driven rail gun: Topics by Science.gov

Sample records for driven rail gun

Energy partitioning in an inductively driven rail gun

NASA Technical Reports Server (NTRS)

Sen, K. K.; Ray, P. K.

1984-01-01

The equations describing the performance of an inductively driven rail are analyzed numerically. Friction between the projectile and rails is included through an empirical formulation. The equations are applied to the experiment of Rashleigh and Marshall to obtain an estimate of energy distribution in rail guns as a function of time. It is found that only 15 percent of energy delivered by the inductor to the gun is transformed into the kinetic energy of the projectile. This study provides an insight into the nature of nonlinear coupling involved in the electromechanical interactions in a rail gun.
Arc-driven rail gun research

NASA Technical Reports Server (NTRS)

Ray, P. K.

1984-01-01

The equations describing the performance of an inductively-driven rail gun are analyzed numerically. Friction between the projectile and rails is included through an empirical formulation. The equations are applied to the experiment of Rashleigh and Marshall to obtain an estimate of energy distribution in rail guns as a function of time. The effect of frictional heat dissipation on the bore of the gun is calculated. The mechanism of plasma and projectile acceleration in a dc rail gun is described from a microscopic point of view through the establishment of the Hall field. The plasma conductivity is shown to be a tensor indicating that there is a small component of current parallel to the direction of acceleration. The plasma characteristics are evaluated as a function of plasma mass through a simple fluid mechanical analysis of the plasma. By equating the energy dissipated in the plasma with the radiation heat loss, the properties of the plasma are determined.
Friction in rail guns

NASA Technical Reports Server (NTRS)

Kay, P. K.

1984-01-01

The influence of friction is included in the present equations describing the performance of an inductively driven rail gun. These equations, which have their basis in an empirical formulation, are applied to results from two different experiments. Only an approximate physical description of the problem is attempted, in view of the complexity of details in the interaction among forces of this magnitude over time periods of the order of milisecs.
Pulse Power Applications of Flux Compression Generators

DTIC Science & Technology

1981-06-01

Characteristics are presented for two different types of explosive driven flux compression generators and a megavolt pulse transformer. Status reports are given for rail gun and plasma focus programs for which the generators serve as power sources.
Rail damage in a solid-armature rail gun. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brassard, T.; Homan, C.G.

1987-12-01

Plasma-arc-drive rail guns operate by forming a high-temperature plasma behind the projectile using a thin metal fuze. These systems achieve the highest projectile velocities (about 12 km /sec), since the driving force includes a substantial plasma pressure as well as the electromagnetic or Lorentz force. Unfortunately, severe rail damage occurs primarily from the intense temperatures generated by the plasma arc and the wiping motion of the armature itself. The solid-armature gun replaces the plasma armature with a conducting metal armature. Since the plasma arcing is reduced or eliminated, the projectiles are accelerated mainly by the Lorentz force. Thus, solid armaturemore » rail guns operate at lower projectile velocities. The important tradeoff is that there is a substantial reduction in rail damage for metal armature projectiles. The elimination of the plasma force limits projectile velocities in the metal-armature rail guns. A more-subtle limit is the speed at which the commutation process can take place. Although the latter limit is still not well understood, experimental evidence indicates a commutation limit may occur near 6 to 7 km/sec. This velocity limit is still attractive for Army tactical missions for rail guns. The actual rail damage occurring with two types of metal armatures, wire brush contactors and monolithic metal contactors, and new developments in barrel technology, such as superconducting augmentation, are presented in this report.« less
Plasma Dynamics of the Arc-Driven Rail Gun

DTIC Science & Technology

1980-09-01

Authors’ unpublished calculations. 11. A.B. Cambel , Plasma Physics and Magnetofluidmechanics (McGraw-Hill New York, 1963), Chap. 8. ’ 16 k T P = (1 +cO...Energy, and Forces (Wiley, New York, 1960), Chap. 9. 10. Authors’ unpublished calculations. 11. A.B. Cambel , Plasma Physics and Magnetofluidmechanics
The electric rail gun for space propulsion

NASA Technical Reports Server (NTRS)

Bauer, D. P.; Barber, J. P.; Vahlberg, C. J.

1981-01-01

An analytic feasibility investigation of an electric propulsion concept for space application is described. In this concept, quasistatic thrust due to inertial reaction to repetitively accelerated pellets by an electric rail gun is used to propel a spacecraft. The study encompasses the major subsystems required in an electric rail gun propulsion system. The mass, performance, and configuration of each subsystem are described. Based on an analytic model of the system mass and performance, the electric rail gun mission performance as a reusable orbital transfer vehicle (OTV) is analyzed and compared to a 30 cm ion thruster system (BIMOD) and a chemical propulsion system (IUS) for payloads with masses of 1150 kg and 2300 kg. For system power levels in the range from 25 kW(e) to 100 kW(e) an electric rail gun OTV is more attractive than a BIMOD system for low Earth orbit to geosynchronous orbit transfer durations in the range from 20 to 120 days.
Investigation of the residue in an electric rail gun employing a plasma armature

NASA Technical Reports Server (NTRS)

Bauer, D. P.; Barber, J. P.

1984-01-01

The performance of dc electric rail guns using plasma-armature-accelerated projectiles was studied. It was found that the initial rail launcher acceleration profile was consistent with the simulation, but that after the projectile had traveled approximately 25 to 30 cm along the gun, a considerable portion of the current in the projectile armature commutated into a secondary current path. Also noted were the lower than expected muzzle velocities. It was proposed that the secondary current path was a relatively high conductivity layer of residue on the launcher bore.
Low voltage arc formation in railguns

DOEpatents

Hawke, R.S.

1985-08-05

A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.
Low voltage arc formation in railguns

DOEpatents

Hawke, Ronald S.

1987-01-01

A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.
Low voltage arc formation in railguns

DOEpatents

Hawke, R.S.

1987-11-17

A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile. 2 figs.
Advanced concepts. [specific impulse, mass drivers, electromagnetic launchers, and the rail gun

NASA Technical Reports Server (NTRS)

Banks, B. A.

1980-01-01

The relative strengths of those interactions which enable propulsive forces are listed as well as the specific impulse of various propellants. Graphics show the linear synchronous motor of the mass driver, the principle of the direct current electromagnetic launcher, and the characteristics of the rail gun.
Possible application of electromagnetic guns to impact fusion

NASA Astrophysics Data System (ADS)

Kostoff, R. N.; Peaslee, A. T., Jr.; Ribe, F. L.

1982-01-01

The possible application of electromagnetic guns to impact fusion for the generation of electric power is discussed, and advantages of impact fusion over the more conventional inertial confinement fusion concepts are examined. It is shown that impact fusion can achieve the necessary high yields, of the order of a few gigajoules, which are difficult to achieve with lasers except at unrealistically high target gains. The rail gun accelerator is well adapted to the delivery of some 10-100 megajoules of energy to the fusion target, and the electrical technology involved is relatively simple: inductive storage or rotating machinery and capacitors. It is concluded that the rail gun has the potential of developing into an impact fusion macroparticle accelerator.
Direct launch using the electric rail gun

NASA Technical Reports Server (NTRS)

Barber, J. P.

1983-01-01

The concept explored involves using a large single stage electric rail gun to achieve orbital velocities. Exit aerodynamics, launch package design and size, interior ballistics, system and component sizing and design concepts are treated. Technology development status and development requirements are identified and described. The expense of placing payloads in Earth orbit using conventional chemical rockets is considerable. Chemical rockets are very inefficient in converting chemical energy into payload kinetic energy. A rocket motor is relatively expensive and is usually expended on each launch. In addition specialized and expensive forms of fuel are required. Gun launching payloads directly to orbit from the Earth's surface is a possible alternative. Guns are much more energy efficient than rockets. The high capital cost of the gun installation can be recovered by reusing it over and over again. Finally, relatively inexpensive fuel and large quantities of energy are readily available to a fixed installation on the Earth's surface.
Shock-wave facility at Tokyo Institute of Technology

NASA Astrophysics Data System (ADS)

Sawaoka, A.; Kondo, K.

1982-04-01

The shock-wave facility at the Tokyo Institute of Technology is described. Two double-stage light-gas guns are used to studying material science and technology. Recently construction has begun for a new type of rail gun combined with a double-stage light-gas gun.
The analysis and modeling of the ARDEC 2.5 km/s 20-mm plasma railgun shot

NASA Astrophysics Data System (ADS)

Sink, D. A.; Chang, D. I.; Davis, A.; Colombo, G.; Hildenbrand, D. J.

1993-01-01

The 20-mm round-bore plasma railgun was successfully fired at the ARDEC electric gun facility. The 4-m gun with copper rails and alumina composite insulators was operated using a light-gas gun injector to start the projectile, already located in the gun, moving prior to the introduction of current. Current from the EMACK homopolar generator (HPG) was commutated into the gun by an explosively-actuated opening switch. The muzzle velocity was recorded by breakwires and flash X-rays at 2.5 km/s. B-dot sensors, rail current Rogowski coils, and breech and muzzle voltage measurements provided data on the in-bore dynamics of the armature. Post-shot analysis using the ARMRAIL (ARMature Physics and RAILgun Performance Model) code successfully provided calculations reproducing all the main features of the data. Models account for the observed secondary arcs present throughout the shot and the basis for the code and physics modeling is given.
Characterisation of plasma in a rail gun

NASA Technical Reports Server (NTRS)

Ray, P. K.

1986-01-01

The mechanism of plasma and projectile acceleration in a DC rail gun is described from a microscopic point of view through the establishment of the Hall field. The plasma conductivity is shown to be a tensor, indicating that there is a small component of current parallel to the direction of acceleration. The plasma characteristics are evaluated in the experiment of Bauer et. al., as a function of plasma mass through a simple fluid mechanical analysis of the plasma. By equating the energy dissipatated in the plasma with the radiation heat loss, the properties of the plasma are determined.
Navy Lasers, Railgun, and Hypervelocity Projectile: Background and Issues for Congress

DTIC Science & Technology

2016-03-18

1 Railgun is also spelled as rail gun ; EMRG is also abbreviated as EM railgun; hypervelocity is also...controlled Gatling gun . Employing all these measures reflects a long-standing Navy approach of creating a multi-layered defense against enemy...fact that Navy surface ships can use surface-to-air missiles (SAMs) and their Close-in Weapon System (CIWS) Gatling guns to shoot down only a certain
Electric rail gun projectile acceleration to high velocity

NASA Technical Reports Server (NTRS)

Bauer, D. P.; Mccormick, T. J.; Barber, J. P.

1982-01-01

Electric rail accelerators are being investigated for application in electric propulsion systems. Several electric propulsion applications require that the rail accelerator be capable of launching projectiles at velocities above 10 km/s. An experimental program was conducted to develop rail accelerator technology for high velocity projectile launch. Several 6 mm bore, 3 m long rail accelerators were fabricated. Projectiles with a mass of 0.2 g were accelerated by plasmas, carrying currents up to 150 kA. Experimental design and results are described. Results indicate that the accelerator performed as predicted for a fraction of the total projectile acceleration. The disparity between predicted and measured results are discussed.
Role of the leader in the rail gun channel at high launching velocities

NASA Astrophysics Data System (ADS)

Zagorskii, A. V.; Katsnel'Son, S. S.; Pravdin, S. S.; Fomichev, V. P.

1992-08-01

An analysis of the performance of a number of rail guns indicates that one of the factors limiting the launching velocity is the formation of a leader. In experiments, the leader is usually formed as a result of a plasma breakdown between the dielectric projectile and the channel walls. This can be prevented by various technical means. However, at high launching velocities (5 km/s and greater) a leader may form as a result of a breakdown in the ionized gas in the wake of a strong shock wave ahead of the projectile. Further research is needed to find ways of preventing the formation of a leader in the latter case.

Design of a Rail Gun System for Mitigating Disruptions in Fusion Reactors

NASA Astrophysics Data System (ADS)

Lay, Wei-Siang

Magnetic fusion devices, such as the tokamak, that carry a large amount of current to generate the plasma confining magnetic fields have the potential to lose magnetic stability control. This can lead to a major plasma disruption, which can cause most of the stored plasma energy to be lost to localized regions on the walls, causing severe damage. This is the most important issue for the $20B ITER device (International Thermonuclear Experimental Reactor) that is under construction in France. By injecting radiative materials deep into the plasma, the plasma energy could be dispersed more evenly on the vessel surface thus mitigating the harmful consequences of a disruption. Methods currently planned for ITER rely on the slow expansion of gases to propel the radiative payloads, and they also need to be located far away from the reactor vessel, which further slows down the response time of the system. Rail guns are being developed for aerospace applications, such as for mass transfer from the surface of the moon and asteroids to low earth orbit. A miniatured version of this aerospace technology seems to be particularly well suited to meet the fast time response needs of an ITER disruption mitigation system. Mounting this device close to the reactor vessel is also possible, which substantially increases its performance because the stray magnetic fields near the vessel walls could be used to augment the rail gun generated magnetic fields. In this thesis, the potential viability on Rail Gun based DMS is studied to investigate its projected fast time response capability by design, fabrication, and experiment of an NSTX-U sized rail gun system. Material and geometry based tests are used to find the most suitable armature design for this system for which the desirable attributes are high specific stiffness and high electrical conductivity. With the best material in these studies being aluminum 7075, the experimental Electromagnetic Particle Injector (EPI) system has propelled an aluminum armature (weighing 3g) to a velocity more than 150 m/s within two milliseconds post trigger, consistent with the predicted projection for a system with those parameters. Fixed magnetic field probes and high-speed images capture the velocity profile. To propel the armatures, a 20 mF capacitor bank charged to 2 kV and augmented with external field coils powers the rails. These studies indicate that an EPI based system can indeed operate with a fast response time of less than three milliseconds after an impending disruption is detected, and thus warrants further studies to more fully develop the concept as a back-up option for an ITER DMS.
Efficiency equations of the railgun

NASA Astrophysics Data System (ADS)

Sadedin, D. R.

1984-03-01

The feasibility of an employment of railguns for large scale applications, such as space launching, will ultimately be determined by efficiency considerations. The present investigation is concerned with the calculation of the efficiencies for constant current railguns. Elementary considerations are discussed, taking into account a simple condition for high efficiency, the magnetic field of the rails, and the acceleration force on the projectile. The loss in a portion of the rails is considered along with rail loss comparisons, applications to the segmented gun, rail losses related to the constant resistance per unit length, efficiency expressions, and arc, or muzzle voltage energy.
Comparison of Two Railgun Power Supply Architectures to Quantify the Energy Dissipated After the Projectile Leaves the Railgun

DTIC Science & Technology

2016-06-01

inch gun on impact [1]. The potential of the EM railgun renders the need to store dangerous explosives associated with the conventional warheads...leaves the gun . The simulation will outline some critical performance characteristics of a buck-boost power supply as compared to a thyristor-based...between the rails and from the projectile position along the length of the gun x [5]: 3 1 2 𔃻 2 2 w o
A gasdynamic gun driven by gaseous detonation

NASA Astrophysics Data System (ADS)

Li, Jinping; Chen, Hong; Zhang, Shizhong; Zhang, Xiaoyuan; Yu, Hongru

2016-01-01

A gasdynamic gun driven by gaseous detonation was developed to address the disadvantages of the insufficient driving capability of high-pressure gas and the constraints of gunpowder. The performance of this gasdynamic gun was investigated through experiments and numerical simulations. Much more powerful launching capability was achieved by this gun relative to a conventional high-pressure gas gun, owing to the use of the chemical energy of the driver gas. To achieve the same launching condition, the initial pressure required for this gun was an order of magnitude lower than that for a gun driven by high-pressure H2. Because of the presence of the detonation, however, a more complex internal ballistic process of this gun was observed. Acceleration of projectiles for this gun was accompanied by a series of impulse loads, in contrast with the smooth acceleration for a conventional one, which indicates that this gun should be used conditionally. The practical feasibility of this gun was verified by experiments. The experiments demonstrated the convenience of taking advantage of the techniques developed for detonation-driven shock tubes and tunnels.
Symposium on Electromagnetic Launcher Technology, 5th, Sandestin, FL, Apr. 3-5, 1990, Proceedings

NASA Astrophysics Data System (ADS)

Gooden, Clarence E.

1991-01-01

The present conference on electromagnetic accelerators (EMAs) and railguns (RGs) discusses active-current management for four-rail RGs, the design of a compulsator-drive 60-caliber RG, EMA studies with augmented rails, muzzle-shunt augmentation of conventional RGs, effect of in-bore gas on RG performance, the distributed-energy store RG, plasma diagnostics for high power ignitron development, a review of EMA armature research, RG hybrid armatures, a new solid-armature design concept, and the electrodynamics of RG plasma armatures. Also discussed is RG modeling at speed using three-dimensional finite elements, power supply technology for EMAs, rotating machine power supplies for next-generation EMAs, advanced EMA power supplies with magnetic-flux compression, metal-to-metal switches for large currents, lightweight high-effiency energy-storage transformers, hypervelocity projectile development for EMAs, structural design issues for EMA projectiles, stiff RGs, a reinforced Al conductor for cryogenic applications, mass-stabilized projectile designs for EMA launch, indictively-commutated coilguns, an actively switched pulsed induction accelerator, a plasma gun-augmented electrothermal accelerator, a symmetrical rail accelerator, and a travelling-wave synchronous coil gun.
Excitation Method of Linear-Motor-Type Rail Brake without Using Power Sources by Dynamic Braking with Zero Electrical Output

NASA Astrophysics Data System (ADS)

Sakamoto, Yasuaki; Kashiwagi, Takayuki; Hasegawa, Hitoshi; Sasakawa, Takashi; Fujii, Nobuo

The eddy current rail brake is a type of braking system used in railway vehicles. Because of problems such as rail heating and problems associated with ensuring that power is supplied when the feeder malfunctions, this braking system has not been used for practical applications in Japan. Therefore, we proposed the use of linear induction motor (LIM) technology in eddy current rail brake systems. The LIM rail brake driven by dynamic braking can reduce rail heating and generate the energy required for self-excitation. In this paper, we present an excitation system and control method for the LIM rail brake driven by “dynamic braking with zero electrical output”. The proposed system is based on the concept that the LIM rail brake can be energized without using excitation power sources such as a feeder circuit and that high reliability can be realized by providing an independent excitation system. We have studied this system and conducted verification tests using a prototype LIM rail brake on a roller rig. The results show that the system performance is adequate for commercializing the proposed system, in which the LIM rail brake is driven without using any excitation power source.
Basic Studies on Electro-Energetic Physics (EEP) Weapons Technologies

DTIC Science & Technology

2015-01-15

Po\\\\ered Microwa\\e. High Energ) Laser. Charged Particle Beams. and II) pcrsonic Rail guns . Using these representations. wargame simulations of’ arious...Projectile length = 30 in (76 cm) • Barrel length = 10 m • Muzzle velocity = 2,100 m/s To understand how such an advanced weapon compares with conventional...weaponry, it is illustrating to compare these figures with the M-1 Abrams M256 120mm gun firing a M829A1 kinetic energy round Page 5 • Muzzle
Analysis of Rail Gun Bore Residue

DTIC Science & Technology

1984-03-01

erosion effects and elemental analysis of refractory materials. C. A. L. Westerdahl , J. Pinto, G. L. Ferventino, D. N. Saherhavth...accelerator facility at Large Caliber Weapons Systems Laboratory Dover, New Jersey. ’ 16 REFERENCES 1. C.A.L. Westerdahl , J. Pinto, G. L. Ferrentino, D
Arc-Dynamic Calculations In The Rail Gun

DTIC Science & Technology

1983-11-01

16. C,A.L. Westerdahl , 1. Pinto, G,L, Ferrentino, T. Gora, ’Larse-Railsun Residue Material Photoelectron Spectroscopy,’ IEEE Trans. on (1983). D...8217 Ballistic Research Laboratory Report No. ARBRL-TR-02530, Oct 83. 15. J.D. Powell, private communication. • 16. C.A.L. Westerdahl , J. Pinto, G.L
16. OPERATOR STAND. OPERATOR STOOD BETWEEN RAILINGS AND CONTROLLED DREDGING ...

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

16. OPERATOR STAND. OPERATOR STOOD BETWEEN RAILINGS AND CONTROLLED DREDGING OPERATIONS USING TWO LEVERS FROM CEILING, THREE LEVELS ON THE FLOOR, AND TWO FLOOR PEDDLES. RIGHT HAND CONTROLLED SHOT GUN SWINGER (BOOM MOVE TO RIGHT WHEN PUSHED FORWARD, LEFT WHEN PULLED BACK, AND, IF LUCKY, STOPPED WHEN IN CENTER POSITION). LEFT HAND CONTROLLED THROTTLE. FLOOR LEVER AND FLOOR PEDDLE ON LEFT CONTROLLED THE BACKING LINE FRICTION. MIDDLE LEVER AND PEDDLE, STUCK IN FLOOR CONTROLLED THE MAIN HOIST FRICTION. LEVER ON RIGHT CONTROLLED THE CYLINDER DRAIN VALVE. - Dredge CINCINNATI, Docked on Ohio River at foot of Lighthill Street, Pittsburgh, Allegheny County, PA
Shock Equation of State of Multi-Phase Epoxy-Based Composite (Al-MnO2-Epoxy)

DTIC Science & Technology

2010-10-01

single stage light gas gun , two...using three different loading techniques— single stage light gas gun , two stage light gas gun , and explosive loading—with multiple diagnostic...wave speed. B. Single stage gas gun loading experiments Four gas gun -driven equation of state experiments were conducted at NSWC-Indian Head using
Characterization of advanced electric propulsion systems

NASA Technical Reports Server (NTRS)

Ray, P. K.

1982-01-01

Characteristics of several advanced electric propulsion systems are evaluated and compared. The propulsion systems studied are mass driver, rail gun, MPD thruster, hydrogen free radical thruster and mercury electron bombardment ion engine. These are characterized by specific impulse, overall efficiency, input power, average thrust, power to average thrust ratio and average thrust to dry weight ratio. Several important physical characteristics such as dry system mass, accelerator length, bore size and current pulse requirement are also evaluated in appropriate cases. Only the ion engine can operate at a specific impulse beyond 2000 sec. Rail gun, MPD thruster and free radical thruster are currently characterized by low efficiencies. Mass drivers have the best performance characteristics in terms of overall efficiency, power to average thrust ratio and average thrust to dry weight ratio. But, they can only operate at low specific impulses due to large power requirements and are extremely long due to limitations of driving current. Mercury ion engines have the next best performance characteristics while operating at higher specific impulses. It is concluded that, overall, ion engines have somewhat better characteristics as compared to the other electric propulsion systems.
Magnetic gauge instrumentation on the LANL gas-driven two-stage gun

NASA Astrophysics Data System (ADS)

Alcon, R. R.; Sheffield, S. A.; Martinez, A. R.; Gustavsen, R. L.

1998-07-01

The LANL gas-driven two-stage gun was designed and built to do initiation studies on insensitive high explosives as well as equation of state and reaction experiments on other materials. The preferred method of measuring reaction phenomena involves the use of in-situ magnetic particle velocity gauges. In order to accommodate this type of gauging in our two-stage gun, it has a 50-mm-diameter launch tube. We have used magnetic gauging on our 72-mm bore diameter single-stage gun for over 15 years and it has proven a very effective technique for all types of shock wave experiments, including those on high explosives. This technique has now been installed on our gas-driven two-stage gun. We describe the method used, as well as some of the difficulties that arose during the installation. Several magnetic gauge experiments have been completed on plastic materials. Waveforms obtained in some of the experiments will be discussed. Up to 10 in-situ particle velocity measurements can be made in a single experiment. This new technique is now working quite well, as is evidenced by the data. To our knowledge, this is the first time magnetic gauging has been used on a two-stage gun.
The HyperV 8000 μg, 50 km/s Plasma Railgun for PLX

NASA Astrophysics Data System (ADS)

Brockington, Samuel; Case, Andrew; Messer, Sarah; Wu, Linchun; Witherspoon, F. Douglas

2012-10-01

HyperV has developed a gas fed, pulsed, plasma railgun which accelerates 8000 μg of argon to 50 km/s meeting the performance requirements originally specified for the Plasma Liner Experiment (PLX). The present 2.5 cm square-bore plasma railgun forms plasma armatures from high density neutral gas, pre-ionizes it electro-thermally, and accelerates the armature with 30 cm long parallel-plate railgun electrodes driven by a pulse forming network (PFN). A high voltage, high current linear array spark-gap switch and flexible, low-inductance transmission line were designed and constructed to handle the increased current load. We will describe these systems and present initial performance data from high current operation of the plasma rail gun from spectroscopy, interferometry, and imaging systems. Measurements of momentum, pressure, magnetic field, and other optical diagnostics will also be discussed as well as plans for upcoming experimentation to increase performance even further. Work supported by USDOE under DE-FG02-05ER54810 and DE-FG02-08ER85114.
Dynamic Performance of Subway Vehicle with Linear Induction Motor System

NASA Astrophysics Data System (ADS)

Wu, Pingbo; Luo, Ren; Hu, Yan; Zeng, Jing

The light rail vehicle with Linear Induction Motor (LIM) bogie, which is a new type of urban rail traffic tool, has the advantages of low costs, wide applicability, low noise, simple maintenance and better dynamic behavior. This kind of vehicle, supported and guided by the wheel and rail, is not driven by the wheel/rail adhesion force, but driven by the electromagnetic force between LIM and reaction plate. In this paper, three different types of suspensions and their characteristic are discussed with considering the interactions both between wheel and rail and between LIM and reaction plate. A nonlinear mathematical model of the vehicle with LIM bogie is set up by using the software SIMPACK, and the electromechanical model is also set up on Simulink roof. Then the running behavior of the LIM vehicle is simulated, and the influence of suspension on the vehicle dynamic performance is investigated.
An ultrafast electron microscope gun driven by two-photon photoemission from a nanotip cathode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bormann, Reiner; Strauch, Stefanie; Schäfer, Sascha, E-mail: schaefer@ph4.physik.uni-goettingen.de

We experimentally and numerically investigate the performance of an advanced ultrafast electron source, based on two-photon photoemission from a tungsten needle cathode incorporated in an electron microscope gun geometry. Emission properties are characterized as a function of the electrostatic gun settings, and operating conditions leading to laser-triggered electron beams of very low emittance (below 20 nm mrad) are identified. The results highlight the excellent suitability of optically driven nano-cathodes for the further development of ultrafast transmission electron microscopy.
International Space Station-Based Electromagnetic Launcher for Space Science Payloads

NASA Technical Reports Server (NTRS)

Jones, Ross M.

2013-01-01

A method was developed of lowering the cost of planetary exploration missions by using an electromagnetic propulsion/launcher, rather than a chemical-fueled rocket for propulsion. An electromagnetic launcher (EML) based at the International Space Station (ISS) would be used to launch small science payloads to the Moon and near Earth asteroids (NEAs) for the science and exploration missions. An ISS-based electromagnetic launcher could also inject science payloads into orbits around the Earth and perhaps to Mars. The EML would replace rocket technology for certain missions. The EML is a high-energy system that uses electricity rather than propellant to accelerate payloads to high velocities. The most common type of EML is the rail gun. Other types are possible, e.g., a coil gun, also known as a Gauss gun or mass driver. The EML could also "drop" science payloads into the Earth's upper
Rail gun performance and plasma characteristics due to wall ablation

NASA Technical Reports Server (NTRS)

Ray, P. K.

1986-01-01

The experiment of Bauer, et al. (1982) is analyzed by considering wall ablation and viscous drag in the plasma. Plasma characteristics are evaluated through a simple fluid-mechanical analysis considering only wall ablation. By equating the energy dissipated in the plasma with the radiation heat loss, the average properties of the plasma are determined as a function of time.
Load Designs For MJ Dense Plasma Foci

NASA Astrophysics Data System (ADS)

Link, A.; Povlius, A.; Anaya, R.; Anderson, M. G.; Angus, J. R.; Cooper, C. M.; Falabella, S.; Goerz, D.; Higginson, D.; Holod, I.; McMahon, M.; Mitrani, J.; Koh, E. S.; Pearson, A.; Podpaly, Y. A.; Prasad, R.; van Lue, D.; Watson, J.; Schmidt, A. E.

2017-10-01

Dense plasma focus (DPF) Z-pinches are compact pulse power driven devices with coaxial electrodes. The discharge of DPF consists of three distinct phases: first generation of a plasma sheath, plasma rail gun phase where the sheath is accelerated down the electrodes and finally an implosion phase where the plasma stagnates into a z-pinch geometry. During the z-pinch phase, DPFs can produce MeV ion beams, x-rays and neutrons. Megaampere class DPFs with deuterium fills have demonstrated neutron yields in the 1012 neutrons/shot range with pulse durations of 10-100 ns. Kinetic simulations using the code Chicago are being used to evaluate various load configurations from initial sheath formation to the final z-pinch phase for DPFs with up to 5 MA and 1 MJ coupled to the load. Results will be presented from the preliminary design simulations. LLNL-ABS-734785 This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory (LLNL) under Contract DE-AC52-07NA27344 and with support from the Computing Grand Challenge program at LLNL.
The impact of the Orlando mass shooting on fear of victimization and gun-purchasing intentions: Not what one might expect.

PubMed

Stroebe, Wolfgang; Leander, N Pontus; Kruglanski, Arie W

2017-01-01

Mass public shootings are typically followed by a spike in gun sales as well as calls for stricter gun control laws. What remains unclear is whether the spike in gun sales is motivated by increased threat perceptions or by concerns about gun control, or whether the sales are mainly driven by non-owners purchasing guns or gun owners adding to their collection. Two surveys of gun owners and non-owners, conducted immediately before and after the Orlando shooting, allowed us to assess its impact on threat perceptions and on gun-purchasing intentions. Although there was a minor impact on threat perceptions of non-owners, neither group reported any increased gun-purchasing intentions or an increased need of a gun for protection and self-defense. We suggest that these responses are representative for the majority of Americans and, therefore, people who are influenced by mass shootings to buy guns are probably an atypical minority.

The impact of the Orlando mass shooting on fear of victimization and gun-purchasing intentions: Not what one might expect

PubMed Central

Stroebe, Wolfgang; Leander, N. Pontus; Kruglanski, Arie W.

2017-01-01

Mass public shootings are typically followed by a spike in gun sales as well as calls for stricter gun control laws. What remains unclear is whether the spike in gun sales is motivated by increased threat perceptions or by concerns about gun control, or whether the sales are mainly driven by non-owners purchasing guns or gun owners adding to their collection. Two surveys of gun owners and non-owners, conducted immediately before and after the Orlando shooting, allowed us to assess its impact on threat perceptions and on gun-purchasing intentions. Although there was a minor impact on threat perceptions of non-owners, neither group reported any increased gun-purchasing intentions or an increased need of a gun for protection and self-defense. We suggest that these responses are representative for the majority of Americans and, therefore, people who are influenced by mass shootings to buy guns are probably an atypical minority. PMID:28800365
16. THE INSTALLATION OF CONVEYORS AND OVERHEAD RAILS ELIMINATED THE ...

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

16. THE INSTALLATION OF CONVEYORS AND OVERHEAD RAILS ELIMINATED THE NEED TO LAY MOLDS OUT ON FLOORS AND HAND-POUR THEM. INSTEAD, WORKERS PULLED LARGE LADLES ALONG OVERHEAD RAILS AND FILLED CONVEYOR-DRIVEN MOLDS WHILE THEY STOOD ON A MOVING PLATFORM THAT TRAVELED AT THE SAME SPEED AS THE MOLD CONVEYOR, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL
Arc-driven rail accelerator research

NASA Technical Reports Server (NTRS)

Ray, Pradosh K.

1987-01-01

Arc-driven rail accelerator research is analyzed by considering wall ablation and viscous drag in the plasma. Plasma characteristics are evaluated through a simple fluid-mechanical analysis considering only wall ablation. By equating the energy dissipated in the plasma with the radiation heat loss, the average properties of the plasma are determined as a function of time and rate of ablation. Locations of two simultaneously accelerating arcs were determined by optical and magnetic probes and fron streak camera photographs. All three measurements provide consistent results.
Writing to Think: The Intellectual Journey of a Naval Career

DTIC Science & Technology

2014-02-01

progenitor, a clear intellectual audit trail winds through the developmental events, includ ing a war game and work- shops, to the published strategy. In...projected utility, it is still a gas- turbine - powered destroyer that employs chemical-based weapons. As the technologies of rail guns, electromagnetic...one off the Falklands in 1982, had there been sufficient wind for the Argentine carrier to launch its strike aircraft and had the aircraft then
Design and construction of a DC high-brightness laser driven electron gun

NASA Astrophysics Data System (ADS)

Zhao, K.; Geng, R. L.; Wang, L. F.; Zhang, B. C.; Yu, J.; Wang, T.; Wu, G. F.; Song, J. H.; Chen, J. E.

1996-02-01

A DC high-brightness laser driven photoemissive electron gun is being developed at Peking University, in order to produce 50-100 ps electron bunches of high quality. The gun consists of a photocathode preparation chamber and a DC acceleration cavity. Different ways of fabricating photocathodes, such as chemical vapor deposition, ion beam implantation and ion beam enhanced deposition, can be adopted. The acceleration gap is designed with the aid of simulation codes EGUN and POISSON. The laser system is a mode-locked Nd-YAG oscillator proceeded by an amplifier at 10 Hz repetition rate, which can deliver three different wavelengths (1064/532/266 nm). The combination of a superconducting cavity with the photocathode preparation chamber is also discussed in this paper.
Magnetic Gauge Instrumentation on the LANL Gas-Driven Two-Stage Gun

NASA Astrophysics Data System (ADS)

Alcon, R. R.; Sheffield, S. A.; Martinez, A. R.; Gustavsen, R. L.

1997-07-01

Our gas-driven two-stage gun was designed and built to do initiation studies on insensitive high explosives as well as other equation of state experiments on inert materials. Our preferred method of measuring initiation phenomena involves the use of in-situ magnetic particle velocity gauges. In order to provide the 1-D experimental area to accommodate this type of gauging in our two-stage gun, it has a 50-mm-diameter launch tube. We have used magnetic gauging on our 72-mm bore diameter single-stage gun for over 15 years and it has proven a very effective technique for all types of shock wave experiments, including those on high explosives. This technique has now been installed on our two-stage gun. We describe the experimental method, as well as some of the difficulties that arose during the installation. Several magnetic gauge experiments have been completed on plastic and high explosive materials. Waveforms obtained in some of the experiments will be discussed. Up to 10 in-situ particle velocity measurements can be made in a single experiment. This new technique is now working quite well, as is evidenced by the data. To our knowledge, this is the first time magnetic gauging has been used on a two-stage gun.
Femtosecond-laser-driven photoelectron-gun for time-resolved cathodoluminescence measurement of GaN.

PubMed

Onuma, T; Kagamitani, Y; Hazu, K; Ishiguro, T; Fukuda, T; Chichibu, S F

2012-04-01

A rear-excitation femtosecond-laser-driven photoelectron gun (PE-gun) is developed for measuring time-resolved cathodoluminescence (TRCL) spectrum of wide bandgap materials and structures such as semiconductors and phosphors. The maximum quantum efficiency of a 20-nm-thick Au photocathode excited using a frequency-tripled Al(2)O(3):Ti laser under a rear-excitation configuration is 3.6×10(-6), which is a reasonable value for a PE-gun. When the distance between the front edge of the PE-gun and the observation point is 10 mm, the narrowest electron-beam (e-beam) diameter is 19 μm, which corresponds to one tenth of the laser-beam diameter and is comparable to the initial e-beam diameter of a typical W hair-pin filament of thermionic electron-gun. From the results of TRCL measurements on the freestanding GaN grown by the ammonothermal method and a GaN homoepitaxial film grown by metalorganic vapor phase epitaxy, overall response time for the present TRCL system is estimated to be 8 ps. The value is the same as that of time-resolved photoluminescence measurement using the same excitation laser pulses, meaning that the time-resolution is simply limited by the streak-camera, not by the PE-gun performance. The result of numerical simulation on the temporal e-beam broadening caused by the space-charge-effect suggests that the present PE-gun can be used as a pulsed e-beam source for spatio-time-resolved cathodoluminescence, when equipped in a scanning electron microscope. © 2012 American Institute of Physics
Femtosecond-laser-driven photoelectron-gun for time-resolved cathodoluminescence measurement of GaN

NASA Astrophysics Data System (ADS)

Onuma, T.; Kagamitani, Y.; Hazu, K.; Ishiguro, T.; Fukuda, T.; Chichibu, S. F.

2012-04-01

A rear-excitation femtosecond-laser-driven photoelectron gun (PE-gun) is developed for measuring time-resolved cathodoluminescence (TRCL) spectrum of wide bandgap materials and structures such as semiconductors and phosphors. The maximum quantum efficiency of a 20-nm-thick Au photocathode excited using a frequency-tripled Al2O3:Ti laser under a rear-excitation configuration is 3.6×10-6, which is a reasonable value for a PE-gun. When the distance between the front edge of the PE-gun and the observation point is 10 mm, the narrowest electron-beam (e-beam) diameter is 19 μm, which corresponds to one tenth of the laser-beam diameter and is comparable to the initial e-beam diameter of a typical W hair-pin filament of thermionic electron-gun. From the results of TRCL measurements on the freestanding GaN grown by the ammonothermal method and a GaN homoepitaxial film grown by metalorganic vapor phase epitaxy, overall response time for the present TRCL system is estimated to be 8 ps. The value is the same as that of time-resolved photoluminescence measurement using the same excitation laser pulses, meaning that the time-resolution is simply limited by the streak-camera, not by the PE-gun performance. The result of numerical simulation on the temporal e-beam broadening caused by the space-charge-effect suggests that the present PE-gun can be used as a pulsed e-beam source for spatio-time-resolved cathodoluminescence, when equipped in a scanning electron microscope.
LX-10 Explosive Damage Studies

DTIC Science & Technology

2015-03-03

samples were fired from a smooth bore, 18-mm gun against a steel target at various velocities. The resulting debris was NAWCWD TM 8757 4 collected...Management Services. The breach of the gun barrel was designed to operate with either powder or gas-driven actuation. The 18-mm barrel was fired using...from a smooth-bore, 18-mm gun against a steel target at various velocities. The resulting debris is collected and fired in a manometric closed vessel
Electrical and Thermal Effects of Rail Cladding in a Full-Scale Launcher

DTIC Science & Technology

1998-04-01

A. E. Zielinski , "Current and Heat Transport in the Cannon-Caliber Electromagnetic Gun Armature," Army Research Laboratory, ARL-MR-258, August...Laboratory AMSRL-CI-LP Technical Library 305 Aberdeen Prvg Grd, MD 21005-5066 Mr. Dave Bauer lAP Research, Incorporated 2763 Culver Avenue Dayton...TX 78759 Mr. Robert J. Taylor Lockheed Martin Vought Systems M/S: WT-21 P.O. Box 650003 Dallas, TX 75265-0003 Mr. Alex Zielinski U.S. Army
Design of a 500 MJ, 5 MA power supply

NASA Astrophysics Data System (ADS)

Pappas, J. A.; Headifen, G. R.; Weldon, J. M.; Wright, J. C.; Zowarka, R. C.; Aanstoos, T. A.; Kajs, J. H.

1993-01-01

The design of a 500 MJ, 5 MA power supply for rail gun experiments under the Battery Upgraded Supply (BUS) program is examined. About 50,000 12-volt lead acid batteries are required to reach this level. BUS will be required to perform up to two discharges per week. Therefore, BUS is designed to be a low-maintenance, reliable, and fault-tolerant power supply. The design of BUS and the details of its subsystems are described.
Switching for electric rail guns

NASA Astrophysics Data System (ADS)

Barber, J. P.; Bauer, D. P.

1984-03-01

The switching requirements of single-stage electric railguns powered by inductive energy stores are analyzed, and the design of a 500-kA commutation switch is shown. The closed, commutation, and off states of the switch and the reclosure function at the end of the projectile acceleration are discussed in general terms, and the specific requirements of the railgun facility at Australian National University are listed. The switch designed is essentially a railgun mounted perpendicular to the breech of the electric railgun, with the armature accelerating down copper rails at closing speeds from 50 m/sec at 100 kA to 300 m/sec at 500 kA to commutate current to the railgun. Commutation time and maximum voltage during 200 shots at 400 kA were found to be 50 microsec and 100 V; commutation inductance was 18-20 nH.
DC-driven plasma gun: self-oscillatory operation mode of atmospheric-pressure helium plasma jet comprised of repetitive streamer breakdowns

NASA Astrophysics Data System (ADS)

Wang, Xingxing; Shashurin, Alexey

2017-02-01

This paper presents and studies helium atmospheric pressure plasma jet comprised of a series of repetitive streamer breakdowns, which is driven by pure DC high voltage (self-oscillatory behavior). The repetition frequency of the breakdowns is governed by the geometry of discharge electrodes/surroundings and gas flow rate. Each next streamer is initiated when the electric field on the anode tip recovers after the previous breakdown and reaches the breakdown threshold value of about 2.5 kV cm-1. One type of the helium plasma gun designed using this operational principle is demonstrated. The gun operates on about 3 kV DC high voltage and is comprised of the series of the repetitive streamer breakdowns at a frequency of about 13 kHz.
Focusing experiments in plasma coaxial railguns

NASA Astrophysics Data System (ADS)

Driga, M. D.; Cook, R. W.; Thelen, R. F.

1986-11-01

Results are reported from experiments on focusing of plasma fired from a coaxial electromagnetic gun (CEMG). The plasma used, obtained by exploding a metallic fuse at the gun breech, comprised metal vapor, metallic liquid droplets and small chunks of solid metal. An azimuthal current, and thereby an axial field, was introduced at the breech of the CEMG by a solenoid. Previous studies indicated that the field would cause vaporized metal to form into a self-stabilizing toroidal plasma. Test shots instrumented with Languir probes and pick-up coils did not reveal the presence of toroidal plasma rings. However, post-mortem of the 30 cm rail showed that only one-third of the 3 mg Al fuse metal remained in the bore. Further, a toroidal hole was punched in a diagnostic screen at the bore exit after one shot.
A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Shuang; Wang, Kaile; Zuo, Shasha

A handheld low temperature atmospheric pressure air plasma gun based on a dielectric barrier structure with hollow electrodes was proposed. The portable plasma gun with an embedded mini air pump was driven by a 12 V direct voltage battery. The air plasma jet generated from the gun could be touched without a common shock hazard. Besides working in air, the plasma gun can also work in water. The diagnostic result of optical emission spectroscopy showed the difference in reactive species of air plasma jet between in air and in water. The plasma gun was excited in 20 ml chloroauric acid aqueous solutionmore » with a concentration of 1.214 mM. A significant amount of gold nanoparticles were synthesized after 2 min continuous discharge. The plasma gun with these unique features is applicable in plasma medicine, etching, and s-nthesis of nanomaterials.« less
A Compact 700-KV Erected Pulse Forming Network for HPM Applications (Postprint)

DTIC Science & Technology

2011-04-28

previously investigated for driving rail guns , electric launchers, or other nonlinear loads albeit for much longer pulse lengths [8]. In this version...The output of the generator was connected to a coaxial CuS04 resistor through 100-ft of coaxial high-voltage cable. The current pulse on the cable was...shown in Figure 6. This pulse was delivered to a 50-ohm cable and measured by a coaxial inline CVR at the generator output. Typical pulse
Human Terrain: A Tactical Issue or a Strategic C4I Problem?

DTIC Science & Technology

2008-05-20

C4I" 20-21 May 2008, George Mason University, Fairfax, Virginia Campus, The original document contains color images . 14. ABSTRACT 15. SUBJECT TERMS...can modify and control it – Terrain is many things: typography ; geology and soil type; it’s natural coverage (forests); it’s roadways, rail lines... image of “gun toting” field researchers who are doing military stuff and not research and in the process are poisoning the environment for real field
A Projectile for a Rectangular Barreled Rail Gun

DTIC Science & Technology

1999-12-01

fins Cfb ’ skin friction drag coefficient for nose/body combination modified for equations of motion Cff’ skin friction drag coefficient for fins...occasionally referred to as the last point method, uses a loop , shown in simplified form in Figure (2) as a flow chart. The program loop takes the final... Cfb ’ = CfofCf(Sno/s+Sbs)/ScsS (4.11) Cff = CfffcfSw/Scss (4.12) 2. Form Drag The form drag coefficients are determined by the methods from
Asymmetric material impact: Achieving free surfaces velocities nearly double that of the projectile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aslam, Tariq; Dattelbaum, Dana; Gustavsen, Richard

Hypervelocity impact speeds are often limited by practical considerations in guns and explosive driven systems. In particular, for gas guns (both powder driven and light gas guns), there is the general trend that higher projectile speeds often come at the expense of smaller diameters, and thus less time for examining shock phenomena prior to two dimensional release waves affecting the observed quantities of interest. Similarly, explosive driven systems have their own set of limiting conditions due to limitations in explosive energy and size of devices required as engineering dimensions increase. The focus in this study is to present a methodologymore » of obtaining free surface velocities well in excess of the projectile velocity. The key to this approach is in using a high impedance projectile that impacts a series of progressively lower impedance materials. The free surface velocity (if they were separated) of each of the progressively lower impedance materials would increase for each material. The theory behind this approach, as well as experimental results are presented.« less
Asymmetric material impact: Achieving free surfaces velocities nearly double that of the projectile

DOE PAGES

Aslam, Tariq; Dattelbaum, Dana; Gustavsen, Richard; ...

2015-05-19

Hypervelocity impact speeds are often limited by practical considerations in guns and explosive driven systems. In particular, for gas guns (both powder driven and light gas guns), there is the general trend that higher projectile speeds often come at the expense of smaller diameters, and thus less time for examining shock phenomena prior to two dimensional release waves affecting the observed quantities of interest. Similarly, explosive driven systems have their own set of limiting conditions due to limitations in explosive energy and size of devices required as engineering dimensions increase. The focus in this study is to present a methodologymore » of obtaining free surface velocities well in excess of the projectile velocity. The key to this approach is in using a high impedance projectile that impacts a series of progressively lower impedance materials. The free surface velocity (if they were separated) of each of the progressively lower impedance materials would increase for each material. The theory behind this approach, as well as experimental results are presented.« less

Rail accelerators for space transportation: An experimental investigation

NASA Technical Reports Server (NTRS)

Zana, L. M.; Kerslake, W. R.; Sturman, J. L.

