Crustal Deformation around Zhangjiakou-Bohai Seismically Active Belt

Science.gov (United States)

Jin, H.; Fu, G.; Kato, T.

2011-12-01

Zhangjiakou-Bohai belt is a seismically active belt located in Northern China around Beijing, the capital of China. Near such a belt many great earthquakes occurred in the past centuries (e.g. the 1976 Tanshan Ms7.8 earthquake, the 1998 Zhangbei Ms6.2 earthquake, etc). Chinese Government established dense permanent and regional Global Positioning System (GPS) stations in and near the area. We collected and analyzed all the GPS observation data between 1999 and 2009 around Zhangjiakou-Bohai seismic belt, and obtained velocities at 143 stations. At the same time we investigated Zhangjiakou-Bohai belt slip rate for three profiles from northwest to southeast, and constructed a regional strain field on the Zhangjiakou-Bohai seismic belt region by least-square collocation. Based on the study we found that: 1) Nowadays the Zhangjiakou-Bohai seismic belt is creeping with left-lateral slip rate of 2.0mm~2.4mm/a, with coupling depth of 35~50km; 2) In total, the slip and coupling depth of the northwestern seismic belt is less than the one of southeast side; 3) The maximum shear strain is about 3×10-8 at Beijing-Tianjin-Tangshan area.

Electron tunneling in chemistry

International Nuclear Information System (INIS)

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

1985-01-01

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

Optimal control of operation efficiency of belt conveyor systems

International Nuclear Information System (INIS)

Zhang, Shirong; Xia, Xiaohua

2010-01-01

The improvement of the energy efficiency of belt conveyor systems can be achieved at equipment or operation levels. Switching control and variable speed control are proposed in literature to improve energy efficiency of belt conveyors. The current implementations mostly focus on lower level control loops or an individual belt conveyor without operational considerations at the system level. In this paper, an optimal switching control and a variable speed drive (VSD) based optimal control are proposed to improve the energy efficiency of belt conveyor systems at the operational level, where time-of-use (TOU) tariff, ramp rate of belt speed and other system constraints are considered. A coal conveying system in a coal-fired power plant is taken as a case study, where great saving of energy cost is achieved by the two optimal control strategies. Moreover, considerable energy saving resulting from VSD based optimal control is also proved by the case study.

Optimal control of operation efficiency of belt conveyor systems

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shirong [Department of Automation, Wuhan University, Wuhan 430072 (China); Xia, Xiaohua [Department of Electrical, Electronic and Computer Engineering, University of Pretoria, Pretoria 0002 (South Africa)

2010-06-15

The improvement of the energy efficiency of belt conveyor systems can be achieved at equipment or operation levels. Switching control and variable speed control are proposed in literature to improve energy efficiency of belt conveyors. The current implementations mostly focus on lower level control loops or an individual belt conveyor without operational considerations at the system level. In this paper, an optimal switching control and a variable speed drive (VSD) based optimal control are proposed to improve the energy efficiency of belt conveyor systems at the operational level, where time-of-use (TOU) tariff, ramp rate of belt speed and other system constraints are considered. A coal conveying system in a coal-fired power plant is taken as a case study, where great saving of energy cost is achieved by the two optimal control strategies. Moreover, considerable energy saving resulting from VSD based optimal control is also proved by the case study. (author)

Design aspects of multiple driven belt conveyors

NARCIS (Netherlands)

Nuttall, A.J.G.

2007-01-01

Worldwide belt conveyors are used to transport a great variety of bulk solid materials. The desire to carry higher tonnages over longer distances and more diverse routes, while keeping exploitation costs as low as possible, has fuelled many technological advances. An interesting development in the

New generation of free-piston shock tunnels

Science.gov (United States)

Morrison, W. R. B.; Stalker, R. J.; Duffin, J.

1990-01-01

Consideration is given to three free-piston driven hypersonic tunnels under construction that will greatly enhance existing test capabilities. The tunnel being built at Caltech will feature energy capabilities about 40 percent higher than those of the world's largest operational free-piston tunnel to date. The second tunnel under construction will allow full-size engine hardware at near-orbital speeds. The third facility is a high-performance expansion tube that will be capable of generating high enthalpy flows at speeds of up to 9 km/sec. It will provide flows with dissociation levels much lower than are attainable with a reflected shock tunnel, approaching actual flight conditions. A table shows the tunnels' characteristics.

New developments of belt conveyor systems; Inclined belt systems, vertical pipe elevators, vibration belts, oscillating tubes

Energy Technology Data Exchange (ETDEWEB)

Bahke, E.A. (Universitaet Karlsruhe, Karlsruhe (Germany, F.R.). Inst. fuer Foerdertechnik)

1991-03-01

Factors that have influenced the design of belt conveyor systems are discussed - these include strength and shaping. Belt conveyor systems for inclined, steep-angle and vertical conveying are described and comparison made between cable belt and steel cord belt conveyors used in coal mines. Hose-belt or tube conveyors such as are used in the PWH/Conti-Rollgurt Conveyor System for feeding boilers in German coal fired power stations are mentioned and advantages of the pipe-belt conveyor for vertical transport discussed. Design of the vibratory conveyor for transporting solids upwards by pulses is described. 29 refs., 19 figs., 2 tabs.

Tunnel magnetoresistance in thermally robust Mo/CoFeB/MgO tunnel junction with perpendicular magnetic anisotropy

Directory of Open Access Journals (Sweden)

B. Fang

2015-06-01

Full Text Available We report on tunnel magnetoresistance and electric-field effect in the Mo buffered and capped CoFeB/MgO magnetic tunnel junctions (MTJs with perpendicular magnetic anisotropy. A large tunnel magnetoresistance of 120% is achieved. Furthermore, this structure shows greatly improved thermal stability and stronger electric-field-induced modulation effect in comparison with the Ta/CoFeB/MgO-based MTJs. These results suggest that the Mo-based MTJs are more desirable for next generation spintronic devices.

Explaining state-to-state differences in seat belt use : an analysis of socio-demographic variables.

Science.gov (United States)

2011-02-01

"Despite the extensive evidence about the benefits of seat belt use, there is a great deal of variation in use within the US. For example, the national average for seat belt use in 2009 was 84 percent while the state-level averages ranged from 68 per...

Potential for production of ‘mini-mussels’ in Great Belt (Denmark) evaluated on basis of actual and modeled growth of young mussels Mytilus edulis

DEFF Research Database (Denmark)

Riisgård, Hans Ulrik; Lundgreen, Kim; Larsen, Poul Scheel

2014-01-01

The present study is a first step towards evaluation of the potential for line-mussel production in the Great Belt region between the Kattegat and Baltic Sea, Denmark. We present experimental results for actual growth rates of juvenile/adult mussels Mytilus edulis in suspended net bags in terms......) as a function of dry weight of soft parts (W, g) by a previously developed simple bioenergetic growth model μ = aW −0.34. Results were generally in good agreement with the model which assumes the prevailing average chlorophyll a concentration at field sites to essentially account for the nutrition. Our studies...

IDENTIFYING COLLISIONAL FAMILIES IN THE KUIPER BELT

International Nuclear Information System (INIS)

Marcus, Robert A.; Ragozzine, Darin; Murray-Clay, Ruth A.; Holman, Matthew J.

2011-01-01

The identification and characterization of numerous collisional families-clusters of bodies with a common collisional origin-in the asteroid belt has added greatly to the understanding of asteroid belt formation and evolution. More recent study has also led to an appreciation of physical processes that had previously been neglected (e.g., the Yarkovsky effect). Collisions have certainly played an important role in the evolution of the Kuiper Belt as well, though only one collisional family has been identified in that region to date, around the dwarf planet Haumea. In this paper, we combine insights into collisional families from numerical simulations with the current observational constraints on the dynamical structure of the Kuiper Belt to investigate the ideal sizes and locations for identifying collisional families. We find that larger progenitors (r ∼ 500 km) result in more easily identifiable families, given the difficulty in identifying fragments of smaller progenitors in magnitude-limited surveys, despite their larger spread and less frequent occurrence. However, even these families do not stand out well from the background. Identifying families as statistical overdensities is much easier than characterizing families by distinguishing individual members from interlopers. Such identification seems promising, provided the background population is well known. In either case, families will also be much easier to study where the background population is small, i.e., at high inclinations. Overall, our results indicate that entirely different techniques for identifying families will be needed for the Kuiper Belt, and we provide some suggestions.

The Security Challenges of the “One Belt, One Road” Initiative and China’s Choices

OpenAIRE

Haiquan, Liu

2017-01-01

The Silk Road Economic Belt and the 21st Century Maritime Silk Road initiatives (“One Belt, One Road”) are of significance in enhancing China’s open economy. This article explores the dual security challenges faced by the “One Belt, One Road” initiative. These challenges include both traditional security challenges, such as great power competition, territorial and island disputes, and political turmoil in the region, as well as non-traditional threats such as terrorism, piracy, and transnatio...

30 CFR 75.1731 - Maintenance of belt conveyors and belt conveyor entries.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maintenance of belt conveyors and belt conveyor....1731 Maintenance of belt conveyors and belt conveyor entries. (a) Damaged rollers, or other damaged belt conveyor components, which pose a fire hazard must be immediately repaired or replaced. All other...

Lap belts and three-point belts.

NARCIS (Netherlands)

Kampen, L.T.B. van & Edelman, A.

1975-01-01

Results of the swov-accident investigation prove that if there are any differences in the effectiveness of lap belts and three-point belts, these are so small that they cannot form a basis for giving preference to one type over the other. Furthermore, in spite of the results of this investigation

Simulation of engine auxiliary drive V-belt slip motion. Part 1. Development of belt slip model; Engine hoki V belt slip kyodo no simulation. 1. Belt slip model no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Kurisu, T [Mazda Motor Corp., Hiroshima (Japan)

1997-10-01

V-belts are widely used for driving auxiliary components of an engine. Inadequet design of such belt system sometimes results in troubles such as belt squeak, side rubber separation and/or bottom rubber crack. However, there has been no design tools which can predict belt slip quantitatively. The author developed a motion simulation program of Auxiliary Drive V-Belt System considering belt slip. The program showed good prediction accuracy for belt slip motion. This paper describes the simulation model. 1 ref., 12 figs.

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

International Nuclear Information System (INIS)

Cleland, A.N.

1991-04-01

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

Seat belt reminders.

NARCIS (Netherlands)

2008-01-01

Seat belts are an effective way of reducing the number or road deaths and severe road injuries in crashes. Seat belt reminders warn car drivers and passengers if the seat belt is not fastened. This can be done by a visual signal or an acoustic signal or by a combination of the two. Seat belt

Belt Aligning Revisited

Directory of Open Access Journals (Sweden)

Yurchenko Vadim

2017-01-01

parts of the conveyor, the sides of the belt wear intensively. This results in reducing the life of the belt. The reasons for this phenomenon are well investigated, but the difficulty lies in the fact that they all act simultaneously. The belt misalignment prevention can be carried out in two ways: by minimizing the effect of causes and by aligning the belt. The construction of aligning devices and errors encountered in practice are considered in this paper. Self-aligning roller supports rotational in plan view are recommended as a means of combating the belt misalignment.

Condition-Based Conveyor Belt Replacement Strategy in Lignite Mines with Random Belt Deterioration

Science.gov (United States)

Blazej, Ryszard; Jurdziak, Leszek

2017-12-01

In Polish lignite surface mines, condition-based belt replacement strategies are applied in order to assure profitable refurbishment of worn out belts performed by external firms specializing in belt maintenance. In two of three lignite mines, staff asses belt condition subjectively during visual inspections. Only one mine applies specialized diagnostic device (HRDS) allowing objective magnetic evaluation of belt core condition in order to choose the most profitable moment for the dismantling of worn out belt segments from conveyors and sending them to the maintenance firm which provides their refurbishment. This article describes the advantages of a new diagnostic device called DiagBelt. It was developed at the Faculty of Geoengineering, Mining and Geology, Wroclaw University of Science and Technology. Economic gains from its application are calculated for the lignite mine and for the belt maintenance firm, taking into account random life (durability) of new and reconditioned belts (after the 1st and the 2nd refurbishment). Recursive calculations for following years allow the estimation of the length and costs of replaced, reconditioned and purchased belts on an annual basis, while the use of the Monte Carlo method allows the estimation of their variability caused by random deterioration of belts. Savings are obtained due to better selection of moments (times) for the replacement of belt segments and die to the possibility to qualify worn out belts for refurbishment without the need to remove their covers. In effect, increased belt durability and lowered share of waste belts (which were not qualified for reconditioning) create savings which can quickly cover expenditures on new diagnostic tools and regular belt inspections in the mine.

Infrastructure becomes a energy source. Tunnel projects for power generation; Infrastruktur wird zur Energiequelle. Tunnelprojekte zur Energiegewinnung

Energy Technology Data Exchange (ETDEWEB)

Winterling, Ralf [Rehau AG + Co, Erlangen (Germany). Abt. Traffic Route Engineering

2012-07-15

Tunnel structures offer a great potential for power generation from the surrounding soil as well as from the tunnel itself due to the tunnel operation. Some tunnel projects already are being used for the purpose of power generation for above-ground applications. Therefore, in recent years various technologies have been developed. Firstly, energy can be produced from underground water. On the other hand, primarily absorber systems offer great potential for power generation with tubbing. This is just given to city tunnels where underground water can be utilized restrictedly.

Effectiveness of Ford's belt reminder system in increasing seat belt use

OpenAIRE

Williams, A; Wells, J; Farmer, C

2002-01-01

Objectives: The study investigated the effectiveness in increasing seat belt use of Ford's belt reminder system, a supplementary system that provides intermittent flashing lights and chimes for five minutes if drivers are not belted.

Storm-time radiation belt electron dynamics: Repeatability in the outer radiation belt

Science.gov (United States)

Murphy, K. R.; Mann, I. R.; Rae, J.; Watt, C.; Boyd, A. J.; Turner, D. L.; Claudepierre, S. G.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Blake, J. B.; Fennell, J. F.

2017-12-01

During intervals of enhanced solar wind driving the outer radiation belt becomes extremely dynamic leading to geomagnetic storms. During these storms the flux of energetic electrons can vary by over 4 orders of magnitude. Despite recent advances in understanding the nature of competing storm-time electron loss and acceleration processes the dynamic behavior of the outer radiation belt remains poorly understood; the outer radiation belt can exhibit either no change, an enhancement, or depletion in radiation belt electrons. Using a new analysis of the total radiation belt electron content, calculated from the Van Allen probes phase space density (PSD), we statistically analyze the time-dependent and global response of the outer radiation belt during storms. We demonstrate that by removing adiabatic effects there is a clear and repeatable sequence of events in storm-time radiation belt electron dynamics. Namely, the relativistic (μ=1000 MeV/G) and ultra-relativistic (μ=4000 MeV/G) electron populations can be separated into two phases; an initial phase dominated by loss followed by a second phase dominated by acceleration. At lower energies, the radiation belt seed population of electrons (μ=150 MeV/G) shows no evidence of loss but rather a net enhancement during storms. Further, we investigate the dependence of electron dynamics as a function of the second adiabatic invariant, K. These results demonstrate a global coherency in the dynamics of the source, relativistic and ultra-relativistic electron populations as function of the second adiabatic invariant K. This analysis demonstrates two key aspects of storm-time radiation belt electron dynamics. First, the radiation belt responds repeatably to solar wind driving during geomagnetic storms. Second, the response of the radiation belt is energy dependent, relativistic electrons behaving differently than lower energy seed electrons. These results have important implications in radiation belt research. In particular

Belt attachment and system

Energy Technology Data Exchange (ETDEWEB)

Schneider, Abraham D.; Davidson, Erick M.

2018-03-06

Disclosed herein is a belt assembly including a flexible belt with an improved belt attachment. The belt attachment includes two crossbars spaced along the length of the belt. The crossbars retain bearings that allow predetermined movement in six degrees of freedom. The crossbars are connected by a rigid body that attaches to the bearings. Implements that are attached to the rigid body are simply supported but restrained in pitching rotation.

Electrical control of memristance and magnetoresistance in oxide magnetic tunnel junctions

KAUST Repository

Zhang, Kun; Cao, Yan-ling; Fang, Yue-wen; Li, Qiang; Zhang, Jie; Duan, Chun-gang; Yan, Shi-shen; Tian, Yu-feng; Huang, Rong; Zheng, Rong-kun; Kang, Shi-shou; Chen, Yan-xue; Liu, Guo-lei; Mei, Liang-mo

2015-01-01

, and exchange bias in Co/CoO–ZnO/Co magnetic tunnel junctions, which enables the realization of four nonvolatile resistance states. Moreover, greatly enhanced tunneling magnetoresistance of 68% was observed due to the enhanced spin polarization of the bottom Co/Co

Restraint use by car occupants: Great Britain, 1982-91.

NARCIS (Netherlands)

Broughton, J.

1992-01-01

One of the major developments in road safety in Great Britain during the last decade has been the increasing use of seat belts by people travelling in cars. This has been achieved by legislation, with supporting publicity.

Riding the belt

Energy Technology Data Exchange (ETDEWEB)

Potts, A

1998-04-01

Recent developments in conveyor systems have focused on accessories rather than the belt itself. Radio frequency identification (RFID) is a technology using transponders embedded in conveyor belts and this is the latest development at the German firm Contitech. The system described in the articles developed with Moers, features transponders for cooling, controlling and monitoring conveyor belts. Other developments mentioned include a JOKI drum motor featuring a fully integrated gearbox and electric motor enclosed in a steel shell, from Interoll; a new scraper cleaning system from Hosch, new steel cord belting from Fenner, a conveying system for Schleenhain lignite opencast mine by FAM Foerdelantigen Magdeburg; new bearings from Nadella (the sales arm of Intersoll-Rand), an anti-shock belt transfer table from Rosta and new caliper disc brakes from GE Industrial.

Synaptic ribbon. Conveyor belt or safety belt?

Science.gov (United States)

Parsons, T D; Sterling, P

2003-02-06

The synaptic ribbon in neurons that release transmitter via graded potentials has been considered as a conveyor belt that actively moves vesicles toward their release sites. But evidence has accumulated to the contrary, and it now seems plausible that the ribbon serves instead as a safety belt to tether vesicles stably in mutual contact and thus facilitate multivesicular release by compound exocytosis.

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Coherent tunnelling conductance in normal-metal/d-wave superconductor/normal-metal double tunnel junctions

International Nuclear Information System (INIS)

Dong, Z C; Zheng, Z M; Xing, D Y

2004-01-01

Taking simultaneously into account the electron-injected current from one normal-metal (N) electrode and the hole-injected current from the other N electrode, we study the coherent tunnelling conductance and quantum interference effects in N/d-wave superconductor (S)/N double tunnel junctions. It is found that oscillations of all quasiparticle transport coefficients and the conductance spectrum with quasiparticle energy and thickness of the d-wave S depend to a great extent on the crystal orientation of the d-wave S. The zero-bias conductance peak is gradually lowered with increasing barrier strength and/or temperature, its magnitude exhibiting damped oscillatory behaviour with thickness of S

Effects of Electromagnetic Perturbations on Particles Trapped in the Radiation Belts

Energy Technology Data Exchange (ETDEWEB)

Dungey, J. W. [Imperial College of Science and Technology, London (United Kingdom)

1965-06-15

Since the radiation belts were discovered by Van Allen in 1958, observations of trapped particles have rapidly built up a large body of information. Knowledge of the neutral atmosphere as well as the ionosphere shows that for energetic particles the probable time before colliding with another particle of any kind may be extremely long. Then the only feature known to affect the motion of the particle is the electromagnetic field and, conversely, over a long time even weak electromagnetic disturbances can be important. Consequently, electromagnetic disturbances should be important in determining the form of the radiation belts, and it will be seen that certain features encourage an interpretation of this kind. The physics of the radiation belts may be regarded as a part of plasma physics, namely the realm in which collisions are negligible. This needs qualifying in that there is a boundary layer (the ionosphere) where collisions are important, and this is analogous to laboratory plasma containment devices. The energy range of trapped particles is wide, but includes the energy range required for fusion reactors. The mean free time in the radiation belts is extreme, but the neglect of collisions yields a great simplification in theoretical work, and an understanding of collision-free plasmas is expected to be useful. Observations in space have great advantages. The quantity measured by a particle-detector sensitive to a limited range of energy and with a limited cone of acceptance is the velocity distribution function, which is fundamental in theoretical work. Local electric and magnetic measurements are also made with very little disturbance by the spacecraft. The disadvantage is that simultaneous measurements cannot be made at many different points.

Earth's radiation belts

International Nuclear Information System (INIS)

Moslehi Fard, M.

1984-01-01

The theory of trapped particles in a magnetic field of approximated dipole is described completely in the first part. Second part contains experimental results. The mechanism of radiation belt source ''albedo neutrons'' and also types of dissipation mechanism about radiation belt is explained. The trapped protons and electrons by radiation belt is discussed and the life-time of trapped particles are presented. Finally the magnetic fields of Moon, Venus, Mars, and Saturn, measured by passengers Mariner 4,10 and pioneer 10,11 are indicated. The experimental and theoretical results for the explanation of trapped plasma around the earth which is looked like two internal and external belt have almost good correspondence

Dynamics Analysis and Modeling of Rubber Belt in Large Mine Belt Conveyors

OpenAIRE

Gao Yang

2014-01-01

Rubber belt not only is one of the key components of belt conveyor, but also affects the overall performance of the core part. Research on dynamics analysis of large conveyor not only helps to improve the reliability and design level, but also can guide the rational selection of conveyor safety factor, and effectively reduce the cost of the conveyor belt. Based on unique viscoelastic properties of belt conveyor, it was simplified as one-dimensional viscoelastic rod in this study, and then a d...

The Security Challenges of the “One Belt, One Road” Initiative and China’s Choices

Directory of Open Access Journals (Sweden)

Haiquan Liu

2017-08-01

Full Text Available The Silk Road Economic Belt and the 21st Century Maritime Silk Road initiatives (“One Belt, One Road” are of significance in enhancing China’s open economy. This article explores the dual security challenges faced by the “One Belt, One Road” initiative. These challenges include both traditional security challenges, such as great power competition, territorial and island disputes, and political turmoil in the region, as well as non-traditional threats such as terrorism, piracy, and transnational organized crime. This article analyzes the present situation of security cooperation in the region covered by “One Belt, One Road” and also suggests that China needs to pay special attention to three issues, namely the supply of public security goods, the interests of the United States and Russia, and the pivot of Pakistan, besides developing its own strength.

20 January 2014 - Members of the Regional Assemblies and Parliaments United Kingdom of Great Britain and Northern Ireland visiting the LHC tunnel at Point 8 with Technology Department, Vacuum, Surfaces and Coatings Group P. Cruikshank.

CERN Document Server

Pantelia, Anna

2014-01-01

20 January 2014 - Members of the Regional Assemblies and Parliaments United Kingdom of Great Britain and Northern Ireland visiting the LHC tunnel at Point 8 with Technology Department, Vacuum, Surfaces and Coatings Group P. Cruikshank.

Tunnel boring an alternative method in construction of spent fuel repositories

International Nuclear Information System (INIS)

Christersson, Jukka

1984-05-01

In projecting of the final disposal of nuclear waste in geological formations a great importance should be paid to the selection of the tunneling method. The environment of the chosen repository area should not be exposed to any but as minor disturbances as possible by the excavation method applied. This study approaches full face tunneling methods as an alternative to conventional drill-and-blast methods in the construction of spent fuel repository tunnels. According to experiences up till now it is obvious, that tunnelboring today is fully capable technically competing with conventional tunneling methods, even in the hardest granitic rocks. The most important advantages, it provides for the construction of repositories, are: The methods does not produce any damage in the surrounding rock. Possibility to use placement techniques, which do not require preparing of additive repository holes for the fuel elements. Saving in the use of expensive filling material. The fact, that tunnel boring in hard rock is an expensive alternative, is still valid. Constuction of straight lined tunnels in unfractured rocks by tunnel boring would cost about 30-40% more than by conventional methods. The lay out arrangement of bored tunnels still have a great influence on tunnel boring machine's economy. Due to this it would be round 40-70% more expensive method in the construction of spent fuel repositories. However intensive development w is being carried out to eliminate these limitations and to make machines more flexible. Future trends in tunnel boring look good at the moment. The number of sold units has been increasing and new applications have widen out during last ten years. Harder and more abrasive rocks can now be bored than ever before and the trend seems to continue. It also looks like the cost difference in the hardest rocks is firmly getting smaller and smaller all the time. (author)

Belt conveyor apparatus

Science.gov (United States)

Oakley, David J.; Bogart, Rex L.

1987-01-01

A belt conveyor apparatus according to this invention defines a conveyance path including a first pulley and at least a second pulley. An endless belt member is adapted for continuous travel about the pulleys and comprises a lower portion which engages the pulleys and an integral upper portion adapted to receive objects therein at a first location on said conveyance path and transport the objects to a second location for discharge. The upper belt portion includes an opposed pair of longitudinally disposed crest-like members, biased towards each other in a substantially abutting relationship. The crest-like members define therebetween a continuous, normally biased closed, channel along the upper belt portion. Means are disposed at the first and second locations and operatively associated with the belt member for urging the normally biased together crest-like members apart in order to provide access to the continuous channel whereby objects can be received into, or discharged from the channel. Motors are in communication with the conveyance path for effecting the travel of the endless belt member about the conveyance path. The conveyance path can be configured to include travel through two or more elevations and one or more directional changes in order to convey objects above, below and/or around existing structures.

Triggering Artefacts

DEFF Research Database (Denmark)

Mogensen, Preben Holst; Robinson, Mike

1995-01-01

and adapting them to specific situations need not be ad hoc.Triggering artefacts are a way of systematically challenging both designers' preunderstandings and the conservatism of work practice. Experiences from the Great Belt tunnel and bridge project are used to illustrate howtriggering artefacts change...

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

Science.gov (United States)

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

2010-01-01

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

An evaluation of a weightlifting belt and back injury prevention training class for airline baggage handlers.

Science.gov (United States)

Reddell, C R; Congleton, J J; Dale Huchingson, R; Montgomery, J F

1992-10-01

This study evaluated the efficacy of a commercially available weightlifting belt in relation to reduction of lumbar injury incident rate and severity of injuries over an 8-month period. The study used 642 baggage handlers working for a major airline company as participants. Four treatment groups were randomly selected: a group receiving the belt only, a group receiving a 1 h training class only, a group receiving both a belt and a 1 h training class, and a control group receiving nothing. Two treatment groups were added which contained participants who discontinued use of the belt prior to the end of an 8-month study period. Results indicated that there were no significant differences for total lumbar injury incident rate, restricted workday case injury incident rate, lost workdays and restricted workdays rate, and worker's compensation rates. There was, however, a marginal significant difference for lost workday case injury incident rate. Groups with participants who wore the belt for a while then discontinued its use had a higher lost day case injury incident rate than did either the group receiving training only or the control group. Compliance was an overriding factor as the belt questionnaire response indicated that 58% of participants in the belt groups discontinued use of the belt before the end of 8 months. Comments made on the survey forms indicated that the belt was too hot. Similarly, comments suggested that the belt rubbed, pinched, and bruised ribs. Based on these results, the weightlifting belt used for this study cannot be recommended for use in aid of lifting during daily work activities of baggage handlers. Results indicate that use of the belts may, in fact, increase the risk of injury when not wearing a belt following a period of wearing a belt. As industries are experimenting with the use of belts, it is recommended that great care be taken in any further evaluation and close attention directed towards injuries which occur when not wearing the

Impact of Selected Parameters on the Fatigue Strength of Splices on Multiply Textile Conveyor Belts

Science.gov (United States)

Bajda, Mirosław; Błażej, Ryszard; Hardygóra, Monika

2016-10-01

Splices are the weakest points in the conveyor belt loop. The strength of these joints, and thus their design as well as the method and quality of splicing, determine the strength of the whole conveyor belt loop. A special zone in a splice exists, where the stresses in the adjacent plies or cables differ considerably from each other. This results in differences in the elongation of these elements and in additional shearing stresses in the rubber layer. The strength of the joints depends on several factors, among others on the parameters of the joined belt, on the connecting layer and the technology of joining, as well as on the materials used to make the joint. The strength of the joint constitutes a criterion for the selection of a belt suitable for the operating conditions, and therefore methods of testing such joints are of great importance. This paper presents the method of testing fatigue strength of splices made on multi-ply textile conveyor belts and the results of these studies.

Analysis of tensile strain enhancement in Ge nano-belts on an insulator surrounded by dielectrics

International Nuclear Information System (INIS)

Lu Wei-Fang; Li Cheng; Huang Shi-Hao; Lin Guang-Yang; Wang Chen; Yan Guang-Ming; Huang Wei; Lai Hong-Kai; Chen Song-Yan

2013-01-01

Ge nano-belts with large tensile strain are considered as one of the promising materials for high carrier mobility metal—oxide—semiconductor transistors and efficient photonic devices. In this paper, we design the Ge nano-belts on an insulator surrounded by Si 3 N 4 or SiO 2 for improving their tensile strain and simulate the strain profiles by using the finite difference time domain (FDTD) method. The width and thickness parameters of Ge nano-belts on an insulator, which have great effects on the strain profile, are optimized. A large uniaxial tensile strain of 1.16% in 50-nm width and 12-nm thickness Ge nano-belts with the sidewalls protected by Si 3 N 4 is achieved after thermal treatments, which would significantly tailor the band gap structures of Ge-nanobelts to realize the high performance devices. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Analysis of stress distribution of timing belts by FEM; Yugen yosoho ni yoru timing belt oryoku kaiseki (belt code oryoku bunpu kaiseki hokoku)

Energy Technology Data Exchange (ETDEWEB)

Furukawa, Y; Tomono, K; Takahashi, H; Uchida, T [Honda R and D Co. Ltd., Tokyo (Japan)

1997-10-01

A model of the belt analyzed by-ABAQUS (: a general nonlinear finite element program) successfully confirmed the mechanism that generates the belt cord stress. A quite good agreement between experimental and computed results for the stress distribution of the belt cord. It is found that maximum stress of the cords occurs near the root of the tooth by calculation, where the belt cords break off. 3 refs., 9 figs.

Atmospheres and surfaces of small bodies and dwarf planets in the Kuiper Belt

Directory of Open Access Journals (Sweden)

Schaller E.L.

2010-12-01

Full Text Available Kuiper Belt Objects (KBOs are icy relics orbiting the sun beyond Neptune left over from the planetary accretion disk. These bodies act as unique tracers of the chemical, thermal, and dynamical history of our solar system. Over 1000 Kuiper Belt Objects (KBOs and centaurs (objects with perihelia between the giant planets have been discovered over the past two decades. While the vast majority of these objects are small ( 6-meter telescopes, have allowed for the first detailed studies of their surfaces and atmospheres. Visible and near-infrared spectroscopy of KBOs and centaurs has revealed a great diversity of surface compositions. Only the largest and coldest objects are capable of retaining volatile ices and atmospheres. Knowledge of the dynamics, physical properties, and collisional history of objects in the Kuiper belt is important for understanding solar system formation and evolution.

Fire safety case study of a railway tunnel: Smoke evacuation

Directory of Open Access Journals (Sweden)

van Maele Karim

2007-01-01

Full Text Available When a fire occurs in a tunnel, it is of great importance to assure the safety of the occupants of the tunnel. This is achieved by creating smoke-free spaces in the tunnel through control of the smoke gases. In this paper, results are presented of a study concerning the fire safety in a real scale railway tunnel test case. Numerical simulations are performed in order to examine the possibility of natural ventilation of smoke in inclined tunnels. Several aspects are taken into account: the length of the simulated tunnel section, the slope of the tunnel and the possible effects of external wind at one portal of the tunnel. The Fire Dynamics Simulator of the National Institute of Standards and Technology, USA, is applied to perform the simulations. The simulations show that for the local behavior of the smoke during the early stages of the fire, the slope of the tunnel is of little importance. Secondly, the results show that external wind and/or pressure conditions have a large effect on the smoke gases inside the tunnel. Finally, some idea for the value of the critical ventilation velocity is given. The study also shows that computational fluid dynamics calculations are a valuable tool for large scale, real life complex fire cases. .

Production of oscillatory flow in wind tunnels

Science.gov (United States)

Al-Asmi, K.; Castro, I. P.

1993-06-01

A method for producing oscillatory flow in open-circuit wind tunnels driven by centrifugal fans is described. Performance characteristics of a new device installed on two such tunnels of greatly differing size are presented. It is shown that sinusoidal variations of the working section flow, having peak-to-peak amplitudes up to at least 30 percent of the mean flow speed and frequencies up to, typically, that corresponding to the acoustic quarter-wave-length frequency determined by the tunnel size, can be obtained with negligible harmonic distortion or acoustic noise difficulties. A brief review of the various methods that have been used previously is included, and the advantages and disadvantages of these different techniques are highlighted. The present technique seems to represent a significant improvement over many of them.

Belt drive construction improvement

Directory of Open Access Journals (Sweden)

I.Yu. Khomenko

2012-08-01

Full Text Available The possibility of the traction capacity increase of the belt drive TRK is examined. This was done for the purpose of air conditioning system of passenger car with double-generator system energy supplying. Belts XPC (made by the German firm «Continental ContiTech» testing were conducted. The results confirmed the possibility of their usage in order to improve belt drive TRK characteristics.

The Challenge of Different Perceptions on the Belt and Road Initiative

Directory of Open Access Journals (Sweden)

Junchi Ma

2017-08-01

Full Text Available This article1 focuses on the perceptions of the Chinese and its partners on the Belt and Road Initiative. The author summarizes the existing foreign opinions about the initiative, one “inequality” of the market, three goals that China wants to achieve and two ways in which China wants to create domestic stability. In fact, the difference between foreign and Chinese perceptions is based on the relative national condition of the two sides, the perception of great powers, and the combination of domestic needs and foreign policy. Finally, the author points out that there are three paradoxes which exist in the differences between China and its partners, which is the biggest challenge of the Belt and Road Initiative.

Equilibria and Free Vibration of a Two-Pulley Belt-Driven System with Belt Bending Stiffness

Directory of Open Access Journals (Sweden)

Jieyu Ding

2014-01-01

Full Text Available Nonlinear equilibrium curvatures and free vibration characteristics of a two-pulley belt-driven system with belt bending stiffness and a one-way clutch are investigated. With nonlinear dynamical tension, the transverse vibrations of the translating belt spans and the rotation motions of the pulleys and the accessory shaft are coupled. Therefore, nonlinear piecewise discrete-continuous governing equations are established. Considering the bending stiffness of the translating belt spans, the belt spans are modeled as axially moving beams. The pattern of equilibria is a nontrivial solution. Furthermore, the nontrivial equilibriums of the dynamical system are numerically determined by using two different approaches. The governing equations of the vibration near the equilibrium solutions are derived by introducing a coordinate transform. The natural frequencies of the dynamical systems are studied by using the Galerkin method with various truncations and the differential and integral quadrature methods. Moreover, the convergence of the Galerkin truncation is investigated. Numerical results reveal that the study needs 16 terms after truncation in order to determine the free vibration characteristics of the pulley-belt system with the belt bending stiffness. Furthermore, the first five natural frequencies are very sensitive to the bending stiffness of the translating belt.

Dynamics Analysis and Modeling of Rubber Belt in Large Mine Belt Conveyors

Directory of Open Access Journals (Sweden)

Gao Yang

2014-10-01

Full Text Available Rubber belt not only is one of the key components of belt conveyor, but also affects the overall performance of the core part. Research on dynamics analysis of large conveyor not only helps to improve the reliability and design level, but also can guide the rational selection of conveyor safety factor, and effectively reduce the cost of the conveyor belt. Based on unique viscoelastic properties of belt conveyor, it was simplified as one-dimensional viscoelastic rod in this study, and then a discrete element model of conveyor systems was established. The kinetic equations of each discrete unit was derived using kinetic energy, potential energy of driving segment, bearing segment and return segment and equation of energy dissipation and Lagrange equation. Based on Wilson-q algorithm, the kinetic equation of DT1307-type ST2000's conveyor belt was solved by using Matlab to write computer programs. Research on the change rule of conveyor displacement, velocity, acceleration and dynamic tension during the boot process revealed the working mechanism of nonlinear viscoelastic, which lay the theoretical foundation for dynamic performance optimization of large belt conveyor. The calculation results were used to optimize design and analysis of conveyor system, the result showed that it could reduce the driven tension peaks about 12 %, save 5 % of overall manufacturing cost, which bring considerable profits for enterprises.

Lap belt injuries in children.

LENUS (Irish Health Repository)

McGrath, N

2010-07-01

The use of adult seat belts without booster seats in young children may lead to severe abdominal, lumbar or cervical spine and head and neck injuries. We describe four characteristic cases of lap belt injuries presenting to a tertiary children\\'s hospital over the past year in addition to a review of the current literature. These four cases of spinal cord injury, resulting in significant long-term morbidity in the two survivors and death in one child, arose as a result of lap belt injury. These complex injuries are caused by rapid deceleration characteristic of high impact crashes, resulting in sudden flexion of the upper body around the fixed lap belt, and consequent compression of the abdominal viscera between the lap belt and spine. This report highlights the dangers of using lap belts only without shoulder straps. Age-appropriate child restraint in cars will prevent these injuries.

Belt technology stretches conveyors' coverage

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-15

With China the leading growth engine in the conveyor market, leading belt manufacturers are establishing local manufacturing plants to boost their presence. Fenner is planning to almost triple production capacity over the next three years, with a third of its investment in China. Shanxi-Phoenix Conveyor Belt Systems is a joint venture between Phoenix Conveyor Belt Systems GmbH, now part of ContiTech Ag, and its Chinese partners Lu An Mining Group Co. Ltd. and Jingcheng Anthracite Group Co. Ltd. It manufacturers steel cable belts, PVC and multi-ply belts for coal mines and power plants. Recent belt designs by FennerEurope and Metso Minerals are reported. 2 photos.

Powerful conveyer belt real-time online detection system based on x-ray

Science.gov (United States)

Rong, Feng; Miao, Chang-yun; Meng, Wei

2009-07-01

The powerful conveyer belt is widely used in the mine, dock, and so on. After used for a long time, internal steel rope of the conveyor belt may fracture, rust, joints moving, and so on .This would bring potential safety problems. A kind of detection system based on x-ray is designed in this paper. Linear array detector (LDA) is used. LDA cost is low, response fast; technology mature .Output charge of LDA is transformed into differential voltage signal by amplifier. This kind of signal have great ability of anti-noise, is suitable for long-distance transmission. The processor is FPGA. A IP core control 4-channel A/D convertor, achieve parallel output data collection. Soft-core processor MicroBlaze which process tcp/ip protocol is embedded in FPGA. Sampling data are transferred to a computer via Ethernet. In order to improve the image quality, algorithm of getting rid of noise from the measurement result and taking gain normalization for pixel value is studied and designed. Experiments show that this system work well, can real-time online detect conveyor belt of width of 2.0m and speed of 5 m/s, does not affect the production. Image is clear, visual and can easily judge the situation of conveyor belt.

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-12-15

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

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

International Nuclear Information System (INIS)

Hardenby, Carljohan; Sigurdsson, Oskar

2010-12-01

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

Tunneling technologies for the collider ring tunnels

International Nuclear Information System (INIS)

Frobenius, P.

1989-01-01

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

Quantum tunneling observed without its characteristic large kinetic isotope effects.

Science.gov (United States)

Hama, Tetsuya; Ueta, Hirokazu; Kouchi, Akira; Watanabe, Naoki

2015-06-16

Classical transition-state theory is fundamental to describing chemical kinetics; however, quantum tunneling is also important in explaining the unexpectedly large reaction efficiencies observed in many chemical systems. Tunneling is often indicated by anomalously large kinetic isotope effects (KIEs), because a particle's ability to tunnel decreases significantly with its increasing mass. Here we experimentally demonstrate that cold hydrogen (H) and deuterium (D) atoms can add to solid benzene by tunneling; however, the observed H/D KIE was very small (1-1.5) despite the large intrinsic H/D KIE of tunneling (≳ 100). This strong reduction is due to the chemical kinetics being controlled not by tunneling but by the surface diffusion of the H/D atoms, a process not greatly affected by the isotope type. Because tunneling need not be accompanied by a large KIE in surface and interfacial chemical systems, it might be overlooked in other systems such as aerosols or enzymes. Our results suggest that surface tunneling reactions on interstellar dust may contribute to the deuteration of interstellar aromatic and aliphatic hydrocarbons, which could represent a major source of the deuterium enrichment observed in carbonaceous meteorites and interplanetary dust particles. These findings could improve our understanding of interstellar physicochemical processes, including those during the formation of the solar system.

Drivers' attitudes toward front or rear child passenger belt use and seat belt reminders at these seating positions.

