics, for the early hot stage of the universe, and more speculatively, for the behavior of the putative multiverse. While this phenomenon has been studied extensively for systems which have canonical kinetic terms, many theories of fundamental physics contain fields with noncanonical kinetic structures. It is therefore desirable to have a detailed framework for calculating tunneling rates and initial states after tunneling for these theories. In this work we present such a rigorous formulation and illustrate its use by applying it to a number of examples.

  15. Nanowire Tunnel Field Effect Transistors: Prospects and Pitfalls (United States)

    Sylvia, Somaia Sarwat

    The tunnel field effect transistor (TFET) has the potential to operate at lower voltages and lower power than the field effect transistor (FET). The TFET can circumvent the fundamental thermal limit of the inverse subthreshold slope (S) by exploiting interband tunneling of non-equilibrium "cold" carriers. The conduction mechanism in the TFET is governed by band-to-band tunneling which limits the drive current. TFETs built with III-V materials like InAs and InSb can produce enough tunneling current because of their small direct bandgap. Our simulation results show that although they require highly degenerate source doping to support the high electric fields in the tunnel region, the devices achieve minimum inverse subthreshold slopes of 30 mV/dec. In subthreshold, these devices experience both regimes of voltage-controlled tunneling and cold-carrier injection. Numerical results based on a discretized 8-band k.p model are compared to analytical WKB theory. For both regular FETs and TFETs, direct channel tunneling dominates the leakage current when the physical gate length is reduced to 5 nm. Therefore, a survey of materials is performed to determine their ability to suppress the direct tunnel current through a 5 nm barrier. The tunneling effective mass gives the best indication of the relative size of the tunnel currents. Si gives the lowest overall tunnel current for both the conduction and valence band and, therefore, it is the optimum choice for suppressing tunnel current at the 5 nm scale. Our numerical simulation shows that the finite number, random placement, and discrete nature of the dopants in the source of an InAs nanowire (NW) TFET affect both the mean value and the variance of the drive current and the inverse subthreshold slope. The discrete doping model gives an average drive current and an inverse subthreshold slope that are less than those predicted from the homogeneous doping model. The doping density required to achieve a target drive current is

  16. Measuring the degree of street vitality in excavated towns : How can macro and micro spatial analyses tools contribute to understandings on the spatial organization of urban life in Pompeii?

    NARCIS (Netherlands)

    Van Nes, A.

    The aim of this contribution is to show how it is possible to indicate degrees of street life and economical attractiveness in excavated towns through micro and macro spatial configurative analyses. When applying these tools on excavated sites, socio-economic empirical knowledge from a present urban

  17. Measuring the degree of street vitality in excavated towns : How can macro and micro spatial analyses tools contribute to understandings on the spatial organization of urban life in Pompeii?

    NARCIS (Netherlands)

    Van Nes, A.


    The aim of this contribution is to show how it is possible to indicate degrees of street life and economical attractiveness in excavated towns through micro and macro spatial configurative analyses. When applying these tools on excavated sites, socio-economic empirical knowledge from a present urban

  18. Use of a microdebrider for corporeal excavation and penile prosthesis implantation in men with severely fibrosed corpora cavernosa: a new minimal invasive surgical technique. (United States)

    Bozkurt, İbrahim Halil; Yonguç, Tarık; Aydoğdu, Özgü; Değirmenci, Tansu; Arslan, Murat; Minareci, Süleyman


    To propose a new minimal invasive surgical technique using a microdebrider (shaver) to excavate the fibrosed corpora cavernosa for penile prosthesis implantation in patients with severe fibrosis. Two patients with severe corporeal fibrosis were implanted with a penile prosthesis using this technique. In the first patient, fibrosis was due to neglected idiopathic ischemic priapism and the second patient had his prosthesis extruded because of erosion in another center. Both patients were counseled about the procedure and the possible complications related to the experimental nature of the technique. A written informed consent was obtained from both patients. Excavation of the corpora was performed using microdebrider in both patients. Both operations were performed successfully without any intraoperative complications, including urethral injury or perforation of the tunica. The mean operation time was 57 min. The postoperative period was uneventful without any infection, migration, erosion, or mechanical failure. The penile length was increased nearly 2 cm in both patients, and the penile girth was increased around 30% in the patient who underwent inflatable penile prosthesis implantation. The microdebrider potentially provides an important advance in patients with severe corporeal fibrosis to excavate the fibrosed corpora cavernosa for penile prosthesis implantation. The main advantages include fast, safe, and effective excavation of fibrous corpora cavernosa adequate for a satisfactory penile prosthesis implantation.

  19. A study on excavation of rock mass by lasers. Researching the possibility of utilizing low-power lasers

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Fumio [Taisei Corporation, Technology Research Center, Yokohama, Kanagawa (Japan)


    The object of this research is to develop the techniques of rock-mass excavation by laser irradiation. This rock-mass excavation technique by lasers has a characteristic of extremely little effect to the surroundings of an excavation site no matter how the target rock mass is with regard to geological aspects and given physical property. Moreover, it could be utilized in excavation of waste dump facilities, which need to be re-buried, and applied to excavation of long piles and tunnels, which are drilled through different kinds of strata, and to improvement of rock mass and ground. Lasers have a characteristic of concentrating the energy into a limited point and not only discontinue or cut a large area with a small output like sharp scissors but also block up the cracks deep inside the rock mass by fusing vitrification for its improvement. It leads to restrain the loss of energy, minimization of the effected environment, effective utilization of resources and energy, environmental restoration, and improvement of the working environment. In the field of nuclear fuel, which includes excavating dump pits, dismantling a furnace, and taking appropriate steps of mine remains, excavating, cutting, and fusing could be required to do within a limited space of rock mass or concrete. Up to the present, those things have been done mainly by large machines, but it is too scarce in possibility for them to improve their large size, heavy weight, difficulty in unmanned operation, limited shapes of cutting, and stabilization of waste. In this research the concrete system images have been examined, doing the fundamental researches about higher-power lasers, smaller sizing, transmitting by fibers to find our the breakthrough to realization of laser excavation, This year, as the summary of examining the laser excavation techniques, utilizing a low-power laser, which is thought to be highly effective in rock-mass improvement, will be examined, considering application of the technique

  20. Measurement and Assessment of Flow Quality in Wind Tunnels Project (United States)

    National Aeronautics and Space Administration — New wind tunnel flow quality test and analysis procedures have been developed and will be used to establish standardized turbulent flow quality measurement...

  1. Coexistance of Giant Tunneling Electroresistance and Magnetoresistance in an All-Oxide Composite Magnetic Tunnel Junction

    KAUST Repository

    Caffrey, Nuala Mai


    We propose, by performing advanced abinitio electron transport calculations, an all-oxide composite magnetic tunnel junction, within which both large tunneling magnetoresistance (TMR) and tunneling electroresistance (TER) effects can coexist. The TMR originates from the symmetry-driven spin filtering provided by an insulating BaTiO3 barrier to the electrons injected from the SrRuO3 electrodes. Following recent theoretical suggestions, the TER effect is achieved by intercalating a thin insulating layer, here SrTiO3, at one of the SrRuO3/BaTiO3 interfaces. As the complex band structure of SrTiO3 has the same symmetry as that of BaTiO3, the inclusion of such an intercalated layer does not negatively alter the TMR and in fact increases it. Crucially, the magnitude of the TER also scales with the thickness of the SrTiO3 layer. The SrTiO3 thickness becomes then a single control parameter for both the TMR and the TER effect. This protocol offers a practical way to the fabrication of four-state memory cells. © 2012 American Physical Society.

  2. Stepwise excavation in a permanent molar

    DEFF Research Database (Denmark)

    Lima, Fernanda Ferruzzi; Pascotto, Renata Corrêa; Benetti, Ana Raquel


    The current study presents a 17-year clinical report of stepwise excavation and indirect pulp capping in a lower right first molar, with great dentin destruction and a lack of dentin support of the cusps. At the first appointment, indirect pulp capping with calcium hydroxide and a temporary filling...... with zinc oxide cement were performed to minimize the risk of pulp exposure during excavation. After 45 days, the remaining carious tissue was removed and a restoration with glass-ionomer lining (Vitrebond) and resin composite (P-50) was performed. Satisfactory morphology and function of the restoration...

  3. The expanded spectrum of focal choroidal excavation. (United States)

    Margolis, Ron; Mukkamala, Sri Krishna; Jampol, Lee M; Spaide, Richard F; Ober, Michael D; Sorenson, John A; Gentile, Ronald C; Miller, Joel A; Sherman, Jerome; Freund, K Bailey


    To describe the clinical and imaging findings in patients with focal choroidal excavation. Retrospective observational case series. The medical records of 12 patients (13 eyes) with focal choroidal excavation were reviewed. Clinical histories and imaging findings (including color photography, fundus autofluorescence imaging, fluorescein angiography, indocyanine green angiography, spectral-domain optical coherence tomography, and enhanced depth imaging spectral-domain optical coherence tomography) were analyzed. The mean age of the patients was 45 years (range, 22-62 years). Four patients were Asian. Mean visual acuity was 20/31 (range, 20/20 to 20/100). Mean refractive error was -3.54 diopters (D) (range, 6.00 to -8.00 D). One patient had bilateral involvement. All patients manifested varying degrees of foveal pigmentary changes that were usually hypoautofluorescent on fundus autofluorescence images. Fluorescein angiographic findings varied with degree of retinal pigment epithelial alterations. Indocyanine green angiography revealed relative hypofluorescence. In 7 eyes, spectral-domain optical coherence tomography revealed outer retinal layers conforming to retinal pigment epithelial alterations within the excavation. In the other 6 eyes, spectral-domain optical coherence tomography revealed a separation between the outer retina and the retinal pigment epithelium within the excavation. In 7 eyes studied with enhanced depth imaging spectral-domain optical coherence tomography, there was no evidence of scleral ectasia. Mean choroidal thickness of the uninvolved choroid was thicker than normal at 319 μm (range, 244-439 μm). All lesions remained stable except for in 1 eye, which had findings of central serous chorioretinopathy and secondary type 2 (subretinal) neovascularization. Focal choroidal excavation is a newly described idiopathic entity in eyes having 1 or more focal areas of choroidal excavation. In some patients, there may be an association with central

  4. Natural course of symptomatic focal choroidal excavation. (United States)

    Pierro, Luisa; Casalino, Giuseppe; Introini, Ugo; Gagliardi, Marco; Sergenti, Jessica; Cascavilla, Maria Lucia; Bandello, Francesco


    A 32-year-old man was referred to the authors' department for nonspecified macular dystrophy with persistent metamorphopsia in the right eye diagnosed 10 years before and followed using optical coherence tomography. The patient underwent a comprehensive ocular examination, including multimodal imaging evaluation and electrofunctional testing. The diagnosis was consistent with nonconforming focal choroid excavation. Over 10 years, no complications occurred, visual acuity was stable, and optical coherence tomography showed no progression of the lesion during follow-up. In this case, nonconforming symptomatic focal choroid excavation was a nonprogressive condition with good long-term visual outcome. Copyright 2015, SLACK Incorporated.

  5. The cubital tunnel: a radiologic and histotopographic study

    National Research Council Canada - National Science Library

    Macchi, Veronica; Tiengo, Cesare; Porzionato, Andrea; Stecco, Carla; Sarasin, Gloria; Tubbs, Shane; Maffulli, Nicola; De Caro, Raffaele


    .... The present study evaluates the anatomy of the cubital tunnel. Eighteen upper limbs were analysed in unembalmed cadavers using ultrasound examination in all cases, dissection in nine cases, and microscopic study in nine cases...

  6. Carpal Tunnel Syndrome (United States)

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

  7. Computational design and analysis of flatback airfoil wind tunnel experiment.

    Energy Technology Data Exchange (ETDEWEB)

    Mayda, Edward A. (University of California, Davis, CA); van Dam, C.P. (University of California, Davis, CA); Chao, David D. (University of California, Davis, CA); Berg, Dale E.


    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.

  8. Strata control in tunnels and an evaluation of support units and systems currently used with a view to improving the effectiveness of support, stability and safety of tunnels.

    CSIR Research Space (South Africa)

    Haile, AT


    Full Text Available This report details a methodology for rational design of tunnel support systems based on a mechanistic evaluation of the interaction between the components of a tunnel support system and a highly discontinuous rock mass structure. This analysis...

  9. Hypersonic aerothermodynamic and scramjet research using high enthalpy shock tunnel (United States)

    Itoh, K.; Ueda, S.; Tanno, H.; Komuro, T.; Sato, K.

    A high enthalpy shock tunnel is a potential facility for gaining knowledge to develop modern aerothermodynamic and propulsion technologies. The largest high enthalpy shock tunnel HIEST was built at NAL Kakuda in 1997, aiming for aerothermodynamic tests of Japan's space vehicle HOPE and scramjet propulsion systems. Selected topics from the experimental studies carried out using HIEST so far, such as the nonequilibrium aerodynamics of HOPE, the surface catalytic effect on aerodynamic heating and scramjet performance are described.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  11. Supervision of tunnelling constructions and software used for their evaluation (United States)

    Caravanas, Aristotelis; Hilar, Matous


    Supervision is a common instrument for controlling constructions of tunnels. In order to suit relevant project’s purposes a supervision procedure is modified by local conditions, habits, codes and ways of allocating of a particular tunnelling project. The duties of tunnel supervision are specified in an agreement with the client and they can include a wide range of activities. On large scale tunnelling projects the supervision tasks are performed by a high number of people of different professions. Teamwork, smooth communication and coordination are required in order to successfully fulfil supervision tasks. The efficiency and quality of tunnel supervision work are enhanced when specialized software applications are used. Such applications should allow on-line data management and the prompt evaluation, reporting and sharing of relevant construction information and other aspects. The client is provided with an as-built database that contains all the relevant information related to a construction process, which is a valuable tool for the claim management as well as for the evaluation of structure defects that can occur in the future. As a result, the level of risks related to tunnel constructions is decreased.

  12. Intrasynovial lipoma causing trigger wrist and carpal tunnel syndrome. (United States)

    Imai, Shinji; Kodama, Narihito; Matsusue, Yoshitaka


    Triggering of the flexor tendon at the wrist is rare. We report a case of intrasynovial lipoma that caused a trigger wrist. As far as we know it is unique in that the intrasynovial lipoma simultaneously caused carpal tunnel syndrome. The massive tenosynovitis and adhesion of flexors tendons after the locking of the intrasynovial lipoma may have resulted from inflammation caused by attrition within the carpal tunnel.

  13. Meaningful use of peak particle velocities at excavation surfaces for the optimisation of the rockburst criteria for tunnels and stopes

    CSIR Research Space (South Africa)

    Cichowicz, A


    Full Text Available ?a@BaE?+#/*32!&9)%#B:E#+)!$&*2,%#?C/c ######M4N#E?#]'6%/=%.#E@@@+#E@aEG+7%*<#3.'92)#/'&!'2^^^^^^^^^^^^^^^^::BF: T!39.%#\\:B:#S%!$/!,#%6%2!&8#/*32!&9)%#E#-',*&%)#C?/#(.'/#$&.'23#3.'92)#/'&!'2#$%2$'.$+ 5.!%('2&%!2#0!2%+#S%1&%/=%.#E_+#E@@@+#B\\aFGaF\\:#",,%-%.'3..."&#"4$)6"*-%(,$E"&3"5<$"<&1<"/)$?2$3*6")+31$= N$4$)+,")$#-3+3*$"($+0#"/)-%"IYYZ["5-"IYYY"Z["*+3"A$"-A#$)4$.="79!8PKY@"A0+93>0+B5%#5-$C""'(((;= U3"+3+,6#$."*+#$#"5<$"+%(,&/&*+5&-3"-/"+"A-.6"B+4$"#&13+,"#5+)5#"/)-%"LY"Z["+3."+%(,&/&*+5&-3"-/"+"#2)/+*$ B+4...