1986-01-01

An experimental program was conducted at the Lewis Research Center with the objective of investigating the technical feasibility of rail accelerators for propulsion applications. Single-stage, plasma driven rail accelerators of small (4 by 6 mm) and medium (12.5 by 12.5 mm) bores were tested at peak accelerating currents of 50 to 450 kA. Streak-camera photography was used to provide a qualitative description of plasma armature acceleration. The effects of plasma blowby and varying bore pressure on the behavior of plasma armatures were studied.
Engineering design of the PLX- α coaxial gun

NASA Astrophysics Data System (ADS)

Cruz, Edward; Brockington, Samuel; Case, Andrew; Luna, Marco; Witherspoon, Douglas; Langendorf, Samuel

2016-10-01

We describe the engineering and technical aspects of the coaxial gun designed for the 60-gun scaling study of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion. Each coaxial gun incorporates a fast, dense gas injection and triggering system, a compact low-weight pfn with integral sparkgap switching, and a contoured gap designed to suppress the blow-by instability. Alpha1 and Alpha2 guns are compared, with emphasis on the improvements on Alpha2, which include a faster more robust gas valve, an improved electrode contour, a custom 600- μF, 5-kV pfn, and a set of six inline sparkgap switches operated in parallel. The switch and pfn configurations are mounted directly to the back of the gun, and are designed to reduce inductance, cost, and complexity, maximize efficiency and system reliability, and ensure symmetric current flow. We will provide a detailed overview of the design choices made for the PLX- α coaxial gun. This work supported by the ARPA-E ALPHA Program.
A 16 MJ compact pulsed power system for electromagnetic launch

NASA Astrophysics Data System (ADS)

Dai, Ling; Zhang, Qin; Zhong, Heqing; Lin, Fuchang; Li, Hua; Wang, Yan; Su, Cheng; Huang, Qinghua; Chen, Xu

2015-07-01

This paper has established a compact pulsed power system (PPS) of 16 MJ for electromagnetic rail gun. The PPS consists of pulsed forming network (PFN), chargers, monitoring system, and current junction. The PFN is composed of 156 pulse forming units (PFUs). Every PFU can be triggered simultaneously or sequentially in order to obtain different total current waveforms. The whole device except general control table is divided into two frameworks with size of 7.5 m × 2.2 m × 2.3 m. It is important to estimate the discharge current of PFU accurately for the design of the whole electromagnetic launch system. In this paper, the on-state characteristics of pulse thyristor have been researched to improve the estimation accuracy. The on-state characteristics of pulse thyristor are expressed as a logarithmic function based on experimental data. The circuit current waveform of the single PFU agrees with the simulating one. On the other hand, the coaxial discharge cable is a quick wear part in PFU because the discharge current will be up to dozens of kA even hundreds of kA. In this article, the electromagnetic field existing in the coaxial cable is calculated by finite element method. On basis of the calculation results, the structure of cable is optimized in order to improve the limit current value of the cable. At the end of the paper, the experiment current wave of the PPS with the load of rail gun is provided.
A 16 MJ compact pulsed power system for electromagnetic launch.

PubMed

Dai, Ling; Zhang, Qin; Zhong, Heqing; Lin, Fuchang; Li, Hua; Wang, Yan; Su, Cheng; Huang, Qinghua; Chen, Xu

2015-07-01

This paper has established a compact pulsed power system (PPS) of 16 MJ for electromagnetic rail gun. The PPS consists of pulsed forming network (PFN), chargers, monitoring system, and current junction. The PFN is composed of 156 pulse forming units (PFUs). Every PFU can be triggered simultaneously or sequentially in order to obtain different total current waveforms. The whole device except general control table is divided into two frameworks with size of 7.5 m × 2.2 m × 2.3 m. It is important to estimate the discharge current of PFU accurately for the design of the whole electromagnetic launch system. In this paper, the on-state characteristics of pulse thyristor have been researched to improve the estimation accuracy. The on-state characteristics of pulse thyristor are expressed as a logarithmic function based on experimental data. The circuit current waveform of the single PFU agrees with the simulating one. On the other hand, the coaxial discharge cable is a quick wear part in PFU because the discharge current will be up to dozens of kA even hundreds of kA. In this article, the electromagnetic field existing in the coaxial cable is calculated by finite element method. On basis of the calculation results, the structure of cable is optimized in order to improve the limit current value of the cable. At the end of the paper, the experiment current wave of the PPS with the load of rail gun is provided.
Traffic Flow of Interacting Self-Driven Particles: Rails and Trails, Vehicles and Vesicles

NASA Astrophysics Data System (ADS)

Chowdhury, Debashish

One common feature of a vehicle, an ant and a kinesin motor is that they all convert chemical energy, derived from fuel or food, into mechanical energy required for their forward movement; such objects have been modelled in recent years as self-driven particles. Cytoskeletal filaments, e.g., microtubules, form a rail network for intra-cellular transport of vesicular cargo by molecular motors like, for example, kinesins. Similarly, ants move along trails while vehicles move along lanes. Therefore, the traffic of vehicles and organisms as well as that of molecular motors can be modelled as systems of interacting self-driven particles; these are of current interest in non-equilibrium statistical mechanics. In this paper we point out the common features of these model systems and emphasize the crucial differences in their physical properties.
A Study of Slipper and Rail Wear Interaction at Low Speed

DTIC Science & Technology

2014-06-19

on gun barrel steel 24 Figure 2.5: Plot of Montgomery Pin on Disk Data with Curve Fit[11] for different pressure-velocity values. The function for this...Normal Force (N) F̃ Normalized Pressure (N/ m2 /N/ m2 ) lc Length of Contact Area (mm) r Radius of Asperity (µm) s Mie-Grüneisen Material Parameter T...revolution of the early 1900s drove the field of Tribology as many machines with a myriad of moving parts containing surfaces that wore against each other
Pulse power applications of silicon diodes in EML capacitive pulsers

NASA Astrophysics Data System (ADS)

Dethlefsen, Rolf; McNab, Ian; Dobbie, Clyde; Bernhardt, Tom; Puterbaugh, Robert; Levine, Frank; Coradeschi, Tom; Rinaldi, Vito

1993-01-01

Crowbar diodes are used for increasing the energy transfer from capacitive pulse forming networks. They also prevent voltage reversal on the energy storage capacitors. 52 mm diameter diodes with a 5 kV reverse blocking voltage, rated 40 kA were successfully used for the 32 MJ SSG rail gun. An uprated diode with increased current capability and a 15 kV reverse blocking voltage has been developed. Transient thermal analysis has predicted the current ratings for different pulse length. Analysis verification is obtained from destructive testing.
Contoured-gap coaxial guns for imploding plasma liner experiments

NASA Astrophysics Data System (ADS)

Witherspoon, F. D.; Case, A.; Brockington, S.; Cassibry, J. T.; Hsu, S. C.

2014-10-01

Arrays of supersonic, high momentum flux plasma jets can be used as standoff compression drivers for generating spherically imploding plasma liners for driving magneto-inertial fusion, hence the name plasma-jet-driven MIF (PJMIF). HyperV developed linear plasma jets for the Plasma Liner Experiment (PLX) at LANL where two guns were successfully tested. Further development at HyperV resulted in achieving the PLX goal of 8000 μg at 50 km/s. Prior work on contoured-gap coaxial guns demonstrated an approach to control the blowby instability and achieved substantial performance improvements. For future plasma liner experiments we propose to use contoured-gap coaxial guns with small Minirailgun injectors. We will describe such a gun for a 60-gun plasma liner experiment. Discussion topics will include impurity control, plasma jet symmetry and topology (esp. related to uniformity and compactness), velocity capability, and techniques planned for achieving gun efficiency of >50% using tailored impedance matched pulse forming networks. Mach2 and UAH SPH code simulations will be included. Work supported by US DOE DE-FG02-05ER54810.
Non-solenoidal startup and low-β operations in Pegasus

NASA Astrophysics Data System (ADS)

Schlossberg, D. J.; Battaglia, D. J.; Bongard, M. W.; Fonck, R. J.; Redd, A. J.

2009-11-01

Non-solenoidal startup using point-source DC helicity injectors (plasma guns) has been achieved in the Pegasus Toroidal Experiment for plasmas with Ip in excess of 100 kA using Iinj<4,A. The maximum achieved Ip tentatively scales as √ITFIinj/w, where w is the radial thickness of the gun-driven edge. The Ip limits appear to conform to a simple stationary model involving helicity conservation and Taylor relaxation. However, observed MHD activity reveals the additional dynamics of the relaxation process, evidenced by intermittent bursts of n=1 activity correlated with rapid redistribution of the current channel. Recent upgrades to the gun system provide higher helicity injection rates, smaller w, a more constrained gun current path, and more precise diagnostics. Experimental goals include extending parametric scaling studies, determining the conditions where parallel conduction losses dominate the helicity dissipation, and building the physics understanding of helicity injection to confidently design gun systems for larger, future tokamaks.
High Current Systems for HyperV and PLX Plasma Railguns

NASA Astrophysics Data System (ADS)

Brockington, S.; Case, A.; Messer, S.; Elton, R.; Witherspoon, F. D.

2011-10-01

HyperV is developing gas fed, pulsed, plasma railgun accelerators for PLX and other high momentum plasma applications. The present 2.5 cm square-bore plasma railgun forms plasma armatures from high density neutral gas (argon), preionizes it electrothermally, and accelerates the armature with 30 cm long parallel-plate railgun electrodes driven by a pulse forming network (PFN). Recent experiments have successfully formed and accelerated plasma armatures of ~4 mg at 40 km/s, with PFN currents of ~400 kA. In order to further increase railgun performance to the PLX design goal of 8 mg at 50 km/s, the PFN was upgraded to support currents of up to ~750 kA. A high voltage, high current linear array spark-gap switch and flexible, low-inductance transmission line were designed and constructed to handle the increased current load. We will describe these systems and present initial performance data from high current operation of the plasma rail gun from spectroscopy, interferometry, and imaging systems as well as pressure, magnetic field, and optical diagnostics. High current performance of railgun bore materials for electrodes and insulators will also be discussed as well as plans for upcoming experimentation with advanced materials. Supported by the U.S. DOE Joint Program in HEDLP.
Numerical prediction of rail roughness growth on tangent railway tracks

NASA Astrophysics Data System (ADS)

Nielsen, J. C. O.

2003-10-01

Growth of railhead roughness (irregularities, waviness) is predicted through numerical simulation of dynamic train-track interaction on tangent track. The hypothesis is that wear is caused by longitudinal slip due to driven wheelsets, and that wear is proportional to the longitudinal frictional power in the contact patch. Emanating from an initial roughness spectrum corresponding to a new or a recent ground rail, an initial roughness profile is determined. Wheel-rail contact forces, creepages and wear for one wheelset passage are calculated in relation to location along a discretely supported track model. The calculated wear is scaled by a chosen number of wheelset passages, and is then added to the initial roughness profile. Field observations of rail corrugation on a Dutch track are used to validate the simulation model. Results from the simulations predict a large roughness growth rate for wavelengths around 30-40 mm. The large growth in this wavelength interval is explained by a low track receptance near the sleepers around the pinned-pinned resonance frequency, in combination with a large number of driven passenger wheelset passages at uniform speed. The agreement between simulations and field measurements is good with respect to dominating roughness wavelength and annual wear rate. Remedies for reducing roughness growth are discussed.
Preliminary analysis of space mission applications for electromagnetic launchers

NASA Technical Reports Server (NTRS)

Miller, L. A.; Rice, E. E.; Earhart, R. W.; Conlon, R. J.

1984-01-01

The technical and economic feasibility of using electromagnetically launched EML payloads propelled from the Earth's surface to LEO, GEO, lunar orbit, or to interplanetary space was assessed. Analyses of the designs of rail accelerators and coaxial magnetic accelerators show that each is capable of launching to space payloads of 800 KG or more. A hybrid launcher in which EML is used for the first 2 KM/sec followed by chemical rocket stages was also tested. A cost estimates study shows that one to two EML launches per day are needed to break even, compared to a four-stage rocket. Development models are discussed for: (1) Earth orbital missions; (2) lunar base supply mission; (3) solar system escape mission; (4) Earth escape missions; (5) suborbital missions; (6) electromagnetic boost missions; and (7) space-based missions. Safety factors, environmental impacts, and EML systems analysis are discussed. Alternate systems examined include electrothermal thrustors, an EML rocket gun; an EML theta gun, and Soviet electromagnetic accelerators.
The PLX- α Plasma Guns: Progress and Plans

NASA Astrophysics Data System (ADS)

Witherspoon, F. D.; Brockington, S.; Case, A.; Cruz, E.; Luna, M.; Thio, Y. C. Francis; LANL PLX-α Team

2017-10-01

The ALPHA coaxial plasma guns are being developed to support a 60-gun scaling study of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion (PJMIF). Seven complete guns have been delivered to LANL with 6 guns currently undergoing simultaneous test firings on PLX. The guns are designed to operate over a range of parameters: 0.5-5.0 mg of Ar, Ne, N2, Kr, and Xe; 20-60 km/s; 2 × 1016 cm-3 muzzle density; and up to 7.5 kJ stored energy per gun. Each coaxial gun incorporates a fast dense gas injection and triggering system, a compact low-weight pfn with integral sparkgap switching, and a contoured coaxial gap to suppress the blow-by instability. Optimizing parameter scans performed at HyperV have achieved : 4 mg at >50 km/s and length of 10 cm. Peak axial density 30 cm from the muzzle is 2 ×1016 cm-3. We will provide an overview of the experimental results, along with plans for further improvements in reliability, maintainability, fabricability, and plasma jet performance, with the latter focused on further improvements in the fast gas valve and the ignitors. This work supported by the ARPA-E ALPHA Program under contract DE-AR0000566 and Strong Atomics, LLC.
Coaxial-gun design and testing for the PLX- α Project

NASA Astrophysics Data System (ADS)

Witherspoon, F. Douglas; Brockington, Samuel; Case, Andrew; Cruz, Edward; Luna, Marco; Langendorf, Samuel

2016-10-01

We describe the Alpha coaxial gun designed for a 60-gun scaling study of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion (PJMIF). The guns operate over a range of parameters: 0.5-5.0 mg of Ar, Ne, N2, Kr, and Xe; 20-60 km/s; 2 × 1016 cm-3 muzzle density; and up to 7.5 kJ stored energy per gun. Each coaxial gun incorporates a fast dense gas injection and triggering system, a compact low-weight pfn with integral sparkgap switching, and a contoured gap designed to suppress the blow-by instability. The latest design iteration incorporates a faster more robust gas valve, an improved electrode contour, a custom 600- μF, 5-kV pfn, and six inline sparkgap switches operated in parallel. The switch and pfn are mounted directly to the back of the gun and are designed to reduce inductance, cost, and complexity, maximize efficiency and system reliability, and ensure symmetric current flow. We provide a brief overview of the design choices, the projected performance over the parameter ranges mentioned above, and experimental results from testing of the PLX- α coaxial gun. This work supported by the ARPA-E ALPHA Program.
Engineering design of the PLX- α coaxial gun

NASA Astrophysics Data System (ADS)

Cruz, E.; Brockington, S.; Case, A.; Luna, M.; Witherspoon, F. D.; Thio, Y. C. Francis; PLX-α Team

2017-10-01

We describe the engineering and technical improvements, as well as provide a detailed overview of the design choices, of the latest PLX- α coaxial gun designed for the 60-gun scaling study of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion. Each coaxial gun incorporates a fast, dense gas injection and triggering system, a compact low-weight pfn with integral sparkgap switching, and a contoured gap designed to suppress the blow-by instability. The evolution of the latest Alpha gun is presented with emphasis on its upgraded performance. Changes include a faster more robust gas valve, better-quality ceramic insulator material and enhancements to overall design layout. These changes result in a gun with increased repeatability, reduced potential failure modes, improved fault tolerance and better than expected efficiency. A custom 600- μF, 5-kV pfn and a set of six inline sparkgap switches operated in parallel are mounted directly to the back of the gun, and are designed to reduce inductance, cost, and complexity, maximize efficiency and system reliability, and ensure symmetric current flow. This work supported by the ARPA-E ALPHA Program under contract DE-AR0000566 and Strong Atomics, LLC.
Drive control and position measurement of RailCab vehicles driven by linear motors

NASA Astrophysics Data System (ADS)

Pottharst, Andreas; Henke, Christian; Schneider, Tobias; Böcker, Joachim; Grotstollen, Horst

2006-11-01

The novel railway system RailCab makes use of autonomous vehicles which are driven by an AC linear motor. Depending on the track-side motor part, long-stator or short-stator operations are possible. The paper deals with the operation of the doubly-fed induction motor which is used for motion control and for transferring the energy required onboard the vehicle. This type of linear motor synchronization of the traveling fields generated by the stationary primary and moving secondary windings is an important and demanding task because the instantaneous positions of the vehicle or the primary traveling wave must be determined with high accuracy. The paper shows how this task is solved at the moment and what improvements are under development.
An advanced EM railgun design

NASA Astrophysics Data System (ADS)

Hallse, R. L.; Weiman, S. M.

1986-11-01

A progress report is presented from a study of structural design concepts for a large, square-bore, multi-shot railgun. The railgun is to have multi-MA current, a barrel longer than 15 ft, a thermally-managed breech 3 ft long, and pre-stressed internal components. The design, as of early 1986, had a one-piece monolithic circular shell, S-glass/epoxy insulators, and bolt-loaded steel pre-stressed plates. Thermal management is achieved with longitudinal cooling slots with numerous water and air inlets. The device is instrumented for gun current, voltage, bore velocity, magnetic field, rail and armature current, bore dimensions and coolant temperature.
The Battle of Jutland

DTIC Science & Technology

1984-04-01

battle- cruiser LJLQQ,, was "booed" and "jeered at" by dockyard workmen as she slipped into her berth after the battle ( 12 :250). Why such a negative...of May in 1916. Until the Battle of Jutland, the Royal Navy had not been seriously challenged since 1805 when Admirals Nelson and...Unique because of its design as an "all big-gun ship," she carried ten 12 -inch guns, was turbine driven, and
Mental Illness and Firearms: Legal Context and Clinical Approaches.

PubMed

Pinals, Debra A; Anacker, Lisa

2016-12-01

Gun violence and mental illness is a major area of media attention, especially because highly publicized mass shootings seem to have become more commonly reported in the press. Gun access also is undergoing a highly politicized debate in the United States. It is important for mental health practitioners to understand the background and context of laws related to firearms access, and to understand data related to risk of suicide and violence toward others caused by gun violence among persons with mental illness. In addition, clinically driven risk assessments with specific inquiry related to firearms can be important for identifying individuals for whom firearm-focused clinical risk mitigation may be warranted. Copyright © 2016 Elsevier Inc. All rights reserved.
The status of normal conducting RF (NCRF) guns, a summary of the ERL2005 workshop

NASA Astrophysics Data System (ADS)

Dowell, David H.; Lewellen, John W.; Nguyen, Dinh; Rimmer, Robert

2006-02-01

The 32nd Advanced ICFA Beam Dynamics Workshop on Energy Recovering Linacs (ERL2005) was held at Jefferson Laboratory, March 20-23, 2005. A wide range of ERL-related topics were presented and discussed in several working groups with Working Group 1 concentrating upon the physics and technology issues for DC, superconducting RF (SRF) and normal conducting RF (NCRF) guns. This paper summarizes the NCRF gun talks and reviews the status of NCRF gun technology. It begins with the presentations made on the subject of low-frequency, high-duty factor guns most appropriate for ERLs. One such gun at 433 MHz was demonstrated at 25%DF in 1992, while the CW and much improved version is currently being constructed at 700 MHz for LANL. In addition, the idea of combining the NCRF gun with a SRF linac booster was presented and is described in this paper. There was also a talk on high-field guns typically used for SASE-free electron lasers. In particular, the DESY coaxial RF feed design provides rotationally symmetric RF fields and greater flexibility in the placement of the focusing magnetic field. While in the LCLS approach, the symmetric fields are obtained with a dual RF feed and racetrack cell shape. Although these guns cannot be operated at high-duty factor, they do produce the best quality beams. With these limitations in mind, a section with material not presented at the workshop has been included in the paper. This work describes a re-entrant approach which may allow NCRF guns to operate with simultaneously increased RF fields and duty factors. And finally, a novel proposal describing a high-duty factor, two-frequency RF gun using a field emission source instead of a laser driven photocathode was also presented.

Flux amplification and sustainment of ST plasmas by multi-pulsed coaxial helicity injection on HIST

NASA Astrophysics Data System (ADS)

Higashi, T.; Ishihara, M.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2010-11-01

The Helicity Injected Spherical Torus (HIST) device has been developed towards high-current start up and sustainment by Multi-pulsed Coaxial Helicity Injection (M-CHI) method. Multiple pulses operation of the coaxial plasma gun can build the magnetic field of STs and spheromak plasmas in a stepwise manner. So far, successive gun pulses on SSPX at LLNL were demonstrated to maintain the magnetic field of spheromak in a quasi-steady state against resistive decay [1]. The resistive 3D-MHD numerical simulation [2] for STs reproduced the current amplification by the M-CHI method and confirmed that stochastic magnetic field was reduced during the decay phase. By double pulsed operation on HIST, the plasma current was effectively amplified against the resistive decay. The life time increases up to 10 ms which is longer than that in the single CHI case (4 ms). The edge poloidal fields last between 0.5 ms and 6 ms like a repetitive manner. During the second driven phase, the toroidal ion flow is driven in the same direction as the plasma current as well as in the initial driven phase. At the meeting, we will discuss a current amplification mechanism based on the merging process with the plasmoid injected secondly from the gun. [1] B. Hudson et al., Phys. Plasmas Vol.15, 056112 (2008). [2] Y. Kagei et al., J. Plasma Fusion Res. Vol.79, 217 (2003).
Inertial fusion energy target injection, tracking, and beam pointing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petzoldt, Ronald Wayne

1995-03-07

Several cryogenic targets must be injected each second into a reaction chamber. Required target speed is about 100 m/s. Required accuracy of the driver beams on target is a few hundred micrometers. Fuel strength is calculated to allow acceleration in excess of 10,000 m/s 2 if the fuel temperature is less than 17 K. A 0.1 μm thick dual membrane will allow nearly 2,000 m/s 2 acceleration. Acceleration is gradually increased and decreased over a few membrane oscillation periods (a few ms), to avoid added stress from vibrations which could otherwise cause a factor of two decrease in allowed acceleration.more » Movable shielding allows multiple targets to be in flight toward the reaction chamber at once while minimizing neutron heating of subsequent targets. The use of multiple injectors is recommended for redundancy which increases availability and allows a higher pulse rate. Gas gun, rail gun, induction accelerator, and electrostatic accelerator target injection devices are studied, and compared. A gas gun is the preferred device for indirect-drive targets due to its simplicity and proven reliability. With the gas gun, the amount of gas required for each target (about 10 to 100 mg) is acceptable. A revolver loading mechanism is recommended with a cam operated poppet valve to control the gas flow. Cutting vents near the muzzle of the gas gun barrel is recommended to improve accuracy and aid gas pumping. If a railgun is used, we recommend an externally applied magnetic field to reduce required current by an order of magnitude. Optical target tracking is recommended. Up/down counters are suggested to predict target arrival time. Target steering is shown to be feasible and would avoid the need to actively point the beams. Calculations show that induced tumble from electrostatically steering the target is not excessive.« less
Application of Template Matching for Improving Classification of Urban Railroad Point Clouds

PubMed Central

Arastounia, Mostafa; Oude Elberink, Sander

2016-01-01

This study develops an integrated data-driven and model-driven approach (template matching) that clusters the urban railroad point clouds into three classes of rail track, contact cable, and catenary cable. The employed dataset covers 630 m of the Dutch urban railroad corridors in which there are four rail tracks, two contact cables, and two catenary cables. The dataset includes only geometrical information (three dimensional (3D) coordinates of the points) with no intensity data and no RGB data. The obtained results indicate that all objects of interest are successfully classified at the object level with no false positives and no false negatives. The results also show that an average 97.3% precision and an average 97.7% accuracy at the point cloud level are achieved. The high precision and high accuracy of the rail track classification (both greater than 96%) at the point cloud level stems from the great impact of the employed template matching method on excluding the false positives. The cables also achieve quite high average precision (96.8%) and accuracy (98.4%) due to their high sampling and isolated position in the railroad corridor. PMID:27973452
Broadening the Perspective on Gun Violence: An Examination of the Firearms Industry, 1990-2015.

PubMed

Smith, Victoria M; Siegel, Michael; Xuan, Ziming; Ross, Craig S; Galea, Sandro; Kalesan, Bindu; Fleegler, Eric; Goss, Kristin A

2017-11-01

Firearm violence injures or kills 100,000 Americans each year. This paper applies the Host-Agent-Vector-Environment model to this issue. Research on firearm violence tends to focus on two elements-the host (i.e., victims of firearm violence) and the environment (i.e., gun policies)-but little attention has been paid to the agent (the gun and ammunition) or the vector (firearm manufacturers, dealers, and the industry lobby). Using Bureau of Alcohol, Tobacco, Firearms and Explosives data, trends in firearm manufacturing were investigated from 1990 to 2015. Outcome measures included: (1) trends in domestic gun manufacturing by weapon type; (2) trends in production by firearm caliber; and (3) 2015 market share by type of firearm and company. Data were collected and analyzed in 2016. Overall domestic firearms production decreased slightly from 1996 through 2004, and then steadily increased from 1.7% in 2005 to 13.8% in 2013, when >10 million firearms were produced for the domestic market. The increase in total firearm production was driven by the increased production of pistols and rifles. Within the pistol category, increased production was attributable to an increase in higher caliber weapons. Similar trends were observed in gun purchases and recovered and traced crime guns. Trends in firearm manufacturing reveal a shift toward more-lethal weapons, and this trend is also observed in gun purchases and crime gun traces. This may reflect a societal shift in cultural practices and norms related to guns and could inform strategies to reduce firearm violence. Copyright © 2017 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.
The Status of Normal Conducting RF (NCRF) Guns, a Summary of the ERL2005 Workshop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dowell, D.H.; /SLAC; Lewellen, J.W.

The 32nd Advanced ICFA Beam Dynamics Workshop on Energy Recovering Linacs (ERL2005) was held at Jefferson Laboratory, March 20 to 23, 2005. A wide range of ERL-related topics were presented and discussed in several working groups with Working Group 1 concentrated upon the physics and technology issues for DC, superconducting RF (SRF) and normal conducting RF (NCRF) guns. This paper summarizes the NCRF gun talks and reviews the status of NCRF gun technology. It begins with the presentations made on the subject of low-frequency, high-duty factor guns most appropriate for ERLs. One such gun at 433MHz was demonstrated at 25%DFmore » in 1992, while the CW and much improved version is currently being constructed at 700MHz for LANL. In addition, the idea of combining the NCRF gun with a SRF linac booster was presented and is described in this paper. There was also a talk on high-field guns typically used for SASE free electron lasers. In particular, the DESY coaxial RF feed design provides rotationally symmetric RF fields and greater flexibility in the placement of the focusing magnetic field. While in the LCLS approach, the symmetric fields are obtained with a dual RF feed and racetrack cell shape. Although these guns cannot be operated at high-duty factor, they do produce the best quality beams. With these limitations in mind, a section with material not presented at the workshop has been included in the paper. This work describes a re-entrant approach which may allow NCRF guns to operate with simultaneously increased RF fields and duty factors. And finally, a novel proposal describing a high-duty factor, two-frequency RF gun using a field emission source instead of a laser driven photocathode was also presented.« less
The status of normal conducting RF (NCRF) guns; a summary of the ERL2005 Workshop

DOE Office of Scientific and Technical Information (OSTI.GOV)

D.H. Dowell; J.W. Lewellen; D. Nguyen

The 32nd Advanced ICFA Beam Dynamics Workshop on Energy Recovering Linacs (ERL2005) was held at Jefferson Laboratory, March 20 to 23, 2005. A wide range of ERL-related topics were presented and discussed in several working groups with Working Group 1 concentrated upon the physics and technology issues for DC, superconducting RF (SRF) and normal conducting RF (NCRF) guns. This paper summarizes the NCRF gun talks and reviews the status of NCRF gun technology. It begins with the presentations made on the subject of low-frequency, high-duty factor guns most appropriate for ERLs. One such gun at 433MHz was demonstrated at 25%DFmore » in 1992, while the CW and much improved version is currently being constructed at 700MHz for LANL. In addition, the idea of combining the NCRF gun with a SRF linac booster was presented and is described in this paper. There was also a talk on high-field guns typically used for SASE free electron lasers. In particular, the DESY coaxial RF feed design provides rotationally symmetric RF fields and greater flexibility in the placement of the focusing magnetic field. While in the LCLS approach, the symmetric fields are obtained with a dual RF feed and racetrack cell shape. Although these guns cannot be operated at high-duty factor, they do produce the best quality beams. With these limitations in mind, a section with material not presented at the workshop has been included in the paper. This work describes a re-entrant approach which may allow NCRF guns to operate with simultaneously increased RF fields and duty factors. And finally, a novel proposal describing a high-duty factor, two-frequency RF gun using a field emission source instead of a laser driven photocathode was also presented.« less
Cerenkov Radiator Driven by a Superconducting RF Electron Gun

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poole, B R; Harris, J R

2011-03-07

The Naval Postgraduate School (NPS), Niowave, Inc., and Boeing have recently demonstrated operation of the first superconducting RF electron gun based on a quarter wave resonator structure. In preliminary tests, this gun has produced 10 ps long bunches with charge in excess of 78 pC, and with beam energy up to 396 keV. Initial testing occurred at Niowave's Lansing, MI facility, but the gun and diagnostic beam line are planned for installation in California in the near future. The design of the diagnostic beam line is conducive to the addition of a Cerenkov radiator without interfering with other beam linemore » operations. Design and simulations of a Cerenkov radiator, consisting of a dielectric lined waveguide will be presented. The dispersion relation for the structure is determined and the beam interaction is studied using numerical simulations. The characteristics of the microwave radiation produced in both the short and long bunch regimes will be presented.« less
An overview of beam diagnostic and control systems for 50 MeV AREAL Linac

NASA Astrophysics Data System (ADS)

Sargsyan, A. A.; Amatuni, G. A.; Sahakyan, V. V.; Zanyan, G. S.; Martirosyan, N. W.; Vardanyan, V. V.; Grigoryan, B. A.

2017-03-01

Advanced Research Electron Accelerator Laboratory (AREAL) is an electron linear accelerator project with a laser driven RF gun being constructed at CANDLE Synchrotron Research Institute. After the successful operation of the gun section at 5 MeV, a program of facility energy enhancement up to 50 MeV is launched. In this paper the current status of existing diagnostic and control systems, as well as the results of electron beam parameter measurements are presented. The approaches of intended diagnostic and control systems for the upgrade program are also described.
Experimental study of shock-driven cavity collapse with a single-stage gas gun driver

NASA Astrophysics Data System (ADS)

Anderson, Phillip; Betney, Matthew; Doyle, Hugo; Hawker, Nicholas; Roy, Ronald

2014-10-01

This paper explores experimental studies of shock-driven cavity collapse using a single-stage gas gun. Shocks of up to 1 GPa are generated in a hydrogel with the impact of a planar-faced projectile (50 mm dia.). Within the hydrogel, a pre-formed cavity (5 mm dia.) is cast, which is collapsed by the interaction with the shockwave. The basic collapse process involves the formation of a high-speed transverse jet and then a second collapse phase driven from jet impact. Single-shot multi-frame schlieren imaging is used to show the position and timing of optical emission in relation to the collapse hydrodynamics. Further, temporally and spectrally-resolved measurements of the optical emission are made through simultaneous use of multiple band-passed PMTs and an integrating spectrometer. This reveals three distinct pulses of emission possessing different frequency content. The first corresponds to the trapping of gas during jet impact; the second and third correspond to the further inertial collapse of the now toroidal cavity. Plasma models are used to provide the first indication of the temperature of these inertially confined plasmas.
Future space transport

NASA Technical Reports Server (NTRS)

Grishin, S. D.; Chekalin, S. V.

1984-01-01

Prospects for the mastery of space and the basic problems which must be solved in developing systems for both manned and cargo spacecraft are examined. The achievements and flaws of rocket boosters are discussed as well as the use of reusable spacecraft. The need for orbiting satellite solar power plants and related astrionics for active control of large space structures for space stations and colonies in an age of space industrialization is demonstrated. Various forms of spacecraft propulsion are described including liquid propellant rocket engines, nuclear reactors, thermonuclear rocket engines, electrorocket engines, electromagnetic engines, magnetic gas dynamic generators, electromagnetic mass accelerators (rail guns), laser rocket engines, pulse nuclear rocket engines, ramjet thermonuclear rocket engines, and photon rockets. The possibilities of interstellar flight are assessed.
In-state and interstate associations between gun shows and firearm deaths and injuries: A quasi-experimental study

PubMed Central

Matthay, Ellicott C.; Galin, Jessica; Rudolph, Kara E.; Farkas, Kriszta; Wintemute, Garen; Ahern, Jennifer

2018-01-01

Background Gun shows are an important source of firearms, but no adequately powered studies have examined whether these events are associated with increases in firearm injuries. Objective To determine whether gun shows are associated with short-term increases in locally occurring firearm injuries and whether this association differs by the state in which the gun show occurs. Design Quasi-experimental. Setting California. Study Population Individuals in California within driving distance of gun shows. Measurements Gun shows in California and Nevada between 2005 and 2013 (n = 915 shows) and rates of firearm-related deaths, emergency department visits, and inpatient hospitalizations in California. Results Compared to the two weeks before gun shows occurred, post-show firearm injury rates remained stable in regions near California gun shows but increased from 0.67 (95% CI, 0.55 to 0.80) to 1.14 (95% CI, 0.97 to 1.30) per 100,000 in regions near Nevada shows. After adjustment for seasonality and clustering, California shows were not associated with increases in local firearm injuries (RR, 0.99 [95% CI, 0.97 to 1.02]), but Nevada shows were associated with increases in injuries occurring in California (RR, 1.69 [95% CI, 1.16 to 2.45]). The pre-post difference was significantly higher for Nevada shows compared to California shows (Ratio of RRs, 1.70 [95% CI, 1.17 to 2.47]). The Nevada association was driven by significant increases in interpersonal violence firearm injuries (RR, 2.23 [95% CI, 1.01 to 4.89), but corresponded to a small increase in absolute numbers. Non-firearm injuries served as a negative control and were not associated with California or Nevada gun shows. Results were robust to sensitivity analyses. Limitation We only examined firearm injuries in California, and gun show occurrence was not randomized. Conclusion Gun shows occurring in Nevada, but not California, are associated with local, short-term increases in firearm injuries in California. Differing associations for California versus Nevada gun shows may be due to California’s stricter firearms regulations. PMID:29059689
Remote liquid target loading system for LANL two-stage gas gun

NASA Astrophysics Data System (ADS)

Gibson, L. L.; Bartram, B.; Dattelbaum, D. M.; Sheffield, S. A.; Stahl, D. B.

2009-06-01

A Remote Liquid Loading System (RLLS) was designed to load high hazard liquid materials into targets for gas-gun driven impact experiments. These high hazard liquids tend to react with confining materials in a short period of time, degrading target assemblies and potentially building up pressure through the evolution of gas in the reactions. Therefore, the ability to load a gas gun target in place immediately prior to firing the gun, provides the most stable and reliable target fielding approach. We present the design and evaluation of a RLLS built for the LANL two-stage gas gun. Targets for the gun are made of PMMA and assembled to form a liquid containment cell with a volume of approximately 25 cc. The compatibility of materials was a major consideration in the design of the system, particularly for its use with highly concentrated hydrogen peroxide. Teflon and 304-stainless steel were the two most compatible materials with the materials to be tested. Teflon valves and tubing, as well as stainless steel tubing, were used to handle the liquid, along with a stainless steel reservoir. Preliminary testing was done to ensure proper flow rate and safety. The system has been used to successfully load 97.5 percent hydrogen peroxide into a target cell just prior to a successful multiple magnetic gauge experiment. TV cameras on the target verified the bubble-free filling operation.
High-speed rail markets, infrastructure investments and manufacturing capabilities.

DOT National Transportation Integrated Search

2012-09-01

Driven by increasing demand for passenger transportation and congestion in key corridors in the U.S., such as in California, the Northeast, Florida and parts of the Midwest, the U.S. has embarked on various initiatives to examine alternative solution...
INTERIOR OF BOILER BUILDING, FIRST LEVEL, EAST SIDE, SHOWING STEAMDRIVEN ...

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

INTERIOR OF BOILER BUILDING, FIRST LEVEL, EAST SIDE, SHOWING STEAM-DRIVEN PISTON PUMPS FOR FUEL OIL, CAMERA FACING EAST. - New Haven Rail Yard, Central Steam Plant and Oil Storage, Vicinity of Union Avenue, New Haven, New Haven County, CT
Foam-Mixing-And-Dispensing Machine

NASA Technical Reports Server (NTRS)

Chong, Keith Y.; Toombs, Gordon R.; Jackson, Richard J.

1996-01-01

Time-and-money-saving machine produces consistent, homogeneously mixed foam, enhancing production efficiency. Automatically mixes and dispenses polyurethane foam in quantities specified by weight. Consists of cart-mounted, air-driven proportioning unit; air-activated mechanical mixing gun; programmable timer/counter, and controller.
Magnetized Target Fusion Propulsion: Plasma Injectors for MTF Guns

NASA Technical Reports Server (NTRS)

Griffin, Steven T.

2003-01-01

To achieve increased payload size and decreased trip time for interplanetary travel, a low mass, high specific impulse, high thrust propulsion system is required. This suggests the need for research into fusion as a source of power and high temperature plasma. The plasma would be deflected by magnetic fields to provide thrust. Magnetized Target Fusion (MTF) research consists of several related investigations into these topics. These include the orientation and timing of the plasma guns and the convergence and interface development of the "pusher" plasma. Computer simulations of the gun as it relates to plasma initiation and repeatability are under investigation. One of the items under development is the plasma injector. This is a surface breakdown driven plasma generator designed to function at very low pressures. The performance, operating conditions and limitations of these injectors need to be determined.
Structure of propagating arc in a magneto-hydrodynamic rail plasma actuator

NASA Astrophysics Data System (ADS)

Gray, Miles D.; Choi, Young-Joon; Sirohi, Jayant; Raja, Laxminarayan L.

2016-01-01

The spatio-temporal evolution of a magnetically driven arc in a rail plasma flow actuator has been characterized with high-speed imaging, electrical measurements, and spectroscopy. The arc draws a peak current of ~1 kA. High-speed framing cameras were used to observe the complex arc propagation phenomenon. In particular, the anode and cathode roots were observed to have different modes of transit, which resulted in distinct types of electrode degradation on the anode and cathode surfaces. Observations of the arc electrical properties and induced magnetic fields are used to explain the transit mechanism of the arc. Emission spectroscopy revealed the arc temperature and species composition as a function of transit distance of the arc. The results obtained offer significant insights into the electromagnetic properties of the arc-rail system as well as arc-surface interaction phenomena in a propagating arc.
In-State and Interstate Associations Between Gun Shows and Firearm Deaths and Injuries: A Quasi-experimental Study.

PubMed

Matthay, Ellicott C; Galin, Jessica; Rudolph, Kara E; Farkas, Kriszta; Wintemute, Garen J; Ahern, Jennifer

2017-12-19

Gun shows are an important source of firearms, but no adequately powered studies have examined whether they are associated with increases in firearm injuries. To determine whether gun shows are associated with short-term increases in local firearm injuries and whether this association differs by the state in which the gun show is held. Quasi-experimental. California. Persons in California within driving distance of gun shows. Gun shows in California and Nevada between 2005 and 2013 (n = 915 shows) and rates of firearm-related deaths, emergency department visits, and inpatient hospitalizations in California. Compared with the 2 weeks before, postshow firearm injury rates remained stable in regions near California gun shows but increased from 0.67 injuries (95% CI, 0.55 to 0.80 injuries) to 1.14 injuries (CI, 0.97 to 1.30 injuries) per 100 000 persons in regions near Nevada shows. After adjustment for seasonality and clustering, California shows were not associated with increases in local firearm injuries (rate ratio [RR], 0.99 [CI, 0.97 to 1.02]) but Nevada shows were associated with increased injuries in California (RR, 1.69 [CI, 1.16 to 2.45]). The pre-post difference was significantly higher for Nevada shows than California shows (ratio of RRs, 1.70 [CI, 1.17 to 2.47]). The Nevada association was driven by significant increases in firearm injuries from interpersonal violence (RR, 2.23 [CI, 1.01 to 4.89]) but corresponded to a small increase in absolute numbers. Nonfirearm injuries served as a negative control and were not associated with California or Nevada gun shows. Results were robust to sensitivity analyses. Firearm injuries were examined only in California, and gun show occurrence was not randomized. Gun shows in Nevada, but not California, were associated with local, short-term increases in firearm injuries in California. Differing associations for California versus Nevada gun shows may be due to California's stricter firearm regulations. National Institutes of Health; University of California, Berkeley; and Heising-Simons Foundation.
Toward a terahertz-driven electron gun

PubMed Central

Huang, W. Ronny; Nanni, Emilio A.; Ravi, Koustuban; Hong, Kyung-Han; Fallahi, Arya; Wong, Liang Jie; Keathley, Phillip D.; Zapata, Luis E.; Kärtner, Franz X.

2015-01-01

Femtosecond electron bunches with keV energies and eV energy spread are needed by condensed matter physicists to resolve state transitions in carbon nanotubes, molecular structures, organic salts, and charge density wave materials. These semirelativistic electron sources are not only of interest for ultrafast electron diffraction, but also for electron energy-loss spectroscopy and as a seed for x-ray FELs. Thus far, the output energy spread (hence pulse duration) of ultrafast electron guns has been limited by the achievable electric field at the surface of the emitter, which is 10 MV/m for DC guns and 200 MV/m for RF guns. A single-cycle THz electron gun provides a unique opportunity to not only achieve GV/m surface electric fields but also with relatively low THz pulse energies, since a single-cycle transform-limited waveform is the most efficient way to achieve intense electric fields. Here, electron bunches of 50 fC from a flat copper photocathode are accelerated from rest to tens of eV by a microjoule THz pulse with peak electric field of 72 MV/m at 1 kHz repetition rate. We show that scaling to the readily-available GV/m THz field regime would translate to monoenergetic electron beams of ~100 keV. PMID:26486697
The Cascading Impacts of Technology Selection: Incorporating Ruby on Rails into ECHO

NASA Astrophysics Data System (ADS)

Pilone, D.; Cechini, M.

2010-12-01

NASA’s Earth Observing System (EOS) ClearingHOuse (ECHO) is a SOA based Earth Science Data search and order system implemented in Java with one significant exception: the web client used by 98% of our users is written in Perl. After several decades of maintenance the Perl based application had reached the end of its serviceable life and ECHO was tasked with implementing a replacement. Despite a broad investment in Java, the ECHO team conducted a survey of modern development technologies including Flex, Python/Django, JSF2/Spring and Ruby on Rails. The team ultimately chose Ruby on Rails (RoR) with Cucumber for testing due to its perceived applicability to web application development and corresponding development efficiency gains. Both positive and negative impacts on the entire ECHO team, including our stakeholders, were immediate and sometimes subtle. The technology selection caused shifts in our architecture and design, development and deployment procedures, requirement definition approach, testing approach, and, somewhat surprisingly, our project team structure and software process. This presentation discusses our experiences, including technical, process, and psychological, using RoR on a production system. During this session we will discuss: - Real impacts of introducing a dynamic language to a Java team - Real and perceived efficiency advantages - Impediments to adoption and effectiveness - Impacts of transition from Test Driven Development to Behavior Driven Development - Leveraging Cucumber to provide fully executable requirement documents - Impacts on team structure and roles

Optimizing preventive maintenance policy: A data-driven application for a light rail braking system.

PubMed

Corman, Francesco; Kraijema, Sander; Godjevac, Milinko; Lodewijks, Gabriel

2017-10-01

This article presents a case study determining the optimal preventive maintenance policy for a light rail rolling stock system in terms of reliability, availability, and maintenance costs. The maintenance policy defines one of the three predefined preventive maintenance actions at fixed time-based intervals for each of the subsystems of the braking system. Based on work, maintenance, and failure data, we model the reliability degradation of the system and its subsystems under the current maintenance policy by a Weibull distribution. We then analytically determine the relation between reliability, availability, and maintenance costs. We validate the model against recorded reliability and availability and get further insights by a dedicated sensitivity analysis. The model is then used in a sequential optimization framework determining preventive maintenance intervals to improve on the key performance indicators. We show the potential of data-driven modelling to determine optimal maintenance policy: same system availability and reliability can be achieved with 30% maintenance cost reduction, by prolonging the intervals and re-grouping maintenance actions.
Optimizing preventive maintenance policy: A data-driven application for a light rail braking system

PubMed Central

Corman, Francesco; Kraijema, Sander; Godjevac, Milinko; Lodewijks, Gabriel

2017-01-01

This article presents a case study determining the optimal preventive maintenance policy for a light rail rolling stock system in terms of reliability, availability, and maintenance costs. The maintenance policy defines one of the three predefined preventive maintenance actions at fixed time-based intervals for each of the subsystems of the braking system. Based on work, maintenance, and failure data, we model the reliability degradation of the system and its subsystems under the current maintenance policy by a Weibull distribution. We then analytically determine the relation between reliability, availability, and maintenance costs. We validate the model against recorded reliability and availability and get further insights by a dedicated sensitivity analysis. The model is then used in a sequential optimization framework determining preventive maintenance intervals to improve on the key performance indicators. We show the potential of data-driven modelling to determine optimal maintenance policy: same system availability and reliability can be achieved with 30% maintenance cost reduction, by prolonging the intervals and re-grouping maintenance actions. PMID:29278245
Shielding requirements for the Space Station habitability modules

NASA Technical Reports Server (NTRS)

Avans, Sherman L.; Horn, Jennifer R.; Williamsen, Joel E.