Science.gov (United States)

Kidd, David G; McCartt, Anne T

2014-01-01

Passengers, especially those in rear seating positions, use seat belts less frequently than drivers. In-vehicle technology can inform drivers when their passengers are unbuckled and encourage passengers to use belts. The current study collected information about drivers' attitudes toward passenger belt use and belt reminders for front passengers and children in back seats. A national telephone survey of 1218 people 18 and older was conducted, of which 477 respondents were drivers who transport a front seat passenger at least once a week and 254 were drivers who transport an 8- to 15-year-old child in the back seat. Respondents were asked about their attitudes toward belt use by their front passengers or rear child passengers and preferences for different passenger belt reminder features. Ninety percent of drivers who regularly transport front seat passengers said that the passengers always use seat belts. Reported belt use was even higher among 8- to 15-year-old children in the back seat (97%). Among the drivers whose children do not always buckle up, about half said their child unbuckled the belt during the trip. Almost every full-time belt use driver (96%) would encourage front passengers to buckle up if not belted, compared to 57 percent of part-time belt users and nonusers. In contrast, nearly every driver who transports children in the back seat would encourage their belt use, regardless of the driver's belt use habits. Most drivers who transport front passengers wanted passenger belt reminders to encourage passengers to buckle up. Most of these drivers wanted a chime/buzzer or warning light or text display and wanted the reminder to last indefinitely. Most drivers who transport child passengers in the rear seat wanted the vehicle to indicate whether child passengers are unbuckled. A large majority of these drivers wanted notifications via a visual diagram of seating positions and belt use, a chime/buzzer, and a warning light or text display. These drivers

Some problems of geologic relations between the Amazon craton and east margins fold belts

International Nuclear Information System (INIS)

Almeida, F.F.M. de

1986-01-01

This paper deals with some geologic problems related to the limits between the Amazon craton and the fold belts developed at its margins during the Precambrian. These limits are diversified but clearly recognized. To the north, the Araguaia-Tocantins fold belt, of presumed Middle Proterozoic age, is separated from the cratonic block by a deep marginal fracture zone permeated by mafic and ultramafic rocks. The geologic, magmatic and aeromagnetic characteristics of this zone point out the presence of deep faults, supposed to be of Middle Proterozoic age. The southern Paraguay fold belt constitutes and accurated zone of linear structures supposed to be of Late Proterozoic development. Despite the great increase of knowledge during the last ten years many tectonic, stratigraphic and geochronologic problems remain unsolved. The aim of this paper is to point out some of these problems and suggest specific studies to solve them. (author)

Storm-time electron flux precipitation in the inner radiation belt caused by wave-particle interactions

Directory of Open Access Journals (Sweden)

H. Tadokoro

2009-04-01

Full Text Available It has been believed that electrons in the inner belt do not show the dynamical variation during magnetic storms except for great magnetic storms. However, Tadokoro et al. (2007 recently disclosed that low-altitude electrons in the inner belt frequently show flux variations during storms (Storm Time inner belt Electron Enhancement at the Low altitude (STEEL. This paper investigates a possible mechanism explaining STEEL during small and moderate storms, and shows that it is caused not by radial transport processes but by pitch angle scattering through wave-particle interactions. The waves related to wave-particle interactions are attributed to be banded whistler mode waves around 30 kHz observed in the inner magnetosphere by the Akebono satellite. The estimated pitch angle distribution based on a numerical calculation is roughly consistent with the observed results.

Belt conveyors for bulk materials. 6th ed.

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-07-01

The 16 chapters are entitled: Belt conveyor general applications economics; Design considerations; Characteristics and conveyability of bulk materials; Capacities, belt widths and speeds; Belt conveyor idlers; Belt tension and power engineering; Belt selection; Pulleys and shafts; Curves; Steep angle conveying; Belt cleaners and accessories; Transfer points; Conveyor motor drives and controls; Operation, maintenance and safety; Belt takeups; and Emerging technologies. 6 apps.

Belt conveying of minerals

Energy Technology Data Exchange (ETDEWEB)

Stace, L.R.; Yardley, E.D. [University of Nottingham, Nottingham (United Kingdom). School of Civil Engineering

2008-02-15

A discussion of the history and economics of conveyor applications sets the scene. Conveyor design is investigated in detail, covering power requirements, belt tensioning, and hardware. Principles regarding construction and joining of belts are outlined and a helpful and practical overview of relevant standards, belt test methods, and issues surrounding standardisation is given. Conveyor belt systems can represent a significant operational hazard, so the authors have set out to highlight the important area of safety, with consideration given to fire/electrical resistance, as well as the interface between personnel and conveyor systems - including nip points and operational issues such as man-riding. Selected case studies illustrate some practical aspects of installation and operation, at Selby mine in the UK and Prosper-Haniel Colliery in Germany and others. 3 apps.

High performance vertical tunneling diodes using graphene/hexagonal boron nitride/graphene hetero-structure

Energy Technology Data Exchange (ETDEWEB)

Hwan Lee, Seung; Lee, Jia; Ho Ra, Chang; Liu, Xiaochi; Hwang, Euyheon [Samsung-SKKU Graphene Center (SSGC), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Department of Nano Science and Technology, SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Sup Choi, Min [Department of Nano Science and Technology, SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Center for Human Interface Nano Technology (HINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Hee Choi, Jun [Frontier Research Laboratory, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Yongin, Gyeonggi-do 446-711 (Korea, Republic of); Zhong, Jianqiang; Chen, Wei [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 (Singapore); Jong Yoo, Won, E-mail: yoowj@skku.edu [Samsung-SKKU Graphene Center (SSGC), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Department of Nano Science and Technology, SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Center for Human Interface Nano Technology (HINT), Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

2014-02-03

A tunneling rectifier prepared from vertically stacked two-dimensional (2D) materials composed of chemically doped graphene electrodes and hexagonal boron nitride (h-BN) tunneling barrier was demonstrated. The asymmetric chemical doping to graphene with linear dispersion property induces rectifying behavior effectively, by facilitating Fowler-Nordheim tunneling at high forward biases. It results in excellent diode performances of a hetero-structured graphene/h-BN/graphene tunneling diode, with an asymmetric factor exceeding 1000, a nonlinearity of ∼40, and a peak sensitivity of ∼12 V{sup −1}, which are superior to contending metal-insulator-metal diodes, showing great potential for future flexible and transparent electronic devices.

New directions in scanning-tunneling microscopy

International Nuclear Information System (INIS)

Ferrell, T.L.; Warmack, R.J.; Reddick, R.C.

1989-01-01

The tunneling of electrons in scanning-tunneling microscopy (STM) has permitted imaging of the electronic distribution about individual atoms on surfaces. The need for use of conducting surfaces in STM limits its applicability, and new forms of scanning microscopy have emerged as a result of interest in poorly conducting samples. Atomic force microscopy has demonstrated that the force between a surface and a probe tip can be used to image selected materials. Now being developed are magnetic probe STM's and photon tunneling microscopes in which the probe is a sharpened optical fiber. Also of great interest presently is the measurement of differential conductance of surfaces using electron STM's. This method supplies spectral information and contrast enhancement in images. At present there remains much theoretical work to be carried out in order to better characterize related data on inelastic electron tunneling, and valuable insight may be gained from data being gathered on the local work function of materials. As matters stand today, the key problems lie in determining tip and contamination effects, preparation of samples, and understanding conductivity mechanisms in very thin materials on conducting substrates. Resolution of these problems and introduction of new forms of scanning microscopy may permit novel and important applications in biology as well as surface science

The Fort Smith radioactive belt, Northwest Territories

International Nuclear Information System (INIS)

Charbonneau, B.W.

1980-01-01

The Fort Smith Belt is an elongate zone, about 200 km x 50 km, extending from the East Arm of Great Slave Lake southerly into northeastern Alberta. The major feature of the belt is that it is one of the most radioactive regions so far recognized in the Canadian Shield. Potassium, uranium, and thorium are all enriched but the greatest increase is in thorium. The dominant rock type underlying the area is a foliated porphyritic granite. This rock contains an average of about 80 ppm thorium (with areas of tens of square kilometres containing up to 200 ppm) and approximately 11 ppm uranium. In places, dark elongate zones rich in biotite, apatite, and opaque minerals within the porphyritic granite may contain an order of magnitude more uranium and thorium than the porphyry. Radioactive minerals within both the porphyry and the dark zones are principally monazite (containing up to 16% ThO 2 ) and isolated grains of uraninite. This foliated porphyritic granite is interpreted as being pre- or syntectonic with respect to the Hudsonian event because its foliation parallels that of the surrounding rocks. There has been subsequent deformation. The second characteristic feature of the Fort Smith Belt is the development of a peripheral zone where eU is enriched relative to eTh correlating mainly with granitoid rocks which surround the thorium-rich area and wherein ratios of eU/eTh exceed 1:2 (compared to the crustal average of 1:4). Uranium may have moved laterally into this marginal area from the thorium-rich porphyry, possibly in a vapour phase. There is a possibility that concentrations of uranium as well as other metals such as Cu, Mo, Zn, Sn, and W could exist in the porphyry and its margin in appropriate chemical and/or structural traps. The radioactive granite rocks of the Fort Smith Belt are adjacent to uranium-thorium occurrences in the nearby Proterozoic Nonacho sediments but whether or not a genetic relationship exists between the two situations is uncertain. (auth)

VERO cells harbor a poly-ADP-ribose belt partnering their epithelial adhesion belt

Directory of Open Access Journals (Sweden)

Laura Lafon-Hughes

2014-10-01

Full Text Available Poly-ADP-ribose (PAR is a polymer of up to 400 ADP-ribose units synthesized by poly-ADP-ribose-polymerases (PARPs and degraded by poly-ADP-ribose-glycohydrolase (PARG. Nuclear PAR modulates chromatin compaction, affecting nuclear functions (gene expression, DNA repair. Diverse defined PARP cytoplasmic allocation patterns contrast with the yet still imprecise PAR distribution and still unclear functions. Based on previous evidence from other models, we hypothesized that PAR could be present in epithelial cells where cadherin-based adherens junctions are linked with the actin cytoskeleton (constituting the adhesion belt. In the present work, we have examined through immunofluorescence and confocal microscopy, the subcellular localization of PAR in an epithelial monkey kidney cell line (VERO. PAR was distinguished colocalizing with actin and vinculin in the epithelial belt, a location that has not been previously reported. Actin filaments disruption with cytochalasin D was paralleled by PAR belt disruption. Conversely, PARP inhibitors 3-aminobenzamide, PJ34 or XAV 939, affected PAR belt synthesis, actin distribution, cell shape and adhesion. Extracellular calcium chelation displayed similar effects. Our results demonstrate the existence of PAR in a novel subcellular localization. An initial interpretation of all the available evidence points towards TNKS-1 as the most probable PAR belt architect, although TNKS-2 involvement cannot be discarded. Forthcoming research will test this hypothesis as well as explore the existence of the PAR belt in other epithelial cells and deepen into its functional implications.

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)

2009-07-01

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)

Pelvic belt effects on sacroiliac joint ligaments: a computational approach to understand therapeutic effects of pelvic belts.

Science.gov (United States)

Sichting, Freddy; Rossol, Jerome; Soisson, Odette; Klima, Stefan; Milani, Thomas; Hammer, Niels

2014-01-01

The sacroiliac joint is a widely described source of low back pain. Therapeutic approaches to relieve pain include the application of pelvic belts. However, the effects of pelvic belts on sacroiliac joint ligaments as potential pain generators are mostly unknown. The aim of our study was to analyze the influence of pelvic belts on ligament load by means of a computer model. Experimental computer study using a finite element method. A computer model of the human pelvis was created, comprising bones, ligaments, and cartilage. Detailed geometries, material properties of ligaments, and in-vivo pressure distribution patterns of a pelvic belt were implemented. The effects of pelvic belts on ligament strain were computed in the double-leg stance. Pelvic belts increase sacroiliac joint motion around the sagittal axis but decrease motion around the transverse axis. With pelvic belt application, most of the strained sacroiliac joint ligaments were relieved, especially the sacrospinous, sacrotuberous, and the interosseous sacroiliac ligaments. Sacroiliac joint motion and ligament strains were minute. These results agree with validation data from other studies. Assigning homogenous and linear material properties and excluding muscle forces are clear simplifications of the complex reality. Pelvic belts alter sacroiliac joint motion and provide partial relief of ligament strain that is subjectively marked, although minimal in absolute terms. These findings confirm theories that besides being mechanical stabilizers, the sacroiliac joint ligaments are likely involved in neuromuscular feedback mechanisms. The results from our computer model help with unraveling the therapeutic mechanisms of pelvic belts.

30 CFR 57.4503 - Conveyor belt slippage.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveyor belt slippage. 57.4503 Section 57.4503... Control Installation/construction/maintenance § 57.4503 Conveyor belt slippage. (a) Surface belt conveyors...) Underground belt conveyors shall be equipped with a detection system capable of automatically stopping the...

Investigation of a new type charging belt

International Nuclear Information System (INIS)

Jones, N.L.

1994-01-01

There are many desirable characteristics for an electrostatic accelerator charging belt. An attempt has been made to find a belt that improves on these properties over the stock belt. Results of the search, procurement, and 1,500 hours of operational experience with a substantially different belt are reported

A story about estimation of a random field of boulders from incomplete seismic measurements

DEFF Research Database (Denmark)

Ditlevsen, Ove Dalager

2005-01-01

deposits along the tunnel line. By use of this important distribution information and of the observed homogeneity of the seismic point source field together with the physical properties of diffraction it became possible to make the wanted prediction. During the excavation the found boulders were counted......This paper reports on the statistical interpretation of seismic diffraction measurements of boulder locations. The measurements are made in a corridor along the planned tunnel line for the later realized bored tunnel through the till deposits under the East Channel of the Great Belt in Denmark...... graphical registrations on seismograms do not make a proper interpretation possible without detailed knowledge about the joint distribution of the primary dimensions of the boulders. Therefore separate measurements were made of the dimensions of boulders deposited visibly on the cliff beaches of the Great...

Belt for picking up liquids

Energy Technology Data Exchange (ETDEWEB)

Sewell, R B.H.; Nelson, S P

1973-05-18

This belt for picking up liquids consists of a layer of strong material, e.g., coarse cloth, sewed on at least one layer of absorbing material, e.g., sponge cloth, the stitching being disposed along chevrons with their apexes along the central axis of the belt; the edges do not contain any other marks. This arrangement facilitates the expulsion of the absorbed liquid when the belt passes between compression rollers.

30 CFR 56.4503 - Conveyor belt slippage.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveyor belt slippage. 56.4503 Section 56.4503... Control Installation/construction/maintenance § 56.4503 Conveyor belt slippage. Belt conveyors within... shall attend the belt at the drive pulley when it is necessary to operate the conveyor while temporarily...

14 CFR 27.1413 - Safety belts.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Safety belts. 27.1413 Section 27.1413 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Safety Equipment § 27.1413 Safety belts. Each safety belt...

Persistence of Salmonella on egg conveyor belts is dependent on the belt type but not on the rdar morphotype.

Science.gov (United States)

Stocki, S L; Annett, C B; Sibley, C D; McLaws, M; Checkley, S L; Singh, N; Surette, M G; White, A P

2007-11-01

Commercial caged layer flocks in Alberta, Canada, are commonly monitored for Salmonella enterica serovar Enteritidis (SE) and S. enterica serovar Typhimurium (ST) by environmental sampling. In one recent case, a SE strain isolated from the egg conveyor belt was a source of persistent infection for the flock. This study was undertaken to examine Salmonella colonization on egg conveyor belts and to determine whether the rdar morphotype, a conserved physiology associated with aggregation and long-term survival, contributed to persistence. Four woven belts constructed of natural or nonnatural fibers and a 1-piece belt made of vinyl were tested with rdar-positive ST and SE strains and a rdar-negative ST DeltaagfD reference strain. The type of egg belt was the most important factor influencing Salmonella colonization and persistence. The vinyl belt, with the least surface area available for colonization, had the fewest Salmonella remaining after washing and disinfection, whereas the hemp-plastic belt, with the greatest surface area, had the most Salmonella remaining. Real-time gene expression indicated that the rdar morphotype was involved in colonizing the egg belt pieces; however, it was not essential for persistence. In addition, rdar-positive and rdar-negative strains were equally similarly to disinfection on the egg belt pieces. The results indicate that Salmonella can persist on a variety of egg belts by mechanisms other than the rdar morphotype, and that using egg conveyer belts with reduced surface area for bacterial colonization can lessen contamination problems.

Granulite belts of Central India with special reference to the Bhopalpatnam Granulite Belt: Significance in crustal evolution and implications for Columbia supercontinent

Science.gov (United States)

Vansutre, Sandeep; Hari, K. R.

2010-11-01

The Central Indian collage incorporates the following major granulite belts: (1) the Balaghat-Bhandara Granulite Belt (BBG), (2) the Ramakona-Katangi Granulite Belt (RKG), (3) the Chhatuabhavna Granulite (CBG) of Bilaspur-Raigarh Belt, (4) the Makrohar Granulite Belt (MGB) of Mahakoshal supracrustals, (5) the Kondagaon Granulite Belt (KGGB), (6) the Bhopalpatnam Granulite Belt (BGB), (7) the Konta Granulite Belt (KTGB) and (8) the Karimnagar Granulite Belt (KNGB) of the East Dharwar Craton (EDC). We briefly synthesize the general geologic, petrologic and geochronologic features of these belts and explain the Precambrian crustal evolution in Central India. On the basis of the available data, a collisional relationship between Bastar craton and the EDC during the Paleo-Mesoproterozoic is reiterated as proposed by the earlier workers. The tectonic evolution of only few of the orogenic belts (BGB in particular) of Central India is related to Columbia.

Observed use of automatic seat belts in 1987 cars.

Science.gov (United States)

Williams, A F; Wells, J K; Lund, A K; Teed, N

1989-10-01

Usage of the automatic belt systems supplied by six large-volume automobile manufacturers to meet the federal requirements for automatic restraints were observed in suburban Washington, D.C., Chicago, Los Angeles, and Philadelphia. The different belt systems studied were: Ford and Toyota (motorized, nondetachable automatic shoulder belt), Nissan (motorized, detachable shoulder belt), VW and Chrysler (nonmotorized, detachable shoulder belt), and GM (nonmotorized detachable lap and shoulder belt). Use of automatic belts was significantly greater than manual belt use in otherwise comparable late-model cars for all manufacturers except Chrysler; in Chrysler cars, automatic belt use was significantly lower than manual belt use. The automatic shoulder belts provided by Ford, Nissan, Toyota, and VW increased use rates to about 90%. Because use rates were lower in Ford cars with manual belts, their increase was greater. GM cars had the smallest increase in use rates; however, lap belt use was highest in GM cars. The other manufacturers supply knee bolsters to supplement shoulder belt protection; all--except VW--also provide manual lap belts, which were used by about half of those who used the automatic shoulder belt. The results indicate that some manufacturers have been more successful than others in providing automatic belt systems that result in high use that, in turn, will mean fewer deaths and injuries in those cars.

14 CFR 31.63 - Safety belts.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Safety belts. 31.63 Section 31.63 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.63 Safety belts. (a) There must be a safety belt...

30 CFR 77.1107 - Belt conveyors.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Belt conveyors. 77.1107 Section 77.1107 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY... § 77.1107 Belt conveyors. Belt conveyors in locations where fire would create a hazard to personnel...

46 CFR 169.723 - Safety belts.

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Safety belts. 169.723 Section 169.723 Shipping COAST... Control, Miscellaneous Systems, and Equipment § 169.723 Safety belts. Each vessel must carry a harness type safety belt conforming to Offshore Racing Council (ORC) standards for each person on watch or...

Plant trial of an under-belt capacitance and gamma-ray backscatter gauge for on-belt determination of moisture in coal

International Nuclear Information System (INIS)

Cutmore, N.G.; Rafter, P.T.; Abernethy, D.A.; Millen, M.J.

1989-01-01

A non-contacting under-belt capacitance and gamma-ray backscatter technique has been developed for the on-line measurement of moisture in coal. In this technique, moisture was correlated with radio frequency susceptance and conductance, determined using an under-belt capacitance sensor in which a fringing electric field interrogates a layer of coal on the conveyor belt directly about the sensor. To compensate for variations in the density and thickness of the coal layer, an under-belt gamma-ray backscatter gauge was used to measure an equivalent volume of coal. A plant trial of the technique was conducted at Stockton Borehole Colliery, NSW Australia, where the gauges were installed on the coking coal product conveyor. Product moistures, in the range 7-14%, were determined with r.m.s errors of 0.50 and 0.25 wt% using on-belt and static off-belt gauges, respectively. The difference in the on-belt and off-belt gauge measurement accuracy was attributed to sampling errors in the calibration of the on-belt gauge. 6 refs., 6 figs., 3 tabs

Precipitation of relativistic electrons of the Van Allen belts into the proton aurora

International Nuclear Information System (INIS)

Jordanova, Vania K.; Miyoshi, Y.; Sakaguchi, K.; Shiokawa, K.; Evans, D.S.; Albert, Jay; Connors, M

2008-01-01

The Van Allen electron belts consist of two regions encircling the earth in which relativistic electrons are trapped in the earth's magnetic field. Populations of relativistic electrons in the Van Allen belts vary greatly with geomagnetic disturbance and they are a major source of damage to space vehicles. In order to know when and by how much these populations of relativistic electrons increase, it is important to elucidate not only the cause of acceleration of relativistic electrons but also the cause of their loss from the Van Allen belts. Here we show the first evidence that left-hand polarized electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere, on the basis of results of an excellent set of ground and satellite observations showing coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The proton aurora was produced by precipitation of ions with energies of tens of keV due to EMIC waves near the plasma pause, which is a manifestation of wave-particle interactions. These observations clarify that ions with energies of tens of keV affect the evolution of relativistic electrons in the Van Allen belts via parasitic resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's

Heat flow and heat generation in greenstone belts

Science.gov (United States)

Drury, M. J.

1986-01-01

Heat flow has been measured in Precambrian shields in both greenstone belts and crystalline terrains. Values are generally low, reflecting the great age and tectonic stability of the shields; they range typically between 30 and 50 mW/sq m, although extreme values of 18 and 79 mW/sq m have been reported. For large areas of the Earth's surface that are assumed to have been subjected to a common thermotectonic event, plots of heat flow against heat generation appear to be linear, although there may be considerable scatter in the data. The relationship is expressed as: Q = Q sub o + D A sub o in which Q is the observed heat flow, A sub o is the measured heat generation at the surface, Q sub o is the reduced heat flow from the lower crust and mantle, and D, which has the dimension of length, represents a scale depth for the distribution of radiogenic elements. Most authors have not used data from greenstone belts in attempting to define the relationship within shields, considering them unrepresentative and preferring to use data from relatively homogeneous crystalline rocks. A discussion follows.

36 CFR 4.15 - Safety belts.

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Safety belts. 4.15 Section 4... TRAFFIC SAFETY § 4.15 Safety belts. (a) Each operator and passenger occupying any seating position of a motor vehicle in a park area will have the safety belt or child restraint system properly fastened at...

Cryogenic Wind Tunnel Models. Design and Fabrication

Science.gov (United States)

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

1983-01-01

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

Many-body Tunneling and Nonequilibrium Dynamics of Doublons in Strongly Correlated Quantum Dots.

Science.gov (United States)

Hou, WenJie; Wang, YuanDong; Wei, JianHua; Zhu, ZhenGang; Yan, YiJing

2017-05-30

Quantum tunneling dominates coherent transport at low temperatures in many systems of great interest. In this work we report a many-body tunneling (MBT), by nonperturbatively solving the Anderson multi-impurity model, and identify it a fundamental tunneling process on top of the well-acknowledged sequential tunneling and cotunneling. We show that the MBT involves the dynamics of doublons in strongly correlated systems. Proportional to the numbers of dynamical doublons, the MBT can dominate the off-resonant transport in the strongly correlated regime. A T 3/2 -dependence of the MBT current on temperature is uncovered and can be identified as a fingerprint of the MBT in experiments. We also prove that the MBT can support the coherent long-range tunneling of doublons, which is well consistent with recent experiments on ultracold atoms. As a fundamental physical process, the MBT is expected to play important roles in general quantum systems.

Tunnel - history of

International Nuclear Information System (INIS)

1998-11-01

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

Drive alive: teen seat belt survey program.

Science.gov (United States)

Burkett, Katie M; Davidson, Steve; Cotton, Carol; Barlament, James; Loftin, Laurel; Stephens, James; Dunbar, Martin; Butterfield, Ryan

2010-08-01

To increase teen seat belt use among drivers at a rural high school by implementing the Drive Alive Pilot Program (DAPP), a theory-driven intervention built on highway safety best practices. The first component of the program was 20 observational teen seat belt surveys conducted by volunteer students in a high school parking lot over a 38-month period before and after the month-long intervention. The survey results were published in the newspaper. The second component was the use of incentives, such as gift cards, to promote teen seat belt use. The third component involved disincentives, such as increased police patrol and school policies. The fourth component was a programmatic intervention that focused on education and media coverage of the DAPP program. Eleven pre-intervention surveys and nine post-intervention surveys were conducted before and after the intervention. The pre- and post-intervention seat belt usage showed significant differences (p<0.0001). The average pre-intervention seat belt usage rate was 51.2%, while the average post-intervention rate was 74.5%. This represents a percentage point increase of 23.3 in seat belt use after the DAPP intervention. Based on seat belt observational surveys, the DAPP was effective in increasing seat belt use among rural high school teenagers. Utilizing a theory-based program that builds on existing best practices can increase the observed seat belt usage among rural high school students.

Children's and Adults' Comfort Experience of Extra Seat Belts When Riding in the Rear Seat of a Passenger Car.

Science.gov (United States)

Osvalder, Anna-Lisa; Hansson, Ida; Bohman, Katarina

2015-01-01

The objective of this study was to explore passengers' comfort experience of extra seat belts during on-road driving in the rear seat of a passenger car and to investigate how the use of extra belts affects children's and adults' attitudes to the product. Two different seat belt systems were tested, criss-cross (CC) and backpack (BP), consisting of the standard 3-point belt together with an additional 2-point belt. In total, 32 participants (15 children aged 6-10, 6 youths aged 11-15, and 11 adults aged 20-79, who differed considerably in size, shape, and proportions) traveled for one hour with each system, including city traffic and highway driving. Four video cameras monitored the test subject during the drive. Subjective data regarding emotions and perceived discomfort were collected in questionnaires every 20 min. A semistructured interview was held afterwards. All participant groups accepted the new products and especially the increased feeling of safety (P car. CC was appreciated for its symmetry, comfort, and the perceived feeling of safety. Some participants found CC unpleasant because the belts tended to slip close to the neck, described as a strangling feeling. BP was simpler to use and did not cause annoyance to the neck in the way CC did. Instead, it felt asymmetric and to some extent less safe than CC. Body size and shape affected seat belt fit to a great extent, which in turn affected the experience of comfort, both initially and over time. Perceived safety benefit and experienced comfort were the most determinant factors for the attitude toward the extra seat belts. The extra seat belts were perceived as being better than the participants had expected before the test, and they became more used to them over time. This exploratory study provided valuable knowledge from a user perspective for further development of new seat belt systems in cars. In addition to an increased feeling of safety, seat belt fit and comfort are supplementary influencing

Chaos on the conveyor belt.

Science.gov (United States)

Sándor, Bulcsú; Járai-Szabó, Ferenc; Tél, Tamás; Néda, Zoltán

2013-04-01

The dynamics of a spring-block train placed on a moving conveyor belt is investigated both by simple experiments and computer simulations. The first block is connected by a spring to an external static point and, due to the dragging effect of the belt, the blocks undergo complex stick-slip dynamics. A qualitative agreement with the experimental results can be achieved only by taking into account the spatial inhomogeneity of the friction force on the belt's surface, modeled as noise. As a function of the velocity of the conveyor belt and the noise strength, the system exhibits complex, self-organized critical, sometimes chaotic, dynamics and phase transition-like behavior. Noise-induced chaos and intermittency is also observed. Simulations suggest that the maximum complexity of the dynamical states is achieved for a relatively small number of blocks (around five).

Physical properties and analytical models of band-to-band tunneling in low-bandgap semiconductors

International Nuclear Information System (INIS)

Shih, Chun-Hsing; Dang Chien, Nguyen

2014-01-01

Low-bandgap semiconductors, such as InAs and InSb, are widely considered to be ideal for use in tunnel field-effect transistors to ensure sufficient on-current boosting at low voltages. This work elucidates the physical and mathematical considerations of applying conventional band-to-band tunneling models in low-bandgap semiconductors, and presents a new analytical alternative for practical use. The high-bandgap tunneling generates most at maximum field region with shortest tunnel path, whereas the low-bandgap generations occur dispersedly because of narrow tunnel barrier. The local electrical field associated with tunneling-electron numbers dominates in low-bandgap materials. This work proposes decoupled electric-field terms in the pre-exponential factor and exponential function of generation-rate expressions. Without fitting, the analytical results and approximated forms exhibit great agreements with the sophisticated forms both in high- and low-bandgap semiconductors. Neither nonlocal nor local field is appropriate to be used in numerical simulations for predicting the tunneling generations in a variety of low- and high-bandgap semiconductors

Quantum Tunneling in Breather Nano-colliders

OpenAIRE

Dubinko, V. I.

2015-01-01

In many crystals with sufficient anharmonicity, a special kind of lattice vibrations, namely, discrete breathers (DBs) can be excited either thermally or by external triggering, in which the amplitude of atomic oscillations greatly exceeds that of harmonic oscillations (phonons). Coherency and persistence of large atomic oscillations in DBs may have drastic effect on quantum tunneling due to correlation effects discovered by Schrodinger and Robertson in 1930. These effects have been applied r...

Multidisciplinary design optimization of the belt drive system considering both structure and vibration characteristics based on improved genetic algorithm

Science.gov (United States)

Yuan, Yongliang; Song, Xueguan; Sun, Wei; Wang, Xiaobang

2018-05-01

The dynamic performance of a belt drive system is composed of many factors, such as the efficiency, the vibration, and the optimal parameters. The conventional design only considers the basic performance of the belt drive system, while ignoring its overall performance. To address all these challenges, the study on vibration characteristics and optimization strategies could be a feasible way. This paper proposes a new optimization strategy and takes a belt drive design optimization as a case study based on the multidisciplinary design optimization (MDO). The MDO of the belt drive system is established and the corresponding sub-systems are analyzed. The multidisciplinary optimization is performed by using an improved genetic algorithm. Based on the optimal results obtained from the MDO, the three-dimension (3D) model of the belt drive system is established for dynamics simulation by virtual prototyping. From the comparison of the results with respect to different velocities and loads, the MDO method can effectively reduce the transverse vibration amplitude. The law of the vibration displacement, the vibration frequency, and the influence of velocities on the transverse vibrations has been obtained. Results show that the MDO method is of great help to obtain the optimal structural parameters. Furthermore, the kinematics principle of the belt drive has been obtained. The belt drive design case indicates that the proposed method in this paper can also be used to solve other engineering optimization problems efficiently.

30 CFR 75.1403-5 - Criteria-Belt conveyors.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Criteria-Belt conveyors. 75.1403-5 Section 75... Criteria—Belt conveyors. (a) Positive-acting stop controls should be installed along all belt conveyors... can be stopped or started at any location. (b) Belt conveyors used for regularly scheduled mantrips...

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

International Nuclear Information System (INIS)

Halbritter, J.

1997-01-01

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

Drive Alive: Teen Seat Belt Survey Program

Directory of Open Access Journals (Sweden)

Loftin, Laurel

2010-08-01

Full Text Available Objective: To increase teen seat belt use among drivers at a rural high school by implementing the Drive Alive Pilot Program (DAPP, a theory-driven intervention built on highway safety best practices.Methods: The first component of the program was 20 observational teen seat belt surveys conducted by volunteer students in a high school parking lot over a 38-month period before and after the month-long intervention. The survey results were published in the newspaper. The second component was the use of incentives, such as gift cards, to promote teen seat belt use. The third component involved disincentives, such as increased police patrol and school policies. The fourth component was a programmatic intervention that focused on education and media coverage of the DAPP program.Results: Eleven pre-intervention surveys and nine post-intervention surveys were conducted before and after the intervention. The pre- and post-intervention seat belt usage showed significant differences (p<0.0001. The average pre-intervention seat belt usage rate was 51.2%, while the average post-intervention rate was 74.5%. This represents a percentage point increase of 23.3 in seat belt use after the DAPP intervention.Conclusion: Based on seat belt observational surveys, the DAPP was effective in increasing seat belt use among rural high school teenagers. Utilizing a theory-based program that builds on existing best practices can increase the observed seat belt usage among rural high school students. [West J Emerg Med. 2010; 11(3: 280-283.

Synchronous and Cogged Fan Belt Performance Assessment

Energy Technology Data Exchange (ETDEWEB)

Cutler, Dylan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dean, Jesse [National Renewable Energy Lab. (NREL), Golden, CO (United States); Acosta, Jason [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2014-02-01

The GSA Regional GPG Team commissioned the National Renewable Energy Laboratory (NREL) to perform monitoring of cogged V-belts and synchronous belts on both a constant volume and a variable air volume fan at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. These motor/fan combinations were tested with their original, standard V-belts (appropriately tensioned by an operation and maintenance professional) to obtain a baseline for standard operation. They were then switched to the cogged V-belts, and finally to synchronous belts. The power consumption by the motor was normalized for both fan speed and air density changes. This was necessary to ensure that the power readings were not influenced by a change in rotational fan speed or by the power required to push denser air. Finally, energy savings and operation and maintenance savings were compiled into an economic life-cycle cost analysis of the different belt options.

AUTOMATION OF CONVEYOR BELT TRANSPORT

Directory of Open Access Journals (Sweden)

Nenad Marinović

1990-12-01

Full Text Available Belt conveyor transport, although one of the most economical mining transport system, introduce many problems to mantain the continuity of the operation. Every stop causes economical loses. Optimal operation require correct tension of the belt, correct belt position and velocity and faultless rolls, which are together input conditions for automation. Detection and position selection of the faults are essential for safety to eliminate fire hazard and for efficient maintenance. Detection and location of idler roll faults are still open problem and up to now not solved successfully (the paper is published in Croatian.

Large-scale fabrication of BN tunnel barriers for graphene spintronics

International Nuclear Information System (INIS)

Fu, Wangyang; Makk, Péter; Maurand, Romain; Bräuninger, Matthias; Schönenberger, Christian

2014-01-01

We have fabricated graphene spin-valve devices utilizing scalable materials made from chemical vapor deposition (CVD). Both the spin-transporting graphene and the tunnel barrier material are CVD-grown. The tunnel barrier is realized by Hexagonal boron nitride, used either as a monolayer or bilayer and placed over the graphene. Spin transport experiments were performed using ferromagnetic contacts deposited onto the barrier. We find that spin injection is still greatly suppressed in devices with a monolayer tunneling barrier due to resistance mismatch. This is, however, not the case for devices with bilayer barriers. For those devices, a spin relaxation time of ∼260 ps intrinsic to the CVD graphene material is deduced. This time scale is comparable to those reported for exfoliated graphene, suggesting that this CVD approach is promising for spintronic applications which require scalable materials

Feed chute geometry for minimum belt wear

Energy Technology Data Exchange (ETDEWEB)

Roberts, A W; Wiche, S J [University of Newcastle, Newcastle, NSW (Australia). Centre for Bulk Solids and Particulate Technologies

1998-09-01

The paper is concerned with the feeding and transfer of bulk solids in conveyor belt operation. The paper focuses on chute design where the objective is to prevent spillage and minimise both chute and belt wear. It is shown that these objectives may be met through correct dynamic design of the chute and by directing the flow of bulk solids onto the belt at an acceptable incidence angle. The aim is to match the tangential velocity component of the feed velocity as close as possible to the belt velocity. At the same time, it is necessary to limit the impact pressure due to the change in momentum of the bulk solid as it feeds onto the belt. 2 refs., 8 figs.

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 Document Server

1983-01-01

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...

Mechanism of water inrush in tunnel construction in karst area

Directory of Open Access Journals (Sweden)

Liping Li

2016-05-01

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

Determination of relative immobile and sliding areas between carrying and tractive belts in using of belt conveyor intermediate drives

OpenAIRE

Goncharov K.A.

2015-01-01

Method of determination of relative immobile and sliding areas between carrying and tractive belts in places of mount-ing of belt conveyor intermediate drives made in the form of tractive contours is proposed. The example shows potential of this method in multidrive belt conveyor design process.

30 CFR 75.1108 - Approved conveyor belts.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Approved conveyor belts. 75.1108 Section 75... Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1108 Approved conveyor belts. (a) Until December 31, 2009 conveyor belts placed in service in underground coal mines shall be: (1) Approved under...

Macroscopic quantum tunneling of a Bose-Einstein condensate through double Gaussian barriers

Science.gov (United States)

Maeda, Kenji; Urban, Gregor; Weidemüller, Matthias; Carr, Lincoln D.

2015-05-01

Macroscopic quantum tunneling is one of the great manifestations of quantum physics, not only showing passage through a potential barrier but also emerging in a many-body wave function. We study a quasi-1D Bose-Einstein condensate of Lithium, confined by two Gaussian barriers, and show that in an experimentally realistic potential tens of thousands of atoms tunnel on time scales of 10 to 100 ms. Using a combination of variational and WKB approximations based on the Gross-Pitaevskii or nonlinear Schrödinger equation, we show that many unusual tunneling features appear due to the nonlinearity, including the number of trapped atoms exhibiting non-exponential decay, severe distortion of the barriers by the mean field, and even formation of a triple barrier in certain regimes. In the first 10ms, nonlinear many-body effects make the tunneling rates significantly larger than background loss rates, from 10 to 70 Hz. Thus we conclude that macroscopic quantum tunneling can be observed on experimental time scales. Funded by NSF, AFOSR, the Alexander von Humboldt foundation, and the Heidelberg Center for Quantum Dynamics.

Electronic-Reconstruction-Enhanced Tunneling Conductance at Terrace Edges of Ultrathin Oxide Films.

Science.gov (United States)

Wang, Lingfei; Kim, Rokyeon; Kim, Yoonkoo; Kim, Choong H; Hwang, Sangwoon; Cho, Myung Rae; Shin, Yeong Jae; Das, Saikat; Kim, Jeong Rae; Kalinin, Sergei V; Kim, Miyoung; Yang, Sang Mo; Noh, Tae Won

2017-11-01

Quantum mechanical tunneling of electrons across ultrathin insulating oxide barriers has been studied extensively for decades due to its great potential in electronic-device applications. In the few-nanometers-thick epitaxial oxide films, atomic-scale structural imperfections, such as the ubiquitously existed one-unit-cell-high terrace edges, can dramatically affect the tunneling probability and device performance. However, the underlying physics has not been investigated adequately. Here, taking ultrathin BaTiO 3 films as a model system, an intrinsic tunneling-conductance enhancement is reported near the terrace edges. Scanning-probe-microscopy results demonstrate the existence of highly conductive regions (tens of nanometers wide) near the terrace edges. First-principles calculations suggest that the terrace-edge geometry can trigger an electronic reconstruction, which reduces the effective tunneling barrier width locally. Furthermore, such tunneling-conductance enhancement can be discovered in other transition metal oxides and controlled by surface-termination engineering. The controllable electronic reconstruction can facilitate the implementation of oxide electronic devices and discovery of exotic low-dimensional quantum phases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effectiveness of media and enforcement campaigns in increasing seat belt usage rates in a state with a secondary seat belt law.

Science.gov (United States)

Vasudevan, Vinod; Nambisan, Shashi S; Singh, Ashok K; Pearl, Traci

2009-08-01

In 2005, in terms of seat belt usage rates, Nevada ranked third nationally and first among states with secondary seat belt use enforcement laws in the United States. An effective combination of a media-based education and enforcement campaign helped in this regard. The objective of this article is to document the effectiveness of enforcement and media-based education and outreach campaigns on the seat belt usage rates in Nevada, a state with a secondary seat belt usage law. Observational data on seat belt usage and passenger fatality data are used to evaluate the effectiveness of enforcement campaigns and media-based education and outreach campaigns. Data based on observations of about 40,000 vehicles in each of the years 2003 to 2005 were analyzed. Statistical analyses show that a significant increase in seat belt usage rates among both drivers and passengers for both genders resulted from the accompanying the media and enforcement campaigns. The results from this study indicate that effective and well-planned media/enforcement campaigns can have a significant impact on seat belt usage rates even in a state where the enforcement of seat belt laws can only be as a secondary violation. They validate and expand on findings from other efforts documented in the literature. These results demonstrate that, if coordinated properly, media and enforcement campaigns work very effectively in increasing seat belt usage rates even in states with secondary seat belt laws.

Determination of relative immobile and sliding areas between carrying and tractive belts in using of belt conveyor intermediate drives

Directory of Open Access Journals (Sweden)

Goncharov K.A.

2015-12-01

Full Text Available Method of determination of relative immobile and sliding areas between carrying and tractive belts in places of mount-ing of belt conveyor intermediate drives made in the form of tractive contours is proposed. The example shows potential of this method in multidrive belt conveyor design process.

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

NARCIS (Netherlands)

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

1999-01-01

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

Method of monitoring, inspecting or testing conveyor belts

International Nuclear Information System (INIS)

Van der Walt, A.J.