  14. Open microsurgical tumor excavation and vertebroplasty for metastatic destruction of the second cervical vertebra-outcome in seven cases. (United States)

    Floeth, Frank W; Herdmann, Jörg; Rhee, Sascha; Turowski, Bernd; Krajewski, Kara; Steiger, Hans-Jakob; Eicker, Sven O


    Metastatic osteolytic involvement of the second cervical vertebra (C2) is rare, but usually very painful. Percutaneous vertebroplasty has shown to be effective regarding pain control, but carries the risk of cement leakage. To describe an alternative microsurgical procedure suitable for patients suffering from C2 osteolysis who are considered to be high risk with respect to cement leakage. A technical report. It included seven patients. They include the assessment of clinical safety regarding approach- and procedure-related morbidity and radiologic safety regarding extravertebral cement leakage and the assessment of clinical efficacy by monitoring the pain activity using the visual analog scale (VAS). Seven patients (five men, two women; mean age 70 years) presented with an acute onset of excruciating neck pain (VAS>6) due to osteolytic destruction of the axis vertebra. There was no neurologic deficit and no compression of the spinal cord preoperatively requiring surgical decompression or stabilization in any of the cases. An open treatment strategy via an anterolateral microsurgical approach was performed. Under biplanar fluoroscopic control, the soft tumor tissue was resected out of the vertebral body through a drilled entry in the anterior wall. After the excavation procedure, the resection cavity was filled with minimal pressure with polymethylmethacrylate bone cement. All patients suffered from severe spontaneous neck pain (mean VAS 8.1, range 6-9), with head motion-dependent pain exacerbation despite high dose of opiates and fixation of the head with a brace.Mean duration of the operative procedure was 51 minutes. Histologic analysis revealed a diagnosis of cancer metastasis in all cases. On average, 1.9 mL cement was placed within the vertebral body, and no cement leakage was observed in postoperative computed tomography and X-ray controls. All patients experienced immediate pain relief at Day 1 after the procedure (mean VAS 4.0, range 2-6), and a further

  15. Seismic prediction and imaging of geological structures ahead of a tunnel using surface waves


    Jetschny, Stefan


    To improve the performance and safety of tunnel constructions, we introduce a new seismic prediction method utilizing tunnel surface waves to detect relevant geological structures ahead of the tunnel face. On the basis of both synthetic and field data, we investigate the propagation characteristics of such surface waves propagating along the tunnel wall. We further introduce a simple but robust automatic prediction scheme that can estimate the distance to a reflector ahead of the tunnel.

  16. Boring and excavation technologies for Opalinus clay in the rock laboratories at Mont Terri; Techniques de forages et d'excavations dans les argiles à Opalinus, laboratoire souterrain du Mont Terri

    Energy Technology Data Exchange (ETDEWEB)

    Bossart, P.; Nussbaum, Ch. [Swiss Federal Office of Topography swisstopo, Wabern (Switzerland); Burrus, F. [Groupe Grands Travaux GGT, Porrentruy (Switzerland)


    This comprehensive article discusses the work done since 1996 at the rock laboratories at Mont Terri in the Swiss Jura Mountains. The work being done by fifteen international partners on the characterisation of the Opalinus clay with regard to its geological, hydro-geological, geochemical and geotechnical characteristics is reported on. Various methods of drilling are described that are able to preserve any tectonic crevices in the rock. Drilling under special conditions, including the use of nitrogen and argon atmospheres to prevent bacterial contamination, is looked at, as are the methods used in tunnelling without having to use water.


    Directory of Open Access Journals (Sweden)

    Yang Chengzhong


    Full Text Available With a lot construction of transportation infrastructure in Chinese mountainous area, because of its unique advantages such as less land occupation, beautiful appearance and convenient route planning, small spacing tunnels are widely used. The shallow buried tunnel with small spacing, the blasting excavation will lead to tunnel surrounding rock especially in the middle rock wall damage and reduce the self-bearing capacity of surrounding rock. Through detecting and analyzing by the geological radar of the excavated red layer soft rock tunnel surrounding rock found that the middle rock wall loose circle thickness of the tunnel reaches to 1.8 m, the vault and sidewall loose circle thickness is about 1.2 m. Through selection of rational strengthening measures and blasting design scheme to improve drilling parameters and methods, as far as possible to protect the integrity and self-bearing capacity of the surrounding rock, the deformation and vibration of the tunnel would be controlled in reasonable limits and ensure the safety of tunnel construction.

  18. Fermi-edge singularity at tunneling and anisotropic magneto-tunneling in low-dimensional semiconductor structures

    Energy Technology Data Exchange (ETDEWEB)

    Larkin, Ivan A [International Institute of Physics (IIP), Universidade Federal do Rio Grande do Norte, Departamento de Fisica, Campus Universitario Lagoa Nova, Natal, RN, 59078-970 (Brazil); Vdovin, E E; Khanin, Yu N [Institute of Microelectronics Technology RAS, 142432 Chernogolovka (Russian Federation); Ujevic, Sebastian [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Santo Andre, Sao Paulo 09210-170 (Brazil); Henini, M, E-mail: [School of Physics and Astronomy, University of Nottingham, NG7 2RD (United Kingdom)


    We consider many-body enhanced electron tunneling through an InAs quantum dot in a magnetic field applied perpendicular to the tunneling direction. The critical exponent of the Fermi-edge singularity in the tunneling current is calculated as a function of the magnetic field. We use lowest Landau level approximation for the electrons in the emitter and perform scattering matrix calculations using the Born approximation. We examine in detail the anisotropic behavior of the amplitude and shape of the resonant peaks.

  19. Excavation costs for lunar materials (United States)

    Carrier, W. D., III


    A lunar strip mining system is presented which is capable of excavating and transporting 3 million metric tons of ore per year to a central processing plant on the moon's surface. The mining system would grow from a single front-end loader in the first year, to a fleet of ten haulers in the 30th year. Lunar personnel requirements would consist of a single individual, whose primary function would be to perform maintenance. All of the mining equipment would either operate automatically or by remote control from earth. The projected cost for the lunar mining system is approximately $12 to $37 per ton of ore over the life of the mine, an important part of the overall economics of exploiting lunar resources.

  20. The analysis of creep characteristics of the surrounding rock of the carbonaceous rock tunnel based on Singh-Mitchell model (United States)

    Luo, Junhui; Mi, Decai; Ye, Qiongyao; Deng, Shengqiang; Zeng, Fuquan; Zeng, Yongjun


    Carbonaceous rock has the characteristics of easy disintegration, softening, swelling and environmental sensitivity, which belongs to soft surrounding rock, and the deformation during excavation and long-term stability of the surrounding rock of carbonaceous rock tunnel are common problems in the construction of carbonaceous rock tunnel. According to the above, the Monitor and measure the displacement, temperature and osmotic pressure of the surrounding carbonaceous rock of the tunnel of Guangxi Hebai highway. Then it based on the obtaining data to study the creep mechanism of surrounding rock using Singh-Mitchell model and predict the deformation of surrounding rock before the tunnel is operation. The results show that the Singh-Mitchell creep model can effectively analyse and predict the deformation development law of surrounding rock of tunnel without considering temperature and osmotic pressure, it can provide reference for the construction of carbonaceous rock tunnel and the measures to prevent and reinforce it..

  1. Influence of Guidelines and Passageways on Tunneling Behavior of Reticulitermes flavipes (Kollar) and R, virginicus (Banks) (Isoptera: Rhinotermitidae) (United States)

    Theresa L. Pitts-Singer; Brian T. Forschler


    Tunneling behavior of laboratory-maintained cultures of Reticulitermes flavipes (Kollar) and R. virginicus (Banks) was examined to determine (1) if the termites build tunnels along preexisting wires or tunnels, and (2) whether tunnels are arranged, to optimize search efficiency. Tunnel patterns were considered optimal if ,...

  2. Heathrow Terminal 5 Excavation Archive (Data Paper

    Directory of Open Access Journals (Sweden)

    Framework Archaeology


    Full Text Available Framework Archaeology is a Joint Venture agreement between Oxford Archaeology (OA and Wessex Archaeology (WA to provide archaeological services to BAA (formerly British Airports Authority, now Heathrow Airport Holdings Ltd. Given the potential scale of some of BAA's projects, the joint venture enables Framework Archaeology to draw on the full resources of both OA and WA, including site staff, specialist managers, administrative support, and technical facilities. In 1993, BAA plc and Heathrow Airport Limited submitted a joint planning application to develop an additional passenger terminal complex (Terminal 5, together with the provision of aircraft aprons and taxiways, and include the realignment of rivers and landscaping. The resulting archaeological excavations were undertaken as three main phases of work. Excavations in 1996 by the Museum of London Archaeology Service of approximately 4 ha of sludge stockpile areas (site code POK96. Between 1999-2000 Framework Archaeology excavated approximately 21 ha in the Perry Oaks sludge works and adjacent areas (WPR98. Framework Archaeology also undertook excavations between 2002-2007 as part of the construction of Terminal 5 (PSH02, TEC05 covering a further 50 hectares. Importantly the aim of the Terminal 5 archaeological programme was to move beyond the description and recovery of archaeological remains and to arrive at an understanding of the history of human inhabitation and the practical ways in which people established their presence in the material, social and political conditions of their day.

  3. Rediscovering Antiquity: Karl Weber and the Excavation of Herculaneum, Pompeii, and Stabiae, by C.C. Parslow. Cambridge University Press, 1995

    Directory of Open Access Journals (Sweden)

    James E. Snead


    Full Text Available Rediscovering Antiquity is an example of the genre of historical writing which seeks to recast the careers of little-known figures who have fallen into obscurity. This is typically intended to move them and their work into the proper "lineage," that is, the select group of ancestral figures from which modern practices are derived. Parslow is interested in the 18th century excavations of the Vesuvian cities, which, he argues, have been misunderstood by historians of archaeology. Indeed, common sources, such as Daniel (1981:55, describe the initial explorations of Pompeii, Herculaneum, and Stabiae, sponsored by the Bourbon kings of Naples as "...treasure hunts and not serious excavations." While the Roman artifacts removed from the sites are credited with spurring interest in antiquity in Enlightenment Europe, modern scholars have until now devoted little attention to the means through which they were recovered.

  4. Fractal characteristics of seismic process in rock mass surrounding the excavation at mining. Mathematical modelling and analysis (United States)

    Eremin, M. O.; Makarov, P. V.


    It is shown in the paper that the system of equations of solid mechanics, which has a mixed type, demonstrate the most common features of evolution of nonlinear dynamic systems. Previous investigations of seismic process were carried out on the base of simplified (sand-pile, land-slide) models which gave a graph of recurrence of seismic events and information about the state of self-organized criticality (SOC). However, these simplified models do not contain the information about the stress-strain state of the loaded geomedia and its proximity to the critical state. In the proposed paper the model of rock mass with excavation is constructed and general step of roof caving is modelled. On the base of these modelling the formation of critical state in loaded geomedia is studied. The fluctuations of stress-strain state at different points of geomedia are studied as the reflection of fracture process occurring in the main elements of rock mass: roof and floor, when the coal face is advanced. It is shown that the PDF dependencies, amplitude-frequency characteristics reflect the state of the rock mass and might be considered as the fractal characteristics of fracture process within. The evolution of these dependencies shows the dramatic change when the critical state is formed in the rock mass surrounding the underground opening.

  5. Geotechnical investigation and static analysis of deep excavation walls – a case study of metro station construction in Warsaw

    Directory of Open Access Journals (Sweden)

    Mitew-Czajewska Monika


    Full Text Available The paper presents detailed analysis of the case – a construction of deep excavation of metro station in Warsaw. Basing on this example, the great impact of the accuracy of the geotechnical investigation on the static analysis of diaphragm walls is discussed. Geotechnical studies for the construction of the central section of the second metro line were carried out in stages. Basic geotechnical soil investigation took place in the first stage of investment process, e.g. building permit and tender design stages in 2003–2004, 2007 and 2010. In subsequent years, complementary soil investigations have been performed by the contractor, and the results occurred to differ significantly. In the first part of the paper detailed description of the case is introduced. The geological conditions in the area of the station and the interpretation of the results of the three successive stages of geotechnical investigation are presented. As a result, two locations were selected with a great diversity of the soil profile depending on the stage of investigation. For each location, detailed, multiple static analysis of diaphragm walls were performed, taking into account changes in the soil profile. In the paper, one selected location is described in detail. The discussion of calculation results for this location in relation to the changing geotechnical data is presented and final conclusions are provided.

  6. Dilmun revisited: excavations at Saar, Bahrain

    Directory of Open Access Journals (Sweden)

    Harriet Crawford


    Full Text Available About 2000 BC the island of Bahrain was at the centre of a prosperous trading community - the Early Dilmun civilization - that stretched from Mesopotamia to the Indus Valley. Excavations at the site of Saar have, since 1989, recovered much new information about the layout of the settlement and its local economy and social system.

  7. Excavated Documents Dealing with Chinese Astronomy (United States)

    Guan, Yuzhen

    The materials ancient Chinese scholars used to write on changed from bamboo strips, wooden tablets, and silk in early China to paper in the later dynasties. This chapter will focus on excavated documents dealing with ancient Chinese astronomy and explore some of the ways that scholars have made use of these archaeological resources.

  8. Assessment of pile response due to deep excavation in close proximity—A case study based on DTL3 Tampines West Station

    Directory of Open Access Journals (Sweden)

    C.G. Chinnaswamy


    Full Text Available Ground movements during deep excavations and tunnelling, especially in urban areas, may potentially have major impact on adjacent buildings, structures and utilities. This impact on buildings and structures needs to be assessed by considering the horizontal and vertical displacements induced by deep excavations to determine the necessary mitigation measures. One major factor affecting the degree of severity the impact due to deep excavation may have on the buildings and structures is the type of foundation systems. While methodology in determining the damage category for the buildings on shallow foundation has been quite well established, the methodology for assessing the impact on the pile foundation is not straightforward due to the geometry and complexity of soil structure interaction. Often simplified two-dimensional (2D or comprehensive three-dimensional (3D finite element analyses would be carried out for the stage excavation to predict the displacement and stresses in the piles. Suitable protective and preventive measures would need to be designed and implemented for the existing buildings/structures if the damage category falls within the unacceptable range. This paper discusses the analysis and methodology to assess the effect on the pile foundation of a high-rise building due to the deep excavation of the Down Town Line Stage 3 (DTL3 Tampines West (TPW Station. The approach to assess the geotechnical capacity of the pile as a result of the deep excavation is presented in this paper. Based on the assessment of pile response, predicted movement, structural and geotechnical capacities of the pile, it was found to be within the acceptable limit and the pile foundation has adequate factor of safety with the deep excavation in close proximity.

  9. Reducing Extra-Terrestrial Excavation Forces with Percussion (United States)

    Mueller, Robert; Schuler, Jason M.; Smith, Jonathan Drew; Nick, Andrew J.; Lippitt, Thomas


    High launch costs and mission requirements drive the need for low mass excavators with mobility platforms, which in turn have little traction and excavation reaction capacity in low gravity environments. This presents the need for precursor and long term future missions with low mass robotic mining technology to perform In-Situ Resource Utilization (ISRU) tasks. This paper discusses a series of experiments that investigate the effectiveness of a percussive digging device to reduce excavation loads and thereby the mass of the excavator itself. A percussive mechanism and 30" wide pivoting bucket were attached at the end of the arm simulating a basic backhoe with a percussion direction tangent to the direction of movement. Impact energies from 13.6J to 30.5J and frequencies from 0 BPM to 700 BPM were investigated. A reduction in excavation force of as much as 50% was achieved in this experimental investigation.

  10. The effect of caries excavation methods on the bond strength of etch-and-rinse and self-etch adhesives to caries affected dentine. (United States)

    Aggarwal, V; Singla, M; Yadav, S; Yadav, H


    The aim of this study was to evaluate the influence of chemomechanical caries removal and conventional caries excavation on the microtensile bond strength of three different dentine adhesive systems. Thirty extracted human mandibular molars with radiographic signs of dental caries extending up to the middle third of dentine were sectioned longitudinally through the centre of the carious lesion in a buccolingual direction to yield two sections. One half of each tooth was excavated by tungsten carbide bur and the other half was chemomechanically treated with Carisolv(®) . Three dentine bonding systems: an etch-and-rinse single bottle adhesive (Single Bond, 3M ESPE); a two bottle, two-step self-etch bonding system (One Coat Self Etching Bond, Coltene Whaledent); and a single-step, single bottle self-etch adhesive (Adper Easy Bond Self-Etch Adhesive, 3M ESPE) were applied and composite build-up was done. The specimens were tested for microtensile bond strength. Data were analysed using two-way analysis of variance and pair-wise multiple comparisons were done using the Holm-Sidak method. The etch-and-rinse adhesive and two bottle self-etch system showed significantly higher bond strength than the single bottle self-etch system. Caries excavation method had no influence on bond strength values. Carisolv(®) did not affect the microtensile bond strength values of different adhesive systems tested to the caries affected dentine. © 2013 Australian Dental Association.

  11. Archaeological Rescue Excavations at the Dejazmach Gebreslassie ...

    African Journals Online (AJOL)

    Archaeological rescue test excavations that were carried out by the Ethiopian Cultural Heritage Project Site Planning and Conservation sub-component at the Gebreslassie Bariya Gabir palace enclosure at the back of The Main Stelae Field in Aksum from the 5th of June to the 15th of July 2005 yielded at least four ...

  12. Wear model of an excavator bucket (United States)

    Sarychev, Vladimir D.; Granovskii, Alexey Yu.; Nevskii, Sergey A.; Konovalov, Sergey V.; Gromov, Victor E.