1990-01-01

The design, analysis, development, and tests of the total meteoroid/debris protection system for the Space Station Freedom habitability modules, such as the habitation module, the laboratory module, and the node structures, are described. Design requirements are discussed along with development efforts, including a combination of hypervelocity testing and analyses. Computer hydrocode analysis of hypervelocity impact phenomena associated with Space Station habitability structures is covered and the use of optimization techniques, engineering models, and parametric analyses is assessed. Explosive rail gun development efforts and protective capability and damage tolerance of multilayer insulation due to meteoroid/debris impact are considered. It is concluded that anticipated changes in the debris environment definition and requirements will require rescoping the tests and analysis required to develop a protection system.
Experiment to Form and Characterize a Section of a Spherically Imploding Plasma Liner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, S. C.; Langendorf, S. J.; Yates, K. C.

Here, we describe an experiment to form and characterize a section of a spherically imploding plasma liner by merging six supersonic plasma jets that are launched by newly designed contoured-gap coaxial plasma guns. This experiment is a prelude to forming a fully spherical imploding plasma liner using many dozens of plasma guns, as a standoff driver for plasma-jet-driven magneto-inertial fusion. The objectives of the six-jet experiments are to assess the evolution and scalings of liner Mach number and uniformity, which are important metrics for spherically imploding plasma liners to compress magnetized target plasmas to fusion conditions. Lastly, this article describesmore » the design of the coaxial plasma guns, experimental characterization of the plasma jets, six-jet experimental setup and diagnostics, initial diagnostic data from three- and six-jet experiments, and the high-level objectives of associated numerical modeling.« less
Experiment to Form and Characterize a Section of a Spherically Imploding Plasma Liner

DOE PAGES

Hsu, S. C.; Langendorf, S. J.; Yates, K. C.; ...

2017-12-18

Here, we describe an experiment to form and characterize a section of a spherically imploding plasma liner by merging six supersonic plasma jets that are launched by newly designed contoured-gap coaxial plasma guns. This experiment is a prelude to forming a fully spherical imploding plasma liner using many dozens of plasma guns, as a standoff driver for plasma-jet-driven magneto-inertial fusion. The objectives of the six-jet experiments are to assess the evolution and scalings of liner Mach number and uniformity, which are important metrics for spherically imploding plasma liners to compress magnetized target plasmas to fusion conditions. Lastly, this article describesmore » the design of the coaxial plasma guns, experimental characterization of the plasma jets, six-jet experimental setup and diagnostics, initial diagnostic data from three- and six-jet experiments, and the high-level objectives of associated numerical modeling.« less
36 CFR § 1001.4 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., vessels, mechanical modes of conveyance, or food/beverage containers allowed to enter, be brought into... snow, having a curb weight of not more than 1000 pounds (450 kg), driven by a track or tracks in... exclusively upon stationary rails or track. Vessel means every type or description of craft, other than a...
36 CFR 1001.4 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., vessels, mechanical modes of conveyance, or food/beverage containers allowed to enter, be brought into... snow, having a curb weight of not more than 1000 pounds (450 kg), driven by a track or tracks in... exclusively upon stationary rails or track. Vessel means every type or description of craft, other than a...
36 CFR 1001.4 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., vessels, mechanical modes of conveyance, or food/beverage containers allowed to enter, be brought into... snow, having a curb weight of not more than 1000 pounds (450 kg), driven by a track or tracks in... exclusively upon stationary rails or track. Vessel means every type or description of craft, other than a...
36 CFR 1001.4 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., vessels, mechanical modes of conveyance, or food/beverage containers allowed to enter, be brought into... snow, having a curb weight of not more than 1000 pounds (450 kg), driven by a track or tracks in... exclusively upon stationary rails or track. Vessel means every type or description of craft, other than a...
ARC-2006-ACD06-0177-011

NASA Image and Video Library

2006-10-18

Ames Hypersonic Free Flight Aerodynamic Facility is used for research on gas dynamic problems of atmospheric entry. High relative speeds are achieved by launching models (in sabots if necessary) from high-speed guns into a countercurrent hypersonic air stream (14,000 ft/sec) driven by combustion-powered shock tube.
Design and optimization of surface profilometer based on coplanar guide rail

NASA Astrophysics Data System (ADS)

Chen, Shuai; Dai, Yifan; Hu, Hao; Tie, Guipeng

2017-10-01

In order to implement the sub-micron precision measurement, a surface profilometer which based on the coplanar guide rail is designed. This profilometer adopts the open type air floating load and is driven by the magnetic force. As to achieve sub-micron accuracy, the flatness of granite guide working face and aerodynamic block are both processed to the micron level based on the homogenization of air flotation film theory. Permanent magnet which could reduce the influence of the driving disturbance to the measurement accuracy is used as the driving part. In this paper, the bearing capacity and the air floating stiffness of air floating block are both simulated and analyzed as to optimize the design parameters firstly. The layout and magnetic force of the magnet are also simulated. According to the simulation results, type selection and the position arrangement of the magnets are then confirmed. The test results on the experimental platform show that the surface profilometer based on coplanar guide rail possess the basis for realizing the submicron precision measurement.
Multichannel fiber laser Doppler vibrometer studies of low momentum and hypervelocity impacts

NASA Astrophysics Data System (ADS)

Posada-Roman, Julio E.; Jackson, David A.; Cole, Mike J.; Garcia-Souto, Jose A.

2017-12-01

A multichannel optical fiber laser Doppler vibrometer was demonstrated with the capability of making simultaneous non-contact measurements of impacts at 3 different locations. Two sets of measurements were performed, firstly using small ball bearings (1 mm-5.5 mm) falling under gravity and secondly using small projectiles (1 mm) fired from an extremely high velocity light gas gun (LGG) with speeds in the range 1 km/s-8 km/s. Determination of impact damage is important for industries such as aerospace, military and rail, where the effect of an impact on the structure can result in a major structural damage. To our knowledge the research reported here demonstrates the first trials of a multichannel fiber laser Doppler vibrometer being used to detect hypervelocity impacts.
The Feasibility of Railgun Horizontal-Launch Assist

NASA Technical Reports Server (NTRS)

Youngquist, Robert C.; Cox, Robert B.

2011-01-01

Railguns typically operate for a few milliseconds, supplying thousands of G's of acceleration to a small projectile, resulting in exceptional speeds. This paper argues through analysis and experiment, that this "standard" technology can be modified to provide 2-3 G's acceleration to a relatively heavy launch vehicle for a time period exceeding several seconds, yielding a launch assist velocity in excess of Mach 1. The key insight here is that an efficient rail gun operates at a speed approximately given by the system resistance divided by the inductance gradient, which can be tailored because recent MOSFET and ultra-capacitor advances allow very low total power supply resistances with high capacitance and augmented railgun architectures provide a scalable inductance gradient. Consequently, it should now be possible to construct a horizontal launch assist system utilizing railgun based architecture.
Control system for maximum use of adhesive forces of a railway vehicle in a tractive mode

NASA Astrophysics Data System (ADS)

Spiryagin, Maksym; Lee, Kwan Soo; Yoo, Hong Hee

2008-04-01

The realization of maximum adhesive forces for a railway vehicle is a very difficult process, because it involves using tractive efforts and depends on friction characteristics in the contact zone between wheels and rails. Tractive efforts are realized by means of tractive torques of motors, and their maximum values can provide negative effects such as slip and skid. These situations usually happen when information about friction conditions is lacking. The negative processes have a major influence on wearing of contact bodies and tractive units. Therefore, many existing control systems for vehicles use an effect of a prediction of a friction coefficient between wheels and rails because measuring a friction coefficient at the moment of running vehicle movement is very difficult. One of the ways to solve this task is to use noise spectrum analysis for friction coefficient detection. This noise phenomenon has not been clearly studied and analyzed. In this paper, we propose an adhesion control system of railway vehicles based on an observer, which allows one to determine the maximum tractive torque based on the optimal adhesive force between the wheels (wheel pair) of a railway vehicle and rails (rail track) depending on weight load from a wheel to a rail, friction conditions in the contact zone, a lateral displacement of wheel set and wheel sleep. As a result, it allows a railway vehicle to be driven in a tractive mode by the maximum adhesion force for real friction conditions.
Low-voltage analog front-end processor design for ISFET-based sensor and H+ sensing applications

NASA Astrophysics Data System (ADS)

Chung, Wen-Yaw; Yang, Chung-Huang; Peng, Kang-Chu; Yeh, M. H.

2003-04-01

This paper presents a modular-based low-voltage analog-front-end processor design in a 0.5mm double-poly double-metal CMOS technology for Ion Sensitive Field Effect Transistor (ISFET)-based sensor and H+ sensing applications. To meet the potentiometric response of the ISFET that is proportional to various H+ concentrations, the constant-voltage and constant current (CVCS) testing configuration has been used. Low-voltage design skills such as bulk-driven input pair, folded-cascode amplifier, bootstrap switch control circuits have been designed and integrated for 1.5V supply and nearly rail-to-rail analog to digital signal processing. Core modules consist of an 8-bit two-step analog-digital converter and bulk-driven pre-amplifiers have been developed in this research. The experimental results show that the proposed circuitry has an acceptable linearity to 0.1 pH-H+ sensing conversions with the buffer solution in the range of pH2 to pH12. The processor has a potential usage in battery-operated and portable healthcare devices and environmental monitoring applications.
Laser-free RF-gun as a combined source of THz and ps-sub-ps X-rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agustsson, R.; Boucher, S.; Finn, O.

A coherent, mm-sub-mm-wave source driven by a RF electron gun is proposed for wide research applications as well as auxiliary inspection and screening, safe imaging, cancer diagnostics, surface defectoscopy, and enhanced time-domain spectroscopy. It allows generation of high peak and average THz-sub-THz radiation power provided by beam pre-bunching and chirping in the RF gun followed by microbunching in magnetic compressor, and resonant Cherenkov radiation of an essentially flat beam in a robust, ~inch-long, planar, mm-sub-mm gap structure. The proof-of-principle has been successfully demonstrated in Phase I on a 5 MeV beam of L-band thermionic injector of Idaho Accelerator Center. Themore » system can also deliver an intense, ps-sub-ps bursts of low-to-moderate dose of relativistic electrons and X-ray radiation produced by the same beam required for pulsed radiolysis as well as to enhance screening efficiency, throughput and safety.« less
Laser-free RF-gun as a combined source of THz and ps-sub-ps X-rays

DOE PAGES

Agustsson, R.; Boucher, S.; Finn, O.; ...

2015-01-01

A coherent, mm-sub-mm-wave source driven by a RF electron gun is proposed for wide research applications as well as auxiliary inspection and screening, safe imaging, cancer diagnostics, surface defectoscopy, and enhanced time-domain spectroscopy. It allows generation of high peak and average THz-sub-THz radiation power provided by beam pre-bunching and chirping in the RF gun followed by microbunching in magnetic compressor, and resonant Cherenkov radiation of an essentially flat beam in a robust, ~inch-long, planar, mm-sub-mm gap structure. The proof-of-principle has been successfully demonstrated in Phase I on a 5 MeV beam of L-band thermionic injector of Idaho Accelerator Center. Themore » system can also deliver an intense, ps-sub-ps bursts of low-to-moderate dose of relativistic electrons and X-ray radiation produced by the same beam required for pulsed radiolysis as well as to enhance screening efficiency, throughput and safety.« less
Railway bogie vibration analysis by mathematical simulation model and a scaled four-wheel railway bogie set

NASA Astrophysics Data System (ADS)

Visayataksin, Noppharat; Sooklamai, Manon

2018-01-01

The bogie is the part that connects and transfers all the load from the vehicle body onto the railway track; interestingly the interaction between wheels and rails is the critical point for derailment of the rail vehicles. However, observing or experimenting with real bogies on rail vehicles is impossible due to the operational rules and safety concerns. Therefore, this research aimed to develop a vibration analysis set for a four-wheel railway bogie by constructing a four-wheel bogie with scale of 1:4.5. The bogie structures, including wheels and axles, were made from an aluminium alloy, equipped with springs and dampers. The bogie was driven by an electric motor using 4 round wheels instead of 2 straight rails, with linear velocity between 0 to 11.22 m/s. The data collected from the vibration analysis set was compared to the mathematical simulation model to investigate the vibration behavior of the bogie, especially the hunting motion. The results showed that vibration behavior from a scaled four-wheel railway bogie set significantly agreed with the mathematical simulation model in terms of displacement and hunting frequency. The critical speed of the wheelset was found by executing the mathematical simulation model at 13 m/s.
A locomotive-track coupled vertical dynamics model with gear transmissions

NASA Astrophysics Data System (ADS)

Chen, Zaigang; Zhai, Wanming; Wang, Kaiyun

2017-02-01

A gear transmission system is a key element in a locomotive for the transmission of traction or braking forces between the motor and the wheel-rail interface. Its dynamic performance has a direct effect on the operational reliability of the locomotive and its components. This paper proposes a comprehensive locomotive-track coupled vertical dynamics model, in which the locomotive is driven by axle-hung motors. In this coupled dynamics model, the dynamic interactions between the gear transmission system and the other components, e.g. motor and wheelset, are considered based on the detailed analysis of its structural properties and working mechanism. Thus, the mechanical transmission system for power delivery from the motor to the wheelset via gear transmission is coupled with a traditional locomotive-track dynamics system via the wheel-rail contact interface and the gear mesh interface. This developed dynamics model enables investigations of the dynamic performance of the entire dynamics system under the excitations from the wheel-rail contact interface and/or the gear mesh interface. Dynamic interactions are demonstrated by numerical simulations using this dynamics model. The results indicate that both of the excitations from the wheel-rail contact interface and the gear mesh interface have a significant effect on the dynamic responses of the components in this coupled dynamics system.
A gas-loading system for LANL two-stage gas guns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gibson, Lloyd Lee; Bartram, Brian Douglas; Dattelbaum, Dana Mcgraw

A novel gas loading system was designed for the specific application of remotely loading high purity gases into targets for gas-gun driven plate impact experiments. The high purity gases are loaded into well-defined target configurations to obtain Hugoniot states in the gas phase at greater than ambient pressures.The small volume of the gas samples is challenging, as slight changing in the ambient temperature result in measurable pressure changes. Therefore, the ability to load a gas gun target and continually monitor the sample pressure prior to firing provides the most stable and reliable target fielding approach. We present the design andmore » evaluation of a gas loading system built for the LANL 50 mm bore two-stage light gas gun. Targets for the gun are made of 6061 Al or OFHC Cu, and assembled to form a gas containment cell with a volume of approximately 1.38 cc. The compatibility of materials was a major consideration in the design of the system, particularly for its use with corrosive gases. Piping and valves are stainless steel with wetted seals made from Kalrez® and Teflon®. Preliminary testing was completed to ensure proper flow rate and that the proper safety controls were in place. The system has been used to successfully load Ar, Kr, Xe, and anhydrous ammonia with purities of up to 99.999 percent. The design of the system and example data from the plate impact experiments will be shown.« less

A gas-loading system for LANL two-stage gas guns

NASA Astrophysics Data System (ADS)

Gibson, L. L.; Bartram, B. D.; Dattelbaum, D. M.; Lang, J. M.; Morris, J. S.

2017-01-01

A novel gas loading system was designed for the specific application of remotely loading high purity gases into targets for gas-gun driven plate impact experiments. The high purity gases are loaded into well-defined target configurations to obtain Hugoniot states in the gas phase at greater than ambient pressures. The small volume of the gas samples is challenging, as slight changing in the ambient temperature result in measurable pressure changes. Therefore, the ability to load a gas gun target and continually monitor the sample pressure prior to firing provides the most stable and reliable target fielding approach. We present the design and evaluation of a gas loading system built for the LANL 50 mm bore two-stage light gas gun. Targets for the gun are made of 6061 Al or OFHC Cu, and assembled to form a gas containment cell with a volume of approximately 1.38 cc. The compatibility of materials was a major consideration in the design of the system, particularly for its use with corrosive gases. Piping and valves are stainless steel with wetted seals made from Kalrez® and Teflon®. Preliminary testing was completed to ensure proper flow rate and that the proper safety controls were in place. The system has been used to successfully load Ar, Kr, Xe, and anhydrous ammonia with purities of up to 99.999 percent. The design of the system and example data from the plate impact experiments will be shown.
29 CFR 1926.302 - Power-operated hand tools.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the source of supply or branch line to reduce pressure in case of hose failure. (8) Airless spray guns... the open barrel end. (6) Loaded tools shall not be left unattended. (7) Fasteners shall not be driven...-hardened steel, glass block, live rock, face brick, or hollow tile. (8) Driving into materials easily...
29 CFR 1926.302 - Power-operated hand tools.

Code of Federal Regulations, 2013 CFR

2013-07-01

... the source of supply or branch line to reduce pressure in case of hose failure. (8) Airless spray guns... the open barrel end. (6) Loaded tools shall not be left unattended. (7) Fasteners shall not be driven...-hardened steel, glass block, live rock, face brick, or hollow tile. (8) Driving into materials easily...
29 CFR 1926.302 - Power-operated hand tools.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the source of supply or branch line to reduce pressure in case of hose failure. (8) Airless spray guns... the open barrel end. (6) Loaded tools shall not be left unattended. (7) Fasteners shall not be driven...-hardened steel, glass block, live rock, face brick, or hollow tile. (8) Driving into materials easily...
29 CFR 1926.302 - Power-operated hand tools.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the source of supply or branch line to reduce pressure in case of hose failure. (8) Airless spray guns... the open barrel end. (6) Loaded tools shall not be left unattended. (7) Fasteners shall not be driven...-hardened steel, glass block, live rock, face brick, or hollow tile. (8) Driving into materials easily...
29 CFR 1926.302 - Power-operated hand tools.

Code of Federal Regulations, 2014 CFR

2014-07-01

... the source of supply or branch line to reduce pressure in case of hose failure. (8) Airless spray guns... the open barrel end. (6) Loaded tools shall not be left unattended. (7) Fasteners shall not be driven...-hardened steel, glass block, live rock, face brick, or hollow tile. (8) Driving into materials easily...
Suppression of MHD fluctuations leading to improved confinement in a gun-driven spheromak.

PubMed

McLean, H S; Woodruff, S; Hooper, E B; Bulmer, R H; Hill, D N; Holcomb, C; Moller, J; Stallard, B W; Wood, R D; Wang, Z

2002-03-25

Magnetic fluctuations have been reduced to approximately 1% during discharges on the Sustained Spheromak Physics Experiment by shaping the spatial distribution of the bias magnetic flux in the device. In the resulting quiescent regime, the safety factor profile is nearly flat in the plasma and the dominant ideal and resistive MHD modes are greatly reduced. During this period, the temperature profile is peaked at the magnetic axis and maps onto magnetic flux contours. Energy confinement time is improved over previous reports in a driven spheromak.
Effects of the current boundary conditions at the plasma-gun gap on density in SSPX

NASA Astrophysics Data System (ADS)

Kolesnikov, Roman; Lodestro, L. L.; Meyer, W. H.

2012-10-01

The Sustained Spheromak Physics Experiment (SSPX) was a toroidal magnetic-confinement device without toroidal magnetic-field coils or a central transformer but which generated core-plasma currents by dynamo processes driven by coaxial plasma-gun injection into a flux-conserving vessel. Record electron temperatures in a spheromak (Te˜500eV) were achieved, and final results of the SSPX program were reported in [1]. Plasma density, which depended strongly on wall conditions, was an important parameter in SSPX. It was observed that density rises with Igun and that confinement improved as the density was lowered. Shortly after the last experiments, a new feature was added to the Corsica code's solver used to reconstruct SSPX equilibria. Motivated by n=0 fields observed in NIMROD simulations of SSPX, an insulating boundary condition was implemented at the plasma-gun gap. Using this option we will perform new reconstructions of SSPX equilibria and look for correlations between the location of the separatrix (which moves up the gun wall and onto the insulating gap as Igun increases) and plasma density and magnetic-flux amplification [2].[4pt] [1] H. S. McLean, APS, DPP, Dallas, TX, 2008.[0pt] [2] E. B. Hooper et al., Nucl. Fusion 47, 1064 (2007).
Infrared countermeasure flare performance measurements using a gas gun

NASA Astrophysics Data System (ADS)

Krishnamoorthy, Lakshmanan; Stringer, Michael; Taylor, Mark R. G.; Kollias, S.

2004-12-01

A unique and cost effective measurement facility called the Reusable Aerodynamic Flare Ejection Capability (RAFEC) has been developed at the Defence Science and Technology Organisation (DSTO), Australia. The RAFEC system involves the use of a reusable, carrier projectile that is launched from a 10 inch, nitrogen driven gas gun. The IRCM flare is loaded in the carrier projectile and the gas gun launches the carrier projectile with a known velocity of between approximately 350 to 650 knots. At a pre-determined time after firing and in the field of view of the measuring instrumentation, the flare is ejected from the carrier projectile for performance measurements to be undertaken. The temporal, spatial and spectral quantities were accomplished with the instruments fielded around the gas gun line of fire and the trajectory is derived from the spatial measurements. The data will be used for hardware in the loop simulations and modelling. Further improvements such as; (1) multiple (maximum of three) flare ejection, (2) 1"x1"x8" format flares made to the carrier projectile, and (3) design and manufacture of the puston, a new item of firing hardware to obtain lower muzzle velocities have enhanced the RAFEC capability. Thus the RAFEC system provides a more realistic IRCM performance measurement capability as it incorporates the deceleration effects experienced by the flare on deployment.
Cusp-Gun Sixth-Harmonic Slotted Gyrotron

NASA Astrophysics Data System (ADS)

Stutzman, R. C.; McDermott, D. B.; Hirata Luhmann, Y., Jr.; Gallagher, D. A.; Spencer, T. A.

2000-10-01

A high-harmonic slotted gyrotron has been constructed at UC Davis to be driven by a 70 kV, 3.5 A, axis-encircling electron beam from a Northrop Grumman Cusp gun. The 94 GHz, slotted sixth-harmonic gyrotron is predicted to generate 50 kW with an efficiency of 20%. Using the profile of the adiabatic field reversal from the UC Davis superconducting test-magnet, EGUN simulations predict that an axis-encircling electron beam will be generated with an axial velocity spread of Δ v_z/v_z=10% for the desired velocity ratio of α =v_z/v_z=1.5. The design will also be presented for an 8th-harmonic W-band gyrotron whose magnetic field can be supplied by a lightweight permanent magnet.
Fast discharge in a plasma gun with hemispherical insulator

NASA Astrophysics Data System (ADS)

Antsiferov, P. S.; Dorokhin, L. A.; Sidelnikov, Yu. V.; Koshelev, K. N.

2009-05-01

A method of creation of hot dense plasma is proposed. It is based on cumulation of a shockwave, which originates on a hemispherical surface of insulator of plasma gun. The results of first experiments are presented. The shock wave is driven by fast electrical discharge (dI /dt>1012 A/s). The inductive storage with semiconductor opening switch is used as a current driver. Time resolved pin-hole images and vacuum ultraviolet (vuv) spectra are studied. Shockwaves from hemispherical insulator with 4 mm radius create plasma with a form of column about 1 mm diameter and 3-4 mm length. vuv spectra contain the lines of Ar ions that corresponds to the electron temperature about 20 eV. Possible practical application is discussed.
Formation of Imploding Plasma Liners for HEDP and MIF Application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Witherspoon, F. Douglas; Case, Andrew; Brockington, Samuel

Plasma jets with high density and velocity have a number of important applications in fusion energy and elsewhere, including plasma refueling, disruption mitigation in tokamaks, magnetized target fusion, injection of momentum into centrifugally confined mirrors, plasma thrusters, and high energy density plasmas (HEDP). In Magneto-Inertial Fusion (MIF), for example, an imploding material liner is used to compress a magnetized plasma to fusion conditions and to confine the resulting burning plasma inertially to obtain the necessary energy gain. The imploding shell may be solid, liquid, gaseous, or a combination of these states. The presence of the magnetic field in the targetmore » plasma suppresses thermal transport to the plasma shell, thus lowering the imploding power needed to compress the target to fusion conditions. This allows the required imploding momentum flux to be generated electromagnetically using off-the-shelf pulsed power technology. Practical schemes for standoff delivery of the imploding momentum flux are required and are open topics for research. One approach for accomplishing this, called plasma jet driven magneto-inertial fusion (PJMIF), uses a spherical array of pulsed plasma guns to create a spherically imploding shell of very high velocity, high momentum flux plasma. This approach requires development of plasma jet accelerators capable of achieving velocities of 50-200 km/s with very precise timing and density profiles, and with high total mass and density. Low-Z plasma jets would require the higher velocities, whereas very dense high-Z plasma shells could achieve the goal at velocities of only 50-100 km/s. In this report, we describe our work to develop the pulsed plasma gun technology needed for an experimental scientific exploration of the PJMIF concept, and also for the other applications mentioned earlier. The initial goal of a few hundred of hydrogen at 200 km/s was eventually replaced with accelerating 8000 μg of argon or xenon to 50 km/s for the Plasma Liner Experiment (PLX) at Los Alamos National Laboratory (LANL). Initial work used existing computational and analytical tools to develop and refine a specific plasma gun concept having a novel tapered coaxial electromagnetic accelerator contour with an array of symmetric ablative plasma injectors. The profile is designed to suppress the main barrier to success in coaxial guns, namely the blow-by instability in which the arc slips past and outruns the bulk of the plasma mass. Efforts to begin developing a set of annular non-ablative plasma injectors for the coaxial gun, in order to accelerate pure gases, resulted in development of linear parallel-plate MiniRailguns that turned out to work well as plasma guns in their own right and we subsequently chose them for an initial plasma liner experiment on the PLX facility at LANL. This choice was mainly driven by cost and schedule for that particular experiment, while longer term goals still projected use of coaxial guns for reactor-relevant applications for reasons of better symmetry, lower impurities, more compact plasma jet formation, and higher gun efficiency. Our efforts have focused mainly on 1) developing various plasma injection systems for both coax and linear railguns and ensuring they work reliably with the accelerator section, 2) developing a suite of plasma and gun diagnostics, 3) performing computational modeling to design and refine the plasma guns, 4) establishing a research facility dedicated to plasma gun development, and finally, 5) developing plasma guns and associated pulse power systems capable of achieving these goals and installing and testing the first two gun sets on the PLX facility at LANL. During the second funding cycle for this program, HyperV joined in a collaborative effort with LANL, the University of Alabama at Huntsville, and the University of New Mexico to perform a plasma liner experiment (PLX) to investigate the physics and technology of forming spherically imploding plasma liners. HyperV’s tasks focused on developing the plasma guns and associated pulse power systems required for the 30 gun experiment at LANL. Unfortunately, funding for the entire PLX collaborative project was terminated after only two years of the four year project due to program funding realignments which necessitated recompeting the project in midstream. Despite the loss of funding, HyperV installed two Mark1 guns and pulsed power systems on PLX, and jet characterization and merging experiments were subsequently successfully performed at LANL by the PLX Team. In parallel with those PLX experiments, HyperV continued its efforts to develop a plasma gun capable of meeting the PLX goal of 8 mg of argon at 50 km/s. HyperV was ultimately successful in this effort, demonstrating 10.8 mg at 52.8 km/s and 7.5 mg at 62.4 km/s with the Mark2 MiniRailgun.« less
6. Photograph of a photograph in possession of Rock Island ...

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

6. Photograph of a photograph in possession of Rock Island Arsenal Historical Office. FIRST FLOOR, EAST WING, SHOWING BELT-DRIVEN EQUIPMENT (LATHES, DRILLS, SCREW MACHINES) USED IN MACHINING COMPONENTS FOR ARTILLERY GUN CARRIAGES. DATED MAY 12, 1904. - Rock Island Arsenal, Building No. 108, Rodman Avenue between Third & Fourth Streets, Rock Island, Rock Island County, IL
Laboratory simulation of intact capture of cometary and asteroidal dust particles in ISAS

NASA Technical Reports Server (NTRS)

Fujiwara, A.; Nakamura, A.; Kadono, T.

1994-01-01

In order to develop a collector for intact capturing of cometary dust particles in the SOCCER mission and regolith dust particles released from asteroid surfaces by the impact of projectiles launched from a flying-by spacecraft, various kinds of materials as the collector candidates have been exposed to hypervelocity projectiles in our laboratory. Data based on the penetration characteristics of various materials (penetration depth, hole profile, effectiveness for intact capturing) are greatly increased. The materials tested for these simulation experiments include various kinds of low-density media and multisheet stacks; these are foamed plastics (polystyrene 0.01 g/cc), silica aerogels (0.04 g/cc), air (0.001 g/cc), liquid, and multisheet stack consisting of thin Al sheets (thickness 0.002 to 0.1 mm) or polyethylene sheets. Projectiles used are spheres or cylinders of nylon, polycarbonate, basalt, copper, iron, and volatile organics (e.g.,paradichlorobenzene) of size ranging from 30 micrometers to 1 cm launched by a two-stage light gas gun and a rail gun in ISAS at velocity up to about 7 km/s. Some results obtained by using nylon projectiles of velocity less than about 5 km/s are presented; the penetration depth vs. bulk density of the collector material for several kinds of materials and the velocity at which the projectiles begin to fragment vs. material density for foamed polystyrene.
Ruby on Rails Applications

NASA Technical Reports Server (NTRS)

Hochstadt, Jake

2011-01-01

Ruby on Rails is an open source web application framework for the Ruby programming language. The first application I built was a web application to manage and authenticate other applications. One of the main requirements for this application was a single sign-on service. This allowed authentication to be built in one location and be implemented in many different applications. For example, users would be able to login using their existing credentials, and be able to access other NASA applications without authenticating again. The second application I worked on was an internal qualification plan app. Previously, the viewing of employee qualifications was managed through Excel spread sheets. I built a database driven application to streamline the process of managing qualifications. Employees would be able to login securely to view, edit and update their personal qualifications.
Compact streak camera for the shock study of solids by using the high-pressure gas gun

NASA Astrophysics Data System (ADS)

Nagayama, Kunihito; Mori, Yasuhito

1993-01-01

For the precise observation of high-speed impact phenomena, a compact high-speed streak camera recording system has been developed. The system consists of a high-pressure gas gun, a streak camera, and a long-pulse dye laser. The gas gun installed in our laboratory has a muzzle of 40 mm in diameter, and a launch tube of 2 m long. Projectile velocity is measured by the laser beam cut method. The gun is capable of accelerating a 27 g projectile up to 500 m/s, if helium gas is used as a driver. The system has been designed on the principal idea that the precise optical measurement methods developed in other areas of research can be applied to the gun study. The streak camera is 300 mm in diameter, with a rectangular rotating mirror which is driven by an air turbine spindle. The attainable streak velocity is 3 mm/microsecond(s) . The size of the camera is rather small aiming at the portability and economy. Therefore, the streak velocity is relatively slower than the fast cameras, but it is possible to use low-sensitivity but high-resolution film as a recording medium. We have also constructed a pulsed dye laser of 25 - 30 microsecond(s) in duration. The laser can be used as a light source of observation. The advantage for the use of the laser will be multi-fold, i.e., good directivity, almost single frequency, and so on. The feasibility of the system has been demonstrated by performing several experiments.
Circle the Wagons & Bust out the Big Guns! Tame the "Wild West" of Distance Librarianship Using Quality Matters™ Benchmarks

ERIC Educational Resources Information Center

Pickens, Kathleen; Witte, Ginna

2015-01-01

The Quality Matters™ (QM) Program is utilized by over 700 colleges and universities to ensure that online course design meets standards imperative to student success in a Web-based classroom. Although a faculty-driven peer-review process, QM provides assessment from a student perspective, thereby identifying opportunities for improvement that may…
Overview of C-2U FRC Experimental Program and Plans for C-2W

NASA Astrophysics Data System (ADS)

Gota, H.; Binderbauer, M. W.; Tajima, T.; Putvinski, S.; Tuszewski, M.; Dettrick, S.; Korepanov, S.; Smirnov, A.; Thompson, M. C.; Yang, X.; Cappello, M.; Ivanov, A. A.; TAE Team

2016-10-01

Tri Alpha Energy's experimental program has been focused on a demonstration of reliable field-reversed configuration (FRC) formation and sustainment, driven by fast ions via high-power neutral-beam (NB) injection. The world's largest compact-toroid experimental devices, C-2 and C-2U, have successfully produced a well-stabilized, sustainable FRC plasma state with NB injection (input power, PNB 10 + MW; 15 keV hydrogen) and end-on coaxial plasma guns. Remarkable improvements in confinement and stability of FRC plasmas have led to further improved fast-ion build up; thereby, an advanced beam-driven FRC state has been produced and sustained for up to 5 + ms (longer than all characteristic system time scales), only limited by hardware and electric supply constraints such as NB and plasma-gun power supplies. To further improve the FRC performance the C-2U device is being replaced by C-2W featuring higher injected NB power, longer pulse duration as well as enhanced edge-biasing systems and substantially upgraded divertors. Main C-2U experimental results and key features of C-2W will be presented. Tri Alpha Energy, Inc.
Point-source helicity injection for ST plasma startup in Pegasus

NASA Astrophysics Data System (ADS)

Redd, A. J.; Battaglia, D. J.; Bongard, M. W.; Fonck, R. J.; Schlossberg, D. J.

2009-11-01

Plasma current guns are used as point-source DC helicity injectors for forming non-solenoidal tokamak plasmas in the Pegasus Toroidal Experiment. Discharges driven by this injection scheme have achieved Ip>= 100 kA using Iinj<= 4 kA. They form at the outboard midplane, transition to a tokamak-like equilibrium, and continue to grow inward as Ip increases due to helicity injection and outer- PF induction. The maximum Ip is determined by helicity balance (injection rate vs resistive dissipation) and a Taylor relaxation limit, in which Ip√ITF Iinj/w, where w is the radial thickness of the gun-driven edge. Preliminary experiments tentatively confirm these scalings with ITF, Iinj, and w, increasing confidence in this simple relaxation model. Adding solenoidal inductive drive during helicity injection can push Ip up to, but not beyond, the predicted relaxation limit, demonstrating that this is a hard performance limit. Present experiments are focused on increasing the injection voltage (i.e., helicity injection rate) and reducing w. Near-term goals are to further test scalings predicted by the simple relaxation model and to study in detail the observed bursty n=1 activity correlated with rapid increases in Ip.
THz and Sub-THz Capabilities of a Table-Top Radiation Source Driven by an RF Thermionic Electron Gun

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smirnov, Alexei V.; Agustsson, R.; Boucher, S.

Design features and experimental results are presented for a sub-mm wave source [1] based on APS RF thermionic electron gun. The setup includes compact alpha-magnet, quadrupoles, sub-mm-wave radiators, and THz optics. The sub-THz radiator is a planar, oversized structure with gratings. Source upgrade for generation frequencies above 1 THz is discussed. The THz radiator will use a short-period undulator having 1 T field amplitude, ~20 cm length, and integrated with a low-loss oversized waveguide. Both radiators are integrated with a miniature horn antenna and a small ~90°-degree in-vacuum bending magnet. The electron beamline is designed to operate different modes includingmore » conversion to a flat beam interacting efficiently with the radiator. The source can be used for cancer diagnostics, surface defectoscopy, and non-destructive testing. Sub-THz experiment demonstrated a good potential of a robust, table-top system for generation of a narrow bandwidth THz radiation. This setup can be considered as a prototype of a compact, laser-free, flexible source capable of generation of long trains of Sub-THz and THz pulses with repetition rates not available with laser-driven sources.« less

Recent results of studies of acceleration of compact toroids

NASA Astrophysics Data System (ADS)

Hammer, J. H.; Hartmen, C. W.; Eddleman, J.

1984-03-01

The observed gross stability and self-contained structure of compact toroids (CT's) give rise to the possibility, unique among magnetically confined plasmas, of translating CT's from their point of origin over distances many times their own length. This feature has led us to consider magnetic acceleration of CT's to directed kinetic energies much greater than their stored magnetic and thermal energies. A CT accelerator falls in the very broad gap between traditional particle accelerators at one extreme, which are limited in the number of particles per bunch by electrostatic repulsive forces, and mass accelerators such as rail guns at the other extreme, which accelerate many particles but are forced by the stress limitations of solids to far smaller accelerations. A typical CT has about a Coulomb of particles, weighs 10 micrograms and can be accelerated by magnetic forces of several tons, leading to an acceleration on the order of 10(11) gravities.
Concept definition study for an extremely large aerophysics range facility

NASA Technical Reports Server (NTRS)

Swift, H.; Witcofski, R.

1992-01-01

The development of a large aerophysical ballistic range facility is considered to study large-scale hypersonic flows at high Reynolds numbers for complex shapes. A two-stage light gas gun is considered for the hypervelocity launcher, and the extensive range tankage is discussed with respect to blast suppression, model disposition, and the sabot impact tank. A layout is given for the large aerophysics facility, and illustrations are provided for key elements such as the guide rail. The paper shows that such a facility could be used to launch models with diameters approaching 250 mm at velocities of 6.5 km/s with peak achievable accelerations of not more than 85.0 kgs. The envisioned range would provide gas-flow facilities capable of controlling the modeled quiescent atmospheric conditions. The facility is argued to be a feasible and important step in the investigation and experiment of such hypersonic vehicles as the National Aerospace Plane.
Parametric studies of North East Corridor rail passenger service between New York City and Washington, D. C.. [propulsive efficiency studies

NASA Technical Reports Server (NTRS)

Stallkamp, J. A.

1977-01-01

Speed profiles of rail passenger service between New York City and Washington, D.C. were developed and showed progressively fewer speed restrictions and increasing maximum speeds. The significant equipment characteristics include the portion of the total weight on driven axles, i.e., multiple unit (MU) cars versus locomotive hauled trains, and the short term tractive effort rating of the motors. The ratio of acceleration plus braking time to total time is provided for validation of the use of the short term propulsion equipment ratings. Absolute trip times are shown to be determined primarily by the allowed speed profile. Locomotive hauled train weights and lengths and the locomotive capabilities and characteristics that are required to make the performance of this type of train comparable to that of MU trains are given.
Mass sensitivity studies for an inductively driven railgun

NASA Astrophysics Data System (ADS)

Scanlon, J. J., III; Young, A. F.

1991-01-01

Those areas which result in substantial system mass reductions for an HPG (homopolar generator) driven EML (electromagnetic launcher) are identified. Sensitivity studies are performed by varying launch mass, peak acceleration, launcher efficiency, inductance gradient, injection velocity, barrel mass per unit length, fuel tankage and pump estimates, and component energy and power densities. Two major contributors to the system mass are the allowed number of shots per barrel versus the number required for the mission, and the barrel length. The effects of component performance parameters, such as friction coefficient, injection velocity, ablation coefficient, rail resistivity, armature voltage, peak acceleration, and inductance gradient on these two areas, are addressed.
Effects of multi-pulsed coaxial helicity injection on dynamics of spherical torus

NASA Astrophysics Data System (ADS)

Kanki, T.; Nagata, M.; Kagei, Y.

2012-10-01

The mechanism to rebuild the magnetic fields and to amplify the currents in the high-q spherical torus (ST) by the multi-pulsed coaxial helicity injection is investigated using the resistive nonlinear 3D-MHD simulations. During the driven phase, the dynamics is almost axisymmetric because the magnetic fluctuation level of n=0 mode compared with other higher modes is much larger. The toroidal current It is effectively amplified due to the merging of plasmoid ejected from the gun region with the pre-existing ST in the confinement region. The poloidal flux is not significantly amplified because the current sheet generated by the merging process does not rapidly decay. The negative toroidal flow vt is then induced in the direction of It around the central open flux column (OFC) region by inductive toroidal electric field Et (=-vzBr) because of the plasmoid ejection. The strong poloidal flow vz (=ErBt) is also driven from the gun to confinement region due to the Lorentz force. As the result of vz, the flow vortices associated with the dynamo effect are caused around the upper confinement region. During the decay phase, the closed field lines are regenerated due to the dissipation of magnetic fluctuations. The helical distortion of the OFC becomes small, and then ordered magnetic field structures without flows are built. Just after turning off the external electric field, the poloidal flow from the confinement to gun region is caused by the pressure gradients. The parallel current density λ concentrated in the OFC diffuses to the core region, but does not relax in the direction of the Taylor state due to the pressure gradients.
Characterizing the plasma of the Rotating Wall Machine

NASA Astrophysics Data System (ADS)

Hannum, David A.

The Rotating Wall Machine (RoWM) is a line-tied linear screw pinch built to study current-driven external kink modes. The plasma column is formed by an array of seven electrostatic washer guns which can also be biased to drive plasma current. The array allows independent control over the electron density ne and current density Jz profiles of the column. Internal measurements of the plasma have been made with singletip Langmuir and magnetic induction ("B-dot") probes for a range of bias currents (Ib = 0, 300, 500 A/gun). Streams from the individual guns are seen to merge at a distance of z ≈ 36 cm from the guns; the exact distance depends on the value of Ib. The density of the column is directly proportional to the Ohmic dissipation power, but the temperature stays at a low, uniform value (Te ≈ 3.5 eV) for each bias level. Electron densities are on the order of ne ˜10 20 m-3. The electron density expands radially (across the Bz guide field) as the plasma moves along the column, though the current density Jz mainly stays parallel to the field lines. The singletip Langmuir probe diagnostic is difficult to analyze for Ib = 500 A/gun plasmas and fails as Ib is raised beyond this level. Spectrographic analysis of the Halpha line indicates that the hydrogen plasmas are nearly fully ionized at each bias level. Azimuthal E x B rotation is axially and radially sheared; rotation slows as the plasma reaches the anode. Perpendicular diffusivity is consistent with the classical value, D⊥ ≈ 5 m2/sec, while parallel resistivity is seen to be twice the classical Spitzer value, 2 x 10-4 O m.
Performances of the Alpha-X RF gun on the PHIL accelerator at LAL

NASA Astrophysics Data System (ADS)

Vinatier, T.; Bruni, C.; Roux, R.; Brossard, J.; Chancé, S.; Cayla, J. N.; Chaumat, V.; Xu, G.; Monard, H.

2015-10-01

The Alpha-X RF-gun was designed to produce an ultra-short (<100 fs rms), 100 pC and 6.3 MeV electron beam with a normalized rms transverse emittance of 1π mm mrad for a gun peak accelerating field of 100 MV/m. Such beams will be required by the Alpha-X project, which aims to study a laser-driven plasma accelerator with a short wavelength accelerating medium. It has been demonstrated on PHIL (Photo-Injector at LAL) that the coaxial RF coupling, chosen to preserve the gun field cylindrical symmetry, is perfectly understood and allows reaching the required peak accelerating field of 100 MV/m giving beam energy of 6.3 MeV. Moreover, a quite low beam rms relative energy spread of 0.15% at 3.8 MeV has been measured, completely agreeing with simulations. Dark current, quantum efficiencies and dephasing curves measurements have also been performed. They all show high values of the field enhancement factor β, which can be explained by the preparation of the photocathodes. Finally, measurements on the transverse phase-space have been carried out, with some limitations given by the difficult modelization of one of the PHIL solenoid magnets and by the enlargement of the beam transverse dimensions due to the use of YAG screens. These measurements give a normalized rms transverse emittance around 5π mm mrad, which does not fulfill the requirement for the Alpha-X project.
In situ insights into shock-driven reactive flow

NASA Astrophysics Data System (ADS)

Dattelbaum, Dana

2017-06-01

Shock-driven reactions are commonplace. Examples include the detonation of high explosives, shock-driven dissociation of polymers, and transformation of carbon from graphite to diamond phases. The study of shock-driven chemical reactions is important for understanding reaction thresholds, their mechanisms and rates, and associated state sensitivities under the extreme conditions generated by shock compression. Reactions are distinguished by their thermicity - e.g. the volume and enthalpy changes along the reaction coordinate. A survey of the hallmarks of shock-driven reactivity for a variety of simple molecules and polymers will be presented, including benzene, acetylenes and nitriles, and formic acid. Many of the examples will illustrate the nature of the reactive flow through particle velocity wave profiles measured by in situ electromagnetic gauging in gas gun-driven plate impact experiments. General trends will be presented linking molecular moieties, shock temperatures, and reaction state sensitivities. Progress in applying bond-specific diagnostics will also be presented, including time-resolved Raman spectroscopy, and recent results of in situ x-ray diffraction of carbon at the Linac Coherent Light Souce (LCLS) free electron laser.
Autonomous health management for PMSM rail vehicles through demagnetization monitoring and prognosis control.

PubMed

Niu, Gang; Jiang, Junjie; Youn, Byeng D; Pecht, Michael

2018-01-01

Autonomous vehicles are playing an increasingly importance in support of a wide variety of critical events. This paper presents a novel autonomous health management scheme on rail vehicles driven by permanent magnet synchronous motors (PMSMs). Firstly, the PMSMs are modeled based on first principle to deduce the initial profile of pneumatic braking (p-braking) force, then which is utilized for real-time demagnetization monitoring and degradation prognosis through similarity-based theory and generate prognosis-enhanced p-braking force strategy for final optimal control. A case study is conducted to demonstrate the feasibility and benefit of using the real-time prognostics and health management (PHM) information in vehicle 'drive-brake' control automatically. The results show that accurate demagnetization monitoring, degradation prognosis, and real-time capability for control optimization can be obtained, which can effectively relieve brake shoe wear. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.
Electromagnetic Launchers and Guns. Phase 1

DTIC Science & Technology

1980-06-01

a high-speed maglev transportation system based on a linear synchronous motor (1,2,3). In 1975 Gerard K. O’Neill of Princeton University...fact that the very important railgun- homopolar launcher technology is already being pursued at Westinghouse and university of Texas, Austin. The...shown in Fig. 14 on the following page. There are three comparable options for energy storage: an engine-driven homopolar generator followed by an
Integrated thermal management of a hybrid electric vehicle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Traci, R.M.; Acebal, R.; Mohler, T.