1985-01-01

An invention is discussed which provides a method, installation and kit for monitoring, inspecting or testing a conveyor belt. Provision is made to transmit penetrating rays such as X-rays through a moving conveyor belt, forming a visible moving image from rays transmitted through the belt, and visually inspecting such moving image, after recording it if desired, to ascertain the condition of the interior of the belt. Typically an X-ray tube head is used to transmit the rays through the belt to a fluorescent screen which forms the image. The moving image can be recorded by means of a video camera

Particle-scale Analysis of Key Technologies on Cut-and-over Tunnel in Slope Engineering

Directory of Open Access Journals (Sweden)

J.H. Yang

2014-08-01

Full Text Available When the shallow tunnel is constructed on the slope terrain in the mountains, there are the potential risks such as landslide induced by cutting the slope and the non-compacted backfill material during the construction of the cut-andcover tunnel. In order to solve these problems, based on a practical engineering, the optimized construction plans of the cut-and-cover tunnel were analyzed by particle flow code (PFC, the key parts of the open-cut construction were identified, and the anti-slide piles countermeasures were proposed. Furthermore, the grouting reinforcement process for the non-compacted backfill material around the shallow tunnel was simulated by PFC, and the variation characteristics of the porosity and grouting pressure were revealed as well. The results are of great value to the similar engineering.

The development of an electronic system to continually monitor, indicate and control, 'belt slippage' in industrial friction 'V' belt drive transmission systems

International Nuclear Information System (INIS)

Brown, R E

2012-01-01

Belts have been used for centuries as a mechanism to transfer power from some form of drive system to a variety of load systems. Within industry today, many designs of belts but particularly friction, trapezoidal shaped 'V' belts are used and generally transfer power generated by electrical motors to numerous forms of driven load systems. It is suggested that belt systems, through their simplicity are sadly neglected by maintenance functions and generally are left unattended until high degrees of 'belt slippage' through loss of friction or 'belt breakage' provokes maintenance attention. These circumstances are most often identified through the reduced or loss of manufacturing production or the occurrence of catastrophic circumstances such as fire caused through excessive friction/ high belt slippage conditions. Obviously, these situations incur financial losses to companies and in some cases the near loss of the company's main manufacturing plant. Consequently, a satisfactory, viable solution is currently sought by industry to improve on current labour intensive maintenance practices. This paper will present an account of the development of an industrially robust, accurate and repeatable electronic system which continually monitors and indicates the degree of 'slippage' in a 'V' belt drive transmission system and in the circumstance of belt breakage or high belt slippage will enable and control the switching off the drive motor.

Grinding Glass Disks On A Belt Sander

Science.gov (United States)

Lyons, James J., III

1995-01-01

Small machine attached to table-top belt sander makes possible to use belt sander to grind glass disk quickly to specified diameter within tolerance of about plus or minus 0.002 in. Intended to be used in place of production-shop glass grinder. Held on driveshaft by vacuum, glass disk rotated while periphery ground by continuous sanding belt.

The influence of environmental variability on the biogeography of coccolithophores and diatoms in the Great Calcite Belt

Science.gov (United States)

Smith, Helen E. K.; Poulton, Alex J.; Garley, Rebecca; Hopkins, Jason; Lubelczyk, Laura C.; Drapeau, Dave T.; Rauschenberg, Sara; Twining, Ben S.; Bates, Nicholas R.; Balch, William M.

2017-11-01

The Great Calcite Belt (GCB) of the Southern Ocean is a region of elevated summertime upper ocean calcite concentration derived from coccolithophores, despite the region being known for its diatom predominance. The overlap of two major phytoplankton groups, coccolithophores and diatoms, in the dynamic frontal systems characteristic of this region provides an ideal setting to study environmental influences on the distribution of different species within these taxonomic groups. Samples for phytoplankton enumeration were collected from the upper mixed layer (30 m) during two cruises, the first to the South Atlantic sector (January-February 2011; 60° W-15° E and 36-60° S) and the second in the South Indian sector (February-March 2012; 40-120° E and 36-60° S). The species composition of coccolithophores and diatoms was examined using scanning electron microscopy at 27 stations across the Subtropical, Polar, and Subantarctic fronts. The influence of environmental parameters, such as sea surface temperature (SST), salinity, carbonate chemistry (pH, partial pressure of CO2 (pCO2), alkalinity, dissolved inorganic carbon), macronutrients (nitrate + nitrite, phosphate, silicic acid, ammonia), and mixed layer average irradiance, on species composition across the GCB was assessed statistically. Nanophytoplankton (cells 2-20 µm) were the numerically abundant size group of biomineralizing phytoplankton across the GCB, with the coccolithophore Emiliania huxleyi and diatoms Fragilariopsis nana, F. pseudonana, and Pseudo-nitzschia spp. as the most numerically dominant and widely distributed. A combination of SST, macronutrient concentrations, and pCO2 provided the best statistical descriptors of the biogeographic variability in biomineralizing species composition between stations. Emiliania huxleyi occurred in silicic acid-depleted waters between the Subantarctic Front and the Polar Front, a favorable environment for this species after spring diatom blooms remove silicic acid

Colors of Inner Disk Classical Kuiper Belt Objects

Science.gov (United States)

Romanishin, W.; Tegler, S. C.; Consolmagno, G. J.

2010-07-01

We present new optical broadband colors, obtained with the Keck 1 and Vatican Advanced Technology telescopes, for six objects in the inner classical Kuiper Belt. Objects in the inner classical Kuiper Belt are of interest as they may represent the surviving members of the primordial Kuiper Belt that formed interior to the current position of the 3:2 resonance with Neptune, the current position of the plutinos, or, alternatively, they may be objects formed at a different heliocentric distance that were then moved to their present locations. The six new colors, combined with four previously published, show that the ten inner belt objects with known colors form a neutral clump and a reddish clump in B-R color. Nonparametric statistical tests show no significant difference between the B-R color distribution of the inner disk objects compared to the color distributions of Centaurs, plutinos, or scattered disk objects. However, the B-R color distribution of the inner classical Kuiper Belt Objects does differ significantly from the distribution of colors in the cold (low inclination) main classical Kuiper Belt. The cold main classical objects are predominately red, while the inner classical belt objects are a mixture of neutral and red. The color difference may reveal the existence of a gradient in the composition and/or surface processing history in the primordial Kuiper Belt, or indicate that the inner disk objects are not dynamically analogous to the cold main classical belt objects.

COLORS OF INNER DISK CLASSICAL KUIPER BELT OBJECTS

International Nuclear Information System (INIS)

Romanishin, W.; Tegler, S. C.; Consolmagno, G. J.

2010-01-01

We present new optical broadband colors, obtained with the Keck 1 and Vatican Advanced Technology telescopes, for six objects in the inner classical Kuiper Belt. Objects in the inner classical Kuiper Belt are of interest as they may represent the surviving members of the primordial Kuiper Belt that formed interior to the current position of the 3:2 resonance with Neptune, the current position of the plutinos, or, alternatively, they may be objects formed at a different heliocentric distance that were then moved to their present locations. The six new colors, combined with four previously published, show that the ten inner belt objects with known colors form a neutral clump and a reddish clump in B-R color. Nonparametric statistical tests show no significant difference between the B-R color distribution of the inner disk objects compared to the color distributions of Centaurs, plutinos, or scattered disk objects. However, the B-R color distribution of the inner classical Kuiper Belt Objects does differ significantly from the distribution of colors in the cold (low inclination) main classical Kuiper Belt. The cold main classical objects are predominately red, while the inner classical belt objects are a mixture of neutral and red. The color difference may reveal the existence of a gradient in the composition and/or surface processing history in the primordial Kuiper Belt, or indicate that the inner disk objects are not dynamically analogous to the cold main classical belt objects.

Speed Controlled Belt Conveyors: Drives and Mechanical Considerations

Directory of Open Access Journals (Sweden)

BEBIC, M. Z.

2018-02-01

Full Text Available The paper presents variable speed belt conveyor system where the reference speed is changed in order to achieve improved energy efficiency of operation. The recorded measurements show that belt tension varies within the same limits as under constant speed operation. These results introduce a new insight of the present state of the art in variable speed belt conveyor drives. The system is realized with remote control from the control center on an open pit mine. The structure of the multi-motor drive system of a single conveyor, as well as of the network-based control system distributed among belt conveyor stations and the control center are shown. Speed control of a belt conveyor system is organized to provide better utilization of the available material cross section on the belt and reduced electrical energy consumption of the drive. The experimental results obtained on the system prove that, under existing constraints, the applied algorithm has not introduced additional stress to the belt or mechanical assemblies during acceleration and deceleration processes, while providing higher energy efficiency of operation.

Timing belt in power transmission and conveying system

Directory of Open Access Journals (Sweden)

Domek Grzegorz

2018-01-01

Full Text Available This paper presents the problem of phenomena occurring at the contact of a timing belt and a pulley. Depending on a belt size range these phenomena differ significantly. There is no indication as to what solutions are optimal for drive belts. The analysis of the coupling process and performance tests have shown that the drive belt should have a cord of very good mechanical properties and its raceway side should be made from the material of a low friction coefficient against the pulley material. A flat belt in power transmission and conveying systems cooperates with several elements consisting of timing pulleys, tensioners or guiding rails. In gear with timing belts they depend strongly on characteristics of the process as well as the type of friction. In recent constructions, producers of timing belts are very much concerned about achieving as much slippery surface as possible. The work describes the problem of friction on different surfaces as well as its influence on gear lifetime. Research results confirm that on many surfaces bigger coefficient of friction is expected.

Optimal tunneling enhances the quantum photovoltaic effect in double quantum dots

International Nuclear Information System (INIS)

Wang, Chen; Cao, Jianshu; Ren, Jie

2014-01-01

We investigate the quantum photovoltaic effect in double quantum dots by applying the nonequilibrium quantum master equation. A drastic suppression of the photovoltaic current is observed near the open circuit voltage, which leads to a large filling factor. We find that there always exists an optimal inter-dot tunneling that significantly enhances the photovoltaic current. Maximal output power will also be obtained around the optimal inter-dot tunneling. Moreover, the open circuit voltage behaves approximately as the product of the eigen-level gap and the Carnot efficiency. These results suggest a great potential for double quantum dots as efficient photovoltaic devices

Tunnel magnetoresistance in asymmetric double-barrier magnetic tunnel junctions

International Nuclear Information System (INIS)

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

2015-01-01

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

Conveyor belt weigher using a nuclear technique

International Nuclear Information System (INIS)

Magal, B.S.

1976-01-01

Principles of operation of different types of continuous conveyor belt weighing machines developed for use in factories for bulk weighing of material on conveyor belts without interupting the material flow, are briefly mentioned. The design of nuclear weighing scale making use of the radiation absorption property of the material used is described in detail. The radiation source, choice of the source, detector and geometry of such a weighing scale are discussed. The nucleonic belt weigher is compared with the gravimetric belt weigher system. The advantages of the nuclear system are pointed out. The assembly drawing of the electronics, calibration procedure and performance evaluation are given. (A.K.)

HERSCHEL -RESOLVED OUTER BELTS OF TWO-BELT DEBRIS DISKS—EVIDENCE OF ICY GRAINS

Energy Technology Data Exchange (ETDEWEB)

Morales, F. Y.; Bryden, G.; Werner, M. W.; Stapelfeldt, K. R., E-mail: Farisa@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

2016-11-01

We present dual-band Herschel /PACS imaging for 59 main-sequence stars with known warm dust ( T {sub warm} ∼ 200 K), characterized by Spitzer . Of 57 debris disks detected at Herschel wavelengths (70 and/or 100 and 160 μ m), about half have spectral energy distributions (SEDs) that suggest two-ring disk architectures mirroring that of the asteroid–Kuiper Belt geometry; the rest are consistent with single belts of warm, asteroidal material. Herschel observations spatially resolve the outer/cold dust component around 14 A-type and 4 solar-type stars with two-belt systems, 15 of which for the first time. Resolved disks are typically observed with radii >100 AU, larger than expected from a simple blackbody fit. Despite the absence of narrow spectral features for ice, we find that the shape of the continuum, combined with resolved outer/cold dust locations, can help constrain the grain size distribution and hint at the dust’s composition for each resolved system. Based on the combined Spitzer /IRS+Multiband Imaging Photometer (5-to-70 μ m) and Herschel /PACS (70-to-160 μ m) data set, and under the assumption of idealized spherical grains, we find that over half of resolved outer/cold belts are best fit with a mixed ice/rock composition. Minimum grain sizes are most often equal to the expected radiative blowout limit, regardless of composition. Three of four resolved systems around the solar-type stars, however, tend to have larger minimum grains compared to expectation from blowout ( f {sub MB} = a {sub min}/ a {sub BOS} ∼ 5). We also probe the disk architecture of 39 Herschel -unresolved systems by modeling their SEDs uniformly, and find them to be consistent with 31 single- and 8 two-belt debris systems.

Compliance with Seat Belt Use in Makurdi, Nigeria: An ...

African Journals Online (AJOL)

Background: Seat belts are designed to reduce injuries due to road crash among vehicle occupants. Aims: This study aims to determine the availability of seat belt in vehicles and compliance with seat belt use among vehicle occupants. Materials and methods: This was a 24‑h direct observational study of seat belt usage ...

Encoding, training and retrieval in ferroelectric tunnel junctions

Science.gov (United States)

Xu, Hanni; Xia, Yidong; Xu, Bo; Yin, Jiang; Yuan, Guoliang; Liu, Zhiguo

2016-05-01

Ferroelectric tunnel junctions (FTJs) are quantum nanostructures that have great potential in the hardware basis for future neuromorphic applications. Among recently proposed possibilities, the artificial cognition has high hopes, where encoding, training, memory solidification and retrieval constitute a whole chain that is inseparable. However, it is yet envisioned but experimentally unconfirmed. The poor retention or short-term store of tunneling electroresistance, in particular the intermediate states, is still a key challenge in FTJs. Here we report the encoding, training and retrieval in BaTiO3 FTJs, emulating the key features of information processing in terms of cognitive neuroscience. This is implemented and exemplified through processing characters. Using training inputs that are validated by the evolution of both barrier profile and domain configuration, accurate recalling of encoded characters in the retrieval stage is demonstrated.

Seismic evidence for multiple-stage exhumation of high/ultrahigh pressure metamorphic rocks in the eastern Dabie orogenic belt

Science.gov (United States)

Luo, Yinhe; Zhao, Kaifeng; Tang, Chi-Chia; Xu, Yixian

2018-05-01

The Dabie-Sulu orogenic belt in China contains one of the largest exposures of high and ultrahigh pressure (HP and UHP) metamorphic rocks in the world. The origin of HP/UHP metamorphic rocks and their exhumation to the surface in this belt have attracted great interest in the geologic community because the study of exhumation history of HP/UHP rocks helps to understand the process of continental-continental collision and the tectonic evolution of post-collision. However, the exhumation mechanism of the HP-UHP rocks to the surface is still contentious. In this study, by deploying 28 broadband seismic stations in the eastern Dabie orogenic belt and combining seismic data from 40 stations of the China National Seismic Network (CNSN), we image the high-resolution crustal isotropic shear velocity and radial anisotropy structure using ambient noise tomography. Our high-resolution 3D models provide new information about the exhumation mechanism of HP/UHP rocks and the origin of two dome structures.

6 March 2013 - Committee for Employment and Learning, Northern Ireland Legislative Assembly, United Kingdom of Great Britain and Northern Ireland in the LHC tunnel and visiting the LHCb experiment at LHC Point 8. Director for Accelerators and Technology S. Myers with Vice-Chair T. Buchanan.

CERN Multimedia

Anna Pantelia

2013-01-01

6 March 2013 - Committee for Employment and Learning, Northern Ireland Legislative Assembly, United Kingdom of Great Britain and Northern Ireland in the LHC tunnel and visiting the LHCb experiment at LHC Point 8. Director for Accelerators and Technology S. Myers with Vice-Chair T. Buchanan.

Enclosed belts in the ascendancy

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-03-15

Although there will always be a place for traditional overland belt conveyors, enclosed belt systems are increasingly being specified where environmental protection assumes high priority or where there is a need to protect material from the weather. The article reports on recent conveyor projects such as: an MRC cable Belt in a 6.4 km system to carry coal in the Appalachian Mountains; a $40 m contract awarded to FL Smidth to supply an integrated coal handling system to LILIAMA in Vietnam and other contracts to handle coal for India's Coastal Gujarat Power; and a contract awarded to Bateman Engineered Technologies to supply a 7 km Japan Pipe Conveyor for a coal power station in Brazil. 3 photos.

Intelligent Belt Conveyor Monitoring and Control

NARCIS (Netherlands)

Pang, Y.

2010-01-01

Belt conveyors have been used worldwide in continuous material transport for about 250 years. Traditional inspection and monitoring of large-scale belt conveyors focus on individual critical components and response to catastrophic system failures. To prevent operational problems caused by the lack

The Caucasian-Arabian segment of the Alpine-Himalayan collisional belt: Geology, volcanism and neotectonics

Directory of Open Access Journals (Sweden)

E. Sharkov

2015-07-01

Full Text Available The Caucasian-Arabian belt is part of the huge late Cenozoic Alpine-Himalayan orogenic belt formed by collision of continental plates. The belt consists of two domains: the Caucasian-Arabian Syntaxis (CAS in the south and the EW-striking Greater Caucasus in the north. The CAS marks a zone of the indentation of the Arabian plate into the southern East European Craton. The Greater Caucasus Range is located in the south of the Eurasian plate; it was tectonically uplifted along the Main Caucasian Fault (MCF, which is, in turn, a part of a megafault extended over a great distance from the Kopetdag Mts. to the Tornquist-Teisseyre Trans-European Suture Zone. The Caucasus Mts. are bounded by the Black Sea from the west and by the Caspian Sea from the east. The SN-striking CAS is characterized by a large geophysical isostatic anomaly suggesting presence of mantle plume head. A 500 km long belt of late Cenozoic volcanism in the CAS extends from the eastern Anatolia to the Lesser and Greater Caucasus ranges. This belt hosts two different types of volcanic rocks: (1 plume-type intraplate basaltic plateaus and (2 suprasubduction-type calc-alkaline and shoshonite-latite volcanic rocks. As the CAS lacks signatures of subduction zones and is characterized by relatively shallow earthquakes (50–60 km, we suggest that the “suprasubduction-type” magmas were derived by interaction between mantle plume head and crustal material. Those hybrid melts were originated under conditions of collision-related deformation. During the late Cenozoic, the width of the CAS reduced to ca. 400 km due to tectonic “diffluence” of crustal material provided by the continuing Arabia-Eurasia collision.

Handbook Timing Belts Principles, Calculations, Applications

CERN Document Server

Perneder, Raimund

2012-01-01

Timing belts offer a broad range of innovative drivetrain solutions; they allow low-backlash operation in robot systems, they are widely used in automated processes and industrial handling involving highly dynamic start-up loads, they are low-maintenance solutions for continuous operation applications, and they can guarantee exact positioning at high operating speeds. Based on his years of professional experience, the author has developed concise guidelines for the dimensioning of timing belt drives and presents proven examples from the fields of power transmission, transport and linear transfer technology. He offers definitive support for dealing with and compensating for adverse operating conditions and belt damage, as well as advice on drive optimization and guidelines for the design of drivetrain details and supporting systems. All market-standard timing belts are listed as brand neutral. Readers will discover an extensive bibliography with information on the various manufacturers and their websites. This...

EVALUATION OF SEISMIC PERFORMANCE OF RAMP TUNNEL STRUCTURE DURING LEVEL-2 EARTHQUAKE BY MASSIVE 3D NUMERICAL COMPUTATION

Science.gov (United States)

Yamada, Takemine; Ichimura, Tsuyoshi; Hori, Muneo; Dobashi, Hiroshi; Ohbo, Naoto

Quasi non-linear 3D FEM earthquake response analysises with level-2 earthquake are conducted for a ramp tunnel structure of Tokyo metropolitan express way central circular line the Yamate tunnel. Large-scale numerical computation with solid elements is highly required for examination of seismic response of large tunnel in case of level-2 earthquake. The results are obtained as follows: i) In level-2 earthquake, stress concentration in ramp tunnel becomes great near geological interface between two layers of high impedance contrast. ii) The response is not obtained as a superposition of two-dimensional responses which is an assumption in conventional design methods because the distribution of displacements in the direction of tunnel axis at cross-section of ramp tunnel structure near geological interface does not linearly distribute. iii) Evaluation of stress in addition to section force is desirable for the correct evaluation of the three-dimensional response of tunnel structure.

Energetic electrons in the inner belt in 1968

Energy Technology Data Exchange (ETDEWEB)

West, Jr, H I; Buck, R M [California Univ., Livermore (USA). Lawrence Livermore Lab.

1976-07-01

Pitch-angle data were obtained by the Lawrence Livermore Laboratory's scanning, magnetic electron spectrometer on OGO 5 during its traversals of the inner belt in 1968. Data from the five lowest-energy channels 79 to 822 keV, were analyzed. The inner-belt electron injection following two storm periods was observed; the first was the mild storm of 11 June and the second the more intense storms of 31 October and 1 November. Comparisons with other data indicate that only a small Starfish residual (at > 1 MeV) still remained in the heart of the inner belt; hence, the results are indicative of the normal inner belt. The data are discussed in terms of current ideas regarding the source and loss of particles in the inner belt.

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

Science.gov (United States)

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

2016-04-06

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

Magnetic tunnel junctions with monolayer hexagonal boron nitride tunnel barriers

Energy Technology Data Exchange (ETDEWEB)

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

2016-03-07

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

Variability in ACL tunnel placement: observational clinical study of surgeon ACL tunnel variability.

Science.gov (United States)

Wolf, Brian R; Ramme, Austin J; Wright, Rick W; Brophy, Robert H; McCarty, Eric C; Vidal, Armando R; Parker, Richard D; Andrish, Jack T; Amendola, Annunziato

2013-06-01

Multicenter and multisurgeon cohort studies on anterior cruciate ligament (ACL) reconstruction are becoming more common. Minimal information exists on intersurgeon and intrasurgeon variability in ACL tunnel placement. Purpose/ The purpose of this study was to analyze intersurgeon and intrasurgeon variability in ACL tunnel placement in a series of The Multicenter Orthopaedic Outcomes Network (MOON) ACL reconstruction patients and in a clinical cohort of ACL reconstruction patients. The hypothesis was that there would be minimal variability between surgeons in ACL tunnel placement. Cross-sectional study; Level of evidence, 3. Seventy-eight patients who underwent ACL reconstruction by 8 surgeons had postoperative imaging with computed tomography, and ACL tunnel location and angulation were analyzed using 3-dimensional surface processing and measurement. Intersurgeon and intrasurgeon variability in ACL tunnel placement was analyzed. For intersurgeon variability, the range in mean ACL femoral tunnel depth between surgeons was 22%. For femoral tunnel height, there was a 19% range. Tibial tunnel location from anterior to posterior on the plateau had a 16% range in mean results. There was only a small range of 4% for mean tibial tunnel location from the medial to lateral dimension. For intrasurgeon variability, femoral tunnel depth demonstrated the largest ranges, and tibial tunnel location from medial to lateral on the plateau demonstrated the least variability. Overall, surgeons were relatively consistent within their own cases. Using applied measurement criteria, 85% of femoral tunnels and 90% of tibial tunnels fell within applied literature-based guidelines. Ninety-one percent of the axes of the femoral tunnels fell within the boundaries of the femoral footprint. The data demonstrate that surgeons performing ACL reconstructions are relatively consistent between each other. There is, however, variability of average tunnel placement up to 22% of mean condylar depth

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

OpenAIRE

Font Capó, Jordi

2012-01-01

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

Belt design central to conveyor performance

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-07-15

While a conveyor system comprises a complex range of components, it is the belt design which ultimately dictates its core performance and reliability. The complexity of modern systems can be seen by the recent contract awarded to ThyssenKrupp Foerdertechnik (TKF) to supply systems for a new steel plant (including a coking plant and a power plant) to be built in Sepetiba Bay in Brazil. Phoenix has designed the Phoenotec system to protect steel cord conveyor belts. Fenner Dunlop has developed Fenaplast belting with nylon or polyester load-bearing warp and weft yarns for good impact resistance. 2 photos.

A New Reliability Analysis Model of the Chegongzhuang Heat-Supplying Tunnel Structure Considering the Coupling of Pipeline Thrust and Thermal Effect

Directory of Open Access Journals (Sweden)

Jiawen Zhang

2018-02-01

Full Text Available Based on the operating Chegongzhuang heat-supplying tunnel in Beijing, the reliability of its lining structure under the action of large thrust and thermal effect is studied. According to the characteristics of a heat-supplying tunnel service, a three-dimensional numerical analysis model was established based on the mechanical tests on the in-situ specimens. The stress and strain of the tunnel structure were obtained before and after the operation. Compared with the field monitoring data, the rationality of the model was verified. After extracting the internal force of the lining structure, the improved method of subset simulation was proposed as the performance function to calculate the reliability of the main control section of the tunnel. In contrast to the traditional calculation method, the analytic relationship between the sample numbers in the subset simulation method and Monte Carlo method was given. The results indicate that the lining structure is greatly influenced by coupling in the range of six meters from the fixed brackets, especially the tunnel floor. The improved subset simulation method can greatly save computation time and improve computational efficiency under the premise of ensuring the accuracy of calculation. It is suitable for the reliability calculation of tunnel engineering, because “the lower the probability, the more efficient the calculation.”

Geography of the asteroid belt

Science.gov (United States)

Zellner, B. H.

1978-01-01

The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

Field enhanced luminescence of irradiated organics due to electron tunnelling

International Nuclear Information System (INIS)

Charlesby, A.

1981-01-01

Many organic materials, following exposure to high energy radiation at low temperatures, continue to emit light for long periods. One possible mechanism is that electrons trapped near their parent cations can tunnel back over long times depending on trap depth and distance. This luminescence can be greatly enhanced by the post-radiation application of an external electric field. Calculations on the kinetics of recombination by tunnelling for various trap depths and distances are extended to allow for the effect of an electrical field subsequently applied. The quantitative results lead to two methods of assessing trap depth, depending on immediate light enhancement and on its subsequent decay. The effect of field reversal is also explained. (author)

Giant fifth-order nonlinearity via tunneling induced quantum interference in triple quantum dots

Directory of Open Access Journals (Sweden)

Si-Cong Tian

2015-02-01

Full Text Available Schemes for giant fifth-order nonlinearity via tunneling in both linear and triangular triple quantum dots are proposed. In both configurations, the real part of the fifth-order nonlinearity can be greatly enhanced, and simultaneously the absorption is suppressed. The analytical expression and the dressed states of the system show that the two tunnelings between the neighboring quantum dots can induce quantum interference, resulting in the giant higher-order nonlinearity. The scheme proposed here may have important applications in quantum information processing at low light level.

Electrical control of memristance and magnetoresistance in oxide magnetic tunnel junctions

KAUST Repository

Zhang, Kun

2015-01-01

Electric-field control of magnetic and transport properties of magnetic tunnel junctions has promising applications in spintronics. Here, we experimentally demonstrate a reversible electrical manipulation of memristance, magnetoresistance, and exchange bias in Co/CoO–ZnO/Co magnetic tunnel junctions, which enables the realization of four nonvolatile resistance states. Moreover, greatly enhanced tunneling magnetoresistance of 68% was observed due to the enhanced spin polarization of the bottom Co/CoO interface. The ab initio calculations further indicate that the spin polarization of the Co/CoO interface is as high as 73% near the Fermi level and plenty of oxygen vacancies can induce metal–insulator transition of the CoO1−v layer. Thus, the electrical manipulation mechanism on the memristance, magnetoresistance and exchange bias can be attributed to the electric-field-driven migration of oxygen ions/vacancies between very thin CoO and ZnO layers.

Klippen Belt, Flysch Belt and Inner Western Carpathian Paleogene Basin Relations in the Northern Slovakia by Magnetotelluric Imaging

Czech Academy of Sciences Publication Activity Database

Majcin, D.; Bezák, V.; Klanica, Radek; Vozár, J.; Pek, Josef; Bilčík, D.; Telecký, Josef

(2018) ISSN 0033-4553 Institutional support: RVO:67985530 Keywords : magnetotellurics * Western Carpathians * Klippen Belt * Flysch Belt * Inner Carpathian Paleogene Subject RIV: DE - Earth Magnetism, Geodesy, Geography OBOR OECD: Physical geography Impact factor: 1.591, year: 2016

Full waveform inversion for mechanized tunneling reconnaissance

Science.gov (United States)

Lamert, Andre; Musayev, Khayal; Lambrecht, Lasse; Friederich, Wolfgang; Hackl, Klaus; Baitsch, Matthias

2016-04-01

In mechanized tunnel drilling processes, exploration of soil structure and properties ahead of the tunnel boring machine can greatly help to lower costs and improve safety conditions during drilling. We present numerical full waveform inversion approaches in time and frequency domain of synthetic acoustic data to detect different small scale structures representing potential obstacles in front of the tunnel boring machine. With the use of sensitivity kernels based on the adjoint wave field in time domain and in frequency domain it is possible to derive satisfactory models with a manageable amount of computational load. Convergence to a suitable model is assured by the use of iterative model improvements and gradually increasing frequencies. Results of both, time and frequency approach, will be compared for different obstacle and source/receiver setups. They show that the image quality strongly depends on the used receiver and source positions and increases significantly with the use of transmission waves due to the installed receivers and sources at the surface and/or in bore holes. Transmission waves lead to clearly identified structure and position of the obstacles and give satisfactory guesses for the wave speed. Setups using only reflected waves result in blurred objects and ambiguous position of distant objects and allow to distinguish heterogeneities with higher or lower wave speed, respectively.

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-08-01

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

Study on transmitting mechanisms for CVT using a dry hybrid belt. Numerical simulation of transmitting forces and pulley thrusts at steady and transitional states; Kanshiki fukugo belt wo mochiita CVT ni kansuru kenkyu. Teijo oyobi hensokuji ni okeru dentatsuryoku to pulley suiryoku no suchi simulation

Energy Technology Data Exchange (ETDEWEB)

Miyazawa, T; Kuwabara, S; Fujii, T [Doshisha University, Kyoto (Japan); Nonaka, K [Bando Chemical Industries, Ltd., Kobe (Japan)

1997-10-01

A numerical model was developed to analyze the power transmitting mechanisms for CVT (Continuous Variable Transmissions) using a dry hybrid belt. The model consists of linear springs representing the rigidities of blocks, rubber and cord, and interface elements which identify slippage between pulleys and blocks. By using the present model, forces acting on the belt were calculated not only at steady but also transitional states. Calculated results well coincide with experimental ones. It is revealed that there is a great change of the pulley thrust when the speed ratio is shifting. Little radial slippage occurs when the pulley groove is reduced. 1 ref., 9 figs.

Carpal Tunnel Syndrome

Science.gov (United States)

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

Theory of superconducting tunneling without the tunneling Hamiltonian

International Nuclear Information System (INIS)

Arnold, G.B.

1987-01-01

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

14 CFR 125.211 - Seat and safety belts.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Seat and safety belts. 125.211 Section 125... Requirements § 125.211 Seat and safety belts. (a) No person may operate an airplane unless there are available... the airplane who is at least 2 years old; and (2) An approved safety belt for separate use by each...

Belt Conveyor Dynamic Characteristics and Influential Factors

Directory of Open Access Journals (Sweden)

Junxia Li

2018-01-01

Full Text Available This paper uses the Kelvin-Voigt viscoelastic model to establish the continuous dynamic equations for tail hammer tension belt conveyors. The viscoelastic continuity equations are solved using the generalized coordinate method. We analyze various factors influencing longitudinal vibration of the belt conveyor by simulation and propose a control strategy to limit the vibration. The proposed approach and control strategy were verified by several experimental researches and cases. The proposed approach provides improved accuracy for dynamic design of belt conveyors.

Tunneling works. Tunnel koji

Energy Technology Data Exchange (ETDEWEB)

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

1991-10-25

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

Space Weather Effects in the Earth's Radiation Belts

Science.gov (United States)

Baker, D. N.; Erickson, P. J.; Fennell, J. F.; Foster, J. C.; Jaynes, A. N.; Verronen, P. T.

2018-02-01

The first major scientific discovery of the Space Age was that the Earth is enshrouded in toroids, or belts, of very high-energy magnetically trapped charged particles. Early observations of the radiation environment clearly indicated that the Van Allen belts could be delineated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. The energy distribution, spatial extent and particle species makeup of the Van Allen belts has been subsequently explored by several space missions. Recent observations by the NASA dual-spacecraft Van Allen Probes mission have revealed many novel properties of the radiation belts, especially for electrons at highly relativistic and ultra-relativistic kinetic energies. In this review we summarize the space weather impacts of the radiation belts. We demonstrate that many remarkable features of energetic particle changes are driven by strong solar and solar wind forcings. Recent comprehensive data show broadly and in many ways how high energy particles are accelerated, transported, and lost in the magnetosphere due to interplanetary shock wave interactions, coronal mass ejection impacts, and high-speed solar wind streams. We also discuss how radiation belt particles are intimately tied to other parts of the geospace system through atmosphere, ionosphere, and plasmasphere coupling. The new data have in many ways rewritten the textbooks about the radiation belts as a key space weather threat to human technological systems.

Tunneling junction as an open system. Normal tunneling

International Nuclear Information System (INIS)

Ono, Y.

1978-01-01

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

Estimation of Rheological Properties of Viscous Debris Flow Using a Belt Conveyor

Science.gov (United States)

Hübl, J.; Steinwendtner, H.

2000-09-01

Rheological parameters of viscous debris flows are influenced by a great amount of factors and are therefore extremely difficult to estimate. Because of this uncertainties a belt conveyor (conveyor channel) was constructed to measure flow behaviour and rheological properties of natural debris flow material. The upward movement of the smooth rubberised belt between fixed lateral plastic walls causes a stationary wave relative to these bends. This special experimental design enables to study behaviour of viscous ebris flow material with maximum grain diameters up to 20 mm within several minutes and to hold measuring equipment very simple. The conveyor channel was calibrated first with Xanthan, a natural polysaccharide used as thickener in food technology, whose rheological properties are similar to viscous debris flow material. In a second step natural debris flow material was investigated. Velocities and rheological parameters were measured with varying solid concentration and slope of the channel. In cases where concentration of coarse particles exceed around 15% by volume the conveyor channel obtains an alternative to expensive commercial viscometers for determination of rheological parameters of viscous debris flows.

Rashba and Dresselhaus spin-orbit coupling effects on tunnelling through two-dimensional magnetic quantum systems

International Nuclear Information System (INIS)

Xu Wen; Guo Yong

2005-01-01

We investigate the influence of the Rashba and Dresselhaus spin-orbit coupling interactions on tunnelling through two-dimensional magnetic quantum systems. It is showed that not only Rashba spin-orbit coupling but also Dresselhaus one can affect spin tunnelling properties greatly in such a quantum system. The transmission possibility, the spin polarization and the conductance are obviously oscillated with both coupling strengths. High spin polarization, conductance and magnetic conductance of the structure can be obtained by modulating either Rashba or Dresselhaus coupling strength

An Empirical Planetesimal Belt Radius–Stellar Luminosity Relation

Science.gov (United States)

Matrà, L.; Marino, S.; Kennedy, G. M.; Wyatt, M. C.; Öberg, K. I.; Wilner, D. J.

2018-05-01

Resolved observations of millimeter-sized dust, tracing larger planetesimals, have pinpointed the location of 26 Edgeworth–Kuiper Belt analogs. We report that a belt’s distance R to its host star correlates with the star’s luminosity L ⋆, following R\\propto {L}\\star 0.19 with a low intrinsic scatter of ∼17%. Remarkably, our Edgeworth–Kuiper Belt in the solar system and the two CO snow lines imaged in protoplanetary disks lie close to this R–L ⋆ relation, suggestive of an intrinsic relationship between protoplanetary disk structures and belt locations. To test the effect of bias on the relation, we use a Monte Carlo approach and simulate uncorrelated model populations of belts. We find that observational bias could produce the slope and intercept of the R–L ⋆ relation but is unable to reproduce its low scatter. We then repeat the simulation taking into account the collisional evolution of belts, following the steady-state model that fits the belt population as observed through infrared excesses. This significantly improves the fit by lowering the scatter of the simulated R–L ⋆ relation; however, this scatter remains only marginally consistent with the one observed. The inability of observational bias and collisional evolution alone to reproduce the tight relationship between belt radius and stellar luminosity could indicate that planetesimal belts form at preferential locations within protoplanetary disks. The similar trend for CO snow line locations would then indicate that the formation of planetesimals or planets in the outer regions of planetary systems is linked to the volatility of their building blocks, as postulated by planet formation models.

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

International Nuclear Information System (INIS)

Teeny, Nicolas

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Teeny, Nicolas

2016-10-18

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

TUNNEL POINT CLOUD FILTERING METHOD BASED ON ELLIPTIC CYLINDRICAL MODEL

Directory of Open Access Journals (Sweden)

N. Zhu

2016-06-01

Full Text Available The large number of bolts and screws that attached to the subway shield ring plates, along with the great amount of accessories of metal stents and electrical equipments mounted on the tunnel walls, make the laser point cloud data include lots of non-tunnel section points (hereinafter referred to as non-points, therefore affecting the accuracy for modeling and deformation monitoring. This paper proposed a filtering method for the point cloud based on the elliptic cylindrical model. The original laser point cloud data was firstly projected onto a horizontal plane, and a searching algorithm was given to extract the edging points of both sides, which were used further to fit the tunnel central axis. Along the axis the point cloud was segmented regionally, and then fitted as smooth elliptic cylindrical surface by means of iteration. This processing enabled the automatic filtering of those inner wall non-points. Experiments of two groups showed coincident results, that the elliptic cylindrical model based method could effectively filter out the non-points, and meet the accuracy requirements for subway deformation monitoring. The method provides a new mode for the periodic monitoring of tunnel sections all-around deformation in subways routine operation and maintenance.

On-conveyor belt determination of ash in coal

International Nuclear Information System (INIS)

Sowerby, B.; Lim, C.S.; Abernethy, D.A.; Liu, Y.; Maguire, P.A.

1997-01-01

A laboratory feasibility study has been carried out on new and advanced neutron and gamma-ray analysis systems for the direct on-conveyor belt analysis of ash in coal without the need for sample by-lines. Such an analysis system could deliver the combined advantages of a direct on-conveyor configuration with new and accurate analysis techniques. An industry survey of 18 coal companies carried out in early 1996 indicated that accurate on-belt ash analysis is of the highest priority. Subsequent laboratory work has focussed on the investigation of methods with the potential for improving the accuracy of ash content measurement relative to existing on-belt ash analysers, the most widely-used of which are based on dual energy gamma-ray transmission (DUET), which is sensitive to variations in ash composition. The current work indicates that on-belt neutron/gamma-ray techniques combined with advanced spectral analysis techniques show promise for development into an on-belt ash analysis system which is significantly less sensitive to composition changes than DUET and which analyses a much larger proportion of coal on the belt, thus eliminating some key sources of analysis error

Quantum theory of tunneling

CERN Document Server

Razavy, Mohsen

2014-01-01

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

36 CFR 1004.15 - Safety belts.

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Safety belts. 1004.15 Section 1004.15 Parks, Forests, and Public Property PRESIDIO TRUST VEHICLES AND TRAFFIC SAFETY § 1004.15 Safety... administered by the Presidio Trust will have the safety belt or child restraint system properly fastened at all...

Estimates Of Radiation Belt Remediation Requirements

Science.gov (United States)

Tuszewski, M.; Hoyt, R. P.; Minor, B. M.

2004-12-01

A low-Earth orbit nuclear detonation could produce an intense artificial radiation belt of relativistic electrons. Many satellites would be destroyed within a few weeks. We present here simple estimates of radiation belt remediation by several different techniques, including electron absorption by gas release, pitch angle scattering by steady electric and magnetic fields from tether arrays, and pitch angle scattering by wave-particle interactions from in-situ transmitters. For each technique, the mass, size, and power requirements are estimated for a one-week remediation (e-folding) timescale, assuming that a 10 kTon blast trapped 1024 fission product electrons (1 to 8 MeV) at L = 1.5 in a dipolar belt of width dL = 0.1.

Inelastic tunneling of electrons through a quantum dot with an embedded single molecular magnet

Science.gov (United States)

Chang, Bo; Liang, J.-Q.

2010-06-01

We report a theoretical analysis of electron transport through a quantum dot with an embedded biaxial single-molecule magnet (SMM) based on mapping of the many-body interaction-system onto a one-body problem by means of the non-equilibrium Green function technique. It is found that the conducting current exhibits a stepwise behavior and the nonlinear differential conductance displays additional peaks with variation of the sweeping speed and the magnitude of magnetic field. This observation can be interpreted by the interaction of electron-spin with the SMM and the quantum tunneling of magnetization. The inelastic conductance and the corresponding tunneling processes are investigated with normal as well as ferromagnetic electrodes. In the case of ferromagnetic configuration, the coupling to the SMM leads to an asymmetric tunneling magnetoresistance (TMR), which can be enhanced or suppressed greatly in certain regions. Moreover, a sudden TMR-switch with the variation of magnetic field is observed, which is seen to be caused by the inelastic tunneling.