    A mathematical model describing wear of the interior faces of the excavator bucket during the long-termed operation is proposed. The model is based on the Navier-Stocks equation and boundary conditions. The bucket was modeled as a rectangular parallelepiped; one of its faces is permeable for a granular material, whereas the others meet the conditions of impermeability and adhesion. In the approximation of viscous fluid, motion equations of a granular material in the excavator bucket were solved by the finite elements method. The velocity distribution curves of material particles along the bucket surface are obtained. A vortex structure is revealed at the bottom-back wall edge of the bucket, and it is thought to be the reason for high wear in these zones. As shown by the granular material pressure distributed along the bucket walls, its maximum is at the bottom-back wall edge of the excavator bucket. It is considered to be the reason for high wear in the operation process. Therefore, the bottom and back walls of the excavator bucket should be coated with a composite armouring mesh via arc surfacing.

  13. The Emergent Universe scheme and tunneling

    Energy Technology Data Exchange (ETDEWEB)

    Labraña, Pedro [Departamento de Física, Universidad del Bío-Bío, Avenida Collao 1202, Casilla 5-C, Concepción, Chile and Departament d' Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos, Universitat (Spain)


    We present an alternative scheme for an Emergent Universe scenario, developed previously in Phys. Rev. D 86, 083524 (2012), where the universe is initially in a static state supported by a scalar field located in a false vacuum. The universe begins to evolve when, by quantum tunneling, the scalar field decays into a state of true vacuum. The Emergent Universe models are interesting since they provide specific examples of non-singular inflationary universes.

  14. Sibudu Cave, KwaZulu-Natal: Background to the excavations of middle stone age and iron age occupations

    CSIR Research Space (South Africa)

    Wadley, L


    Full Text Available Sibudu Cave excavations have yielded an Iron Age occupation directly overlying a long sequence of final Middle Stone Age (MSA)layers dating c. 61 000–26 000 years ago. Older, undated layers contain a Howiesons Poort Industry. A diverse animal...

  15. MgGa2O4 spinel barrier for magnetic tunnel junctions: Coherent tunneling and low barrier height (United States)

    Sukegawa, Hiroaki; Kato, Yushi; Belmoubarik, Mohamed; Cheng, P.-H.; Daibou, Tadaomi; Shimomura, Naoharu; Kamiguchi, Yuuzo; Ito, Junichi; Yoda, Hiroaki; Ohkubo, Tadakatsu; Mitani, Seiji; Hono, Kazuhiro


    Epitaxial Fe/magnesium gallium spinel oxide (MgGa2O4)/Fe(001) magnetic tunnel junctions (MTJs) were fabricated by magnetron sputtering. A tunnel magnetoresistance (TMR) ratio up to 121% at room temperature (196% at 4 K) was observed, suggesting a TMR enhancement by the coherent tunneling effect in the MgGa2O4 barrier. The MgGa2O4 layer had a spinel structure and it showed good lattice matching with the Fe layers owing to slight tetragonal lattice distortion of MgGa2O4. Barrier thickness dependence of the tunneling resistance and current-voltage characteristics revealed that the height of the MgGa2O4 barrier is much lower than that of an MgAl2O4 barrier. This study demonstrates the potential of Ga-based spinel oxides for MTJ barriers having a large TMR ratio at a low resistance area product.

  16. Concomitant endoscopic carpal and cubital tunnel release: safety and efficacy. (United States)

    Cross, Danielle; Matullo, Kristofer S


    When performed alone, endoscopic carpal tunnel release and endoscopic cubital tunnel release are safe and effective surgical options for the treatment of carpal and cubital tunnel syndromes, respectively. However, there is currently no literature that describes the performance of both procedures concomitantly. We describe the results of 17 cases in which dual endoscopic carpal and cubital tunnel releases were performed for the treatment of concurrent carpal and cubital tunnel syndromes. A retrospective review of all patients in a single surgeon practice that presented with concomitant ipsilateral carpal and cubital tunnel syndromes was performed. Within an 8-month period, 17 patients had undergone 19 concomitant ipsilateral endoscopic carpal and cubital tunnel releases after failing conservative treatment. Pre- and postoperative measurements included subjective numbness/tingling; subjective pain; manual muscle testing of the abductor pollicis brevis (APB), intrinsics, and flexor digitorum profundus (FDP); static two-point discrimination; quick-DASH (Disabilities of the Arm, Shoulder and Hand) scores; grip strength; chuck pinch strength; and key pinch strength. Complete data are available for 15 patients and 17 total procedures. Thirteen male and four female patients (average age of 50.5) underwent dual endoscopic cubital and carpal tunnel release. Two patients were lost to follow-up and eliminated from data analysis. Pre- and postoperative comparisons were completed for median DASH scores, grip strength, chuck pinch strength, and key pinch strength at their preoperative visit and at 12 weeks. DASH scores improved significantly from a median of 67.5 to 16 (p = 0.002), grip strengths improved from 42 to 55.0 lbs (p = 0.30), chuck pinch strengths improved significantly from 11 to 15.5 lbs (p = 0.02), and key pinch strengths increased significantly from 13 to 18 lbs (p = 0.003). Average static two-point discrimination decreased from 5.9 to 4.8

  17. Enzyme Tunnels and Gates As Relevant Targets in Drug Design. (United States)

    Marques, Sergio M; Daniel, Lukas; Buryska, Tomas; Prokop, Zbynek; Brezovsky, Jan; Damborsky, Jiri


    Many enzymes contain tunnels and gates that are essential to their function. Gates reversibly switch between open and closed conformations and thereby control the traffic of small molecules-substrates, products, ions, and solvent molecules-into and out of the enzyme's structure via molecular tunnels. Many transient tunnels and gates undoubtedly remain to be identified, and their functional roles and utility as potential drug targets have received comparatively little attention. Here, we describe a set of general concepts relating to the structural properties, function, and classification of these interesting structural features. In addition, we highlight the potential of enzyme tunnels and gates as targets for the binding of small molecules. The different types of binding that are possible and the potential pharmacological benefits of such targeting are discussed. Twelve examples of ligands bound to the tunnels and/or gates of clinically relevant enzymes are used to illustrate the different binding modes and to explain some new strategies for drug design. Such strategies could potentially help to overcome some of the problems facing medicinal chemists and lead to the discovery of more effective drugs. © 2016 Wiley Periodicals, Inc.

  18. Free Spaces: Excavating Race, Class, and Gender among Urban Schools and Communities (United States)

    Akom, A. A.


    This article introduces the concept of "free spaces" as an important site for the development of theory and practice around youth activism, teacher development, and the transformation of public and private space in urban schools and communities. Nearly a quarter of a century ago, Evans and Boyte (1986) introduced the concept of "free spaces" in…

  19. Enigma of scapular foramen and tunnels: an untold story. (United States)

    Singh, Nidhi; Chauhan, Puja; Loh, Hitendra Kumar; Kohli, Mangala; Suri, Rajesh Kumar


    The study was undertaken to make a qualitative and quantitative assessment of unnamed foramen and tunnels in adult human scapulae with aid of plain and contrast radiographs. A total of 120 dry bones, 60 each of the right and the left side were included in the study. Distribution of these foramina and tunnels was noted for their number, side, location, course and communication. Their morphometry was done using Vernier's caliper. Incidence of scapular foramina was 7.5% (R > L), whereas scapular tunnels were seen in 15.8% cases. Incidence of the sinuous, curved, and straight tunnels was found to be 50, 39, and 10.7% respectively. Left-sided tunnels were longer than the right ones. Plain and contrast radiographs were taken to confirm the findings. Anatomy literature describes only two scapular foramina, namely, nutrient foramen and suprascapular foramen/notch in a great zeal; occurrence of such anonymous foramina is hardly discussed. Through this study, there is an endeavor towards unfolding the mystery of scapular foramina in terms of their morphometry and distribution, the knowledge of which will aid clinicians, forensic experts, and surgeons in better diagnosis and management of clinical cases.

  20. Joint road safety operations in tunnels and open roads (United States)

    Adesiyun, Adewole; Avenoso, Antonio; Dionelis, Kallistratos; Cela, Liljana; Nicodème, Christophe; Goger, Thierry; Polidori, Carlo


    The objective of the ECOROADS project is to overcome the barrier established by the formal interpretation of the two Directives 2008/96/EC and 2004/54/EC, which in practice do not allow the same Road Safety Audits/Inspections to be performed inside tunnels. The projects aims at the establishment of a common enhanced approach to road infrastructure and tunnel safety management by using the concepts and criteria of the Directive 2008/96/CE on road infrastructure safety management and the results of related European Commission (EC) funded projects. ECOROADS has already implemented an analysis of national practices regarding Road Safety Inspections (RSI), two Workshops with the stakeholders, and an exchange of best practices between European tunnel experts and road safety professionals, which led to the definition of common agreed safety procedures. In the second phase of the project, different groups of experts and observers applied the above common procedures by inspecting five European road sections featuring both open roads and tunnels in Belgium, Albania, Germany, Serbia and Former Yugoslav Republic of Macedonia. This paper shows the feedback of the 5 joint safety operations and how they are being used for a set of - recommendations and guidelines for the application of the RSA and RSI concepts within the tunnel safety operations.

  1. Short report on the excavations in 2014 of the Department of Hungarian Medieval and Early Modern Archaeology (Eötvös Loránd University, Budapest. Excavations at Castles Čabraď and Drégely, and at the Pauline Friary at Sáska

    Directory of Open Access Journals (Sweden)

    Maxim Mordovin


    Full Text Available The Department of Hungarian Medieval and Early Modern Archaeology carried out three excavations in 2014, including two castles (Drégely and Čabraď and a monastic site (Sáska – Bakonyszentjakab. The first two provided mainly early modern material, while the last one existed from the 13th until the mid-16th century.

  2. Measurements and computations of second-mode instability waves in three hypersonic wind tunnels.

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Daniel R. (Aerospace Testing Alliance, Silver Spring, MD); Alba, Christopher R. (Air Force Research Laboratory, Wright-Patterson AFB, OH); Rufer, Shann J. (NASA Langley Research Center, Hampton, VA); Beresh, Steven Jay; Casper, Katya M.; Berridge, Dennis C. (Purdue University, West Lafayette, IN); Schneider, Steven P. (Purdue University, West Lafayette, IN)


    High-frequency pressure-fluctuation measurements were made in AEDC Tunnel 9 at Mach 10 and the NASA Langley 15-Inch Mach 6 and 31-Inch Mach 10 tunnels. Measurements were made on a 7{sup o}-half-angle cone model. Pitot measurements of freestream pressure fluctuations were also made in Tunnel 9 and the Langley Mach-6 tunnel. For the first time, second-mode waves were measured in all of these tunnels, using 1-MHz-response pressure sensors. In Tunnel 9, second-mode waves could be seen in power spectra computed from records as short as 80 {micro}s. The second-mode wave amplitudes were observed to saturate and then begin to decrease in the Langley tunnels, indicating wave breakdown. Breakdown was estimated to occur near N {approx} 5 in the Langley Mach-10 tunnel. The unit-Reynolds-number variations in the data from Tunnel 9 were too large to see the same processes.

  3. (Re)Membering: Excavating and Performing Uncommon Narratives Found in Archives and Historical Societies (United States)

    Kemp, Amanda; Parrish, Marilyn McKinley


    Through in-depth research into the lives of African Americans, playwright Dr. Amanda Kemp critically engages the narratives, texts, and stories that are often lost within dominant community and national narratives. The framework for her work is Black feminism and performance theory. Kemp and her drama group, Theatre for Transformation, produce…

  4. Electric and VLF-MT survey of Tegatayama tunnel; Tegatayama tunnel no denki tansa oyobi VLF tansa

    Energy Technology Data Exchange (ETDEWEB)

    Nishitani, T. [Akita University, Akita (Japan). Mining College


    To survey the structure at the depth between 20 and 30 m, field tests were conducted by means of vertical electric and VFL-MT (magnetotelluric) survey. Tegatayama tunnel has a total length of 276 m, width of 7.5 m, and height of 4.7 m, and the depth from the surface is about 28 m near the top of mountain. Near the tunnel, the thickness of surface soil is about 60 cm, which consists of clay soil including soft mudstone gravel. It was found that terrace deposit is distributed up to the depth of 8 m, and that mudstone is distributed below the depth of 8 m. Weighted four-electrode method was adopted for the vertical electrical survey. Measurements were conducted at the immediately above the tunnel, 10 m apart from the center of tunnel in the right and left, and 20 m apart from the center in the east. For the VLF-MT method, component of frequency 22.2 kHz was used. As a result of the tests, it was difficult to illustrate the existence of tunnel from the vertical electrical survey only at one point. Feature of the tunnel could be well illustrated by means of the VLF-MT method. 3 refs., 9 figs.

  5. Exploration and excavation of shipwrecks in Goa and adjoining waters 2004-2005

    Digital Repository Service at National Institute of Oceanography (India)


    little elavated. Iron guns and granite stone blocks located earlier were also noticed. The wreck remains has been scattered over 75 to 100 m on the east, northeast and northwest side of the guns but not much artefacts noticed on southern and western sides....

  6. A Numerical Comparison of Symmetric and Asymmetric Supersonic Wind Tunnels (United States)

    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

  7. Modelling of blast-induced damage in tunnels using a hybrid finite-discrete numerical approach

    Directory of Open Access Journals (Sweden)

    Amichai Mitelman


    Full Text Available This paper presents the application of a hybrid finite-discrete element method to study blast-induced damage in circular tunnels. An extensive database of field tests of underground explosions above tunnels is used for calibrating and validating the proposed numerical method; the numerical results are shown to be in good agreement with published data for large-scale physical experiments. The method is then used to investigate the influence of rock strength properties on tunnel durability to withstand blast loads. The presented analysis considers blast damage in tunnels excavated through relatively weak (sandstone and strong (granite rock materials. It was found that higher rock strength will increase the tunnel resistance to the load on one hand, but decrease attenuation on the other hand. Thus, under certain conditions, results for weak and strong rock masses are similar.

  8. [Characteristic and treatment of acute aggravating cubital tunnel syndrome]. (United States)

    Chen, Ran; Kan, Shilian; Li, Jin


    To investigate the causes and the characteristics of acute aggravating cubital tunnel syndrome. The enrolling criteria of subjects were as follows: (1) Patients with manifestation of cubital tunnel syndrome for more than 6 months; (2) acute exacerbation of the disease for no more than 4 weeks. The clinical data from March 2011 to December 2014 was collected and analyzed retrospectively. Twelve cases aged 52 to 65 met the enrolling criteria and were included in this study, and among them 10 patients were male, 2 were female; 5 cases were on the left and the other 7 on the right. All of them had some degree of cubital tunnel syndrome symptoms before the onset of acute exacerbation. When nerve decompression and anterior transposition of the ulnar nerve was performed, the elbow joint cysts which squeezed the ulnar nerve were found. The cysts were then resected. In all 12 cases, the compression symptoms of ulnar nerve were relieved after surgery. The mean follow up period was 13 months, ranging from 6 to 45 months. According to Gu Yudong functional evaluation criteria for cubital tunnel syndrome, 2 of the patients can be judged as "Excellent", 8 "good" and 2 "acceptable" at the follow-up. Cyst compression may induce the acute exacerbation of ulnar nerve symptom in patients with cubital tunnel syndrome. Early diagnosis and treatment is critical for these patients.

  9. Tunneling Time and Weak Measurement in Strong Field Ionization (United States)

    Zimmermann, Tomáš; Mishra, Siddhartha; Doran, Brent R.; Gordon, Daniel F.; Landsman, Alexandra S.


    Tunneling delays represent a hotly debated topic, with many conflicting definitions and little consensus on when and if such definitions accurately describe the physical observables. Here, we relate these different definitions to distinct experimental observables in strong field ionization, finding that two definitions, Larmor time and Bohmian time, are compatible with the attoclock observable and the resonance lifetime of a bound state, respectively. Both of these definitions are closely connected to the theory of weak measurement, with Larmor time being the weak measurement value of tunneling time and Bohmian trajectory corresponding to the average particle trajectory, which has been recently reconstructed using weak measurement in a two-slit experiment [S. Kocsis, B. Braverman, S. Ravets, M. J. Stevens, R. P. Mirin, L. K. Shalm, and A. M. Steinberg, Science 332, 1170 (2011)]. We demonstrate a big discrepancy in strong field ionization between the Bohmian and weak measurement values of tunneling time, and we suggest this arises because the tunneling time is calculated for a small probability postselected ensemble of electrons. Our results have important implications for the interpretation of experiments in attosecond science, suggesting that tunneling is unlikely to be an instantaneous process.

  10. Clinical classification and treatment of cubital tunnel syndrome. (United States)

    Qing, Cui; Zhang, Jianhua; Wu, Shidong; Ling, Zhao; Wang, Shuanchi; Li, Haoran; Li, Haiqing


    The aim of the present study was to investigate a new clinical classification of cubital tunnel syndrome that provides an improved basis for the clinical diagnosis and treatment of the disease. Retrospective analysis was performed on 341 patients with cubital tunnel syndrome. Based on the etiology, signs and symptoms, neurophysiological tests and computed tomography (CT) imaging, a new clinical classification was proposed. The patients enrolled in the study were treated according to the new classification. According to the new classification, cubital tunnel syndrome cases were divided into types I-IV. Treatment for patients with type I consisted of rest, immobilization or physiotherapy, while patients with type II received simple ulnar neurolysis. Type III patients underwent ulnar neurolysis with expansion of the ulnar nerve sulcus or ulnar nerve anterior transposition surgery. Type IV patients represented a subgroup of cubital tunnel syndrome cases caused by factors other than degenerative joint diseases, including cysts, tumors, traumatic fracture, deformity and elbow deformity. Patients of this type received appropriate surgical treatment according to the specific etiology. Based on previous classifications that relied on sensation and strength symptoms, a new clinical classification of elbow tunnel syndrome has been established in the present study that adopts a CT imaging evaluation index. The new classification is reasonable, simple and practical, and therapies based on this classification are more targeted than those based on previous classifications.