1999-01-01

A thermal management methodology, based on the Vehicle Integrated Thermal Management Analysis Code (VITMAC), has been developed for a notional vehicle employing the All-Electric Combat Vehicle (AECV) concept. AECV uses a prime power source, such as a diesel, to provide mechanical energy which is converted to electrical energy and stored in a central energy storage system consisting of flywheels, batteries and/or capacitors. The combination of prime power and stored energy powers the vehicle drive system and also advanced weapons subsystems such as an ETC or EM gun, electrically driven lasers, an EM armor system and an active suspension. Every majormore » system is electrically driven with energy reclamation when possible from braking and gun recoil. Thermal management of such a complicated energy transfer and utilization system is a major design consideration due to the substantial heat rejection requirements. In the present paper, an overall integrated thermal management system (TMS) is described which accounts for energy losses from each subsystem component, accepts the heat using multiple coolant loops and expels the heat from the vehicle. VITMAC simulations are used to design the TMS and to demonstrate that a conventional TMS approach is capable of successfully handling vehicle heat rejection requirements under stressing operational conditions.« less
Optimal design of a piezoelectric transducer for exciting guided wave ultrasound in rails

NASA Astrophysics Data System (ADS)

Ramatlo, Dineo A.; Wilke, Daniel N.; Loveday, Philip W.

2017-02-01

An existing Ultrasonic Broken Rail Detection System installed in South Africa on a heavy duty railway line is currently being upgraded to include defect detection and location. To accomplish this, an ultrasonic piezoelectric transducer to strongly excite a guided wave mode with energy concentrated in the web (web mode) of a rail is required. A previous study demonstrated that the recently developed SAFE-3D (Semi-Analytical Finite Element - 3 Dimensional) method can effectively predict the guided waves excited by a resonant piezoelectric transducer. In this study, the SAFE-3D model is used in the design optimization of a rail web transducer. A bound-constrained optimization problem was formulated to maximize the energy transmitted by the transducer in the web mode when driven by a pre-defined excitation signal. Dimensions of the transducer components were selected as the three design variables. A Latin hypercube sampled design of experiments that required a total of 500 SAFE-3D analyses in the design space was employed in a response surface-based optimization approach. The Nelder-Mead optimization algorithm was then used to find an optimal transducer design on the constructed response surface. The radial basis function response surface was first verified by comparing a number of predicted responses against the computed SAFE-3D responses. The performance of the optimal transducer predicted by the optimization algorithm on the response surface was also verified to be sufficiently accurate using SAFE-3D. The computational advantages of SAFE-3D in optimal transducer design are noteworthy as more than 500 analyses were performed. The optimal design was then manufactured and experimental measurements were used to validate the predicted performance. The adopted design method has demonstrated the capability to automate the design of transducers for a particular rail cross-section and frequency range.
LX-04 VIOLENCE MEASUREMENTS- STEVEN TESTS IMPACTED BY PROJECTILES SHOT FROM A HOWITZER GUN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chidester, S K; Vandersall, K S; Switzer, L L

Characterization of the reaction violence of LX-04 explosive (85% HMX and 15% Viton A by weight) was obtained from Steven Impact Tests performed above the reaction initiation threshold. A 155 mm Howitzer propellant driven gas gun was used to accelerate the Steven Test projectiles in the range of approximately 170-300 m/s to react (ignite) the LX-04 explosive. Blast overpressure gauges, acoustic microphones, and high-speed photography characterized the level of high explosive reaction violence. A detonation in this velocity range was not observed and when comparing these results (and the Susan test results) with that of other HMX based explosives, LX-04more » has a more gradual reaction violence slope as the impact velocity increases. The high binder content (15%) of the LX-04 explosive is believed to be the key factor to the lower level of violence.« less
Exposure to seismic air gun signals causes physiological harm and alters behavior in the scallop Pecten fumatus

PubMed Central

McCauley, Robert D.; Fitzgibbon, Quinn P.; Hartmann, Klaas; Semmens, Jayson M.

2017-01-01

Seismic surveys map the seabed using intense, low-frequency sound signals that penetrate kilometers into the Earth’s crust. Little is known regarding how invertebrates, including economically and ecologically important bivalves, are affected by exposure to seismic signals. In a series of field-based experiments, we investigate the impact of exposure to seismic surveys on scallops, using measurements of physiological and behavioral parameters to determine whether exposure may cause mass mortality or result in other sublethal effects. Exposure to seismic signals was found to significantly increase mortality, particularly over a chronic (months postexposure) time scale, though not beyond naturally occurring rates of mortality. Exposure did not elicit energetically expensive behaviors, but scallops showed significant changes in behavioral patterns during exposure, through a reduction in classic behaviors and demonstration of a nonclassic “flinch” response to air gun signals. Furthermore, scallops showed persistent alterations in recessing reflex behavior following exposure, with the rate of recessing increasing with repeated exposure. Hemolymph (blood analog) physiology showed a compromised capacity for homeostasis and potential immunodeficiency, as a range of hemolymph biochemistry parameters were altered and the density of circulating hemocytes (blood cell analog) was significantly reduced, with effects observed over acute (hours to days) and chronic (months) scales. The size of the air gun had no effect, but repeated exposure intensified responses. We postulate that the observed impacts resulted from high seabed ground accelerations driven by the air gun signal. Given the scope of physiological disruption, we conclude that seismic exposure can harm scallops. PMID:28923925
A data fusion approach for track monitoring from multiple in-service trains

NASA Astrophysics Data System (ADS)

Lederman, George; Chen, Siheng; Garrett, James H.; Kovačević, Jelena; Noh, Hae Young; Bielak, Jacobo

2017-10-01

We present a data fusion approach for enabling data-driven rail-infrastructure monitoring from multiple in-service trains. A number of researchers have proposed using vibration data collected from in-service trains as a low-cost method to monitor track geometry. The majority of this work has focused on developing novel features to extract information about the tracks from data produced by individual sensors on individual trains. We extend this work by presenting a technique to combine extracted features from multiple passes over the tracks from multiple sensors aboard multiple vehicles. There are a number of challenges in combining multiple data sources, like different relative position coordinates depending on the location of the sensor within the train. Furthermore, as the number of sensors increases, the likelihood that some will malfunction also increases. We use a two-step approach that first minimizes position offset errors through data alignment, then fuses the data with a novel adaptive Kalman filter that weights data according to its estimated reliability. We show the efficacy of this approach both through simulations and on a data-set collected from two instrumented trains operating over a one-year period. Combining data from numerous in-service trains allows for more continuous and more reliable data-driven monitoring than analyzing data from any one train alone; as the number of instrumented trains increases, the proposed fusion approach could facilitate track monitoring of entire rail-networks.
A Physics Exploratory Experiment on Plasma Liner Formation

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Knapp, Charles E.; Kirkpatrick, Ronald C.; Siemon, Richard E.; Turchi, Peter

2002-01-01

Momentum flux for imploding a target plasma in magnetized target fusion (MTF) may be delivered by an array of plasma guns launching plasma jets that would merge to form an imploding plasma shell (liner). In this paper, we examine what would be a worthwhile experiment to do in order to explore the dynamics of merging plasma jets to form a plasma liner as a first step in establishing an experimental database for plasma-jets driven magnetized target fusion (PJETS-MTF). Using past experience in fusion energy research as a model, we envisage a four-phase program to advance the art of PJETS-MTF to fusion breakeven Q is approximately 1). The experiment (PLX (Plasma Liner Physics Exploratory Experiment)) described in this paper serves as Phase I of this four-phase program. The logic underlying the selection of the experimental parameters is presented. The experiment consists of using twelve plasma guns arranged in a circle, launching plasma jets towards the center of a vacuum chamber. The velocity of the plasma jets chosen is 200 km/s, and each jet is to carry a mass of 0.2 mg - 0.4 mg. A candidate plasma accelerator for launching these jets consists of a coaxial plasma gun of the Marshall type.
A Compact Torus Fusion Reactor Utilizing a Continuously Generated Strings of CT's. The CT String Reactor, CTSR.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hartman, C W; Reisman, D B; McLean, H S

2007-05-30

A fusion reactor is described in which a moving string of mutually repelling compact toruses (alternating helicity, unidirectional Btheta) is generated by repetitive injection using a magnetized coaxial gun driven by continuous gun current with alternating poloidal field. An injected CT relaxes to a minimum magnetic energy equilibrium, moves into a compression cone, and enters a conducting cylinder where the plasma is heated to fusion-producing temperature. The CT then passes into a blanketed region where fusion energy is produced and, on emergence from the fusion region, the CT undergoes controlled expansion in an exit cone where an alternating poloidal fieldmore » opens the flux surfaces to directly recover the CT magnetic energy as current which is returned to the formation gun. The CT String Reactor (CTSTR) reactor satisfies all the necessary MHD stability requirements and is based on extrapolation of experimentally achieved formation, stability, and plasma confinement. It is supported by extensive 2D, MHD calculations. CTSTR employs minimal external fields supplied by normal conductors, and can produce high fusion power density with uniform wall loading. The geometric simplicity of CTSTR acts to minimize initial and maintenance costs, including periodic replacement of the reactor first wall.« less
Self-bunching electron guns

NASA Astrophysics Data System (ADS)

Mako, Frederick M.; Len, L. K.

1999-05-01

We report on three electron gun projects that are aimed at power tube and injector applications. The purpose of the work is to develop robust electron guns which produce self-bunched, high-current-density beams. We have demonstrated, in a microwave cavity, self-bunching, cold electron emission, long life, and tolerance to contamination. The cold process is based on secondary electron emission. FMT has studied using simulation codes the resonant bunching process which gives rise to high current densities (0.01-5 kA/cm2), high charge bunches (up to 500 nC/bunch), and short pulses (1-100 ps) for frequencies from 1 to 12 GHz. The beam pulse width is nominally ˜5% of the rf period. The first project is the L-Band Micro-Pulse Gun (MPG). Measurements show ˜40 ps long micro-bunches at ˜20 A/cm2 without contamination due to air exposure. Lifetime testing has been carried out for about 18 months operating at 1.25 GHz for almost 24 hours per day at a repetition rate of 300 Hz and 5 μs-long macro-pulses. Approximately 5.8×1013 micro-bunches or 62,000 coulombs have passed through this gun and it is still working fine. The second project, the S-Band MPG, is now operational. It is functioning at a frequency of 2.85 GHz, a repetition rate of 30 Hz, with a 2 μs-long macro-pulse. It produces about 45 A in the macro-pulse. The third project is a 34.2 GHz frequency-multiplied source driven by an X-Band MPG. A point design was performed at an rf output power of 150 MW at 34.2 GHz. The resulting system efficiency is 53% and the gain is 60 dB. The system efficiency includes the input cavity efficiency, input driver efficiency (a 50 MW klystron at 11.4 GHz), output cavity efficiency, and the post-acceleration efficiency.
Repetitive switching for an electromagnetic rail gun

NASA Astrophysics Data System (ADS)

Gruden, J. M.

1983-12-01

Previous testing on a repetitive opening switch for inductive energy storage has proved the feasibility of the rotary switch concept. The concept consists of a rotating copper disk (rotor) with a pie-shaped insulator section and brushes which slide along each of the rotor surfaces. While on top of the copper surface, the brushes and rotor conduct current allowing the energy storage inductor to charge. When the brushes slide onto the insulator section, the current cannot pass through the rotor and is diverted into the load. This study investigates two new brush designs and a rotor modification designed to improve the current commutating capabilities of the switch. One brush design (fringe fiber) employs carbon fibers on the leading and trailing edge of the brush to increase the resistive commutating action as the switch opens and closes. The other brush design uses fingers to conduct current to the rotor surface, effectively increasing the number of brush contact points. The rotor modification was the placement of tungsten inserts at the copper-insulator interfaces.
Annual Summary Report on Thermionic Cathode Project.

DTIC Science & Technology

1986-01-09

Voltage Operation The electron gun cathode is driven negative by a high voltageRadiation pulse modulator in the circuit of Figure 3-1. Typical current...tungsten filament. The bombardment heating system is stabilized by a feed- back control circuit . The power required to heat tne cathode is 315 W bom...project. The primary purpose of the first phase was to develop the bombardment heating circuit used to heat the LaB 6 cathode, and to test the beam

Maximum current density and beam brightness achievable by laser-driven electron sources

NASA Astrophysics Data System (ADS)

Filippetto, D.; Musumeci, P.; Zolotorev, M.; Stupakov, G.

2014-02-01

This paper discusses the extension to different electron beam aspect ratio of the Child-Langmuir law for the maximum achievable current density in electron guns. Using a simple model, we derive quantitative formulas in good agreement with simulation codes. The new scaling laws for the peak current density of temporally long and transversely narrow initial beam distributions can be used to estimate the maximum beam brightness and suggest new paths for injector optimization.
Evaluation of Future Fuels in a High Pressure Common Rail System - Part 1 Cummins XPI

DTIC Science & Technology

2012-10-01

compressed against the underside of the pump head to maintain contact with the pump camshaft. The underside of the pump head is shown in Figure 5...Figure 5. High Pressure Pump Head Unclassified 8 The two barrel retainers located on the underside of the pump head hold the ceramic plungers...which develop the high pressures within the pump. The plungers are driven into the barrels by the tappets as the shaft turns. They are forced back out
Structural design of off-axis aspheric surface reflective zoom optical system

NASA Astrophysics Data System (ADS)

Zhang, Ke; Chang, Jun; Song, Haiping; Niu, Yajun

2018-01-01

Designed an off-axis aspheric reflective zoom optical system, and produced a prototype. The system consists of three aspheric reflective lens, the zoom range is 30mm { 90mm. This system gave up the traditional structure of zoom cam, the lens moved using linear guide rail driven by motor, the positioning precision of which was 0.01mm. And introduced the design of support frames of each lens. The practice tests verified the rationality of the prototype structure design.
Railguns

NASA Astrophysics Data System (ADS)

Marshall, R. A.

Descriptions are given of the following railgun systems: the fast-capacitor/inductor system, the slow-capacitor/inductance system, the homopolar generator/inductor system, the distributed energy store system, and the flux compressor powered railgun. Attention is also given to the inverse railgun flux compressor, where the piston is driven between the rails along which the inverted chevron armature slides. The development of the railgun since World War II is surveyed. It is noted that the most pressing need at present is for cheaper, simpler energy stores to couple to the railguns.
Highly Uniform Carbon Nanotube Field-Effect Transistors and Medium Scale Integrated Circuits.

PubMed

Chen, Bingyan; Zhang, Panpan; Ding, Li; Han, Jie; Qiu, Song; Li, Qingwen; Zhang, Zhiyong; Peng, Lian-Mao

2016-08-10

Top-gated p-type field-effect transistors (FETs) have been fabricated in batch based on carbon nanotube (CNT) network thin films prepared from CNT solution and present high yield and highly uniform performance with small threshold voltage distribution with standard deviation of 34 mV. According to the property of FETs, various logical and arithmetical gates, shifters, and d-latch circuits were designed and demonstrated with rail-to-rail output. In particular, a 4-bit adder consisting of 140 p-type CNT FETs was demonstrated with higher packing density and lower supply voltage than other published integrated circuits based on CNT films, which indicates that CNT based integrated circuits can reach to medium scale. In addition, a 2-bit multiplier has been realized for the first time. Benefitted from the high uniformity and suitable threshold voltage of CNT FETs, all of the fabricated circuits based on CNT FETs can be driven by a single voltage as small as 2 V.
Development of a two-stage light gas gun to accelerate hydrogen pellets to high speeds for plasma fueling applications

NASA Astrophysics Data System (ADS)

Combs, S. K.; Milora, S. L.; Foust, C. R.; Gouge, M. J.; Fehling, D. T.; Sparks, D. O.

1988-08-01

The development of a two-stage light gas gun to accelerate hydrogen isotope pellets to high speeds is under way at Oak Ridge National Laboratory. High velocities are desirable for plasma fueling applications, since the faster pellets can penetrate more deeply into large, hot plasmas and deposit atoms of fuel directly in a larger fraction of the plasma volume. In the initial configuration of the two-stage device, a 2.2-l volume provides the gas to accelerate a 25.4-mm-diam piston in a 1-m-long pump tube; a burst disk or a fast valve initiates the acceleration process in the first stage. As the piston travels the length of the pump tube, the downstream gas is compressed (to pressures up to 2600 bar) and thus is driven to high temperature (approx. 5000 K). This provides the driving force for acceleration of a 4-mm pellet in a 1-m-long gun barrel. In preliminary tests using helium as the driver in both stages, 35-mg plastic pellets have been accelerated to speeds as high as 3.8 km/s. Projectiles composed of hydrogen ice will have a mass in the range from 5 to 20 mg. However, the use of sabots to encase and protect the cryogenic pellets from the high peak pressures will probably be required to realize speeds of approx. 3 km/s or greater. The experimental plan includes acceleration of hydrogen isotopes as soon as the gun geometry and operating parameters are optimized; theoretical models are being used to aid in this process. The hardware is being designed to accommodate repetitive operation, which is the objective of this research and is required for future applications.
A fibre based triature interferometer for measuring rapidly evolving, ablatively driven plasma densities

NASA Astrophysics Data System (ADS)

Macdonald, J.; Bland, S. N.; Threadgold, J.

2015-08-01

We report on the first use of a fibre interferometer incorporating triature analysis for measuring rapidly evolving plasma densities of ne ˜ 1013/cm3 and above, such as those produced by simple coaxial plasma guns. The resultant system is extremely portable, easy to field in experiments, relatively cheap to produce, and—with the exception of a small open area in which the plasma is sampled—safe in operation as all laser light is enclosed.
Whose guns are stolen? The epidemiology of Gun theft victims.

PubMed

Hemenway, David; Azrael, Deborah; Miller, Matthew

2017-12-01

Gun theft is an important source of guns used by criminals. Yet no empirical work has focused on the characteristics of gun owners that distinguish those who have had their guns stolen from those who have not. In this study, we examine the demographics and behavioral characteristics of gun owners who report having had a gun stolen. Data come from a nationally representative probability-based online survey conducted in April 2015, with a linked follow-up survey in November 2015 that asked gun owners about any theft of their guns in the past 5 years. Of 1,604 gun-owning respondents, 2.4% (95% CI 1.6,3.6) reported that one or more guns had been stolen, with a mean number of guns stolen per theft of 1.5 (95% CI 1.0,2.0]. Risk factors for having a gun stolen were owning 6 or more guns, owning guns for protection, carrying a gun in the past month, storing guns unsafely, and living in the South region of the United States. The South accounts for 37% of US households, 43% of gun owners, and two-thirds of all gun thefts. We estimate that there are approximately 250,000 gun theft incidents per year, with about 380,000 guns stolen. We find that certain types of gun owners-who own many guns, who carry guns, and who do not store guns safely-are at higher risk to have their guns stolen. Tracing data show that states in the South are exporters of crime guns used in other states. Our survey results find that the majority of guns stolen in the US come from the South.
Threat perception after the Boston Marathon bombings: The effects of personal relevance and conceptual framing.

PubMed

Wormwood, Jolie Baumann; Lynn, Spencer K; Feldman Barrett, Lisa; Quigley, Karen S

2016-01-01

We examined how the Boston Marathon bombings affected threat perception in the Boston community. In a threat perception task, participants attempted to "shoot" armed targets and avoid shooting unarmed targets. Participants viewing images of the bombings accompanied by affectively negative music and text (e.g., "Terror Strikes Boston") made more false alarms (i.e., more errors "shooting" unarmed targets) compared to participants viewing the same images accompanied by affectively positive music and text (e.g., "Boston Strong") and participants who did not view bombing images. This difference appears to be driven by decreased sensitivity (i.e., decreased ability to distinguish guns from non-guns) as opposed to a more liberal bias (i.e., favouring the "shoot" response). Additionally, the more strongly affected the participant was by the bombings, the more their sensitivity was reduced in the negatively framed condition, suggesting that this framing was particularly detrimental to the most vulnerable individuals in the affected community.
Observation of a variable sub-THz radiation driven by a low energy electron beam from a thermionic rf electron gun

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smirnov, A. V.; Agustsson, R.; Berg, W. J.

We report observations of an intense sub-THz radiation extracted from a ~3 MeV electron beam with a flat transverse profile propagating between two parallel oversized copper gratings with side openings. Low-loss radiation outcoupling is accomplished using a horn antenna and a miniature permanent magnet separating sub-THz and electron beams. A tabletop experiment utilizes a radio frequency thermionic electron gun delivering a thousand momentum-chirped microbunches per macropulse and an alpha-magnet with a movable beam scraper producing sub-mm microbunches. The radiated energy of tens of micro-Joules per radio frequency macropulse is demonstrated. The frequency of the radiation peak was generated and tunedmore » across two frequency ranges: (476–584) GHz with 7% instantaneous spectrum bandwidth, and (311–334) GHz with 38% instantaneous bandwidth. In this study, the prototype setup features a robust compact source of variable frequency, narrow bandwidth sub-THz pulses.« less
Sound velocity of tantalum under shock compression in the 18–142 GPa range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xi, Feng, E-mail: xifeng@caep.cn; Jin, Ke; Cai, Lingcang, E-mail: cai-lingcang@aliyun.com

2015-05-14

Dynamic compression experiments of tantalum (Ta) within a shock pressure range from 18–142 GPa were conducted driven by explosive, a two-stage light gas gun, and a powder gun, respectively. The time-resolved Ta/LiF (lithium fluoride) interface velocity profiles were recorded with a displacement interferometer system for any reflector. Sound velocities of Ta were obtained from the peak state time duration measurements with the step-sample technique and the direct-reverse impact technique. The uncertainty of measured sound velocities were analyzed carefully, which suggests that the symmetrical impact method with step-samples is more accurate for sound velocity measurement, and the most important parameter in thismore » type experiment is the accurate sample/window particle velocity profile, especially the accurate peak state time duration. From these carefully analyzed sound velocity data, no evidence of a phase transition was found up to the shock melting pressure of Ta.« less
High precision Hugoniot measurements on statically pre-compressed fluid helium

NASA Astrophysics Data System (ADS)

Seagle, Christopher T.; Reinhart, William D.; Lopez, Andrew J.; Hickman, Randy J.; Thornhill, Tom F.

2016-09-01

The capability for statically pre-compressing fluid targets for Hugoniot measurements utilizing gas gun driven flyer plates has been developed. Pre-compression expands the capability for initial condition control, allowing access to thermodynamic states off the principal Hugoniot. Absolute Hugoniot measurements with an uncertainty less than 3% on density and pressure were obtained on statically pre-compressed fluid helium utilizing a two stage light gas gun. Helium is highly compressible; the locus of shock states resulting from dynamic loading of an initially compressed sample at room temperature is significantly denser than the cryogenic fluid Hugoniot even for relatively modest (0.27-0.38 GPa) initial pressures. The dynamic response of pre-compressed helium in the initial density range of 0.21-0.25 g/cm3 at ambient temperature may be described by a linear shock velocity (us) and particle velocity (up) relationship: us = C0 + sup, with C0 = 1.44 ± 0.14 km/s and s = 1.344 ± 0.025.
Concept definition study for an extremely large aerophysics range facility

NASA Technical Reports Server (NTRS)

Swift, Hallock F.

1993-01-01

A conceptual design of a very large aeroballistic range is presented, as are its operational characteristics and procedures. The proposed model launcher is a two-stage light-gas gun, having a launch tube diameter of 254 mm, and the capability of accelerating a 14 kg launch mass to 6.1 km/sec. The gun's 91.4 cm diameter piston is driven by pressurized helium. High pressures in the central breech are contained by a multiple disk arrangement. The blast tank and sabot separation tank are described, as are methods for arresting sabot segments. The conceptual design of the range itself includes a 3.3 m diameter test or flight chamber some 330 m in length. Provisions are made for testing of free flight models and tests in which the model is confined by a track system. Methods for model deceleration and recovery are described. Provisions required for future addition of advanced model launchers such as an electromagnetic launcher or ram accelerator are addressed. Siting and safety issues are also addressed.
Observation of a variable sub-THz radiation driven by a low energy electron beam from a thermionic rf electron gun

DOE PAGES

Smirnov, A. V.; Agustsson, R.; Berg, W. J.; ...

2015-09-29

We report observations of an intense sub-THz radiation extracted from a ~3 MeV electron beam with a flat transverse profile propagating between two parallel oversized copper gratings with side openings. Low-loss radiation outcoupling is accomplished using a horn antenna and a miniature permanent magnet separating sub-THz and electron beams. A tabletop experiment utilizes a radio frequency thermionic electron gun delivering a thousand momentum-chirped microbunches per macropulse and an alpha-magnet with a movable beam scraper producing sub-mm microbunches. The radiated energy of tens of micro-Joules per radio frequency macropulse is demonstrated. The frequency of the radiation peak was generated and tunedmore » across two frequency ranges: (476–584) GHz with 7% instantaneous spectrum bandwidth, and (311–334) GHz with 38% instantaneous bandwidth. In this study, the prototype setup features a robust compact source of variable frequency, narrow bandwidth sub-THz pulses.« less
Hypervelocity Impact Test Facility: A gun for hire

NASA Technical Reports Server (NTRS)

Johnson, Calvin R.; Rose, M. F.; Hill, D. C.; Best, S.; Chaloupka, T.; Crawford, G.; Crumpler, M.; Stephens, B.

1994-01-01

An affordable technique has been developed to duplicate the types of impacts observed on spacecraft, including the Shuttle, by use of a certified Hypervelocity Impact Facility (HIF) which propels particulates using capacitor driven electric gun techniques. The fully operational facility provides a flux of particles in the 10-100 micron diameter range with a velocity distribution covering the space debris and interplanetary dust particle environment. HIF measurements of particle size, composition, impact angle and velocity distribution indicate that such parameters can be controlled in a specified, tailored test designed for or by the user. Unique diagnostics enable researchers to fully describe the impact for evaluating the 'targets' under full power or load. Users regularly evaluate space hardware, including solar cells, coatings, and materials, exposing selected portions of space-qualified items to a wide range of impact events and environmental conditions. Benefits include corroboration of data obtained from impact events, flight simulation of designs, accelerated aging of systems, and development of manufacturing techniques.
Public Support for Gun Violence Prevention Policies Among Gun Owners and Non-Gun Owners in 2017.

PubMed

Barry, Colleen L; Webster, Daniel W; Stone, Elizabeth; Crifasi, Cassandra K; Vernick, Jon S; McGinty, Emma E

2018-07-01

To compare public support for 24 different gun policies between gun owners and non-gun owners in 2017. We fielded a national public opinion survey in January 2017 using an online panel to measure US adults' support for 24 gun policies. We compared support among gun owners and non-gun owners. For 23 of the 24 policies examined, most respondents supported restricting or regulating gun ownership. Only 8 of 24 policies had greater than a 10-point support gap between gun owners and non-gun owners. Policies with high public support and minimal support gaps by gun ownership status included universal background checks, greater accountability for licensed gun dealers unable to account for their inventory, higher safety training standards for concealed carry permit holders, improved reporting of records related to mental illness for background checks, gun prohibitions for persons subject to temporary domestic violence restraining orders, and gun violence restraining orders. Public Health Implications. Although there are important areas where Americans disagree on guns, large majorities of both gun owners and non-gun owners strongly support measures to strengthen US gun laws.
Recent breakthroughs on C-2U: Norman’s legacy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Binderbauer, M. W.; Tajima, T.; Tuszewski, M.

Conventional field-reversed configurations (FRC) face notable stability and confinement concerns, which can be ameliorated by introducing and maintaining a significant fast ion population in the system. This is the conjecture first introduced by Norman Rostoker multiple decades ago and adopted as the central design tenet in Tri Alpha Energy’s advanced beam driven FRC concept. In fact, studying the physics of such neutral beam (NB) driven FRCs over the past decade, considerable improvements were made in confinement and stability. Next to NB injection, the addition of axially streaming plasma guns, magnetic end plugs, as well as advanced surface conditioning lead tomore » dramatic reductions in turbulence driven losses and greatly improved stability. In turn, fast ion confinement improved significantly and allowed for the build-up of a dominant fast particle population. This recently led to the breakthrough of sustaining an advanced beam driven FRC, thereby demonstrating successful maintenance of trapped magnetic flux, plasma dimensions and total pressure inventory for times much longer than all characteristic system time scales and only limited by hardware and electric supply constraints.« less
Multiple pole electromagnetic propulsion system with separated ballistic guidance and electrical current contact surfaces

DOEpatents

Sims, Jr., James R.

2008-07-15

An electromagnetic propulsion system is disclosed having separate rails for ballistic guidance and for carrying current. In this system, one or more pairs of ballistic guidance rails are provided, with each ballistic guidance rail having a pair of current carrying rails joined to it to form a combined rail. Each combined rail is separated electrically from adjacent combined rails by electrically insulating blocks. Each of the current carrying rails in a given combined rail pair have the same electrical polarity, and the polarities alternate between adjacent combined rails. Armatures contact current carrying rails to complete the circuit to generate the accelerating Lorentz force on the armatures. Bore riders on the sabot and/or projectile are in contact with the ballistic guide rails. Separation of the current carrying and ballistic guidance functions increases resistance of the system to rail movement and bending, as well as reduced wear/damage to the rails. In further embodiments, a circumferential over wrap providing compressive force on the rails further increases resistance of the system to rail movement and bending.
State Gun Law Environment and Youth Gun Carrying in the United States.

PubMed

Xuan, Ziming; Hemenway, David

2015-11-01

Gun violence and injuries pose a substantial threat to children and youth in the United States. Existing evidence points to the need for interventions and policies for keeping guns out of the hands of children and youth. (1) To examine the association between state gun law environment and youth gun carrying in the United States, and (2) to determine whether adult gun ownership mediates this association. This was a repeated cross-sectional observational study design with 3 years of data on youth gun carrying from US states. The Youth Risk Behavior Survey comprises data of representative samples of students in grades 9 to 12 from biennial years of 2007, 2009, and 2011. We hypothesized that states with more restrictive gun laws have lower rates of youth gun carrying, and this association is mediated by adult gun ownership. State gun law environment as measured by state gun law score. Youth gun carrying was defined as having carried a gun on at least 1 day during the 30 days before the survey. In the fully adjusted model, a 10-point increase in the state gun law score, which represented a more restrictive gun law environment, was associated with a 9% decrease in the odds of youth gun carrying (adjusted odds ratio [AOR], 0.91 [95% CI, 0.86-0.96]). Adult gun ownership mediated the association between state gun law score and youth gun carrying (AOR, 0.94 [ 95% CI, 0.86-1.01], with 29% attenuation of the regression coefficient from -0.09 to -0.07 based on bootstrap resampling). More restrictive overall gun control policies are associated with a reduced likelihood of youth gun carrying. These findings are relevant to gun policy debates about the critical importance of strengthening overall gun law environment to prevent youth gun carrying.
Children and firearms in the home: a Southwestern Ohio Ambulatory Research Network (SOAR-Net) study.

PubMed

Forbis, Shalini G; McAllister, Terence R; Monk, Susan M; Schlorman, Christopher A; Stolfi, Adrienne; Pascoe, John M

2007-01-01

To ascertain the prevalence of gun ownership, gun safety education, and parental attitudes on gun counseling in a Midwestern sample. Parents seeking care at participating practices in the Southwestern Ohio Ambulatory Research Network were recruited to complete a survey about gun ownership, gun safety education, and gun counseling attitudes. Attitudes and beliefs were compared between gun owners and non-gun owners. Twenty-four percent of respondents had at least 1 gun in the home. Military families were more likely to own a gun than civilian families (28% vs 18%, P = .001). Fifty-two percent of sample children have received gun safety education. Eight percent indicated that a physician had asked about guns or discussed gun safety issues during an office visit. A majority of parents indicated that physicians should ask about guns in the home (69%) and advise parents on safe storage (75%), but they should not advise parents to remove guns from the home (12% of gun owners, 42% of non-gun owners). Despite the morbidity and mortality associated with guns, physicians in this study do not seem to be addressing this risk with families. A majority of gun owners do not agree that physicians should counsel the removal of guns from the home but agree that they should discuss safe gun storage information.

77 FR 17121 - RailAmerica, Inc., Palm Beach Rail Holding, Inc., RailAmerica Transportation Corp., RailTex, Inc...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-23

... Group, LLC, and RR Acquisition Holding, LLC--Control Exemption--Wellsboro & Corning Railroad, LLC Rail.... (RTC), RailTex, Inc. (RailTex), Fortress Investment Group, LLC (Fortress), and RR Acquisition Holding... acquire indirect control of the Wellsboro & Corning Railroad, LLC (W&C), a Class III rail carrier, through...
Lasers in space

NASA Astrophysics Data System (ADS)

Michaelis, M. M.; Forbes, A.; Bingham, R.; Kellett, B. J.; Mathye, A.

2008-05-01

A variety of laser applications in space, past, present, future and far future are reviewed together with the contributions of some of the scientists and engineers involved, especially those that happen to have South African connections. Historically, two of the earliest laser applications in space, were atmospheric LIDAR and lunar ranging. These applications involved atmospheric physicists, several astronauts and many of the staff recruited into the Soviet and North American lunar exploration programmes. There is a strong interest in South Africa in both LIDAR and lunar ranging. Shortly after the birth of the laser (and even just prior) theoretical work on photonic propulsion and space propulsion by laser ablation was initiated by Georgii Marx, Arthur Kantrowitz and Eugen Saenger. Present or near future experimental programs are developing in the following fields: laser ablation propulsion, possibly coupled with rail gun or gas gun propulsion; interplanetary laser transmission; laser altimetry; gravity wave detection by space based Michelson interferometry; the de-orbiting of space debris by high power lasers; atom laser interferometry in space. Far future applications of laser-photonic space-propulsion were also pioneered by Carl Sagan and Robert Forward. They envisaged means of putting Saenger's ideas into practice. Forward also invented a laser based method for manufacturing solid antimatter or SANTIM, well before the ongoing experiments at CERN with anti-hydrogen production and laser-trapping. SANTIM would be an ideal propellant for interstellar missions if it could be manufactured in sufficient quantities. It would be equally useful as a power source for the transmission of information over light year distances. We briefly mention military lasers. Last but not least, we address naturally occurring lasers in space and pose the question: "did the Big Bang lase?"
A compact and continuously driven supersonic plasma and neutral source.

PubMed

Asai, T; Itagaki, H; Numasawa, H; Terashima, Y; Hirano, Y; Hirose, A

2010-10-01

A compact and repetitively driven plasma source has been developed by utilizing a magnetized coaxial plasma gun (MCPG) for diagnostics requiring deep penetration of a large amount of neutral flux. The system consists of a MCPG 95mm in length with a DN16 ConFlat connection port and an insulated gate bipolar transistor (IGBT) inverter power unit. The power supply consists of an array of eight IGBT units and is able to switch the discharge on and off at up to 10 kV and 600 A with a maximum repetitive frequency of 10 kHz. Multiple short duration discharge pulses maximize acceleration efficiency of the plasmoid. In the case of a 10 kHz operating frequency, helium-plasmoids in the velocity range of 20 km/s can be achieved.
Impact of the rail-pad multi-discrete model upon the prediction of the rail response

NASA Astrophysics Data System (ADS)

Mazilu, T.; Leu, M.

2017-08-01

Wheel/rail vibration has many technical effects such as wear of the rolling surfaces, rolling noise, settlement of the ballast and subgrade etc. This vibration is depending on the rail pad characteristic and subsequently, it is important to have an accurate overview on the relation between the rail pad characteristic and the level of the wheel/rail vibration. To this end, much theoretical and experimental research has been developed in the past, and for the theoretical approach the track model, in general, and, particularly, the rail pad model is of crucial importance. Usually, the rail pad model is discrete model one, neglecting the length of the rail pad. This fact is questionable because the sleepers span is only 4 times the rail pad length. Using the rail pad discrete model, the rail response is overestimated when the frequency of the excitation equals the pinned-pinned resonance frequency. In this paper, a multi-discrete model for the rail pad, consisting in many Kelvin-Voigt parallel systems, is inserted into an analytical model of the track. The track model is reduced to a rail taken as infinite Timoshenko beam, discretely supported via rail pad, sleeper and ballast. The influence of the number of Kelvin-Voigt systems of the rail pad model on the rail response is analysed.
Structure and Properties of Thermite Welds in Premium Rails

DOT National Transportation Integrated Search

1985-12-01

Thermite welds were used to join combinations of premium rails and AREA Controlled Cooled Carbon rails (i.e., standard rails). The premium rails comprised head-hardened rails and CrMo, CrV and Cr alloy rails. A major objective was to determine the fe...
Design of an electron-accelerator-driven compact neutron source for non-destructive assay

NASA Astrophysics Data System (ADS)

Murata, A.; Ikeda, S.; Hayashizaki, N.

2017-09-01

The threat of nuclear and radiological terrorism remains one of the greatest challenges to international security, and the threat is constantly evolving. In order to prevent nuclear terrorism, it is important to avoid unlawful import of nuclear materials, such as uranium and plutonium. Development of technologies for non-destructive measurement, detection and recognition of nuclear materials is essential for control at national borders. At Tokyo Institute of Technology, a compact neutron source system driven by an electron-accelerator has been designed for non-destructive assay (NDA). This system is composed of a combination of an S-band (2.856 GHz) RF-gun, a tungsten target to produce photons by bremsstrahlung, a beryllium target, which is suitable for use in generating neutrons because of the low threshold energy of photonuclear reactions, and a moderator to thermalize the fast neutrons. The advantage of this system can accelerate a short pulse beam with a pulse width less than 1 μs which is difficult to produce by neutron generators. The amounts of photons and neutron produced by electron beams were simulated using the Monte Carlo simulation code PHITS 2.82. When the RF-gun is operated with an average electron beam current of 0.1 mA, it is expected that the neutron intensities are 1.19 × 109 n/s and 9.94 × 109 n/s for incident electron beam energies of 5 MeV and 10 MeV, respectively.
Gun Shows and Gun Violence: Fatally Flawed Study Yields Misleading Results

PubMed Central

Hemenway, David; Webster, Daniel; Pierce, Glenn; Braga, Anthony A.

2010-01-01

A widely publicized but unpublished study of the relationship between gun shows and gun violence is being cited in debates about the regulation of gun shows and gun commerce. We believe the study is fatally flawed. A working paper entitled “The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas” outlined this study, which found no association between gun shows and gun-related deaths. We believe the study reflects a limited understanding of gun shows and gun markets and is not statistically powered to detect even an implausibly large effect of gun shows on gun violence. In addition, the research contains serious ascertainment and classification errors, produces results that are sensitive to minor specification changes in key variables and in some cases have no face validity, and is contradicted by 1 of its own authors’ prior research. The study should not be used as evidence in formulating gun policy. PMID:20724672
Gun shows and gun violence: fatally flawed study yields misleading results.

PubMed

Wintemute, Garen J; Hemenway, David; Webster, Daniel; Pierce, Glenn; Braga, Anthony A

2010-10-01

A widely publicized but unpublished study of the relationship between gun shows and gun violence is being cited in debates about the regulation of gun shows and gun commerce. We believe the study is fatally flawed. A working paper entitled "The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas" outlined this study, which found no association between gun shows and gun-related deaths. We believe the study reflects a limited understanding of gun shows and gun markets and is not statistically powered to detect even an implausibly large effect of gun shows on gun violence. In addition, the research contains serious ascertainment and classification errors, produces results that are sensitive to minor specification changes in key variables and in some cases have no face validity, and is contradicted by 1 of its own authors' prior research. The study should not be used as evidence in formulating gun policy.
Dynamics of Plasma Jets and Bubbles Launched into a Transverse Background Magnetic Field

NASA Astrophysics Data System (ADS)

Zhang, Yue

2017-10-01

A coaxial magnetized plasma gun has been utilized to launch both plasma jets (open B-field) and plasma bubbles (closed B-field) into a transverse background magnetic field in the HelCat (Helicon-Cathode) linear device at the University of New Mexico. These situations may have bearing on fusion plasmas (e.g. plasma injection for tokamak fueling, ELM pacing, or disruption mitigation) and astrophysical settings (e.g. astrophysical jet stability, coronal mass ejections, etc.). The magnetic Reynolds number of the gun plasma is 100 , so that magnetic advection dominates over magnetic diffusion. The gun plasma ram pressure, ρjetVjet2 >B02 / 2μ0 , the background magnetic pressure, so that the jet or bubble can easily penetrate the background B-field, B0. When the gun axial B-field is weak compared to the gun azimuthal field, a current-driven jet is formed with a global helical magnetic configuration. Applying the transverse background magnetic field, it is observed that the n = 1 kink mode is stabilized, while magnetic probe measurements show contrarily that the safety factor q(a) drops below unity. At the same time, a sheared axial jet velocity is measured. We conclude that the tension force arising from increasing curvature of the background magnetic field induces the measured sheared flow gradient above the theoretical kink-stabilization threshold, resulting in the emergent kink stabilization of the injected plasma jet. In the case of injected bubbles, spheromak-like plasma formation is verified. However, when the spheromak plasma propagates into the transverse background magnetic field, the typical self-closed global symmetry magnetic configuration does not hold any more. In the region where the bubble toroidal field opposed the background B-field, the magneto-Rayleigh-Taylor (MRT) instability has been observed. Details of the experiment setup, diagnostics, experimental results and theoretical analysis will be presented. Supported by the National Science Foundation under Grant No. AST-0613577 and the Army Research Office under Award No. W911NF1510480. This work performed in collaboration with D. Fisher, A. G. Lynn, M Gilmore, and S. C. Hsu.
76 FR 55335 - Alternate Passenger Rail Service Pilot Program

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-07

... proceeding to develop a pilot program that permits a rail carrier or rail carriers that own infrastructure... develop a pilot program that permits a rail carrier or rail carriers that own infrastructure over which... that permits a rail carrier or rail carriers that own infrastructure over which Amtrak operates a...
77 FR 12107 - RailAmerica, Inc., Palm Beach Holding, Inc., RailAmerica Transportation Corp., RailTex, Inc...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-28

...., Palm Beach Holding, Inc., RailAmerica Transportation Corp., RailTex, Inc., Fortress Investment Group, LLC, and RR Acquisition Holding, LLC--Control Exemption--Marquette Rail, LLC AGENCY: Surface...), RailTex, Inc., Fortress Investment Group, LLC (Fortress), and RR Acquisition Holding, LLC (RR...
75 FR 76520 - Tennessee Southern Railroad Company, Patriot Rail, LLC, Patriot Rail Holdings LLC, and Patriot...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-08

... family by converting two of its subsidiaries from corporations into limited liability companies: (1... Railroad Company, Patriot Rail, LLC, Patriot Rail Holdings LLC, and Patriot Rail Corp.--Corporate Family... Railroad Company (TSRR), Patriot Rail, LLC (PRL) and its subsidiaries, Patriot Rail Holdings LLC (PRH) and...
Renaissance of the Web

NASA Astrophysics Data System (ADS)

McCarty, M.

2009-09-01

The renaissance of the web has driven development of many new technologies that have forever changed the way we write software. The resulting tools have been applied to both solve problems and creat new ones in a wide range of domains ranging from monitor and control user interfaces to information distribution. This discussion covers which of and how these technologies are being used in the astronomical computing community. Topics include JavaScript, Cascading Style Sheets, HTML, XML, JSON, RSS, iCalendar, Java, PHP, Python, Ruby on Rails, database technologies, and web frameworks/design patterns.
High-repetition-rate short-pulse gas discharge.

PubMed

Tulip, J; Seguin, H; Mace, P N

1979-09-01

A high-average-power short-pulse gas discharge is described. This consists of a volume-preionized transverse discharge of the type used in gas lasers driven by a Blumlein energy storage circuit. The Blumlein circuit is fabricated from coaxial cable, is pulse-charged from a high-repetition-rate Marx-bank generator, and is switched by a high-repetition-rate segmented rail gap. The operation of this discharge under conditions typical of rare-gas halide lasers is described. A maximum of 900 pps was obtained, giving a power flow into the discharge of 30 kW.
Fast rail corrugation detection based on texture filtering

NASA Astrophysics Data System (ADS)

Xiao, Jie; Lu, Kaixia

2018-02-01

The condition detection of rails in high-speed railway is one of the important means to ensure the safety of railway transportation. In order to replace the traditional manual inspection, save manpower and material resources, and improve the detection speed and accuracy, it is of great significance to develop a machine vision system for locating and identifying defects on rails automatically. Rail defects exhibit different properties and are divided into various categories related to the type and position of flaws on the rail. Several kinds of interrelated factors cause rail defects such as type of rail, construction conditions, and speed and/or frequency of trains using the rail. Rail corrugation is a particular kind of defects that produce an undulatory deformation on the rail heads. In high speed train, the corrugation induces harmful vibrations on wheels and its components and reduces the lifetime of rails. This type of defects should be detected to avoid rail fractures. In this paper, a novel method for fast rail corrugation detection based on texture filtering was proposed.
Securing America’s Passenger-Rail Systems

DTIC Science & Technology

2007-01-01

around the world highlight the vulnerability of rail travel and the importance of rail security for these passengers. The use of passenger rail and...take to U.S. railways. Recent attacks on passenger-rail systems around the world highlight the vulnerability of rail travel and the importance of rail...rails (Boardman, 2005), making more than 3.5 billion trips (APTA, 2006).1 And these estimates do not count the passengers traveling on the National
Green's functions for analysis of dynamic response of wheel/rail to vertical excitation

NASA Astrophysics Data System (ADS)

Mazilu, Traian

2007-09-01

An analytical model to simulate wheel/rail interaction using the Green's functions method is proposed in this paper. The model consists of a moving wheel on a discretely supported rail. Particularly for this model of rail, the bending and the longitudinal displacement are coupled due to the rail pad and a complex model of the rail pad is adopted. An efficient method for solving a time-domain analysis for wheel/rail interaction is presented. The method is based on the properties of the rail's Green functions and starting to these functions, a track's Green matrix is assembled for the numerical simulations of wheel/rail response due to three kinds of vertical excitations: the steady-state interaction, the rail corrugation and the wheel flat. The study points to influence of the worn rail—rigid contact—on variation in the wheel/rail contact force. The concept of pinned-pinned inhibitive rail pad is also presented.
Gun ownership and social gun culture

PubMed Central

Kalesan, Bindu; Villarreal, Marcos D; Keyes, Katherine M; Galea, Sandro

2016-01-01

We assessed gun ownership rates in 2013 across the USA and the association between exposure to a social gun culture and gun ownership. We used data from a nationally representative sample of 4000 US adults, from 50 states and District of Columbia, aged >18 years to assess gun ownership and social gun culture performed in October 2013. State-level firearm policy information was obtained from the Brady Law Center and Injury Prevention and Control Center. One-third of Americans reported owning a gun, ranging from 5.2% in Delaware to 61.7% in Alaska. Gun ownership was 2.25-times greater among those reporting social gun culture (PR=2.25, 95% CI 2.02 to 2.52) than those who did not. In conclusion, we found strong association between social gun culture and gun ownership. Gun cultures may need to be considered for public health strategies that aim to change gun ownership in the USA. PMID:26124073
Temporal association between federal gun laws and the diversion of guns to criminals in Milwaukee.