Inelastic tunneling of electrons through a quantum dot with an embedded single molecular magnet

Energy Technology Data Exchange (ETDEWEB)

Chang Bo [Institute of Theoretical Physics and Department of Physics, Shanxi University, Taiyuan, Shanxi 030006 (China); Liang, J.-Q., E-mail: jqliang@sxu.edu.c [Institute of Theoretical Physics and Department of Physics, Shanxi University, Taiyuan, Shanxi 030006 (China)

2010-06-28

We report a theoretical analysis of electron transport through a quantum dot with an embedded biaxial single-molecule magnet (SMM) based on mapping of the many-body interaction-system onto a one-body problem by means of the non-equilibrium Green function technique. It is found that the conducting current exhibits a stepwise behavior and the nonlinear differential conductance displays additional peaks with variation of the sweeping speed and the magnitude of magnetic field. This observation can be interpreted by the interaction of electron-spin with the SMM and the quantum tunneling of magnetization. The inelastic conductance and the corresponding tunneling processes are investigated with normal as well as ferromagnetic electrodes. In the case of ferromagnetic configuration, the coupling to the SMM leads to an asymmetric tunneling magnetoresistance (TMR), which can be enhanced or suppressed greatly in certain regions. Moreover, a sudden TMR-switch with the variation of magnetic field is observed, which is seen to be caused by the inelastic tunneling.

Modeling of Jupiter's electron an ion radiation belts

International Nuclear Information System (INIS)

Sicard, Angelica

2004-01-01

In the Fifties, James Van Allen showed the existence of regions of the terrestrial magnetosphere consisted of energetic particles, trapped by the magnetic field: the radiation belts. The radiation belts of the Earth were the subject of many modeling works and are studied since several years at the Departement Environnement Spatial (DESP) of ONERA. In 1998, the DESP decided to adapt the radiation belts model of the Earth, Salammbo, to radiation environment of Jupiter. A first thesis was thus carried out on the subject and a first radiation belts model of electrons of Jupiter was developed [Santos-Costa, 2001]. The aim of this second thesis is to develop a radiation belts model for protons and heavy ions. In order to validate the developed model, the comparisons between Salammbo results and observations are essential. However, the validation is difficult in the case of protons and heavy ions because in-situ measurements of the probes are very few and most of the time contaminated by very energetic electrons. To solve this problem, a very good model of electrons radiation belts is essential to confirm or cancel the contamination of protons and heavy ions measurements. Thus, in parallel to the development of the protons and heavy ions radiation belts model, the electrons models, already existing, has been improved. Then Salammbo results have been compared to the different observations available (in-situ measurements, radio-astronomical observations). The different comparisons show a very good agreement between Salammbo results and observations. (author) [fr

Mesin Pemindah Bahan : Studi Prestasi Belt Conveyor Hubungannya Dengan Ukuran Butiran Dan Tingkat Kelembaban Bahan Curah ( Batubara ), Panjang Belt 7,6 Meter ; Lebar 32 Centimeter

OpenAIRE

Nugroho, Rio

2011-01-01

Banyak industri yang menggunakan belt conveyor sebagai alat transportasi material, sebab punya banyak keuntungan. Sehingga, untuk meningkatkan performansi belt conveyor tersebut perlu dilakukan pengidentifikasian prestasi belt conveyor. Identifikasi dilakukan dengan material transfer batubara. Yang akan diamati adalah pengaruh ukuran butiran material dan tingkat kelembaban terhadap kapasitas transfer belt conveyor. Dari pengujian didapatkan kapasitas transfer terbesar adalah material batubar...

Survey of current situation in radiation belt modeling

Science.gov (United States)

Fung, Shing F.

2004-01-01

The study of Earth's radiation belts is one of the oldest subjects in space physics. Despite the tremendous progress made in the last four decades, we still lack a complete understanding of the radiation belts in terms of their configurations, dynamics, and detailed physical accounts of their sources and sinks. The static nature of early empirical trapped radiation models, for examples, the NASA AP-8 and AE-8 models, renders those models inappropriate for predicting short-term radiation belt behaviors associated with geomagnetic storms and substorms. Due to incomplete data coverage, these models are also inaccurate at low altitudes (e.g., <1000 km) where many robotic and human space flights occur. The availability of radiation data from modern space missions and advancement in physical modeling and data management techniques have now allowed the development of new empirical and physical radiation belt models. In this paper, we will review the status of modern radiation belt modeling. Published by Elsevier Ltd on behalf of COSPAR.

Wearing an abdominal belt increases diastolic blood pressure.

Science.gov (United States)

Rafacz, W; McGill, S M

1996-09-01

The purpose of this study was to determine the effect of wearing an abdominal belt on blood pressure (systolic and diastolic) and heart rate during a variety of tasks. The belt was typical of the elastic type with suspenders and Velcro tabs for cinching the belt snug. The tasks performed included sitting at rest, sitting with the torso inclined forward at 45 degrees, standing with the torso inclined forward at 45 degrees (with and without holding an 11-kg weight), a trunk axial rotation task, and squat lifting. Blood pressure was monitored noninvasively with a FINAPRES blood pressure monitor. Twenty healthy men performed each task with and without the abdominal belt. Although no significant increases in mean systolic blood pressure or heart rate were found, there was a significant increase in diastolic blood pressure in all conditions. All people considering wearing an abdominal belt should also consider the risks and liability associated with the additional cardiovascular load, particularly heart attack and stroke.

Spin-dependent tunnelling in magnetic tunnel junctions

International Nuclear Information System (INIS)

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

2003-01-01

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

Study on a metal pushing V-belt type CVT. Numerical analysis for belt tension distribution in brands of a ring at steady state; Kinzoku V belt wo mochiita CVT ni kansuru kenkyu. Sekiso belt (steel ring) no dendo kiko kaiseki

Energy Technology Data Exchange (ETDEWEB)

Fujii, T; Kuwabara, S [Doshisha University, Kyoto (Japan); Kanehara, S [Honda Motor Co. Ltd., Tokyo (Japan)

1997-10-01

The power transmitting mechanisms for laminated belts were studied to analyze belt tension in each band of the ring of metal V-belts. A numerical model consisting of linear springs and frictional elements was proposed. The present model was experimentally proved. It is revealed based on the numerical results that each band shares the ring tension equally when the coefficients of friction for bands and a pulley are the same while the first band must support more when the coefficients of friction between two bands are lower than that between a saddle surface of the block and the inner band. 4 refs., 9 figs.

Wind Tunnel Management and Resource Optimization: A Systems Modeling Approach

Science.gov (United States)

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

2000-01-01

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

An Effective Belt Conveyor for Underground Ore Transportation Systems

Science.gov (United States)

Krol, Robert; Kawalec, Witold; Gladysiewicz, Lech

2017-12-01

Raw material transportation generates a substantial share of costs in the mining industry. Mining companies are therefore determined to improve the effectiveness of their transportation system, focusing on solutions that increase both its energy efficiency and reliability while keeping maintenance costs low. In the underground copper ore operations in Poland’s KGHM mines vast and complex belt conveyor systems have been used for horizontal haulage of the run-of-mine ore from mining departments to shafts. Basing upon a long-time experience in the field of analysing, testing, designing and computing of belt conveyor equipment with regard to specific operational conditions, the improvements to the standard design of an underground belt conveyor for ore transportation have been proposed. As the key elements of a belt conveyor, the energy-efficient conveyor belt and optimised carrying idlers have been developed for the new generation of underground conveyors. The proposed solutions were tested individually on the specially constructed test stands in the laboratory and in the experimental belt conveyor that was built up with the use of prototype parts and commissioned for the regular ore haulage in a mining department in the KGHM underground mine “Lubin”. Its work was monitored and the recorded operational parameters (loadings, stresses and strains, energy dissipation, belt tracking) were compared with those previously collected on a reference (standard) conveyor. These in-situ measurements have proved that the proposed solutions will return with significant energy savings and lower maintenance costs. Calculations made on the basis of measurement results in the specialized belt conveyor designing software allow to estimate the possible savings if the modernized conveyors supersede the standard ones in a large belt conveying system.

Modeling and energy efficiency optimization of belt conveyors

International Nuclear Information System (INIS)

Zhang, Shirong; Xia, Xiaohua

2011-01-01

Highlights: → We take optimization approach to improve operation efficiency of belt conveyors. → An analytical energy model, originating from ISO 5048, is proposed. → Then an off-line and an on-line parameter estimation schemes are investigated. → In a case study, six optimization problems are formulated with solutions in simulation. - Abstract: The improvement of the energy efficiency of belt conveyor systems can be achieved at equipment and operation levels. Specifically, variable speed control, an equipment level intervention, is recommended to improve operation efficiency of belt conveyors. However, the current implementations mostly focus on lower level control loops without operational considerations at the system level. This paper intends to take a model based optimization approach to improve the efficiency of belt conveyors at the operational level. An analytical energy model, originating from ISO 5048, is firstly proposed, which lumps all the parameters into four coefficients. Subsequently, both an off-line and an on-line parameter estimation schemes are applied to identify the new energy model, respectively. Simulation results are presented for the estimates of the four coefficients. Finally, optimization is done to achieve the best operation efficiency of belt conveyors under various constraints. Six optimization problems of a typical belt conveyor system are formulated, respectively, with solutions in simulation for a case study.

"Abomination"--life as a Bible belt gay.

Science.gov (United States)

Barton, Bernadette

2010-01-01

Drawing on observation, autoethnography, and audio-taped interviews, this article explores the religious backgrounds and experiences of Bible Belt gays. In the Bible Belt, Christianity is not confined to Sunday worship. Christian crosses, messages, paraphernalia, music, news, and attitudes permeate everyday settings. Consequently, Christian fundamentalist dogma about homosexuality-that homosexuals are bad, diseased, perverse, sinful, other, and inferior-is cumulatively bolstered within a variety of other social institutions and environments in the Bible Belt. Of the 46 lesbians and gay men interviewed for this study (age 18-74 years), most describe living through spirit-crushing experiences of isolation, abuse, and self-loathing. This article argues that the geographic region of the Bible Belt intersects with religious-based homophobia. Informants explained that negative social attitudes about homosexuality caused a range of harmful consequences in their lives including the fear of going to hell, depression, low self-esteem, and feelings of worthlessness.

Molecular-Beam Epitaxially Grown MgB2 Thin Films and Superconducting Tunnel Junctions

Directory of Open Access Journals (Sweden)

Jean-Baptiste Laloë

2011-01-01

Full Text Available Since the discovery of its superconducting properties in 2001, magnesium diboride has generated terrific scientific and engineering research interest around the world. With a of 39 K and two superconducting gaps, MgB2 has great promise from the fundamental point of view, as well as immediate applications. Several techniques for thin film deposition and heterojunction formation have been established, each with its own advantages and drawbacks. Here, we will present a brief overview of research based on MgB2 thin films grown by molecular beam epitaxy coevaporation of Mg and B. The films are smooth and highly crystalline, and the technique allows for virtually any heterostructure to be formed, including all-MgB2 tunnel junctions. Such devices have been characterized, with both quasiparticle and Josephson tunneling reported. MgB2 remains a material of great potential for a multitude of further characterization and exploration research projects and applications.

Gravity inferred subsurface structure of Gadwal Schist belt, Andhra

Indian Academy of Sciences (India)

Detailed gravity data collected across the Gadwal schist belt in the state of Andhra Pradesh show an 8.4 mgal residual gravity anomaly associated with meta-sediments/volcanics of the linear NNW-SSE trending schist belt that shows metamorphism from green schist to amphibolite facies. This schist belt is flanked on either ...

Tunnel fire dynamics

CERN Document Server

Ingason, Haukur; Lönnermark, Anders

2015-01-01

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

Using haptic feedback to increase seat belt use : traffic tech.

Science.gov (United States)

2011-07-01

The legacy of research on increasing seat belt use has : focused on enactment of seat belt legislation, public education, : high-visibility police enforcement, and seat belt : reminder systems. Several behavioral programs have : produced large, susta...

Seat belt injuries and sigmoid colon trauma.

OpenAIRE

Eltahir, E M; Hamilton, D

1997-01-01

Colonic seat belt injuries are rare but carry higher mortality rates than small bowel injuries. The case of a 44 year old man is described who had severe sigmoid colon compression injury from his seat belt a few days after a road traffic accident.

Proton tunneling in solids

Energy Technology Data Exchange (ETDEWEB)

Kondo, J.

1998-10-01

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

Proton tunneling in solids

International Nuclear Information System (INIS)

Kondo, J.

1998-01-01

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

Radiometric measurement independent of profile. Belt weighers

International Nuclear Information System (INIS)

Otto, J.

1986-01-01

Radiometric measuring techniques allow contactless determination of the material carried by belt conveyors. Data defining the material is obtained via attenuation of gamma rays passing through the material on the belt. The method applies the absorption law according to Lambert-Beer, which has to be corrected by a build-up factor because of the stray radiation induced by the Compton effect. The profile-dependent error observed with conventional radiometric belt weighers is caused by the non-linearity of the absorption law in connection with the simultaneous summation of the various partial rays in a detector. The scanning method allows separate evaluation of the partial rays' attenuation and thus yields the correct data of the material carried, regardless of the profile. The scanning method is applied on a finite number of scanning sections, and a residual error has to be taken into account. The stochastics of quantum emission and absorption leads to an error whose expectation value is to be taken into account in the scanning algorithm. As the conveyor belt is in motion during the process of measurements, only part of the material conveyed is irradiated. The resulting assessment error is investigated as a function of the autocorrelation function of the material on the belt. (orig./HP) [de

Electron spin resonance scanning tunneling microscope

International Nuclear Information System (INIS)

Guo Yang; Li Jianmei; Lu Xinghua

2015-01-01

It is highly expected that the future informatics will be based on the spins of individual electrons. The development of elementary information unit will eventually leads to novel single-molecule or single-atom devices based on electron spins; the quantum computer in the future can be constructed with single electron spins as the basic quantum bits. However, it is still a great challenge in detection and manipulation of a single electron spin, as well as its coherence and entanglement. As an ideal experimental tool for such tasks, the development of electron spin resonance scanning tunneling microscope (ESR-STM) has attracted great attention for decades. This paper briefly introduces the basic concept of ESR-STM. The development history of this instrument and recent progresses are reviewed. The underlying mechanism is explored and summarized. The challenges and possible solutions are discussed. Finally, the prospect of future direction and applications are presented. (authors)

A comparison of muscle activation between back squats and belt squats.

Science.gov (United States)

Evans, Thomas W; McLester, Cherilyn N; Howard, Jonathan H; McLester, John R; Calloway, Jimmy P

2017-06-08

A machine belt squat is a piece of equipment designed to allow the performance of squats while loading weight on the lifter's hips using a belt. The purpose of this investigation was to determine if belt squats differ from back squats in activation of the primary movers, and to determine the predictive capabilities of back squat load, training status, and anthropometric data on belt squat load. Thirty-one participants (16 males and 15 females) completed anthropometric measurements, a demographic questionnaire, a familiarization visit, and two testing visits, completing a 5 repetition maximum test for back squat and belt squat. Surface electromyography was used to measure muscle activation for the left and right vastus medialis (VMO), vastus lateralis (VLO), rectus femoris (RF), and gluteus maximus (GM). Comparison of muscle activation between the two exercises showed significant differences in the left GM (back squat: 0.84 ± 0.45, belt squat: 0.69 ± 0.22, p=0.015) and right GM (back squat: 0.86 ± 0.45, belt squat: 0.71 ± 0.29, p=0.004). Regression analysis computed significant prediction equations for belt squat load for general population, males, females, and advanced lifters. Overall, results indicate that belt squats may significantly differ in GM activation from back squats. Back squat load, as well as other variables, may be effective in accurately estimating appropriate belt squat load. These findings may help to more appropriately program for training with machine belt squats as a back squat alternative.

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

Science.gov (United States)

Gikas, Vassilis

2012-01-01

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. PMID:23112655

PRESENTDAY STRESS STATE OF THE SHANXI TECTONIC BELT

Directory of Open Access Journals (Sweden)

Wang Kaiying

2012-01-01

Full Text Available The Shanxi tectonic belt is a historically earthquakeabundant area. For the majority of strong earthquakes in this area, the distribution of earthquake foci was controlled by the N–S oriented local structures on the tectonic belt. Studies of the present stress state of the Shanxi tectonic belt can contribute to the understanding of the relationship between strong earthquakes’ occurrence and their structural distribution and also facilitate assessments of regional seismic danger and determination of the regions wherein strong earthquakes may occur in future. Using the Cataclastic Analysis Method (CAM, we performed stress inversion based on the focal mechanism data of earthquakes which took place in the Shanxi tectonic belt from 1967 to 2010. Our results show that orientations of the maximum principal compressive stress axis of the Shanxi tectonic belt might have been variable before and after the 2001 Kunlun MS=8.1 strong earthquake, with two different superior trends of the NW–SE and NE–SW orientation in different periods. When the maximum principal compressive stress axis is oriented in the NE–SW direction, the pattern of the space distribution of the seismic events in the Shanxi tectonic belt shows a trend of their concentration in the N–S oriented tectonic segments. At the same time, the stress state is registered as horizontal shearing and horizontal extension in the N–S and NE–SW oriented local segments in turn. When the maximum principal compressive stress axis is NW–SE oriented, the stress state of the N–S and NE–SW oriented tectonic segments is primarily registered as horizontal shearing. Estimations of plunges of stress axes show that seismicity in the Shanxi belt  corresponds primarily to the activity of lowangle faults, and highangle stress sites are located in the NE–SW oriented extensional tectonic segments of the Shanxi belt. This indicates that the stress change of the Shanxi belt is

Compressed air tunneling and caisson work decompression procedures: development, problems, and solutions.

Science.gov (United States)

Kindwall, E P

1997-01-01

Multinational experience over many years indicates that all current air decompression schedules for caisson and compressed air tunnel workers are inadequate. All of them, including the Occupational Safety and Health Administration tables, produce dysbaric osteonecrosis. The problem is compounded because decompression sickness (DCS) tends to be underreported. Permanent damage in the form of central nervous system or brain damage may occur in compressed air tunnel workers, as seen on magnetic resonance imaging, in addition to dysbaric osteonecrosis. Oxygen decompression seems to be the only viable method for safely decompressing tunnel workers. Oxygen decompression of tunnel workers has been successfully used in Germany, France, and Brazil. In Germany, only oxygen decompression of compressed air workers is permitted. In our experience, U.S. Navy tables 5 and 6 usually prove adequate to treat DCS in caisson workers despite extremely long exposure times, allowing patients to return to work following treatment for DCS. Tables based on empirical data and not on mathematical formulas seem to be reasonably safe. U.S. Navy Exceptional Exposure Air Decompression tables are compared with caisson tables from the United States and Great Britain.

Fluctuation Dominated Josephson Tunneling with a Scanning Tunneling Microscope

International Nuclear Information System (INIS)

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

2001-01-01

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

Seat Belt Use Intention among Brazilian Undergraduate Students

OpenAIRE

TORQUATO, RENATA; FRANCO, CLÁUDIO M. A; BIANCHI, ALESSANDRA

2012-01-01

The objectives of this study were to explore self-reported seat belt use and group differences in different scenarios in a Brazilian sample and research the variables related to it. 120 college students answered a questionnaire with variables from the theory of planned behavior in order to evaluate the intention of seat belt use among car occupants. Results indicated that attitude and intention were the variables that most contributed to explaining seat belt use. Intention was highly correlat...

Asteroid Family Associations of Main-Belt Comets

Science.gov (United States)

Hsieh, Henry H.; Novakovic, Bojan; Kim, Yoonyoung; Brasser, Ramon

2016-10-01

We present a population-level analysis of the asteroid family associations of known main-belt comets or main-belt comet candidates (which, to date, have largely just been analyzed on individual bases as they have been discovered). In addition to family associations that have already been reported in the literature, we have identified dynamical relationships between 324P/La Sagra and the Alauda family, P/2015 X6 (PANSTARRS) and the Aeolia family, and P/2016 G1 (PANSTARRS) and the Adeona family. We will discuss the overall implications of these family associations, particularly as they pertain to the hypothesis that members of primitive asteroid family members may be more susceptible to producing observable sublimation-driven dust emission activity, and thus becoming main-belt comets. We will also discuss the significance of other dynamical and physical properties of a family or sub-family as they relate to the likelihood of that family containing one or more currently active main-belt comets.

The ISI Tunnel

Science.gov (United States)

1993-10-01

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

Resonant tunnel magnetoresistance in a double magnetic tunnel junction

KAUST Repository

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

2011-01-01

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

Energy-saving belt conveyors installed in Polish collieries

Directory of Open Access Journals (Sweden)

Jerzy ANTONIAK

2010-01-01

Full Text Available An important problem of reducing energy consumption and dioxide emissions in the stage of construction and operation of mine belt conveyors is connected with their broad use in the industry. However, this notion is related to a reduction of electric energy consumption for conveyor drive and for production of conveyor components and assemblies (belts, rollers, load-bearing structure etc.. An essential role is played by an increased life of belt conveyors assemblies and components, principally belts. A reduced electric energy consumption results in a decreased CO2 emissions, e.g. hard coal – fired power station issues 0.28 kg CO2 per production of 1 kWh, in to answer production of 1 t steel accounts for 3.2 t CO2 emissions. The subject-matter presented in the paper concerning energy-saving in the horizontally and inclined mine belt conveyors installed in a Polish colliery – Anna, Jankowice and Marcel, has a big economic significance and it is important from the point of view of environmental protection.

Report Tunneling Cost Reduction Study prepared for Fermilab

International Nuclear Information System (INIS)

Not Available

1999-01-01

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

Tunneling through landsliding zone; Jisuberi chitainai no tunnel seko

Energy Technology Data Exchange (ETDEWEB)

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

1994-08-01

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

Exploring the collisional evolution of the asteroid belt

Science.gov (United States)

Bottke, W.; Broz, M.; O'Brien, D.; Campo Bagatin, A.; Morbidelli, A.

2014-07-01

The asteroid belt is a remnant of planet-formation processes. By modeling its collisional and dynamical history, and linking the results to constraints, we can probe how the planets and small bodies formed and evolved. Some key model constraints are: (i) The wavy shape of the main-belt size distribution (SFD), with inflection points near 100-km, 10--20-km, 1 to a few km, and ˜0.1-km diameter; (ii) The number of asteroid families created by the catastrophic breakup of large asteroid bodies over the last ˜ 4 Gy, with the number of disrupted D > 100 km bodies as small as ˜20 or as large as 60; (iii) the flux of small asteroids derived from the main belt that have struck the Moon over the last 3.5 Ga --- crater SFDs on lunar terrains with known ages suggest the D 100 km bodies have been significantly battered, but only a fraction have been catastrophically disrupted. Conversely, most small asteroids today are byproducts of fragmentation events. These results are consistent with growing evidence that most of the prominent meteorite classes were produced by young asteroid families. The big question is how to use what we know to determine the main belt's original size and state. This work is ongoing, but dynamical models hint at many possibilities, including both the late arrival and late removal of material from the main belt. In addition, no model has yet properly accounted for the bombardment of the primordial main belt by leftover planetesimals in the terrestrial planet region. It is also possible to use additional constraints, such as the apparent paucity of Vesta-like or V-type objects in the outer main belt, to argue that the primordial main belt at best only 3--4 its current mass at its start. In our talk, we will review what is known, what has been predicted, and some intriguing directions for the future.

Development of the tunneling junction simulation environment for scanning tunneling microscope evaluation

International Nuclear Information System (INIS)

Gajewski, Krzysztof; Piasecki, Tomasz; Kopiec, Daniel; Gotszalk, Teodor

2017-01-01

Proper configuration of scanning tunneling microscope electronics plays an important role in the atomic scale resolution surface imaging. Device evaluation in the tunneling contact between scanning tip and sample may be prone to the surface quality or mechanical disturbances. Thus the use of tunneling junction simulator makes electronics testing more reliable and increases its repeatability. Here, we present the theoretical background enabling the proper selection of electronic components circuitry used as a tunneling junction simulator. We also show how to simulate mechanics related to the piezoelectric scanner, which is applied in real experiments. Practical use of the proposed simulator and its application in metrological characterization of the developed scanning tunneling microscope is also shown. (paper)

SMALL MAIN-BELT ASTEROID SPECTROSCOPIC SURVEY, PHASE II

Data.gov (United States)

National Aeronautics and Space Administration — This data set contains visible-wavelength (0.435-0.925 micron) spectra for 1341 main-belt asteroids observed during the second phase of the Small Main-belt Asteroid...

Continuing scearch for a new type charging belt

International Nuclear Information System (INIS)

Jones, N.L.

1995-01-01

The EN Tandem accelerator at Oak Ridge National Laboratory (ORNL) operates to support a varied program of atomic physics research. As such, the demands on the accelerator often require a range of operation from ∼0.38 to 7.0 MV on the terminal, with low ripple and long term steady state operation. The standard charging belts obtained from the manufacture have generally given acceptable performance, but it is reasonable that modem manufacturing techniques and materials could increase belt lifetimes and improve accelerator performance, particularly voltage ripple. A new belt of significantly different construction from that of the conventional belts was specified, purchased, and installed in 1993. After 2800 hours of use at voltages from 0.38 to 5.8 MV, it was removed from the accelerator in early August 1995

Enhanced spin Hall effect of tunneling light in hyperbolic metamaterial waveguide.

Science.gov (United States)

Tang, Tingting; Li, Chaoyang; Luo, Li

2016-08-01

Giant enhancement of spin Hall effect of tunneling light (SHETL) is theoretically proposed in a frustrated total internal reflection (FTIR) structure with hyperbolic metamaterial (HMM). We calculate the transverse shift of right-circularly polarized light in a SiO2-air-HMM-air-SiO2 waveguide and analyze the physical mechanism of the enhanced SHETL. The HMM anisotropy can greatly increase the transverse shift of polarized light even though HMM loss might reduce it. Compared with transverse shift of transmitted light through a single HMM slab with ZnAlO/ZnO multilayer, the maximum transverse shift of tunneling light through a FTIR structure with identical HMM can be significantly enlarged by more than three times which reaches -38 μm without any amplification method.

Fabrication of magnetic tunnel junctions with a single-crystalline LiF tunnel barrier

Science.gov (United States)

Krishna Narayananellore, Sai; Doko, Naoki; Matsuo, Norihiro; Saito, Hidekazu; Yuasa, Shinji

2018-04-01

We fabricated Fe/LiF/Fe magnetic tunnel junctions (MTJs) by molecular beam epitaxy on a MgO(001) substrate, where LiF is an insulating tunnel barrier with the same crystal structure as MgO (rock-salt type). Crystallographical studies such as transmission electron microscopy and nanobeam electron diffraction observations revealed that the LiF tunnel barrier is single-crystalline and has a LiF(001)[100] ∥ bottom Fe(001)[110] crystal orientation, which is constructed in the same manner as MgO(001) on Fe(001). Also, the in-plane lattice mismatch between the LiF tunnel barrier and the Fe bottom electrode was estimated to be small (about 0.5%). Despite such advantages for the tunnel barrier of the MTJ, the observed tunnel magnetoresistance (MR) ratio was low (˜6% at 20 K) and showed a significant decrease with increasing temperature (˜1% at room temperature). The results imply that indirect tunneling and/or thermally excited carriers in the LiF tunnel barrier, in which the current basically is not spin-polarized, play a major role in electrical transport in the MTJ.

Resonant tunneling via spin-polarized barrier states in a magnetic tunnel junction

NARCIS (Netherlands)

Jansen, R.; Lodder, J.C.

2000-01-01

Resonant tunneling through states in the barrier of a magnetic tunnel junction has been analyzed theoretically for the case of a spin-polarized density of barrier states. It is shown that for highly spin-polarized barrier states, the magnetoresistance due to resonant tunneling is enhanced compared

Quantum tunneling time

International Nuclear Information System (INIS)

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

2004-01-01

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

Transfer points of belt conveyors operating with unfavorable bulk

Energy Technology Data Exchange (ETDEWEB)

Goehring, H [Technische Universitaet, Dresden (German Democratic Republic)

1989-06-01

Describes design of belt conveyor chutes that transfer bulk of surface mines from one conveyor to another. Conveyor belt velocity is a significant parameter. Unfavorable chute design may lead to bulk flow congestion, bulk velocity losses etc. The bulk flow process is analyzed, bulk flow velocities, belt inclinations and bulk feeding from 2 conveyors into one chute are taken into account. Conventional chutes have parabolic belt impact walls. An improved version with divided impact walls is proposed that maintains a relatively high bulk velocity, reduces friction at chute walls and decreases wear and dirt build-up. Design of the improved chute is explained. It is built to adapt to existing structures without major modifications. The angle between 2 belt conveyors can be up to 90 degrees, the best bulk transfer is noted at conveyor angles below 60 degrees. Various graphs and schemes are provided. 6 refs.

Non-linear belt transient analysis. A hybrid model for numerical belt conveyor simulation

Energy Technology Data Exchange (ETDEWEB)

Harrison, A. [Scientific Solutions, Inc., Aurora, CO (United States)

2008-07-01

Frictional and rolling losses along a running conveyor are discussed due to their important influence on wave propagation during starting and stopping. Hybrid friction models allow belt rubber losses and material flexing to be included in the initial tension calculations prior to any dynamic analysis. Once running tensions are defined, a numerical integration method using non-linear stiffness gradients is used to generate transient forces during starting and stopping. A modified Euler integration technique is used to simulate the entire starting and stopping cycle in less than 0.1 seconds. The procedure enables a faster scrutiny of unforeseen conveyor design issues such as low belt tension zones and high forces at drives. (orig.)

Selection of Belt Conveyors Drive Units Number by Technical –Economical Analysis

OpenAIRE

Despodov, Zoran; Mijalkovski, Stojance; Adjiski, Vancho; Panov, Zoran

2014-01-01

In this paper is presented a methodology for selection of belt conveyor drive units number by technical - economical analysis of their parameters. Belt Conveyors with follow drive arrangement will be considered: one, two, three and four drive units. In the technical - economical analysis are including: Tension forces, Power of belt conveyor, Costs for belt, Costs for power and reducers, Total cost for belt conveyor system.

Green operations of belt conveyors by means of speed control

NARCIS (Netherlands)

He, D.; Pang, Y.; Lodewijks, G.

2017-01-01

Belt conveyors can be partially loaded due to the variation of bulk material flow loaded onto the conveyor. Speed control attempts to reduce the belt conveyor energy consumption and to enable the green operations of belt conveyors. Current research of speed control rarely takes the conveyor dynamics

Radiation belt seed population and its association with the relativistic electron dynamics: A statistical study: Radiation Belt Seed Population

International Nuclear Information System (INIS)

Tang, C. L.; Wang, Y. X.; Ni, B.; Zhang, J.-C.

2017-01-01

Using the Van Allen Probes data, we study the radiation belt seed population and it associated with the relativistic electron dynamics during 74 geomagnetic storm events. Based on the flux changes of 1 MeV electrons before and after the storm peak, these storm events are divided into two groups of “non-preconditioned” and “preconditioned”. The statistical study shows that the storm intensity is of significant importance for the distribution of the seed population (336 keV electrons) in the outer radiation belt. However, substorm intensity can also be important to the evolution of the seed population for some geomagnetic storm events. For non-preconditioned storm events, the correlation between the peak fluxes and their L-shell locations of the seed population and relativistic electrons (592 keV, 1.0 MeV, 1.8 MeV, and 2.1 MeV) is consistent with the energy-dependent dynamic processes in the outer radiation belt. For preconditioned storm events, the correlation between the features of the seed population and relativistic electrons is not fully consistent with the energy-dependent processes. It is suggested that the good correlation between the radiation belt seed population and ≤1.0 MeV electrons contributes to the prediction of the evolution of ≤1.0 MeV electrons in the Earth’s outer radiation belt during periods of geomagnetic storms.

MACRO MODEL OF SEAT BELT USE BY CAR DRIVERS AND PASSENGERS

Directory of Open Access Journals (Sweden)

Kazimierz JAMROZ

2013-12-01

Full Text Available The article presents some problems of seat belt use by car drivers and passengers. It looks in particular at seat belt use and effectiveness in selected countries. Next, factors of seat belt use are presented and methodology of model development. A macro model of seat belt use is presented based on data from around fifty countries from different continents.

Measuring fire size in tunnels

International Nuclear Information System (INIS)

Guo, Xiaoping; Zhang, Qihui

2013-01-01

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

Microwave-induced co-tunneling in single electron tunneling transistors

DEFF Research Database (Denmark)

Ejrnaes, M.; Savolainen, M.; Manscher, M.

2002-01-01

on rubber bellows. Cross-talk was minimized by using individual coaxial lines between the sample and the room temperature electronics: The co-tunneling experiments were performed at zero DC bias current by measuring the voltage response to a very small amplitude 2 Hz current modulation with the gate voltage......The influence of microwaves on the co-tunneling in single electron tunneling transistors has been investigated as function of frequency and power in the temperature range from 150 to 500 mK. All 20 low frequency connections and the RF line were filtered, and the whole cryostat was suspended...

High-energy outer radiation belt dynamic modeling

International Nuclear Information System (INIS)

Chiu, Y.T.; Nightingale, R.W.; Rinaldi, M.A.

1989-01-01

Specification of the average high-energy radiation belt environment in terms of phenomenological montages of satellite measurements has been available for some time. However, for many reasons both scientific and applicational (including concerns for a better understanding of the high-energy radiatino background in space), it is desirable to model the dynamic response of the high-energy radiation belts to sources, to losses, and to geomagnetic activity. Indeed, in the outer electron belt, this is the only mode of modeling that can handle the large intensity fluctuations. Anticipating the dynamic modeling objective of the upcoming Combined Release and Radiation Effects Satellite (CRRES) program, we have undertaken to initiate the study of the various essential elements in constructing a dynamic radiation belt model based on interpretation of satellite data according to simultaneous radial and pitch-angle diffusion theory. In order to prepare for the dynamic radiation belt modeling based on a large data set spanning a relatively large segment of L-values, such as required for CRRES, it is important to study a number of test cases with data of similar characteristics but more restricted in space-time coverage. In this way, models of increasing comprehensiveness can be built up from the experience of elucidating the dynamics of more restrictive data sets. The principal objectives of this paper are to discuss issues concerning dynamic modeling in general and to summarize in particular the good results of an initial attempt at constructing the dynamics of the outer electron radiation belt based on a moderately active data period from Lockheed's SC-3 instrument flown on board the SCATHA (P78-2) spacecraft. Further, we shall discuss the issues brought out and lessons learned in this test case

Great Lakes

Science.gov (United States)

Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

1998-01-01

The Great Lakes region, as defined here, includes the Great Lakes and their drainage basins in Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, and New York. The region also includes the portions of Minnesota, Wisconsin, and the 21 northernmost counties of Illinois that lie in the Mississippi River drainage basin, outside the floodplain of the river. The region spans about 9º of latitude and 20º of longitude and lies roughly halfway between the equator and the North Pole in a lowland corridor that extends from the Gulf of Mexico to the Arctic Ocean.The Great Lakes are the most prominent natural feature of the region (Fig. 1). They have a combined surface area of about 245,000 square kilometers and are among the largest, deepest lakes in the world. They are the largest single aggregation of fresh water on the planet (excluding the polar ice caps) and are the only glacial feature on Earth visible from the surface of the moon (The Nature Conservancy 1994a).The Great Lakes moderate the region’s climate, which presently ranges from subarctic in the north to humid continental warm in the south (Fig. 2), reflecting the movement of major weather masses from the north and south (U.S. Department of the Interior 1970; Eichenlaub 1979). The lakes act as heat sinks in summer and heat sources in winter and are major reservoirs that help humidify much of the region. They also create local precipitation belts in areas where air masses are pushed across the lakes by prevailing winds, pick up moisture from the lake surface, and then drop that moisture over land on the other side of the lake. The mean annual frost-free period—a general measure of the growing-season length for plants and some cold-blooded animals—varies from 60 days at higher elevations in the north to 160 days in lakeshore areas in the south. The climate influences the general distribution of wild plants and animals in the region and also influences the activities and distribution of the human

Influence of trap-assisted tunneling on trap-assisted tunneling current in double gate tunnel field-effect transistor

International Nuclear Information System (INIS)

Jiang Zhi; Zhuang Yi-Qi; Li Cong; Wang Ping; Liu Yu-Qi

2016-01-01

Trap-assisted tunneling (TAT) has attracted more and more attention, because it seriously affects the sub-threshold characteristic of tunnel field-effect transistor (TFET). In this paper, we assess subthreshold performance of double gate TFET (DG-TFET) through a band-to-band tunneling (BTBT) model, including phonon-assisted scattering and acoustic surface phonons scattering. Interface state density profile (D it ) and the trap level are included in the simulation to analyze their effects on TAT current and the mechanism of gate leakage current. (paper)

Bayesian inference of radiation belt loss timescales.

Science.gov (United States)

Camporeale, E.; Chandorkar, M.

2017-12-01

Electron fluxes in the Earth's radiation belts are routinely studied using the classical quasi-linear radial diffusion model. Although this simplified linear equation has proven to be an indispensable tool in understanding the dynamics of the radiation belt, it requires specification of quantities such as the diffusion coefficient and electron loss timescales that are never directly measured. Researchers have so far assumed a-priori parameterisations for radiation belt quantities and derived the best fit using satellite data. The state of the art in this domain lacks a coherent formulation of this problem in a probabilistic framework. We present some recent progress that we have made in performing Bayesian inference of radial diffusion parameters. We achieve this by making extensive use of the theory connecting Gaussian Processes and linear partial differential equations, and performing Markov Chain Monte Carlo sampling of radial diffusion parameters. These results are important for understanding the role and the propagation of uncertainties in radiation belt simulations and, eventually, for providing a probabilistic forecast of energetic electron fluxes in a Space Weather context.

The Usefulness of the Preoperative Magnetic Resonance Imaging Findings in the Evaluation of Tarsal Tunnel Syndrome

Energy Technology Data Exchange (ETDEWEB)

Jung, Hyun Jin; Lee, Sheen Woo; Jeong, Yu Mi; Choi, Hye Young; Kim, Hyung Sik [Dept. of Radiology, Gil Hospital, Gacheon University College of Medicine, Incheon (Korea, Republic of); Park, Hong Gi; Kwak, Ji Hoon [Dept. of Orthopedic Surgery, Gil Hospital, Gacheon University College of Medicine, Incheon (Korea, Republic of)

2012-02-15

The purpose of this study was to access the diverse conditions that lead to the clinical manifestations of tarsal tunnel syndrome and evaluate the usefulness of magnetic resonance imaging (MRI) in preoperative evaluation. Thirty-three patients who underwent ankle MRI and surgery under the impression of tarsal tunnel syndrome were retrospectively analyzed. The findings on ankle MRI were categorized into space occupying lesions within the tarsal tunnel, space occupying lesions of the tunnel wall, and non-space occupying lesions. Associated plantar muscle atrophy was also evaluated. Medical records were reviewed for correlation of nerve conduction velocity (NCV) and surgical findings. There were 21 space occupying lesions of the tarsal tunnel, and eight lesions of tarsal tunnel wall. There were three cases with accessory muscle, three with tarsal coalition, five with ganglion cysts, one neurogenic tumor, five flexor retinaculum hypertrophy, three varicose veins, and nine with tenosynovitis of the posterior tibialis, flexor digitorum longus, or flexor hallucis longus tendon. One patient was found to have a deltoid ligament sprain. Of the 32, eight patients experienced fatty atrophic change within any one of the foot muscles. NCV was positive in 79% of the MRI-positive lesions. MRI provides detailed information on ankle anatomy, which includes that of tarsal tunnel and beyond. Pathologic conditions that cause or mimic tarsal tunnel syndrome are well demonstrated. MRI can enhance surgical planning by indicating the extent of decompression required, and help with further patient management. Patients with tarsal tunnel syndrome can greatly benefit from preoperative MRI. However, it should be noted that not all cases with tarsal tunnel syndrome have MRI-demonstrable causes.

The Usefulness of the Preoperative Magnetic Resonance Imaging Findings in the Evaluation of Tarsal Tunnel Syndrome

International Nuclear Information System (INIS)

Jung, Hyun Jin; Lee, Sheen Woo; Jeong, Yu Mi; Choi, Hye Young; Kim, Hyung Sik; Park, Hong Gi; Kwak, Ji Hoon

2012-01-01

The purpose of this study was to access the diverse conditions that lead to the clinical manifestations of tarsal tunnel syndrome and evaluate the usefulness of magnetic resonance imaging (MRI) in preoperative evaluation. Thirty-three patients who underwent ankle MRI and surgery under the impression of tarsal tunnel syndrome were retrospectively analyzed. The findings on ankle MRI were categorized into space occupying lesions within the tarsal tunnel, space occupying lesions of the tunnel wall, and non-space occupying lesions. Associated plantar muscle atrophy was also evaluated. Medical records were reviewed for correlation of nerve conduction velocity (NCV) and surgical findings. There were 21 space occupying lesions of the tarsal tunnel, and eight lesions of tarsal tunnel wall. There were three cases with accessory muscle, three with tarsal coalition, five with ganglion cysts, one neurogenic tumor, five flexor retinaculum hypertrophy, three varicose veins, and nine with tenosynovitis of the posterior tibialis, flexor digitorum longus, or flexor hallucis longus tendon. One patient was found to have a deltoid ligament sprain. Of the 32, eight patients experienced fatty atrophic change within any one of the foot muscles. NCV was positive in 79% of the MRI-positive lesions. MRI provides detailed information on ankle anatomy, which includes that of tarsal tunnel and beyond. Pathologic conditions that cause or mimic tarsal tunnel syndrome are well demonstrated. MRI can enhance surgical planning by indicating the extent of decompression required, and help with further patient management. Patients with tarsal tunnel syndrome can greatly benefit from preoperative MRI. However, it should be noted that not all cases with tarsal tunnel syndrome have MRI-demonstrable causes.