  11. Tunneling times in bianisotropic, dispersive and absorptive metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Radosavljević, Sanja [School of Electrical Engineering, University of Belgrade, Bulevar kralja Aleksandra 73, 11120 Belgrade (Serbia); Photonics Research Group, Ghent University – imec, Sint-Pietersnieuwstraat 41, 9000 Ghent (Belgium); Radovanović, Jelena, E-mail: [School of Electrical Engineering, University of Belgrade, Bulevar kralja Aleksandra 73, 11120 Belgrade (Serbia); Milanović, Vitomir [School of Electrical Engineering, University of Belgrade, Bulevar kralja Aleksandra 73, 11120 Belgrade (Serbia)


    Tunneling times in complex bianisotropic materials have been examined in detail, with absorption and dispersion taken into account. Tunneling is characterized by the dwell and the phase tunneling time. In this paper, we have developed a theoretical model and derived the appropriate expressions for each of these quantities, as well as a relationship between them and the corresponding expression for the energy density. The model has been verified through numerical calculations based on experimental data. We have distinguished cases in which the phases of transmitted and incident wave match each other, and showed that for small angles of incidence, the time that the wave spends inside the barrier can be approximated as a linear function of the barrier width. The Hartman effect has been detected, although for very thick layers of metamaterial. - Highlights: • We analyze the tunneling times in bianisotropic, dispersive and absorptive metamaterials. • Conditions of zero phase tunneling time are identified for a range of frequencies of interest. • The Hartman effect has been detected for very thick barriers of metamaterial.

  12. Tunnelling anomalous and planar Hall effects (Conference Presentation) (United States)

    Matos-Abiague, Alex; Scharf, Benedikt; Han, Jong E.; Hankiewicz, Ewelina M.; Zutic, Igor


    We theoretically show how the interplay between spin-orbit coupling (SOC) and magnetism can result in a finite tunneling Hall conductance, transverse to the applied bias. For two-dimensional tunnel junctions with a ferromagnetic lead and magnetization perpendicular to the current flow, the detected anomalous Hall voltage can be used to extract information not only about the spin polarization but also about the strength of the interfacial SOC. In contrast, a tunneling current across a ferromagnetic barrier on the surface of a three-dimensional topological insulator (TI) can induce a planar Hall response even when the magnetization is oriented along the current flow[1]. The tunneling nature of the states contributing to the planar Hall conductance can be switched from the ordinary to the Klein regimes by the electrostatic control of the barrier strength. This allows for an enhancement of the transverse response and a giant Hall angle, with the tunneling planar Hall conductance exceeding the longitudinal component. Despite the simplicity of a single ferromagnetic region, the TI/ferromagnet system exhibits a variety of functionalities. In addition to a spin-valve operation for magnetic sensing and storing information, positive, negative, and negative differential conductances can be tuned by properly adjusting the barrier potential and/or varying the magnetization direction. Such different resistive behaviors in the same system are attractive for potential applications in reconfigurable spintronic devices. [1] B. Scharf, A. Matos-Abiague, J. E. Han, E. M. Hankiewicz, and I. Zutic, arXiv:1601.01009 (2016).

  13. Excavating the Nation: Archaeology and Control of the Past and Present in Republican Sichuan (United States)

    Kyong-McClain, Jeffrey


    This dissertation considers whether or not archaeology was an effective tool for nation-building elites in Republican China (1912-1949), by looking at the discipline's fortunes in the off-center locale of Sichuan province. Through consideration of the multiplicity of agents and motives involved in archaeological enterprise in Republican Sichuan,…

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

    Energy Technology Data Exchange (ETDEWEB)

    Cubukcu, M.; Laczkowski, P.; Vergnaud, C.; Marty, A.; Attané, J.-P.; Notin, L.; Vila, L., E-mail:; Jamet, M. [University Grenoble Alpes, CEA, INAC-SP2M, F-38054 Grenoble (France); Martin, M.-B.; Seneor, P.; Anane, A.; Deranlot, C.; Fert, A. [Unité Mixte de Physique CNRS-Thales, F-91767 Palaiseau (France); Auffret, S. [University Grenoble Alpes, CNRS, CEA, INAC-SPINTEC, Grenoble F-38054 (France); Ducruet, C. [Crocus Technology, 4 place Robert Schuman, 38000 Grenoble (France)


    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.

  15. Between Tunnel Vision and a Sliding Scale: Power, Normativity and ...

    African Journals Online (AJOL)

    Between Tunnel Vision and a Sliding Scale: Power, Normativity and Justice in the Praxis of the International Criminal Court. Obiora Chinedu Okafor* and. Uchechukwu Ngwaba**. Abstract. This article examines the relatively extensive, liberal and increasing deployment of the International Criminal Court (ICC) as the central ...

  16. The cubital tunnel: a radiologic and histotopographic study. (United States)

    Macchi, Veronica; Tiengo, Cesare; Porzionato, Andrea; Stecco, Carla; Sarasin, Gloria; Tubbs, Shane; Maffulli, Nicola; De Caro, Raffaele


    Entrapment of the ulnar nerve at the elbow is the second most common compression neuropathy in the upper limb. The present study evaluates the anatomy of the cubital tunnel. Eighteen upper limbs were analysed in unembalmed cadavers using ultrasound examination in all cases, dissection in nine cases, and microscopic study in nine cases. In all cases, thickening of the fascia at the level of the tunnel was found at dissection. From the microscopic point of view, the ulnar nerve is a multifascicular trunk (mean area of 6.0 ± 1.5 mm(2) ). The roof of the cubital tunnel showed the presence of superimposed layers, corresponding to fascial, tendineous and muscular layers, giving rise to a tri-laminar structure (mean thickness 523 ± 235 μm). This multilayered tissue was hyperechoic (mean thickness 0.9 ± 0.3 mm) on ultrasound imaging. The roof of the cubital tunnel is elastic, formed by a myofascial trilaminar retinaculum. The pathological fusion of these three layers reduces gliding of the ulnar nerve during movements of the elbow joint. This may play a role in producing the symptoms typical of cubital tunnel syndrome. Independent from the surgical technique, decompression should span the ulnar nerve from the triceps brachii muscle to the flexor carpi ulnaris fascia. © 2014 Anatomical Society.

  17. Mathematical interpretation of monitoring results of the rock mass and TBM interaction

    Directory of Open Access Journals (Sweden)

    Víťazoslav Krúpa


    Full Text Available The monitoring of input and uotput parameters of excavation process using the full-face tunnelling machine provides the determination of properties of excavated rock mass. A mathematical apparatus was designed to solve the task by the description of the interaction between disc cutters and rock mass at the contact surface. The mathematical models were verified by a comparison with the results of the detailed engineering-geological investigation realized in an exploratory gallery of the Branisko highway tunnel in sections excavated by the full-face tunnelling machine Wirth TB-II-330H.

  18. Gun-lock and fire-lighter flints from excavations in Kazan: experimental use-wear research

    Directory of Open Access Journals (Sweden)

    Galimova Madina Sh.


    Full Text Available The results of experimental and use-wear research in assemblage of the flint artifacts from the 1995-2005 excavations in Kazan are represented in the article. The study has been motivated by the necessity to identify the finds of flint items either as prehistoric scrapers, blades, and cores or as gun-lock and fire-starter flints. In order to define the items’ use-wear features, a set of standard pattern tools (gun and fire flints has been produced and used. Experimental shooting has been carried out using a replica of a 1806 Russian musket. An iron fire-lighter dating to the 15th-17th centuries (an occasional find has been applied in experimental fire-making by striking sparks using the standard pattern flints. The microscopic analysis of the standard pattern gun and fire flints made it possible for the authors to identify the macro- and micro-wear traces. The traceological analysis of the flint artifacts (54 samples has revealed the wear peculiarities of the gun-flints and fire stones. As a result, most flint scrapers and retouched blades found in Kazan have been identified as gun-flints whereas the cores and massive flakes have been attributed as fire stones. Only five fire flints bear the remaining traces of real scraper working parts on their striking edges. The extreme degree of utilization of the gun-flints made of qualitative raw material and reutilization of prehistoric scrapers and cores is supposed to be caused by a shortage of qualitative flint with the population of Kazan in the 17th and 18th centuries.

  19. Analysis of 19th century ceramic fragments excavated from Pirenópolis (Goiás, Brazil) using FT-IR, Raman, XRF and SEM. (United States)

    Freitas, Renato P; Coelho, Filipe A; Felix, Valter S; Pereira, Marcelo O; de Souza, Marcos André Torres; Anjos, Marcelino J


    This study used Raman, FT-IR and XRF spectroscopy and SEM to analyze ceramic fragments dating from the 19th century, excavated from an old farm in the municipality of Pirenópolis, Goiás, Brazil. The results show that the samples were produced in an open oven at a firing temperature below 500°C, using raw materials including kaolinite, hematite, magnetite, quartz, microcline, albite, anhydrite, calcite, illite, orthoclase and MnO 2 . Although the analyses showed similarities in the manufacturing process and the presence of many minerals was common in all samples, multivariate statistical methods (PCA) allowed a more detailed assessment of similarities and differences in the mineral composition of the samples. The results of the PCA showed that the samples excavated in one of the slave quarters (senzalas) group with those excavated at the farmhouse, where the landowner lived, which indicates a paternalistic attitude towards captives, including the sharing of ceramic materials of everyday use. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. A comparative microbiological study to assess caries excavation by conventional rotary method and a chemo-mechanical method

    Directory of Open Access Journals (Sweden)

    Rajesh T Anegundi


    Full Text Available Aims: This study was aimed to determine the effectiveness of Papacαrie® for caries removal as compared to the conventional method with respect to microbial flora, time, the amount of tissue removal, child′s behavior, pain perception, and preference of treatment. Materials and Methods: Sixty primary molars of 30 children of age 4-9 years were selected randomly and divided into two groups of 30 teeth each: Group A treated by conventional method and group B with Papacαrie® method. Results: Comparatively, no statistical difference was seen in microbial growth, total bacterial count, and lactobacilli count in both the groups ( P = 0.36. The mean cavity entrance size with group A was 0.98133 mm and group B was 0.26083 mm ( P < 0.001. The mean preparation time for group A was 4.7 Mins (minutes and group B was 17.96 min s ( P < 0.001. Majority of kids of both group A and B scored 3 (Frankl Behavior Rating Scale before and after the treatment showing no statistical difference in their behavioral score ( P = 1. In group A 50% of children experienced no pain as compared to 86.7% in group B ( P = 0.01. There was no statistical difference in the preference of treatment ( P = 0.12. Conclusion: Thus, the Chemo mechanical caries removal method can be considered as an effective method to control pain and preserve sound tooth structure during caries excavation.

  1. Excavation Induced Hydraulic Response of Opalinus Clay - Investigations of the FE-Experiment at the Mont Terri URL in Switzerland (United States)

    Vogt, T.; Müller, H. R.; Garitte, B.; Sakaki, T.; Vietor, T.


    The Full-Scale Emplacement (FE) Experiment at the Mont Terri underground research laboratory in Switzerland is a full-scale heater test in a clay-rich formation (Opalinus Clay). Based on the Swiss disposal concept it simulates the construction, emplacement, backfilling, and post-closure thermo-hydro-mechanical (THM) evolution of a spent fuel / vitrified high-level waste (SF / HLW) repository tunnel in a realistic manner. The main aim of this experiment is to investigate SF / HLW repository-induced THM coupled effects mainly in the host rock but also in the engineered barrier system (EBS), which consists of bentonite pellets and blocks. A further aim is to gather experience with full-scale tunnel construction and associated hydro-mechanical (HM) processes in the host rock. The entire experiment implementation (in a 50 m long gallery with approx. 3 m diameter) as well as the post-closure THM evolution will be monitored using a network of several hundred sensors (state-of-the-art sensors and measurement systems as well as fiber-optic sensors). The sensors are distributed in the host rock's near- and far-field, the tunnel lining, the EBS, and on the heaters. The heater emplacement and backfilling has not started yet, therefore only the host rock instrumentation is installed at the moment and is currently generating data. We will present the instrumentation concept and rationale as well as the first monitoring results of the excavation and ventilation phase. In particular, we investigated the excavation induced hydraulic response of the host rock. Therefore, the spatiotemporal evolution of porewater-pressure time series was analyzed to get a better understanding of HM coupled processes during and after the excavation phase as well as the impact of anisotropic geomechanic and hydraulic properties of the clay-rich formation on its hydraulic behavior. Excavation related investigations were completed by means of inclinometer data to characterize the non-elastic and time

  2. Heybridge: A late Iron Age and Roman settlement. Excavations at Elms Farm 1993-5. Volume 2

    Directory of Open Access Journals (Sweden)

    Mark Atkinson


    Full Text Available The Late Iron Age, Roman and early Saxon settlement at Elms Farm, Heybridge, Essex was excavated in the mid-1990s, in advance of the construction of a large housing estate by Bovis Homes Ltd. The total development area comprised c. 29 hectares, of which some 18ha were subject to varying degrees of investigation by the Essex County Council Field Archaeology Unit (ECC FAU. The large-scale of the excavations is matched by the substantial and important artefact assemblage recovered, which included 6.4 tonnes of Late Iron Age and Roman pottery, 2,910 Roman coins and over 9000 animal bones. Together this has enabled an appreciation of the development of the settlement over time and space, of the changing functions, status and economy of individual areas and the settlement as a whole, and the issues of transition, change and finally decline. The site revealed evidence for activity from the Bronze Age to the post-medieval period. The evidence for the earliest settlement dates to the Late Iron Age period (mid 1st century BC and is rather fragmentary in nature. However a centrally located shrine, with a series of strip-plots to the north and south were tentatively identified. This settlement was remodelled around the mid 1st century AD, with the creation of a formal infrastructure of metalled roads, as well as a new temple precinct on the earlier sacred site and a reworking of the strip-plots into enclosures. This remodelling spanned the Late Iron Age/early Roman transition period, although the new road network is tentatively dated to the decade or two preceding the Roman conquest. To the north of the settlement area were a number of burials, pyre sites and pyre debris dumps. Early Roman cremations were added to this area slightly later. Some of the pyre sites exhibit higher-status elements, and at least one may have been 'aristocratic', suggesting the presence of a local elite. Reconstruction of settlement at Heybridge by Roger Massey-Ryan The later 1st

  3. Tunneling times in bianisotropic, dispersive and absorptive metamaterials (United States)

    Radosavljević, Sanja; Radovanović, Jelena; Milanović, Vitomir


    Tunneling times in complex bianisotropic materials have been examined in detail, with absorption and dispersion taken into account. Tunneling is characterized by the dwell and the phase tunneling time. In this paper, we have developed a theoretical model and derived the appropriate expressions for each of these quantities, as well as a relationship between them and the corresponding expression for the energy density. The model has been verified through numerical calculations based on experimental data. We have distinguished cases in which the phases of transmitted and incident wave match each other, and showed that for small angles of incidence, the time that the wave spends inside the barrier can be approximated as a linear function of the barrier width. The Hartman effect has been detected, although for very thick layers of metamaterial.

  4. Coexistence of tunneling magnetoresistance and Josephson effects in SFIFS junctions

    Directory of Open Access Journals (Sweden)

    O. Vávra


    Full Text Available We demonstrate an integration of tunneling magnetoresistance and the Josephson effects within one tunneling junction. Several sets of Nb-Fe-Al-Al2O3-Fe-Nb wafers with varying Al and Fe layers thickness were prepared to systematically explore the competition of TMR and Josephson effects. A coexistence of the critical current IC(dFe and the tunneling magnetoresistance ratio T M R(dFe is observed for iron layer dFe thickness range 1.9 and 2.9 nm. Further optimization such as thinner Al2O3 layer leads to an enhancement of the critical current and thus to an extension of the coexistence regime up to dFe≃3.9 nm Fe.

  5. Experimental study of drag reduction in flumes and spillway tunnels

    Directory of Open Access Journals (Sweden)

    Ying-kui Wang


    Full Text Available Experiments in an open flume model and spillway tunnel model were carried out using drag reduction techniques. Two drag reduction techniques were adopted in the experiments: polymer addition and coating. The drag reduction effect of a polyacrylamide (PAM solution and dimethyl silicone oil coating were studied in the flume model experiments, and the results were analyzed. Experiments were then carried out with a model of the Xiluodu Hydropower Station, the second largest dam in China. In order to reduce the resistance, the spillway tunnels were internally coated with dimethyl silicone oil. This is the first time that these drag reduction techniques have been applied to so large a hydraulic model. The experimental results show that the coating technique can effectively increase flood discharge. The outlet velocity and the jet trajectory distance are also increased, which enhances the energy dissipation of the spillway tunnel.