PubMed

Webster, Daniel W; Vernick, Jon S; Bulzacchelli, Maria T; Vittes, Katherine A

2012-02-01

The practices of licensed gun dealers can threaten the safety of urban residents by facilitating the diversion of guns to criminals. In 2003, changes to federal law shielded gun dealers from the release of gun trace data and provided other protections to gun dealers. The 14-month period during which the dealer did not sell junk guns was associated with a 68% reduction in the diversion of guns to criminals within a year of sale by the dealer and a 43% increase in guns diverted to criminals following sales by other dealers. The laws were associated with a 203% increase in the number of guns diverted to criminals within a year of sale by the gun store, which was the focus of this study. Policies which affect gun dealer accountability appeared to influence the diversion of guns to criminals.
Water gun vs air gun: A comparison

USGS Publications Warehouse

Hutchinson, D.R.; Detrick, R. S.

1984-01-01

The water gun is a relatively new marine seismic sound source that produces an acoustic signal by an implosive rather than explosive mechanism. A comparison of the source characteristics of two different-sized water guns with those of conventional air guns shows the the water gun signature is cleaner and much shorter than that of a comparable-sized air gun: about 60-100 milliseconds (ms) for an 80-in3. (1.31-liter (I)) water gun compared with several hundred ms for an 80-in3. (1.31-1) air gun. The source spectra of water guns are richer in high frequencies (>200 Hz) than are those of air guns, but they also have less energy than those of air guns at low frequencies. A comparison between water gun and air gun reflection profiles in both shallow (Long Island Sound)-and deep (western Bermuda Rise)-water settings suggests that the water gun offers a good compromise between very high resolution, limited penetration systems (e.g. 3.5-kHz profilers and sparkers) and the large volume air guns and tuned air gun arrays generally used where significant penetration is required. ?? 1984 D. Reidel Publishing Company.

Lunar launch and landing facilities and operations

NASA Technical Reports Server (NTRS)

1987-01-01

The Florida Institute of Technology established an Interdisciplinary Design Team to design a lunar based facility whose primary function involves launch and landing operations for future moon missions. Both manned and unmanned flight operations were considered in the study with particular design emphasis on the utilization (or reutilization) of all materials available on the moon. This resource availability includes man-made materials which might arrive in the form of expendable landing vehicles as well as in situ lunar minerals. From an engineering standpoint, all such materials are considered as to their suitability for constructing new lunar facilities and/or repairing or expanding existing structures. Also considered in this design study was a determination of the feasibility of using naturally occurring lunar materials to provide fuel components to support lunar launch operations. Conventional launch and landing operations similar to those used during the Apollo Program were investigated as well as less conventional techniques such as rail guns and electromagnetic mass drivers. The Advanced Space Design team consisted of students majoring in Physics and Space Science as well as Electrical, Mechanical, Chemical and Ocean Engineering.
Differences Between New and Long-Standing US Gun Owners: Results From a National Survey.

PubMed

Wertz, Joseph; Azrael, Deborah; Hemenway, David; Sorenson, Susan; Miller, Matthew

2018-07-01

To quantify the proportion of current US gun owners who are new to owning firearms and compare new versus long-standing gun owners with respect to their firearms and firearm-related behaviors. We performed a cross-sectional analysis of a nationally representative probability-based online survey conducted in 2015 in the United States. We defined new gun owners as current firearm owners who acquired all of their firearms within the past 5 years, but who lived in a home without a gun at some time over the past 5 years. We defined long-standing firearm owners as all other current gun owners. New gun owners represented 10% of all current US adult gun owners. In addition to being younger than long-standing gun owners, new gun owners were more likely to be liberal, own fewer guns, own handguns, own guns only for protection, and store guns in a safe manner. Gun ownership is dynamic, with approximately 1 million Americans becoming new gun owners each year. Public Health Implications. Clinical guidelines should be updated to explicitly endorse re-evaluating household firearm status at regular intervals.
Investigation on CWR longitudinal restraint behavior in winter rail break and summer destressing operations.

DOT National Transportation Integrated Search

1997-08-01

This report presents the results of investigations on the rail anchor/fastener effects on rail movement and the resulting rail force distribution in continuous welded rail (CWR) track during rail breaks and destressing operations. Two types of tests ...
78 FR 65244 - Rail Vehicles Access Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-31

...-0001] RIN 3014-AA42 Rail Vehicles Access Advisory Committee AGENCY: Architectural and Transportation Barriers Compliance Board. ACTION: Notice of advisory committee meeting. SUMMARY: The Rail Vehicles Access... vehicles that operate on fixed guideway systems (e.g., rapid rail, light rail, commuter rail, intercity...
49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of a...
49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of a...
49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of a...
49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of a...
49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of a...
A Piloted Simulation Investigating Handling Qualities and Performance Requirements of a Single-Pilot Helicopter in Air Combat Employing a Helmet-Driven Turreted Gun.

DTIC Science & Technology

1987-09-01

Jeffrey N. Williams September 1987 Thesis Advisor Donald M. Layton Approved for public release; distribution is unlimited. 7 14 44 r uaKjjW...I . - TBLE 9 PARTICIPATING EVALUATION PILOTS CW 2 John Burt, US. Army MAI Eric L Mitchell, U.S. Army ACM Instructor Pilot, Utah ANG Test Pilot...M. Layton , Code 67Ln I Department of Aeronautics Naval Postgraduate School Monterey, CA 93943 5. Dr. J. Victor Lebacqz 6 Chief, Flight Dynamics and
77 FR 37834 - Revocation of Certain Requirements Pertaining to Caps Intended for Use With Toy Guns and Toy Guns...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-25

... Certain Requirements Pertaining to Caps Intended for Use With Toy Guns and Toy Guns Not Intended for Use... compliance than our existing regulations pertaining to caps intended for use with toy guns and toy guns not... regulations pertaining to caps intended for use with toy guns and toy guns not intended for use with caps...
Real-time and accurate rail wear measurement method and experimental analysis.

PubMed

Liu, Zhen; Li, Fengjiao; Huang, Bangkui; Zhang, Guangjun

2014-08-01

When a train is running on uneven or curved rails, it generates violent vibrations on the rails. As a result, the light plane of the single-line structured light vision sensor is not vertical, causing errors in rail wear measurements (referred to as vibration errors in this paper). To avoid vibration errors, a novel rail wear measurement method is introduced in this paper, which involves three main steps. First, a multi-line structured light vision sensor (which has at least two linear laser projectors) projects a stripe-shaped light onto the inside of the rail. Second, the central points of the light stripes in the image are extracted quickly, and the three-dimensional profile of the rail is obtained based on the mathematical model of the structured light vision sensor. Then, the obtained rail profile is transformed from the measurement coordinate frame (MCF) to the standard rail coordinate frame (RCF) by taking the three-dimensional profile of the measured rail waist as the datum. Finally, rail wear constraint points are adopted to simplify the location of the rail wear points, and the profile composed of the rail wear points are compared with the standard rail profile in RCF to determine the rail wear. Both real data experiments and simulation experiments show that the vibration errors can be eliminated when the proposed method is used.
Gun Safety (For Kids)

MedlinePlus

... Staying Safe Videos for Educators Search English Español Gun Safety KidsHealth / For Kids / Gun Safety What's in ... from guns outside the home. If You Have Guns in Your Home If your parents keep guns ...
Gun threats against and self-defense gun use by California adolescents.

PubMed

Hemenway, David; Miller, Matthew

2004-04-01

To assess hostile gun use against and self-defense gun use by adolescents. We use random-digit-dial telephone survey data collected from approximately 5800 California adolescents, aged 12 through 17 years, between November 1, 2000, and October 31, 2001. The prevalence and correlates of reported hostile gun use against and self-defense gun use by adolescents, as well as qualitative information about these 2 types of gun uses. Correlates include age, sex, ethnicity, smoking, alcoholic binge drinking, threatening others, parents knowing their adolescent's whereabouts in the afternoon after school, attending school, area urbanization and poverty level, and living in a household with a gun. Approximately 4% of the adolescents reported ever having been threatened with a gun; only 0.3% reported using a gun in self-defense. Boys, smokers, adolescents who threatened others, and adolescents whose parents knew little about their whereabouts in the afternoon after school were more likely to report being threatened with a gun. Most episodes of self-defense gun use seem to be hostile interactions between adolescents with weapons. Far more California adolescents are threatened with a gun than use a gun in self-defense. Self-defense gun use is rare; many of the reported self-defense gun uses seem to be armed confrontations.
Asymmetric Brownian motor driven by bubble formation in a hydrophobic channel.

PubMed

Arai, Noriyoshi; Yasuoka, Kenji; Koishi, Takahiro; Ebisuzaki, Toshikazu

2010-10-26

The "asymmetric brownian ratchet model" is a variation of Feynman's ratchet and pawl system proposed. In this model, a system consisting of a motor and a rail has two binding states. One is the random brownian state, and the other is the asymmetric potential state. When the system is alternatively switched between these states, the motor can be driven in one direction. This model is believed to explain nanomotor behavior in biological systems. The feasibility of the model has been demonstrated using electrical and magnetic forces; however, switching of these forces is unlikely to be found in biological systems. In this paper, we propose an original mechanism of transition between states by bubble formation in a nanosized channel surrounded by hydrophobic atoms. This amounts to a nanoscale motor system using bubble propulsion. The motor system consists of a hydrophobic motor and a rail on which hydrophobic patterns are printed. Potential asymmetry can be produced by using a left-right asymmetric pattern shape. Hydrophobic interactions are believed to play an important role in the binding of biomolecules and molecular recognition. The bubble formation is controlled by changing the width of the channel by an atomic distance (∼0.1 nm). Therefore, the motor is potentially more efficient than systems controlled by other forces, in which a much larger change in the motor position is necessary. We have simulated the bubble-powered motor using dissipative particle dynamics and found behavior in good agreement with that of motor proteins. Energy efficiency is as high as 60%.
Guns and Violence. Current Controversies.

ERIC Educational Resources Information Center

Kim, Henny H., Ed.

This book focuses on gun violence and gun control, presenting both sides of arguments about firearms ownership and gun control. Each of five chapters poses a question about gun control and provides answers for both sides of the question. The following essays are included: (1) "Gun Violence Is Becoming an Epidemic" (Bob Herbert); (2) "Gun Violence…
Gun Control, Gun Ownership, and Suicide Prevention.

ERIC Educational Resources Information Center

Lester, David

1988-01-01

Explored relationship between the extent of gun ownership and the strictness of gun control laws to suicide and homicide rates in the nine major geographic regions of the United States. Found gun ownership, rather than the strictness of gun control laws, was the strongest correlate of the rates of suicide and homicide by guns. (Author)
Gun ownership and social gun culture.

PubMed

Kalesan, Bindu; Villarreal, Marcos D; Keyes, Katherine M; Galea, Sandro

2016-06-01

We assessed gun ownership rates in 2013 across the USA and the association between exposure to a social gun culture and gun ownership. We used data from a nationally representative sample of 4000 US adults, from 50 states and District of Columbia, aged >18 years to assess gun ownership and social gun culture performed in October 2013. State-level firearm policy information was obtained from the Brady Law Center and Injury Prevention and Control Center. One-third of Americans reported owning a gun, ranging from 5.2% in Delaware to 61.7% in Alaska. Gun ownership was 2.25-times greater among those reporting social gun culture (PR=2.25, 95% CI 2.02 to 2.52) than those who did not. In conclusion, we found strong association between social gun culture and gun ownership. Gun cultures may need to be considered for public health strategies that aim to change gun ownership in the USA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
40 CFR 201.13 - Standard for rail car operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Standard for rail car operations. 201... Interstate Rail Carrier Operations Standards § 201.13 Standard for rail car operations. Effective December 31, 1976, no carrier subject to this regulation shall operate any rail car or combination of rail cars...
40 CFR 201.13 - Standard for rail car operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Standard for rail car operations. 201... Interstate Rail Carrier Operations Standards § 201.13 Standard for rail car operations. Effective December 31, 1976, no carrier subject to this regulation shall operate any rail car or combination of rail cars...

40 CFR 201.13 - Standard for rail car operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Standard for rail car operations. 201... Interstate Rail Carrier Operations Standards § 201.13 Standard for rail car operations. Effective December 31, 1976, no carrier subject to this regulation shall operate any rail car or combination of rail cars...
40 CFR 201.13 - Standard for rail car operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Standard for rail car operations. 201... Interstate Rail Carrier Operations Standards § 201.13 Standard for rail car operations. Effective December 31, 1976, no carrier subject to this regulation shall operate any rail car or combination of rail cars...
40 CFR 201.13 - Standard for rail car operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Standard for rail car operations. 201... Interstate Rail Carrier Operations Standards § 201.13 Standard for rail car operations. Effective December 31, 1976, no carrier subject to this regulation shall operate any rail car or combination of rail cars...
78 FR 32007 - Environmental Impact Statement for Tulsa-Oklahoma City Passenger Rail Corridor, Oklahoma, Lincoln...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-28

... Environmental Policy Act of 1969 (NEPA) for the State of Oklahoma High-Speed Rail Initiative: Tulsa--Oklahoma... South Central High Speed Rail Corridor and is a federally-designated high-speed rail (HSR) corridor...-Speed Rail Initiative: Tulsa--Oklahoma City Passenger Rail Corridor Investment Plan. The proposed route...
Solar panel truss mounting systems and methods

DOEpatents

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2015-10-20

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.
Solar panel truss mounting systems and methods

DOEpatents

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2016-06-28

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.
Water guns affect abundance and behavior of bigheaded carp and native fish differently

USGS Publications Warehouse

Rivera, Jose; Glover, David C.; Kocovsky, Patrick; Garvey, James E.; Gaikowski, Mark; Jensen, Nathan R.; Adams, Ryan F.

2018-01-01

Water guns have shown the potential to repel nuisance aquatic organisms. This study examines the effects of exposure to a 1966.4 cm3 seismic water gun array (two guns) on the abundance and behavior of Bighead Carp Hypophthalmichthys nobilis, Silver Carp H. molitrix (collectively referred to as bigheaded carp) and native fishes (e.g., Smallmouth Buffalo Ictiobus bubalus). Water guns were deployed in a channel that connects the Illinois River to backwater quarry pits that contained a large transient population of bigheaded carp. To evaluate the effect of water guns, mobile side-looking split-beam hydroacoustic surveys were conducted before, during and between replicated water gun firing periods. Water guns did not affect abundance of bigheaded carp, but abundance of native fish detected during the firing treatment was 43 and 34% lower than the control and water guns off treatments, respectively. The proximity of bigheaded carp to the water gun array was similar between the water guns on and water guns off treatments. In contrast, the closest detected native fish were detected farther from the water guns during the water guns on treatment (mean ± SE, 32.38 ± 3.32 m) than during the water guns off treatment (15.04 ± 1.59 m). The water gun array had a greater impact on native fish species than on bigheaded carp. Caution should be taken to the extrapolation of these results to other fish species and to fish exposed to water guns in different environments (e.g., reduced shoreline interaction) or exposure to a larger array of water guns, or for use of water guns for purposes other than a barrier.
Review on Selection and Suitability of Rail Transit Station Design Pertaining to Public Safety

NASA Astrophysics Data System (ADS)

Akabal, Farah Mohd; Masirin, Mohd Idrus Haji Mohd; Abidin Akasah, Zainal; Rohani, Munzilah Md

2017-08-01

Railway has emerged as a fast, convenient, safe, clean, and low-cost alternative to air and road transportation. Many countries have invested in rail transportation. In America, Europe and Asia, large investments are planned for rail transportation. This is because congestion problems can be reduced with the introduction of rail transportation. Rail transportation involves several components which are important to ensure the smooth and safe delivery of services such as locomotives, rail stations and railway tracks. Rail transit stations are places where trains stop to pick-up and drop-off passengers. Stations are vital for many to enable them to engage in work and social commitments. This paper focuses only on the rail transit station as it is one of the important components in rail transportation. It is also considered as a key public meeting place and space for interactions in a community. The role of rail transit station and the requirements of a good rail transit station are also described in this paper. Steps in selecting the location of rail transit station include the function and facilities in rail transit station are discussed with reference to best practices and handbooks. Selection of the appropriate rail transit station locations may help users indirectly. In addition, this paper will also elucidate on the design considerations for an efficient and effective rail transit station. Design selections for the rail transit station must be balanced between aesthetic value and functional efficiency. The right design selection may help conserve energy, assure and facilitate consumers even thought a rail transit station plays a smaller role in attracting consumers compared to a shopping complex or a residential building. This will contribute towards better and greener building for a green transportation facility. Thus, with this paper it is expected to assist the relevant authority to identify important elements in the selection and determination of suitable rail transit station design for the future. It is also important to ensure the design is appropriate from the selection and suitability perspective as design and operation will assist to facilitate the success of the national rail network and encourage the public to use rail transit system. A conducive and neatly design railway station will not only add to the passenger experience but also, as a supporting facility to the economic, social and environmental benefits of the rail industry.
Modern Methods of Rail Welding

NASA Astrophysics Data System (ADS)

Kozyrev, Nikolay A.; Kozyreva, Olga A.; Usoltsev, Aleksander A.; Kryukov, Roman E.; Shevchenko, Roman A.

2017-10-01

Existing methods of rail welding, which are enable to get continuous welded rail track, are observed in this article. Analysis of existing welding methods allows considering an issue of continuous rail track in detail. Metallurgical and welding technologies of rail welding and also process technologies reducing aftereffects of temperature exposure are important factors determining the quality and reliability of the continuous rail track. Analysis of the existing methods of rail welding enable to find the research line for solving this problem.
Where the guns come from: the gun industry and gun commerce.

PubMed

Wintemute, Garen J

2002-01-01

Under federal law, it is illegal for youth under age 18 to purchase rifles or shotguns, and for those under age 21 to purchase handguns. However, fatality and injury statistics clearly show that guns are finding their way into young people's hands. Many of these youth obtain guns through illegal gun markets. This article focuses on how guns in the United States are manufactured, marketed, and sold. The article shows how the legal and illegal gun markets are intimately connected and make guns easily accessible to youth. Although the domestic gun manufacturing industry is relatively small and has experienced declining sales in recent years, it has significant political clout and a large market for its products, and has engaged in aggressive marketing to youth. Lax oversight of licensed firearms dealers, combined with little or no regulation of private sales between gun owners, mean that guns can quickly moved from the legal gun market into the illegal market, where they can be acquired by young people. Certain guns, especially inexpensive, poorly made small handguns, are particularly attractive to criminals and youth. The author observes that several policy innovations--including increased regulation of licensed firearms dealers, intensified screening of prospective buyers, regulation of private sales, gun licensing and registration, and bans on some types of weapons--hold promise for decreasing the flow of guns into the hands of youth.
Gas gun driven dynamic fracture and fragmentation of Ti-6Al-4V cylinders

NASA Astrophysics Data System (ADS)

Jones, D. R.; Chapman, D. J.; Eakins, D. E.

2014-05-01

The dynamic fracture and fragmentation of a material is a complex late stage phenomenon occurring in many shock loading scenarios. Improving our predictive capability depends upon exercising our current failure models against new loading schemes and data. We present axially-symmetric high strain rate (104 s-1) expansion of Ti-6Al-4V cylinders using a single stage light gas gun technique. A steel ogive insert was located inside the target cylinder, into which a polycarbonate rod was launched. Deformation of this rod around the insert drives the cylinder into rapid expansion. This technique we have developed facilitates repeatable loading, independent of the temperature of the sample cylinder, with straightforward adjustment of the radial strain rate. Expansion velocity was measured with multiple channels of photon Doppler velocimetry. High speed imaging was used to track the overall expansion process and record strain to failure and crack growth. Results from a cylinder at a temperature of 150 K are compared with work at room temperature, examining the deformation, failure mechanisms and differences in fragmentation.
High precision Hugoniot measurements on statically pre-compressed fluid helium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seagle, Christopher T.; Reinhart, William D.; Lopez, Andrew J.

Here we describe how the capability for statically pre-compressing fluid targets for Hugoniot measurements utilizing gas gun driven flyer plates has been developed. Pre-compression expands the capability for initial condition control, allowing access to thermodynamic states off the principal Hugoniot. Absolute Hugoniot measurements with an uncertainty less than 3% on density and pressure were obtained on statically pre-compressed fluid helium utilizing a two stage light gas gun. Helium is highly compressible; the locus of shock states resulting from dynamic loading of an initially compressed sample at room temperature is significantly denser than the cryogenic fluid Hugoniot even for relatively modestmore » (0.27–0.38 GPa) initial pressures. Lastly, the dynamic response of pre-compressed helium in the initial density range of 0.21–0.25 g/cm3 at ambient temperature may be described by a linear shock velocity (us) and particle velocity (u p) relationship: u s = C 0 + su p, with C 0 = 1.44 ± 0.14 km/s and s = 1.344 ± 0.025.« less
Experimental investigation of nozzle/plume aerodynamics at hypersonic speeds

NASA Technical Reports Server (NTRS)

Bogdanoff, David W.; Cambier, Jean-Luc; Papadopoulos, Perikles

1994-01-01

Much of the work involved the Ames 16-Inch Shock Tunnel facility. The facility was reactivated and upgraded, a data acquisition system was configured and upgraded several times, several facility calibrations were performed and test entries with a wedge model with hydrogen injection and a full scramjet combustor model, with hydrogen injection, were performed. Extensive CFD modeling of the flow in the facility was done. This includes modeling of the unsteady flow in the driver and driven tubes and steady flow modeling of the nozzle flow. Other modeling efforts include simulations of non-equilibrium flows and turbulence, plasmas, light gas guns and the use of non-ideal gas equations of state. New experimental techniques to improve the performance of gas guns, shock tubes and tunnels and scramjet combustors were conceived and studied computationally. Ways to improve scramjet engine performance using steady and pulsed detonation waves were also studied computationally. A number of studies were performed on the operation of the ram accelerator, including investigations of in-tube gasdynamic heating and the use of high explosives to raise the velocity capability of the device.
High precision Hugoniot measurements on statically pre-compressed fluid helium

DOE PAGES

Seagle, Christopher T.; Reinhart, William D.; Lopez, Andrew J.; ...

2016-09-27

Here we describe how the capability for statically pre-compressing fluid targets for Hugoniot measurements utilizing gas gun driven flyer plates has been developed. Pre-compression expands the capability for initial condition control, allowing access to thermodynamic states off the principal Hugoniot. Absolute Hugoniot measurements with an uncertainty less than 3% on density and pressure were obtained on statically pre-compressed fluid helium utilizing a two stage light gas gun. Helium is highly compressible; the locus of shock states resulting from dynamic loading of an initially compressed sample at room temperature is significantly denser than the cryogenic fluid Hugoniot even for relatively modestmore » (0.27–0.38 GPa) initial pressures. Lastly, the dynamic response of pre-compressed helium in the initial density range of 0.21–0.25 g/cm3 at ambient temperature may be described by a linear shock velocity (us) and particle velocity (u p) relationship: u s = C 0 + su p, with C 0 = 1.44 ± 0.14 km/s and s = 1.344 ± 0.025.« less
46 CFR 28.410 - Deck rails, lifelines, storm rails, and hand grabs.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false Deck rails, lifelines, storm rails, and hand grabs. 28..., lifelines, storm rails, and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section... with a bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab...
46 CFR 28.410 - Deck rails, lifelines, storm rails, and hand grabs.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 1 2014-10-01 2014-10-01 false Deck rails, lifelines, storm rails, and hand grabs. 28..., lifelines, storm rails, and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section... with a bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab...
46 CFR 28.810 - Deck rails, lifelines, storm rails and hand grabs.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false Deck rails, lifelines, storm rails and hand grabs. 28..., storm rails and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section, deck... bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab must be...
46 CFR 28.810 - Deck rails, lifelines, storm rails and hand grabs.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 1 2011-10-01 2011-10-01 false Deck rails, lifelines, storm rails and hand grabs. 28..., storm rails and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section, deck... bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab must be...
46 CFR 28.810 - Deck rails, lifelines, storm rails and hand grabs.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false Deck rails, lifelines, storm rails and hand grabs. 28..., storm rails and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section, deck... bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab must be...
46 CFR 28.410 - Deck rails, lifelines, storm rails, and hand grabs.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 1 2013-10-01 2013-10-01 false Deck rails, lifelines, storm rails, and hand grabs. 28..., lifelines, storm rails, and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section... with a bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab...

46 CFR 28.410 - Deck rails, lifelines, storm rails, and hand grabs.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 1 2012-10-01 2012-10-01 false Deck rails, lifelines, storm rails, and hand grabs. 28..., lifelines, storm rails, and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section... with a bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab...
46 CFR 28.410 - Deck rails, lifelines, storm rails, and hand grabs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Deck rails, lifelines, storm rails, and hand grabs. 28..., lifelines, storm rails, and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section... with a bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab...
46 CFR 28.810 - Deck rails, lifelines, storm rails and hand grabs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Deck rails, lifelines, storm rails and hand grabs. 28..., storm rails and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section, deck... bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab must be...
46 CFR 28.810 - Deck rails, lifelines, storm rails and hand grabs.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 1 2014-10-01 2014-10-01 false Deck rails, lifelines, storm rails and hand grabs. 28..., storm rails and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section, deck... bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab must be...
Effects of a Gun Dealer's Change in Sales Practices on the Supply of Guns to Criminals

PubMed Central

Vernick, Jon S.; Bulzacchelli, Maria T.

2006-01-01

Licensed gun dealers are a major conduit for gun trafficking. Prior to May 1999, a single gun store sold more than half of the guns recovered from criminals in Milwaukee, WI, shortly following retail sale. On May 10, 1999, the store stopped selling small, inexpensive handguns popular with criminals, often called “Saturday night specials.” The purpose of this study was to estimate the effect of this gun store's changed sales practices on criminals' acquisition of new guns. We used an interrupted time-series design with comparisons to test for changes in the number of guns that police recovered from criminals within a year of retail sale following the gun dealer's new sales policy. The dealer's changed sales policy was associated with a 96% decrease in recently sold, small, inexpensive handguns use in crime in Milwaukee, a 73% decrease in crime guns recently sold by this dealer, and a 44% decrease in the flow of all new, trafficked guns to criminals in Milwaukee. The findings demonstrate the substantial impact that a single gun store's sales practices can have on the supply of new guns to criminals. Proposed anti-gun-trafficking efforts in other cities could benefit from targeting problem retail outlets. PMID:16937085
Development of a two-stage light gas gun to accelerate hydrogen pellets to high speeds for plasma fueling applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Combs, S.K.; Milora, S.L.; Foust, C.R.

1989-05-01

The development of a two-stage light gas gun to accelerate hydrogen isotope pellets to high speeds is under way at Oak Ridge National Laboratory. High velocities (>2 km/s) are desirable for plasma fueling applications, since the faster pellets can penetrate more deeply into large, hot plasmas and deposit atoms of fuel directly in a larger fraction of the plasma volume. In the initial configuration of the two-stage device, a 2.2-1 volume (less than or equal to55 bar) provides the gas to accelerate a 25.4-mm-diam piston in a 1-m-long pump tube; a burst disk or a fast valve initiates the accelerationmore » process in the first stage. As the piston travels the length of the pump tube, the downstream gas (initially at <1 bar) is compressed (to pressures up to 2600 bar) and thus is driven to high temperature (approx. =5000 K). This provides the driving force for acceleration of a 4-mm pellet in a 1-m-long gun barrel. In preliminary tests using helium as the driver in both stages, 35-mg plastic pellets have been accelerated to speeds as high as 4.0 km/s. Projectiles composed of hydrogen ice will have a mass in the range from 5 to 20 mg ( rhoapprox. =0.087, 0.20, and 0.32 g/cm/sup 3/ for frozen hydrogen isotopes). However, the use of sabots to encase and protect the cryogenic pellets from the high peak pressures will probably be required to realize speeds of approx. =3 km/s or greater. The experimental plan includes acceleration of hydrogen isotopes as soon as the gun geometry and operating parameters are optimized; theoretical models are being used to aid in this process. The hardware is being designed to accommodate repetitive operation, which is the objective of this research and is required for future applications.« less
Development of a two-stage light gas gun to accelerate hydrogen pellets to high speeds for plasma fueling applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Combs, S.K.; Milora, S.L.; Foust, C.R.

1988-01-01

The development of a two-stage light gas gun to accelerate hydrogen isotope pellets to high speeds is under way at Oak Ridge National Laboratory. High velocities (>2 km/s) are desirable for plasma fueling applications, since the faster pellets can penetrate more deeply into large, hot plasmas and deposit atoms of fuel directly in a larger fraction of the plasma volume. In the initial configuration of the two-stage device, a 2.2-l volume (/<=/55-bar) provides the gas to accelerate a 25.4-mm-diam piston in a 1-m-long pump tube; a burst disk or a fast valve initiates the acceleration process in the first stage.more » As the piston travels the length of the pump tube, the downstream gas (initially at <1 bar) is compressed (to pressures up to 2600 bar) and thus is driven to high temperature (approx.5000 K). This provides the driving force for acceleration of a 4-mm pellet in a 1-m-long gun barrel. In preliminary tests using helium as the driver in both stages, 35-mg plastic pellets have been accelerated to speeds as high as 3.8 km/s. Projectiles composed of hydrogen ice will have a mass in the range from 5 to 20 mg (/rho/ approx. 0.087, 0.20, and 0.32 g/cm/sup 3/ for frozen hydrogen isotopes). However, the use of sabots to encase and protect the cryogenic pellets from the high peak pressures will probably be required to realize speeds of approx.3 km/s or greater. The experimental plan includes acceleration of hydrogen isotopes as soon as the gun geometry and operating parameters are optimized; theoretical models are being used to aid in this process. The hardware is being designed to accommodate repetitive operation, which is the objective of this research and is required for future applications. 25 refs., 6 figs., 1 tab.« less
Present developments and status of electron sources for high power gyrotron tubes and free electron masers

NASA Astrophysics Data System (ADS)

Thumm, M.

1997-02-01

Gyrotron oscillators are mainly used as high power mm-wave sources for start-up, electron cyclotron heating (ECH) and diagnostics of magnetically confined plasmas for controlled thermonuclear fusion research. 140 GHz (110 GHz) gyrotrons with output power Pout = 0.55 MW (0.93 MW), pulse length τ = 3.0 s (2.0 s) and efficiency η = 40% (38%) are commercially available. Total efficiencies around 50% have been achieved using single-stage depressed collectors. Diagnostic gyrotrons deliver Pout = 40 kW with τ = 40 μs at frequencies up to 650 GHz ( η≥4%). Recently, gyrotron oscillators have also been successfully used in materials processing, for example sintering of high performance, structural and functional ceramics. Such technological applications require gyrotrons with f≥24 GHz, Pout = 10-100 kW, CW, η≥30%. This paper reports on recent achievements in the development of very high power mm-wave gyrotron oscillators for long pulse or CW operation. In addition a short overview of the present development status of gyrotrons for technological applications, gyroklystron amplifiers, gyro-TWT amplifiers, cyclotron autoresonance masers (CARMs) and free electron masers (FEMs) is given. The most impressive FEM output parameters are: Pout = 2GW, τ = 20 ns, η = 13% at 140 GHz (LLNL) and Pout = 15 kW, τ = 20 μs, η = 5% in the range from 120 to 900 GHz (UCSB). In gyro-devices, magnetron injection guns (MIGs) operating in the temperature limited current regime have thus far been used most successfully. Diode guns as well as triode guns with a modulating anode are employed. Tests of a MIG operated under space-charge limited conditions have been not very successful. Electrostatic CW FEMs are driven by thermionic Pierce guns whereas pulsed high power devices employ many types of accelerators as drivers for example pulse-line accelerators, microtrons and induction or rf linacs, using field and photo emission cathodes.
Wear Enhancement of Wheel-Rail Interaction by Ultrasonic Nanocrystalline Surface Modification Technique.

PubMed

Chang, Seky; Pyun, Young-Sik; Amanov, Auezhan

2017-02-16

In this study, an ultrasonic nanocrystalline surface modification (UNSM) technique was applied to normal and heat-treated rails made of 60 kgK steel to enhance the wear resistance of the wheel-rail interaction. The hardness and compressive residual stress values of the untreated and UNSM-treated rails were measured by the Brinell hardness tester and X-ray diffraction technique, respectively. It was found, according to the measurement results, that the hardness was increased by about 20% and 8%, whereas the compressive residual stress was induced by about 52% and 62% for the UNSM-treated normal and heat-treated rails, respectively. The UNSM-treated normal rail showed a slightly higher hardness than the heat-treated rail. The wear resistance of rails with respect to rotating speed and rolling time was assessed using a rolling contact wear (RCW) tester under dry conditions. The RCW test results revealed that the wear of the UNSM-treated rails was enhanced in comparison with those of the untreated rails. Also, the wear amount of the rails was increased with increasing the rotation speed. The UNSM-treated normal rail exhibited the highest wear resistance with respect to the rotation speed. The wear mechanisms of the rails are also discussed based on microscopic images of the worn out surfaces.
Wear Enhancement of Wheel-Rail Interaction by Ultrasonic Nanocrystalline Surface Modification Technique

PubMed Central

Chang, Seky; Pyun, Young-Sik; Amanov, Auezhan

2017-01-01

In this study, an ultrasonic nanocrystalline surface modification (UNSM) technique was applied to normal and heat-treated rails made of 60 kgK steel to enhance the wear resistance of the wheel-rail interaction. The hardness and compressive residual stress values of the untreated and UNSM-treated rails were measured by the Brinell hardness tester and X-ray diffraction technique, respectively. It was found, according to the measurement results, that the hardness was increased by about 20% and 8%, whereas the compressive residual stress was induced by about 52% and 62% for the UNSM-treated normal and heat-treated rails, respectively. The UNSM-treated normal rail showed a slightly higher hardness than the heat-treated rail. The wear resistance of rails with respect to rotating speed and rolling time was assessed using a rolling contact wear (RCW) tester under dry conditions. The RCW test results revealed that the wear of the UNSM-treated rails was enhanced in comparison with those of the untreated rails. Also, the wear amount of the rails was increased with increasing the rotation speed. The UNSM-treated normal rail exhibited the highest wear resistance with respect to the rotation speed. The wear mechanisms of the rails are also discussed based on microscopic images of the worn out surfaces. PMID:28772549
Crashworthiness evaluation of light rail vehicle interiors.

DOT National Transportation Integrated Search

2011-12-01

Statistically, light rail transit (LRT) systems have higher injury rates on a perpassengermile basis than heavy rail and commuter rail systems, because in most cities, light rail vehicles (LRVs) operate on city streets. Passenger safety is depe...
National University Rail Transportation Center : Tier 1 : final report.

DOT National Transportation Integrated Search

2016-10-17

This project was a collaborative effort between Michigan Techs Rail Transportation Program (RTP), a member of the National University Rail Center (NURail) and the Michigan Dept of Transportation (MDOT), Office of Rail to advance rail transportatio...
Effects of Exposure to Gun Violence in Movies on Children's Interest in Real Guns.

PubMed

Dillon, Kelly P; Bushman, Brad J

2017-11-01

More US children die by accidental gun use than children in other developed countries. One factor that can influence children's interest in guns is exposure to media containing guns. To test whether children who see a movie containing guns will handle a real gun longer and will pull the trigger more times than children who see the same movie not containing guns. One hundred four children aged 8 to 12 years recruited through advertisements were randomly assigned in pairs to watch a 20-minute PG-rated movie containing or not containing guns in a university laboratory. Children then played with toys and games in a room for 20 minutes while being video recorded. A cabinet in the room contained a real (disabled) gun with a sensor counting trigger pulls. Recordings were coded for the time spent holding the gun and in aggressive play. Data were collected from July 15, 2015, through January 1, 2016, and analyzed using generalized estimating equations (Tweedie log-link for time spent holding the gun; Poisson log-link for pulling the trigger). The 2 main outcomes were time spent holding the gun and the number of trigger pulls. Control variables included sex, age, trait aggressiveness, exposure to violent media, interest in guns, and number of guns at home. Among the 104 study participants (62 boys [59.6%] and 42 girls [40.4%]; mean (SD) age, 9.9 [1.5] years), the adjusted median number of trigger pulls among children who saw the movie containing guns was 2.8 (interquartile range [IQR], 0.2-2.8) compared with 0.01 (IQR, 0.01-0.2) among children who saw the movie not containing guns (adjusted odds ratio, 22.3; 95% CI, 6.0-83.4; P < .001). The adjusted median number of seconds spent holding the gun among children who saw a movie containing guns was 53.1 (IQR, 35.5-53.1) compared with 11.1 (IQR, 10.7-16.7) among children who saw the movie not containing guns (adjusted odds ratio, 3.0; 95% CI, 0.9-9.9; P = .07). Qualitative analyses on 4 pairs from each condition found that children who saw the movie containing guns also played more aggressively and sometimes fired the gun at people (ie, self, partner, or passersby on street). Children in the United States frequently have access to unsecured firearms and frequently consume media containing guns. This experiment shows that children who see movie characters use guns are more likely to use guns themselves. clinicaltrials.gov Identifier NCT03220412.
Solar panel truss mounting systems and methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the basemore » rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.« less
Estimation of rail wear limits based on rail strength investigations

DOT National Transportation Integrated Search

1998-12-01

This report describes analyses performed to estimate limits on rail wear based on strength investigations. Two different failure modes are considered in this report: (1) permanent plastic bending, and (2) rail fracture. Rail bending stresses are calc...
2000 Montana state rail plan update

DOT National Transportation Integrated Search

2000-01-01

This 2000 Montana Rail Plan Update is a comprehensive update of the State Rail Plan. The purpose of this update is to review the State's role in rail planning, retain eligibility for Local Rail Freight Assistance (LRFA) funding, update the descriptio...
49 CFR 37.83 - Remanufacture of rail vehicles and purchase or lease of remanufactured rail vehicles by public...

Code of Federal Regulations, 2010 CFR

2010-10-01

... lease of remanufactured rail vehicles by public entities operating rapid or light rail systems. 37.83... operating rapid or light rail systems. (a) This section applies to any public entity operating a rapid or... operates a rapid or light rail system any segment of which is included on the National Register of Historic...
49 CFR 37.83 - Remanufacture of rail vehicles and purchase or lease of remanufactured rail vehicles by public...

Code of Federal Regulations, 2014 CFR

2014-10-01

... lease of remanufactured rail vehicles by public entities operating rapid or light rail systems. 37.83... operating rapid or light rail systems. (a) This section applies to any public entity operating a rapid or... operates a rapid or light rail system any segment of which is included on the National Register of Historic...
49 CFR 37.83 - Remanufacture of rail vehicles and purchase or lease of remanufactured rail vehicles by public...

Code of Federal Regulations, 2011 CFR

2011-10-01

... lease of remanufactured rail vehicles by public entities operating rapid or light rail systems. 37.83... operating rapid or light rail systems. (a) This section applies to any public entity operating a rapid or... operates a rapid or light rail system any segment of which is included on the National Register of Historic...
49 CFR 37.83 - Remanufacture of rail vehicles and purchase or lease of remanufactured rail vehicles by public...

Code of Federal Regulations, 2013 CFR

2013-10-01

... lease of remanufactured rail vehicles by public entities operating rapid or light rail systems. 37.83... operating rapid or light rail systems. (a) This section applies to any public entity operating a rapid or... operates a rapid or light rail system any segment of which is included on the National Register of Historic...

49 CFR 37.83 - Remanufacture of rail vehicles and purchase or lease of remanufactured rail vehicles by public...

Code of Federal Regulations, 2012 CFR

2012-10-01

... lease of remanufactured rail vehicles by public entities operating rapid or light rail systems. 37.83... operating rapid or light rail systems. (a) This section applies to any public entity operating a rapid or... operates a rapid or light rail system any segment of which is included on the National Register of Historic...
Interpreting the empirical evidence on illegal gun market dynamics.

PubMed

Braga, Anthony A; Wintemute, Garen J; Pierce, Glenn L; Cook, Philip J; Ridgeway, Greg

2012-10-01

Thousands of Americans are killed by gunfire each year, and hundreds of thousands more are injured or threatened with guns in robberies and assaults. The burden of gun violence in urban areas is particularly high. Critics suggest that the results of firearm trace data and gun trafficking investigation studies cannot be used to understand the illegal supply of guns to criminals and, therefore, that regulatory and enforcement efforts designed to disrupt illegal firearms markets are futile in addressing criminal access to firearms. In this paper, we present new data to address three key arguments used by skeptics to undermine research on illegal gun market dynamics. We find that criminals rely upon a diverse set of illegal diversion pathways to acquire guns, gun traffickers usually divert small numbers of guns, newer guns are diverted through close-to-retail diversions from legal firearms commerce, and that a diverse set of gun trafficking indicators are needed to identify and shut down gun trafficking pathways.
Development of spray guns for the application of rigid foam insulation

NASA Technical Reports Server (NTRS)

Allen, Peter B.

1993-01-01

The paper describes the activities initiated to improve the existing spray gun system used for spraying insulating foam on the External Tank of the Space Shuttle, due to the quality variations of the applied foam noted in the past. Consideration is given to the two tasks of the project: (1) investigations of possible improvements, as an interim measure, to the spray gun currently used to apply the large acreage spray-on-foam insulation and the evaluation of other commercial equipment; and (2) the design and fabrication of a new automatic spray gun. The design and operation of the currently used Binks 43 PA spray gun are described together with several new breadboard spray guns designed and fabricated and the testing procedures developed. These new guns include the Modular Automatic Foam spray gun, the Ball Valve spray gun, and the Tapered Plug Valve (TPV) gun. As a result of tests, the TPV spray gun is recommended to replace the currently used automatic spray gun.
Multi-point contact of the high-speed vehicle-turnout system dynamics

NASA Astrophysics Data System (ADS)

Ren, Zunsong

2013-05-01

The wheel-rail contact problems, such as the number, location and the track of contact patches, are very important for optimizing the spatial structure of the rails and lowering the vehicle-turnout system dynamics. However, the above problems are not well solved currently because of having the difficulties in how to determine the multi-contact, to preciously present the changeable profiles of the rails and to establish an accurate spatial turnout system dynamics model. Based on a high-speed vehicle-turnout coupled model in which the track is modeled as flexible with rails and sleepers represented by beams, the line tracing extreme point method is introduced to investigate the wheel-rail multiple contact conditions and the key sections of the blade rail, longer nose rail, shorter rail in the switch and nose rail area are discretized to represent the varying profiles of rails in the turnout. The dynamic interaction between the vehicle and turnout is simulated for cases of the vehicle divergently passing the turnout and the multi-point contact is obtained. The tracks of the contact patches on the top of the rails are presented and the wheel-rail impact forces are offered in comparison with the contact patches transference on the rails. The numerical simulation results indicate that the length of two-point contact occurrence of a worn wheel profile and rails is longer than that of the new wheel profile and rails; The two-point contact definitely occurs in the switch and crossing area. Generally, three-point contact doesn't occur for the new rail profile, which is testified by the wheel-rails interpolation distance and the first order derivative function of the tracing line extreme points. The presented research is not only helpful to optimize the structure of the turnout, but also useful to lower the dynamics of the high speed vehicle-turnout system.
78 FR 66840 - Revocation of Certain Requirements Pertaining to Caps Intended for Use With Toy Guns and Toy Guns...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-07

... Certain Requirements Pertaining to Caps Intended for Use With Toy Guns and Toy Guns Not Intended for Use... regulations pertaining to caps intended for use with toy guns refer to obsolete equipment, but the ASTM F963... revokes the existing regulations pertaining to caps intended for use with toy guns and toy guns not...
Movements of radio-marked California Ridgway's rails during monitoring surveys: Implications for population monitoring

USGS Publications Warehouse

Bui, Thuy-Vy D.; Takekawa, John Y.; Overton, Cory T.; Schultz, Emily R.; Hull, Joshua M.; Casazza, Michael L.

2015-01-01

The California Ridgway's rail Rallus obsoletus obsoletus (hereafter California rail) is a secretive marsh bird endemic to tidal marshes in the San Francisco Bay (hereafter bay) of California. The California rail has undergone significant range contraction and population declines due to a variety of factors, including predation and the degradation and loss of habitat. Call-count surveys, which include call playbacks, based on the standardized North American marsh bird monitoring protocol have been conducted throughout the bay since 2005 to monitor population size and distribution of the California rail. However, call-count surveys are difficult to evaluate for efficacy or accuracy. To measure the accuracy of call-count surveys and investigate whether radio-marked California rails moved in response to call-count surveys, we compared locations of radio-marked California rails collected at frequent intervals (15 min) to California rail detections recorded during call-count surveys conducted over the same time periods. Overall, 60% of radio-marked California rails within 200 m of observers were not detected during call-count surveys. Movements of radio-marked California rails showed no directional bias (P = 0.92) irrespective of whether or not playbacks of five marsh bird species (including the California rail) were broadcast from listening stations. Our findings suggest that playbacks of rail vocalizations do not consistently influence California rail movements during surveys. However, call-count surveys may underestimate California rail presence; therefore, caution should be used when relating raw numbers of call-count detections to population abundance.
Characteristics of a gun exchange program, and an assessment of potential benefits

PubMed Central

Romero, M.; Wintemute, G.; Vernick, J.