Thermovoltages in vacuum tunneling investigated by scanning tunneling microscopy

OpenAIRE

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

1995-01-01

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

Belt conveyor dynamics in transient operation for speed control

OpenAIRE

He, D.; Pang, Y.; Lodewijks, G.

2016-01-01

Belt conveyors play an important role in continuous dry bulk material transport, especially at the mining industry. Speed control is expected to reduce the energy consumption of belt conveyors. Transient operation is the operation of increasing or decreasing conveyor speed for speed control. According to literature review, current research rarely takes the conveyor dynamics in transient operation into account. However, in belt conveyor speed control, the conveyor dynamic behaviors are signifi...

Pre-microscope tunnelling — Inspiration or constraint?

Science.gov (United States)

Walmsley, D. G.

1987-03-01

Before the microscope burst upon the scene, tunnelling had established for itself a substantial niche in the repertoire of the solid state physicist. Over a period of 20 years it has contributed importantly to our understanding of many systems. It elucidated the superconducting state, first by a direct display of the energy gap then by providing detailed information on the phonon spectra and electron-phonon coupling strength in junction electrodes. Its use as a phonon spectrometer was subsequently extended to semiconductors and to the oxides of insulating barriers. Eventually the vibrational spectra of monolayer organic and inorganic adsorbates became amenable with rich scientific rewards. In a few cases electronic transitions have been observed. Plasmon excitation by tunnelling electrons led to insights on the electron loss function in metals at visible frequencies and provided along the way an intriguing light emitting device. With the advent of the microscope it is now appropriate to enquire how much of this experience can profitably be carried over to the new environment. Are we constrained just to repeat the experiments in a new configuration? Happily no. The microscope offers us topographical and spectroscopic information of a new order. One might next ask how great is the contact between the two disciplines? We explore this question and seek to establish where the pre-microscope experience can be helpful in inspiring our use of this marvellous new facility that we know as the scanning tunnelling microscope.

Deconstructing the conveyor belt.

Science.gov (United States)

Lozier, M Susan

2010-06-18

For the past several decades, oceanographers have embraced the dominant paradigm that the ocean's meridional overturning circulation operates like a conveyor belt, transporting cold waters equatorward at depth and warm waters poleward at the surface. Within this paradigm, the conveyor, driven by changes in deepwater production at high latitudes, moves deep waters and their attendant properties continuously along western boundary currents and returns surface waters unimpeded to deepwater formation sites. A number of studies conducted over the past few years have challenged this paradigm by revealing the vital role of the ocean's eddy and wind fields in establishing the structure and variability of the ocean's overturning. Here, we review those studies and discuss how they have collectively changed our view of the simple conveyor-belt model.

Assessment of field-induced quantum confinement in heterogate germanium electron–hole bilayer tunnel field-effect transistor

International Nuclear Information System (INIS)

Padilla, J. L.; Alper, C.; Ionescu, A. M.; Gámiz, F.

2014-01-01

The analysis of quantum mechanical confinement in recent germanium electron–hole bilayer tunnel field-effect transistors has been shown to substantially affect the band-to-band tunneling (BTBT) mechanism between electron and hole inversion layers that constitutes the operating principle of these devices. The vertical electric field that appears across the intrinsic semiconductor to give rise to the bilayer configuration makes the formerly continuous conduction and valence bands become a discrete set of energy subbands, therefore increasing the effective bandgap close to the gates and reducing the BTBT probabilities. In this letter, we present a simulation approach that shows how the inclusion of quantum confinement and the subsequent modification of the band profile results in the appearance of lateral tunneling to the underlap regions that greatly degrades the subthreshold swing of these devices. To overcome this drawback imposed by confinement, we propose an heterogate configuration that proves to suppress this parasitic tunneling and enhances the device performance.

Assessment of field-induced quantum confinement in heterogate germanium electron–hole bilayer tunnel field-effect transistor

Energy Technology Data Exchange (ETDEWEB)

Padilla, J. L., E-mail: jose.padilladelatorre@epfl.ch; Alper, C.; Ionescu, A. M. [Nanoelectronic Devices Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015 (Switzerland); Gámiz, F. [Departamento de Electrónica y Tecnología de los Computadores, Universidad de Granada, Avda. Fuentenueva s/n, 18071 Granada (Spain)

2014-08-25

The analysis of quantum mechanical confinement in recent germanium electron–hole bilayer tunnel field-effect transistors has been shown to substantially affect the band-to-band tunneling (BTBT) mechanism between electron and hole inversion layers that constitutes the operating principle of these devices. The vertical electric field that appears across the intrinsic semiconductor to give rise to the bilayer configuration makes the formerly continuous conduction and valence bands become a discrete set of energy subbands, therefore increasing the effective bandgap close to the gates and reducing the BTBT probabilities. In this letter, we present a simulation approach that shows how the inclusion of quantum confinement and the subsequent modification of the band profile results in the appearance of lateral tunneling to the underlap regions that greatly degrades the subthreshold swing of these devices. To overcome this drawback imposed by confinement, we propose an heterogate configuration that proves to suppress this parasitic tunneling and enhances the device performance.

About tunnelling times

International Nuclear Information System (INIS)

Olkhovsky, V.S.; Recami, E.

1991-08-01

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

Design of belt conveyors in bulk terminal applications. Part II

Energy Technology Data Exchange (ETDEWEB)

Goodwin, P J; Ramos, C M

1986-04-01

The main design parameters used for belt conveyors in harbour applications are discussed. Conveyor belting including the carcass, belt cover, belt tension and speed, and safety factors, idlers, conveyor pulleys, motors, fluid couplings and drive arrangements are considered. Technical factors are briefly outlined for the designer to consider to achieve minimum acceptable component service life. A method is discussed to reduce coal degradation investigated using a test chute designed for the purpose of minimizing sized coal degradation at transfer points in the refurbishing of the Durban Coal Terminal. 24 references.

Health Monitoring for Coated Steel Belts in an Elevator System

Directory of Open Access Journals (Sweden)

Huaming Lei

2012-01-01

Full Text Available This paper presents a method of health monitoring for coated steel belts in an elevator system by measuring the electrical resistance of the ropes embedded in the belt. A model on resistance change caused by fretting wear and stress fatigue has been established. Temperature and reciprocating cycles are also taken into consideration when determining the potential strength degradation of the belts. It is proved by experiments that the method could effectively estimate the health degradation of the most dangerous section as well as other ones along the whole belts.

Tunneling current between graphene layers

OpenAIRE

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

2013-01-01

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

Single Electron Tunneling

International Nuclear Information System (INIS)

Ruggiero, Steven T.

2005-01-01

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

Drill and blast tunnelling; Konvensjonell drift av tunneler

Energy Technology Data Exchange (ETDEWEB)

Roenn, Paal-Egil

1997-12-31

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

Resonant tunnel magnetoresistance in double-barrier planar magnetic tunnel junctions

KAUST Repository

Useinov, A. N.

2011-08-24

We present a theoretical approach to calculate the spin-dependent current and tunnel magnetoresistance (TMR) in a double-barrier magnetic tunnel junction (DMTJ), in which the magnetization of the middle ferromagnetic metal layer can be aligned parallel or antiparallel in relation to the fixed magnetizations of the left and right ferromagnetic electrodes. The electron transport through the DMTJ is considered as a three-dimensional problem, taking into account all transmitting electron trajectories as well as the spin-dependent momentum conservation law. The dependence of the transmission coefficient and spin-polarized currents on the applied voltage is derived as an exact solution to the quantum-mechanical problem for the spin-polarized transport. In the range of the developed physical model, the resonant tunneling, nonresonant tunneling, and enhanced spin filtering can be explained; the simulation results are in good agreement with experimental data.

Resonant tunnel magnetoresistance in double-barrier planar magnetic tunnel junctions

KAUST Repository

Useinov, A. N.; Kosel, Jü rgen; Useinov, N. Kh.; Tagirov, L. R.

2011-01-01

We present a theoretical approach to calculate the spin-dependent current and tunnel magnetoresistance (TMR) in a double-barrier magnetic tunnel junction (DMTJ), in which the magnetization of the middle ferromagnetic metal layer can be aligned parallel or antiparallel in relation to the fixed magnetizations of the left and right ferromagnetic electrodes. The electron transport through the DMTJ is considered as a three-dimensional problem, taking into account all transmitting electron trajectories as well as the spin-dependent momentum conservation law. The dependence of the transmission coefficient and spin-polarized currents on the applied voltage is derived as an exact solution to the quantum-mechanical problem for the spin-polarized transport. In the range of the developed physical model, the resonant tunneling, nonresonant tunneling, and enhanced spin filtering can be explained; the simulation results are in good agreement with experimental data.

Development of Abdominal Compression Belt and Evaluation of the Efficiency for the Reduction of Respiratory Motion in SBRT

International Nuclear Information System (INIS)

Hwang, Seon Bung; Kim, Il Hwan; Kim, Woong; Im, Hyeong Seo; Gang, Jin Mook; Jeong, Seong Min; Kim, Gi Hwan; Lee, Ah Ram; Cho, Yura

2011-01-01

It's essential to minimize the tumor motion and identify the exact location of the lesions to achieve the improvement in radiation therapy efficiency during SBRT. In this study, we made the established compression belt to reduce respiratory motion and evaluated the usefulness of clinical application in SBRT. We analyzed the merits and demerits of the established compression belt to reduce the respiratory motion and improved the reproducibility and precision in use. To evaluate the usefulness of improved compression belt for respiratory motion reduction in SBRT, firstly, we reviewed the spiral CT images acquired in inspiration and expiration states of 8 lung cancer cases, respectively, and analyzed the three dimensional tumor motion related to respiration. To evaluate isodose distribution, secondly, we also made the special phantom using EBT2 film (Gafchronic, ISP, USA) and we prepared the robot (Cartesian Robot-2 Axis, FARARCM4H, Samsung Mechatronics, Korea) to reproduce three dimensional tumor motion. And analysis was made for isodose curves and two dimensional isodose profiles with reproducibility of respiratory motion on the basis of CT images. A respiratory motion reduction compression belt (Velcro type) that has convenient use and good reproducibility was developed. The moving differences of three dimensional tumor motion of lung cancer cases analyzed by CT images were mean 3.2 mm, 4.3 mm and 13 mm each in LR, AP and CC directions. The result of characteristic change in dose distribution using the phantom and rectangular coordinates robot showed that the distortion of isodose has great differences, mean length was 4.2 mm; the differences were 8.0% and 16.8% each for cranio-caudal and 8.1% and 10.9% each for left-right directions in underdose below the prescribed dose. In this study, we could develop the convenient and efficient compression belt that can make the organs' motion minimize. With this compression belt, we confirmed that underdose due to respiration

Development of Abdominal Compression Belt and Evaluation of the Efficiency for the Reduction of Respiratory Motion in SBRT

Energy Technology Data Exchange (ETDEWEB)

Hwang, Seon Bung; Kim, Il Hwan; Kim, Woong; Im, Hyeong Seo; Gang, Jin Mook; Jeong, Seong Min; Kim, Gi Hwan; Lee, Ah Ram [Dept. of Radiation and Oncology, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Cho, Yura [Dept. of Cyberknife, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2011-03-15

It's essential to minimize the tumor motion and identify the exact location of the lesions to achieve the improvement in radiation therapy efficiency during SBRT. In this study, we made the established compression belt to reduce respiratory motion and evaluated the usefulness of clinical application in SBRT. We analyzed the merits and demerits of the established compression belt to reduce the respiratory motion and improved the reproducibility and precision in use. To evaluate the usefulness of improved compression belt for respiratory motion reduction in SBRT, firstly, we reviewed the spiral CT images acquired in inspiration and expiration states of 8 lung cancer cases, respectively, and analyzed the three dimensional tumor motion related to respiration. To evaluate isodose distribution, secondly, we also made the special phantom using EBT2 film (Gafchronic, ISP, USA) and we prepared the robot (Cartesian Robot-2 Axis, FARARCM4H, Samsung Mechatronics, Korea) to reproduce three dimensional tumor motion. And analysis was made for isodose curves and two dimensional isodose profiles with reproducibility of respiratory motion on the basis of CT images. A respiratory motion reduction compression belt (Velcro type) that has convenient use and good reproducibility was developed. The moving differences of three dimensional tumor motion of lung cancer cases analyzed by CT images were mean 3.2 mm, 4.3 mm and 13 mm each in LR, AP and CC directions. The result of characteristic change in dose distribution using the phantom and rectangular coordinates robot showed that the distortion of isodose has great differences, mean length was 4.2 mm; the differences were 8.0% and 16.8% each for cranio-caudal and 8.1% and 10.9% each for left-right directions in underdose below the prescribed dose. In this study, we could develop the convenient and efficient compression belt that can make the organs' motion minimize. With this compression belt, we confirmed that underdose due to

Coal belt options

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-03-15

Whether moving coal long distances overland or short distances in-plant, belt conveyors will always be in demand. The article reports on recent systems developments and applications by Beumer, Horizon Conveyor Equipment, Conveyor Dynamics, Doppelmayr Transport Technology, Enclosed Bulk Systems, ContiTech and Bateman Engineered Technologies. 2 photos.

A Parametric Energy Model for Energy Management of Long Belt Conveyors

Directory of Open Access Journals (Sweden)

Tebello Mathaba

2015-12-01

Full Text Available As electricity prices continue to rise, the increasing need for energy management requires better understanding of models for energy-consuming applications, such as conveyor belts. Conveyor belts are used in a wide range of industries, including power generation, mining and mineral processing. Conveyor technological advances are leading to increasingly long conveyor belts being commissioned. Thus, the energy consumption of each individual belt conveyor unit is becoming increasingly significant. This paper proposes a generic energy model for belt conveyors with long troughed belts. The model has a two-parameter power equation, and it uses a partial differential equation to capture the variable amount of material mass per unit length throughout the belt length. Verification results show that the power consumption calculations of the newly proposed simpler model are consistent with those of a known non-linear model with an error of less than 4%. The online parameter identification set-up of the model is proposed. Simulations indicate that the parameters can be identified successfully from data with up to 15% measurement noise. Results show that the proposed model gives better predictions of the power consumed and material delivered by a long conveyor belt than the steady-state models in the current literature.

RATIONALE FOR CENTERING CAPACITY OF REDISIGNED BELT CONVEYOR DRUMS

Directory of Open Access Journals (Sweden)

V. V. Suglobov

2016-02-01

Full Text Available Purpose. In the study is necessary: 1 to justify aligning drums of a new design of belt conveyors; 2 to develop a method for calculating and determining the rational design parameters of drums depending on the technical parameters of the conveyor belt (the length of the conveyor, belt width, the performance of the conveyor, the diameter of the drive and tension drums, etc.; 3 to carry out pilot studies of efficiency conveyor belt in a production environment in order to determine the magnitude of dynamic loads and a comparative evaluation of the effectiveness of the centering ability of conventional and new designs of drums. Methodology. To substantiate the effectiveness of the centering ability of the drums of a new design by the authors developed a mathematical model of interaction of the tape with the drum. Mathematical simulation of tape reels with new design comes to drawing up a differential equation of the belt based on the dynamic component and restoring force. This model allowed us to estimate the movement of the tape in the transverse direction based on the calculated additional dynamic loads and forces on the investigated centering a conveyor belt with given specifications. For the first time the technique of calculating and determining the rational parameters of the drums, which allows determining the design parameters of the centering portions, depending on the mechanical properties and geometric parameters of the tape. Findings. With the help of mathematical modeling the scientifically substantiated effect of centering the ability of the new design of the drum, which ensures stable tape running along the longitudinal axis of the conveyor. The authors made the following conclusions: 1 the mathematical model of interaction with the new belt design of the drum, which allowed to describe the belt in the transverse direction in view of additional dynamic loads and renewable power was developed; 2 the method of calculation and

Plasmonic non-concentric nanorings array as an unidirectional nano-optical conveyor belt actuated by polarization rotation.

Science.gov (United States)

Jiang, Min; Wang, Guanghui; Jiao, Wenxiang; Ying, Zhoufeng; Zou, Ningmu; Ho, Ho-Pui; Sun, Tianyu; Zhang, Xuping

2017-01-15

We report a nano-optical conveyor belt containing an array of gold plasmonic non-concentric nanorings (PNNRs) for the realization of trapping and unidirectional transportation of nanoparticles through rotating the polarization of an excitation beam. The location of hot spots within an asymmetric plasmonic nanostructure is polarization dependent, thus making it possible to manipulate a trapped target by rotating the incident polarization state. In the case of PNNR, the two poles have highly unbalanced trap potential. This greatly enhances the chance of transferring trapped particles between adjacent PNNRs in a given direction through rotating the polarization. As confirmed by three-dimensional finite-difference time-domain analysis, an array of PNNRs forms an unidirectional nano-optical conveyor belt, which delivers target nanoparticles or biomolecules over a long distance with nanometer accuracy. With the capacity to trap and to transfer, our design offers a versatile scheme for conducting mechanical sample manipulation in many on-chip optofluidic applications.

Energy saving for belt conveyors by speed control

NARCIS (Netherlands)

He, D.

2017-01-01

Belt conveyors are widely used in bulk solids handling and conveying systems. Considering the extensive use of belt conveyors, their operations involve a large amount of energy. Taking the relevant economic and social challenges into account, there is a strong demand for lowering the energy

International Comparison of Water Resources Utilization Efficiency in the Silk Road Economic Belt

Science.gov (United States)

Yan, Long; Ma, Jing; Deng, Wei; Wang, Yong

2018-03-01

In order to get knowledge of the standard of water utilization of the Silk Road Economic Belt from international point of view, the paper analyzes the annual variation of water resources utilization in the Silk Road Economic Belt, and compares with other typical countries. The study shows that Water resources utilization efficiency has been greatly improved in recent 20 years and the water consumption per USD 10000 of GDP has been declined 87.97%. the improvement of industrial water consumption efficiency is the key driving factors for substantial decrease in water consumption.The comparison of water utilization and human development shows that the higher HDI the country is, the more efficient water utilization the country has. water consumption per USD 10000 of GDP in country with HDI>0.9 is 194m³, being 8.5% of that in country with HDI from 0.5 to 0.6. On the premise of maintaining the stable economic and social development of the Silk Road Economic Belt, the realization of the control target of total water consumption must depend on the strict control over the disorderly expansion of irrigated area, the change in the mode of economic growth, the implementation of the development strategy for new industrialization and urbanization, vigorous development of the processing industry with low water consumption as well as the high-tech and high value-added industry. Only in this way, the control target of total water consumption can be realized in the process of completing the industrialization task.

The Foundations of Radiation Belt Research

Science.gov (United States)

Ludwig, G. H.

2008-12-01

The United States undertook the launching of an artificial Earth satellite as part of its contribution to the International Geophysical Year. The Vanguard program was established to meet that commitment, and it developed a launch vehicle, ground station network, and suite of scientific payloads, including the cosmic ray experiment proposed by James A. Van Allen. Although Vanguard eventually exceeded all of its pre-stated goals, the preemptive launches of Sputniks I and II by the Soviets in October and November 1957 spurred the U.S. into a frenzy of activity, resulting in the launches of Explorers I and III in January and March of 1958. The data from those two satellites quickly revealed the lower boundary of an unexpected region of high intensity radiation trapped in the Earth's magnetic field. The original announcement in May 1958 stated that the radiation was probably composed of either protons or electrons, and that, if electrons, it was probably bremsstrahlung formed in the satellite shell. Immediately following that announcement, approval was received for what became Explorer IV, whose announced purpose was to follow up on the new discovery. Another reason for the satellite, unmentioned at the time, was its inclusion as a component of the highly classified Argos program, a covert military program to test whether the detonation of nuclear devices at high altitude would inject measurable numbers of charged particles into durable trajectories in the Earth's magnetic field. Our team at Iowa produced the satellites under the oversight of, and with assistance by, the Army Ballistic Missile Agency in Huntsville, and with the contributions of key hardware from several other government laboratories. The project was completed in the unbelievably short period of seventy-seven days from approval to launch. Launched into a higher-inclination orbit than the earlier Explorers, Explorer IV confirmed the discovery and greatly expanded our understanding of the natural

Angle stations in or for endless conveyor belts

Science.gov (United States)

Steel, Alan

1987-04-07

In an angle station for an endless conveyor belt, there are presented to each incoming run of the belt stationary curved guide members (18, 19) of the shape of a major segment of a right-circular cylinder and having in the part-cylindrical portion (16 or 17) thereof rectangular openings (15) arranged in parallel and helical paths and through which project small freely-rotatable rollers (14), the continuously-changing segments of the curved surfaces of which projecting through said openings (15) are in attitude to change the direction of travel of the belt (13) through 90.degree. during passage of the belt about the part-cylindrical portion (16 or 17) of the guide member (18 or 19). The rectangular openings (15) are arranged with their longer edges lengthwise of the diagonals representing the mean of the helix but with those of a plurality of the rows nearest to each end of the part-cylindrical portion (16 or 17) slightly out of axial symmetry with said diagonals, being slightly inclined in a direction about the intersections (40) of the diagonals of the main portion of the openings, to provide a "toe-in" attitude in relation to the line of run of the endless conveyor belt.

Oroclines - a century of discourse about curved mountain belts (Petrus Peregrinus Medal Lecture)

Science.gov (United States)

Van der Voo, Rob

2014-05-01

generally carried out in fold- and trust-belts, the allochthony of the rotated limbs of the thin-skinned belts implied transport above a basal décollement plane located in the upper crust. Some examples of these thin-skinned oroclines will be given. However, in recent years oroclines have also been proposed as resulting from buckling of ribbon continents (e.g., Panama; D'Entrecasteaux) with the noteworthy Great Alaskan Terrane Wreck, as discussed by Stephen Johnston of the University of Victoria, as prime example. And oroclines of truly continental dimensions have been presented on the basis of paleomagnetic and structural data in Hercynian Europe and Asia (the Kazakhstan and Mongol-Okhotsk oroclines). Because most of the fold- and trust-belt oroclines contain thick carbonate formations; paleomagnetists frequently find that these have been remagnetized in geological episodes that are coeval with mountain building nearby in time and space. A connection between remagnetization and clay diagenesis is a possibility that is currently being investigated. If this is shown to be the case, the last word on oroclines will not have been printed.

Seat-belt message and the law?

Science.gov (United States)

Sengupta, S K; Patil, N G; Law, G

1989-09-01

This paper attempts to draw together available information on the use of seat belts, one of the most important safety devices for a person in a car. Considering the high rate of mortality and morbidity due to road traffic accidents in Papua New Guinea the authors strongly feel that seat-belt usage should be made compulsory. When one looks at the history of the implementation of such a successful countermeasure in other countries it seems that legislation is the only answer.

Magnetic refrigeration apparatus with belt of ferro or paramagnetic material

Science.gov (United States)

Barclay, John A.; Stewart, Walter F.; Henke, Michael D.; Kalash, Kenneth E.

1987-01-01

A magnetic refrigerator operating in the 12 to 77K range utilizes a belt which carries ferromagnetic or paramagnetic material and which is disposed in a loop which passes through the center of a solenoidal magnet to achieve cooling. The magnetic material carried by the belt, which can be blocks in frames of a linked belt, can be a mixture of substances with different Curie temperatures arranged such that the Curie temperatures progressively increase from one edge of the belt to the other. This magnetic refrigerator can be used to cool and liquefy hydrogen or other fluids.

Influence of trap-assisted tunneling on trap-assisted tunneling current in double gate tunnel field-effect transistor

Science.gov (United States)

Zhi, Jiang; Yi-Qi, Zhuang; Cong, Li; Ping, Wang; Yu-Qi, Liu

2016-02-01

Trap-assisted tunneling (TAT) has attracted more and more attention, because it seriously affects the sub-threshold characteristic of tunnel field-effect transistor (TFET). In this paper, we assess subthreshold performance of double gate TFET (DG-TFET) through a band-to-band tunneling (BTBT) model, including phonon-assisted scattering and acoustic surface phonons scattering. Interface state density profile (Dit) and the trap level are included in the simulation to analyze their effects on TAT current and the mechanism of gate leakage current. Project supported by the National Natural Science Foundation of China (Grant Nos. 61574109 and 61204092).

Study of tunneling transport in Si-based tunnel field-effect transistors with ON current enhancement utilizing isoelectronic trap

Science.gov (United States)

Mori, Takahiro; Morita, Yukinori; Miyata, Noriyuki; Migita, Shinji; Fukuda, Koichi; Mizubayashi, Wataru; Masahara, Meishoku; Yasuda, Tetsuji; Ota, Hiroyuki

2015-02-01

The temperature dependence of the tunneling transport characteristics of Si diodes with an isoelectronic impurity has been investigated in order to clarify the mechanism of the ON-current enhancement in Si-based tunnel field-effect transistors (TFETs) utilizing an isoelectronic trap (IET). The Al-N complex impurity was utilized for IET formation. We observed three types of tunneling current components in the diodes: indirect band-to-band tunneling (BTBT), trap-assisted tunneling (TAT), and thermally inactive tunneling. The indirect BTBT and TAT current components can be distinguished with the plot described in this paper. The thermally inactive tunneling current probably originated from tunneling consisting of two paths: tunneling between the valence band and the IET trap and tunneling between the IET trap and the conduction band. The probability of thermally inactive tunneling with the Al-N IET state is higher than the others. Utilization of the thermally inactive tunneling current has a significant effect in enhancing the driving current of Si-based TFETs.

Electrical installations of the Channel tunnel; Installations electriques du Tunnel sous la Manche

Energy Technology Data Exchange (ETDEWEB)

Kersabiec, G. de [Eurotunnel, Folkestone (United Kingdom)

2002-08-01

Like an underground factory, the railway and auxiliary equipments of the Channel tunnel between France and UK, need a reliable and redundant power supply with a high quality maintenance. This article presents: the design criteria of the power distribution systems, the installation itself and the organisation of its exploitation: 1 - transportation system of the Channel tunnel (loads to supply, exploitation imperatives, fundamental criteria); 2 - external power sources (connection to the UK and French grids, values used by the national grids); 3 - exploitation criteria, tunnel design; 4 - description (main UK and French power stations, 25 kV traction network, 21 kV distribution network, tunnels, lighting in railway tunnels, supply of terminals, earthing network); 5 - exploitation; 6 - maintenance and quality. (J.S.)

Gan-Hang tectonic belt and its geologic significance

International Nuclear Information System (INIS)

Deng Jiarui; Zhang Zhiping.

1989-01-01

Gan-Hang tectonic belt is predominantly controlled by Gan-Hang fracture zone. It is mainly composed of Yongfeng-Zhuji downwarping zone, Gan-Hang volcanic activity structural belt and Gan-Hang red basin downfaulted zone. Gan-Hang fracture zone is derived from evolution and development of Shaoxing-Jiangshan deep fracture. It is mainly composed of three deep and large fracture and Fuzhou-Yongfeng large fracture. The fracture zone is a long active belt, but in each active period the geologic structural patterns intensity, depth and forming time were not same. Gan-Hang tectonic belt possesses obvious inheritance. It has always maintained the character of the relative depression or low land since the Caledonian movement. This specific structural environment is favourable for uranium mineralization. At any rate, the formation of this uranium minerogenetic zone has been experiencing a long and complicated processes which were closely associated with long activity of Gan-Hang fracture zone

Magmatic formations in the Okhotsk--Chukotka volcanogenic belt

Energy Technology Data Exchange (ETDEWEB)

Osipov, A.P.

1976-05-01

The relationship between the Okhotsk-Chukotka volcanogenic belt of Northeast USSR and the stage of evolution of magnetism and tectonic development of the region are examined. Recognizing the associations of effusive and intrusive rocks that are typical of the southern part of the volcanogenic belt and that are joined together by some characteristic features, a basic plan is presented for examination of the problem of magnetic formations. On the basis of the distinctive characteristics of epigeosynclinal tectonic development of the territory and the sequence of formation of the magmatic rocks within it, three main groups: volcanic, coleanoplutonic, and plutonic, can be distinguished; and a general scheme of development of these types in space and time within the volcanogenic belt can be developed. According to this scheme, four main stages can be recognized in the Mesozoic and Cenozoic magmatic evolution of the Okhotsk-Chukotka belt. This scheme of classification takes into consideration the factor of the structural development of this tectonomagmatic element.

Heavy-Atom Tunneling Calculations in Thirteen Organic Reactions: Tunneling Contributions are Substantial, and Bell's Formula Closely Approximates Multidimensional Tunneling at ≥250 K.

Science.gov (United States)

Doubleday, Charles; Armas, Randy; Walker, Dana; Cosgriff, Christopher V; Greer, Edyta M

2017-10-09

Multidimensional tunneling calculations are carried out for 13 reactions, to test the scope of heavy-atom tunneling in organic chemistry, and to check the accuracy of one-dimensional tunneling models. The reactions include pericyclic, cycloaromatization, radical cyclization and ring opening, and S N 2. When compared at the temperatures that give the same effective rate constant of 3×10 -5  s -1 , tunneling accounts for 25-95 % of the rate in 8 of the 13 reactions. Values of transmission coefficients predicted by Bell's formula, κ Bell  , agree well with multidimensional tunneling (canonical variational transition state theory with small curvature tunneling), κ SCT . Mean unsigned deviations of κ Bell vs. κ SCT are 0.08, 0.04, 0.02 at 250, 300 and 400 K. This suggests that κ Bell is a useful first choice for predicting transmission coefficients in heavy-atom tunnelling. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Based on Fuzzy Comprehensive Evaluation Method The Investment Risk Assessment of Chinese Enterprises in The Countries Along “The Belt and Road”

Science.gov (United States)

Chen, Yanyu; Chai, Huaqi; Huang, Yimiao

2018-01-01

“Belt and Road Forum for International Cooperation” held in Beijing in May this year. once again, “The Belt and Road” strategic initiative to the world, causing the world’s enthusiastic response. The core of the “One Belt, One Road” strategy initiative is to promote infrastructure construction and interconnection, dock national policies and development strategies, deepen pragmatic cooperation, promote coordinated and coordinated development and achieve common prosperity. With the “The Belt and Road” strategy in-depth, Chinese enterprises will go abroad, in the countries along the country to invest in more and more examples, accompanied by the increasing risk. Analysis of the failure of investment cases, we can easily find that this is the majority of enterprises overseas investment in the lack of careful assessment of risk and risk of foreign investment risk management has a great relationship. In this paper, the risk factors are used to identify the risk factors table, and the fuzzy comprehensive evaluation method is used to estimate the comprehensive risk value of many uncertain factors that cannot be determined by the overseas investment. The risk assessment system is constructed to help Chinese enterprises to follow the " Investment to avoid risks, improve the success rate.

Real-time vehicle matching for multi-camera tunnel surveillance

Science.gov (United States)

Jelača, Vedran; Niño Castañeda, Jorge Oswaldo; Frías-Velázquez, Andrés; Pižurica, Aleksandra; Philips, Wilfried

2011-03-01

Tracking multiple vehicles with multiple cameras is a challenging problem of great importance in tunnel surveillance. One of the main challenges is accurate vehicle matching across the cameras with non-overlapping fields of view. Since systems dedicated to this task can contain hundreds of cameras which observe dozens of vehicles each, for a real-time performance computational efficiency is essential. In this paper, we propose a low complexity, yet highly accurate method for vehicle matching using vehicle signatures composed of Radon transform like projection profiles of the vehicle image. The proposed signatures can be calculated by a simple scan-line algorithm, by the camera software itself and transmitted to the central server or to the other cameras in a smart camera environment. The amount of data is drastically reduced compared to the whole image, which relaxes the data link capacity requirements. Experiments on real vehicle images, extracted from video sequences recorded in a tunnel by two distant security cameras, validate our approach.

Dynamics of the earth's radiation belts and inner magnetosphere (geophysical monograph series)

CERN Document Server

2013-01-01

Dynamics of the Earth's Radiation Belts and Inner Magnetosphere draws together current knowledge of the radiation belts prior to the launch of Radiation Belt Storm Probes (RPSP) and other imminent space missions, making this volume timely and unique. The volume will serve as a useful benchmark at this exciting and pivotal period in radiation belt research in advance of the new discoveries that the RPSP mission will surely bring. Highlights include the following: a review of the current state of the art of radiation belt science; a complete and up-to-date account of the wave-particle interactions that control the dynamical acceleration and loss processes of particles in the Earth's radiation belts and inner magnetosphere; a discussion emphasizing the importance of the cross-energy coupling of the particle populations of the radiation belts, ring current, and plasmasphere in controlling the dynamics of the inner magnetosphe...

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

International Nuclear Information System (INIS)

Cleland, A.N.

1991-01-01

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

New Quality Standards of Testing Idlers for Highly Effective Belt Conveyors

Science.gov (United States)

Król, Robert; Gladysiewicz, Lech; Kaszuba, Damian; Kisielewski, Waldemar

2017-12-01

The paper presents result of research and analyses carried out into the belt conveyors idlers’ rotational resistance which is one of the key factor indicating the quality of idlers. Moreover, idlers’ rotational resistance is important factor in total resistance to motion of belt conveyor. The evaluation of the technical condition of belt conveyor idlers is carried out in accordance with actual national and international standards which determine the methodology of measurements and acceptable values of measured idlers’ parameters. Requirements defined by the standards, which determine the suitability of idlers to a specific application, despite the development of knowledge on idlers and quality of presently manufactured idlers maintain the same level of parameters values over long periods of time. Nowadays the need to implement new, efficient and economically justified solution for belt conveyor transportation systems characterized by long routes and energy-efficiency is often discussed as one of goals in belt conveyors’ future. One of the basic conditions for achieving this goal is to use only carefully selected idlers with low rotational resistance under the full range of operational loads and high durability. Due to this it is necessary to develop new guidelines for evaluation of the technical condition of belt conveyor idlers in accordance with actual standards and perfecting of existing and development of new methods of idlers testing. The changes in particular should concern updating of values of parameters used for evaluation of the technical condition of belt conveyor idlers in relation to belt conveyors’ operational challenges and growing demands in terms of belt conveyors’ energy efficiency.

The Stability of the Conveyor Belt Pontoon

Directory of Open Access Journals (Sweden)

Jiří PODEŠVA

2011-06-01

Full Text Available To lead the conveyor belt transport cross water area the pontoon are used to support the carrying structure of the belts. The accident can happen when the pontoon turnover. For this reason the pontoon stability is investigated. The stability is described by the Reed’s diagram. This can be constructed analytically or via numerical modeling. Both methods are described in the paper.

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

Science.gov (United States)

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

2005-06-21

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

Performance approximation of pick-to-belt orderpicking systems

NARCIS (Netherlands)

M.B.M. de Koster (René)

1994-01-01

textabstractIn this paper, an approximation method is discussed for the analysis of pick-to-belt orderpicking systems. The aim of the approximation method is to provide an instrument for obtaining rapid insight in the performance of designs of pick-to-belt orderpicking systems. It can be used to

Overland conveyors. Cable or trough belt for 100 km transport haulage

Energy Technology Data Exchange (ETDEWEB)

Maton, A.E. [Maton Engineering Pty. Ltd., Orange Grove, WA (Australia)

2009-07-01

With the advances in belt conveyor technology today systems of 100 kilometres length are increasingly being considered. This article provides a comparison of two concepts for a 100 kilometre system of five 20 kilometre flights based on trough belt and cable belt technology. (orig.)

Vacuum phonon tunneling.

Science.gov (United States)

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

2010-10-15

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

Breaking through the tranfer tunnel

CERN Document Server

Laurent Guiraud

2001-01-01

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

New Tunneling Features in Polar III-Nitride Resonant Tunneling Diodes

Directory of Open Access Journals (Sweden)

Jimy Encomendero

2017-10-01

Full Text Available For the past two decades, repeatable resonant tunneling transport of electrons in III-nitride double barrier heterostructures has remained elusive at room temperature. In this work we theoretically and experimentally study III-nitride double-barrier resonant tunneling diodes (RTDs, the quantum transport characteristics of which exhibit new features that are unexplainable using existing semiconductor theory. The repeatable and robust resonant transport in our devices enables us to track the origin of these features to the broken inversion symmetry in the uniaxial crystal structure, which generates built-in spontaneous and piezoelectric polarization fields. Resonant tunneling transport enabled by the ground state as well as by the first excited state is demonstrated for the first time over a wide temperature window in planar III-nitride RTDs. An analytical transport model for polar resonant tunneling heterostructures is introduced for the first time, showing a good quantitative agreement with experimental data. From this model we realize that tunneling transport is an extremely sensitive measure of the built-in polarization fields. Since such electric fields play a crucial role in the design of electronic and photonic devices, but are difficult to measure, our work provides a completely new method to accurately determine their magnitude for the entire class of polar heterostructures.

Theoretical consideration of spin-polarized resonant tunneling in magnetic tunnel junctions

International Nuclear Information System (INIS)

Mu Haifeng; Zhu Zhengang; Zheng Qingrong; Jin Biao; Wang Zhengchuan; Su Gang

2004-01-01

A recent elegant experimental realization [S. Yuasa et al., Science 297 (2002) 234] of the spin-polarized resonant tunneling in magnetic tunnel junctions is interpreted in terms of a two-band model. It is shown that the tunnel magnetoresistance (TMR) decays oscillatorily with the thickness of the normal metal (NM) layer, being fairly in agreement with the experimental observation. The tunnel conductance is found to decay with slight oscillations with the increase of the NM layer thickness, which is also well consistent with the experiment. In addition, when the magnetizations of both ferromagnet electrodes are not collinearly aligned, TMR is found to exhibit sharp resonant peaks at some particular thickness of the NM layer. The peaked TMR obeys nicely a Gaussian distribution against the relative orientation of the magnetizations

Histological Observation of Regions around Bone Tunnels after Compression of the Bone Tunnel Wall in Ligament Reconstruction

International Nuclear Information System (INIS)

Maeda, Shintaro; Ishikawa, Hiroki; Tanigawa, Naoaki; Miyazaki, Kyosuke; Shioda, Seiji

2012-01-01

The objectives of this study were to investigate the time-course of influence of compression of bone tunnel wall in ligament reconstruction on tissue around the bone tunnel and to histologically examine the mechanism of preventing the complication of bone tunnel dilation, using rabbit tibia. A model in which the femoral origin of the extensor digitorum longus tendon was cut and inserted into a bone tunnel made proximal to the tibia was prepared in the bilateral hind legs of 20 Japanese white rabbits. In each animal, a tunnel was made using a drill only in the right leg, while an undersized bone tunnel was made by drilling and then dilated by compression using a dilator to the same tunnel size as that in the right leg. Animals were sacrificed at 0, 2, 4, 8 and 12 weeks after surgery (4 animals at each time point). Observation of bone tunnels by X-ray radiography showed osteosclerosis in the 2- and 4-week dilation groups. Osteosclerosis appeared as white lines around the bone tunnel on X-ray radiography. This suggests that dilation promotes callus formation in the bone tunnel wall and prevents the complication of bone tunnel enlargement after ligament reconstruction

27 June 2012 - Ambassador K. Pierce, Permanent Representative of the United Kingdom of Great Britain and Northern Ireland to the United Nations Office and other international organisations in Geneva visiting the LHC tunnel at Point 5 with Department Head P. Collier and CMS control room with Former Collaboration Spokesperson J. Virdee.

CERN Multimedia

Laurent Egli

2012-01-01

27 June 2012 - Ambassador K. Pierce, Permanent Representative of the United Kingdom of Great Britain and Northern Ireland to the United Nations Office and other international organisations in Geneva visiting the LHC tunnel at Point 5 with Department Head P. Collier and CMS control room with Former Collaboration Spokesperson J. Virdee.

Tunnel fire testing and modeling the Morgex North tunnel experiment

CERN Document Server

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

2017-01-01

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

Optimization of a tunneling barrier in magnetic tunneling junction by tilted-plasma oxidation

International Nuclear Information System (INIS)

Nam, C.H.; Shim, Heejae; Kim, K.S.; Cho, B.K.