  6. Aerofoil flutter: fluid-mechanical analysis and wind tunnel testing (United States)

    Wensuslaus, A. L.; McMillan, A. J.


    This paper describes a three dimensional wing model, which has been developed for the purpose of studying flutter, both computationally and through wind tunnel testing. A three dimensional, laminar flow aerofoil wing, based on the NACA aerofoil has been designed. The natural frequencies for this aerofoil were obtained through modal analysis. A scale model wing, without taper was manufactured in the laboratory and tested in a wind tunnel. The pressure data was obtained from fluid flow analysis and the deformation results obtained through structural analysis. The analysis was performed in the ANSYS Workbench Environment, accessing FLUENT CFX for the computational fluid dynamics analysis and the ANSYS FEA package for the mechanical analysis. The computational results obtained are compared with the experimental data obtained in the wind tunnel. Comparison of the analysis and test results provides further understanding of the flutter characteristics.

  7. SMART Rotor Development and Wind-Tunnel Test (United States)

    Lau, Benton H.; Straub, Friedrich; Anand, V. R.; Birchette, Terry


    Boeing and a team from Air Force, NASA, Army, Massachusetts Institute of Technology, University of California at Los Angeles, and University of Maryland have successfully completed a wind-tunnel test of the smart material actuated rotor technology (SMART) rotor in the 40- by 80-foot wind-tunnel of the National Full-Scale Aerodynamic Complex at NASA Ames Research Center, figure 1. The SMART rotor is a full-scale, five-bladed bearingless MD 900 helicopter rotor modified with a piezoelectric-actuated trailing-edge flap on each blade. The development effort included design, fabrication, and component testing of the rotor blades, the trailing-edge flaps, the piezoelectric actuators, the switching power amplifiers, the actuator control system, and the data/power system. Development of the smart rotor culminated in a whirl-tower hover test which demonstrated the functionality, robustness, and required authority of the active flap system. The eleven-week wind tunnel test program evaluated the forward flight characteristics of the active-flap rotor, gathered data to validate state-of-the-art codes for rotor noise analysis, and quantified the effects of open- and closed-loop active-flap control on rotor loads, noise, and performance. The test demonstrated on-blade smart material control of flaps on a full-scale rotor for the first time in a wind tunnel. The effectiveness and the reliability of the flap actuation system were successfully demonstrated in more than 60 hours of wind-tunnel testing. The data acquired and lessons learned will be instrumental in maturing this technology and transitioning it into production. The development effort, test hardware, wind-tunnel test program, and test results will be presented in the full paper.

  8. Carpal and cubital tunnel and other, rarer nerve compression syndromes. (United States)

    Assmus, Hans; Antoniadis, Gregor; Bischoff, Christian


    Carpal tunnel syndrome is by far the most common peripheral nerve compression syndrome, affecting approximately one in every six adults to a greater or lesser extent. Splitting the flexor retinaculum to treat carpal tunnel syndrome is the second most common specialized surgical procedure in Germany. Cubital tunnel syndrome is rarer by a factor of 13, and the other compression syndromes are rarer still. This review is based on publications retrieved by a selective literature search of PubMed and the Cochrane Library, along with current guidelines and the authors' clinical and scientific experience. Randomized controlled trials have shown, with a high level of evidence, that the surgical treatment of carpal tunnel syndrome yields very good results regardless of the particular technique used, as long as the diagnosis and the indication for surgery are well established by the electrophysiologic and radiological findings and the operation is properly performed. The success rates of open surgery, and the single-portal and dual-portal endoscopic methods are 91.6%, 93.4% and 92.5%, respectively. When performed by experienced hands, all these procedures have complication rates below 1%. The surgical treatment of cubital tunnel syndrome has a comparably low complication rate, but worse results overall. Neuro-ultrasonography and magnetic resonance imaging (neuro-MRI) are increasingly being used to complement the diagnostic findings of electrophysiologic studies. Evidence-based diagnostic methods and treatment recommendations are now available for the two most common peripheral nerve compression syndromes. Further controlled trials are needed for most of the rarer syndromes, especially the controversial ones.

  9. Excavation of hard deposits and rocks : On the cutting of saturated rock

    NARCIS (Netherlands)

    Helmons, R.L.J.


    As a result of the worldwide population and welfare growth, the demand for energy (oil, gas and renewable sources) and raw materials increases. In the last decades, oil and gas are produced from more and more offshore sites and deeper waters. Besides energy, the demand for diverse metals and rare

  10. Characteristics and environmental fate of the anionic surfactant sodium lauryl ether sulphate (SLES) used as the main component in foaming agents for mechanized tunnelling. (United States)

    Barra Caracciolo, Anna; Cardoni, Martina; Pescatore, Tanita; Patrolecco, Luisa


    The anionic surfactant sodium lauryl ether sulphate (SLES) is the main component of most commercial products used for soil conditioning in the excavation industry, in particular as lubricants for mechanized tunnelling. Its use during the excavation processes can result in either the subsequent possible re-use of the huge amount of soil debris as by-products (e.g. land covering) or its discharge as waste. Currently, there are neither SLES soil threshold limits in European legislation, nor comprehensive studies on the environmental risk for soil ecosystems in these exposure scenarios. In this context, the present paper reviews the available data on the intrinsic characteristics of persistence and the ecotoxicological effects of the anionic surfactant SLES. Although SLES is generally reported to be biodegradable in standard tests, with degradation rates between 7 h and 30 days, depending on the initial conditions, data on its biodegradation in environmental studies are quite scarce. Consequently, assessing SLES biodegradation rates in field conditions is crucial for evaluating if in residual concentrations (typically in the range 40-500 mg/kg in excavated soils) it can or not be a potential hazard for terrestrial and water organisms. Laboratory ecotoxicological tests pointed out detrimental effects of SLES for aquatic organisms, while data on the terrestrial species are rather poor so far and further studies at the expected environmental concentrations are necessary. Finally, the review reports the main analytical methods available for detecting anionic surfactants in solid matrices and the future research needed to improve knowledge on the possible environmental risks posed by the use of SLES in foaming agents for mechanized tunnelling. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Double-Barrier Resonant Tunneling in Three and Two Dimensions (United States)

    Zaslavsky, Alexander

    Double-barrier resonant tunneling devices have attracted great scientific interest, both as novel physical systems based on strong size quantization that exhibit unusual transport behavior and also as a promising class of semiconductor structures for high-speed electronic devices. This thesis describes the physics of transport in double-barrier structures fabricated by conventional planar growth, where the fundamental process involves tunneling from three-dimensional (3D) into two-dimensional (2D) densities of electronic states, as well as in novel 2D double-barrier structures fabricated by regrowth, where 2D electrons tunnel into well-separated ID quantum wire subbands. A brief introduction to the basic theory of resonant tunneling and the results of low-temperature I(V) transport measurements on high -quality planar double-barrier devices is presented in Chapter 1. Chapter 2 examines the bistable I(V) characteristic observed in specially designed asymmetric devices, with the intrinsic nature of this effect confirmed by parallel field magnetotunneling measurements. In Chapter 3 transverse field magnetotunneling is employed to experimentally verify the energy and transverse momentum selection rules that govern transport in resonant tunneling devices. Chapter 4 focuses on the fabrication of 2D resonant tunneling devices by liquid phase epitaxial regrowth on patterned substrates. A brief overview of liquid phase epitaxy and two different in-situ patterning techniques--selective meltback and cleaving inside the chamber--are presented. The measurements of the 2D device fabricated by regrowth on cleaved substrates are presented and analyzed in Chapter 5. The new possibilities opened up by the cleaved substrate regrowth techniques are also discussed, including the realization of an edge -regrown superlattice with novel high-field transport characteristics.

  12. Seismic scanning tunneling macroscope - Elastic simulations and Arizona mine test

    KAUST Repository

    Hanafy, Sherif M.


    Elastic seismic simulations and field data tests are used to validate the theory of a seismic scanning tunneling macroscope (SSTM). For nearfield elastic simulation, the SSTM results show superresolution to be better than λ/8 if the only scattered data are used as input data. If the direct P and S waves are muted then the resolution of the scatterer locations are within about λ/5. Seismic data collected in an Arizona tunnel showed a superresolution limit of at least λ/19. These test results are consistent with the theory of the SSTM and suggest that the SSTM can be a tool used by geophysicists as a probe for near-field scatterers.

  13. Does the availability of artificial cavities affect cavity excavation rates in red-cockaded woodpeckers? (United States)

    Richard N. Conner; Daniel Saenz; D. Craig Rudolph; Richard R. Schaefer


    Rates of cavity excavation by Red-cockaded Woodpeckers (Picoides borealis) were examined from 1983 to 1999 on the Angelina National Forest in east Texas. We compared the rare of natural cavity excavation between 1983 and 1990 (before artificial cavities were available) with the rate of cavity excavation between 1992 and 1993, a period when...

  14. 18 CFR 1304.207 - Channel excavation on TVA-owned residential access shoreland. (United States)


    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Channel excavation on... OF STRUCTURES AND OTHER ALTERATIONS TVA-Owned Residential Access Shoreland § 1304.207 Channel excavation on TVA-owned residential access shoreland. (a) Excavation of individual boat channels shall be...

  15. Description, reliability and validity of a novel method to measure carpal tunnel pressure in patients with carpal tunnel syndrome. (United States)

    Coppieters, Michel W; Schmid, Annina B; Kubler, Paul A; Hodges, Paul W


    Elevated carpal tunnel pressure is an important pathomechanism in carpal tunnel syndrome (CTS). Several invasive methods have been described for direct measurement of carpal tunnel pressure, but all have two important limitations. The pressure gauge requires sterilisation between uses, which makes time-efficient data collection logistically cumbersome, and more importantly, the reliability of carpal tunnel pressure measurements has not been evaluated for any of the methods in use. This technical note describes a new method to measure carpal tunnel pressure using inexpensive, disposable pressure sensors and reports the within and between session reliability of the pressure recordings in five different wrist positions and during typing and computer mouse operation. Intraclass correlation coefficients (ICC[3,1]) were calculated for recordings within one session for healthy participants (n = 7) and patients with CTS (n = 5), and for recordings between two sessions for patients with CTS (n = 5). Overall, the reliability was high. With the exception of two coefficients, the reliability of the recordings at different wrist angles varied from 0.63 to 0.99. Reliability for typing and mouse operation ranged from 0.86 to 0.99. The new method described in this report is inexpensive and reliable, and data collection can be applied more efficiently as off-site sterilisation of equipment is not required. These advances are likely to promote future research into carpal tunnel pressure, such as investigation of the therapeutic mechanisms of various conservative treatment modalities that are believed to reduce elevated carpal tunnel pressure. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Burial, excavation, and preparation of primate skeletal material for morphological study. (United States)

    Garrod, Ben; Roberts, Alice M; Duhig, Corinne; Cox, Debby; McGrew, William


    Inclusion of osteological material in primatological research has a long history, and use of skeletal remains continues to be important in anatomical and anthropological research. Here we report a set of proven methods, including equipment, protocol, and procedure, which enable relatively simple acquisition of skeletal material from naturally deceased animals in field sites and sanctuaries. Such skeletal material, often with extensive accompanying life-history data, is a unique and valuable source of data for both academic and conservation-based research.

  17. Characterization of Underwater Sounds Produced by a Backhoe Dredge Excavating Rock and Gravel (United States)


    Oncorhynchus tshawytscha) and northern anchovy (Engraulis mordax) exposed to pile-driving sounds and observed no differences in behaviors of treatment 1 µPA at 1,500 m. Peak spectral level was 131 dB at 1,500 m at a peak frequency of 350 Hz. The Center for Environment, Fisheries, and Aquaculture

  18. Elemental analyses on porcelains of Tang and Song Dynasties excavated from Yongjinwan zone at Jinsha site (United States)

    Xia, C. D.; Ge, L. J.; Liu, M. T.; Zhu, J. J.; An, Z.; Bai, B.


    The work presented here carried out elemental analyses on 60 porcelain shards of Tang and Song Dynasties, unearthed from Yongjinwan zone at Jinsha site, Sichuan, China, using a combination of PIXE and RBS methods. Six shards from Liulichang kiln site and 6 from Shifangtang kiln site were also analyzed as reference materials. The factor analyses for the elemental compositions in the bodies and glazes of the total 72 porcelain shards have been performed to explore their similarities and differences. Combining the results of factor analyses on elements in bodies and glazes and the classification by traditional archaeological criteria, the provenances for most of shards unearthed from Yongjinwan zone in Jinsha site could be determined. Majority of shards with a Qiong-kiln style were found as products of Liulichang kiln, this is consistent with Yongjinwan's geographical location and social environment, i.e., Yongjinwan was a suburban settlement nearest to Liulichang kiln in ancient times. Although both products of Liulichang kiln and Shifangtang kiln belonged to Qiong-kiln system and they shared a similar appearance such as red body and celadon glaze, there were distinct differences in chemical composition which could be unraveled by PIXE-RBS measurements and factor analysis. There were no apparent differences of chemical compositions for the same kinds of body and glaze between Tang and Song Dynasties, which may suggest that raw materials and production techniques for the same kinds of body and glaze continued between Tang and Song Dynasties. The chemical characteristics for each kind of body and glaze and the correlations between element composition and porcelain appearance were also obtained in this work.

  19. Surgical Demographics of Carpal Tunnel Syndrome and Cubital Tunnel Syndrome Over 5 Years at a Single Institution. (United States)

    Zhang, Dafang; Collins, Jamie E; Earp, Brandon E; Blazar, Philip


    Carpal tunnel and cubital tunnel syndrome are the 2 most common upper-limb compressive neuropathies. However, whether the characteristics of patient populations undergoing surgery for these conditions are similar is unclear in terms of demographics and concomitant pathologies. Our null hypothesis was that there are no identifiable differences between these patient populations. A retrospective cohort study was performed by billing system query using Common Procedural Terminology (CPT) codes for all patients who underwent open carpal tunnel release (CTR) (CPT code 64721) and/or open cubital tunnel surgery (CPT code 64718) by 1 of 4 hand surgeons from August 2008 to July 2013. Application of exclusion criteria of acute trauma, revision surgery, neoplasm, age less than 18 years, and inaccurate or insufficient records resulted in identification of 1,114 patients who underwent CTR, 264 patients who underwent cubital tunnel surgery, and 76 patients who underwent both. Computerized medical records were analyzed for demographic variables, medical comorbidities, and other procedures performed under the same anesthetic. In the multivariable analysis, older age, female sex, higher body mass index, trigger finger, and de Quervain tenosynovitis were associated with CTR. Prior trauma to the anatomic site was more common in the cubital tunnel group. Diabetes mellitus was associated with patients who had both procedures. The populations of patients who undergo surgery for different upper-extremity compressive neuropathies are not homogenous: CTR is associated with older age, female sex, higher body mass index, and hand tendinopathies. Cubital tunnel decompression is associated with prior trauma to the anatomic site. Diabetic patients are more likely to have both procedures. Diabetic patients undergoing either procedure should be evaluated for other peripheral nerve compression pathologies. Diagnostic IV. Copyright © 2017 American Society for Surgery of the Hand. Published by

  20. Internship Tasks Associated With CIF Icy Regolith Excavation and Volatile Capture Under Vacuum Conditions (United States)

    Ballesteros, Erik Nicholas


    Understanding the surface and atmosphere of Mars is critical to current and future development of exploration systems. Dealing with the Martian regolith-the top layer of soil-remains a significant challenge, and much research is still needed. Addressing this need, the Cryogenics Test Lab and Granular Mechanics and Regolith Operations Lab at NASA's Kennedy Space Center are partnering to develop an apparatus that utilizes simulated Martian regolith in an analogous atmospheric environment to gather data about how the material behaves when exposed to water vapor. Martian surface temperatures range from 128 K (-145 C) to 308 K (35 C), and the average pressure is approximately 4.5 Torr; which presents an environment where water can potentially exist in vapor, solid or liquid form. And based on prior Mars missions such as the Phoenix Lander, it is known that water-ice exists just below the surface. This test apparatus will attempt to recreate the conditions that contributed to the Martian ice deposits by exposing a sample to water vapor at low pressure and temperature; thereby forming ice inside the simulant via diffusion. From this, we can better understand the properties and behavior of the regolith, and have more knowledge concerning its ability to store water-and subsequently, how to dig up and extract that water-which will be crucial to sample gathering when the first manned Mars mission takes place.