1998-01-01

Objectives—To describe a gun exchange program and assess potential benefits for participants and host communities. Methods—Mail survey of participants in a Sacramento, California gun exchange program, August 1993; the response rate was 79%. Comparative data were obtained from nationwide polls of gun owners. Results—Most (62%) respondents were men; 40% were more than 55 years old; none was less than 25. Concern that children might find and use the gun was the most frequently cited reason for participating (46% of respondents). Of 141 firearms exchanged, 72% were handguns; 23% of respondents indicated that the guns they turned in were not in working order. Of respondents who owned a gun at the time of the program (rather than those who owned no guns and turned in a gun owned by someone else), 41% owned no guns after participating; the prevalence of handgun ownership declined from 79% to 32%. Those who continued to own guns were as likely as gun owners nationwide to keep a gun loaded in the house (odds ratio (OR) 0.9, 95% confidence interval (CI) 0.4 to 1.7) or to carry a gun with them (OR 1.5, 95% CI 0.6 to 3.8). Conclusions—Gun exchange programs may reduce risk for firearm violence among some participants, but a number of factors limit their overall benefits to host communities. PMID:9788092
Large Bore Powder Gun Qualification (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rabern, Donald A.; Valdiviez, Robert

A Large Bore Powder Gun (LBPG) is being designed to enable experimentalists to characterize material behavior outside the capabilities of the NNSS JASPER and LANL TA-55 PF-4 guns. The combination of these three guns will create a capability to conduct impact experiments over a wide range of pressures and shock profiles. The Large Bore Powder Gun will be fielded at the Nevada National Security Site (NNSS) U1a Complex. The Complex is nearly 1000 ft below ground with dedicated drifts for testing, instrumentation, and post-shot entombment. To ensure the reliability, safety, and performance of the LBPG, a qualification plan has beenmore » established and documented here. Requirements for the LBPG have been established and documented in WE-14-TR-0065 U A, Large Bore Powder Gun Customer Requirements. The document includes the requirements for the physics experiments, the gun and confinement systems, and operations at NNSS. A detailed description of the requirements is established in that document and is referred to and quoted throughout this document. Two Gun and Confinement Systems will be fielded. The Prototype Gun will be used primarily to characterize the gun and confinement performance and be the primary platform for qualification actions. This gun will also be used to investigate and qualify target and diagnostic modifications through the life of the program (U1a.104 Drift). An identical gun, the Physics Gun, will be fielded for confirmatory and Pu experiments (U1a.102D Drift). Both guns will be qualified for operation. The Gun and Confinement System design will be qualified through analysis, inspection, and testing using the Prototype Gun for the majority of process. The Physics Gun will be qualified through inspection and a limited number of qualification tests to ensure performance and behavior equivalent to the Prototype gun. Figure 1.1 shows the partial configuration of U1a and the locations of the Prototype and Physics Gun/Confinement Systems.« less
Rail-to-rail differential input amplification stage with main and surrogate differential pairs

DOEpatents

Britton, Jr., Charles Lanier; Smith, Stephen Fulton

2007-03-06

An operational amplifier input stage provides a symmetrical rail-to-rail input common-mode voltage without turning off either pair of complementary differential input transistors. Secondary, or surrogate, transistor pairs assume the function of the complementary differential transistors. The circuit also maintains essentially constant transconductance, constant slew rate, and constant signal-path supply current as it provides rail-to-rail operation.
Gun Play

ERIC Educational Resources Information Center

Mechling, Jay

2008-01-01

Biology and the particular gun culture of the United States come together to explain the persistent and powerful attraction of American boys to both real guns and toy guns. The 1990s saw adults begin to conflate "the gun problem" with "the boy problem," sparking attempts (largely failed) to banish toy guns from homes and…
Gun Attitudes and Fear of Crime.

ERIC Educational Resources Information Center

Heath, Linda; Weeks, Kyle; Murphy, Marie Mackay

1997-01-01

Using three studies, examined the relationship between attitudes toward guns and fear of crime. Findings indicate a connection between fear of crime and attitudes toward guns: people higher in fear of crime favored gun control. Results also established a relationship between stereotypical beliefs about gun victims and support for gun control. (RJM)
Analysis of minimum rail size in heavy axle load environment

DOT National Transportation Integrated Search

2013-04-15

The effects of increasing axle loads on rail integrity are examined in this paper. In the present context, rail integrity refers to the prevention and control of rail failures. Rail failures usually occur because cracks or defects develop and grow fr...
Developing course lecture notes on high-speed rail.

DOT National Transportation Integrated Search

2017-07-15

1. Introduction a. World-wide Development of High-Speed Rail (Japan, Europe, China) b. High-speed Rail in the U.S. 2. High-Speed Rail Infrastructure a. Geometric Design of High Speed Rail i. Horizontal Curve ii. Vertical Curve iii. Grade and Turnout ...
Gun shows across a multistate American gun market: observational evidence of the effects of regulatory policies.

PubMed

Wintemute, Garen J

2007-06-01

To describe gun shows and assess the impact of increased regulation on characteristics linked to their importance as sources of guns used in crime. Cross-sectional, observational. Data were collected at a structured sample of 28 gun shows in California, which regulates these events and prohibits undocumented private party gun sales; and in Arizona, Nevada, Texas and Florida-all leading sources of California's crime guns--where these restrictions do not exist. Size of shows, measured by numbers of gun vendors and people in attendance; number and nature of guns for sale by gun vendors; measures of private party gun sales and illegal surrogate ("straw") gun purchases. Shows in comparison states were larger, but the number of attendees per gun vendor was higher in California. None of these differences was statistically significant. Armed attendees were more common in other states (median 5.7%, interquartile range (IQR) 3.9-10.0%) than in California (median 1.1%, IQR 0.5-2.2%), p = 0.0007. Thirty percent of gun vendors both in California and elsewhere were identifiable as licensed firearm retailers. There were few differences in the types or numbers of guns offered for sale; vendors elsewhere were more likely to sell assault weapons (34.9% and 13.3%, respectively; p = 0.001). Straw purchases were more common in the comparison states (rate ratio 6.6 (95% CI 0.9 to 49.1), p = 0.06). California's regulatory policies were associated with a decreased incidence of anonymous, undocumented gun sales and illegal straw purchases at gun shows. No significant adverse effects of these policies were observed.
Frequency of Guns in the Households of High School Seniors*

PubMed Central

Coker, Ann L.; Bush, Heather M.; Follingstad, Diane R.; Brancato, Candace J.

2017-01-01

BACKGROUND In 2013, President Obama lifted the federal ban on gun violence research. The current study provides one of the first reports to estimate household gun ownership as reported by youth. METHODS In this cohort study of 3006 high school seniors from 24 schools, we examined the frequency of household guns ownership. RESULTS About 65% reported having at least 1 gun in their household. White males were more likely to have a gun and to have more guns than other demographically characterized groups. After adjustment for race and sex, those of higher income, who lived in suburban or rural areas, identified as being exclusively attracted to the opposite sex, and in a romantic relationship, were more likely to have a gun in their household. Having a gun was not associated with increasing symptoms of depression or current poor physical or mental health. CONCLUSIONS Whereas we cannot determine gun types or reasons for having a gun, this research indicates that high school seniors are aware of and may have access to guns for use other than their intended purpose. Household gun ownership among students at higher risk for violence may pose safety challenges for communities and schools. PMID:28147456
Frequency of Guns in the Households of High School Seniors.

PubMed

Coker, Ann L; Bush, Heather M; Follingstad, Diane R; Brancato, Candace J

2017-03-01

In 2013, President Obama lifted the federal ban on gun violence research. The current study provides one of the first reports to estimate household gun ownership as reported by youth. In this cohort study of 3006 high school seniors from 24 schools, we examined the frequency of household guns ownership. About 65% reported having at least 1 gun in their household. White males were more likely to have a gun and to have more guns than other demographically characterized groups. After adjustment for race and sex, those of higher income, who lived in suburban or rural areas, identified as being exclusively attracted to the opposite sex, and in a romantic relationship, were more likely to have a gun in their household. Having a gun was not associated with increasing symptoms of depression or current poor physical or mental health. Whereas we cannot determine gun types or reasons for having a gun, this research indicates that high school seniors are aware of and may have access to guns for use other than their intended purpose. Household gun ownership among students at higher risk for violence may pose safety challenges for communities and schools. © 2017, American School Health Association.
Assessment of Rail Seat Abrasion Patterns and Environment

DOT National Transportation Integrated Search

2012-05-01

Rail seat abrasion (RSA) of concrete ties is manifested by the loss of material under the rail seat area and, in extreme cases, results in loss of rail clip holding power, reverse rail cant, and gauge widening. RSA was measured in several curves on t...
78 FR 59316 - Rail Vehicles Access Advisory Committee Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-26

...-0001] RIN 3014-AA42 Rail Vehicles Access Advisory Committee Meetings AGENCY: Architectural and... Vehicles Access Advisory Committee (Committee) will hold its first meeting. We, the Architectural and... transportation vehicles that operate on fixed guideway systems (e.g., rapid rail, light rail, commuter rail...
Field homogeneity improvement of maglev NdFeB magnetic rails from joints.

PubMed

Li, Y J; Dai, Q; Deng, C Y; Sun, R X; Zheng, J; Chen, Z; Sun, Y; Wang, H; Yuan, Z D; Fang, C; Deng, Z G

2016-01-01

An ideal magnetic rail should provide a homogeneous magnetic field along the longitudinal direction to guarantee the reliable friction-free operation of high temperature superconducting (HTS) maglev vehicles. But in reality, magnetic field inhomogeneity may occur due to lots of reasons; the joint gap is the most direct one. Joint gaps inevitably exist between adjacent segments and influence the longitudinal magnetic field homogeneity above the rail since any magnetic rails are consisting of many permanent magnet segments. To improve the running performance of maglev systems, two new rail joints are proposed based on the normal rail joint, which are named as mitered rail joint and overlapped rail joint. It is found that the overlapped rail joint has a better effect to provide a competitive homogeneous magnetic field. And the further structure optimization has been done to ensure maglev vehicle operation as stable as possible when passing through those joint gaps. The results show that the overlapped rail joint with optimal parameters can significantly reduce the magnetic field inhomogeneity comparing with the other two rail joints. In addition, an appropriate gap was suggested when balancing the thermal expansion of magnets and homogenous magnetic field, which is considered valuable references for the future design of the magnetic rails.
Women and Guns. Firearm Facts.

ERIC Educational Resources Information Center

Duker, Laurie, Ed.

Many gun manufacturers market guns to women claiming a gun can provide protection. Statistics provided in this fact sheet indicate gun ownership may provide a false sense of security that can be fatal, since the greatest threat to a woman comes from the people and guns within her own home. Contrary to "typical" scenarios created by advertisers,…

Physicians Asking Patients About Guns: Promoting Patient Safety, Respecting Patient Rights.

PubMed

Parent, Brendan

2016-10-01

Recent debate on whether physicians should discuss gun ownership with their patients has centered on determining whether gun injuries are an issue of health or safety, and on protecting patient privacy. Yet, physicians' duties span personal health, public health, and safety spheres, and they often must address private patient matters. To prioritize gun safety and reduce gun injuries, the primary policy-driving question should be: will physician counseling on gun ownership effectively reduce gun-related injuries without interfering with the physician's other treatment obligations or compromising the physician-patient relationship? Existing data on physician-initiated conversations with patients about guns support a positive prevention effect. However, it is critical that physician-initiated discussions of safe gun practices are not motivated by, nor convey, disapproval of gun ownership. To be ethical, respectful, and efficient, the conversation should be standard between primary care providers and all of their patients (not limited to patient subsets); questions and education should be limited to topics of gun-ownership risks and storage practices; and the conversation must be framed without bias against gun ownership.
Intercity passenger rail : assessing the benefits of increased federal funding for Amtrak and high-speed passenger rail systems

DOT National Transportation Integrated Search

2001-03-21

The Rail Passenger Service Act of 1970 created Amtrak to provide intercity passenger rail service. Like other major national intercity passenger rail systems in the world, Amtrak has received substantial government support-nearly $24 billion for capi...
46 CFR 169.329 - Storm rails.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...
46 CFR 169.329 - Storm rails.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...
46 CFR 169.329 - Storm rails.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...
46 CFR 169.329 - Storm rails.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...
46 CFR 169.329 - Storm rails.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...
Racism, Gun Ownership and Gun Control: Biased Attitudes in US Whites May Influence Policy Decisions

PubMed Central

O’Brien, Kerry; Forrest, Walter; Lynott, Dermot; Daly, Michael

2013-01-01

Objective Racism is related to policies preferences and behaviors that adversely affect blacks and appear related to a fear of blacks (e.g., increased policing, death penalty). This study examined whether racism is also related to gun ownership and opposition to gun controls in US whites. Method The most recent data from the American National Election Study, a large representative US sample, was used to test relationships between racism, gun ownership, and opposition to gun control in US whites. Explanatory variables known to be related to gun ownership and gun control opposition (i.e., age, gender, education, income, conservatism, anti-government sentiment, southern vs. other states, political identification) were entered in logistic regression models, along with measures of racism, and the stereotype of blacks as violent. Outcome variables included; having a gun in the home, opposition to bans on handguns in the home, support for permits to carry concealed handguns. Results After accounting for all explanatory variables, logistic regressions found that for each 1 point increase in symbolic racism there was a 50% increase in the odds of having a gun at home. After also accounting for having a gun in the home, there was still a 28% increase in support for permits to carry concealed handguns, for each one point increase in symbolic racism. The relationship between symbolic racism and opposition to banning handguns in the home (OR1.27 CI 1.03,1.58) was reduced to non-significant after accounting for having a gun in the home (OR1.17 CI.94,1.46), which likely represents self-interest in retaining property (guns). Conclusions Symbolic racism was related to having a gun in the home and opposition to gun control policies in US whites. The findings help explain US whites’ paradoxical attitudes towards gun ownership and gun control. Such attitudes may adversely influence US gun control policy debates and decisions. PMID:24204867
Racism, gun ownership and gun control: biased attitudes in US whites may influence policy decisions.

PubMed

O'Brien, Kerry; Forrest, Walter; Lynott, Dermot; Daly, Michael

2013-01-01

Racism is related to policies preferences and behaviors that adversely affect blacks and appear related to a fear of blacks (e.g., increased policing, death penalty). This study examined whether racism is also related to gun ownership and opposition to gun controls in US whites. The most recent data from the American National Election Study, a large representative US sample, was used to test relationships between racism, gun ownership, and opposition to gun control in US whites. Explanatory variables known to be related to gun ownership and gun control opposition (i.e., age, gender, education, income, conservatism, anti-government sentiment, southern vs. other states, political identification) were entered in logistic regression models, along with measures of racism, and the stereotype of blacks as violent. Outcome variables included; having a gun in the home, opposition to bans on handguns in the home, support for permits to carry concealed handguns. After accounting for all explanatory variables, logistic regressions found that for each 1 point increase in symbolic racism there was a 50% increase in the odds of having a gun at home. After also accounting for having a gun in the home, there was still a 28% increase in support for permits to carry concealed handguns, for each one point increase in symbolic racism. The relationship between symbolic racism and opposition to banning handguns in the home (OR1.27 CI 1.03,1.58) was reduced to non-significant after accounting for having a gun in the home (OR1.17 CI.94,1.46), which likely represents self-interest in retaining property (guns). Symbolic racism was related to having a gun in the home and opposition to gun control policies in US whites. The findings help explain US whites' paradoxical attitudes towards gun ownership and gun control. Such attitudes may adversely influence US gun control policy debates and decisions.
Improved performances of CIBER-X: a new tabletop laser-driven electron and x-ray source

NASA Astrophysics Data System (ADS)

Girardeau-Montaut, Jean-Pierre; Kiraly, Bela; Girardeau-Montaut, Claire

2000-11-01

We present the most recent data concerning the performances of the table-top laser driven electron and x-ray source developed in our laboratory. X-ray pulses are produced by a three-step process which consists of the photoelectron emission from a thin metallic photocathode illuminated by 16 ps duration laser pulse at 213 nm. The e-gun is a standard pierce diode electrode type, in which electrons are accelerated by a cw electric fields of 12 MV/m. The photoinjector produced a train of 90 - 100 keV electron pulses of approximately 1 nC and 40 A peak current at a repetition rate of 10 Hz. The electrons, transported outside the diode, are focused onto a target of thulium by magnetic fields produced by two electromagnetic coils to produce x-rays. Applications to low dose imagery of inert and living materials are also presented.
Effects of Initial Conditions on Shock Driven Flows

NASA Astrophysics Data System (ADS)

Martinez, Adam A.; Mula, Swathi M.; Charonko, John; Prestridge, Kathy

2017-11-01

The spatial and temporal evolution of shock-driven, variable density flows, such as the Richtmyer Meshkov (RM) instability, are strongly influenced by the initial conditions (IC's) of the flow at the time of interaction with shockwave. We study the effects of the IC's on the Vertical Shock Tube (VST) and on flows from Mach =1.2 to Mach =9. Experiments at the VST are of an Air-SF6 (At =0.6) multimode interface. Perturbations are generated using a shear layer with a flapper plate. Planar Laser Induced Fluorescence (PLIF) is used to characterize the IC's. New experiments are occurring using the Powder Gun driver at LANL Proton Radiography (pRad) facility. Mach number up to M =9 accelerate a Xenon-Helium (At =0.94) interface that is perturbed using a membrane supported by different sized grids. This presentation focuses on how to design and characterize different types of initial conditions for experiments.
Gun carrying by high school students in Boston, MA: does overestimation of peer gun carrying matter?

PubMed

Hemenway, David; Vriniotis, Mary; Johnson, Renee M; Miller, Matthew; Azrael, Deborah

2011-10-01

This paper investigates: (1) whether high school students overestimate gun carrying by their peers, and (2) whether those students who overestimate peer gun carrying are more likely to carry firearms. Data come from a randomly sampled survey conducted in 2008 of over 1,700 high school students in Boston, MA. Over 5% of students reported carrying a gun, 9% of boys and 2% of girls. Students substantially overestimated the percentage of their peers who carried guns; the likelihood that a respondent carried a gun was strongly associated with their perception of the level of peer gun carrying. Most respondents believed it was easier for other youth to obtain guns than it was for them. Social marketing campaigns designed to lower young people's perceptions about the prevalence of peer gun carrying may be a promising strategy for reducing actual gun carrying among youth. Copyright © 2010 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.
76 FR 77716 - Alternate Passenger Rail Service Pilot Program

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-14

... program that permits a rail carrier or rail carriers that own infrastructure over which Amtrak operates... develops a pilot program that permits a rail carrier or rail carriers that own infrastructure over which... the infrastructure as described in Sec. 269.7 of this final rule. In addition, such information...
Simulation of rail yard emissions transport to the near-source environment

EPA Science Inventory

Rail yards are critical nodes in the freight transportation network and locations of clustered emission sources. When people reside in close proximity to an active rail yard, the near-field effect of rail yard emissions is of concern. Field characterization of near-rail yard ai...
46 CFR 169.327 - Deck rails.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.327 Deck rails. (a) All rails or lifelines must be at least 30 inches high... through bolted or welded to the deck. (b) Rails or lifelines must consist of evenly spaced courses. The...
46 CFR 169.327 - Deck rails.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.327 Deck rails. (a) All rails or lifelines must be at least 30 inches high... through bolted or welded to the deck. (b) Rails or lifelines must consist of evenly spaced courses. The...
46 CFR 169.327 - Deck rails.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Deck rails. 169.327 Section 169.327 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.327 Deck rails. (a) All rails or lifelines must be at least 30 inches high...
46 CFR 169.327 - Deck rails.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Deck rails. 169.327 Section 169.327 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.327 Deck rails. (a) All rails or lifelines must be at least 30 inches high...
76 FR 22747 - RailAmerica, Inc., Palm Beach Holdings, Inc., RailAmerica Transportation Corp., RailTex, Inc...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-22

...., Palm Beach Holdings, Inc., RailAmerica Transportation Corp., RailTex, Inc., Fortress Investment Group, LLC, and RR Acquisition Holding, LLC--Continuance in Control Exemption-- Conecuh Valley Railway, LLC...), Fortress Investment Group, LLC (Fortress), and RR Acquisition Holding, LLC (RR Acquisition) (collectively...
46 CFR 177.920 - Storm rails.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must be...

46 CFR 177.920 - Storm rails.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must be...
46 CFR 108.221 - Storm rails.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the following...
46 CFR 177.920 - Storm rails.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must be...
46 CFR 108.221 - Storm rails.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the following...
46 CFR 108.221 - Storm rails.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the following...
46 CFR 108.221 - Storm rails.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the following...
46 CFR 127.320 - Storm rails.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and at...
46 CFR 127.320 - Storm rails.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and at...
46 CFR 177.920 - Storm rails.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must be...
46 CFR 127.320 - Storm rails.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and at...
46 CFR 127.320 - Storm rails.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and at...
46 CFR 177.920 - Storm rails.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must be...
46 CFR 108.221 - Storm rails.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the following...
46 CFR 127.320 - Storm rails.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and at...
Not an 'iron pipeline', but many capillaries: regulating passive transactions in Los Angeles' secondary, illegal gun market.

PubMed

Chesnut, Kelsie Y; Barragan, Melissa; Gravel, Jason; Pifer, Natalie A; Reiter, Keramet; Sherman, Nicole; Tita, George E

2017-08-01

California has strict firearm-related laws and is exceptional in its regulation of firearms retailers. Though evidence suggests that these laws can reduce illegal access to guns, high levels of gun violence persist in Los Angeles (LA), California. This research seeks to describe the sources of guns accessed by active offenders in LA, California and reports offenders' motivations for obtaining guns. Los Angeles County Jail (LACJ) system (four facilities). Random sampling from a screened pool of eligible participants was used to conduct qualitative semistructured interviews with 140 incarcerated gun offenders in one of four (LACJ) facilities. Researchers collected data on firearm acquisition, experiences related to gun violence, and other topics, using a validated survey instrument. Grounded theory guided the collection and analysis of data. Respondents reported possession of 77 specific guns (79.2% handguns) collectively. Social networks facilitate access to illegal guns; the majority of interviewees acquired their illegal guns through a social connection (85.7%) versus an outside broker/unregulated retailer (8.5%). Most guns were obtained through illegal purchase (n=51) or gift (n=15). A quarter of gun purchasers report engaging in a passive transaction, or one initiated by another party. Passive gun buyers were motivated by concerns for personal safety and/or economic opportunity. In LA's illegal gun market, where existing social relationships facilitate access to guns across a diffuse network, individuals, influenced by both fear and economic opportunity, have frequent opportunities to illegally possess firearms through passive transactions. Gun policies should better target and minimise these transactions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
Gun shows across a multistate American gun market: observational evidence of the effects of regulatory policies

PubMed Central

Wintemute, Garen J

2007-01-01

Objective To describe gun shows and assess the impact of increased regulation on characteristics linked to their importance as sources of guns used in crime. Design Cross‐sectional, observational. Subjects Data were collected at a structured sample of 28 gun shows in California, which regulates these events and prohibits undocumented private party gun sales; and in Arizona, Nevada, Texas and Florida—all leading sources of California's crime guns—where these restrictions do not exist. Main outcome measures Size of shows, measured by numbers of gun vendors and people in attendance; number and nature of guns for sale by gun vendors; measures of private party gun sales and illegal surrogate (“straw”) gun purchases. Results Shows in comparison states were larger, but the number of attendees per gun vendor was higher in California. None of these differences was statistically significant. Armed attendees were more common in other states (median 5.7%, interquartile range (IQR) 3.9–10.0%) than in California (median 1.1%, IQR 0.5–2.2%), p = 0.0007. Thirty percent of gun vendors both in California and elsewhere were identifiable as licensed firearm retailers. There were few differences in the types or numbers of guns offered for sale; vendors elsewhere were more likely to sell assault weapons (34.9% and 13.3%, respectively; p = 0.001). Straw purchases were more common in the comparison states (rate ratio 6.6 (95% CI 0.9 to 49.1), p = 0.06). Conclusions California's regulatory policies were associated with a decreased incidence of anonymous, undocumented gun sales and illegal straw purchases at gun shows. No significant adverse effects of these policies were observed. PMID:17567968
The case for moderate gun control.

PubMed

DeGrazia, David

2014-03-01

In addressing the shape of appropriate gun policy, this essay assumes for the sake of discussion that there is a legal and moral right to private gun ownership. My thesis is that, against the background of this right, the most defensible policy approach in the United States would feature moderate gun control. The first section summarizes the American gun control status quo and characterizes what I call "moderate gun control." The next section states and rebuts six leading arguments against this general approach to gun policy. The section that follows presents a positive case for moderate gun control that emphasizes safety in the home and society as well as rights whose enforcement entails some limits or qualifications on the right to bear arms. A final section shows how the recommended gun regulations address legitimate purposes, rather than imposing arbitrary restrictions on gun rights, and offers concluding reflections.
Goods for Guns--the use of a gun buyback as an injury prevention/community education tool.

PubMed

McGuire, Margaret; Manno, Mariann; Rook, Allison; Maranda, Louise; Renaud, Elizabeth; DeRoss, Anthony; Hirsh, Michael

2011-11-01

US children aged between 5 years and 14 years have a rate of gun-related homicide 17 times higher and a rate of gun-related suicide and unintentional firearm injury 10 times higher than other developed countries. Gun buyback programs have been criticized as ineffective interventions in decreasing violence. The Injury Free Coalition for Kids-Worcester (IFCK-W) Goods for Guns buyback is a multipronged approach to address these concerns and to reduce the number of firearms in the community. The IFCK-W buyback program is funded by corporate sponsors, grants, and individual donations. Citizens are instructed to transport guns, ammunition, and weapons safely to police headquarters on two Saturdays in December. Participants are guaranteed anonymity by the District Attorney's office and receive gift certificates for operable guns. Trained volunteers administer an anonymous survey to willing participants. Individuals who disclose having unsafely stored guns remaining at home receive educational counseling and trigger locks. Guns and ammunition are destroyed at a later time in a gun crushing ceremony. Since 2002, 1,861 guns (444 rifle/shotgun, 738 pistol/revolver, and 679 automatic/semiautomatic) have been collected at a cost of $99,250 (average, $53/gun). Seven hundred ten people have surrendered firearms, 534 surveys have been administered, and ≈ 75 trigger locks have been distributed per year. IFCK-W Goods for Guns is a relatively inexpensive injury prevention model program that removes unwanted firearms from homes, raises community awareness about gun safety, and provides high-risk individuals with trigger locks and educational counseling.
Interior of southeast gun chamber (labeled "Gun Turret No. Two), ...

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

Interior of southeast gun chamber (labeled "Gun Turret No. Two), showing gun mounting pad, wall rings, small niche, and opening to outside - U.S. Naval Base, Pearl Harbor, Battery Adair, Princeton Place, Pearl City, Honolulu County, HI
46 CFR 160.031-4 - Equipment for shoulder gun type line-throwing appliance.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 6 2014-10-01 2014-10-01 false Equipment for shoulder gun type line-throwing appliance... Appliance, Shoulder Gun Type (and Equipment) § 160.031-4 Equipment for shoulder gun type line-throwing... the gun. The line canister shall be secured by clamps or brackets below the barrel of the gun. (c) One...

46 CFR 160.031-4 - Equipment for shoulder gun type line-throwing appliance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 6 2010-10-01 2010-10-01 false Equipment for shoulder gun type line-throwing appliance... Appliance, Shoulder Gun Type (and Equipment) § 160.031-4 Equipment for shoulder gun type line-throwing... the gun. The line canister shall be secured by clamps or brackets below the barrel of the gun. (c) One...
46 CFR 160.031-4 - Equipment for shoulder gun type line-throwing appliance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 6 2013-10-01 2013-10-01 false Equipment for shoulder gun type line-throwing appliance... Appliance, Shoulder Gun Type (and Equipment) § 160.031-4 Equipment for shoulder gun type line-throwing... the gun. The line canister shall be secured by clamps or brackets below the barrel of the gun. (c) One...
46 CFR 160.031-4 - Equipment for shoulder gun type line-throwing appliance.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 6 2012-10-01 2012-10-01 false Equipment for shoulder gun type line-throwing appliance... Appliance, Shoulder Gun Type (and Equipment) § 160.031-4 Equipment for shoulder gun type line-throwing... the gun. The line canister shall be secured by clamps or brackets below the barrel of the gun. (c) One...
46 CFR 160.031-4 - Equipment for shoulder gun type line-throwing appliance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 6 2011-10-01 2011-10-01 false Equipment for shoulder gun type line-throwing appliance... Appliance, Shoulder Gun Type (and Equipment) § 160.031-4 Equipment for shoulder gun type line-throwing... the gun. The line canister shall be secured by clamps or brackets below the barrel of the gun. (c) One...
Gun Violence, Mental Illness, And Laws That Prohibit Gun Possession: Evidence From Two Florida Counties

PubMed Central

Swanson, Jeffrey W.; Easter, Michele M.; Robertson, Allison G.; Swartz, Marvin S.; Alanis-Hirsch, Kelly; Moseley, Daniel; Dion, Charles; Petrila, John

2016-01-01

Gun violence kills about ninety people every day in the United States, a toll measured in wasted and ruined lives and with an annual economic price tag exceeding $200 billion. Some policy makers suggest that reforming mental health care systems and improving point-of-purchase background checks to keep guns from mentally disturbed people will address the problem. Epidemiological research shows that serious mental illness contributes little to the risk of interpersonal violence but is a strong factor in suicide, which accounts for most firearm fatalities. Meanwhile, the effectiveness of gun restrictions focused on mental illness remains poorly understood. This article examines gun-related suicide and violent crime in people with serious mental illnesses, and whether legal restrictions on firearm sales to people with a history of mental health adjudication are effective in preventing gun violence. Among the study population in two large Florida counties, we found that 62 percent of violent gun crime arrests and 28 percent of gun suicides involved individuals not legally permitted to have a gun at the time. Suggested policy reforms include enacting risk-based gun removal laws and prohibiting guns from people involuntarily detained in short-term psychiatric hospitalizations. PMID:27269024
Association Between Substance Use and Gun-Related Behaviors

PubMed Central

Chen, Danhong; Wu, Li-Tzy

2016-01-01

Gun-related violence is a public health concern. This study synthesizes findings on associations between substance use and gun-related behaviors. Searches through PubMed, Embase, and PsycINFO located 66 studies published in English between 1992 and 2014. Most studies found a significant bivariate association between substance use and increased odds of gun-related behaviors. However, their association after adjustment was mixed, which could be attributed to a number of factors such as variations in definitions of substance use and gun activity, study design, sample demographics, and the specific covariates considered. Fewer studies identified a significant association between substance use and gun access/possession than other gun activities. The significant association between nonsubstance covariates (e.g., demographic covariates and other behavioral risk factors) and gun-related behaviors might have moderated the association between substance use and gun activities. Particularly, the strength of association between substance use and gun activities tended to reduce appreciably or to become nonsignificant after adjustment for mental disorders. Some studies indicated a positive association between the frequency of substance use and the odds of engaging in gun-related behaviors. Overall, the results suggest a need to consider substance use in research and prevention programs for gun-related violence. PMID:26769722
75 FR 51331 - Draft Tier II Environmental Impact Statement: Southeast High Speed Rail Corridor-Richmond, VA...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-19

... Carolina Department of Transportation Rail Division (NCDOT) and the Virginia Department of Rail and Public... Raleigh,'' in the subject heading; or Ms. Christine Fix, Department of Rail & Public Transportation, 600... Department of Rail and Public Transportation Office at 600 East Main Street, Suite 2102, Richmond, VA; and...
49 CFR 174.59 - Marking and placarding of rail cars.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Marking and placarding of rail cars. 174.59... RAIL General Handling and Loading Requirements § 174.59 Marking and placarding of rail cars. No person may transport a rail car carrying hazardous materials unless it is marked and placarded as required by...
49 CFR 174.59 - Marking and placarding of rail cars.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Marking and placarding of rail cars. 174.59... RAIL General Handling and Loading Requirements § 174.59 Marking and placarding of rail cars. No person may transport a rail car carrying hazardous materials unless it is marked and placarded as required by...
49 CFR 174.59 - Marking and placarding of rail cars.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Marking and placarding of rail cars. 174.59... RAIL General Handling and Loading Requirements § 174.59 Marking and placarding of rail cars. No person may transport a rail car carrying hazardous materials unless it is marked and placarded as required by...
49 CFR 174.59 - Marking and placarding of rail cars.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Marking and placarding of rail cars. 174.59... RAIL General Handling and Loading Requirements § 174.59 Marking and placarding of rail cars. No person may transport a rail car carrying hazardous materials unless it is marked and placarded as required by...
49 CFR 174.59 - Marking and placarding of rail cars.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Marking and placarding of rail cars. 174.59... RAIL General Handling and Loading Requirements § 174.59 Marking and placarding of rail cars. No person may transport a rail car carrying hazardous materials unless it is marked and placarded as required by...
46 CFR 72.40-10 - Storm rails.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 3 2010-10-01 2010-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...
46 CFR 72.40-10 - Storm rails.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 3 2013-10-01 2013-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...
46 CFR 72.40-10 - Storm rails.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 3 2011-10-01 2011-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...
46 CFR 72.40-10 - Storm rails.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 3 2012-10-01 2012-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...
46 CFR 72.40-10 - Storm rails.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 3 2014-10-01 2014-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...
49 CFR 212.231 - Highway-rail grade crossing inspector.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Highway-rail grade crossing inspector. 212.231... § 212.231 Highway-rail grade crossing inspector. (a) The highway-rail grade crossing inspector is required, at a minimum, to be able to conduct independent inspections of all types of highway-rail grade...
49 CFR 212.231 - Highway-rail grade crossing inspector.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Highway-rail grade crossing inspector. 212.231... § 212.231 Highway-rail grade crossing inspector. (a) The highway-rail grade crossing inspector is required, at a minimum, to be able to conduct independent inspections of all types of highway-rail grade...
49 CFR 212.231 - Highway-rail grade crossing inspector.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Highway-rail grade crossing inspector. 212.231... § 212.231 Highway-rail grade crossing inspector. (a) The highway-rail grade crossing inspector is required, at a minimum, to be able to conduct independent inspections of all types of highway-rail grade...

46 CFR 190.25-5 - Where rails required.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Where rails required. 190.25-5 Section 190.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS CONSTRUCTION AND ARRANGEMENT Rails and Guards § 190.25-5 Where rails required. (a) All vessels shall have efficient guard rails...
NCHRP report 350 test 3-11 of the modified T8 bridge rail.

DOT National Transportation Integrated Search

2009-04-01

A new flexible bridge rail system, referred to as the T8 rail, was designed as a replacement for the T6 rail in high-speed applications on culverts and thin deck structures. The T8 rail failed a crash test when the breakaway posts failed the thin dec...
77 FR 54655 - Genesee & Wyoming Inc.-Control-RailAmerica, Inc., et al.

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-05

... & Wyoming Inc.--Control--RailAmerica, Inc., et al. AGENCY: Surface Transportation Board. ACTION: Decision No... August 6, 2012, by Genesee and Wyoming Inc. (GWI) and RailAmerica, Inc. (RailAmerica). The application seeks Board approval under 49 U.S.C. 11323-11325 of the acquisition of control of RailAmerica, a...
The life cycle of crime guns: a description based on guns recovered from young people in California.

PubMed

Wintemute, Garen J; Romero, Michael P; Wright, Mona A; Grassel, Kevin M

2004-06-01

We describe the life cycle of crime guns recovered from young people-the movement of those guns from manufacture to criminal use-and identify associations between the characteristics of those guns and their possessors, purchasers, sellers, and places of origin. This is a cross-sectional study of data from gun ownership tracing records compiled by the Bureau of Alcohol, Tobacco, Firearms and Explosives for 2,121 crime guns recovered in California from persons younger than 25 years and traced in 1999. Purchaser and seller data for handguns were updated when possible by linking to California handgun sales records. The 2,121 traced guns were recovered from 1,717 young people. Guns recovered from persons aged 21 to 24 years were most frequently also purchased by persons aged 21 to 24 years; those recovered from persons younger than 18 years were most often purchased by persons aged 45 years or older. Small-caliber handguns made up 41.0% of handguns recovered from persons younger than 18 years but 25.2% of handguns recovered from persons aged 21 to 24 years. The median time from sale to recovery (commonly called time to crime) for all guns was 6.4 years (interquartile range 2.7 to 12.4 years). A time to crime of less than 3 years, suggesting deliberate gun trafficking, was observed for 17.3% of guns recovered from persons younger than 18 years but 34.6% of guns recovered from persons aged 21 to 24 years. Ten retailers who sold 10 or more traced guns accounted for 13.1% of all guns traced to a retailer. Handguns whose purchaser and possessor were the same person were more likely than others to be large-caliber semiautomatic pistols (29.3% and 11.7%, respectively); their median time to crime was 0.2 years (69 days). Analysis of crime-gun ownership traces reveals patterns that may help refine gun violence prevention efforts and render them more effective.
Phosphorylation of GENOMES UNCOUPLED 4 Alters Stimulation of Mg Chelatase Activity in Angiosperms1[OPEN

PubMed Central

Hochheuser, Caroline; Fufezan, Christian; Heinze, Laura

2016-01-01

GENOMES UNCOUPLED 4 (GUN4) is a positive regulator of light-dependent chlorophyll biosynthesis. GUN4 activates Mg chelatase (MgCh) that catalyzes the insertion of an Mg2+ ion into protoporphyrin IX. We show that Arabidopsis (Arabidopsis thaliana) GUN4 is phosphorylated at Ser 264 (S264), the penultimate amino acid residue at the C terminus. While GUN4 is preferentially phosphorylated in darkness, phosphorylation is reduced upon accumulation of Mg porphyrins. Expression of a phosphomimicking GUN4(S264D) results in an incomplete complementation of the white gun4-2 null mutant and a chlorotic phenotype comparable to gun4 knockdown mutants. Phosphorylated GUN4 has a reduced stimulatory effect on MgCh in vitro and in vivo but retains its protein stability and tetrapyrrole binding capacity. Analysis of GUN4 found in oxygenic photosynthetic organisms reveals the evolution of a C-terminal extension, which harbors the phosphorylation site of GUN4 expressed in angiosperms. Homologs of GUN4 from Synechocystis and Chlamydomonas lack the conserved phosphorylation site found in a C-terminal extension of angiosperm GUN4. Biochemical studies proved the importance of the C-terminal extension for MgCh stimulation and inactivation of GUN4 by phosphorylation in angiosperms. An additional mechanism regulating MgCh activity is proposed. In conjunction with the dark repression of 5-aminolevulinic acid synthesis, GUN4 phosphorylation minimizes the flow of intermediates into the Mg branch of the tetrapyrrole metabolic pathway for chlorophyll biosynthesis. PMID:27688621
Optimization of wheel-rail interface friction using top-of-rail friction modifiers: State of the art

NASA Astrophysics Data System (ADS)

Khan, M. Roshan; Dasaka, Satyanarayana Murty

2018-05-01

High Speed Railways and Dedicated Freight Corridors are the need of the day for fast and efficient transportation of the ever growing population and freight across long distances of travel. With the increase in speeds and axle loads carried by these trains, wearing out of rails and train wheel sections are a common issue, which is due to the increase in friction at the wheel-rail interfaces. For the cases where the wheel-rail interface friction is less than optimum, as in case of high speed trains with very low axle loads, wheel-slips are imminent and loss of traction occurs when the trains accelerate rapidly or brake all of a sudden. These vast variety of traction problems around the wheel-rail interface friction need to be mitigated carefully, so that the contact interface friction neither ascents too high to cause material wear and need for added locomotive power, nor be on the lower side to cause wheel-slips and loss of traction at high speeds. Top-of-rail friction modifiers are engineered surface coatings applied on top of rails, to maintain an optimum frictional contact between the train wheels and the rails. Extensive research works in the area of wheel-rail tribology have revealed that the optimum frictional coefficients at wheel-rail interfaces lie at a value of around 0.35. Application of top-of-rail (TOR) friction modifiers on rail surfaces add an extra layer of material coating on top of the rails, with a surface frictional coefficient of the desired range. This study reviews the common types of rail friction modifiers, the methods for their application, issues related with the application of friction modifiers, and a guideline on selection of the right class of coating material based on site specific requirements of the railway networks.
Identification and prioritization of rail squat defects in the field using rail magnetisation technology

NASA Astrophysics Data System (ADS)

Kaewunruen, Sakdirat

2015-04-01

Inevitably, rail squats and studs are continuing to be a serious problem for railway organisations around the world in the 21st century. They are typically classified as the growth of any cracks that have grown longitudinally through the subsurface and some of the cracks propagating to the bottom of rails transversely, and have branched from initial longitudinal cracks with a depression of rail surface. The horizontal crack, which results in a depression of rail surface, induces increased maintenance level, more frequent monitoring, compromised rail testing (as the crack shields the signal echoes), and possible broken rails. This paper presents field investigations using a magnetised-rail testing device developed by MRX Technologies to identify and prioritise the rail squats. Most of the in situ squats were found on the high rail of the transition (variable-radius curved track), which is associated with rolling contact fatigue (RCF). This investigation highlights the field performance of the MRX's surface crack detection technology in comparison with the traditional ultrasonic method and detailed walking inspection. Visually, it was found in the field that the size of the RCF squats varies from very small to moderate. The predicted crack data were obtained by scanning the magnitised rails. The comparison of the actual crack depths (ultrasonic) and the predicted crack depths (MRX device) shows: • A possible correlation for small RCF/ squat cracks. • Poor interpretation of larger defects and welds. The field assessment also suggests some practical issues required for further development, including the detection of rail spalling, deep transverse crack, welding, and so on.
Track-monitoring from the dynamic response of an operational train

NASA Astrophysics Data System (ADS)

Lederman, George; Chen, Siheng; Garrett, James; Kovačević, Jelena; Noh, Hae Young; Bielak, Jacobo

2017-03-01

We explore a data-driven approach for monitoring rail infrastructure from the dynamic response of a train in revenue-service. Presently, track inspection is performed either visually or with dedicated track geometry cars. In this study, we examine a more economical approach where track inspection is performed by analyzing vibration data collected from an operational passenger train. The high frequency with which passenger trains travel each section of track means that faults can be detected sooner than with dedicated inspection vehicles, and the large number of passes over each section of track makes a data-driven approach statistically feasible. We have deployed a test-system on a light-rail vehicle and have been collecting data for the past two years. The collected data underscores two of the main challenges that arise in train-based track monitoring: the speed of the train at a given location varies from pass to pass and the position of the train is not known precisely. In this study, we explore which feature representations of the data best characterize the state of the tracks despite these sources of uncertainty (i.e., in the spatial domain or frequency domain), and we examine how consistently change detection approaches can identify track changes from the data. We show the accuracy of these different representations, or features, and different change detection approaches on two types of track changes, track replacement and tamping (a maintenance procedure to improve track geometry), and two types of data, simulated data and operational data from our test-system. The sensing, signal processing, and data analysis we propose in the study could facilitate safer trains and more cost-efficient maintenance in the future. Moreover, the proposed approach is quite general and could be extended to other parts of the infrastructure, including bridges.
Impurities, temperature, and density in a miniature electrostatic plasma and current source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Den Hartog, D.J.; Craig, D.J.; Fiksel, G.

1996-10-01

We have spectroscopically investigated the Sterling Scientific miniature electrostatic plasma source-a plasma gun. This gun is a clean source of high density (10{sup 19} - 10{sup 20} m{sup -3}), low temperature (5 - 15 eV) plasma. A key result of our investigation is that molybdenum from the gun electrodes is largely trapped in the internal gun discharge; only a small amount escapes in the plasma flowing out of the gun. In addition, the gun plasma parameters actually improve (even lower impurity contamination and higher ion temperature) when up to 1 kA of electron current is extracted from the gun viamore » the application of an external bias. This improvement occurs because the internal gun anode no longer acts as the current return for the internal gun discharge. The gun plasma is a virtual plasma electrode capable of sourcing an electron emission current density of 1 kA/cm{sup 2}. The high emission current, small size (3 - 4 cm diameter), and low impurity generation make this gun attractive for a variety of fusion and plasma technology applications.« less
Research on vibration characteristics of gun barrel based on contact model

NASA Astrophysics Data System (ADS)

Zhao, Yang; Zhou, Qizheng; Yue, Pengfei

2017-04-01

In order to study vibration characteristics of the gun barrel under the action of moving projectile, the gun barrel is simplified to cross sectional cantilever beam such as Euler. Considering contact conditions of inertia effect and projectile with the gun barrel, the equation of lateral vibration of the gun barrel is established under the projectile-gun coupling effect; the modal analysis method is used to give the analytic solutions of equation series. The effect of the motion parameters the projectile on the vibration of gun barrel is discussed, and characteristics of vibration of gun barrel are further studied under two conditions of repeating and projectile with mass eccentricity. The research results show that reasonable control of the acceleration of the projectile in the gun bore, and reduction of projectile mass eccentricity can help reduce the muzzle vibration at the gun firing. The research results can provide reference for overall design of the gun, and the modeling and analysis method used in the paper can be promoted for the solution of vibration of other related projects under the moving excitation.
Power System Implementation and Demonstration at Camp Katuu, Palau

DTIC Science & Technology

2011-05-11

Horizontal Rows 3 Vertical Rows 3 Vertical Rows with Center Walkway 6 Vertical Rows 1 Amount of rail mounting (lf) 1440’ 1800’ 1800’ 1440’ 2 Ease of rail...installation some rail cutting required to clear walkway requires two level rail mounting system requires two level rail mounting system no rail...Maintenance access 21" horizontal & vertical walkway , does not have direct access to all panels Accessible with 15" walkways Direct access to each panel and
NASA's Decadal Planning Team Mars Mission Analysis Summary

NASA Astrophysics Data System (ADS)

Drake, Bret G.