2004-01-01

Oxidation of an AlO x insulating barrier in a magnetic tunneling junction (MTJ) was carried out by a tilted-plasma oxidation method. It was found that the tilted-plasma oxidation induced a gradual change in the extent of oxidation of an insulating layer, which consequently led to a gradual change in the tunneling magnetoresistance (TMR) and specific junction resistance (RA) of the MTJ. We found a linear relation in the TMR versus RA curve with positive and negative slopes for less- and overoxidized junctions, respectively, and a parabolic relation for optimally oxidized junctions. The crossover in the TMR versus RA curves provides an effective and useful way to optimize (and monitor) the oxidation condition of a tunneling barrier in MTJs especially of a tunneling barrier less than 10 A thick. The tunneling junctions were also investigated after thermal annealing at various temperatures. The observations after thermal annealing were found to be consistent with transmission electrons microscopy images and a scenario of the partial formation of an additional ultrathin tunneling barrier at the top surface of the bottom magnetic layer

Photon-assisted tunneling in a Fe-8 single-molecule magnet

OpenAIRE

Sorace, L.; Wernsdorfer, W.; Thirion, C.; Barra, A. L.; Pacchioni, M.; Mailly, D.; Barbara, B.

2003-01-01

The low temperature spin dynamics of a Fe8 Single-Molecule Magnet was studied under circularly polarized electromagnetic radiation allowing us to establish clearly photon-assisted tunneling. This effect, while linear at low power, becomes highly non-linear above a relatively low power threshold. This non-linearity is attributed to the nature of the coupling of the sample to the thermostat.These results are of great importance if such systems are to be used as quantum computers.

Belt Conveyor Dynamic Characteristics and Influential Factors

OpenAIRE

Li, Junxia; Pang, Xiaoxu

2018-01-01

This paper uses the Kelvin-Voigt viscoelastic model to establish the continuous dynamic equations for tail hammer tension belt conveyors. The viscoelastic continuity equations are solved using the generalized coordinate method. We analyze various factors influencing longitudinal vibration of the belt conveyor by simulation and propose a control strategy to limit the vibration. The proposed approach and control strategy were verified by several experimental researches and cases. The proposed a...

Quantum mechanical tunneling in chemical physics

CERN Document Server

Nakamura, Hiroki

2016-01-01

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

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

OpenAIRE

Filippone, Michele; Brouwer, Piet

2016-01-01

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

30 CFR 14.22 - Test for flame resistance of conveyor belts.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Test for flame resistance of conveyor belts. 14..., EVALUATION, AND APPROVAL OF MINING PRODUCTS REQUIREMENTS FOR THE APPROVAL OF FLAME-RESISTANT CONVEYOR BELTS Technical Requirements § 14.22 Test for flame resistance of conveyor belts. (a) Test procedures. The test...

Application fo tunneling and atomic force detection to machines and scientific instruments. Tunnel gensho ya genshikan no mechatronics eno oyo

Energy Technology Data Exchange (ETDEWEB)

Kawakatsu, H. (The University of Tokyo, Tokyo (Japan). Institute of Industrial Science)

1991-11-01

It is now about ten years since the scanning tunnel microscope (STM) and the atomic force microscope (AFM) were invented. These microscopes are used very importantly today as a surface analyzer capable of atomic order analysis for their very high resolution. The STM and AFM obtain images of atomic orders by means of mechanical scanning of the probes. This means that the microscopes can control positioning, force detection and displacement in regions of sub-nanometer orders. Examples of researches may include detection of acceleration, length measurement, positioning, force detection, nano-tripology, processing and gravitational wave detection. As described above, this paper notes the researches derived from the operational principles of the STM and AFM, rather than the researches on the observation objects. The great diversity of the researches taken up and the greatness in the number of researches in the STM and AFM gather how superbly germinative these were. 34 refs.

Dioxin emission factors for automobiles from tunnel air sampling in Northern Taiwan.

Science.gov (United States)

Chang, Moo Been; Chang, Shu Hao; Chen, Yuan Wu; Hsu, Hsuan Chien

2004-06-05

This study measured PCDD/F concentrations in tunnel air and vehicle exhaust. The ambient air samples were collected with air samplers (Tisch PS-1) complying with USEPA TO-9A. The results indicate that the tunnel air had a PCDD/F TEQ concentration about two times as high as that of outside air (47.3 and 57.1 fg-I-TEQ/m3 for tunnel air vs. 37.1 fg-I-TEQ/m3 and 23.3 fg-I-TEQ/m3 for outside air, respectively). This provides the direct evidence that PCDD/F compounds are emitted from the combustion processes in gasoline- and diesel-fueled engines. According to the tunnel study, the emission factors ranged from 5.83 to 59.2 pg I-TEQ/km for gasoline vehicles and 23.32 to 236.65 pg I-TEQ/km of diesel vehicles. This indicates that the dioxin emission factor in Taiwan is lower than that measured in USA, Norway and Germany. When the speed of the diesel vehicle was set at 40 km/h, the dioxin concentration emitted from diesel vehicle was 278 pg/m3 (6.27 pg-I-TEQ/m3) from tailpipe testing. However, when the diesel vehicle was idled, the dioxin concentration increased greatly to 4078 pg/m3 (41.9 pg-I-TEQ/m3). From the results of tunnel air sampling, the PCDD/Fs emission from automobiles in Taiwan was estimated as 3.69 g I-TEQ per year. Copryright 2003 Elsevier B.V.

A GREAT search for Deuterium in Comets

Science.gov (United States)

Mumma, Michael

2013-10-01

Comets are understood to be the most pristine bodies in the Solar System. Their compositions reflect the chemical state of materials at the very earliest evolutionary stages of the protosolar nebula and, as such, they provide detailed insight into the physical and chemical processes operating in planet-forming disks. Isotopic fractionation ratios of the molecular ices in the nucleus are regarded as signatures of formation processes. These ratios provide unique information on the natal heritage of those ices, and can also test the proposal that Earth's water and other volatiles were delivered by cometary bombardment. Measurement of deuterium fractionation ratios is thus a major goal in contemporary cometary science and the D/H ratio of water - the dominant volatile in comets - holds great promise for testing the formation history of cometary matter. The D/H ratio in cometary water has been measured in only eight comets. Seven were from the Oort Cloud reservoir and the D/H ratio was about twice that of the Earth's oceans. However, the recent Herschel measurement of HDO/H2O in 103P/Hartley-2 (the first from the Kuiper Belt) was consistent with exogenous delivery of Earth's water by comets. Outstanding questions remain: are cometary HDO/H2O ratios consistent with current theories of nebular chemical evolution or with an interstellar origin? Does the HDO/H2O ratio vary substantially among comet populations? Hartley-2 is the only Kuiper Belt comet with measured HDO/H2O, are there comets with similar ratios in the Oort cloud? These questions can only be addressed by measuring HDO/H2O ratios in many more suitable bright comets. We therefore propose to measure the D/H ratio in water in a suitable target-of-opportunity comet by performing observations of HDO and OH with the GREAT spectrometer on SOFIA. A multi-wavelength, ground-based observing campaign will also be conducted in support of the airborne observations.

Tunnelling of a molecule

International Nuclear Information System (INIS)

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

1998-01-01

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

The thrust belts of Western North America

Energy Technology Data Exchange (ETDEWEB)

Moulton, F.C.

1993-08-01

Most of the Basin and Range physiographic province of western North America is now believed to be part of the overthrust. The more obvious overthrust belt along the eastern edge of the Basin and Range Province is named the Sevier orogenic belt, where older rocks are observed thrust onto younger rocks. More detailed surface geological mapping, plus deep multiple-fold geophysical work and many oil and gas wildcat wells, have confirmed an east-vergent shortened and stacked sequence is present in many places in the Basin and Range. This western compressive deformed area in east central Nevada is now named the Elko orogenic belt by the U.S. Geological Survey. This older compressed Elko orogenic belt started forming approximately 250 m.y. ago when the North American plate started to move west as the Pangaea supercontinent started to fragment. The North American plate moved west under the sediments of the Miogeocline that were also moving west. Surface-formed highlands and oceanic island arcs on the west edge of the North American plate restricted the westward movement of the sediments in the Miogeocline, causing east-vergent ramp thrusts to form above the westward-moving North American plate. The flat, eastward-up-cutting thrust assemblages moved on the detachment surfaces.

SLH Timing Belt Powertrain

Energy Technology Data Exchange (ETDEWEB)

Schneider, Abe

2014-04-09

The main goal of this proposal was to develop and test a novel powertrain solution for the SLH hydroEngine, a low-cost, efficient low-head hydropower technology. Nearly two-thirds of U.S. renewable electricity is produced by hydropower (EIA 2010). According to the U.S. Department of Energy; this amount could be increased by 50% with small hydropower plants, often using already-existing dams (Hall 2004). There are more than 80,000 existing dams, and of these, less than 4% generate power (Blankinship 2009). In addition, there are over 800 irrigation districts in the U.S., many with multiple, non-power, low-head drops. These existing, non-power dams and irrigation drops could be retrofitted to produce distributed, baseload, renewable energy with appropriate technology. The problem is that most existing dams are low-head, or less than 30 feet in height (Ragon 2009). Only about 2% of the available low-head hydropower resource in the U.S. has been developed, leaving more than 70 GW of annual mean potential low-head capacity untapped (Hall 2004). Natel Energy, Inc. is developing a low-head hydropower turbine that operates efficiently at heads less than 6 meters and is cost-effective for deployment across multiple low-head structures. Because of the unique racetrack-like path taken by the prime-movers in the SLH, a flexible powertrain is required. Historically, the only viable technological solution was roller chain. Despite the having the ability to easily attach blades, roller chain is characterized by significant drawbacks, including high cost, wear, and vibration from chordal action. Advanced carbon- fiber-reinforced timing belts have been recently developed which, coupled with a novel belt attachment system developed by Natel Energy, result in a large reduction in moving parts, reduced mass and cost, and elimination of chordal action for increased fatigue life. The work done in this project affirmatively addressed each of the following 3 major uncertainties concerning

Influence of quasiparticle multi-tunneling on the energy flow through the superconducting tunnel junction

International Nuclear Information System (INIS)

Samedov, V. V.; Tulinov, B. M.

2011-01-01

Superconducting tunnel junction (STJ) detector consists of two layers of superconducting material separated by thin insulating barrier. An incident particle produces in superconductor excess nonequilibrium quasiparticles. Each quasiparticle in superconductor should be considered as quantum superposition of electron-like and hole-like excitations. This duality nature of quasiparticle leads to the effect of multi-tunneling. Quasiparticle starts to tunnel back and forth through the insulating barrier. After tunneling from biased electrode quasiparticle loses its energy via phonon emission. Eventually, the energy that equals to the difference in quasiparticle energy between two electrodes is deposited in the signal electrode. Because of the process of multi-tunneling, one quasiparticle can deposit energy more than once. In this work, the theory of branching cascade processes was applied to the process of energy deposition caused by the quasiparticle multi-tunneling. The formulae for the mean value and variance of the energy transferred by one quasiparticle into heat were derived. (authors)

Security Belt for Wireless Implantable Medical Devices.

Science.gov (United States)

Kulaç, Selman

2017-09-19

In this study, a new protective design compatible with existing non-secure systems was proposed, since it is focused on the secure communication of wireless IMD systems in all transmissions. This new protector is an external wearable device and appears to be a belt fitted around for the patients IMD implanted. However, in order to provide effective full duplex transmissions and physical layer security, some sophisticated transceiver antennas have been placed on the belt. In this approach, beam-focused multi-antennas in optimal positions on the belt are randomly switched when transmissions to the IMD are performed and multi-jammer switching with MRC combining or majority-rule based receiving techniques are applied when transmissions from the IMD are carried out. This approach can also reduce the power consumption of the IMDs and contribute to the prolongation of the IMD's battery life.

The use of seat belts and contributing factors : an international comparison.

NARCIS (Netherlands)

Mäkinen, T. Wittink, R.D. & Hagenzieker, M.P.

1991-01-01

The purpose of this study was to define factors that contribute to the use or non-use of seat belts. Legislation prescribing compulsory seat belt usage is one of the most important factors. Promotion of the use of seat belts without this legislation is very difficult and time-consuming. So far, the

Enhanced MRI in carpal tunnel syndrome

International Nuclear Information System (INIS)

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

1998-01-01

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

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

NARCIS (Netherlands)

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

2005-01-01

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

Control of tunneling in heterostructures

International Nuclear Information System (INIS)

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

2007-01-01

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

The evolution of Saturn's radiation belts modulated by changes in radial diffusion

Science.gov (United States)

Kollmann, P.; Roussos, E.; Kotova, A.; Paranicas, C.; Krupp, N.

2017-12-01

Globally magnetized planets, such as the Earth1 and Saturn2, are surrounded by radiation belts of protons and electrons with kinetic energies well into the million electronvolt range. The Earth's proton belt is supplied locally from galactic cosmic rays interacting with the atmosphere3, as well as from slow inward radial transport4. Its intensity shows a relationship with the solar cycle4,5 and abrupt dropouts due to geomagnetic storms6,7. Saturn's proton belts are simpler than the Earth's because cosmic rays are the principal source of energetic protons8 with virtually no contribution from inward transport, and these belts can therefore act as a prototype to understand more complex radiation belts. However, the time dependence of Saturn's proton belts had not been observed over sufficiently long timescales to test the driving mechanisms unambiguously. Here we analyse the evolution of Saturn's proton belts over a solar cycle using in-situ measurements from the Cassini Saturn orbiter and a numerical model. We find that the intensity in Saturn's proton radiation belts usually rises over time, interrupted by periods that last over a year for which the intensity is gradually dropping. These observations are inconsistent with predictions based on a modulation in the cosmic-ray source, as could be expected4,9 based on the evolution of the Earth's proton belts. We demonstrate that Saturn's intensity dropouts result instead from losses due to abrupt changes in magnetospheric radial diffusion.

Deformation and kinematics of the central Kirthar Fold Belt, Pakistan

Science.gov (United States)

Hinsch, Ralph; Hagedorn, Peter; Asmar, Chloé; Nasim, Muhammad; Aamir Rasheed, Muhammad; Kiely, James M.

2017-04-01

The Kirthar Fold Belt is part of the lateral mountain belts in Pakistan linking the Himalaya orogeny with the Makran accretionary wedge. This region is deforming very oblique/nearly parallel to the regional plate motion vector. The study area is situated between the prominent Chaman strike-slip fault in the West and the un-deformed foreland (Kirthar Foredeep/Middle Indus Basin) in the East. The Kirthar Fold Belt is subdivided into several crustal blocks/units based on structural orientation and deformation style (e.g. Kallat, Khuzdar, frontal Kirthar). This study uses newly acquired and depth-migrated 2D seismic lines, surface geology observations and Google Earth assessments to construct three balanced cross sections for the frontal part of the fold belt. Further work was done in order to insure the coherency of the built cross-sections by taking a closer look at the regional context inferred from published data, simple analogue modelling, and constructed regional sketch sections. The Khuzdar area and the frontal Kirthar Fold Belt are dominated by folding. Large thrusts with major stratigraphic repetitions are not observed. Furthermore, strike-slip faults in the Khuzdar area are scarce and not observed in the frontal Kirthar Fold Belt. The regional structural elevation rises from the foreland across the Kirthar Fold Belt towards the hinterland (Khuzdar area). These observations indicate that basement-involved deformation is present at depth. The domination of folding indicates a weak decollement below the folds (soft-linked deformation). The fold pattern in the Khuzdar area is complex, whereas the large folds of the central Kirthar Fold Belt trend SSW-NNE to N-S and are best described as large detachment folds that have been slightly uplifted by basement involved transpressive deformation underneath. Towards the foreland, the deformation is apparently more hard-linked and involves fault-propagation folding and a small triangle zone in Cretaceous sediments

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

NARCIS (Netherlands)

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

2013-01-01

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

Seismic prediction ahead of tunnel constructions

Science.gov (United States)

Jetschny, S.; Bohlen, T.; Nil, D. D.; Giese, R.

2007-12-01

To increase safety and efficiency of tunnel constructions, online seismic exploration ahead of a tunnel can become a valuable tool. Within the \\it OnSite project founded by the BMBF (German Ministry of Education and Research) within \\it GeoTechnologien a new forward looking seismic imaging technique is developed to e.g. determine weak and water bearing zones ahead of the constructions. Our approach is based on the excitation and registration of \\it tunnel surface waves. These waves are excited at the tunnel face behind the cutter head of a tunnel boring machine and travel into drilling direction. Arriving at the front face they generate body waves (mainly S-waves) propagating further ahead. Reflected S-waves are back- converted into tunnel surface waves. For a theoretical description of the conversion process and for finding optimal acquisition geometries it is of importance to study the propagation characteristics of tunnel surface waves. 3D seismic finite difference modeling and analytic solutions of the wave equation in cylindric coordinates revealed that at higher frequencies, i.e. if the tunnel diameter is significantly larger than the wavelength of S-waves, these surface waves can be regarded as Rayleigh-waves circulating the tunnel. For smaller frequencies, i.e. when the S-wavelength approaches the tunnel diameter, the propagation characteristics of these surface waves are then similar to S- waves. Field measurements performed by the GeoForschungsZentrum Potsdam, Germany at the Gotthard Base Tunnel (Switzerland) show both effects, i.e. the propagation of Rayleigh- and body-wave like waves along the tunnel. To enhance our understanding of the excitation and propagation characteristics of tunnel surface waves the transition of Rayleigh to tube-waves waves is investigated both analytically and by numerical simulations.

Geological characteristics of dike-structural belt in Taoshan orefield and its relationship to uranium deposits

International Nuclear Information System (INIS)

Zhang Wanliang; Zou Maoqing; Shao Fei; Nie Bin

2009-01-01

Taoshan uranium field is occurred in the Taoshan composite batholith in the central Jiangxi Province. The main body of the batholith was formed in Triassic-Early Cretaceous. In Late Cretaceous-Eogene, NE strike fault structure and dike belt were developed in the batholith. From the north to the south, there are successive Xiaobu-Matian dike-structural belt, Wangnitian dike- structural belt, Huangtan-Yueyuan dike-structural belt, Xibei-Shangluo dike-structural belt, Jipoling dike-structural belt, Wangce dike-structural belt and Shiyuanling dike-structural belt. These belts are controlled by the main fault, share the same space and similar time with the uranium mineralization, which is one of the important factors in positioning the uranium ore as well as the prospecting direction of exploration. (authors)

Belt conveyor dynamics in transient operation for speed control

NARCIS (Netherlands)

He, D.; Pang, Y.; Lodewijks, G.

2016-01-01

Belt conveyors play an important role in continuous dry bulk material transport, especially at the mining industry. Speed control is expected to reduce the energy consumption of belt conveyors. Transient operation is the operation of increasing or decreasing conveyor speed for speed control.

Gap anisotropy and tunneling currents. [MPS3

DEFF Research Database (Denmark)

Lazarides, N.; Sørensen, Mads Peter

1996-01-01

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

SEAT BELT USE AMONG CAR USERS IN MALAYSIA

Directory of Open Access Journals (Sweden)

S. KULANTHAYAN

2004-01-01

Full Text Available The car is the second (40% most common mode of transportation in Malaysia. In terms of fatal road accidents, car drivers constitute about 9.0% and passengers 13.6% of fatalities. The major cause of car occupants' fatality in such accidents is head injuries, which consist of more than half (56.4% of the fatalities. Thus restraining the head and body, the initial position is the most important injury control strategy for car users. The use of seat belts was deemed one of the most effective ways to reduce road accident fatalities in Malaysia and consequently the mandatory seat belt law was enforced in the early seventies. Therefore, a study on factors influencing the compliance behaviour of seat belt use among cars is needed as to date no such research has been undertaken in Malaysia. A questionnaire study was carried out in Selangor, Malaysia on the compliance behaviour of car occupants in relation to seat belt use. A total of 237 respondents were interviewed and the data analysed using logistic regression method. Six variables were found to be significant at 5 percent level (p<0.05: seating position, location of travel, education level, speeding, night-time driving and enforcement. Compliance with the seat belt law was higher among drivers, educated car users, in the presence of enforcement activities, travelling in city-center areas and car users with a positive attitude towards the risks of speeding and night driving.

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

Directory of Open Access Journals (Sweden)

Mingjiang Deng

2018-02-01

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

Magnetic Fluxtube Tunneling

Science.gov (United States)

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

1996-01-01

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

The tunnel magnetoresistance in chains of quantum dots weakly coupled to external leads

International Nuclear Information System (INIS)

Weymann, Ireneusz

2010-01-01

We analyze numerically the spin-dependent transport through coherent chains of three coupled quantum dots weakly connected to external magnetic leads. In particular, using the diagrammatic technique on the Keldysh contour, we calculate the conductance, shot noise and tunnel magnetoresistance (TMR) in the sequential and cotunneling regimes. We show that transport characteristics greatly depend on the strength of the interdot Coulomb correlations, which determines the spatial distribution of the electron wavefunction in the chain. When the correlations are relatively strong, depending on the transport regime, we find both negative TMR as well as TMR enhanced above the Julliere value, accompanied with negative differential conductance (NDC) and super-Poissonian shot noise. This nontrivial behavior of tunnel magnetoresistance is associated with selection rules that govern tunneling processes and various high-spin states of the chain that are relevant for transport. For weak interdot correlations, on the other hand, the TMR is always positive and not larger than the Julliere TMR, although super-Poissonian shot noise and NDC can still be observed.

Dark nebulae, dark lanes, and dust belts

CERN Document Server

Cooke, Antony

2012-01-01

As probably the only book of its type, this work is aimed at the observer who wants to spend time with something less conventional than the usual fare. Because we usually see objects in space by means of illumination of one kind or another, it has become routine to see them only in these terms. However, part of almost everything that we see is the defining dimension of dark shading, or even the complete obscuration of entire regions in space. Thus this book is focused on everything dark in space: those dark voids in the stellar fabric that mystified astronomers of old; the dark lanes reported in many star clusters; the magical dust belts or dusty regions that have given so many galaxies their identities; the great swirling 'folds' that we associate with bright nebulae; the small dark feature detectable even in some planetary nebulae; and more. Many observers pay scant attention to dark objects and details. Perhaps they are insufficiently aware of them or of the viewing potential they hold, but also it may be...

Near-field optical microscopy with a scanning tunneling microscope

International Nuclear Information System (INIS)

Barbara, A.; Lopez-Rios, T.; Quemerais, P.

2005-01-01

A homemade apertureless near-field optical microscope using a scanning tunneling microscope (STM) is described. The experimental set-up simultaneously provides optical and topographic images of the sample. Technical details and features of the set-up are presented, together with results demonstrating the sub-wavelength resolution achieved as well as its sensitivity to dielectric contrasts. We show that the use of a STM permits to precisely control very small distances between the tip and the sample which is a great advantage to excite localized optical resonances between the tip and the surface

Atomistic modeling trap-assisted tunneling in hole tunnel field effect transistors

Science.gov (United States)

Long, Pengyu; Huang, Jun Z.; Povolotskyi, Michael; Sarangapani, Prasad; Valencia-Zapata, Gustavo A.; Kubis, Tillmann; Rodwell, Mark J. W.; Klimeck, Gerhard

2018-05-01

Tunnel Field Effect Transistors (FETs) have the potential to achieve steep Subthreshold Swing (S.S.) below 60 mV/dec, but their S.S. could be limited by trap-assisted tunneling (TAT) due to interface traps. In this paper, the effect of trap energy and location on OFF-current (IOFF) of tunnel FETs is evaluated systematically using an atomistic trap level representation in a full quantum transport simulation. Trap energy levels close to band edges cause the highest leakage. Wave function penetration into the surrounding oxide increases the TAT current. To estimate the effects of multiple traps, we assume that the traps themselves do not interact with each other and as a whole do not modify the electrostatic potential dramatically. Within that model limitation, this numerical metrology study points to the critical importance of TAT in the IOFF in tunnel FETs. The model shows that for Dit higher than 1012/(cm2 eV) IO F F is critically increased with a degraded IO N/IO F F ratio of the tunnel FET. In order to have an IO N/IO F F ratio higher than 104, the acceptable Dit near Ev should be controlled to no larger than 1012/(cm2 eV) .

Study on Oxygen Supply Standard for Physical Health of Construction Personnel of High-Altitude Tunnels

Directory of Open Access Journals (Sweden)

Chun Guo

2015-12-01

Full Text Available The low atmospheric pressure and low oxygen content in high-altitude environment have great impacts on the functions of human body. Especially for the personnel engaged in complicated physical labor such as tunnel construction, high altitude can cause a series of adverse physiological reactions, which may result in multiple high-altitude diseases and even death in severe cases. Artificial oxygen supply is required to ensure health and safety of construction personnel in hypoxic environments. However, there are no provisions for oxygen supply standard for tunnel construction personnel in high-altitude areas in current tunnel construction specifications. As a result, this paper has theoretically studied the impacts of high-altitude environment on human bodies, analyzed the relationship between labor intensity and oxygen consumption in high-altitude areas and determined the critical oxygen-supply altitude values for tunnel construction based on two different standard evaluation systems, i.e., variation of air density and equivalent PIO2. In addition, it has finally determined the oxygen supply standard for construction personnel in high-altitude areas based on the relationship between construction labor intensity and oxygen consumption.

International survey of seat belt use exemptions.

Science.gov (United States)

Weiss, H; Sirin, H; Levine, J A; Sauber, E

2006-08-01

Substantial evidence of seatbelt efficacy has been shown by several studies, and it is widely recommended that motor vehicle occupants use properly fitted seat belts. However, some (but a heretofore unknown number of) countries with national seat belt laws permit various exemptions which may lower use rates. The aim of this study was to survey the variety of exemptions to national seat belt laws. This investigation relied on identifying respondents from national traffic safety agencies, other governmental and non-governmental organizations, Internet searches, personal contacts, and other sources. Questionnaires were deployed through a web based survey supplemented by email and postal versions. Responses were received from 30 countries of which 28 (93.7%) had a national seat belt law. About two thirds (63.7%) of the 28 national laws applied to both front and back seat passengers. The leading exemption types included vehicles made before a certain year (n = 13), antique vehicles (n = 12), military vehicles (n = 11), buses (n = 9), and emergency vehicles (n = 8). Most responding countries reported one or more specific categories of individuals as exempt including those with medical exemptions (n = 20), taxi drivers (n = 11), police (n = 9), emergency medical personnel (n = 8), physically disabled people (n = 6), and pregnant women (n = 6). Out of 26 responses to the question regarding current level of enforcement, 42.3% felt enforcement was "very good or good" and 57.7% characterized it as "fair or poor". This study represents one of the largest international traffic law surveys reported. Most national seatbelt laws offer perilous exemptions to a broad array of vehicle types and road user groups. These findings, coupled with concern over the level of enforcement in the majority of countries surveyed, suggest that international road safety efforts have a long way to go to improve coverage and enforcement of national seat belt laws.

Lowest order in inelastic tunneling approximation : efficient scheme for simulation of inelastic electron tunneling data

NARCIS (Netherlands)

Rossen, E.T.R.; Flipse, C.F.J.; Cerda, J.I.

2013-01-01

We have developed an efficient and accurate formalism which allows the simulation at the ab initio level of inelastic electron tunneling spectroscopy data under a scanning tunneling microscope setup. It exploits fully the tunneling regime by carrying out the structural optimization and vibrational

Scanning tunneling microscopic images and scanning tunneling spectra for coupled rectangular quantum corrals

International Nuclear Information System (INIS)

Mitsuoka, Shigenori; Tamura, Akira

2011-01-01

Assuming that an electron confined by double δ-function barriers lies in a quasi-stationary state, we derived eigenstates and eigenenergies of the electron. Such an electron has a complex eigenenergy, and the imaginary part naturally leads to the lifetime of the electron associated with tunneling through barriers. We applied this point of view to the electron confined in a rectangular quantum corral (QC) on a noble metal surface, and obtained scanning tunneling microscopic images and a scanning tunneling spectrum consistent with experimental ones. We investigated the electron states confined in coupled QCs and obtained the coupled states constructed with bonding and anti-bonding states. Using those energy levels and wavefunctions we specified scanning tunneling microscope (STM) images and scanning tunneling spectra (STS) for the doubly and triply coupled QCs. In addition we pointed out the feature of resonant electron states associated with the same QCs at both ends of the triply coupled QCs.

Effect of reinforcement element folds on stresses in NPP containment shell in the zone of technological tunnels

International Nuclear Information System (INIS)

Ul'yanov, A.N.; Medvedev, V.N.; Kiselev, A.S.

1993-01-01

Basing on the results of experimental and calculational studies of stressed state in the zone of a technological tunnel with one-side thicker part the approximated problem solution taking into account the effect of reinforcement element folds on opening zone stressed state is obtained. The great effect of reinforcement ropes on shell stressed state in the zone of technological tunnels, which causes the necessity of its accounting during this zone design, is revealed. Special attention shoul be paid to the sections, where the stretching stresses arising as a result of bundle bending are not compensated (sections of bundle fold origin from normal trajectory)

The "One Belt and One Road" :the Bridge between the Chinese Dream and the World Dream

Institute of Scientific and Technical Information of China (English)

Zhao; Zhouxian; Liu; Guang

2015-01-01

To build the "One Belt and One Road" is the profound strategic conception put forward by the CPC Central Committee with Comrade Xi Jinping as the General Secretary,focusing on adherence to and further development of socialism with Chinese characteristics and realizing the Chinese dream of great rejuvenation of the Chinese nation.To seize the opportunity to promote implementation of the strategic conception is bound to open up a new situation and create new opportunities to realize the Chinese dream,and will inject more new energy and new vitality into the world dream.

Backfilling of deposition tunnels: Use of bentonite pellets

International Nuclear Information System (INIS)

Dixon, David; Sanden, Torbjoern; Jonsson, Esther; Hansen, Johanna

2011-02-01

The state of knowledge related to use of bentonite pellets as part of backfill or other gap filling components in repository applications is reviewed. How the pellets interact with adjacent sealing materials and the surrounding rock mass is a critical aspect in determining backfill behaviour. The key features and processes that determine how the pellet component of the KBS-3V deposition tunnel backfill will behave are discussed and recommendations related to what additional information needs to be developed are provided. Experiences related to pellet material composition, size, shape, placement options and more importantly, the density to which they can be placed all indicate that there are significant limitations to the achievable as-placed density of bentonite pellet fill. Low as-placed density of the pellet fill component of the backfill is potentially problematic as the outermost regions of tunnel backfill will be the first region of the backfill to be contacted by water entering the tunnels. It is also through this region that initial water movement along the length of the deposition tunnels will occur. This will greatly influence the operations in a tunnel, especially with respect to situations where water is exiting the downstream face of still open deposition tunnels. Pellet-filled regions are also sensitive to groundwater salinity, susceptible to development of piping features and subsequent mechanical erosion by through flowing water, particularly in the period preceding deposition tunnel closure. A review of the experiences of various organisations considering use of bentonite-pellet materials as part of buffer or backfill barriers is provided in this document. From this information, potential options and limitations to use of pellets or pellet-granule mixtures in backfill are identified. Of particular importance is identification of the apparent upper-limits of dry density to which such materials can to be placed in the field. These bounds will

Backfilling of deposition tunnels: Use of bentonite pellets

Energy Technology Data Exchange (ETDEWEB)

Dixon, David (Atomic Energy of Canada Limited (Canada)); Sanden, Torbjoern (Clay Technology AB (Sweden)); Jonsson, Esther (Swedish Nuclear Fuel and Waste Mangaement Co. (Sweden)); Hansen, Johanna (Posiva Oy (Finland))

2011-02-15

The state of knowledge related to use of bentonite pellets as part of backfill or other gap filling components in repository applications is reviewed. How the pellets interact with adjacent sealing materials and the surrounding rock mass is a critical aspect in determining backfill behaviour. The key features and processes that determine how the pellet component of the KBS-3V deposition tunnel backfill will behave are discussed and recommendations related to what additional information needs to be developed are provided. Experiences related to pellet material composition, size, shape, placement options and more importantly, the density to which they can be placed all indicate that there are significant limitations to the achievable as-placed density of bentonite pellet fill. Low as-placed density of the pellet fill component of the backfill is potentially problematic as the outermost regions of tunnel backfill will be the first region of the backfill to be contacted by water entering the tunnels. It is also through this region that initial water movement along the length of the deposition tunnels will occur. This will greatly influence the operations in a tunnel, especially with respect to situations where water is exiting the downstream face of still open deposition tunnels. Pellet-filled regions are also sensitive to groundwater salinity, susceptible to development of piping features and subsequent mechanical erosion by through flowing water, particularly in the period preceding deposition tunnel closure. A review of the experiences of various organisations considering use of bentonite-pellet materials as part of buffer or backfill barriers is provided in this document. From this information, potential options and limitations to use of pellets or pellet-granule mixtures in backfill are identified. Of particular importance is identification of the apparent upper-limits of dry density to which such materials can to be placed in the field. These bounds will

Ivar Giaever, Tunneling, and Superconductors

Science.gov (United States)

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

Physics of optimal resonant tunneling

NARCIS (Netherlands)

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

1997-01-01

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

Tectonic setting of the Great Dyke, Chembadzi, Chewore and Atchiza layered complexes in Zimbabwe and Mozambique

International Nuclear Information System (INIS)

Master, S.

1990-01-01

The Great Dyke of Zimbabwe is one of the largest ultramafic-mafic layered igneous complexexs in the world. Because of the economic importance of large layered intrusions like the Great Dyke, their tectonic setting is of great interest. The Chembadzi complex is a 14 km long, dyke-like layered intrusion up to 800m wide. The Chewore complex, which was thought to have the structure of an irregular lopolith, outcrops over an area of about 200 km in horst blocks in the lower Zambezi Valley in northern Zimbabwe. The Atchiza complex is situated just north of the Cahora Bassa lake and the Zambezi River valley in Mozambique. In considering the tectonic setting of the Great Dyke and its correlatives, most attention has been focussed on events in the Limpopo Mobile Belt, which were responsible for producing the fractures in the Zimbabwe craton that is occupied by the intrusives. 39 refs

Spin-polarized tunneling with GaAs tips in scanning tunneling microscopy

NARCIS (Netherlands)

Prins, M.W.J.; Jansen, R.; Kempen, van H.

1996-01-01

We describe a model as well as experiments on spin-polarized tunneling with the aid of optical spin orientation. This involves tunnel junctions between a magnetic material and gallium arsenide (GaAs), where the latter is optically excited with circularly polarized light in order to generate

Submucosal tunneling techniques: current perspectives.

Science.gov (United States)

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

2014-01-01

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

Ultrafast scanning tunneling microscopy

Energy Technology Data Exchange (ETDEWEB)

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

1995-09-01

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

The comparison between limited open carpal tunnel release using direct vision and tunneling technique and standard open carpal tunnel release: a randomized controlled trial study.

Science.gov (United States)

Suppaphol, Sorasak; Worathanarat, Patarawan; Kawinwongkovit, Viroj; Pittayawutwinit, Preecha

2012-04-01

To compare the operative outcome of carpal tunnel release between limited open carpal tunnel release using direct vision and tunneling technique (group A) with standard open carpal tunnel release (group B). Twenty-eight patients were enrolled in the present study. A single blind randomized control trial study was conducted to compare the postoperative results between group A and B. The study parameters were Levine's symptom severity and functional score, grip and pinch strength, and average two-point discrimination. The postoperative results between two groups were comparable with no statistical significance. Only grip strength at three months follow up was significantly greater in group A than in group B. The limited open carpal tunnel release in the present study is effective comparable to the standard open carpal tunnel release. The others advantage of this technique are better cosmesis and improvement in grip strength at the three months postoperative period.

13th Australian tunnelling conference. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-07-01

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

Does flexible tunnel drilling affect the femoral tunnel angle measurement after anterior cruciate ligament reconstruction?

Science.gov (United States)

Muller, Bart; Hofbauer, Marcus; Atte, Akere; van Dijk, C Niek; Fu, Freddie H

2015-12-01

To quantify the mean difference in femoral tunnel angle (FTA) as measured on knee radiographs between rigid and flexible tunnel drilling after anatomic anterior cruciate ligament (ACL) reconstruction. Fifty consecutive patients that underwent primary anatomic ACL reconstruction with a single femoral tunnel drilled with a flexible reamer were included in this study. The control group was comprised of 50 patients all of who underwent primary anatomic ACL reconstruction with a single femoral tunnel drilled with a rigid reamer. All femoral tunnels were drilled through a medial portal to ensure anatomic tunnel placement. The FTA was determined from post-operative anterior-to-posterior (AP) radiographs by two independent observers. A 5° difference between the two mean FTA was considered clinically significant. The average FTA, when drilled with a rigid reamer, was 42.0° ± 7.2°. Drilling with a flexible reamer resulted in a mean FTA of 44.7° ± 7.0°. The mean difference of 2.7° was not statistically significant. The intraclass correlation coefficient for inter-tester reliability was 0.895. The FTA can be reliably determined from post-operative AP radiographs and provides a useful and reproducible metric for characterizing femoral tunnel position after both rigid and flexible femoral tunnel drilling. This has implications for post-operative evaluation and preoperative treatment planning for ACL revision surgery. IV.

Correlating nerve conduction studies and clinical outcome measures on carpal tunnel syndrome: lessons from a randomized controlled trial

NARCIS (Netherlands)

Schrijver, H.M.; Gerritsen, A.A.M.; Strijers, R.L.; Uitdehaag, B.M.J.; Scholten, R.J.P.M.; de Vet, H.C.W.; Bouter, L.M.

2005-01-01

The reported relationships between nerve conduction studies (NCS) and outcome measures in carpal tunnel syndrome (CTS) are weak to moderate. However, selection of patients may have confounded nonrandomized studies. NCS have potentially great value in selecting patients for a specific treatment and

«Great Eurasia»: interests and possibilities of Russia at interaction with China

Directory of Open Access Journals (Sweden)

Elena M. Kuzmina

2017-01-01

Full Text Available The Author analyzes the regulatory structure proposed by the President Putin’s strategy of «Great Eurasia» in Russian official and economic policy frameworks and development programmes, Examines internal and external factors affecting the Eurasian Union, as a base for building relationships within the «Great Eurasia». The emphasis the author makes the EAEU’s interest in the development of economic relations with the countries of «Great Eurasia» with the use of the Union. He also analyzes the dynamics of the negotiation process for conclusion of trade and economic agreements between the EEC and China and the challenges and opportunities of member countries in economic relations with China. Considered the level of compatibility of the Eurasian Union and the initiative «One belt and one road». A separate part of the article devoted to economic cooperation of Russia and China and their possible interaction in the construction of the Grand Eurasia.  

Derivation of the tunnelling exchange time for the model of trap-assisted tunnelling

International Nuclear Information System (INIS)

Racko, J.; Ballo, P.; Benko, P.; Harmatha, L.; Grmanova, A.; Breza, J.

2014-01-01

We present derivation of the tunnelling exchange times that play the key role in the model of trap assisted tunnelling (TAT) considering the electron and hole exchange processes between the trapping centre lying in the forbidden band of the semiconductor and the conduction band, valence band or a metal. All exchange processes are quantitatively described by respective exchange times. The reciprocal values of these exchange times represent the frequency with which the exchange processes contribute to the probability of occupation of the trap by free charge carriers. The crucial problem in any model of TAT is the calculation of the occupation probability. In our approach this probability is expressed in terms of only thermal and tunnelling exchange times. The concept of tunnelling exchange times presents a dominant contribution to our model of TAT. The new approach allows to simply calculate the probability of occupation of the trapping centre by a free charge carrier and subsequently to get the thermal and tunnelling generation-recombination rates occurring in the continuity equations. This is why the TAT model based on thermal and tunnelling exchange times is suitable for simulating the electrical properties of semiconductor nanostructures in which quantum mechanical phenomena play a key role. (authors)

Electronic noise of superconducting tunnel junction detectors

International Nuclear Information System (INIS)

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

1994-01-01

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

Tunneling of Atoms, Nuclei and Molecules

International Nuclear Information System (INIS)

Bertulani, C.A.

2015-01-01

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

Paired Magmatic-Metallogenic Belts in Myanmar - an Andean Analogue?

Science.gov (United States)

Gardiner, Nicholas; Robb, Laurence; Searle, Michael; Morley, Christopher

2015-04-01

Myanmar (Burma) is richly endowed in precious and base metals, having one of the most diverse collections of natural resources in SE Asia. Its geological history is dominated by the staged closing of Tethys and the suturing of Gondwana-derived continental fragments onto the South China craton during the Mesozoic-Cenozoic. The country is located at a crucial geologic juncture where the main convergent Tethyan collision zone swings south around the Namche Barwa Eastern Himalayan syntaxis. However, despite recent work, the geological and geodynamic history of Myanmar remains enigmatic. Plate margin processes, magmatism, metasomatism and the genesis of mineral deposits are intricately linked, and there has long been recognized a relationship between the distribution of certain mineral deposit types, and the tectonic settings which favour their genesis. A better knowledge of the regional tectonic evolution of a potential exploration jurisdiction is therefore crucial to understanding its minerals prospectivity. This strong association between tectonics and mineralization can equally be applied in reverse. By mapping out the spatial, and temporal, distribution of presumed co-genetic mineral deposits, coupled with an understanding of their collective metallogenetic origin, a better appreciation of the tectonic evolution of a terrane may be elucidated. Identification and categorization of metallotects within a geodynamically-evolving terrane thus provides a complimentary tool to other methodologies (e.g. geochemical, geochronological, structural, geophysical, stratigraphical), for determining the tectonic history and inferred geodynamic setting of that terrane through time. Myanmar is one such study area where this approach can be undertaken. Here are found two near-parallel magmatic belts, which together contain a significant proportion of that country's mineral wealth of tin, tungsten, copper, gold and silver. Although only a few 100 km's apart, these belts exhibit a

Subway platform air quality: Assessing the influences of tunnel ventilation, train piston effect and station design

Science.gov (United States)

Moreno, T.; Pérez, N.; Reche, C.; Martins, V.; de Miguel, E.; Capdevila, M.; Centelles, S.; Minguillón, M. C.; Amato, F.; Alastuey, A.; Querol, X.; Gibbons, W.