  1. [Nondestructive analysis of the silicate artifacts excavated from Baofeng and Xinzheng, Henan Province]. (United States)

    Fu, Qiang; Zhao, Hong-Xia; Dong, Jun-Qing; Li, Qing-Hui; Hu, Yong-Qing


    Nondestructive analysis plays an important role in the studies of ancient artifacts. The present paper reports the chemical compositions and micro-area phases of 21 silicate artifacts samples analyzed by portable X-ray fluorescence spectrometer and laser Raman spectrometer. Based on the chemical compositions, these samples can be divided into PbO-BaO-SiO2, K2O-SiO2 glass systems, faience and PbO-BaO glassy faience which were discussed respectively, and preliminary investigation of colorants in different parts of some samples was also involved. By laser Raman spectroscopy, Chinese blue (BaCuSi4O10), Chinese purple (BaCuSi2O6) and Chinese dark blue (BaCu2Si2O7) were identified invasively in the blue pigment of some eye beads and circle beads, and then a variety of mineral phase including quartz, calcite, lead carbonate, burnt umber and terre verte were also analyzed successfully in the same way. According to the archaeological research results, the provenances of these samples were discussed briefly. PbO-BaO-SiO2 glass, K2O-SiO2 ear pendant and PbO-BaO glassy faience were made in China while the faience was suspected to be from the west. Those results illustrated the communications of culture and technologies among different regions of ancient China, and between ancient China and the western regions. The combination of portable X-ray fluorescence spectrometer and laser Raman spectrometer can provide chemical and phase information of relics, and has great advantages in scientific analysis of ancient artifacts, which supports future studies of archaeology.

  2. A further excavation of seduction, seduction trauma, and the seduction theory. (United States)

    Blum, Harold P


    Freud's pre-analytic concept of seduction trauma was interwoven with the emerging concepts of an unconscious pathogenic past, repression, and reconstruction. The formulation of this theory of neurosogenesis involved important current, as well as past, determinants. Freud was psychologically seduced by Fliess and unwittingly colluded in the nearly fatal surgery Fliess performed on Emma Eckstein. The formulation and subsequent repudiation of the seduction theory approximated the period from the traumatic experience of Freud with his patient Emma Eckstein to her apparent recovery. Freud's seduction theory, with its focus on childhood sexual abuse, simultaneously defended against both aggression and the current traumatic situation. Defenses against aggression were intensified in an atmosphere of virulent anti-Semitism. The seduction theory is relevant to contemporary issues concerning psychic trauma, psychic reality and objective reality, memory, and reconstruction.

  3. Quantification of Plume-Soil Interaction and Excavation Due to the Sky Crane Descent Stage (United States)

    Vizcaino, Jeffrey; Mehta, Manish


    The quantification of the particulate erosion that occurs as a result of a rocket exhaust plume impinging on soil during extraterrestrial landings is critical for future robotic and human lander mission design. The aerodynamic environment that results from the reflected plumes results in dust lifting, site alteration and saltation, all of which create a potentially erosive and contaminant heavy environment for the lander vehicle and any surrounding structures. The Mars Science Lab (MSL), weighing nearly one metric ton, required higher levels of thrust from its retro propulsive systems and an entirely new descent system to minimize these effects. In this work we seek to quantify plume soil interaction and its resultant soil erosion caused by the MSL's Sky Crane descent stage engines by performing three dimensional digital terrain and elevation mapping of the Curiosity rover's landing site. Analysis of plume soil interaction altitude and time was performed by detailed examination of the Mars Descent Imager (MARDI) still frames and reconstructed inertial measurement unit (IMU) sensor data. Results show initial plume soil interaction from the Sky Crane's eight engines began at ground elevations greater than 60 meters and more than 25 seconds before the rovers' touchdown event. During this time, viscous shear erosion (VSE) was dominant typically resulting in dusting of the surface with flow propagating nearly parallel to the surface. As the vehicle descended and decreased to four powered engines plume-plume and plume soil interaction increased the overall erosion rate at the surface. Visibility was greatly reduced at a height of roughly 20 meters above the surface and fell to zero ground visibility shortly after. The deployment phase of the Sky Crane descent stage hovering at nearly six meters above the surface showed the greatest amount of erosion with several large particles of soil being kicked up, recirculated, and impacting the bottom of the rover chassis. Image

  4. Evolutionary anthropology and genes: investigating the genetics of human evolution from excavated skeletal remains. (United States)

    Anastasiou, Evilena; Mitchell, Piers D


    The development of molecular tools for the extraction, analysis and interpretation of DNA from the remains of ancient organisms (paleogenetics) has revolutionised a range of disciplines as diverse as the fields of human evolution, bioarchaeology, epidemiology, microbiology, taxonomy and population genetics. The paper draws attention to some of the challenges associated with the extraction and interpretation of ancient DNA from archaeological material, and then reviews the influence of paleogenetics on the field of human evolution. It discusses the main contributions of molecular studies to reconstructing the evolutionary and phylogenetic relationships between extinct hominins (human ancestors) and anatomically modern humans. It also explores the evidence for evolutionary changes in the genetic structure of anatomically modern humans in recent millennia. This breadth of research has led to discoveries that would never have been possible using traditional approaches to human evolution. Copyright © 2013 Elsevier B.V. All rights reserved.



    Abdel-Kareem, Omar; Al-Zahrani, Awad; Al-Sadoun, Aljouhara


    The present work aims to develop and establish conservation processes for cleaning marine archaeological silver coins - the Shoiba Hoard Coins in Red Sea, Shoiba Port, near Jeddah, Saudi Arabia. To help the archaeologists study and date these coins, it was necessary to reveal the impeded decorations and the inscriptions on these coins. Before establishing the experimental work to evaluate the selected conservation processes, various tests were performed on different types of the selected coin...

  6. Archeological Investigations in Cochiti Reservoir, New Mexico. Volume 2. Excavation and Analysis 1975 Season. (United States)


    large mammal. Two were rib fragments and the other was a complete in- 13 Achenes These were of a type which resembled cisor. Bahia , but there axe so...predominate the assemblages. Together the obsidian andof immigrant potters unfamiliar with the traditions of chalcedony lithics make up between 65% and 70% of

  7. Excavating Neandertal and Denisovan DNA from the genomes of Melanesian individuals. (United States)

    Vernot, Benjamin; Tucci, Serena; Kelso, Janet; Schraiber, Joshua G; Wolf, Aaron B; Gittelman, Rachel M; Dannemann, Michael; Grote, Steffi; McCoy, Rajiv C; Norton, Heather; Scheinfeldt, Laura B; Merriwether, David A; Koki, George; Friedlaender, Jonathan S; Wakefield, Jon; Pääbo, Svante; Akey, Joshua M


    Although Neandertal sequences that persist in the genomes of modern humans have been identified in Eurasians, comparable studies in people whose ancestors hybridized with both Neandertals and Denisovans are lacking. We developed an approach to identify DNA inherited from multiple archaic hominin ancestors and applied it to whole-genome sequences from 1523 geographically diverse individuals, including 35 previously unknown Island Melanesian genomes. In aggregate, we recovered 1.34 gigabases and 303 megabases of the Neandertal and Denisovan genome, respectively. We use these maps of archaic sequences to show that Neandertal admixture occurred multiple times in different non-African populations, characterize genomic regions that are significantly depleted of archaic sequences, and identify signatures of adaptive introgression. Copyright © 2016, American Association for the Advancement of Science.

  8. Detecting and monitoring of water inrush in tunnels and coal mines using direct current resistivity method: A review

    Directory of Open Access Journals (Sweden)

    Shucai Li


    Full Text Available Detecting, real-time monitoring and early warning of underground water-bearing structures are critically important issues in prevention and mitigation of water inrush hazards in underground engineering. Direct current (DC resistivity method is a widely used method for routine detection, advanced detection and real-time monitoring of water-bearing structures, due to its high sensitivity to groundwater. In this study, the DC resistivity method applied to underground engineering is reviewed and discussed, including the observation mode, multiple inversions, and real-time monitoring. It is shown that a priori information constrained inversion is desirable to reduce the non-uniqueness of inversion, with which the accuracy of detection can be significantly improved. The focused resistivity method is prospective for advanced detection; with this method, the flanking interference can be reduced and the detection distance is increased subsequently. The time-lapse resistivity inversion method is suitable for the regions with continuous conductivity changes, and it can be used to monitor water inrush in those regions. Based on above-mentioned features of various methods in terms of benefits and limitations, we propose a three-dimensional (3D induced polarization method characterized with multi-electrode array, and introduce it into tunnels and mines combining with real-time monitoring with time-lapse inversion and cross-hole resistivity method. At last, the prospective applications of DC resistivity method are discussed as follows: (1 available advanced detection technology and instrument in tunnel excavated by tunnel boring machine (TBM, (2 high-resolution detection method in holes, (3 four-dimensional (4D monitoring technology for water inrush sources, and (4 estimation of water volume in water-bearing structures.

  9. Foundation, excavation and radiation shielding concepts for a 16-m large lunar telescope (United States)

    Chua, Koon M.; Johnson, Stewart W.


    NASA is considering a 16-m diameter optical telescope on the moon as a part of the Space Exploration Initiative. Fundamental concepts of engineering activities on the moon and how they can be applied to the establishment of a 16-m large lunar telescope (LLT) are discussed. These fundamental concepts include the engineering response of lunar soils and how they affect construction activities, namely, drilling, blasting, ripping, digging and compaction. A mirror support structure and foundation design concept is proposed. The foundation considered is a multiple contact points spud-can type footing. It does not appear that a deep foundation or the presence of bedrock is required to achieve the telescope foundation stiffness. The LLT system will include a regolith covered housing, the size of a small room, which will contain sensitive electronic equipment including charge coupled devices which need protection from cosmic radiation effects. A brief discussion is made on radiation, radiation transport and radiation effects on electronics and on humans. Radiation protection techniques and the different emplacement schemes for the LLT instrument housing for radiation protection are suggested. A structural concept of an early lunar based telescope is also presented.

  10. Basin Excavation, Lower Crust, Composition, and Bulk Moon Mass balance in Light of a Thin Crust (United States)

    Jolliff, B. L.; Korotev, R. L.; Ziegler, R. A.


    New lunar gravity results from GRAIL have been interpreted to reflect an overall thin and low-density lunar crust. Accordingly, crustal thickness has been modeled as ranging from 0 to 60 km, with thinnest crust at the locations of Crisium and Moscoviense basins and thickest crust in the central farside highlands. The thin crust has cosmochemical significance, namely in terms of implications for the Moon s bulk composition, especially refractory lithophile elements that are strongly concentrated in the crust. Wieczorek et al. concluded that the bulk Moon need not be enriched compared to Earth in refractory lithophile elements such as Al. Less Al in the crust means less Al has been extracted from the mantle, permitting relatively low bulk lunar mantle Al contents and low pre- and post-crust-extraction values for the mantle (or the upper mantle if only the upper mantle underwent LMO melting). Simple mass-balance calculations using the method of [4] suggests that the same conclusion might hold for Th and the entire suite of refractory lithophile elements that are incompatible in olivine and pyroxene, including the KREEP elements, that are likewise concentrated in the crust.

  11. Foundation, excavation and radiation shielding concepts for a 16-m large lunar telescope (United States)

    Chua, Koon M.; Johnson, Stewart W.


    NASA is considering a 16-m diameter optical telescope on the moon as a part of the Space Exploration Initiative. Fundamental concepts of engineering activities on the moon and how they can be applied to the establishment of a 16-m large lunar telescope (LLT) are discussed. These fundamental concepts include the engineering response of lunar soils and how they affect construction activities, namely, drilling, blasting, ripping, digging and compaction. A mirror support structure and foundation design concept is proposed. The foundation considered is a multiple contact points spud-can type footing. It does not appear that a deep foundation or the presence of bedrock is required to achieve the telescope foundation stiffness. The LLT system will include a regolith covered housing, the size of a small room, which will contain sensitive electronic equipment including charge coupled devices which need protection from cosmic radiation effects. A brief discussion is made on radiation, radiation transport and radiation effects on electronics and on humans. Radiation protection techniques and the different emplacement schemes for the LLT instrument housing for radiation protection are suggested. A structural concept of an early lunar based telescope is also presented.

  12. 29 CFR 570.68 - Occupations in excavation operations (Order 17). (United States)


    ... 29 Labor 3 2010-07-01 2010-07-01 false Occupations in excavation operations (Order 17). 570.68...-Being § 570.68 Occupations in excavation operations (Order 17). (a) Finding and declaration of fact. The following occupations in excavation operations are particularly hazardous for the employment of persons...

  13. Restoration and Preservation of Engraved Limestone Blocks Discovered in Abu Mousa Excavation, Suez - Egypt

    Directory of Open Access Journals (Sweden)

    Nabil A. Abd El-Tawab BADER


    Full Text Available A lot of engraved limestone blocks were discovered at Awlad Abu Musa (east of Suez, Egypt in 1995/2007 by Supreme Council of Antiquities. The stone blocks were seriously affected by archaeological environments during burial environment in agriculture land. They were covered with thick clay layer with soil particles that disfigured them and hid their inscriptions. Prior to the conservation intervention, the materials were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy, Chemical analyses of ground water and microbiological study. After the material characterization, the conservation and restoration of the stone blocks were carried out including cleaning, consolidation, reduction of salts, Re-jointing, restoration and completion of lost parts. After that the blocks were exhibited in Suez museum.

  14. Mechanical and hydrological characterization of the near-field surrounding excavations in a geologic salt formation

    Energy Technology Data Exchange (ETDEWEB)

    Howard, Clifford L. [Sandia National Laboratories, Albuquerque, NM (United States)


    The technical basis for salt disposal of nuclear waste resides in salt’s favorable physical, mechanical and hydrological characteristics. Undisturbed salt formations are impermeable. Upon mining, the salt formation experiences damage in the near-field rock proximal to the mined opening and salt permeability increases dramatically. The volume of rock that has been altered by such damage is called the disturbed rock zone (DRZ).

  15. Review of The Earl of Abergavenny. Historical Record and Wreck Excavation CD-Rom

    Directory of Open Access Journals (Sweden)

    David Petts


    Full Text Available In early February 1805 a small fleet of East Indiamen accompanied by the frigate Weymouth set sail from Portsmouth heading first for Bengal and ultimately for China. However, barely had the voyage began when, following bad weather and confusion, one of the boats, the Earl of Abergavenny, struck the Shambles bank just off Portland Bill. Although the crew managed to free it, it was so badly damaged it sank while trying to make for the safety of Weymouth. Over 250 crew and passengers drowned. The wreck has until now been best known for causing the death of John Wordsworth, the ship's commander and brother of the poet William Wordsworth. This excellent CD report of archaeological investigations on the wreck site carried out since 1980 by the Weymouth Underwater Archaeological Group (WUAG brings us the full picture of the events leading up to the wreck, and a record of the remains found by the team of divers (Fig.1. The complex campaigns of diving have been carried out alongside extensive documentary and historical work. The huge amount of data created by this project has inevitably led to challenges for the WUAG regarding its publication (Cumming 2002. The decision to publish via a CD-ROM has allowed very large quantities of data and discussion to be published. The current version of the CD contains over 100,000 words of text, 1560 files and over 1000 illustrations (JPEGS. All for the grand price of 10 GBP. The volume can be browsed using a commercially available browser but is also supplied as compiled file using Web Compiler, which has the advantage of a search facility.

  16. Test Excavation and Evaluation of 45-FR-317, on the Middle Columbia River, Near Pasco, Washington. (United States)


    317. The relatively high number of cobble tools and the frequency of decortication flakes among the debitaqe suggest a local origin. Suitable cobbles...disarticulation of large mammal limbs (Flenniken 1976:93, 101). Five (41.7%) are primary decortication spalls, five (41.7%) are secondary decortication spalls...with cortex present on 121 items (72.9%). The type of cortex includes primary decortication (16.5%), covering a portion of the dorsal surface, and

  17. Archaeological Reconnaissance Survey and Salvage Excavation in the Salt Lick Recreation Area. (United States)


    region, all of the geological strata are nearly horizontal and-.dip gently away from the Nashville Dome! Central Basin area ( Floyd 1965:7-8, Figure also known that minor deposits of halite (rock salt) have been located in Anderson, White, Van Buren, Warren, Overton, and Jackson counties ( Floyd ...Banded Fossiliferous Pink Pink Cherty Limestone Quartzite Chalcedony 524’ Non-cryptocrystalline Clay (burnt) Sandstone Ferrous Sandstone Greenstone Shale

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

    Energy Technology Data Exchange (ETDEWEB)

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


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


    Directory of Open Access Journals (Sweden)



    Full Text Available On the account of the advantages benefited regarding the correlation of the sliding work regime with the specific characteristics of the predominant rocks from the lithostratigraphical structure of the Jiu Valley’s underground, the support of metallic elements continues to represent the most advantageous version from the technical and economical point of view. Besides a series of advantages, including the ensuring of bearing capacity expected per meter of work by applying the correct adopted support fields, the metallic support presents deficiencies generated by the irrational usage of steel for machining rolled profiles, with repercussions on imperfections recorded on element’s cold cutting and bending, including over the underground operation period of the armouring. The target of presented paper is to analyze those deficiencies with their evaluation trough analytical calculation and the presentation of counter measures

  20. Tunnelling through two successive barriers and the Hartman (superluminal) effect

    Energy Technology Data Exchange (ETDEWEB)

    Olkhovsky, V. [Institute for Nuclear Research, Kiev (Ukraine); Recami, E. [Istituto Nazionale di Fisica Nucleare, Milan (Italy)]|[Bergamo Univ., Bergamo (Italy). Fac. di Ingegneria]|[State Univ. of Campinas, Campinas (Brazil); Salesi, G. [Istituto Nazionale di Fisica Nucleare, Milan (Italy)]|[Bergamo Univ., Bergamo (Italy). Fac. di Ingegneria


    The paper studies the phenomenon of one-dimensional non-resonant tunnelling through two successive potential barriers, separated by an intermediate free region R, by analyzing the relevant solutions to the Schroedinger equation. The total traversal time does not depend not only on the barrier widths (the so called Hartman effect), but also on the R width: so the effective velocity in the region R, between the two barriers, can be regarded as infinite. This agrees with the results known from the corresponding waveguide experiments, which simulated the tunnelling experiment herein considered due to the formal identity between the Schroedinger and the Helmholtz equation.