2007-02-01

In June 1999 the NASA Administrator chartered an internal NASA task force, termed the Decadal Planning Team, to create new integrated vision and strategy for space exploration. The efforts of the Decadal Planning Team evolved into the Agency-wide team known as the NASA Exploration Team (NEXT). This team was also instructed to identify technology roadmaps to enable the science-driven exploration vision, established a cross-Enterprise, cross-Center systems engineering team with emphasis focused on revolutionary not evolutionary approaches. The strategy of the DPT and NEXT teams was to "Go Anywhere, Anytime" by conquering key exploration hurdles of space transportation, crew health and safety, human/robotic partnerships, affordable abundant power, and advanced space systems performance. Early emphasis was placed on revolutionary exploration concepts such as rail gun and electromagnetic launchers, propellant depots, retrograde trajectories, nano structures, and gas core nuclear rockets to name a few. Many of these revolutionary concepts turned out to be either not feasible for human exploration missions or well beyond expected technology readiness for near-term implementation. During the DPT and NEXT study cycles, several architectures were analyzed including missions to the Earth-Sun Libration Point (L2), the Earth-Moon Gateway and L1, the lunar surface, Mars (both short and long stays), one-year round trip Mars, and near-Earth asteroids. Common emphasis of these studies included utilization of the Earth-Moon Libration Point (L1) as a staging point for exploration activities, current (Shuttle) and near-term launch capabilities (EELV), advanced propulsion, and robust space power. Although there was much emphasis placed on utilization of existing launch capabilities, the team concluded that missions in near-Earth space are only marginally feasible and human missions to Mars were not feasible without a heavy lift launch capability. In addition, the team concluded that missions in Earth s neighborhood, such as to the Moon, can serve as stepping-stones toward further deep-space missions in terms of proving systems, technologies, and operational concepts. The material contained in this presentation was compiled to capture the work performed by the Mars Sub-Team of the DPT NEXT efforts in the late 1999-2001 timeframe.
NASA's Decadal Planning Team Mars Mission Analysis Summary

NASA Technical Reports Server (NTRS)

Drake, Bret G. (Editor)

2007-01-01

In June 1999 the NASA Administrator chartered an internal NASA task force, termed the Decadal Planning Team, to create new integrated vision and strategy for space exploration. The efforts of the Decadal Planning Team evolved into the Agency-wide team known as the NASA Exploration Team (NEXT). This team was also instructed to identify technology roadmaps to enable the science-driven exploration vision, established a cross-Enterprise, cross-Center systems engineering team with emphasis focused on revolutionary not evolutionary approaches. The strategy of the DPT and NEXT teams was to "Go Anywhere, Anytime" by conquering key exploration hurdles of space transportation, crew health and safety, human/robotic partnerships, affordable abundant power, and advanced space systems performance. Early emphasis was placed on revolutionary exploration concepts such as rail gun and electromagnetic launchers, propellant depots, retrograde trajectories, nano structures, and gas core nuclear rockets to name a few. Many of these revolutionary concepts turned out to be either not feasible for human exploration missions or well beyond expected technology readiness for near-term implementation. During the DPT and NEXT study cycles, several architectures were analyzed including missions to the Earth-Sun Libration Point (L2), the Earth-Moon Gateway and L1, the lunar surface, Mars (both short and long stays), one-year round trip Mars, and near-Earth asteroids. Common emphasis of these studies included utilization of the Earth-Moon Libration Point (L1) as a staging point for exploration activities, current (Shuttle) and near-term launch capabilities (EELV), advanced propulsion, and robust space power. Although there was much emphasis placed on utilization of existing launch capabilities, the team concluded that missions in near-Earth space are only marginally feasible and human missions to Mars were not feasible without a heavy lift launch capability. In addition, the team concluded that missions in Earth s neighborhood, such as to the Moon, can serve as stepping-stones toward further deep-space missions in terms of proving systems, technologies, and operational concepts. The material contained in this presentation was compiled to capture the work performed by the Mars Sub-Team of the DPT NEXT efforts in the late 1999-2001 timeframe.
The Gun Dispute.

ERIC Educational Resources Information Center

Spitzer, Robert J.

1999-01-01

Explores the debate over gun ownership and gun control in the United States, focusing on the historic place of guns in U.S. society. The current national mood is more receptive than ever to restricting and regulating adolescent access to guns in light of recent school shootings. (SLD)
49 CFR 213.352 - Torch cut rail.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...
49 CFR 37.89 - Remanufacture of intercity and commuter rail cars and purchase or lease of remanufactured...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 1 2012-10-01 2012-10-01 false Remanufacture of intercity and commuter rail cars and purchase or lease of remanufactured intercity and commuter rail cars. 37.89 Section 37.89... commuter rail cars and purchase or lease of remanufactured intercity and commuter rail cars. (a) This...
49 CFR 37.89 - Remanufacture of intercity and commuter rail cars and purchase or lease of remanufactured...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 1 2013-10-01 2013-10-01 false Remanufacture of intercity and commuter rail cars and purchase or lease of remanufactured intercity and commuter rail cars. 37.89 Section 37.89... commuter rail cars and purchase or lease of remanufactured intercity and commuter rail cars. (a) This...
49 CFR 213.352 - Torch cut rail.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...
46 CFR 190.25-10 - Storm rails.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...
46 CFR 92.25-10 - Storm rails.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Storm rails. 92.25-10 Section 92.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 92.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

46 CFR 190.25-10 - Storm rails.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...
46 CFR 190.25-10 - Storm rails.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...
46 CFR 92.25-10 - Storm rails.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Storm rails. 92.25-10 Section 92.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 92.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...
46 CFR 92.25-10 - Storm rails.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Storm rails. 92.25-10 Section 92.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 92.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...
46 CFR 92.25-10 - Storm rails.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Storm rails. 92.25-10 Section 92.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 92.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...
46 CFR 190.25-10 - Storm rails.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...
46 CFR 190.25-10 - Storm rails.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...
46 CFR 92.25-10 - Storm rails.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Storm rails. 92.25-10 Section 92.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 92.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...
78 FR 36017 - MCM Rail Services LLC, d/b/a Baltimore Industrial Railroad-Operation Exemption-Hilco SP Rail, LLC

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-14

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35725] MCM Rail Services LLC, d/b/a Baltimore Industrial Railroad-- Operation Exemption--Hilco SP Rail, LLC MCM Rail Services LLC, d/b/a Baltimore Industrial Railroad (MCM), a noncarrier, has filed a verified notice of exemption...
76 FR 16538 - Solid Waste Rail Transfer Facilities

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-24

... circumstances. Upon receiving a land-use-exemption permit issued by the Board, a solid waste rail transfer... new application for a land-use-exemption permit if the rail line associated with the solid waste rail... transportation of solid waste by rail. (2) The Board will not grant a land-use-exemption permit for a solid waste...
Optimization of a two stage light gas gun. M.S. Thesis

NASA Technical Reports Server (NTRS)

Rynearson, R. J.; Rand, J. L.

1972-01-01

Performance characteristics of the Texas A&M University light gas gun are presented along with a review of basic gun theory and popular prediction methods. A computer routine based on the simple isentropic compression method is discussed. Results from over 60 test shots are given which demonstrate an increase in gun muzzle velocity from 9.100 ft/sec. to 19,000 ft/sec. The data gathered indicated the Texas A&M light gas gun more closely resembles an isentropic compression gun rather than a shock compression gun.
Big data and ergonomics methods: A new paradigm for tackling strategic transport safety risks.

PubMed

Walker, Guy; Strathie, Ailsa

2016-03-01

Big data collected from On-Train Data Recorders (OTDR) has the potential to address the most important strategic risks currently faced by rail operators and authorities worldwide. These risk issues are increasingly orientated around human performance and have proven resistant to existing approaches. This paper presents a number of proof of concept demonstrations to show that long standing ergonomics methods can be driven from big data, and succeed in providing insight into human performance in a novel way. Over 300 ergonomics methods were reviewed and a smaller sub-set selected for proof-of-concept development using real on-train recorder data. From this are derived nine candidate Human Factors Leading Indicators which map on to all of the psychological precursors of the identified risks. This approach has the potential to make use of a significantly underused source of data, and enable rail industry stakeholders to intervene sooner to address human performance issues that, via the methods presented in this paper, are clearly manifest in on-train data recordings. The intersection of psychological knowledge, ergonomics methods and big data creates an important new framework for driving new insights. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.
Safety assessment of underground vehicles passing over highly resilient curved tracks in the presence of a broken rail

NASA Astrophysics Data System (ADS)

Suárez, B.; Rodriguez, P.; Vázquez, M.; Fernández, I.

2012-01-01

Vehicle-track interaction for a new resilient slab track designed to reduce noise and vibration levels was analysed, in order to assess the derailment risk on a curved track when encountering a broken rail. Sensitivity of the rail support spacing of the relative position of the rail breakage between two adjacent rail supports and of running speed were analysed for two different elasticities of the rail fastening system. In none of the cases analysed was observed an appreciable difference between either of the elastic systems. As was expected, the most unfavourable situations were those with greater rail support spacing and those with greater distance from the breakage to the nearest rail support, although in none of the simulations performed did a derailment occur when running over the broken rail. When varying the running speed, the most favourable condition was obtained for an intermediate speed, due to the superposition of two antagonistic effects.
Correlates of Gun Involvement and Aggressiveness among Adolescents.

ERIC Educational Resources Information Center

Ding, Cody S.; Nelsen, Edward A.; Lassonde, Cynthia T.

2002-01-01

Investigated adolescents' aggressiveness in relation to their experiences, beliefs, and attitudes concerning gun use, also noting family composition, relationships with parents, and emotionality as correlates of gun involvement and aggression. Student surveys indicated links between gun ownership and recreational use, beliefs about gun use, and…
Prediction of the interaction between a simple moving vehicle and an infinite periodically supported rail - Green's functions approach

NASA Astrophysics Data System (ADS)

Mazilu, Traian

2010-09-01

This paper herein describes the interaction between a simple moving vehicle and an infinite periodically supported rail, in order to signalise the basic features of the vehicle/track vibration behaviour in general, and wheel/rail vibration, in particular. The rail is modelled as an infinite Timoshenko beam resting on semi-sleepers via three-directional rail pads and ballast. The time-domain analysis was performed applying Green's matrix of the track method. This method allows taking into account the nonlinearities of the wheel/rail contact and the Doppler effect. The numerical analysis is dedicated to the wheel/rail response due to two types of excitation: the steady-state interaction and rail irregularities. The study points out to certain aspects regarding the parametric resonance, the amplitude-modulated vibration due to corrugation and the Doppler effect.
Ship to Shore Connector Amphibious Craft (SSC)

DTIC Science & Technology

2015-12-01

M2 .50 Caliber (12.7mm) Machine Gun ...MK19 40mm Grenade Machine Gun and M60/M240 Series 7.62mm Light Machine Gun . TBD The SSC shall provide protection to the crew and internally... Machine Gun , MK19 40mm Grenade Machine Gun and M60/M240 Series 7.62mm Light Machine Gun . Survivability (Sea-Worthiness) T=O The SSC shall be
And the survey said.... evaluating rationale for participation in gun buybacks as a tool to encourage higher yields.

PubMed

Kasper, Rebecca E; Green, Jonathan; Damle, Rachelle N; Aidlen, Jeremy; Nazarey, Pradeep; Manno, Mariann; Borer, Esther; Hirsh, Michael P

2017-02-01

Gun buyback programs represent one arm of a multipronged approach to raise awareness and education about gun safety. The city of Worcester, MA has conducted an annual gun buyback at the Police Department Headquarters since 2002. We analyzed survey responses from a voluntary, 18-question, face-to-face structured interview from December 2009 to June 2015 using descriptive statistics to determine participant demographics and motivations for participation. A total of 943 guns were collected, and 273 individuals completed surveys. The majority of participants were white males older than 55years (42.4%). Participants represented 61 zip codes across Worcester County, with 68% having prior gun safety training and 61% with weapons remaining in the home (27% of which children could potentially access). The top reasons for turning in guns were "no longer needed" (48%) and "fear of children accessing the gun" (14%). About 1 in 3 respondents knew someone injured/killed by gun violence. Almost all (96%) respondents claimed the program raised community awareness of firearm risk. The Worcester Goods for Guns Buyback has collected more than 900 guns between 2009 and 2015. The buyback removes unwanted guns from homes and raises community awareness about firearm safety. Copyright © 2017 Elsevier Inc. All rights reserved.
RF Design of the LCLS Gun

DOE Office of Scientific and Technical Information (OSTI.GOV)

Limborg-Deprey, C

Final dimensions for the LCLS RF gun are described. This gun, referred to as the LCLS gun, is a modified version of the UCLA/BNL/SLAC 1.6 cell S-Band RF gun [1], referred to as the prototype gun. The changes include a larger mode separation (15 MHz for the LCLS gun vs. 3.5 MHz for the prototype gun), a larger radius at the iris between the 2 cells, a reduced surface field on the curvature of the iris between the two cells, Z power coupling, increased cooling channels for operation at 120 Hz, dual rf feed, deformation tuning of the full cell,more » and field probes in both cells. Temporal shaping of the klystron pulse, to reduce the average power dissipated in the gun, has also been adopted. By increasing the mode separation, the amplitude of the 0-mode electric field on the cathode decreases from 10% of the peak on axis field for the prototype gun to less than 3% for the LCLS gun for the steady state fields. Beam performance is improved as shown by the PARMELA simulations. The gun should be designed to accept a future load lock system. Modifications follow the recommendations of our RF review committee [2]. Files and reference documents are compiled in Section IV.« less
Gun Violence, Mental Illness, And Laws That Prohibit Gun Possession: Evidence From Two Florida Counties.

PubMed

Swanson, Jeffrey W; Easter, Michele M; Robertson, Allison G; Swartz, Marvin S; Alanis-Hirsch, Kelly; Moseley, Daniel; Dion, Charles; Petrila, John

2016-06-01

Gun violence kills about ninety people every day in the United States, a toll measured in wasted and ruined lives and with an annual economic price tag exceeding $200 billion. Some policy makers suggest that reforming mental health care systems and improving point-of-purchase background checks to keep guns from mentally disturbed people will address the problem. Epidemiological research shows that serious mental illness contributes little to the risk of interpersonal violence but is a strong factor in suicide, which accounts for most firearm fatalities. Meanwhile, the effectiveness of gun restrictions focused on mental illness remains poorly understood. This article examines gun-related suicide and violent crime in people with serious mental illnesses, and whether legal restrictions on firearm sales to people with a history of mental health adjudication are effective in preventing gun violence. Among the study population in two large Florida counties, we found that 62 percent of violent gun crime arrests and 28 percent of gun suicides involved individuals not legally permitted to have a gun at the time. Suggested policy reforms include enacting risk-based gun removal laws and prohibiting guns from people involuntarily detained in short-term psychiatric hospitalizations. Project HOPE—The People-to-People Health Foundation, Inc.
Experimental investigation of nozzle/plume aerodynamics at hypersonic speeds

NASA Technical Reports Server (NTRS)

Bogdanoff, David W.; Cambier, Jean-Luc

1993-01-01

Work continued on the improvement of 16-Inch Shock Tunnel. This comprised studies of ways of improving driver gas ignition, an improved driver gas mixing system, an axial translation system for the driver tube, improved diaphragm materials (carbon steel vs. stainless steel), a copper liner for the part of the driven tube near the nozzle, the use of a buffer gas between the driver and driven gases, the use of N2O in the driven tube, the use of a converging driven tube, operation of the facility as a non-reflected shock tunnel and expansion tube, operation with heated hydrogen or helium driver gas, the use of detonations in the driver and the construction of an enlarged test section. Maintenance and developmental work continued on the scramjet combustor continued. New software which greatly speeds up data analysis has been written and brought on line. In particular, software which provides very rapid generation of model surface heat flux profiles has been brought on line. A considerable amount of theoretical work was performed in connection with upgrading the 16 Inch Shock Tunnel Facility. A one-dimensional Godunov code for very high velocities and any equation of state is intended to add viscous effects in studying the operation of the Shock Tunnel and also of two-stage light gas guns.

Encyclopedia of Gun Control and Gun Rights.

ERIC Educational Resources Information Center

Utter, Glenn H.

This reference volume provides information on gun control and gun rights, including resources on the debate surrounding the Second Amendment and individuals and organizations focused on gun issues, along with statutes, court cases, events, and publications surrounding this current topic. Highlighted are the important organizations and their…
76 FR 4250 - Operating Certain Railroad Tank Cars in Excess of 263,000 Pounds Gross Rail Load; Approval

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-25

... Railroad Tank Cars in Excess of 263,000 Pounds Gross Rail Load; Approval AGENCY: Federal Railroad... certain railroad tank cars in excess of 263,000 pounds gross rail load. SUMMARY: On May 14, 2010, the... to allow certain rail tank cars, transporting hazardous materials, to exceed the gross weight on rail...
49 CFR 37.79 - Purchase or lease of new rail vehicles by public entities operating rapid or light rail systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... entities operating rapid or light rail systems. 37.79 Section 37.79 Transportation Office of the Secretary... operating rapid or light rail systems. Each public entity operating a rapid or light rail system making a... system shall ensure that the vehicle is readily accessible to and usable by individuals with disabilities...
49 CFR 37.79 - Purchase or lease of new rail vehicles by public entities operating rapid or light rail systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... entities operating rapid or light rail systems. 37.79 Section 37.79 Transportation Office of the Secretary... operating rapid or light rail systems. Each public entity operating a rapid or light rail system making a... system shall ensure that the vehicle is readily accessible to and usable by individuals with disabilities...
49 CFR 37.79 - Purchase or lease of new rail vehicles by public entities operating rapid or light rail systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... entities operating rapid or light rail systems. 37.79 Section 37.79 Transportation Office of the Secretary... operating rapid or light rail systems. Each public entity operating a rapid or light rail system making a... system shall ensure that the vehicle is readily accessible to and usable by individuals with disabilities...
49 CFR 37.79 - Purchase or lease of new rail vehicles by public entities operating rapid or light rail systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... entities operating rapid or light rail systems. 37.79 Section 37.79 Transportation Office of the Secretary... operating rapid or light rail systems. Each public entity operating a rapid or light rail system making a... system shall ensure that the vehicle is readily accessible to and usable by individuals with disabilities...
49 CFR 37.79 - Purchase or lease of new rail vehicles by public entities operating rapid or light rail systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... entities operating rapid or light rail systems. 37.79 Section 37.79 Transportation Office of the Secretary... operating rapid or light rail systems. Each public entity operating a rapid or light rail system making a... system shall ensure that the vehicle is readily accessible to and usable by individuals with disabilities...
Interaction between moving tandem wheels and an infinite rail with periodic supports - Green's matrices of the track method in stationary reference frame

NASA Astrophysics Data System (ADS)

Mazilu, Traian

2017-08-01

This paper approaches the issue of the interaction between moving tandem wheels and an infinite periodically supported rail and points out at the basic characteristics in the steady-state interaction behaviour and in the interaction in the presence of the rail random irregularity. The rail is modelled as an infinite Timoshenko beam resting on supports which are discretely modelling the inertia of the sleepers and ballast and also the viscoelastic features of the rail pads, the ballast and the subgrade. Green‧s matrices of the track method in stationary reference frame were applied so as to conduct the time-domain analysis. This method allows to consider the nonlinearities of the wheel/rail contact and the Doppler effect. The study highlights certain aspects regarding the influence of the wheel base on the wheels/rail contact forces, particularly at the parametric resonance, due to the coincidence between the wheel/rail natural frequency and the passing frequency and also when the rail surface exhibits random irregularity. It has been shown that the wheel/rail dynamic behaviour is less intense when the wheel base equals integer multiple of the sleeper bay.
FY 1998 Proposed Rail Improvement Program Supplement

DOT National Transportation Integrated Search

1997-01-01

This FY 1998 Proposed Rail Improvement Program Supplement contains those rail plan amendments which have been published subsequent to the FY 1997 Proposed Rail Improvement program supplement. This document also contains the benefit/cost methodology u...
Indiana rail plan

DOT National Transportation Integrated Search

2009-07-08

The 2009 Indiana Rail Plan was developed as part of the Indiana Multimodal Freight and Mobility Plan to direct the State of Indianas future freight and passenger rail policy, provide a framework to guide future decisions regarding rail system inve...
Preliminary national rail plan.

DOT National Transportation Integrated Search

2009-10-15

The Passenger Rail Investment and Improvement Act of 2008 (PRIIA) directed the Administrator of the Federal Railroad Administration (FRA) to develop a Preliminary National Rail Plan (PNRP or Preliminary Plan) to address the rail needs of the Nation. ...
Excitation of Surface Electromagnetic Waves on Railroad Rail

DOT National Transportation Integrated Search

1978-03-31

UMTA's Office of Rail Technology research programs aim to improve urban rail transportation systems safety. This rail-transit research study attempts to develop an onboard, separate and independent obstacle-detection system--Surface Electromagnetic W...
40 CFR 63.11177 - What records must I keep?

Code of Federal Regulations, 2010 CFR

2010-07-01

....11173(e)(3)(i). (c) Documentation from the spray gun manufacturer that each spray gun with a cup... operation, you must keep the records specified in paragraphs (e) through (g) of this section, as applicable... spray gun, electrostatic application, airless spray gun, or air assisted airless spray gun, has been...
New light-gas guns for studying high-velocity impact at space velocities

NASA Astrophysics Data System (ADS)

Khristenko, Yuri F.

2017-10-01

The paper describes new light-gas guns for the high-velocity throwing of different projectiles: an upgraded two-stage light-gas powder gun and single-, two- and three-stage compressed light-gas guns. The paper also provides the schemes, pictures and characteristics of light-gas guns.
46 CFR 160.031-6 - Marking.

Code of Federal Regulations, 2010 CFR

2010-10-01

...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Line-Throwing Appliance, Shoulder Gun Type (and Equipment) § 160.031-6 Marking. (a) Gun. The gun shall be permanently and legibly marked on the barrel with the manufacturer's model or type designation of the gun, the serial number for the gun, the official Coast Guard...
46 CFR 160.031-6 - Marking.

Code of Federal Regulations, 2013 CFR

2013-10-01

...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Line-Throwing Appliance, Shoulder Gun Type (and Equipment) § 160.031-6 Marking. (a) Gun. The gun shall be permanently and legibly marked on the barrel with the manufacturer's model or type designation of the gun, the serial number for the gun, the official Coast Guard...
46 CFR 160.031-6 - Marking.

Code of Federal Regulations, 2012 CFR

2012-10-01

...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Line-Throwing Appliance, Shoulder Gun Type (and Equipment) § 160.031-6 Marking. (a) Gun. The gun shall be permanently and legibly marked on the barrel with the manufacturer's model or type designation of the gun, the serial number for the gun, the official Coast Guard...
46 CFR 160.031-6 - Marking.

Code of Federal Regulations, 2011 CFR

2011-10-01

...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Line-Throwing Appliance, Shoulder Gun Type (and Equipment) § 160.031-6 Marking. (a) Gun. The gun shall be permanently and legibly marked on the barrel with the manufacturer's model or type designation of the gun, the serial number for the gun, the official Coast Guard...
46 CFR 160.031-6 - Marking.

Code of Federal Regulations, 2014 CFR

2014-10-01

...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Line-Throwing Appliance, Shoulder Gun Type (and Equipment) § 160.031-6 Marking. (a) Gun. The gun shall be permanently and legibly marked on the barrel with the manufacturer's model or type designation of the gun, the serial number for the gun, the official Coast Guard...
Experimental Design and Analysis of M1A1 Commander/Gunner Performance during CONOPS (Continuous Operations) Using the U-COFT (Unit Conduct of Fire Trainer)

DTIC Science & Technology

1989-09-01

gun b. 7.62-mm coax manchine gun c. Commander’s weapon station caliber .50 machine gun d. M250 grenade launchers 2. Ammunition Simulation a. 105-mm...7.62-mm machine gun f. M250 smoke grenades 3. Normal Mode Simulation a. Stabilized coax machine gun b. Stabilized main gun c. Commander’s weapon d

Revisiting Pneumatic Nail Gun Trigger Recommendations.

PubMed

Albers, James; Lowe, Brian; Lipscomb, Hester; Hudock, Stephen; Dement, John; Evanoff, Bradley; Fullen, Mark; Gillen, Matt; Kaskutas, Vicki; Nolan, James; Patterson, Dennis; Platner, James; Pompeii, Lisa; Schoenfisch, Ashley

2015-03-01

Use of a pneumatic nail gun with a sequential actuation trigger (SAT) significantly diminishes the risk for acute traumatic injury compared to use of a contact actuation trigger (CAT) nail gun. A theoretically-based increased risk of work-related musculoskeletal disorders from use of a SAT nail gun, relative to CAT, appears unlikely and remains unproven. Based on current knowledge, the use of CAT nail guns cannot be justified as a safe alternative to SAT nail guns. This letter provides a perspective of ergonomists and occupational safety researchers recommending the use of the sequential actuation trigger for all nail gun tasks in the construction industry.
Does the declining lethality of gunshot injuries mask a rising epidemic of gun violence in the United States?

PubMed

Jena, Anupam B; Sun, Eric C; Prasad, Vinay

2014-07-01

Recent mass shootings in the U.S. have reignited the important public health debate concerning measures to decrease the epidemic of gun violence. Editorialists and gun lobbyists have criticized the recent focus on gun violence, arguing that gun-related homicide rates have been stable in the last decade. While true, data from the U.S. Centers for Disease Control and Prevention also demonstrate that although gun-related homicide rates were stable between 2002 and 2011, rates of violent gunshot injuries increased. These seemingly paradoxical trends may reflect the declining lethality of gunshot injuries brought about by surgical advances in the care of the patient with penetrating trauma. Focusing on gun-related homicide rates as a summary statistic of gun violence, rather than total violent gunshot injuries, can therefore misrepresent the rising epidemic of gun violence in the U.S.
Individual-level risk factors for gun victimization in a sample of probationers.

PubMed

Wells, William; Chermak, Steven

2011-07-01

Interventions aimed at preventing the important problem of gun injuries could be improved with an understanding of whether there are unique factors that place individuals at an increased risk of gun victimization. Much remains to be known about the victims of gun violence. The purpose of this article is to assess whether there are individual-level variables uniquely related to the likelihood of experiencing a gun victimization in a sample of probationers, individuals already at a heightened risk for criminal victimization. Self-report data were collected from 235 felony probationers about, for instance, gun and nongun victimization, gang involvement, and drug sales. Results show different variables are related to nongun victimization and gun victimization. In the current sample, involvement in gun crimes are linked to an increased risk of gun victimization. Violent offending and residential stability are associated with an increased chance of crime victimization.
Investigating the link between gun possession and gun assault.

PubMed

Branas, Charles C; Richmond, Therese S; Culhane, Dennis P; Ten Have, Thomas R; Wiebe, Douglas J

2009-11-01

We investigated the possible relationship between being shot in an assault and possession of a gun at the time. We enrolled 677 case participants that had been shot in an assault and 684 population-based control participants within Philadelphia, PA, from 2003 to 2006. We adjusted odds ratios for confounding variables. After adjustment, individuals in possession of a gun were 4.46 (P < .05) times more likely to be shot in an assault than those not in possession. Among gun assaults where the victim had at least some chance to resist, this adjusted odds ratio increased to 5.45 (P < .05). On average, guns did not protect those who possessed them from being shot in an assault. Although successful defensive gun uses occur each year, the probability of success may be low for civilian gun users in urban areas. Such users should reconsider their possession of guns or, at least, understand that regular possession necessitates careful safety countermeasures.
Should gun safety be taught in schools? Perspectives of teachers.

PubMed

Obeng, Cecilia

2010-08-01

Gun-related injuries and deaths among children occur at disproportionately high rates in the United States. Children who live in homes with guns are the most likely victims. This study describes teachers' views on whether gun safety should be taught to children in the preschool and elementary years. A total of 150 survey questionnaires were distributed to public and private school teachers in preschools and elementary schools in 2 counties of a Midwestern state. In total, 62% of the 102 respondents indicated that they favored the teaching of gun safety, while 13% disapproved and 25% had no opinion. Overall, 28.4% of the respondents supported the teaching of gun safety in grades pre-K (pre-kindergarten) through first grade. About 54% indicated that police or trained military personnel should do the teaching of this subject in schools, while 6.9% suggested that teachers should do the teaching. With a majority of the teachers in favor of teaching gun safety in the schools, a larger study should be conducted that explores the introduction of gun safety into the curriculum in preschool through grade 6. Such a study should evaluate the efficacy of teaching gun safety as a measure to prevent gun violence and injuries involving guns.
Implementing Domestic Violence Gun Confiscation Policy in Rural and Urban Communities: Assessing the Perceived Risk, Benefits, and Barriers.

PubMed

Lynch, Kellie R; Logan, T K

2017-07-01

The purpose of this study was to gain a deeper understanding of why communities differing in culture and resources are willing and able to implement gun confiscation as part of a protective order in the absence of a uniform statewide gun law. Specifically, the perceived risk of intimate partner homicide and gun violence, effectiveness of implementing gun confiscation, and the barriers to implementing gun confiscation were assessed. Interviews were conducted with key community professionals ( N = 133) who worked in victim services and the justice system in one urban community and four rural, under-resourced communities. Analyses revealed that professionals in the rural communities viewed the risk of intimate partner homicide and gun violence as lower, and the process of implementing gun confiscation as less effective than professionals in the urban community. In addition, urban justice system professionals, in comparison with all other professionals, reported fewer barriers to enforcing the gun confiscation police and were more likely to downplay law enforcement limitations in the community. The results have implications for developing more effective regional strategies in states that lack domestic violence gun laws as a means to increase a community's ability to enforce gun policies and initiatives.
GUN4-Porphyrin Complexes Bind the ChlH/GUN5 Subunit of Mg-Chelatase and Promote Chlorophyll Biosynthesis in Arabidopsis[W

PubMed Central

Adhikari, Neil D.; Froehlich, John E.; Strand, Deserah D.; Buck, Stephanie M.; Kramer, David M.; Larkin, Robert M.

2011-01-01

The GENOMES UNCOUPLED4 (GUN4) protein stimulates chlorophyll biosynthesis by activating Mg-chelatase, the enzyme that commits protoporphyrin IX to chlorophyll biosynthesis. This stimulation depends on GUN4 binding the ChlH subunit of Mg-chelatase and the porphyrin substrate and product of Mg-chelatase. After binding porphyrins, GUN4 associates more stably with chloroplast membranes and was proposed to promote interactions between ChlH and chloroplast membranes—the site of Mg-chelatase activity. GUN4 was also proposed to attenuate the production of reactive oxygen species (ROS) by binding and shielding light-exposed porphyrins from collisions with O2. To test these proposals, we first engineered Arabidopsis thaliana plants that express only porphyrin binding–deficient forms of GUN4. Using these transgenic plants and particular mutants, we found that the porphyrin binding activity of GUN4 and Mg-chelatase contribute to the accumulation of chlorophyll, GUN4, and Mg-chelatase subunits. Also, we found that the porphyrin binding activity of GUN4 and Mg-chelatase affect the associations of GUN4 and ChlH with chloroplast membranes and have various effects on the expression of ROS-inducible genes. Based on our findings, we conclude that ChlH and GUN4 use distinct mechanisms to associate with chloroplast membranes and that mutant alleles of GUN4 and Mg-chelatase genes cause sensitivity to intense light by a mechanism that is potentially complex. PMID:21467578
Sources of guns to dangerous people: what we learn by asking them.

PubMed

Cook, Philip J; Parker, Susan T; Pollack, Harold A

2015-10-01

Gun violence exacts a lethal toll on public health. This paper focuses on reducing access to firearms by dangerous offenders, contributing original empirical data on the gun transactions that arm offenders in Chicago. Conducted in the fall of 2013, analysis of an open-ended survey of 99 inmates of Cook County Jail focuses on a subset of violence-prone individuals with the goal of improving law enforcement actions. Among our principal findings: *Our respondents (adult offenders living in Chicago or nearby) obtain most of their guns from their social network of personal connections. Rarely is the proximate source either direct purchase from a gun store, or theft. *Only about 60% of guns in the possession of respondents were obtained by purchase or trade. Other common arrangements include sharing guns and holding guns for others. *About one in seven respondents report selling guns, but in only a few cases as a regular source of income. *Gangs continue to play some role in Chicago in organizing gun buys and in distributing guns to members as needed. *The Chicago Police Department has a considerable effect on the workings of the underground gun market through deterrence. Transactions with strangers and less-trusted associates are limited by concerns over arrest risk (if the buyer should happen to be an undercover officer or a snitch), and about being caught with a "dirty" gun (one that has been fired in a crime). Copyright © 2015 Elsevier Inc. All rights reserved.
Control of Retrograde Signaling by Rapid Turnover of GENOMES UNCOUPLED11[OPEN

PubMed Central

Chalvin, Camille; Wu, Xu Na

2018-01-01

The exchange of signals between cellular compartments coordinates development and differentiation, modulates metabolic pathways, and triggers responses to environmental conditions. The proposed central regulator of plastid-to-nucleus retrograde signaling, GENOMES UNCOUPLED1 (GUN1), is present at very low levels, which has hampered the discovery of its precise molecular function. Here, we show that the Arabidopsis (Arabidopsis thaliana) GUN1 protein accumulates to detectable levels only at very early stages of leaf development, where it functions in the regulation of chloroplast biogenesis. GUN1 mRNA is present at high levels in all tissues, but GUN1 protein undergoes rapid degradation (with an estimated half-life of ∼4 h) in all tissues where chloroplast biogenesis has been completed. The rapid turnover of GUN1 is controlled mainly by the chaperone ClpC1, suggesting degradation of GUN1 by the Clp protease. Degradation of GUN1 slows under stress conditions that alter retrograde signaling, thus ensuring that the plant has sufficient GUN1 protein. We also find that the pentatricopeptide repeat motifs of GUN1 are important determinants of GUN1 stability. Moreover, overexpression of GUN1 causes an early flowering phenotype, suggesting a function of GUN1 in developmental phase transitions beyond chloroplast biogenesis. Taken together, our results provide new insight into the regulation of GUN1 by proteolytic degradation, uncover its function in early chloroplast biogenesis, and suggest a role in developmental phase transitions. PMID:29367233
Fast Time Response Electromagnetic Disruption Mitigation Concept

DOE PAGES

Raman, R.; Jarboe, T.; Jernigan, Thomas C.; ...

2015-09-28

An important and urgent issue for ITER is predicting and controlling disruptions. Tokamaks and spherical tokamaks have the potential to disrupt. Methods to rapidly quench the discharge after an impending disruption is detected are essential to protect the vessel and internal components. The warning time for the onset of some disruptions in tokamaks could be <10 ms, which poses stringent requirements on the disruption mitigation system for reactor systems. In this proposed method, a cylindrical boron nitride projectile containing a radiative payload composed of boron, boron nitride, or beryllium particulate matter and weighing similar to 15 g is accelerated tomore » velocities on the order of 1 to 2 km/s in <2 ms in a linear rail gun accelerator. A partially fragmented capsule is then injected into the tokamak discharge in the 3- to 6-ms timescale, where the radiative payload is dispersed. The device referred to as an electromagnetic particle injector has the potential to meet the short warning timescales for which a reactor disruption mitigation system must be built. The system is fully electromagnetic, with no mechanical moving parts, which ensures high reliability after a period of long standby.« less
Transportation, social and financial impacts of light and commuter rail.

DOT National Transportation Integrated Search

2009-09-01

While transportation impacts are often masked by heavy growth in corridor traffic and latent travel demand, : modeling enables measuring the real transportation impacts of rail projects. Rail transit is both safe and : environmentally friendly. Rail ...
49 CFR 213.135 - Switches.

Code of Federal Regulations, 2010 CFR

2010-10-01

... point to the stock rail. Broken or cracked switch point rails will be subject to the requirements of... of the stock rail. (d) The heel of each switch rail shall be secure and the bolts in each heel shall...
49 CFR 213.135 - Switches.

Code of Federal Regulations, 2011 CFR

2011-10-01

... point to the stock rail. Broken or cracked switch point rails will be subject to the requirements of... of the stock rail. (d) The heel of each switch rail shall be secure and the bolts in each heel shall...
Potential scenarios of concern for high speed rail operations

DOT National Transportation Integrated Search

2011-03-16

Currently, multiple operating authorities are proposing the : introduction of high-speed rail service in the United States. : While high-speed rail service shares a number of basic : principles with conventional-speed rail service, the operational : ...
Rail Integrity Experience on the Washington Metro System

DOT National Transportation Integrated Search

2016-04-12

The Washington Metropolitan Area Transit Authority (WMATA) provides passenger rail service to the nations capital. Although the rail system carries only passenger trains, the rail integrity issues that WMATA must manage are similar to those that f...
Review of Rail Behavior Under Wheel/Rail Impact Loading

DOT National Transportation Integrated Search

1986-04-01

The report discusses several studies involving factors that significantly affect rail life, particularly wheel impact loads. Parameters that characterize the effect of wheel impact loads on rail behavior are examined in terms of system variables such...
Analysis of Lateral Rail Restraint.

DOT National Transportation Integrated Search

1983-09-01

This report deals with the analysis of lateral rail strength using the results of experimental investigations and a nonlinear rail response model. Part of the analysis involves the parametric study of the influence of track parameters on lateral rail...
Rail base corrosion and cracking prevention

DOT National Transportation Integrated Search

2014-07-01

Rail base corrosion combined with fatigue or damage can significantly reduce rail life. Studies were done to examine the relative contribution of damage, corrosion, and fatigue on rail life. The combined effects can be separated into constituent fact...
Summary Report of Working Group 2: Computation

NASA Astrophysics Data System (ADS)

Stoltz, P. H.; Tsung, R. S.

2009-01-01

The working group on computation addressed three physics areas: (i) plasma-based accelerators (laser-driven and beam-driven), (ii) high gradient structure-based accelerators, and (iii) electron beam sources and transport [1]. Highlights of the talks in these areas included new models of breakdown on the microscopic scale, new three-dimensional multipacting calculations with both finite difference and finite element codes, and detailed comparisons of new electron gun models with standard models such as PARMELA. The group also addressed two areas of advances in computation: (i) new algorithms, including simulation in a Lorentz-boosted frame that can reduce computation time orders of magnitude, and (ii) new hardware architectures, like graphics processing units and Cell processors that promise dramatic increases in computing power. Highlights of the talks in these areas included results from the first large-scale parallel finite element particle-in-cell code (PIC), many order-of-magnitude speedup of, and details of porting the VPIC code to the Roadrunner supercomputer. The working group featured two plenary talks, one by Brian Albright of Los Alamos National Laboratory on the performance of the VPIC code on the Roadrunner supercomputer, and one by David Bruhwiler of Tech-X Corporation on recent advances in computation for advanced accelerators. Highlights of the talk by Albright included the first one trillion particle simulations, a sustained performance of 0.3 petaflops, and an eight times speedup of science calculations, including back-scatter in laser-plasma interaction. Highlights of the talk by Bruhwiler included simulations of 10 GeV accelerator laser wakefield stages including external injection, new developments in electromagnetic simulations of electron guns using finite difference and finite element approaches.
Summary Report of Working Group 2: Computation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoltz, P. H.; Tsung, R. S.

2009-01-22

The working group on computation addressed three physics areas: (i) plasma-based accelerators (laser-driven and beam-driven), (ii) high gradient structure-based accelerators, and (iii) electron beam sources and transport [1]. Highlights of the talks in these areas included new models of breakdown on the microscopic scale, new three-dimensional multipacting calculations with both finite difference and finite element codes, and detailed comparisons of new electron gun models with standard models such as PARMELA. The group also addressed two areas of advances in computation: (i) new algorithms, including simulation in a Lorentz-boosted frame that can reduce computation time orders of magnitude, and (ii) newmore » hardware architectures, like graphics processing units and Cell processors that promise dramatic increases in computing power. Highlights of the talks in these areas included results from the first large-scale parallel finite element particle-in-cell code (PIC), many order-of-magnitude speedup of, and details of porting the VPIC code to the Roadrunner supercomputer. The working group featured two plenary talks, one by Brian Albright of Los Alamos National Laboratory on the performance of the VPIC code on the Roadrunner supercomputer, and one by David Bruhwiler of Tech-X Corporation on recent advances in computation for advanced accelerators. Highlights of the talk by Albright included the first one trillion particle simulations, a sustained performance of 0.3 petaflops, and an eight times speedup of science calculations, including back-scatter in laser-plasma interaction. Highlights of the talk by Bruhwiler included simulations of 10 GeV accelerator laser wakefield stages including external injection, new developments in electromagnetic simulations of electron guns using finite difference and finite element approaches.« less

Study on service performance of 880 MPa-grade and 980 MPa-grade rail steels

NASA Astrophysics Data System (ADS)

Zhu, M.; Xu, G.; Zhou, J. H.; Wang, R. M.; Gan, X. L.

2017-09-01

With the rapid development of economy in China, the requirement for railway passenger and cargo transportation becomes higher and higher. Increasing speed and developing heavy-haul transportation can effectively improve the transportation capacity of railway. The requirement for rail steels with higher ability of abrasion resistance becomes urgent. Two kinds of rails, i.e., 880 MPa-grade and 980 MPa-grade rail steels, were laid on cargo line with 500 m short radius curve. The service performances of the tested steels were continuously tracked and analyzed during operation of total 22.5 million tons loads. Macro morphology, light band width, surface hardness and profile of rails were investigated. The results show that the performance of 980 MPa-grade rail steel is superior to that of 880 MPa-grade rail steel at same circumstance. Therefore, 980 MPa-grade rail should be selected in the cargo line with small radius curve.
Greenhouse Gas Emissions Driven by the Transportation of Goods Associated with French Consumption.

PubMed

Hawkins, Troy R; Dente, Sebastien M R

2010-11-15

The transportation of goods plays a significant role in the overall greenhouse gas emissions from consumption. This study investigates the connections between French household consumption and production and transportation-related emissions throughout product supply chains. Here a two-region, environmentally extended input-output model is combined with a novel detailed, physical-unit transportation model to examine the connection between product, location of production, choice of transport mode, and greenhouse gas emissions. Total emissions associated with French household consumption are estimated to be 627 MtCO2e, or 11 tCO2e per capita. Of these, 3% are associated with the transportation of goods within France and 10% with transport of goods outside or into France. We find that most transport originating in northern Europe is by road, whereas most transport from other regions is conducted by sea and ocean transport. Rail, inland water, and air transportation play only a minor role in terms of mass, tonne-kilometers, and greenhouse gas emissions. By product, transport of coal and coke and intermediate goods make the largest contribution to overall freight transport emissions associated with French household consumption. In terms of mass, most goods are transported by road while in terms of tonne-kilometers, sea and ocean transport plays the largest role. Road transport contributes the highest share to the transport of all goods with the exceptions of coal and coke and petroleum. We examine the potential for emissions reductions associated with shifting 10% of direct imports by air freight to sea and ocean or road transport and find that the potential reductions are less than 0.03% of total emissions associated with French consumption. We also consider shifting 10% of direct imports by road transport to rail or inland water and find potential reductions on the order of 0.4−0.5% of the total or 3−4% of the freight transport emissions associated with French consumption. The greatest reductions are achieved by shifting from road transport to rail or inland water for direct imports from northern European countries. This suggests a potential environmental benefit associated with improving rail and inland water infrastructures in Europe.
Testing of the fracture resistance of rails

NASA Astrophysics Data System (ADS)

Swiderski, Zdzislaw

Various grades of rail steel as well as whole rail sections were subjected to fracture resistance tests according to the unified method. It was found that heat treatment of rails increased fracture resistance by 50 percent. However, residual stresses also had a substantial effect. Apparent durability values N(sub c) from the Wilson formula have been derived. The influence of residual stresses on rail durability is stated.
77 FR 12182 - Safety Standard for Portable Bed Rails: Final Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-29

... of ASTM F2085- 10a, comply with the following: (i) 1.4.1 Foam and inflatable bed rails need meet only...--portable bed rail constructed primarily of nonrigid materials such as fabric or foam. 3.1.11 inflatable bed..., inflatable bed rail, are terms that are now incorporated as non-rigid bed rail under new section 3.1.12 in...
49 CFR 37.81 - Purchase or lease of used rail vehicles by public entities operating rapid or light rail systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... entities operating rapid or light rail systems. 37.81 Section 37.81 Transportation Office of the Secretary... operating rapid or light rail systems. (a) Except as provided elsewhere in this section, each public entity operating a rapid or light rail system which, after August 25, 1990, purchases or leases a used rapid or...
49 CFR 37.81 - Purchase or lease of used rail vehicles by public entities operating rapid or light rail systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... entities operating rapid or light rail systems. 37.81 Section 37.81 Transportation Office of the Secretary... operating rapid or light rail systems. (a) Except as provided elsewhere in this section, each public entity operating a rapid or light rail system which, after August 25, 1990, purchases or leases a used rapid or...
49 CFR 37.81 - Purchase or lease of used rail vehicles by public entities operating rapid or light rail systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... entities operating rapid or light rail systems. 37.81 Section 37.81 Transportation Office of the Secretary... operating rapid or light rail systems. (a) Except as provided elsewhere in this section, each public entity operating a rapid or light rail system which, after August 25, 1990, purchases or leases a used rapid or...
49 CFR 37.81 - Purchase or lease of used rail vehicles by public entities operating rapid or light rail systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... entities operating rapid or light rail systems. 37.81 Section 37.81 Transportation Office of the Secretary... operating rapid or light rail systems. (a) Except as provided elsewhere in this section, each public entity operating a rapid or light rail system which, after August 25, 1990, purchases or leases a used rapid or...
49 CFR 37.81 - Purchase or lease of used rail vehicles by public entities operating rapid or light rail systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... entities operating rapid or light rail systems. 37.81 Section 37.81 Transportation Office of the Secretary... operating rapid or light rail systems. (a) Except as provided elsewhere in this section, each public entity operating a rapid or light rail system which, after August 25, 1990, purchases or leases a used rapid or...
Rail and Motor Outloading Capability Study. Fort Devens, Massachusetts,

DTIC Science & Technology

1980-03-01

AD-AI 765 MILITARY TRAFFIC MANAGEMENT COMMAND TRANSPORTATION EN-ETC FIO 15/5 RAIL AND MOTOR OUTLOADING CAPABILITY STUDY. FORT DEVENS . MASSAC-ETC(U...REPORT TE 79-4-54 RAIL AND MOTOR OUTLOADING CAPABILITY STUDY FORT DEVENS , MASSACHUSETTS Accession Far DTIC TAB March 1980 _stribution/ Av_alability...INTRODUCTION 6.. . .. . . II. ANALYSIS OF FORT DEVENS ’ RAIL OUTLOADING FACILITIES ... . . .. . .9 A. General .9.. B. Rail Facility Description
State Firearm Laws and Interstate Transfer of Guns in the USA, 2006-2016.