2014-08-01

A high resolution air quality monitoring campaign (PM, CO2 and CO) was conducted on differently designed station platforms in the Barcelona subway system under: (a) normal forced tunnel ventilation, and (b) with daytime tunnel ventilation systems shut down. PM concentrations are highly variable (6-128 μgPM1 m-3, 16-314 μgPM3 m-3, and 33-332 μgPM10 m-3, 15-min averages) depending on ventilation conditions and station design. Narrow platforms served by single-track tunnels are heavily dependent on forced tunnel ventilation and cannot rely on the train piston effect alone to reduce platform PM concentrations. In contrast PM levels in stations with spacious double-track tunnels are not greatly affected when tunnel ventilation is switched off, offering the possibility of significant energy savings without damaging air quality. Sampling at different positions along the platform reveals considerable lateral variation, with the greatest accumulation of particulates occurring at one end of the platform. Passenger accesses can dilute PM concentrations by introducing cleaner outside air, although lateral down-platform accesses are less effective than those positioned at the train entry point. CO concentrations on the platform are very low (≤1 ppm) and probably controlled by ingress of traffic-contaminated street-level air. CO2 averages range from 371 to 569 ppm, changing during the build-up and exchange of passengers with each passing train.

Type QH-200 conveyor-belt nuclear scale

International Nuclear Information System (INIS)

Li Shuming; Dong Shiyuan; Li Furong; Wan Zemin

1991-01-01

Type QH-200 conveyor-belt nuclear scale is a reliable and on-line device that weighs solids mass flow continuously by γ-ray absorption and scattering. The operation principle and measuring method are described. And some factors influencing the accuracy are discussed. The full scale total weight of type QH-200 nuclear scale is 10 6 t. The result of calibration in the industrial field shows that the accuracy of QH-200 is better than ±1.0% for typical belt loading

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

Energy Technology Data Exchange (ETDEWEB)

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

1994-04-01

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

Charge Islands Through Tunneling

Science.gov (United States)

Robinson, Daryl C.

2002-01-01

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

Tunneling progress on the Yucca Mountain Project

International Nuclear Information System (INIS)

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

1996-01-01

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

The Sino-American belt study: nickel and cobalt exposure, epidemiology, and clinical considerations.

Science.gov (United States)

Hamann, Dathan; Hamann, Carsten; Li, Lin-Feng; Xiang, Hailian; Hamann, Kylin; Maibach, Howard; Taylor, James S; Thyssen, Jacob P

2012-01-01

Nickel and cobalt are common causes of metal allergy. The objective of this study was to investigate nickel and cobalt exposure in belt buckles by testing 701 belts purchased in China and the United States and to consider the prevalence of nickel allergy and its relevance among Chinese patients. Seven hundred one belt buckles purchased in China and the United States were tested for nickel and cobalt release. Six hundred thirty-one Chinese patients with suspected allergic contact dermatitis were patch tested and interviewed to determine clinical relevance of results. The Chinese and American literature was reviewed to investigate trends in nickel prevalence over the past decades. Sixty percent (n = 219) of belts purchased in China (n = 365) released nickel, and 0.5% (n = 2) released cobalt; 55.7% (n = 187) in the United States (n = 336) released nickel, and 0.9% (n = 3) released cobalt. Belt dermatitis was a significant clinical finding in 34.8% of Chinese nickel-allergic patients. Literature review suggests increasing nickel allergy prevalence in the United States and China. Metallic belt buckles are an important source of nickel exposure to consumers. Belts from lowest socioeconomic vendors were more likely to release nickel. Belts with silver color and dark metallic color were more likely to release nickel and cobalt, respectively. Clinical findings show belt dermatitis in China to be a problem.

The physical imitation experiments of nuclear belt weight scaler

International Nuclear Information System (INIS)

Shi Qicun; Wang Mingqian; Sun Jinhua; Li Zhonghao

1993-01-01

The physical imitation experiments of the nuclear belt weight scaler (NBWS) were performed with a coal-loaded belt. The linearity, repetition and long-time stability; of the NBWS were measured. And the influence of pile shape, load bias and the composition of coal on weight calculation were studied

Peak stresses shift from femoral tunnel aperture to tibial tunnel aperture in lateral tibial tunnel ACL reconstructions: a 3D graft-bending angle measurement and finite-element analysis.

Science.gov (United States)

Van Der Bracht, Hans; Tampere, Thomas; Beekman, Pieter; Schepens, Alexander; Devriendt, Wouter; Verdonk, Peter; Victor, Jan

2018-02-01

To investigate the effect of tibial tunnel orientation on graft-bending angle and stress distribution in the ACL graft. Eight cadaveric knees were scanned in extension, 45°, 90°, and full flexion. 3D reconstructions with anatomically placed anterior cruciate ligament (ACL) grafts were constructed with Mimics 14.12 ® . 3D graft-bending angles were measured for classic medial tibial tunnels (MTT) and lateral tibial tunnels (LTT) with different drill-guide angles (DGA) (45°, 55°, 65°, and 75°). A pivot shift was performed on 1 knee in a finite-element analysis. The peak stresses in the graft were calculated for eight different tibial tunnel orientations. In a classic anatomical ACL repair, the largest graft-bending angle and peak stresses are seen at the femoral tunnel aperture. The use of a different DGA at the tibial side does not change the graft-bending angle at the femoral side or magnitude of peak stresses significantly. When using LTT, the largest graft-bending angles and peak stresses are seen at the tibial tunnel aperture. In a classic anatomical ACL repair, peak stresses in the ACL graft are found at the femoral tunnel aperture. When an LTT is used, peak stresses are similar compared to classic ACL repairs, but the location of the peak stress will shift from the femoral tunnel aperture towards the tibial tunnel aperture. the risk of graft rupture is similar for both MTTs and LTTs, but the location of graft rupture changes from the femoral tunnel aperture towards the tibial tunnel aperture, respectively. I.

Structural appraisal of the Gadag schist belt from gravity investigations

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

From qualitative analysis of the gravity data, several tectonic features are ... major types of schist belts are identified in the ... Dharwar craton; Gadag schist belt; gravity method; inversion. ..... the Research Associateship of Dr D Himabindu.

Hypersonic Tunnel Facility (HTF)

Data.gov (United States)

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

Understanding quaternions and the Dirac belt trick

International Nuclear Information System (INIS)

Staley, Mark

2010-01-01

The Dirac belt trick is often employed in physics classrooms to show that a 2π rotation is not topologically equivalent to the absence of rotation whereas a 4π rotation is, mirroring a key property of quaternions and their isomorphic cousins, spinors. The belt trick can leave the student wondering if a real understanding of quaternions and spinors has been achieved, or if the trick is just an amusing analogy. The goal of this paper is to demystify the belt trick and to show that it suggests an underlying four-dimensional parameter space for rotations that is simply connected. An investigation into the geometry of this four-dimensional space leads directly to the system of quaternions, and to an interpretation of three-dimensional vectors as the generators of rotations in this larger four-dimensional world. The paper also shows why quaternions are the natural extension of complex numbers to four dimensions. The level of the paper is suitable for undergraduate students of physics.

Large enhancement of highly energetic electrons in the outer radiation belt and its transport into the inner radiation belt inferred from MDS-1 satellite observations

Science.gov (United States)

Obara, T.; Matsumoto, H.

2016-03-01

We have examined a large increase of relativistic electrons in the outer radiation belt and its penetration into the inner radiation belt over slot region using the MDS-1 satellite observations. Result of analyses demonstrates that a large increase took place in the spring and autumn seasons, and we have newly confirmed that the penetration of outer belt electrons to the inner radiation zone took place during the big magnetic storms by examining a pitch angle distribution of the penetrating electrons.

Aortic ruptures in seat belt wearers.

Science.gov (United States)

Arajärvi, E; Santavirta, S; Tolonen, J

1989-09-01

Several investigations have indicated that rupture of the thoracic aorta is one of the leading causes of immediate death in victims of road traffic accidents. In Finland in 1983, 92% of front-seat passengers were seat belt wearers on highways and 82% in build-up areas. The mechanisms of rupture of the aorta have been intensively investigated, but the relationship between seat belt wearing and injury mechanisms leading to aortic rupture is still largely unknown. This study comprises 4169 fatally injured victims investigated by the Boards of Traffic Accident Investigation of Insurance Companies during the period 1972 to 1985. Chest injuries were recorded as the main cause of death in 1121 (26.9%) victims, 207 (5.0%) of those victims having worn a seat belt. Aortic ruptures were found at autopsy in 98 victims and the exact information of the location of the aortic tears was available in 68. For a control group, we analyzed 72 randomly chosen unbelted victims who had a fatal aortic rupture in similar accidents. The location of the aortic rupture in unbelted victims was more often in the ascending aorta, especially in drivers, whereas in seat belt wearers the distal descending aorta was statistically more often ruptured, especially in right-front passengers (p less than 0.05). The steering wheel predominated statistically as the part of the car estimated to have caused the injury in unbelted victims (37/72), and some interior part of the car was the most common cause of fatal thoracic impacts in seat belt wearers (48/68) (p less than 0.001). The mechanism of rupture of the aorta in the classic site just distal to the subclavian artery seems to be rapid deceleration, although complex body movements are also responsible in side impact collisions. The main mechanism leading to rupture of the ascending aorta seems to be severe blow to the bony thorax. This also often causes associated thoracic injuries, such as heart rupture and sternal fracture. Injuries in the ascending

Klein tunneling phenomenon with pair creation process

Science.gov (United States)

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

2018-01-01

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

Reduction of charge trapping and electron tunneling in SIMOX by supplemental implantation of oxygen

International Nuclear Information System (INIS)

Stahlbush, R.E.; Hughes, H.L.; Krull, W.A.

1993-01-01

Silicon-on-insulator, SOI, technologies are being aggressively pursued to produce high density, high speed, radiation tolerant electronics. The dielectric isolation of the buried oxide makes it possible to design integrated circuits that greatly minimize single event upset and eliminate dose-rate induced latchup and upset. The reduction of excess-silicon related defects in SIMOX by the supplemental implantation of oxygen has been examined. The supplemental implant is 6% of the oxygen dose used to form the buried oxide, and is followed by a 1,000 C anneal, in contrast to the >1,300 C anneal used to form the buried oxide layer of SIMOX. The defects examined include shallow electron traps, deep hole traps, and silicon clusters. The radiation-induced shallow electron and deep hole trapping are measured by cryogenic detrapping and isothermal annealing techniques. The low-field (3 to 6 MV/cm) electron tunneling is interpreted as due to a two phase mixture of stoichiometric SiO 2 and Si clusters a few nm in size. Single and triple SIMOS samples have been examined. All of the defects are reduced by the supplemental oxygen processing. Shallow electron trapping is reduced by an order of magnitude. Because of the larger capture cross section for hole trapping, hole trapping is not reduced as much. The low-field electron tunneling due to Si clusters is also significantly reduced. Both uniform and nonuniform electron tunneling have been observed in SIMOX samples without supplement processing. In samples exhibiting only uniform tunneling, electron capture at holes has been observed. The nonuniform tunneling is superimposed upon the uniform tunneling and is characterized by current spiking

Tunneling time, what is its meaning?

International Nuclear Information System (INIS)

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

2015-01-01

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

The Belt voice: Acoustical measurements and esthetic correlates

Science.gov (United States)

Bounous, Barry Urban

This dissertation explores the esthetic attributes of the Belt voice through spectral acoustical analysis. The process of understanding the nature and safe practice of Belt is just beginning, whereas the understanding of classical singing is well established. The unique nature of the Belt sound provides difficulties for voice teachers attempting to evaluate the quality and appropriateness of a particular sound or performance. This study attempts to provide answers to the question "does Belt conform to a set of measurable esthetic standards?" In answering this question, this paper expands on a previous study of the esthetic attributes of the classical baritone voice (see "Vocal Beauty", NATS Journal 51,1) which also drew some tentative conclusions about the Belt voice but which had an inadequate sample pool of subjects from which to draw. Further, this study demonstrates that it is possible to scientifically investigate the realm of musical esthetics in the singing voice. It is possible to go beyond the "a trained voice compared to an untrained voice" paradigm when evaluating quantitative vocal parameters and actually investigate what truly beautiful voices do. There are functions of sound energy (measured in dB) transference which may affect the nervous system in predictable ways and which can be measured and associated with esthetics. This study does not show consistency in measurements for absolute beauty (taste) even among belt teachers and researchers but does show some markers with varying degrees of importance which may point to a difference between our cognitive learned response to singing and our emotional, more visceral response to sounds. The markers which are significant in determining vocal beauty are: (1) Vibrancy-Characteristics of vibrato including speed, width, and consistency (low variability). (2) Spectral makeup-Ratio of partial strength above the fundamental to the fundamental. (3) Activity of the voice-The quantity of energy being produced. (4

Transonic Dynamics Tunnel (TDT)

Data.gov (United States)

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

Effects of neglecting carrier tunneling on electrostatic potential in calculating direct tunneling gate current in deep submicron MOSFETs

OpenAIRE

Hakim, MMA; Haque, A

2002-01-01

We investigate the validity of the assumption of neglecting carrier tunneling effects on self-consistent electrostatic potential in calculating direct tunneling gate current in deep submicron MOSFETs. Comparison between simulated and experimental results shows that for accurate modeling of direct tunneling current, tunneling effects on potential profile need to be considered. The relative error in gate current due to neglecting carrier tunneling is higher at higher gate voltages and increases...

Road and Railroad Tunnels

Data.gov (United States)

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

PUREX Storage Tunnels dangerous waste permit application

International Nuclear Information System (INIS)

1991-12-01

The PUREX Storage Tunnels are a mixed waste storage unit consisting of two underground railroad tunnels: Tunnel Number 1 designated 218-E-14 and Tunnel Number 2 designated 218-E-15. The two tunnels are connected by rail to the PUREX Plant and combine to provide storage space for 48 railroad cars (railcars). The PUREX Storage Tunnels provide a long-term storage location for equipment removed from the PUREX Plant. Transfers into the PUREX Storage Tunnels are made on an as-needed basis. Radioactively contaminated equipment is loaded on railcars and remotely transferred by rail into the PUREX Storage Tunnels. Railcars act as both a transport means and a storage platform for equipment placed into the tunnels. This report consists of part A and part B. Part A reports on amounts and locations of the mixed water. Part B permit application consists of the following: Facility Description and General Provisions; Waste Characteristics; Process Information; Groundwater Monitoring; Procedures to Prevent Hazards; Contingency Plan; Personnel Training; Exposure Information Report

Monitoring, Analyzing and Assessing Radiation Belt Loss and Energization

Science.gov (United States)

Daglis, I.; Balasis, G.; Bourdarie, S.; Horne, R.; Khotyaintsev, Y.; Mann, I.; Santolik, O.; Turner, D.; Anastasiadis, A.; Georgiou, M.; Giannakis, O.; Papadimitriou, C.; Ropokis, G.; Sandberg, I.; Angelopoulos, V.; Glauert, S.; Grison, B., Kersten T.; Kolmasova, I.; Lazaro, D.; Mella, M.; Ozeke, L.; Usanova, M.

2013-09-01

We present the concept, objectives and expected impact of the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Loss and Energization) project, which is being implemented by a consortium of seven institutions (five European, one Canadian and one US) with support from the European Community's Seventh Framework Programme. The MAARBLE project employs multi-spacecraft monitoring of the geospace environment, complemented by ground-based monitoring, in order to analyze and assess the physical mechanisms leading to radiation belt particle energization and loss. Particular attention is paid to the role of ULF/VLF waves. A database containing properties of the waves is being created and will be made available to the scientific community. Based on the wave database, a statistical model of the wave activity dependent on the level of geomagnetic activity, solar wind forcing, and magnetospheric region will be developed. Multi-spacecraft particle measurements will be incorporated into data assimilation tools, leading to new understanding of the causal relationships between ULF/VLF waves and radiation belt dynamics. Data assimilation techniques have been proven as a valuable tool in the field of radiation belts, able to guide 'the best' estimate of the state of a complex system. The MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project has received funding from the European Union’s Seventh Framework Programme (FP7-SPACE-2011-1) under grant agreement no. 284520.

On the existence of a comet belt beyond Neptune

International Nuclear Information System (INIS)

Fernandez, J.A.

1980-01-01

The possible existence of a comet belt in connection with the origin of the short-period comets is analysed. It is noted that the current theory - that these comets originate as near-parabolic comets captured by Jupiter and the other giant planets - implies an excessive wastage of comets lost in hyperbolic orbits, which is avoided in the present model. The following picture is predicted. Solid conglomerates up to approximately 10 18 g were formed by gravitational instabilities in the belt region (about 35 to 50 AU). A further fragmentation-accretion process led to a power-law mass distribution similar to that observed in the asteroids. Since then, close encounters between members of the belt have provoked the diffusion of some of them with the effect that they have become subject to the strong perturbations of Neptune. Of these a small number pass from one planet to the next inside and end as short-period comets. By means of a Monte Carlo method, the influence of close encounters between belt comets is then studied in relation to the diffusion of their orbits. It is concluded that if such a belt contains members with masses equal to or greater than that of Ceres, the orbital diffusion could proceed fast enough to maintain the number of observed short-period comets in a steady state. (author)

Effects of a Belt on Intra-Abdominal Pressure during Weight Lifting.

Science.gov (United States)

1988-03-01

potentially injurious b compressive forces on spinal discs during lifting. To investigate the effects of a standard lifting belt on lAP and lifting mechanics... injurious compressive forces on spinal discs during lifting. To investigate the effects of a standard lifting belt on IAP and lifting ! mechanics... weightlifting (7,9). Both olympic and power lifters have used lifting belts for many years, yet virtually no research has been reported which examines

Electrically tunable tunneling rectification magnetoresistance in magnetic tunneling junctions with asymmetric barriers.

Science.gov (United States)

Wang, Jing; Huang, Qikun; Shi, Peng; Zhang, Kun; Tian, Yufeng; Yan, Shishen; Chen, Yanxue; Liu, Guolei; Kang, Shishou; Mei, Liangmo

2017-10-26

The development of multifunctional spintronic devices requires simultaneous control of multiple degrees of freedom of electrons, such as charge, spin and orbit, and especially a new physical functionality can be realized by combining two or more different physical mechanisms in one specific device. Here, we report the realization of novel tunneling rectification magnetoresistance (TRMR), where the charge-related rectification and spin-dependent tunneling magnetoresistance are integrated in Co/CoO-ZnO/Co magnetic tunneling junctions with asymmetric tunneling barriers. Moreover, by simultaneously applying direct current and alternating current to the devices, the TRMR has been remarkably tuned in the range from -300% to 2200% at low temperature. This proof-of-concept investigation provides an unexplored avenue towards electrical and magnetic control of charge and spin, which may apply to other heterojunctions to give rise to more fascinating emergent functionalities for future spintronics applications.

Scanning tunneling microscopy

International Nuclear Information System (INIS)

Binnig, G.; Rohrer, H.

1983-01-01

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

Scanning tunneling microscope nanoetching method

Science.gov (United States)

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

1990-01-01

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

Chinese Policy in Post-Soviet States. «One Belt — One Road Initiative»

Directory of Open Access Journals (Sweden)

Yuliya M. Borisova

2017-01-01

Full Text Available Former Soviet Union countries is of special interest for China. Russian influence in former republics has been declining since the Soviet Union collapsed. China used these changes to start developing of bilateral relations with Central Asia states, as a first priority, and continued with Ukraine, Belorussia, South Caucasus governments. Former Soviet countries’ course to weaken Russian influence helped Chinese policy to be promoted. It has altered from bitty steps to concerted course in the region. China began to play a major role in the trade and economic development of Central Asia, supporting its policy with political mechanisms. To strengthen its positions, Beijing proposed its “One belt - one road” strategic initiative, which consists of two major projects : Silk Road Economic Belt and the 21st Century Maritime Silk Route Economic Belt. These projects involve almost all of the former soviet states, of which Central Asian countries play a major part. This world region is seen in China as a platform for invading European markets, and it also provides a way to avoid trespassing of the Russian borders. In the context of Chinese “One road — one belt” initiative, there is a great concern of the cooperation with EAEU project. EAEU is aimed to provide coordinated unified economic policy with state-members, to guarantee the free movement of goods, capital and labour. Moscow sees its initiative as an instrument for construction of economic and political structure in the region, same as Beijing does. Possibility of two global projects coexistence, which can be distinguished as competitive, is a problem to be solved.   

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

International Nuclear Information System (INIS)

Arnold, G.B.

1987-01-01

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

High-precision pose measurement method in wind tunnels based on laser-aided vision technology

Directory of Open Access Journals (Sweden)

Liu Wei

2015-08-01

Full Text Available The measurement of position and attitude parameters for the isolated target from a high-speed aircraft is a great challenge in the field of wind tunnel simulation technology. In this paper, firstly, an image acquisition method for small high-speed targets with multi-dimensional movement in wind tunnel environment is proposed based on laser-aided vision technology. Combining with the trajectory simulation of the isolated model, the reasonably distributed laser stripes and self-luminous markers are utilized to capture clear images of the object. Then, after image processing, feature extraction, stereo correspondence and reconstruction, three-dimensional information of laser stripes and self-luminous markers are calculated. Besides, a pose solution method based on projected laser stripes and self-luminous markers is proposed. Finally, simulation experiments on measuring the position and attitude of high-speed rolling targets are conducted, as well as accuracy verification experiments. Experimental results indicate that the proposed method is feasible and efficient for measuring the pose parameters of rolling targets in wind tunnels.

Dirac particle tunneling from black rings

International Nuclear Information System (INIS)

Jiang Qingquan

2008-01-01

Recent research shows that Hawking radiation can be treated as a quantum tunneling process, and Hawking temperatures of Dirac particles across the horizon of a black hole can be correctly recovered via the fermion tunneling method. In this paper, motivated by the fermion tunneling method, we attempt to apply the analysis to derive Hawking radiation of Dirac particles via tunneling from black ring solutions of 5-dimensional Einstein-Maxwell-dilaton gravity theory. Finally, it is interesting to find that, as in the black hole case, fermion tunneling can also result in correct Hawking temperatures for the rotating neutral, dipole, and charged black rings.

Metallogenic epoch of the Jiapigou gold belt, Jilin Province, China

Indian Academy of Sciences (India)

Metallogenic epoch of the Jiapigou gold belt, Jilin Province, China: ... The Jiapigou gold belt is located on the northern margin of the North China Craton, and is one of the ... 29, Xueyuan Road, Beijing 100083, People's Republic of China.

Engineers win award for Swiss tunnel

CERN Multimedia

2003-01-01

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

Semiclassical description of resonant tunneling

International Nuclear Information System (INIS)

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

1996-01-01

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

Electron Radiation Belts of the Solar System

Science.gov (United States)

Mauk, Barry; Fox, Nicola

To address the question of what factors dictate similarities and differences between radiation belts, we present comparisons between the electron radiation belt spectra of all five strongly magnetized planets within the solar system: Earth, Jupiter, Saturn, Uranus, and Neptune. We choose the highest intensity observed electron spectrum within each system (highest specifically near 1 MeV) and compare them against expectations based on the so-called Kennel-Petschek limit (KP; 1966) for each system. For evaluating the KP limit, we begin with the new relativis-tically correct formulation of Summers et al. (2009) but then add several refinements of our own. Specifically, we: 1) utilized a much more flexible analytic spectral shape that allows us to accurately fit observed radiation belt spectra; 2) adopt the point of view that the anisotropy parameter is not a free parameter but must take on a minimal value, as originally proposed by Kennel and Petschek (1966); and 3) examine the differential characteristics of the KP limit along the lines of what Schulz and Davidson (1988) performed for the non-relativistic formula-tion. We find that three factors limit the highest electron radiation belt intensities within solar system planetary magnetospheres: a) whistler mode interactions that limit spectral intensities to a differential Kennel-Petschek limit (3 planets); b) the absence of robust acceleration pro-cesses associated with injection dynamics (1 planet); and c) material interactions between the radiation particles and clouds of gas and dust (1 planet).

A Top Pilot Tunnel Preconditioning Method for the Prevention of Extremely Intense Rockbursts in Deep Tunnels Excavated by TBMs

Science.gov (United States)

Zhang, Chuanqing; Feng, Xiating; Zhou, Hui; Qiu, Shili; Wu, Wenping

2012-05-01

The headrace tunnels at the Jinping II Hydropower Station cross the Jinping Mountain with a maximum overburden depth of 2,525 m, where 80% of the strata along the tunnels consist of marble. A number of extremely intense rockbursts occurred during the excavation of the auxiliary tunnels and the drainage tunnel. In particular, a tunnel boring machine (TBM) was destroyed by an extremely intense rockburst in a 7.2-m-diameter drainage tunnel. Two of the four subsequent 12.4-m-diameter headrace tunnels will be excavated with larger size TBMs, where a high risk of extremely intense rockbursts exists. Herein, a top pilot tunnel preconditioning method is proposed to minimize this risk, in which a drilling and blasting method is first recommended for the top pilot tunnel excavation and support, and then the TBM excavation of the main tunnel is conducted. In order to evaluate the mechanical effectiveness of this method, numerical simulation analyses using the failure approaching index, energy release rate, and excess shear stress indices are carried out. Its construction feasibility is discussed as well. Moreover, a microseismic monitoring technique is used in the experimental tunnel section for the real-time monitoring of the microseismic activities of the rock mass in TBM excavation and for assessing the effect of the top pilot tunnel excavation in reducing the risk of rockbursts. This method is applied to two tunnel sections prone to extremely intense rockbursts and leads to a reduction in the risk of rockbursts in TBM excavation.

Conceptual design of a Moving Belt Radiator (MBR) shuttle-attached experiment

Science.gov (United States)

Aguilar, Jerry L.

1990-01-01

The conceptual design of a shuttle-attached Moving Belt Radiator (MBR) experiment is presented. The MBR is an advanced radiator concept in which a rotating belt is used to radiate thermal energy to space. The experiment is developed with the primary focus being the verification of the dynamic characteristics of a rotating belt with a secondary objective of proving the thermal and sealing aspects in a reduced gravity, vacuum environment. The mechanical design, selection of the belt material and working fluid, a preliminary test plan, and program plan are presented. The strategy used for selecting the basic sizes and materials of the components are discussed. Shuttle and crew member requirements are presented with some options for increasing or decreasing the demands on the STS. An STS carrier and the criteria used in the selection process are presented. The proposed carrier for the Moving Belt Radiator experiment is the Hitchhiker-M. Safety issues are also listed with possible results. This experiment is designed so that a belt can be deployed, run at steady state conditions, run with dynamic perturbations imposed, verify the operation of the interface heat exchanger and seals, and finally be retracted into a stowed position for transport back to earth.

Tunneling Ionization of Diatomic Molecules

DEFF Research Database (Denmark)

Svensmark, Jens Søren Sieg

2016-01-01

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

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

KAUST Repository

Useinov, Arthur

2012-06-01

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

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

KAUST Repository

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

2012-01-01

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

Tunneling magnetoresistance and electroresistance in Fe/PbTiO3/Fe multiferroic tunnel junctions

International Nuclear Information System (INIS)

Dai, Jian-Qing

2016-01-01

We perform first-principles electronic structure and spin-dependent transport calculations for a Fe/PbTiO 3 /Fe multiferroic tunnel junction with asymmetric TiO 2 - and PbO-terminated interfaces. We demonstrate that the interfacial electronic reconstruction driven by the in situ screening of ferroelectric polarization, in conjunction with the intricate complex band structure of barrier, play a decisive role in controlling the spin-dependent tunneling. Reversal of ferroelectric polarization results in a transition from insulating to half-metal-like conducting state for the interfacial Pb 6p z orbitals, which acts as an atomic-scale spin-valve by releasing the tunneling current in antiparallel magnetization configuration as the ferroelectric polarization pointing to the PbO-terminated interface. This effect produces large change in tunneling conductance. Our results open an attractive avenue in designing multiferroic tunnel junctions with excellent performance by exploiting the interfacial electronic reconstruction originated from the in situ screening of ferroelectric polarization.

Atomistic nature in band-to-band tunneling in two-dimensional silicon pn tunnel diodes

International Nuclear Information System (INIS)

Tabe, Michiharu; Tan, Hoang Nhat; Mizuno, Takeshi; Muruganathan, Manoharan; Anh, Le The; Mizuta, Hiroshi; Nuryadi, Ratno; Moraru, Daniel

2016-01-01

We study low-temperature transport properties of two-dimensional (2D) Si tunnel diodes, or Si Esaki diodes, with a lateral layout. In ordinary Si Esaki diodes, interband tunneling current is severely limited because of the law of momentum conservation, while nanoscale Esaki diodes may behave differently due to the dopants in the narrow depletion region, by atomistic effects which release such current limitation. In thin-Si lateral highly doped pn diodes, we find clear signatures of interband tunneling between 2D-subbands involving phonon assistance. More importantly, the tunneling current is sharply enhanced in a narrow voltage range by resonance via a pair of a donor- and an acceptor-atom in the pn junction region. Such atomistic behavior is recognized as a general feature showing up only in nanoscale tunnel diodes. In particular, a donor-acceptor pair with deeper ground-state energies is likely to be responsible for such a sharply enhanced current peak, tunable by external biases.

Neural network feedforward control of a closed-circuit wind tunnel

Science.gov (United States)

Sutcliffe, Peter

Accurate control of wind-tunnel test conditions can be dramatically enhanced using feedforward control architectures which allow operating conditions to be maintained at a desired setpoint through the use of mathematical models as the primary source of prediction. However, as the desired accuracy of the feedforward prediction increases, the model complexity also increases, so that an ever increasing computational load is incurred. This drawback can be avoided by employing a neural network that is trained offline using the output of a high fidelity wind-tunnel mathematical model, so that the neural network can rapidly reproduce the predictions of the model with a greatly reduced computational overhead. A novel neural network database generation method, developed through the use of fractional factorial arrays, was employed such that a neural network can accurately predict wind-tunnel parameters across a wide range of operating conditions whilst trained upon a highly efficient database. The subsequent network was incorporated into a Neural Network Model Predictive Control (NNMPC) framework to allow an optimised output schedule capable of providing accurate control of the wind-tunnel operating parameters. Facilitation of an optimised path through the solution space is achieved through the use of a chaos optimisation algorithm such that a more globally optimum solution is likely to be found with less computational expense than the gradient descent method. The parameters associated with the NNMPC such as the control horizon are determined through the use of a Taguchi methodology enabling the minimum number of experiments to be carried out to determine the optimal combination. The resultant NNMPC scheme was employed upon the Hessert Low Speed Wind Tunnel at the University of Notre Dame to control the test-section temperature such that it follows a pre-determined reference trajectory during changes in the test-section velocity. Experimental testing revealed that the

Fracturing of hard rocks by microwave treatment and potential applications in mechanised tunnelling

OpenAIRE

YANLONG ZHENG

2018-01-01

Extremely hard and abrasive rocks have posed great challenges to mechanical excavators such as tunnel boring machines and roadheaders by increasing the cutter wear and decreasing the penetration rates. Microwave treatment prior to mechanical rock breakage has been recognised as a promising technology. This PhD project measures/derives the dielectric properties of commonly encountered rocks and minerals and investigates the effect of microwave treatment on the physical and mechanical propertie...

Design study of flat belt CVT for electric vehicles

Science.gov (United States)

Kumm, E. L.

1980-01-01

A continuously variable transmission (CVT) was studied, using a novel flat belt pulley arrangement which couples the high speed output shaft of an energy storage flywheel to the drive train of an electric vehicle. A specific CVT arrangement was recommended and its components were selected and sized, based on the design requirements of a 1700 KG vehicle. A design layout was prepared and engineering calculations made of component efficiencies and operating life. The transmission efficiency was calculated to be significantly over 90% with the expected vehicle operation. A design consistent with automotive practice for low future production costs was considered, together with maintainability. The technology advancements required to develop the flat belt CVT were identified and an estimate was made of how the size of the flat belt CVT scales to larger and smaller design output torques. The suitability of the flat belt CVT for alternate application to an electric vehicle powered by an electric motor without flywheel and to a hybrid electric vehicle powered by an electric motor with an internal combustion engine was studied.

Race, belief in destiny, and seat belt usage: a pilot study.

Science.gov (United States)

Colón, I

1992-01-01

A survey of 1063 individuals found that when belief in destiny was statistically controlled, differences in seat belt use by race disappeared. Thus, racial differences in seat belt use are statistically accounted for and might be explained by belief in destiny. Efforts to increase seat belt use should target minority groups rather than include them in broadbrush programs. Further, these efforts should take into account this important difference in motivation. PMID:1585969

Probability of Boulders

DEFF Research Database (Denmark)

Ditlevsen, Ove Dalager

1997-01-01

To collect background information for formulating a description of the expected soil properties along the tunnel line, in 1987 Storebælt initiated a statistical investigation of the occurrence and size of boulders in the Great Belt area. The data for the boulder size distribution were obtained....... The data collection part of the investigation was made on the basis of geological expert advice (Gunnar Larsen, Århus) by the Danish Geotechnical Institute (DGI).The statistical data analysis combined with stochastic modeling based on geometry and sound wave diffraction theory gave a point estimate...

Quantum tunneling with friction

Science.gov (United States)

Tokieda, M.; Hagino, K.

2017-05-01

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

INCAS TRISONIC WIND TUNNEL

Directory of Open Access Journals (Sweden)

Florin MUNTEANU

2009-09-01

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

A minimalistic and optimized conveyor belt for neutral atoms.

Science.gov (United States)

Roy, Ritayan; Condylis, Paul C; Prakash, Vindhiya; Sahagun, Daniel; Hessmo, Björn

2017-10-20

Here we report of a design and the performance of an optimized micro-fabricated conveyor belt for precise and adiabatic transportation of cold atoms. A theoretical model is presented to determine optimal currents in conductors used for the transportation. We experimentally demonstrate a fast adiabatic transportation of Rubidium ( 87 Rb) cold atoms with minimal loss and heating with as few as three conveyor belt conductors. This novel design of a multilayered conveyor belt structure is fabricated in aluminium nitride (AlN) because of its outstanding thermal and electrical properties. This demonstration would pave a way for a compact and portable quantum device required for quantum information processing and sensors, where precise positioning of cold atoms is desirable.

In-mine (tunnel-to-tunnel) electrical resistance tomography in South African platinum mines

CSIR Research Space (South Africa)

Van Schoor, Abraham M

2009-12-01

Full Text Available The applicability of tunnel-to-tunnel electrical resistance tomography (ERT) for imaging disruptive geological structures ahead of mining, in an igneous platinum mining environment is assessed. The geophysical targets of interest are slump...

Design of a nucleonic conveyor belt weighing machine

International Nuclear Information System (INIS)

Magal, B.S.; Sunder Singh, V.P.

1979-01-01

A brief literature survey of the existing conventional units and the nucleonic belt weigher is made. The design of a 250 ton per hour coal weighing unit working in conjunction with a 24 inch wide belt, running at 350 feet per minute has been attempted and a unit has been built to the above specifications. Caseium-137 line source has been used as an isotope and a 10 litre volume argon filled ionisation chamber has been used as a detector. A line source has been preferred to a point source. The unit is under trial and the accuracy of the same is being evaluated by changing the variables like particle size profile of the material deposited on the belt and sudden changes in loading. Initial trials indicate that an accuracy of +- 1 p.c. can be achieved. (auth.)

Destructive quantum interference in spin tunneling problems

OpenAIRE

von Delft, Jan; Henley, Christopher L.

1992-01-01

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

Knowledge, attitude and use of seat belt among commercial drivers in Sokoto Metropolis

Directory of Open Access Journals (Sweden)

A O Abiola

2010-01-01

Conclusion: This study has identified high level of knowledge, positive attitude and reported use of seat belt. It is recommended that public awareness of the safety benefits of seat belts and strong enforcement are necessary to achieve optimal use of seat belt.

Snow and ice blocking of tunnels

Energy Technology Data Exchange (ETDEWEB)

Lia, Leif

1998-12-31

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

A multi points ultrasonic detection method for material flow of belt conveyor

Science.gov (United States)

Zhang, Li; He, Rongjun

2018-03-01

For big detection error of single point ultrasonic ranging technology used in material flow detection of belt conveyor when coal distributes unevenly or is large, a material flow detection method of belt conveyor is designed based on multi points ultrasonic counter ranging technology. The method can calculate approximate sectional area of material by locating multi points on surfaces of material and belt, in order to get material flow according to running speed of belt conveyor. The test results show that the method has smaller detection error than single point ultrasonic ranging technology under the condition of big coal with uneven distribution.

The behavioral impact of an advertising campaign to promote safety belt use.

Science.gov (United States)

Cope, J G; Moy, S S; Grossnickle, W F

1988-01-01

Safety belt use was observed at one restaurant during McDonald's "Make It Click" promotional campaign. Following baseline, the program was monitored without intervention. During the final 2 weeks of the campaign an incentive strategy was added providing a large soft drink contingent on safety belt use. Safety belt use did not change from baseline levels before the incentive phase. The rate of belt use increased under contingent reward and declined during follow-up. The effects of a verbal prompt could not be assessed because of the almost nonexistent use of the "Make It Click" stickers throughout the study.

Study on Fuzzy Comprehensive Evaluation Model for the Safety of Mine Belt Conveyor

Directory of Open Access Journals (Sweden)

Gong Xiaoyan

2017-01-01

Full Text Available To improve the situation of the frequent failures of mine belt conveyor during operation, a model was used to evaluate the safety of mine belt conveyor. Based on the foundation of collecting and analyzing a large quantity of fault information of belt conveyor in the nationwide coal mine, the fault tree model of belt conveyor has been built, then the safety evaluation index system was established by analyzing and removing some secondary indicators. Furthermore, the weighted value of safety evaluation indexs was determined by analytic hierarchy process(AHP, and the single factor fuzzy evaluation matrix was constructed by experts grading method. Additionally, the model was applied in evaluating the security of belt conveyor in Nanliang coal mine. The results shows the security level is recognized to the “general”, which means that this model can be adopted widely in evaluating the safety of mine belt conveyor.

Investigation of Corner Effect and Identification of Tunneling Regimes in L-Shaped Tunnel Field-Effect-Transistor.

Science.gov (United States)

Najam, Faraz; Yu, Yun Seop

2018-09-01

Corner-effect existing in L-shaped tunnel field-effect-transistor (LTFET) was investigated using numerical simulations and band diagram analysis. It was found that the corner-effect is caused by the convergence of electric field in the sharp source corner present in an LTFET, thereby increasing the electric field in the sharp source corner region. It was found that in the corner-effect region tunneling starts early, as a function of applied bias, as compared to the rest of the channel not affected by corner-effect. Further, different tunneling regimes as a function of applied bias were identified in the LTFET including source to channel and channel to channel tunneling regimes. Presence of different tunneling regimes in LTFET was analytically justified with a set of equations developed to model source to channel, and channel to channel tunneling currents. Drain-current-gate-voltage (Ids-Vgs) characteristics obtained from the equations is in reasonable qualitative agreement with numerical simulation.

Does unbelted safety requirement affect protection for belted occupants?

Science.gov (United States)

Hu, Jingwen; Klinich, Kathleen D; Manary, Miriam A; Flannagan, Carol A C; Narayanaswamy, Prabha; Reed, Matthew P; Andreen, Margaret; Neal, Mark; Lin, Chin-Hsu

2017-05-29

Federal regulations in the United States require vehicles to meet occupant performance requirements with unbelted test dummies. Removing the test requirements with unbelted occupants might encourage the deployment of seat belt interlocks and allow restraint optimization to focus on belted occupants. The objective of this study is to compare the performance of restraint systems optimized for belted-only occupants with those optimized for both belted and unbelted occupants using computer simulations and field crash data analyses. In this study, 2 validated finite element (FE) vehicle/occupant models (a midsize sedan and a midsize SUV) were selected. Restraint design optimizations under standardized crash conditions (U.S.-NCAP and FMVSS 208) with and without unbelted requirements were conducted using Hybrid III (HIII) small female and midsize male anthropomorphic test devices (ATDs) in both vehicles on both driver and right front passenger positions. A total of 10 to 12 design parameters were varied in each optimization using a combination of response surface method (RSM) and genetic algorithm. To evaluate the field performance of restraints optimized with and without unbelted requirements, 55 frontal crash conditions covering a greater variety of crash types than those in the standardized crashes were selected. A total of 1,760 FE simulations were conducted for the field performance evaluation. Frontal crashes in the NASS-CDS database from 2002 to 2012 were used to develop injury risk curves and to provide the baseline performance of current restraint system and estimate the injury risk change by removing the unbelted requirement. Unbelted requirements do not affect the optimal seat belt and airbag design parameters in 3 out of 4 vehicle/occupant position conditions, except for the SUV passenger side. Overall, compared to the optimal designs with unbelted requirements, optimal designs without unbelted requirements generated the same or lower total injury risks for

Scanning Tunneling Optical Resonance Microscopy

Science.gov (United States)

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

2003-01-01

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

Fiber coupled ultrafast scanning tunneling microscope

DEFF Research Database (Denmark)

Keil, Ulrich Dieter Felix; Jensen, Jacob Riis; Hvam, Jørn Märcher

1997-01-01

We report on a scanning tunneling microscope with a photoconductive gate in the tunneling current circuit. The tunneling tip is attached to a coplanar transmission line with an integrated photoconductive switch. The switch is illuminated through a fiber which is rigidly attached to the switch...... waveguide. The measurements show that the probe works as a transient voltage detector in contact and a capacitively coupled transient field detector in tunneling mode. We do not measure the transient voltage change in the ohmic tunneling current. In this sense, the spatial resolution for propagating...... substrate. By using a firmly attached fiber we achieve an excellent reproducibility and unconstrained positioning of the tip. We observe a transient signal with 2.9 ps pulse width in tunneling mode and 5 ps in contact mode. The instrument is applied to investigating the mode structure on a coplanar...