  1. Excavating black hole continuum spectrum: Possible signatures of scalar hairs and of higher dimensions (United States)

    Banerjee, Indrani; Chakraborty, Sumanta; SenGupta, Soumitra


    Continuum spectrum from black hole accretion disc holds enormous information regarding the strong gravity regime around the black hole and hence about the nature of gravitational interaction in extreme situations. Since in such strong gravity regime the dynamics of gravity should be modified from the Einstein-Hilbert one, its effect should be imprinted on the continuum spectrum originating from the black hole accretion. To explore the effects of these alternative theories on the black hole continuum spectrum in an explicit manner, we have discussed three alternative gravitational models having their origin in three distinct paradigms—(a) higher dimensions, (b) higher curvature gravity, and (c) generalized Horndeski theories. All of them can have signatures sculptured on the black hole continuum spectrum, distinct from the standard general relativistic scenario. Interestingly all these models exhibit black hole solutions with tidal charge parameter which in these alternative gravity scenarios can become negative, in sharp contrast with the Reissner-Nordström black hole. Using the observational data of optical luminosity for eighty Palomer Green quasars we have illustrated that the difference between the theoretical estimates and the observational results gets minimized for negative values of the tidal charge parameter. As a quantitative estimate of this result we concentrate on several error estimators, including reduced χ2 , Nash-Sutcliffe efficiency, index of agreement etc. Remarkably, all of them indicates a negative value of the tidal charge parameter, signaling the possibility of higher dimensions as well as scalar charge at play in those high gravity regimes.

  2. Karstification Of Deep Karst In Maoba Syncline In Yuanliangshan Railway Tunnel, China: Field Investigation And Model Development (United States)

    Xu, M.; Mao, B.; Xiao, W.; Lu, G.; Jiang, L.


    Yuanliangshan tunnel is a critical feature of Chongqing-Huaihua railway transecting vast karst plateau in southwestern China. Tunnel excavation reveals three giant karst caves of filling-type in Maoba Syncline, consisting of P2w and P1m limestones. And these caves are located 400 meters below the local drainage base level. This finding contradicts conventional theory that only dissolved pores and corrosion fissures can develop in deep water-circulation zone. We conceptualize that at the center and eastern wing of Maoba syncline bedding detachment, longitudinal tension fractures and transverse tension fractures (NW-NWW) form the initial flow paths for the deep cycle of the karst aquifer. Inverse siphon cycle forms a slow, deep flow circulation. Conduits are formed by perennial erosion and dissolution. The giant caves form due to erosion and collapse of the ceilings. The caves are filled by clay, which deposits as a result of flow variations. Using the softwares Modflow and PHREEQC based on the borehole hydrochemical and hydrodynamic data, intensity of karstification in the Syncline was simulated. Results show that the intensity of P2w is stronger than P1m. The karstification at the center where karst developped is much more intense than that at the wings.

  3. Stormwater permitting for a large construction project: NPDES and Boston's Central Artery/Tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, B.B. (BSC Group, Boston, MA (United States))


    The promulgation of EPA's NPDES stormwater discharge regulations occurred during the latter planning stages for Boston's Central Artery/Tunnel Project, making this project, one of the largest single urban highway projects ever built, one of the first to be permitted under new regulations. The Project consists of 128 land miles of new highway, including numerous ramps and interchanges, and a harbor tunnel, with stormwater discharging during construction from at least 38 separate points. Complicating the permitting situation, stormwater is combined with dewatering discharges from excavations in filled and former industrial areas. Working closely with EPA Region 1 and the Massachusetts Department of Environmental Protection, the Massachusetts Highway Department submitted a permit application combining estimates of dewatering discharge quality derived from groundwater sampling with all the elements of a NPDES application for construction stormwater. The resulting permit contained two separate sets of monitoring requirements for the same discharge points, one for stormwater and one for dewatering. Quarterly monitoring was required for both dewatering and stormwater for metals, suspended solids, TPH, and VOC. Limits of 50 mg/1 TSS and 5 mg/1 TPH were established for dewatering only.

  4. Fiber Bragg Grating Sensors-Based In Situ Monitoring and Safety Assessment of Loess Tunnel

    National Research Council Canada - National Science Library

    Lai, Jinxing; Qiu, Junling; Fan, Haobo; Zhang, Qian; Hu, Zhinan; Wang, Junbao; Chen, Jianxun


    ... resistance, and good repeatability. In order to study the internal force of the tunnel liner and detect the potential safety hazards, series of strain monitoring tests of a loess tunnel, taking into account the complex stress...

  5. Vuosaari Harbour Road Tunnel Traffic Management and Incident Detection System Design Issues

    Directory of Open Access Journals (Sweden)

    Caj Holm


    Full Text Available Helsinki is constructing in Vuosaari a new modem and effectivecargo harbour. All cargo harbour activities will be concentratedthere. The total project includes the harbour, a logisticsarea, traffic connections (road, railway and fairway and aBusiness Park. The road connection goes through the Porvarinlahtiroad tunnel. The harbour will commence operatingin 2008. This paper gives an oveTView of the tunnel design phasefunctional studies and risk analysis tunnel incident detectionsystem design issues and some specific environmental featuresof the tunnel.

  6. A method for data base management and analysis for wind tunnel data (United States)

    Biser, Aileen O.


    To respond to the need for improved data base management and analysis capabilities for wind-tunnel data at the Langley 16-Foot Transonic Tunnel, research was conducted into current methods of managing wind-tunnel data and a method was developed as a solution to this need. This paper describes the development of the data base management and analysis method for wind-tunnel data. The design and implementation of the software system are discussed and examples of its use are shown.

  7. Double ionization in the perturbative and tunneling regimes

    Energy Technology Data Exchange (ETDEWEB)

    Walker, B. (Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)); Mevel, E. (Service de Recherches sur les Surfaces et l' Irradiation de la Matiere, Centre d' Etudes Saclay, 91191 Gif-sur-Yvette (France)); Yang, B. (Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)); Breger, P. (Service de Recherches sur les Surfaces et l' Irradiation de la Matiere, Centre d' Etudes de Saclay, 91191 Gif-sur-Yvette (France)); Chambaret, J.P.; Antonetti, A. (Laboratoire d' Optique Appliquee, Ecole Polytechnique, Ecole National Superieure des Techniques Avancees 91120 Palaiseau (France)); DiMauro, L.F. (Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)); Agostini, P. (Service de Recherches sur les Surfaces et l' Irradiation de la Matiere, Centre d' Etudes de Saclay, 91191 Gif-sur-Yvette (France))


    We have studied the doubly charged ion yields and electron energy spectra (normal and coincidence) for double ionization of atoms in two different ionization regimes (perturbative and tunneling). In both cases, the double-ionization rates appear to be anomalously large in some intensity range and strongly reduced by circular polarization. It is argued that these similar behaviors must result from different physical mechanisms.

  8. Tunneling times and excited state interactions between chromophores

    NARCIS (Netherlands)

    Stomphorst, R.


    This Thesis consists of two related parts. The first part (Chapters 2 and 3) presents the results of a fundamental theoretical study of the interpretation of quantum mechanics, and particularly of tunneling processes. Part two (Chapters 4, 5, and 6) describes the experimental results of

  9. Equilibrium and non-equilibrium electron tunneling via discrete quantum states


    Deshmukh, Mandar M.; Bonet, Edgar; Pasupathy, A. N.; Ralph, D. C.


    Tunneling is measured via the quantum levels of a metal nanoparticle. We analyze quantitatively the resonance energies, widths, and amplitudes, both in the regime where only one state is accessible for tunneling and in the non-equilibrium regime when additional states are made accessible one-by-one. For tunneling through one state, our results agree with expectations for sequential tunneling, but in the non-equilibrium regime the resonances are broadened and shifted in ways that require takin...

  10. Carpal Tunnel Release in Diabetic and Non-Diabetic Patients

    Directory of Open Access Journals (Sweden)

    Mohammad H Ebrahimzadeh


    Full Text Available Background: Carpal tunnel syndrome (CTS is a compression neuropathy that causes paresthesia, pain or numbness in the territory of median nerve. The aim of this study is to compare the open surgery outcome and patients` satisfaction in carpal tunnel syndrome among diabetic and non-diabetic patients. Methods: In a retrospective cohort study from April 2011 to June 2012, patients suffered from carpal tunnel syndrome at least 6 months, without response to conservative treatment, who had the inclusion and exclusion criteria, were evaluated by the usage of MHQ and WHOQOL-BREEF tests, one month before surgery and three months after that. Carpal tunnel decompression surgery was performed by two surgeons, experienced in hand surgery, which used the same surgical method. Statistical analysis was performed by SPSS 19.0. Results: 24 of patient (34.2% were male and 46 (65.8% were female and there was no significant difference between two groups (P>0.05. MHQ total score before and after surgery was respectively 50.22±7.13 and 63.49±11.28 and this difference was significant (P

  11. Tunneling and Tunneling Switching Dynamics in Phenol and Ortho-D FTIR Spectroscopy with Synchrotron Radiation and Theory (United States)

    Albert, S.; Prentner, R.; Quack, M.; Lerch, Ph.


    The understanding of tunneling in chemical reactions is of fundamental interest. A particularly intriguing recent development is the theoretical prediction of tunneling switching in ortho-D-phenol (C_6H_4DOH) as opposed to phenol (C_6H_5OH) where only tunneling dominates the dynamics. For ortho-D-phenol at low energy, tunneling is completely suppressed due to isotopic substitution, which introduces an asymmetry in the effective potential including zero point energy. This localizes the molecular wavefunction in either the syn or the anti structure of ortho-D-phenol. At higher torsional states of ortho-D-phenol, tunneling becomes dominant, thus switching the dynamics to a delocalized quantum wavefunction. Therefore, we have investigated the rotationally resolved THz and IR spectra of phenol and ortho-D-phenol measured with our FTIR setup at the Swiss Light Source (SLS) using synchrotron radiation. We have been able to analyse the torsional fundamentals, the first and second overtones of both isotopomers. A comparison of the spectra of phenol and ortho-D-phenol indicates the theoretically predicted behavior of tunneling switching upon excitation of the torsional mode. In detail, we shall discuss the splitting of the torsional fundamental, of its first and second overtones of phenol as well as the fundamentals of syn- and anti- ortho-D-phenol and the possible tunneling switching in the torsional overtone region of ortho-D-phenol. The results shall be also discussed in relation to the quasiadiabatic channel Reaction Path Hamiltonian approach. We shall also discuss the comparison with results for meta-D-phenol. M. Quack, Fundamental symmetries and symmetry violations in Handbook of High Resolution Spectroscopy, Vol. 1(Eds. M. Quack and F. Merkt), Wiley, Chicester (2011), 659-722. S. Albert, Ph. Lerch, R. Prentner, M. Quack, Angew. Chem. Int. Ed. 2013, 52, 346-349. S. Albert and M. Quack, ChemPhysChem, 2007, 8, 1271-1281, S. Albert, K. Keppler Albert and M. Quack, High

  12. Inverse Analysis and Modeling for Tunneling Thrust on Shield Machine

    Directory of Open Access Journals (Sweden)

    Qian Zhang


    Full Text Available With the rapid development of sensor and detection technologies, measured data analysis plays an increasingly important role in the design and control of heavy engineering equipment. The paper proposed a method for inverse analysis and modeling based on mass on-site measured data, in which dimensional analysis and data mining techniques were combined. The method was applied to the modeling of the tunneling thrust on shield machines and an explicit expression for thrust prediction was established. Combined with on-site data from a tunneling project in China, the inverse identification of model coefficients was carried out using the multiple regression method. The model residual was analyzed by statistical methods. By comparing the on-site data and the model predicted results in the other two projects with different tunneling conditions, the feasibility of the model was discussed. The work may provide a scientific basis for the rational design and control of shield tunneling machines and also a new way for mass on-site data analysis of complex engineering systems with nonlinear, multivariable, time-varying characteristics.

  13. Conservation agriculture in high tunnels: soil health and profit enhancement (United States)

    In 2013, through the USDA’s Evans-Allen capacity grant, the high tunnel became an on-farm research laboratory for conservation agriculture. Dr. Manuel R. Reyes, Professor and his research team from the North Carolina Agriculture and Technology State University (NCATSU), Greensboro, North Carolina (1...

  14. Legislative and its requirements to safety of tunnels

    Directory of Open Access Journals (Sweden)

    Peter Grendel


    Full Text Available The article is aimed at the description of legislative and its requirements to safety of tunnels in Slovakia. . The main purposeis analyze Directive of the European Parliament and European Council 2004/54/ES about minimum safety measure at tunnelsin transeuropean route network, which accepts Slovak Republic too within the frame of process harmonization slovak legislative witheuropean legislative.

  15. Extracellular sheets and tunnels modulate glutamate diffusion in hippocampal neuropil. (United States)

    Kinney, Justin P; Spacek, Josef; Bartol, Thomas M; Bajaj, Chandrajit L; Harris, Kristen M; Sejnowski, Terrence J


    Although the extracellular space in the neuropil of the brain is an important channel for volume communication between cells and has other important functions, its morphology on the micron scale has not been analyzed quantitatively owing to experimental limitations. We used manual and computational techniques to reconstruct the 3D geometry of 180 μm(3) of rat CA1 hippocampal neuropil from serial electron microscopy and corrected for tissue shrinkage to reflect the in vivo state. The reconstruction revealed an interconnected network of 40-80 nm diameter tunnels, formed at the junction of three or more cellular processes, spanned by sheets between pairs of cell surfaces with 10-40 nm width. The tunnels tended to occur around synapses and axons, and the sheets were enriched around astrocytes. Monte Carlo simulations of diffusion within the reconstructed neuropil demonstrate that the rate of diffusion of neurotransmitter and other small molecules was slower in sheets than in tunnels. Thus, the non-uniformity found in the extracellular space may have specialized functions for signaling (sheets) and volume transmission (tunnels). Copyright © 2012 Wiley Periodicals, Inc.

  16. Focal choroidal excavation associated with focal retinochoroiditis. (United States)

    Ohki, Tetsutaro; Sakai, Tsutomu; Tsuneoka, Hiroshi


    To describe detailed spectral-domain optical coherence tomography (OCT) findings for two patients with focal choroidal excavation (FCE) associated with focal retinochoroiditis. Three eyes from two patients with FCE associated with focal retinochoroiditis were evaluated by funduscopy, fluorescence angiography, indocyanine green angiography, and spectral-domain OCT during follow-up. Both patients with focal retinochoroiditis developed new FCE after oral steroid treatment and two eyes showed regression of the FCE during the follow-up. Both eyes from one patient transformed from the conforming to the nonconforming type and neither of the eyes were stable during the follow-up. Ultimately, all eyes exhibited the conforming-type FCE. Focal choroidal excavation can be seen as a tomographic phenotype after the treatment of focal retinochoroiditis. Spectral-domain OCT was useful for detecting the development of FCE after the treatment and for observing FCE regression.

  17. 30 CFR 77.211 - Draw-off tunnels; stockpiling and reclaiming operations; general. (United States)


    ... 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 silos...