Experimental Evidence for Quantum Tunneling Time

Science.gov (United States)

Camus, Nicolas; Yakaboylu, Enderalp; Fechner, Lutz; Klaiber, Michael; Laux, Martin; Mi, Yonghao; Hatsagortsyan, Karen Z.; Pfeifer, Thomas; Keitel, Christoph H.; Moshammer, Robert

2017-07-01

The first hundred attoseconds of the electron dynamics during strong field tunneling ionization are investigated. We quantify theoretically how the electron's classical trajectories in the continuum emerge from the tunneling process and test the results with those achieved in parallel from attoclock measurements. An especially high sensitivity on the tunneling barrier is accomplished here by comparing the momentum distributions of two atomic species of slightly deviating atomic potentials (argon and krypton) being ionized under absolutely identical conditions with near-infrared laser pulses (1300 nm). The agreement between experiment and theory provides clear evidence for a nonzero tunneling time delay and a nonvanishing longitudinal momentum of the electron at the "tunnel exit."

Tunneling from the past horizon

Science.gov (United States)

Kang, Subeom; Yeom, Dong-han

2018-04-01

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

Electronic tunneling through a potential barrier on the surface of a topological insulator

Science.gov (United States)

Zhou, Benliang; Zhou, Benhu; Zhou, Guanghui

2016-12-01

We investigate the tunneling transport for electrons on the surface of a topological insulator (TI) through an electrostatic potential barrier. By using the Dirac equation with the continuity conditions for all segments of wave functions at the interfaces between regions inside and outside the barrier, we calculate analytically the transmission probability and conductance for the system. It is demonstrated that, the Klein paradox can also been observed in the system same as in graphene system. Interestingly, the conductance reaches the minimum value when the incident electron energy is equal to the barrier strength. Moreover, with increasing barrier width, the conductance turns up some tunneling oscillation peaks, and larger barrier strength can cause lower conductance, shorter period but larger oscillation amplitude. The oscillation amplitude decreases as the barrier width increases, which is similar as that of the system consisting of the compressive uniaxial strain applied on a TI, but somewhat different from that of graphene system where the oscillation amplitude is a constant. The findings here imply that an electrostatic barrier can greatly influence the electron tunneling transport of the system, and may provide a new way to realize directional filtering of electrons.

Supersonic and transonic Mach probe for calibration control in the Trisonic Wind Tunnel

Directory of Open Access Journals (Sweden)

Alexandru Marius PANAIT

2017-12-01

Full Text Available A supersonic and high speed transonic Pitot Prandtl is described as it can be implemented in the Trisonic Wind Tunnel for calibration and verification of Mach number precision. A new calculation method for arbitrary precision Mach numbers is proposed and explained. The probe is specially designed for the Trisonic wind tunnel and would greatly simplify obtaining a precise Mach calibration in the critical high transonic and low supersonic regimes, where typically wind tunnels exhibit poor performance. The supersonic Pitot Prandtl combined probe is well known in the aerospace industry, however the proposed probe is a derivative of the standard configuration, combining a stout cone-cylinder probe with a supersonic Pitot static port which allows this configuration to validate the Mach number by three methods: conical flow method – using the pressure ports on a cone generatrix, the Schlieren-optical method of shock wave angle photogrammetry and the Rayleigh supersonic Pitot equation, while having an aerodynamic blockage similar to that of a scaled rocket model commonly used in testing. The proposed probe uses an existing cone-cylinder probe forebody and support, adding only an afterbody with a support for a static port.

Molecular series-tunneling junctions.

Science.gov (United States)

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

2015-05-13

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

Belt of Yotvings. Radioecology

International Nuclear Information System (INIS)

Mazheika, J.; Petroshius, R.; Strzelecki, R.; Wolkovitcz, S.; Lewandowski, P.

1997-01-01

Full text: The map of gamma radiation dose of 'Belt of Yotvings' area displays the summarized gamma radiation coming from natural radionuclides of 238 U, 232 Th, 40 K and from cesium isotopes 137 Cs, 134 Cs, artificially supplied into the environment after the Chernobyl disaster. The average value of gamma radiation dose for 'Belt of Yotvings' area is 44.2 n Gy/h, with a distinct regional differentiation. The content of uranium varies from 0 to 4.5 g/t, with the average value of about 1.4 g/t. Thorium content varies from 0 to 10.3 g/t, with the average value of 4.3 g/t. Potassium content varies from 0.1 up to 2.5 %, with the average value of 1.2 %. The concentration of caesium radioisotopes reaches up to 11.6 kBq/m 2 , the average value being 3.8 kBq/m 2 . Radon concentration in soil air has been determined in 55 sites (83 analyses). Radon concentration has been noticed in volumes from trace amounts up to 55 kBq/m3.The radioecological mapping has documented that the highest concentrations of natural radioisotopes and, correspondingly, the highest total gamma radiation dose were observed in the northeastern part of the area studied, which is covered by clay-silty glaciolacustrine deposits. Slightly lower values are typical for the whole northwestern part of 'Belt of Yotvings'. Very low contents of radioactive elements and low total radiation doses are typical for eolian and sandur sands, occurring south-eastward from the line Augustow-Veisiejai. The Chernobyl NPP accident polluted the studied region with artificial cesium radioisotopes un significantly. The concentrations are low and they involve no radioecological hazard. The investigation of radon concentration in soil air have revealed several places affected by high radon emanation. These places should be studied in a more detailed way

Araguaia fold belt, new geochronological data

International Nuclear Information System (INIS)

Lafon, J.M.; Macambira, J.B.; Macambira, M.J.B.; Moura, C.A.V.; Souza, A.C.C.

1990-01-01

The northern part of the Araguaia Fold Belt (AFB) outcrops in a N-S direction for about 400 km in the state of Tocantins. Dome-like structures occur in this fold belt also in a N-S direction. Both deformation and metamorphism increase from the West to the East. The basement of the AFB consist of Colmeia complex and Cantao gneiss, which crop out mainly in the core of the dome-like structures. The supracrustals rocks of the fold belt belongs to the Baixo Araguaia supergroup which is divided into the lower Estrondo group and the upper Tocantins group. Preliminary Sm-Nd data from the Colmeia complex (Grota Rica dome) gave Archean model ages of 2.8 Ga (TNd sub(DM)) while Rb-Sr data in the same rocks give an age of 2530 ± 200 Ma. In the others dome-like structures, the Rb-Sr systematics gave ages for the Colmeia a complex of 2239 ± 47 Ma (Colmeia structure) and 1972 ± 46 Ma (Lontra structure). These younger ages are believed to represent partial to total isotopic resetting of the Rb-Sr system during the Transamazonian Event. The Rb-Sr studies of the Cantao gneiss gave an age of 1774 ± 31 Ma. (author)

Automated Boundary Conditions for Wind Tunnel Simulations

Science.gov (United States)

Carlson, Jan-Renee

2018-01-01

Computational fluid dynamic (CFD) simulations of models tested in wind tunnels require a high level of fidelity and accuracy particularly for the purposes of CFD validation efforts. Considerable effort is required to ensure the proper characterization of both the physical geometry of the wind tunnel and recreating the correct flow conditions inside the wind tunnel. The typical trial-and-error effort used for determining the boundary condition values for a particular tunnel configuration are time and computer resource intensive. This paper describes a method for calculating and updating the back pressure boundary condition in wind tunnel simulations by using a proportional-integral-derivative controller. The controller methodology and equations are discussed, and simulations using the controller to set a tunnel Mach number in the NASA Langley 14- by 22-Foot Subsonic Tunnel are demonstrated.

FUNDAMENTAL TUNNELING PROCESSES IN MOSa SOLAR CELLS

OpenAIRE

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

1981-01-01

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

Survival of Listeria monocytogenes on a conveyor belt material with or without antimicrobial additives.

Science.gov (United States)

Chaitiemwong, N; Hazeleger, W C; Beumer, R R

2010-08-15

Survival of Listeria monocytogenes on a conveyor belt material with or without antimicrobial additives, in the absence or presence of food debris from meat, fish and vegetables and at temperatures of 10, 25 and 37 degrees C was investigated. The pathogen survived best at 10 degrees C, and better at 25 degrees C than at 37 degrees C on both conveyor belt materials. The reduction in the numbers of the pathogen on belt material with antimicrobial additives in the first 6h at 10 degrees C was 0.6 log unit, which was significantly higher (Padditives. Reductions were significantly less (Pfood residue. At 37 degrees C and 20% relative humidity, large decreases in the numbers of the pathogen on both conveyor belt materials during the first 6h were observed. Under these conditions, there was no obvious effect of the antimicrobial substances. However, at 25 degrees C and 10 degrees C and high humidity (60-75% rh), a rapid decrease in bacterial numbers on the belt material with antimicrobial substances was observed. Apparently the reduction in numbers of L. monocytogenes on belt material with antimicrobial additives was greater than on belt material without additives only when the surfaces were wet. Moreover, the presence of food debris neutralized the effect of the antimicrobials. The results suggest that the antimicrobial additives in conveyor belt material could help to reduce numbers of microorganisms on belts at low temperatures when food residues are absent and belts are not rapidly dried. Copyright 2010 Elsevier B.V. All rights reserved.

A Computerized Tomography Study of Vocal Tract Setting in Hyperfunctional Dysphonia and in Belting.

Science.gov (United States)

Saldias, Marcelo; Guzman, Marco; Miranda, Gonzalo; Laukkanen, Anne-Maria

2018-04-03

Vocal tract setting in hyperfunctional patients is characterized by a high larynx and narrowing of the epilaryngeal and pharyngeal region. Similar observations have been made for various singing styles, eg, belting. The voice quality in belting has been described to be loud, speech like, and high pitched. It is also often described as sounding "pressed" or "tense". The above mentioned has led to the hypothesis that belting may be strenuous to the vocal folds. However, singers and teachers of belting do not regard belting as particularly strenuous. This study investigates possible similarities and differences between hyperfunctional voice production and belting. This study concerns vocal tract setting. Four male patients with hyperfunctional dysphonia and one male contemporary commercial music singer were registered with computerized tomography while phonating on [a:] in their habitual speaking pitch. Additionally, the singer used the pitch G4 in belting. The scannings were studied in sagittal and transversal dimensions by measuring lengths, widths, and areas. Various similarities were found between belting and hyperfunction: high vertical larynx position, small hypopharyngeal width, and epilaryngeal outlet. On the other hand, belting differed from dysphonia (in addition to higher pitch) by a wider lip and jaw opening, and larger volumes of the oral cavity. Belting takes advantage of "megaphone shape" of the vocal tract. Future studies should focus on modeling and simulation to address sound energy transfer. Also, they should consider aerodynamic variables and vocal fold vibration to evaluate the "price of decibels" in these phonation types. Copyright © 2018. Published by Elsevier Inc.

The Baltic haline conveyor belt or the overturning circulation and mixing in the Baltic.

Science.gov (United States)

Döös, Kristofer; Meier, H E Markus; Döscher, Ralf

2004-06-01

A study of the water-mass circulation of the Baltic has been undertaken by making use of a three dimensional Baltic Sea model simulation. The saline water from the North Atlantic is traced through the Danish Sounds into the Baltic where it upwells and mixes with the fresh water inflow from the rivers forming a Baltic haline conveyor belt. The mixing of the saline water from the Great Belt and Oresund with the fresh water is investigated making use of overturning stream functions and Lagrangian trajectories. The overturning stream function was calculated as a function of four different vertical coordinates (depth, salinity, temperature and density) in order to understand the path of the water and where it upwells and mixes. Evidence of a fictive depth overturning cell similar to the Deacon Cell in the Southern Ocean was found in the Baltic proper corresponding to the gyre circulation around Gotland, which vanishes when the overturning stream function is projected on density layers. A Lagrangian trajectory study was performed to obtain a better view of the circulation and mixing of the saline and fresh waters. The residence time of the water masses in the Baltic is calculated to be 26-29 years and the Lagrangian dispersion reaches basin saturation after 5 years.

Distribution of tunnelling times for quantum electron transport

International Nuclear Information System (INIS)

Rudge, Samuel L.; Kosov, Daniel S.

2016-01-01

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

Using naturalistic driving data to identify variables associated with infrequent, occasional, and consistent seat belt use.

Science.gov (United States)

Reagan, Ian J; McClafferty, Julie A; Berlin, Sharon P; Hankey, Jonathan M

2013-01-01

Seat belt use is one of the most effective countermeasures to reduce traffic fatalities and injuries. The success of efforts to increase use is measured by road side observations and self-report questionnaires. These methods have shortcomings, with the former requiring a binary point estimate and the latter being subjective. The 100-car naturalistic driving study presented a unique opportunity to study seat belt use in that seat belt status was known for every trip each driver made during a 12-month period. Drivers were grouped into infrequent, occasional, or consistent seat belt users based on the frequency of belt use. Analyses were then completed to assess if these groups differed on several measures including personality, demographics, self-reported driving style variables as well as measures from the 100-car study instrumentation suite (average trip speed, trips per day). In addition, detailed analyses of the occasional belt user group were completed to identify factors that were predictive of occasional belt users wearing their belts. The analyses indicated that consistent seat belt users took fewer trips per day, and that increased average trip speed was associated with increased belt use among occasional belt users. The results of this project may help focus messaging efforts to convert occasional and inconsistent seat belt users to consistent users. Copyright © 2012 Elsevier Ltd. All rights reserved.

Een systeem voor classificatie van korte tunnels.

NARCIS (Netherlands)

Schreuder, D.A.

1985-01-01

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

Effects of the finite duration of quantum tunneling in laser-assisted scanning tunneling microscopy

International Nuclear Information System (INIS)

Hagmann, M.J.

1994-01-01

Previous measurements of tunnel conductance in heterostructures and experiments with Josephson junctions suggest quantum tunneling has a definite duration. The authors use semiclassical methods to determine the effects of this delay on the tunneling current in a laser-assisted STM. A planar-planar STM model is used with the exact multiple image potential, and the energy distribution for a free-electron metal. It is necessary to average over the phase at barrier entry, and iteration with back propagated solutions is required to obtain the transmission coefficients for evenly spaced phases and specified energies at barrier entry. The simulations suggest that the dependence of the tunneling current on the wavelength of illumination can serve as a basis for determining the duration of barrier traversal. A power flux density of 10 11 W/m 2 would be required at several wavelengths from 1 to 10 μm. It is possible that thermal effects could be separated from the modeled phenomena by determining the time dependence of the tunneling current with a pulsed laser

Dependences of the Tunnel Magnetoresistance and Spin Transfer Torque on the Sizes and Concentration of Nanoparticles in Magnetic Tunnel Junctions

Science.gov (United States)

Esmaeili, A. M.; Useinov, A. N.; Useinov, N. Kh.

2018-01-01

Dependences of the tunnel magnetoresistance and in-plane component of the spin transfer torque on the applied voltage in a magnetic tunnel junction have been calculated in the approximation of ballistic transport of conduction electrons through an insulating layer with embedded magnetic or nonmagnetic nanoparticles. A single-barrier magnetic tunnel junction with a nanoparticle embedded in an insulator forms a double-barrier magnetic tunnel junction. It has been shown that the in-plane component of the spin transfer torque in the double-barrier magnetic tunnel junction can be higher than that in the single-barrier one at the same thickness of the insulating layer. The calculations show that nanoparticles embedded in the tunnel junction increase the probability of tunneling of electrons, create resonance conditions, and ensure the quantization of the conductance in contrast to the tunnel junction without nanoparticles. The calculated dependences of the tunnel magnetoresistance correspond to experimental data demonstrating peak anomalies and suppression of the maximum magnetoresistances at low voltages.

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.

1998-10-01

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.)

Pilot-scale continuous ultrasonic cleaning equipment reduces Listeria monocytogenes levels on conveyor belts.

Science.gov (United States)

Tolvanen, Riina; Lundén, Janne; Hörman, Ari; Korkeala, Hannu

2009-02-01

Ultrasonic cleaning of a conveyor belt was studied by building a pilot-scale conveyor with an ultrasonic cleaning bath. A piece of the stainless steel conveyor belt was contaminated with meat-based soil and Listeria monocytogenes strains (V1, V3, and B9) and incubated for 72 h to allow bacteria to attach to the conveyor belt surfaces. The effect of ultrasound with a potassium hydroxide-based cleaning detergent was determined by using the cleaning bath at 45 and 50 degrees C for 30 s with and without ultrasound. The detachment of L. monocytogenes from the conveyor belt caused by the ultrasonic treatment was significantly greater at 45 degrees C (independent samples t test, P conveyor belt is effective even with short treatment times.

Motivating signage prompts safety belt use among drivers exiting senior communities.

Science.gov (United States)

Cox, B S; Cox, A B; Cox, D J

2000-01-01

Senior drivers are vulnerable to automobile crashes and subsequent injury and death. Safety belts reduce health risks associated with auto crashes. Therefore, it is important to encourage senior drivers to wear safety belts while driving. Using an AB design, replicated five times, we evaluated the short- and long-term effects of a sign with the message "BUCKLE UP, STAY SAFE" attached to a stop sign at the exits of five different senior communities. Safety belt use was stable during two pretreatment assessments averaged across the five sites and 250 drivers (72% and 68% usage), but significantly increased following installation of these signs (94% usage). Six months after installation of the signs, the effect persisted (88% usage). Use of such signs may be a cost-effective way of promoting safety belt use.

Synthetic approaches to aromatic belts: building up strain in macrocyclic polyarenes.

Science.gov (United States)

Eisenberg, David; Shenhar, Roy; Rabinovitz, Mordecai

2010-08-01

This tutorial review discusses synthetic strategies towards aromatic belts, defined here as double-stranded conjugated macrocycles, such as [n]cyclacenes, [n]cyclophenacenes, Schlüter belt, and Vögtle belt. Their appeal stems, firstly, from the unique nature of their conjugation, having p orbitals oriented radially rather than perpendicular to the plane of the macrocycle. Secondly, as aromatic belts are model compounds of carbon nanotubes of different chiralities, a synthetic strategy towards the buildup of structural strain in these compounds could finally open a route towards rational chemical synthesis of carbon nanotubes. The elusiveness of these compounds has stimulated fascinating and ingenious synthetic strategies over the last decades. The various strategies are classified here by their approach to the buildup of structural strain, which is the main obstacle in the preparation of these curved polyarenes.

Strain-enhanced tunneling magnetoresistance in MgO magnetic tunnel junctions.

Science.gov (United States)

Loong, Li Ming; Qiu, Xuepeng; Neo, Zhi Peng; Deorani, Praveen; Wu, Yang; Bhatia, Charanjit S; Saeys, Mark; Yang, Hyunsoo

2014-09-30

While the effects of lattice mismatch-induced strain, mechanical strain, as well as the intrinsic strain of thin films are sometimes detrimental, resulting in mechanical deformation and failure, strain can also be usefully harnessed for applications such as data storage, transistors, solar cells, and strain gauges, among other things. Here, we demonstrate that quantum transport across magnetic tunnel junctions (MTJs) can be significantly affected by the introduction of controllable mechanical strain, achieving an enhancement factor of ~2 in the experimental tunneling magnetoresistance (TMR) ratio. We further correlate this strain-enhanced TMR with coherent spin tunneling through the MgO barrier. Moreover, the strain-enhanced TMR is analyzed using non-equilibrium Green's function (NEGF) quantum transport calculations. Our results help elucidate the TMR mechanism at the atomic level and can provide a new way to enhance, as well as tune, the quantum properties in nanoscale materials and devices.

Trap assisted tunneling and its effect on subthreshold swing of tunnel field effect transistors

OpenAIRE

Sajjad, Redwan N.; Chern, Winston; Hoyt, Judy L.; Antoniadis, Dimitri A.

2016-01-01

We provide a detailed study of the interface Trap Assisted Tunneling (TAT) mechanism in tunnel field effect transistors to show how it contributes a major leakage current path before the Band To Band Tunneling (BTBT) is initiated. With a modified Shockley-Read-Hall formalism, we show that at room temperature, the phonon assisted TAT current always dominates and obscures the steep turn ON of the BTBT current for common densities of traps. Our results are applicable to top gate, double gate and...

78 FR 46117 - National Tunnel Inspection Standards

Science.gov (United States)

2013-07-30

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

Tunneling magnetoresistance and electroresistance in Fe/PbTiO{sub 3}/Fe multiferroic tunnel junctions

Energy Technology Data Exchange (ETDEWEB)

Dai, Jian-Qing, E-mail: djqkust@sina.com [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

2016-08-21

We perform first-principles electronic structure and spin-dependent transport calculations for a Fe/PbTiO{sub 3}/Fe multiferroic tunnel junction with asymmetric TiO{sub 2}- and PbO-terminated interfaces. We demonstrate that the interfacial electronic reconstruction driven by the in situ screening of ferroelectric polarization, in conjunction with the intricate complex band structure of barrier, play a decisive role in controlling the spin-dependent tunneling. Reversal of ferroelectric polarization results in a transition from insulating to half-metal-like conducting state for the interfacial Pb 6p{sub z} orbitals, which acts as an atomic-scale spin-valve by releasing the tunneling current in antiparallel magnetization configuration as the ferroelectric polarization pointing to the PbO-terminated interface. This effect produces large change in tunneling conductance. Our results open an attractive avenue in designing multiferroic tunnel junctions with excellent performance by exploiting the interfacial electronic reconstruction originated from the in situ screening of ferroelectric polarization.

Resolving the planetesimal belt of HR 8799 with ALMA

Science.gov (United States)

Booth, Mark; Jordán, Andrés; Casassus, Simon; Hales, Antonio S.; Dent, William R. F.; Faramaz, Virginie; Matrà, Luca; Barkats, Denis; Brahm, Rafael; Cuadra, Jorge

2016-07-01

The star HR 8799 hosts one of the largest known debris discs and at least four giant planets. Previous observations have found evidence for a warm belt within the orbits of the planets, a cold planetesimal belt beyond their orbits and a halo of small grains. With the infrared data, it is hard to distinguish the planetesimal belt emission from that of the grains in the halo. With this in mind, the system has been observed with ALMA in band 6 (1.34 mm) using a compact array format. These observations allow the inner edge of the planetesimal belt to be resolved for the first time. A radial distribution of dust grains is fitted to the data using an MCMC method. The disc is best fitted by a broad ring between 145^{+12}_{-12} au and 429^{+37}_{-32} au at an inclination of 40^{+5}_{-6}° and a position angle of 51^{+8}_{-8}°. A disc edge at ˜145 au is too far out to be explained simply by interactions with planet b, requiring either a more complicated dynamical history or an extra planet beyond the orbit of planet b.

Tunnel nitrogen spill experiment

International Nuclear Information System (INIS)

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

1983-01-01

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

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

Science.gov (United States)

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

2018-04-01

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

An Auto-Tuning PI Control System for an Open-Circuit Low-Speed Wind Tunnel Designed for Greenhouse Technology.

Science.gov (United States)

Espinoza, Karlos; Valera, Diego L; Torres, José A; López, Alejandro; Molina-Aiz, Francisco D

2015-08-12

Wind tunnels are a key experimental tool for the analysis of airflow parameters in many fields of application. Despite their great potential impact on agricultural research, few contributions have dealt with the development of automatic control systems for wind tunnels in the field of greenhouse technology. The objective of this paper is to present an automatic control system that provides precision and speed of measurement, as well as efficient data processing in low-speed wind tunnel experiments for greenhouse engineering applications. The system is based on an algorithm that identifies the system model and calculates the optimum PI controller. The validation of the system was performed on a cellulose evaporative cooling pad and on insect-proof screens to assess its response to perturbations. The control system provided an accuracy of integrated software unit that manages the tests in terms of airflow speed and pressure drop set points.

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

Science.gov (United States)

Demagh, Rafik; Emeriault, Fabrice

2013-06-01

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

Design of dual energy x-ray detector for conveyor belt with steel wire ropes

Science.gov (United States)

Dai, Yue; Miao, Changyun; Rong, Feng

2009-07-01

A dual energy X-ray detector for conveyor belt with steel wire ropes is researched in the paper. Conveyor belt with steel wire ropes is one of primary transfer equipments in modern production. The traditional test methods like electromagnetic induction principle could not display inner image of steel wire ropes directly. So X-ray detection technology has used to detect the conveyor belt. However the image was not so clear by the interference of the rubber belt. Therefore, the dualenergy X-ray detection technology with subtraction method is developed to numerically remove the rubber belt from radiograph, thus improving the definition of the ropes image. The purpose of this research is to design a dual energy Xray detector that could make the operator easier to found the faulty of the belt. This detection system is composed of Xray source, detector controlled by FPGA chip, PC for running image processing system and so on. With the result of the simulating, this design really improved the capability of the staff to test the conveyor belt.

Seat-belt use still low in Kuwait: self-reported driving behaviours among adult drivers.

Science.gov (United States)

Raman, Sudha R; Ottensmeyer, C Andrea; Landry, Michel D; Alfadhli, Jarrah; Procter, Steven; Jacob, Susan; Hamdan, Elham; Bouhaimed, Manal

2014-01-01

Kuwait mandated seat-belt use by drivers in 1976 and by front seat passengers in 1994. The study objectives were to identify and estimate current factors associated with seat-belt use and levels of potentially unsafe driving behaviours in Kuwait. In 2010, 741 adults were surveyed regarding driving habits and history. Only 41.6% of drivers reported always using a seat belt. Front seat passenger belt use was more common (30.5%) than rear seat belt use (6.5%). Distracted driving behaviours were common, including mobile phone use ('always' or 'almost always': 51.1%) and texting/SMS (32.4%). Logistic regression indicated that drivers who were young (18-19 years), male, Kuwaiti nationals or non-Kuwaiti Arabs, drove over the speed limit, had traffic violation tickets or >1 car crashes in the last year, were less likely to use seat belts. Targeted initiatives to increase public awareness and to enforce car-safety legislation, including use of seat belts, are necessary to decrease the health burden of car crashes in Kuwait.

Tunneling Flight Time, Chemistry, and Special Relativity.

Science.gov (United States)

Petersen, Jakob; Pollak, Eli

2017-09-07

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

A belt charging system for the Vivitron - design, early results

International Nuclear Information System (INIS)

Helleboid, J.M.; Gaudiot, G.

1990-10-01

A specific belt charging system has been designed, built and assembled for the 35 MV Vivitron. 100 m long belt is used. Together with main features of the design, experimental studies, tests in a pilot machine and the results of the very early tests of the real system are reviewed

Respiratory Belt Transducer Constructed Using a Singing Greeting Card Beeper

Science.gov (United States)

Bhaskar, Anand; Subramani, Selvam; Ojha, Rajdeep

2013-01-01

An article by Belusic and Zupancic described the construction of a finger pulse sensor using a singing greeting card beeper. These authors felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers,…

Tunnel Face Stability & New CPT Applications

NARCIS (Netherlands)

Broere, W.

2001-01-01

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

Upper limit on the inner radiation belt MeV electron intensity

Science.gov (United States)

Li, X; Selesnick, RS; Baker, DN; Jaynes, AN; Kanekal, SG; Schiller, Q; Blum, L; Fennell, J; Blake, JB

2015-01-01

No instruments in the inner radiation belt are immune from the unforgiving penetration of the highly energetic protons (tens of MeV to GeV). The inner belt proton flux level, however, is relatively stable; thus, for any given instrument, the proton contamination often leads to a certain background noise. Measurements from the Relativistic Electron and Proton Telescope integrated little experiment on board Colorado Student Space Weather Experiment CubeSat, in a low Earth orbit, clearly demonstrate that there exist sub-MeV electrons in the inner belt because their flux level is orders of magnitude higher than the background, while higher-energy electron (>1.6 MeV) measurements cannot be distinguished from the background. Detailed analysis of high-quality measurements from the Relativistic Electron and Proton Telescope on board Van Allen Probes, in a geo-transfer-like orbit, provides, for the first time, quantified upper limits on MeV electron fluxes in various energy ranges in the inner belt. These upper limits are rather different from flux levels in the AE8 and AE9 models, which were developed based on older data sources. For 1.7, 2.5, and 3.3 MeV electrons, the upper limits are about 1 order of magnitude lower than predicted model fluxes. The implication of this difference is profound in that unless there are extreme solar wind conditions, which have not happened yet since the launch of Van Allen Probes, significant enhancements of MeV electrons do not occur in the inner belt even though such enhancements are commonly seen in the outer belt. Key Points Quantified upper limit of MeV electrons in the inner belt Actual MeV electron intensity likely much lower than the upper limit More detailed understanding of relativistic electrons in the magnetosphere PMID:26167446

Direct detection of albedo neutron decay electrons at the inner edge of the radiation belt and experimental determination of neutron density in near-Earth space

Science.gov (United States)

Li, X.; Selesnick, R.; Schiller, Q. A.; Zhang, K.; Zhao, H.; Baker, D. N.; Temerin, M. A.

2017-12-01

The galaxy is filled with cosmic ray particles, mostly protons with kinetic energy above hundreds of mega-electron volts (MeV). Soon after the discovery of Earth's Van Allen radiation belts almost six decades ago, it was recognized that the main source of inner belt protons, with kinetic energies of tens to hundreds of MeV, is Cosmic Ray Albedo Neutron Decay (CRAND). In this process, cosmic rays reaching the upper atmosphere from throughout the galaxy interact with neutral atoms to produce albedo neutrons which, being unstable to 𝛽 decay, are a potential source of geomagnetically trapped protons and electrons. Protons retain most of the neutrons' kinetic energy while the electrons have lower energies, mostly below 1 MeV. The viability of the electron source was, however, uncertain because measurements showed that electron intensity can vary greatly while the neutron decay rate should be almost constant. Recent measurements from the Relativistic Electron and Proton Telescope integrated little experiment (REPTile) onboard the Colorado Student Space Weather Experiment (CSSWE) CubeSat now show that CRAND is the main electron source for the radiation belt near its inner edge, and also contributes to the inner belt elsewhere. Furthermore, measurement of the CRAND electron intensity provides the first experimental determination of the neutron density in near-Earth space, 2x10-9/cm3, confirming earlier theoretical estimates.

The effectiveness of automatic belts in reducing fatality rates in Toyota Cressidas.

Science.gov (United States)

Nash, C E

1989-12-01

Toyota Cressidas have had motor driven automatic belts since 1981. Their observed use rates have been consistently close to 100%. This paper compares fatality rates in Toyota Cressidas with those in the similar Nissan Maximas (which are equipped with three-point manual belts) using the latest data from the Fatal Accident Reporting System. After making adjustments for differences in the average ages of front seat occupants of the two fleets, the Toyotas have a fatality rate that is about three-quarters that of the Nissans. From this, the fatality-reducing effectiveness for the Toyota automatic belts is estimated to be 40% with an uncertainty of +/- 8%. This effectiveness estimate is consistent with earlier estimates of automatic belt effectiveness.

Fall Protection Characteristics of Safety Belts and Human Impact Tolerance.

Science.gov (United States)

Hino, Yasumichi; Ohdo, Katsutoshi; Takahashi, Hiroki

2014-08-23

Many fatal accidents due to falls from heights have occurred at construction sites not only in Japan but also in other countries. This study aims to determine the fall prevention performance of two types of safety belts: a body belt 1) , which has been used for more than 40 yr in the Japanese construction industry as a general type of safety equipment for fall accident prevention, and a full harness 2, 3) , which has been used in many other countries. To determine human tolerance for impact trauma, this study discusses features of safety belts with reference 4-9) to relevant studies in the medical science, automobile crash safety, and aircrew safety. For this purpose, simple drop tests were carried out in a virtual workplace to measure impact load, head acceleration, and posture in the experiments, the Hybrid-III pedestrian model 10) was used as a human dummy. Hybrid-III is typically employed in official automobile crash tests (New Car Assessment Program: NCAP) and is currently recognized as a model that faithfully reproduces dynamic responses. Experimental results shows that safety performance strongly depends on both the variety of safety belts used and the shock absorbers attached onto lanyards. These findings indicate that fall prevention equipment, such as safety belts, lanyards, and shock absorbers, must be improved to reduce impact injuries to the human head and body during falls.

THE SURFACE COMPOSITION OF LARGE KUIPER BELT OBJECT 2007 OR10

International Nuclear Information System (INIS)

Brown, M. E.; Fraser, W. C.; Burgasser, A. J.

2011-01-01

We present photometry and spectra of the large Kuiper belt object 2007 OR10. The data show significant near-infrared absorption features due to water ice. While most objects in the Kuiper belt with water ice absorption this prominent have the optically neutral colors of water ice, 2007 OR10 is among the reddest Kuiper belt objects known. One other large Kuiper belt object-Quaoar-has similar red coloring and water ice absorption, and it is hypothesized that the red coloration of this object is due to irradiation of the small amounts of methane able to be retained on Quaoar. 2007 OR10, though warmer than Quaoar, is in a similar volatile retention regime because it is sufficiently larger that its stronger gravity can still retain methane. We propose, therefore, that the red coloration on 2007 OR10 is also caused by the retention of small amounts of methane. Positive detection of methane on 2007 OR10 will require spectra with higher signal to noise. Models for volatile retention on Kuiper belt objects appear to continue to do an excellent job reproducing all of the available observations.

Shaft and tunnel sealing considerations

International Nuclear Information System (INIS)

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

1980-01-01

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

Low temperature ultrahigh vacuum cross-sectional scanning tunneling microscope for luminescence measurements

International Nuclear Information System (INIS)

Khang, Yoonho; Park, Yeonjoon; Salmeron, Miquel; Weber, Eicke R.

1999-01-01

We have constructed a scanning tunneling microscope with simultaneous light collection capabilities in order to investigate the opto-electronic properties of semiconductors. The microscope has in situ sample cleavage mechanism for cross-sectional sample. In order to reach low temperature (4 K), we used a specially designed cryostat. The efficiency of light collection generated in the tip-surface junction was greatly improved by use of a small parabolic mirror with the tip located at its focal point. (c) 1999 American Institute of Physics

Computational Multiqubit Tunnelling in Programmable Quantum Annealers

Science.gov (United States)

2016-08-25

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

Evaluation of the Influence Caused by Tunnel Construction on Groundwater Environment: A Case Study of Tongluoshan Tunnel, China

Directory of Open Access Journals (Sweden)

Jian Liu

2015-01-01

Full Text Available Problems related to water inflow during tunnel construction are challenging to designers, workers, and management departments, as they can threaten tunneling project from safety, time, and economic aspects. Identifying the impacts on groundwater environment resulting from tunnel drainage and making a correct assessment before tunnel construction is essential to better understand troubles that would be encountered during tunnel excavation and helpful to adopt appropriate countermeasures to minimize the influences. This study presents an indicator system and quantifies each indicator of Tongluoshan tunnel, which is located in southwest China with a length of 5.2 km and mainly passes through carbonate rocks and sandstones, based on field investigation and related technological reports. Then, an evaluation is made using fuzzy comprehensive assessment method, with a result showing that it had influenced the local groundwater environment at a moderate degree. Information fed back from environmental investigation and hydrologic monitoring carried out during the main construction period proves the evaluation, as the flow of some springs and streams located beside the tunnel route was found experiencing an apparent decline.

Investigation into scanning tunnelling luminescence microscopy

International Nuclear Information System (INIS)

Manson-Smith, S.K.

2001-01-01

This work reports on the development of a scanning tunnelling luminescence (STL) microscope and its application to the study of Ill-nitride semiconductor materials used in the production of light emitting devices. STL microscopy is a technique which uses the high resolution topographic imaging capabilities of the scanning tunnelling microscope (STM) to generate high resolution luminescence images. The STM tunnelling current acts as a highly localised source of electrons (or holes) which generates luminescence in certain materials. Light generated at the STM tunnelling junction is collected concurrently with the height variation of the tunnelling probe as it is scanned across a sample surface, producing simultaneous topographic and luminescence images. Due to the very localised excitation source, high resolution luminescence images can be obtained. Spectroscopic resolution can be obtained by using filters. Additionally, the variation of luminescence intensity with tunnel current and with bias voltage can provide information on recombination processes and material properties. The design and construction of a scanning tunnelling luminescence microscope is described in detail. Operating under ambient conditions, the microscope has several novel features, including a new type of miniature inertial slider-based approach motor, large solid-angle light collection optical arrangement and a tip-height regulation system which requires the minimum of operator input. (author)

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.

1998-02-01

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.)

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

International Nuclear Information System (INIS)

Miyazaki, Tetsuo; Aratono, Yasuyuki; Ichikawa, Tsuneki; Shiotani, Masaru

1998-02-01

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.)

Tunneling anisotropic magnetoresistance in Co/AIOx/Al tunnel junctions with fcc Co (111) electrodes

NARCIS (Netherlands)

Wang, Kai; Tran, T. Lan Ahn; Brinks, Peter; Brinks, P.; Sanderink, Johannes G.M.; Bolhuis, Thijs; van der Wiel, Wilfred Gerard; de Jong, Machiel Pieter

2013-01-01

Tunneling anisotropic magnetoresistance (TAMR) has been characterized in junctions comprised of face-centered cubic (fcc) Co (111) ferromagnetic electrodes grown epitaxially on sapphire substrates, amorphous AlOx tunnel barriers, and nonmagnetic Al counterelectrodes. Large TAMR ratios have been

Radiation Belts of Antiparticles in Planetary Magnetospheres

Science.gov (United States)

Pugacheva, G. I.; Gusev, A. A.; Jayanthi, U. B.; Martin, I. M.; Spjeldvik, W. N.

2007-05-01

The Earth's radiation belts could be populated, besides with electrons and protons, also by antiparticles, such as positrons (Basilova et al., 1982) and antiprotons (pbar). Positrons are born in the decay of pions that are directly produced in nuclear reactions of trapped relativistic inner zone protons with the residual atmosphere at altitudes in the range of about 500 to 3000 km over the Earth's surface. Antiprotons are born by high energy (E > 6 GeV) cosmic rays in p+p - p+p+p+ pbar and in p+p - p+p+n+nbar reactions. The trapping and storage of these charged anti-particles in the magnetosphere result in radiation belts similar to the classical Van Allen belts of protons and electrons. We describe the mathematical techniques used for numerical simulation of the trapped positron and antiproton belt fluxes. The pion and antiproton yields were simulated on the basis of the Russian nuclear reaction computer code MSDM, a Multy Stage Dynamical Model, Monte Carlo code, (i.e., Dementyev and Sobolevsky, 1999). For estimates of positron flux there we have accounted for ionisation, bremsstrahlung, and synchrotron energy losses. The resulting numerical estimates show that the positron flux with energy >100 MeV trapped into the radiation belt at L=1.2 is of the order ~1000 m-2 s-1 sr-1, and that it is very sensitive to the shape of the trapped proton spectrum. This confined positron flux is found to be greater than that albedo, not trapped, mixed electron/positron flux of about 50 m-2 s-1 sr-1 produced by CR in the same region at the top of the geomagnetic field line at L=1.2. As we show in report, this albedo flux also consists mostly of positrons. The trapped antiproton fluxes produced by CR in the Earth's upper rarified atmosphere were calculated in the energy range from 10 MeV to several GeV. In the simulations we included a mathematic consideration of the radial diffusion process, both an inner and an outer antiproton source, losses of particles due to ionization process

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

International Nuclear Information System (INIS)

Takeuchi, Kunifumi

1994-01-01

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

49 CFR 571.209 - Standard No. 209; Seat belt assemblies.

Science.gov (United States)

2010-10-01

... seat belt assembly to fit the user, including such hardware that may be integral with a buckle... the proper use of the assembly, stressing particularly the importance of wearing the assembly snugly... of Standard No. 208. (a)(1) A manual seat belt assembly, which is subject to the requirements of S5.1...

Resonance tunneling electron-vibrational spectroscopy of polyoxometalates.

Science.gov (United States)

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

2017-05-21

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

Current noise in tunnel junctions