  18. Tarsal tunnel disease and talocalcaneal coalition: MRI features

    Energy Technology Data Exchange (ETDEWEB)

    FitzGerald Alaia, Erin; Rosenberg, Zehava Sadka; Bencardino, Jenny T.; Ciavarra, Gina A.; Petchprapa, Catherine N. [New York University Langone Medical Center, New York, NY (United States); Rossi, Ignacio [New York University Langone Medical Center, New York, NY (United States); Centro de Diagnostico Dr. Enrique Rossi, Buenos Aires (Argentina)


    To assess, utilizing MRI, tarsal tunnel disease in patients with talocalcaneal coalitions. To the best of our knowledge, this has only anecdotally been described before. Sixty-seven ankle MRIs with talocalcaneal coalition were retrospectively reviewed for disease of tendons and nerves of the tarsal tunnel. Interobserver variability in diagnosing tendon disease was performed in 30 of the 67 cases. Tarsal tunnel nerves were also evaluated in a control group of 20 consecutive ankle MRIs. Entrapment of the flexor hallucis longus tendon (FHL) by osseous excrescences was seen in 14 of 67 cases (21 %). Attenuation, split tearing, tenosynovitis, or tendinosis of the FHL was present in 26 cases (39 %). Attenuation or tenosynovitis was seen in the flexor digitorum longus tendon (FDL) in 18 cases (27 %). Tenosynovitis or split tearing of the posterior tibial tendon (PT) was present in nine cases (13 %). Interobserver variability ranged from 100 % to slight depending on the tendon and type of disease. Intense increased signal and caliber of the medial plantar nerve (MPN), indicative of neuritis, was seen in 6 of the 67 cases (9 %). Mildly increased T2 signal of the MPN was seen in 15 (22 %) and in 14 (70 %) of the control group. Talocalcaneal coalitions may be associated with tarsal tunnel soft tissue abnormalities affecting, in decreasing order, the FHL, FDL, and PT tendons, as well as the MPN. This information should be provided to the referring physician in order to guide treatment and improve post-surgical outcome. (orig.)

  19. Lunar Regolith Excavation Student Competition Design (United States)

    Nething, Julia


    The Surface Systems team is working to learn about lunar regolith and how we can use it as a source of air, water, and fuel for spacecrafts. However, excavation of this valuable regolith is difficult because the robot has to conform to many specifications (mass limit, efficiency level, etc.). NASA has therefore decided to include college students and companies in the search to create the best robot by making it into a competition.

  20. Neutrons and numerical methods. A new look at rotational tunneling

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, M.R.; Kearley, G.J. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)


    Molecular modelling techniques are easily adapted to calculate rotational potentials in crystals of simple molecular compounds. A comparison with the potentials obtained from the tunnelling spectra provides a stringent means for validating current methods of calculating Van der Waals, Coulomb and covalent terms. (author). 5 refs.

  1. Technique of anatomical footprint reconstruction of the ACL with oval tunnels and medial portal aimers. (United States)

    Petersen, Wolf; Forkel, Philipp; Achtnich, Andrea; Metzlaff, Sebastian; Zantop, Thore


    The purpose of this article was to demonstrate an anterior cruciate ligament (ACL) reconstruction technique using oval tunnels. Aim of this single bundle technique is to fit the footprint anatomy of the ACL as closely as possible. TECHNIQUE AND PATIENTS: The presented technique is a single bundle technique using a semitendinosus graft. For femoral tunnel placement, a specific medial portal aimer (Karl Storz, Tuttlingen, Germany) is used. Aiming and drilling of the femoral tunnel are performed via the medial portal. Oval tunnels are created by stepwise dilatation with ovally shaped dilatators. The position of the femoral tunnel is visualized and controlled with the arthroscope via the medial portal. For the tibial tunnel placement, a specific aimer was used as well. With this technique, 24 patients were operated and all intra- and postoperative complications were analyzed prospectively. The tunnel position was documented postoperatively by CT scan. There were no significant intra- and postoperative complications associated with the oval tunnel technique. The postoperative 3D CT scan revealed that all femoral and tibial tunnels were located within the area of the anatomical ACL insertions. This article presents an ACL reconstruction technique using oval dilatators and medial portal aimers to create oval tunnels. These oval tunnels match the insertion site anatomy much closer than round tunnels do. Level IV, case series.

  2. Contribution of static and dynamic ultrasound in cubital tunnel syndrome. (United States)

    Babusiaux, D; Laulan, J; Bouilleau, L; Martin, A; Adrien, C; Aubertin, A; Rabarin, F


    Electroneuromyography (ENMG) is the gold standard examination in cubital tunnel syndrome (CuTS), but sheds no light on etiology. High-resolution ultrasound (HRU) analyzes the anatomic abnormalities and physical properties of the ulnar nerve (UN) and enables dynamic study. The present non-randomized prospective study compared HRU with clinical, ENMG and intraoperative findings. Sixty patients were included. The McGowan clinical classification as modified by Goldberg was employed, and ENMG lesions were ranked for severity. HRU screened for morphologic abnormalities of the ulnar nerve and cubital tunnel, measuring UN cross-sectional area (UNCSA) and flattening index (FI) in the cubital tunnel, in extension and flexion. UN stability was assessed. Ultrasound found 2 stenoses, 29 pseudoneuromas 25 dedifferentiations. There were 16 morphologic abnormalities. Mean cubital tunnel UNCSA (in cm(2)) and FI were respectively 0.112 and 1.549 in extension and 0.117 and 1.827 in flexion. Nineteen cases of UN instability were found on HRU, versus 17 intraoperatively. Only 8 patients showed no abnormality on HRU. Pseudoneuroma or dedifferentiation on HRU correlated with clinical stage (P=0.2579 and 0.2615, respectively). Dedifferentiation was associated with severe abnormality on ENMG (PCubital tunnel UNCSA was elevated in case of CuTS, with cut-off at 0.112 cm(2). FI was elevated in flexion (P=0.0063). The rate of UN instability was 32%, compared to 21-60% in the literature. HRU findings matched the clinical and ENMG classifications. HRU proved to be an effective diagnostic tool for CuTS and its etiologies. IV. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  3. Choroidal neovascularization associated with focal choroidal excavation. (United States)

    Lee, Jae Hyung; Lee, Won Ki


    To describe the clinical and imaging characteristics of choroidal neovascularization (CNV) accompanied by focal choroidal excavation. Retrospective, interventional case series. The medical records of 16 patients (16 eyes) were reviewed. Imaging findings including fluorescein angiography (FA), indocyanine green angiography, and spectral-domain optical coherence tomography (SD OCT) were analyzed. CNV complexes were primarily located beneath the retinal pigment epithelium (type 1 CNV) in 9 eyes and in the subneurosensory retinal space (type 2 CNV) in 7 eyes, as assessed by SD OCT. Seven of 8 patients over 50 years old had type 1 CNV, and 6 of 8 patients under 50 had type 2 lesions. All 7 eyes with type 2 CNV exhibited classic CNV on FA. Additionally, 7 of 9 eyes with type 1 CNV had the classic pattern, and in these eyes, the CNV complexes were confined to the concavity of choroidal excavation. In 15 patients treated by anti-vascular endothelial growth factor (anti-VEGF) injections, the mean best-corrected visual acuity improved from 20/44 to 20/26 with a mean of 3.7 injections during a mean follow-up period of 14.5 months. The CNV growth pattern and extent seem to be determined by the degree of damage to the retinal pigment epithelium/Bruch membrane complex resulting from choroidal excavation, as well as age. Neovascular complexes tend to be located within the boundary of choroidal excavation and are revealed as classic patterns on FA, even in type 1 CNV. Anti-VEGF was notably effective for treating these lesions, with a low rate of recurrence. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Selected aspects of designing deep excavations

    Directory of Open Access Journals (Sweden)

    Obrzud Rafał F.


    Full Text Available This paper analyzes two approaches to serviceability limit state (SLS verification for the deep excavation boundary value problem. The verification is carried out by means of the finite element (FE method with the aid of the commercial program ZSoil v2014. In numerical simulations, deep excavation in non-cohesive soil is supported with a diaphragm wall. In the first approach, the diaphragm wall is modeled with the Hookean material assuming reduced average stiffness and possible concrete cracking. The second approach is divided into two stages. In the first stage, the wall is modeled by defining its stiffness with the highest nominal Young’s modulus. The modulus makes it possible to find design bending moments which are used to compute the minimal design cross-section reinforcement for the retaining structure. The computed reinforcement is then used in a non-linear structural analysis which is viewed as the “actual” SLS verification.

  5. Tunnel and Subsurface Void Detection and Range to Target Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Phillip B. West


    Engineers and technicians at the Idaho National Laboratory invented, designed, built and tested a device capable of detecting and measuring the distance to, an underground void, or tunnel. Preliminary tests demonstrated positive detection of, and range to, a void thru as much as 30 meters of top-soil earth. Device uses acoustic driving point impedance principles pioneered by the Laboratory for well-bore physical properties logging. Data receipts recorded by the device indicates constructive-destructive interference patterns characteristic of acoustic wave reflection from a downward step-change in impedance mismatch. Prototype tests demonstrated that interference patterns in receipt waves could depict the patterns indicative of specific distances. A tool with this capability can quickly (in seconds) indicate the presence and depth/distance of a void or tunnel. Using such a device, border security and military personnel can identify threats of intrusion or weapons caches in most all soil conditions including moist and rocky.

  6. 2D and 3D numerical analysis of tunnel-borne vibration transmission

    NARCIS (Netherlands)

    Geurts, C.P.W.


    For tunnels under densely populated areas, transmission of tunnel-borne vibrations to the earth's surf ace and buildings, is a great concern. To study these phenomena for bored tunnels in soft soil, measurements of the vibration levels caused by impact loads are available. Besides these

  7. Telerobotic excavation system for unexploded ordnance retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Burks, B.L.; Killough, S.M.; Thompson, D.H. [Oak Ridge National Lab., TN (United States). Robotics and Process Systems Div.; Rossi, R.A. [Office of the Project Manager for Ammunition Logistics, Picatinny Arsenal, NJ (United States)


    The small emplacement excavator (SEE) is a ruggedized military vehicle with backhoe and front loader used by the US Army for unexploded ordnance (UXO) retrieval and general utility excavation activities. In order to evaluate the feasibility of removing personnel from the vehicle during high-risk excavation tasks a development and demonstration project was initiated to evaluate performance capabilities of the SEE under telerobotic control. A technology demonstration of the TSEE was conducted at McKinley Range, Redstone Arsenal, Huntsville, Alabama on 13--17 September, 1993. The primary objective of the demonstration was to evaluate and demonstrate the feasibility of remote UXO retrieval. During the demonstration, explosive ordnance disposal specialists were instructed on telerobotic operation of the TSEE, and then were asked to complete a simulated UXO retrieval task. Participants then submitted an evaluation of the system including human factors performance data. This presentation will describe the TSEE, retrieval demonstration, and summarize results of the performance evaluations. Some examples of the results are given below. Seventy percent of the demonstration participants found the tasks were as easy or easier to accomplish utilizing the remote system than with an unmodified system. Similarly, eighty percent of the participants found the TSEE hand controller was as easy or easier to use than the normal manual controls.

  8. Lunar Excavation Experiments in Simulant Soil Test Beds-Revisiting the Surveyor Geotechnical Data (United States)

    Agui, Juan H.; Wilkinson, R. Allen


    (1) Establishing ISRU technologies on planetary bodies is an important long-term goal of NASA; (2) Excavation is a key component of these ISRU processes; (3) Lack of flight data relevant to lunar excavation; (4) Existing models of the excavation-cutting phenomenon give varying results; (5) The lack of predictive models of the dynamic behavior of soils in excavation implements is a major driver for these studies; and (6) Objective: Need to develop robust models of excavation cutting phenomena that generate predictive capabilities to aid the designer and engineer.

  9. Impact-Actuated Digging Tool for Lunar Excavation Project (United States)

    National Aeronautics and Space Administration — Honeybee Robotics proposes to develop a vacuum compatible, impact-actuated digging tool for the excavation of frozen and compacted regolith on the lunar surface and...


    Directory of Open Access Journals (Sweden)

    Bautdinov Damir Tahirovich


    Full Text Available The parametric analysis of the stress state of a transversally isotropic rock mass near a pressurized hydraulic tunnel of a box-shaped form is carried out. Pressurized hydro-technical tunnels of box-shaped cross-section are widely used in the field of hydraulic engineering construction and are one of the complex, labor-intensive and expensive types of structures that make up the main structures of waterworks, melioration systems and water supply systems. As a culvert and water supply facilities they are built underground if the open excavation is impossible or not economical, or when the tunnel runs through a densely populated or densely built-up area, or when landslides, screes, rockfalls are possible. Violation of integrity of the rock mass, in particular, caused by tunneling, modifies the stress-strain state (SSS of the rock mass, which leads to appearance of tensile stresses in some places, and in some cases, to significant compressive stresses. If these stresses exceed the design strengths of rock to tension and compression, respectively, then the collapse of the working roof and buckling of the side walls and the bottom of the tunnel may occur. Subject: analysis of the stress state of transversally isotropic rocks near the pressurized hydraulic tunnel of horseshoe cross-section caused by the internal head of water. Research objectives: determination of real values of circumferential stresses along the development contour. Materials and methods: solution of the problem of plane deformation of the theory of elasticity for a transversely isotropic medium containing tunnel excavation cannot be obtained by analytical methods, and therefore the stress-strain analysis was carried out by the finite element method using the ANSYS software package, MCE. Results: determination of stresses along the development contour, construction of diagrams and graphs showing the effects of the anisotropy conditions and Poisson’s ratio. The tangential stresses

  11. Continuous section extraction and over-underbreak detection of tunnel based on 3D laser technology and image analysis (United States)

    Wang, Weixing; Wang, Zhiwei; Han, Ya; Li, Shuang; Zhang, Xin


    In order to ensure safety, long term stability and quality control in modern tunneling operations, the acquisition of geotechnical information about encountered rock conditions and detailed installed support information is required. The limited space and time in an operational tunnel environment make the acquiring data challenging. The laser scanning in a tunneling environment, however, shows a great potential. The surveying and mapping of tunnels are crucial for the optimal use after construction and in routine inspections. Most of these applications focus on the geometric information of the tunnels extracted from the laser scanning data. There are two kinds of applications widely discussed: deformation measurement and feature extraction. The traditional deformation measurement in an underground environment is performed with a series of permanent control points installed around the profile of an excavation, which is unsuitable for a global consideration of the investigated area. Using laser scanning for deformation analysis provides many benefits as compared to traditional monitoring techniques. The change in profile is able to be fully characterized and the areas of the anomalous movement can easily be separated from overall trends due to the high density of the point cloud data. Furthermore, monitoring with a laser scanner does not require the permanent installation of control points, therefore the monitoring can be completed more quickly after excavation, and the scanning is non-contact, hence, no damage is done during the installation of temporary control points. The main drawback of using the laser scanning for deformation monitoring is that the point accuracy of the original data is generally the same magnitude as the smallest level of deformations that are to be measured. To overcome this, statistical techniques and three dimensional image processing techniques for the point clouds must be developed. For safely, effectively and easily control the problem of

  12. Strained silicon and silicon germanium nanowire tunnel FETs and inverters


    Richter, Simon


    Reducing power consumption is an important issue for integrated circuits in portable devices relying on batteries and systems without external power supply. Scaling of the supply voltage VDD in integrated circuits is a powerful tool for reducing the power consumption, due to the quadratic dependence on VDD. MOSFETs, however, exhibit a fundamental limitation for the drain current increase per applied gate voltage difference. The tunnel field-effect transistor (TFET) provides the ability for be...

  13. Evaluation of TBM tunnels with respect to stability against spalling (United States)

    Shaalan, Heyam; Ismail, Mohd Ashraf Mohd; Azit, Romziah


    As the depth of tunnels and underground construction increases, instability occurs in the form of rock bursting or spalling because of the induced stresses. Spalling may appear as a strong compressive stress causing crack growth behind the excavated surface and buckling of the thin rock slabs. In this paper, we describe how to reduce the rock spalling failure to increase the underground safety and the tunnel stability. Thus, a parametric study is implemented using 2-D Elasto-plastic finite elements stress analysis software to investigate the parameters that can minimize the extent and depth of the failure zone. The critical section of Pahang Selangor Raw Water Transfer Tunnel under high overburden is analyzed. The effect of the shotcrete lining thickness, tunnel size and the removal of fallouts or scaled v-notch on the failure zone depth is investigated. The results demonstrate that the shotcrete lining thickness has less influence on the failure depth, while a small tunnel diameter minimizes the failure depth. In addition, the stability of the tunnel improves by removing the loose rock mass.

  14. The forecast of mining-induced seismicity and the consequent risk of damage to the excavation in the area of seismic event

    Directory of Open Access Journals (Sweden)

    Jan Drzewiecki


    Full Text Available The Central Mining Institute has developed a method for forecasting the amount of seismic energy created by tremors induced by mining operations. The results of geophysical measurements of S wave velocity anomalies in a rock mass or the results of analytic calculations of the values of pressure on the horizon of the elastic layers are used in the process of calculating the energy. The calculation program which has been developed and adopted has been modified over recent years and it now enables not only the prediction of the energy of dynamic phenomena induced by mining but also the forecasting of the devastating range of seismic shock. The results obtained from this calculation, usually presented in a more readable graphic form, are useful for the macroscopic evaluation of locations that are potential sources of seismic energy. Forecasting of the maximum energy of seismic shock without prior knowledge of the location of the shock's source, does not allow shock attenuation that results from, for example, a distance of tremor source from the excavati