PubMed

Collins, Tessa; Greenberg, Rachael; Siegel, Michael; Xuan, Ziming; Rothman, Emily F; Cronin, Shea W; Hemenway, David

2018-06-01

In a cross-sectional, panel study, we examined the relationship between state firearm laws and the extent of interstate transfer of guns, as measured by the percentage of crime guns recovered in a state and traced to an in-state source (as opposed to guns recovered in a state and traced to an out-of-state source). We used 2006-2016 data on state firearm laws obtained from a search of selected state statutes and 2006-2016 crime gun trace data from the Bureau of Alcohol, Tobacco, Firearms, and Explosives. We examined the relationship between state firearm laws and interstate transfer of guns using annual data from all 50 states during the period 2006-2016 and employing a two-way fixed effects model. The primary outcome variable was the percentage of crime guns recovered in a state that could be traced to an original point of purchase within that state as opposed to another state. The main exposure variables were eight specific state firearm laws pertaining to dealer licensing, sales restrictions, background checks, registration, prohibitors for firearm purchase, and straw purchase of guns. Four laws were independently associated with a significantly lower percentage of in-state guns: a waiting period for handgun purchase, permits required for firearm purchase, prohibition of firearm possession by people convicted of a violent misdemeanor, and a requirement for relinquishment of firearms when a person becomes disqualified from owning them. States with a higher number of gun laws had a lower percentage of traced guns to in-state dealers, with each increase of one in the total number of laws associated with a decrease of 1.6 percentage points in the proportion of recovered guns that were traced to an in-state as opposed to an out-of-state source. Based on an examination of the movement patterns of guns across states, the overall observed pattern of gun flow was out of states with weak gun laws and into states with strong gun laws. These findings indicate that certain state firearm laws are associated with a lower percentage of recovered crime guns being traced to an in-state source, suggesting reduced access to guns in states with those laws.
The Domestic Arms Race.

ERIC Educational Resources Information Center

Caetano, Donald F.

1979-01-01

Discusses the relationship of familial influence, victimization, gun ownership, and attitudes toward gun control. Victims whose parents owned guns are much more likely to own guns and oppose legislation. (JMF)
Evaluating the attractiveness of a new light rail extension: Testing simple change and displacement change hypotheses

PubMed Central

Brown, Barbara B.; Tribby, Calvin P.; Tharp, Doug; Flick, Kristi; Miller, Harvey J.; Smith, Ken R.; Jensen, Wyatt

2015-01-01

Many communities in the United States have been adding new light rail to bus-predominant public transit systems. However, there is disagreement as to whether opening light rail lines attracts new ridership or merely draws ridership from existing transit users. We study a new light rail line in Salt Lake City, Utah, USA, which is part of a complete street redevelopment. We utilize a pre-test post-test control group quasi-experimental design to test two different measures of ridership change. The first measure is calculated from stops along the light rail route; the second assumes that nearby bus stops might be displaced by the rail and calculates ridership change with those stops included as baseline. Both the simple measure (transit use changes on the complete street light rail corridor) and the “displacement” measure (transit use changes in the one-quarter mile catchment areas around new light rail stops) showed significant (p < .01) and substantial (677%) increases in transit passengers compared to pre-light rail bus users. In particular, the displacement analysis discredits a common challenge that when a new light rail line opens, most passengers are simply former bus riders whose routes were canceled in favor of light rail. The study suggests that light rail services can attract additional ridership to public transit systems. In addition, although pre-post control-group designs require time and effort, this project underscores the benefits of such quasi-experimental designs in terms of the strength of the inferences that can be drawn about the impacts of new transit infrastructure and services. PMID:26543329
Evaluating the attractiveness of a new light rail extension: Testing simple change and displacement change hypotheses.

PubMed

Werner, Carol M; Brown, Barbara B; Tribby, Calvin P; Tharp, Doug; Flick, Kristi; Miller, Harvey J; Smith, Ken R; Jensen, Wyatt

2016-01-01

Many communities in the United States have been adding new light rail to bus-predominant public transit systems. However, there is disagreement as to whether opening light rail lines attracts new ridership or merely draws ridership from existing transit users. We study a new light rail line in Salt Lake City, Utah, USA, which is part of a complete street redevelopment. We utilize a pre-test post-test control group quasi-experimental design to test two different measures of ridership change. The first measure is calculated from stops along the light rail route; the second assumes that nearby bus stops might be displaced by the rail and calculates ridership change with those stops included as baseline. Both the simple measure (transit use changes on the complete street light rail corridor) and the "displacement" measure (transit use changes in the one-quarter mile catchment areas around new light rail stops) showed significant ( p < .01) and substantial (677%) increases in transit passengers compared to pre-light rail bus users. In particular, the displacement analysis discredits a common challenge that when a new light rail line opens, most passengers are simply former bus riders whose routes were canceled in favor of light rail. The study suggests that light rail services can attract additional ridership to public transit systems. In addition, although pre-post control-group designs require time and effort, this project underscores the benefits of such quasi-experimental designs in terms of the strength of the inferences that can be drawn about the impacts of new transit infrastructure and services.
Investigation into the vibration of metro bogies induced by rail corrugation

NASA Astrophysics Data System (ADS)

Ling, Liang; Li, Wei; Foo, Elbert; Wu, Lei; Wen, Zefeng; Jin, Xuesong

2017-01-01

The current research of rail corrugation mainly focuses on the mechanisms of its formation and development. Compared with the root causes and development mechanisms, the wheel-rail impacts, the fatigue failure of vehicle-track parts, and the loss of ride comfort due to rail corrugation should also be taken into account. However, the influences of rail corrugation on vehicle and track vibration, and failure of vehicle and track structural parts are barely discussed in the literature. This paper presents an experimental and numerical investigation of the structural vibration of metro bogies caused by rail corrugation. Extensive experiments are conducted to investigate the effects of short-pitch rail corrugation on the vibration accelerations of metro bogies. A dynamic model of a metro vehicle coupled with a concrete track is established to study the influence of rail corrugation on the structural vibration of metro bogies. The field test results indicate that the short-pitch rail corrugation generates strong vibrations on the axle-boxes and the bogie frames, therefore, accelerates the fatigue failure of the bogie components. The numerical results show that short-pitch rail corrugation may largely reduce the fatigue life of the coil spring, and improving the damping value of the primary vertical dampers is likely to reduce the strong vibration induced by short-pitch rail corrugation. This research systematically studies the effect of rail corrugation on the vibration of metro bogies and proposes some remedies for mitigating strong vibrations of metro bogies and reducing the incidence of failure in primary coil springs, which would be helpful in developing new metro bogies and track maintenance procedures.
Firearms in the home: parental perceptions.

PubMed

Farah, M M; Simon, H K; Kellermann, A L

1999-11-01

Each year, thousands of children are injured or killed from unintentional gunshot wounds. Discovering a gun while playing in the home places children at risk of being injured by the firearm. To determine parental firearm storage practices and parental perceptions of the behavior of their children around guns. Cross-sectional survey of parents of children from 4 to 12 years of age. A sample of 424 parents, bringing their children to one of five pediatric ambulatory care centers, were asked to complete a 20-point self-administered questionnaire at the time of their visit. A total of 400 parents (94%) completed the questionnaire; 113 parents (28%) reported keeping a firearm (most often a handgun) in the home. Firearm owners were predominantly male, 30 years of age or older, white, and married. Of the gun owners, 52% stored their firearms loaded or unlocked, and 13% kept one or more guns loaded and unlocked. Three fourths of gun-owning parents believed that their 4- to 12-year-old child could tell the difference between a toy gun and a real gun, and 23% believed that their child could be trusted with a loaded gun. Although the majority of gun-owning parents (53%) endorsed safe storage as the best firearm injury prevention strategy, 61% of parents who do not own firearms endorse not owning guns as the best way to prevent pediatric firearm injuries. A majority of gun-owning parents store their firearms loaded or unlocked, substantially underestimating the risk of injury to their children. Many firearm-owning parents trust their child with a loaded gun and believe that their young child can tell the difference between a toy gun and a real gun.
Patterns of gun deaths across US counties 1999-2013.

PubMed

Kalesan, Bindu; Galea, Sandro

2017-05-01

We examined the socio-demographic distribution of gun deaths across 3143 counties in 50 United States' states to understand the spatial patterns and correlates of high and low gun deaths. We used aggregate counts of gun deaths and population in all counties from 1999 to 2013 from the Centers for Disease Control and Prevention's Wide-ranging Online Data for Epidemiologic Research (WONDER). We characterized four levels of gun violence, as distinct levels of gun death rates of relatively safe, unsafe, violent, and extremely violent counties, based on quartiles of 15-year county-specific gun death rates per 100,000 and used negative binomial regression models allowing clustering by state to calculate incidence rate ratios and 95% confidence intervals (95% CIs). Most states had at least one violent or extremely violent county. Extremely violent gun counties were mostly rural, poor, predominantly minority, had high unemployment rate and homicide rate. Overall, homicide rate was significantly associated with gun deaths (incidence rate ratios = 1.08, 95% CI = 1.06-1.09). In relatively safe counties, this risk was 1.09 (95% CI = 1.05-1.13) and in extremely violent gun counties was 1.03 (95% CI = 1.03-1.04). There are broad differences in gun death rates across the United States representing different levels of gun death rates in each state with distinct socio-demographic profiles. Copyright © 2017 Elsevier Inc. All rights reserved.
Association Between Substance Use and Gun-Related Behaviors.

PubMed

Chen, Danhong; Wu, Li-Tzy

2016-01-01

Gun-related violence is a public health concern. This study synthesizes findings on associations between substance use and gun-related behaviors. Searches through PubMed, Embase, and PsycINFO located 66 studies published in English between 1992 and 2014. Most studies found a significant bivariate association between substance use and increased odds of gun-related behaviors. However, their association after adjustment was mixed, which could be attributed to a number of factors such as variations in definitions of substance use and gun activity, study design, sample demographics, and the specific covariates considered. Fewer studies identified a significant association between substance use and gun access/possession than other gun activities. The significant association between nonsubstance covariates (e.g., demographic covariates and other behavioral risk factors) and gun-related behaviors might have moderated the association between substance use and gun activities. Particularly, the strength of association between substance use and gun activities tended to reduce appreciably or to become nonsignificant after adjustment for mental disorders. Some studies indicated a positive association between the frequency of substance use and the odds of engaging in gun-related behaviors. Overall, the results suggest a need to consider substance use in research and prevention programs for gun-related violence. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Analysis of magnetically immersed electron guns with non-adiabatic fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pikin, Alexander; Alessi, James G.; Beebe, Edward N.

Electron diode guns, which have strongly varying magnetic or electric fields in a cathode-anode gap, were investigated in order to generate laminar electron beams with high current density using magnetically immersed guns. By creating a strongly varying radial electric field in a cathode-anode gap of the electron gun, it was demonstrated that the optical properties of the gun can be significantly altered, which allows the generation of a laminar, high-current electron beam with relatively low magnetic field on the cathode. The relatively high magnetic compression of the electron beam achieved by this method is important for producing electron beams withmore » high current density. A similar result can be obtained by inducing a strong variation of the magnetic field in a cathode-anode gap. It was observed that creating a dip in the axial magnetic field in the cathode-anode gap of an adiabatic electron gun has an optical effect similar to guns with strong variation of radial electric field. By analyzing the electron trajectories angles and presenting the results in a gun performance map different geometries of magnetically immersed electron guns with non-adiabatic fields are compared with each other and with a more traditional adiabatic electron gun. Some advantages and limitations of guns with non-adiabatic fields are outlined. In conclusion, the tests results of non-adiabatic electron gun with modified magnetic field are presented.« less
Analysis of magnetically immersed electron guns with non-adiabatic fields

DOE PAGES

Pikin, Alexander; Alessi, James G.; Beebe, Edward N.; ...

2016-11-08

Electron diode guns, which have strongly varying magnetic or electric fields in a cathode-anode gap, were investigated in order to generate laminar electron beams with high current density using magnetically immersed guns. By creating a strongly varying radial electric field in a cathode-anode gap of the electron gun, it was demonstrated that the optical properties of the gun can be significantly altered, which allows the generation of a laminar, high-current electron beam with relatively low magnetic field on the cathode. The relatively high magnetic compression of the electron beam achieved by this method is important for producing electron beams withmore » high current density. A similar result can be obtained by inducing a strong variation of the magnetic field in a cathode-anode gap. It was observed that creating a dip in the axial magnetic field in the cathode-anode gap of an adiabatic electron gun has an optical effect similar to guns with strong variation of radial electric field. By analyzing the electron trajectories angles and presenting the results in a gun performance map different geometries of magnetically immersed electron guns with non-adiabatic fields are compared with each other and with a more traditional adiabatic electron gun. Some advantages and limitations of guns with non-adiabatic fields are outlined. In conclusion, the tests results of non-adiabatic electron gun with modified magnetic field are presented.« less

Gun Theft and Crime.

PubMed

Cook, Philip J

2018-06-01

Some law enforcement officials and other observers have asserted that theft is the primary source of guns to crime. In fact, the role of theft in supplying the guns used in robbery, assault, and murder is unknown, and current evidence provides little guidance about whether an effective program to reduce gun theft would reduce gun violence. The current article analyzes publicly available national data on gun theft together with a unique data set for Chicago. The results tend to support a conclusion that stolen guns play only a minor role in crime. First, publicly available data are used to calculate that thefts are only about 1% of all gun transactions nationwide. Second, an analysis of original data from Chicago demonstrates that less than 3% of crime guns recovered by the police have been reported stolen to the Chicago Police Department (CPD). If a gun is reported stolen, there is a 20% chance that it will be recovered, usually in conjunction with an arrest for illegal carrying. Less than half of those picked up with a stolen gun have a criminal record that includes violent offenses. Third, results from surveys of convicted criminals, both nationally and in Chicago, suggest that it is rare for respondents to have stolen the gun used in their most recent crime. The data on which these results are based have various shortcomings. A research agenda is proposed that would provide more certainty about the role of theft.
Analysis of magnetically immersed electron guns with non-adiabatic fields.

PubMed

Pikin, Alexander; Alessi, James G; Beebe, Edward N; Raparia, Deepak; Ritter, John

2016-11-01

Electron diode guns, which have strongly varying magnetic or electric fields in a cathode-anode gap, were investigated in order to generate laminar electron beams with high current density using magnetically immersed guns. By creating a strongly varying radial electric field in a cathode-anode gap of the electron gun, it was demonstrated that the optical properties of the gun can be significantly altered, which allows the generation of a laminar, high-current electron beam with relatively low magnetic field on the cathode. The relatively high magnetic compression of the electron beam achieved by this method is important for producing electron beams with high current density. A similar result can be obtained by inducing a strong variation of the magnetic field in a cathode-anode gap. It was observed that creating a dip in the axial magnetic field in the cathode-anode gap of an adiabatic electron gun has an optical effect similar to guns with strong variation of radial electric field. By analyzing the electron trajectories angles and presenting the results in a gun performance map, different geometries of magnetically immersed electron guns with non-adiabatic fields are compared with each other and with a more traditional adiabatic electron gun. Some advantages and limitations of guns with non-adiabatic fields are outlined. The tests' results of a non-adiabatic electron gun with modified magnetic field are presented.
Arabidopsis genomes uncoupled 5 (GUN5) mutant reveals the involvement of Mg-chelatase H subunit in plastid-to-nucleus signal transduction

PubMed Central

Mochizuki, Nobuyoshi; Brusslan, Judy A.; Larkin, Robert; Nagatani, Akira; Chory, Joanne

2001-01-01

A plastid-derived signal plays an important role in the coordinated expression of both nuclear- and chloroplast-localized genes that encode photosynthesis-related proteins. Arabidopsis GUN (genomes uncoupled) loci have been identified as components of plastid-to-nucleus signal transduction. Unlike wild-type plants, gun mutants have nuclear Lhcb1 expression in the absence of chloroplast development. We observed a synergistic phenotype in some gun double-mutant combinations, suggesting there are at least two independent pathways in plastid-to-nucleus signal transduction. There is a reduction of chlorophyll accumulation in gun4 and gun5 mutant plants, and a gun4gun5 double mutant shows an albino phenotype. We cloned the GUN5 gene, which encodes the ChlH subunit of Mg-chelatase. We also show that gun2 and gun3 are alleles of the known photomorphogenic mutants, hy1 and hy2, which are required for phytochromobilin synthesis from heme. These findings suggest that certain perturbations of the tetrapyrrole biosynthetic pathway generate a signal from chloroplasts that causes transcriptional repression of nuclear genes encoding plastid-localized proteins. The comparison of mutant phenotypes of gun5 and another Mg-chelatase subunit (ChlI) mutant suggests a specific function for ChlH protein in the plastid-signaling pathway. PMID:11172074
Law enforcement officers' opinions about gun locks: anchors on life jackets?

PubMed Central

Coyne-Beasley, T; Johnson, R

2001-01-01

Objectives—One way law enforcement officers support firearm safety is by promoting the use of gun locks. This investigation examined law enforcement officers' willingness to use gun locks on their own guns, as well as their opinions regarding gun locks in general. Setting—Law enforcement officers from an urban agency in the southern region of the United States. Methods—Free keyed cable gun locks were distributed to all law enforcement officers in one agency who wanted one, and then an anonymous questionnaire survey was conducted about their subsequent use of, and attitudes toward, these devices. Results—About half of the 207 officers collected gun locks (n=103). Nearly three quarters (73%) completed and returned the questionnaire. Two thirds reported that they were not using the gun lock they collected (65%), and over half disagreed that gun lock use should be required (56%). Very few cited any actual or potential technical problems with the device. An important reason given for non-use of gun locks related to being able to access the weapon quickly in case of an emergency. Conclusions—The findings highlight the need for further investigation into law enforcement officers' attitudes toward gun locks, the degree to which their attitudes affect their firearm safety counseling, and the need to develop a gun safety device that can be disengaged quickly. PMID:11565984
Wheel/Rail Noise and Vibration Control

DOT National Transportation Integrated Search

1974-05-01

Reported here are the interim results of a program under the UMTA Urban Rail Supporting Technology Program to develop a basic understanding of urban transit wheel/rail noise generation for application to the evaluation and improvement of wheel/rail n...
76 FR 19914 - Safety Standard for Portable Bed Rails: Notice of Proposed Rulemaking

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-11

... constructed primarily of nonrigid materials, such as fabric or foam. An ``inflatable bed rail'' is defined as..., such as fabric or foam; Inflatable bed rail is a portable bed rail constructed primarily of nonrigid...
49 CFR 213.119 - Continuous welded rail (CWR); plan contents.

Code of Federal Regulations, 2010 CFR

2010-10-01

... following items: (i) Loose, bent, or missing joint bolts; (ii) Rail end batter or mismatch that contributes... amount and length of rail end batter or ramp on each rail end; the amount of tread mismatch; the vertical...
49 CFR 213.119 - Continuous welded rail (CWR); plan contents.

Code of Federal Regulations, 2011 CFR

2011-10-01

... following items: (i) Loose, bent, or missing joint bolts; (ii) Rail end batter or mismatch that contributes... amount and length of rail end batter or ramp on each rail end; the amount of tread mismatch; the vertical...
Analysis of Rail Transit Vehicle Dynamic Curving Performance

DOT National Transportation Integrated Search

1984-06-01

An analytical model is developed for determining the dynamic curving performance of rail transit vehicles. The dynamic wheel/rail interaction forces, vehicle suspension and body motions and track displacement are computed, as well as wheel and rail w...
Control of rolling contact fatigue on premium rails in revenue service.

DOT National Transportation Integrated Search

2014-11-01

Effective rail maintenance strategies are : essential for controlling rolling contact fatigue : (RCF) and reducing wear of rails under heavy : axle load (HAL) operations. In an effort to : optimize rail maintenance strategies in revenue : service, Tr...
Another look at the question of density and rail transit.

DOT National Transportation Integrated Search

2011-07-01

Long community discussions about rail often include whether a citys spatial distribution of : housing, employment and other trip generators is conducive to supporting rail transit. A citys : decision to construct rail transit is based on an arr...
A desire named streetcar : fantasy and fact in rail transit planning

DOT National Transportation Integrated Search

1992-06-30

The forecasts that led local officials in eight U.S. cities to advocate rail transit projects over competing, less capital-intensive options grossly overestimated rail transit ridership and underestimated rail construction costs and operating expense...
Undergraduate Certificate in Rail Transportation/Engineering.

DOT National Transportation Integrated Search

2016-05-05

A shift in the U.S. transportation environment has led to a revival in rail transport, especially in : freight rail1. In the meantime, an aging rail employee demographic presents a severe threat to : sufficient level of individuals equipped to handle...
Hazardous Materials Flow by Rail

DOT National Transportation Integrated Search

1990-03-01

The report presents a quantitative overview of the movement of hazardous materials by rail in the United States. The data used is a hazardous materials rail waybill sample developed at TSC from the 1983 Rail Waybill Sample. The report examines (1) th...
Alignment Fixtures For Vacuum-Plasma-Spray Gun

NASA Technical Reports Server (NTRS)

Woodford, William H.; Mckechnie, Timothy N.; Power, Christopher A.; Daniel, Ronald L., Jr.

1993-01-01

Fixtures for alignment of vacuum-plasma-spray guns built. Each fixture designed to fit specific gun and holds small, battery-powered laser on centerline of gun. Laser beam projects small red dot where centerline intersects surface of workpiece to be sprayed. After laser beam positioned on surface of workpiece, fixture removed from gun and spraying proceeds.
Gun Sales. Firearm Facts.

ERIC Educational Resources Information Center

Duker, Laurie, Ed.

Minimal federal regulations on firearm sales have facilitated the proliferation of guns, gun owners, and gun dealers in the United States. This fact sheet offers data on the growing number of firearm dealers, the relative ease of obtaining and keeping a license to sell guns from the Federal Bureau of Alcohol, Tobacco, and Firearms, the lack of…
Loaded: Gun involvement among opioid users.

PubMed

Stein, Michael D; Kenney, Shannon R; Anderson, Bradley J; Bailey, Genie L

2018-06-01

Despite ample research examining how alcohol use relates to gun involvement, little is known about the relationship between opioids and gun involvement. In the current study, we examined correlates of gun possession, accessibility, and related behaviors in an opioid dependent sample. Between October 2016 and April 2017, we surveyed persons entering a brief, inpatient opioid detoxification (n = 386) and 51 contemporaneous persons seeking alcohol detoxification at the same facility in Massachusetts and recorded their lifetime experiences with gun involvement. Participants averaged 33 years of age, 74% were male, 83% were White, and 64% had a history of incarceration. Opioid users had significantly higher rates of gun involvement than persons in alcohol detoxification; for example, 31.3% (vs. 3.9%) had carried a gun for protection, 45.1% (vs. 25.5%) had been threatened with a gun, and 13.8% (vs. 2.0%) had shot at another person. Among persons misusing opioids, male and non-White respondents, and those with a history of incarceration or poorer self-control reported greater gun involvement. Opioid users, both men and women, lead gun-involved lives. Copyright © 2018 Elsevier B.V. All rights reserved.
The PLX- α Project: Progress and Plans

NASA Astrophysics Data System (ADS)

Hsu, S.; Witherspoon, F. D.; Cassibry, J.; Gilmore, M.; Samulyak, R.; Stoltz, P.; PLX-α Team

2016-10-01

The Plasma Liner Experiment-ALPHA (PLX- α) project aims to demonstrate the viability of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion (PJMIF). In the past year, progress has been made in designing and testing new contoured-gap coaxial guns, 3D model development and simulations (via Eulerian and Lagrangian hydrocodes) of PLX- α-relevant plasma-liner formation/implosion via up to 60 plasma jets ( 100 kJ of liner kinetic energy), 1D semi-analytic and numerical modeling of reactor-scale PJMIF (10s of MJ of liner kinetic energy), and preparation/upgrade of the PLX facility/diagnostics. The design goal for the coaxial guns is to form plasma jets of up to initial n 2 ×1016 cm-3, mass 5 mg, Vjet 50 km/s, rjet = 4 cm, and length 10 cm. The modeling research is assessing ram-pressure amplification and Mach-number degradation during liner convergence, evolution of liner non-uniformity amplitude and mode number, and exploration of PJMIF configurations with promising 1D and 2D fusion gains. Conical multi-jet-merging and full-4 π experiments will commence in Fall, 2016 and late 2017, respectively. Supported by the ARPA-E ALPHA Program.
Optimal design of a for middle-low-speed maglev trains

NASA Astrophysics Data System (ADS)

Xiao, Song; Zhang, Kunlun; Liu, Guoqing; Jing, Yongzhi; Sykulski, Jan K.

2018-04-01

A middle-low-speed maglev train is supported by an electromagnetic force between the suspension electromagnet (EM) and the steel rail and is driven by a linear induction motor. The capability of the suspension system has a direct bearing on safety and the technical and economic performance of the train. This paper focuses on the dependence of the electromagnetic force on the structural configuration of the EM with the purpose of improving performance of a conventional EM. Finally, a novel configuration is proposed of a hybrid suspension magnet, which combines permanent magnets and coils, in order to increase the suspension force while reducing the suspension power loss.
In vivo vascular flow profiling combined with optical tweezers based blood routing

NASA Astrophysics Data System (ADS)

Meissner, Robert; Sugden, Wade W.; Siekmann, Arndt F.; Denz, Cornelia

2017-07-01

In vivo wall shear rate is quantified during zebrafish development using particle image velocimetry for biomedical diagnosis and modeling of artificial vessels. By using brightfield microscopy based high speed video tracking we can resolve single heart-beat cycles of blood flow in both space and time. Maximum blood flow velocities and wall shear rates are presented for zebrafish at two and three days post fertilization. By applying biocompatible optical tweezers as an Optical rail we present rerouting of red blood cells in vivo. With purely light-driven means we are able to compensate the lack of proper red blood cell blood flow in so far unperfused capillaries.

Theoretical performance of plasma driven railguns

NASA Astrophysics Data System (ADS)

Thio, Y. C.; McNab, I. R.; Condit, W. C.

1983-07-01

The overall efficiency of a railgun launch system is the product of efficiencies of its subsystems: prime mover, energy storage, pulse forming network, and accelerator. In this paper, the efficiency of the accelerator is examined in terms of the processes occurring in the accelerator. The principal loss mechanisms include Joule heating in the plasma, in the rails, kinetic energy of the driving plasma and magnetic energy remaining in the accelerator after projectile exit. The mass of the plasma and the atomic weight of the ionic species are important parameters in determining the energy loss in the plasma. Techniques are developed for selecting these parameters of minimize this loss.
RF Conditioning of the Photo-Cathode RF Gun at the Advanced Photon Source - NWA RF Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, T. L.; DiMonte, N.; Nassiri, A.

A new S-band Photo-cathode (PC) gun was recently installed and RF conditioned at the Advanced Photon Source (APS) Injector Test-stand (ITS) at Argonne National Lab (ANL). The APS PC gun is a LCLS type gun fabricated at SLAC [1]. The PC gun was delivered to the APS in October 2013 and installed in the APS ITS in December 2013. At ANL, we developed a new method of fast detection and mitigation of the guns internal arcs during the RF conditioning process to protect the gun from arc damage and to RF condition more efficiently. Here, we report the results ofmore » RF measurements for the PC gun and an Auto-Restart method for high power RF conditioning.« less
From gun politics to self-defense politics: a feminist critique of the great gun debate.

PubMed

Carlson, Jennifer D

2014-03-01

This article calls attention to a problematic binary produced by public debates surrounding gun rights and gun control-namely, that women must choose armed self-protection or no self-protection at all. I argue that both anti- and pro-gun discourses, drawing on and reproducing race and class privileges, use assumptions about women's physical inferiority to further their agendas. I highlight how both sides have used guns as the proxy for self-defense and conclude by calling for a shift in public discourse to focus on the broader question of the right to self-defense rather than the narrower question of gun rights.
Revisiting Pneumatic Nail Gun Trigger Recommendations

PubMed Central

Albers, James; Lipscomb, Hester; Hudock, Stephen; Dement, John; Evanoff, Bradley; Fullen, Mark; Gillen, Matt; Kaskutas, Vicki; Nolan, James; Patterson, Dennis; Platner, James; Pompeii, Lisa; Schoenfisch, Ashley

2015-01-01

Summary Use of a pneumatic nail gun with a sequential actuation trigger (SAT) significantly diminishes the risk for acute traumatic injury compared to use of a contact actuation trigger (CAT) nail gun. A theoretically-based increased risk of work-related musculoskeletal disorders from use of a SAT nail gun, relative to CAT, appears unlikely and remains unproven. Based on current knowledge, the use of CAT nail guns cannot be justified as a safe alternative to SAT nail guns. This letter provides a perspective of ergonomists and occupational safety researchers recommending the use of the sequential actuation trigger for all nail gun tasks in the construction industry. PMID:26366020
The commuter rail circulator network design problem : formulation, solution methods, and applications

DOT National Transportation Integrated Search

2007-08-01

Commuter rail is increasingly popular as a means to introduce rail transportation to metropolitan transportation systems. The long-term benefits of commuter rail include the addition of capacity to the transportation system, providing a quality commu...
On-line high-speed rail defect detection.

DOT National Transportation Integrated Search

2004-10-01

This report presents the results of phase 2 of the project On-line high-speed rail defect detection aimed at improving the reliability and the speed of current defect detection in rails. Ultrasonic guided waves, traveling in the rail running di...
Analyses of rail chill effect

DOT National Transportation Integrated Search

1998-06-01

The principles of heat transfer are applied to analyze the so-called "rail chill" effect, which refers to hear loss by conduction from a hot rail vehicle wheel through the contact area into a cold rail, the wheel having been heated by friction brakin...
Home school student visit and introduction to rail transportation and engineering.

DOT National Transportation Integrated Search

2016-06-22

This project consisted of hosting local Champaign-Urbana, Illinois home school students for a visit to : the Rail Transportation and Engineering Center (RailTEC) at the University of Illinois at Urbana- : Champaign (UIUC). Beyond visiting RailTEC, st...
49 CFR 236.711 - Bond, rail joint.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Bond, rail joint. 236.711 Section 236.711 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Bond, rail joint. A metallic connection attached to adjoining rails to insure electrical conductivity. ...
49 CFR 236.752 - Joint, rail, insulated.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Joint, rail, insulated. 236.752 Section 236.752 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Joint, rail, insulated. A joint in which electrical insulation is provided between adjoining rails. ...
Rail accelerator research at Lewis Research Center

NASA Technical Reports Server (NTRS)

Kerslake, W. R.; Cybyk, B. Z.

1982-01-01

A rail accelerator was chosen for study as an electromagnetic space propulsion device because of its simplicity and existing technology base. The results of a mission feasibility study using a large rail accelerator for direct launch of ton-size payloads from the Earth's surface to space, and the results of initial tests with a small, laboratory rail accelerator are presented. The laboratory rail accelerator has a bore of 3 by 3 mm and has accelerated 60 mg projectiles to velocities of 300 to 1000 m/s. Rail materials of Cu, W, and Mo were tested for efficiency and erosion rate.
A Big Data Analysis Approach for Rail Failure Risk Assessment.

PubMed

Jamshidi, Ali; Faghih-Roohi, Shahrzad; Hajizadeh, Siamak; Núñez, Alfredo; Babuska, Robert; Dollevoet, Rolf; Li, Zili; De Schutter, Bart

2017-08-01

Railway infrastructure monitoring is a vital task to ensure rail transportation safety. A rail failure could result in not only a considerable impact on train delays and maintenance costs, but also on safety of passengers. In this article, the aim is to assess the risk of a rail failure by analyzing a type of rail surface defect called squats that are detected automatically among the huge number of records from video cameras. We propose an image processing approach for automatic detection of squats, especially severe types that are prone to rail breaks. We measure the visual length of the squats and use them to model the failure risk. For the assessment of the rail failure risk, we estimate the probability of rail failure based on the growth of squats. Moreover, we perform severity and crack growth analyses to consider the impact of rail traffic loads on defects in three different growth scenarios. The failure risk estimations are provided for several samples of squats with different crack growth lengths on a busy rail track of the Dutch railway network. The results illustrate the practicality and efficiency of the proposed approach. © 2017 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.
Gun policy and serious mental illness: priorities for future research and policy.

PubMed

McGinty, Emma Elizabeth; Webster, Daniel W; Barry, Colleen L

2014-01-01

In response to recent mass shootings, policy makers have proposed multiple policies to prevent persons with serious mental illness from having guns. The political debate about these proposals is often uninformed by research. To address this gap, this review article summarizes the research related to gun restriction policies that focus on serious mental illness. Gun restriction policies were identified by researching the THOMAS legislative database, state legislative databases, prior review articles, and the news media. PubMed, PsycINFO, and Web of Science databases were searched for publications between 1970 and 2013 that addressed the relationship between serious mental illness and violence, the effectiveness of gun policies focused on serious mental illness, the potential for such policies to exacerbate negative public attitudes, and the potential for gun restriction policies to deter mental health treatment seeking. Limited research suggests that federal law restricting gun possession by persons with serious mental illness may prevent gun violence from this population. Promotion of policies to prevent persons with serious mental illness from having guns does not seem to exacerbate negative public attitudes toward this group. Little is known about how restricting gun possession among persons with serious mental illness affects suicide risk or mental health treatment seeking. Future studies should examine how gun restriction policies for serious mental illness affect suicide, how such policies are implemented by states, how persons with serious mental illness perceive policies that restrict their possession of guns, and how gun restriction policies influence mental health treatment seeking among persons with serious mental illness.
Improving firearm storage in Alaska native villages: a randomized trial of household gun cabinets.

PubMed

Grossman, David C; Stafford, Helen A; Koepsell, Thomas D; Hill, Ryan; Retzer, Kyla D; Jones, Ward

2012-05-01

We determined if the installation of gun cabinets improved household firearm storage practices. We used a wait list, randomized trial design with 2 groups. The "early" group received the intervention at baseline, and the "late" group received it at 12 months. Up to 2 gun cabinets were installed in each enrolled home, along with safety messages. In-person surveys were conducted at 12 and 18 months to determine the proportion of households reporting unlocked guns or ammunition. Direct observations of unlocked guns were also compared. At baseline, 93% of homes reported having at least 1 unlocked gun in the home, and 89% reported unlocked ammunition. At 12 months, 35% of homes in the early group reported unlocked guns compared with 89% in the late group (P < .001). Thirty-six percent of the early homes reported unlocked ammunition compared with 84% of late homes (P < .001). The prevalence of these storage practices was maintained at 18 months. Observations of unlocked guns decreased significantly (from 20% to 8%) between groups (P < .03). Gun cabinet installation in rural Alaskan households improved the storage of guns and ammunition. If these gains are sustained over time, it may lead to a reduction in gun-related injuries and deaths in this population.
Effects of undercover police stings of gun dealers on the supply of new guns to criminals

PubMed Central

Webster, D W; Bulzacchelli, M T; Zeoli, A M; Vernick, J S

2006-01-01

Objective To assess the effects of undercover police stings and lawsuits against gun dealers suspected of facilitating illegal gun sales in three US cities (Chicago, Detroit, Gary) on the flow of new firearms to criminals. Methods An interrupted time series design and negative binomial regression analyses were used to test for temporal change in the recovery of guns used in crimes within one year of retail sale in both intervention and comparison cities. Results The stings were associated with an abrupt 46.4% reduction in the flow of new guns to criminals in Chicago (95% confidence interval, −58.6% to −30.5%), and with a gradual reduction in new crime guns recovered in Detroit. There was no significant change associated with the stings in Gary, and no change in comparison cities that was coincident with the stings in Chicago and Detroit. Conclusions The announcement of police stings and lawsuits against suspect gun dealers appeared to have reduced the supply of new guns to criminals in Chicago significantly, and may have contributed to beneficial effects in Detroit. Given the important role that gun stores play in supplying guns to criminals in the US, further efforts of this type are warranted and should be evaluated. PMID:16887943
Survey of SRF guns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belomestnykh, S.

Developing Superconducting RF (SRF) electron guns is an active field with several laboratories working on different gun designs. While the first guns were based on elliptic cavity geometries, Quarter Wave Resonator (QWR) option is gaining popularity. QWRs are especially well suited for producing beams with high charge per bunch. In this talk we will describe recent progress in developing both types of SRF guns. SRF guns made excellent progress in the last two years. Several guns generated beams and one, at HZDR, injected beam into an accelerator. By accomplishing this, HZDR/ELBE gun demonstrated feasibility of the SRF gun concept withmore » a normal-conducting Cs{sub 2}Te cathode. The cathode demonstrated very good performance with the lifetime of {approx}1 year. However, for high average current/high bunch charge operation CsK{sub 2}Sb is preferred as it needs green lasers, unlike UV laser for the Cs{sub 2}Te, which makes it easier to build laser/optics systems. Other high QE photocathodes are being developed for SRF guns, most notably diamond-amplified photocathode. Several QWR guns are under development with one producing beam already. They are very promising for high bunch charge operation. The field is very active and we should expect more good results soon.« less
Regulation of firearm dealers in the United States: an analysis of state law and opportunities for improvement.

PubMed

Vernick, Jon S; Webster, Daniel W; Bulzacchelli, Maria T; Mair, Julie Samia

2006-01-01

Firearms were associated with 30, 136 deaths in the United States in 2003. Most guns are initially sold to the public through a network of retail dealers. Licensed firearm dealers are an important source of guns for criminals and gun traffickers. Just one percent of licensed dealers were responsible for more than half of all guns traced to crime. Federal law makes it difficult for ATF to inspect and revoke the licenses of problem gun dealers. State licensing systems, however, are a greatly under-explored opportunity for firearm dealer oversight. We identify and categorize these state systems to identify opportunities for interventions to prevent problem dealers from supplying guns to criminals, juveniles, or gun traffickers. Just seventeen states license gun dealers. Twenty-three states permit routine inspections of dealers but only two mandate that those inspections occur on a regular basis. Twenty-six states impose record-keeping requirements for gun sales. Only thirteen states require some form of store security measures to minimize firearm theft. We conclude with recommendations for a comprehensive system of state licensing and oversight of gun dealers. Our findings can be useful for the coalition of more than fifty U.S. mayors that recently announced it would work together to combat illegal gun trafficking.
Effects of anchoring and arc structure on the control authority of a rail plasma actuator

NASA Astrophysics Data System (ADS)

Choi, Young-Joon; Gray, Miles; Sirohi, Jayant; Raja, Laxminarayan L.

2017-09-01

Experiments were conducted on a rail plasma actuator (RailPAc) with different electrode cross sections (rails or rods) to assess methods to improve the actuation authority, defined as the impulse generated for a given electrical input. The arc was characterized with electrical measurements and high-speed images, while impulse measurements quantified the actuation authority. A RailPAc power supply capable of delivering ∼1 kA of current at ∼100 V was connected to rod electrodes (free-floating with circular cross-section) and rail electrodes (flush-mounted in a flat plate with rectangular cross-section). High-speed images show that the rail electrodes cause the arc to anchor itself to the anode electrode and transit in discrete jumps, while rod electrodes permit the arc to transit smoothly without anchoring. The impulse measurements reveal that the anchoring reduces the actuation authority by ∼21% compared to a smooth transit, and the effect of anchoring can be suppressed by reducing the gap between the rails to 2 mm. The study further demonstrates that if a smooth transit is achieved, the control authority can be increased with a larger gap and larger arc current. In conclusion, the actuation authority of a RailPAc can be maximized by carefully choosing a gap width that prevents anchoring. Further study is warranted to increase the RailPAc actuation authority by introducing multiple turns of wires beneath the RailPAc to augment the induced magnetic field.
A method for improved accuracy in three dimensions for determining wheel/rail contact points

NASA Astrophysics Data System (ADS)

Yang, Xinwen; Gu, Shaojie; Zhou, Shunhua; Zhou, Yu; Lian, Songliang

2015-11-01

Searching for the contact points between wheels and rails is important because these points represent the points of exerted contact forces. In order to obtain an accurate contact point and an in-depth description of the wheel/rail contact behaviours on a curved track or in a turnout, a method with improved accuracy in three dimensions is proposed to determine the contact points and the contact patches between the wheel and the rail when considering the effect of the yaw angle and the roll angle on the motion of the wheel set. The proposed method, with no need of the curve fitting of the wheel and rail profiles, can accurately, directly, and comprehensively determine the contact interface distances between the wheel and the rail. The range iteration algorithm is used to improve the computation efficiency and reduce the calculation required. The present computation method is applied for the analysis of the contact of rails of CHINA (CHN) 75 kg/m and wheel sets of wearing type tread of China's freight cars. In addition, it can be proved that the results of the proposed method are consistent with that of Kalker's program CONTACT, and the maximum deviation from the wheel/rail contact patch area of this two methods is approximately 5%. The proposed method, can also be used to investigate static wheel/rail contact. Some wheel/rail contact points and contact patch distributions are discussed and assessed, wheel and rail non-worn and worn profiles included.
Ready, Fire, Aim: The College Campus Gun Fight

ERIC Educational Resources Information Center

Birnbaum, Robert

2013-01-01

The question of whether guns should be permitted on college and university campuses in the United States reflects the tension between two competing perspectives. America has both a robust gun culture and an equally robust (if less well known) gun-control culture. The gun culture is as American as apple pie: There may be as many as 300 million…

Gun Safety Management with Patients at Risk for Suicide

ERIC Educational Resources Information Center

Simon, Robert I.

2007-01-01

Guns in the home are associated with a five-fold increase in suicide. All patients at risk for suicide must be asked if guns are available at home or easily accessible elsewhere, or if they have intent to buy or purchase a gun. Gun safety management requires a collaborative team approach including the clinician, patient, and designated person…
Universal Linear Motor Driven Leg Press Dynamometer and Concept of Serial Stretch Loading.

PubMed

Hamar, Dušan

2015-08-24

Paper deals with backgrounds and principles of universal linear motor driven leg press dynamometer and concept of serial stretch loading. The device is based on two computer controlled linear motors mounted to the horizontal rails. As the motors can keep either constant resistance force in selected position or velocity in both directions, the system allows simulation of any mode of muscle contraction. In addition, it also can generate defined serial stretch stimuli in a form of repeated force peaks. This is achieved by short segments of reversed velocity (in concentric phase) or acceleration (in eccentric phase). Such stimuli, generated at the rate of 10 Hz, have proven to be a more efficient means for the improvement of rate of the force development. This capability not only affects performance in many sports, but also plays a substantial role in prevention of falls and their consequences. Universal linear motor driven and computer controlled dynamometer with its unique feature to generate serial stretch stimuli seems to be an efficient and useful tool for enhancing strength training effects on neuromuscular function not only in athletes, but as well as in senior population and rehabilitation patients.
Midwest regional rail system : a transportation network for the 21 century : executive report

DOT National Transportation Integrated Search

2000-02-01

The Midwest Regional Rail Initiative is an ongoing effort to develop an improved and expanded passenger rail system in the Midwest. Since 1996, the Midwest Regional Rail Initiative (MWRRI) advanced from a series of service concepts, including increas...
36 CFR Appendix F to Part 1191 - Modifications Adopted by the Department of Transportation

Code of Federal Regulations, 2010 CFR

2010-07-01

... negotiate steps may have to travel compared to the general public. Modification to 406 of Appendix D 406... shall be 8 inches (205 mm) minimum above top of rail. In light rail, commuter rail, and intercity rail...
Wheel/Rail Noise Control : A Critical Evaluation

DOT National Transportation Integrated Search

1981-01-01

Noise and vibration are the major sources of environmental impact from urban rail transit operations, and is a concern for both new and existing systems. One of the primary sources of noise on rail transit systems is wheel/rail noise, or, the noise e...
Wheel/Rail Noise and Vibration : Volume 1. Mechanics of Wheel Rail Noise Generation.

DOT National Transportation Integrated Search

1975-05-01

The final reports are reported of a project to develop a basic understanding of urban transit wheel/rail noise control measures. Analytical models of impedance, response, radiation efficiency, and directivity of wheels and rails are presented and com...
75 FR 17462 - Quarterly Rail Cost Adjustment Factor

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-06

... decision may be purchased by contacting the office of Public Assistance, Governmental Affairs, and...-2)] Quarterly Rail Cost Adjustment Factor AGENCY: Surface Transportation Board. ACTION: Approval of rail cost adjustment factor. SUMMARY: The Board has approved the second quarter 2010 Rail Cost...
Rail transportation : Federal Railroad Administration's new approach to rail safety

DOT National Transportation Integrated Search

1997-07-01

In 1980, the Congress passed the Staggers Rail Act, which fostered substantial changes in the railroad industry. By 1995, fewer large freight railroads accounted for most of the industry's revenue and train miles. At the same time, these freight rail...
78 FR 57450 - State Rail Plan Guidance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-18

... development of State rail plans, as appropriate. A commenter recommended that the FRA Regional Manager be... integration of State rail plan development within the statewide/nonmetropolitan transportation planning... Guidance is to describe the processes for the development, submission, and acceptance of State rail plans...
In-Service Performance and Costs of Methods to Control Urban Rail System Noise

DOT National Transportation Integrated Search

1979-12-01

This study evaluates the acoustic and economic effectiveness of five methods of controlling wheel/rail noise and vibration on urban rail transit systems, namely: rail grinding, wheel truing, resilient wheels, ring-damped wheels, and welded vs. jointe...
Adolescent gun violence prevention: what we know, and what we can do to keep young people safe.

PubMed

Dodson, Nancy A

2016-08-01

This review will focus on recent research, initiatives, and legislation regarding the issue of gun violence as it pertains to adolescents. Homicide and suicide continue to be major killers of adolescents in the United States. Gun homicide kills teens in the most urban areas of the United States at the same rate as suicide kills teens in the most rural areas of the United States. Research on assault-injured youth sheds light on risk factors for teen gun homicide, and has found high rates of illegal gun carrying and retaliatory attitudes among at-risk teens. Suicide research continues to show a strong correlation between gun ownership and accessibility, and risk of completed suicide. Stand Your Ground laws and campus carry laws present unique threats to different populations of American teens. Given the enormous toll that gun violence takes on adolescent lives, pediatricians should ask about guns in the home and become involved in efforts to strengthen laws that would decrease gun violence.
50 CFR 92.20 - Methods and means.

Code of Federal Regulations, 2010 CFR

2010-10-01

... birds: (a) Swivel guns, shotguns larger than 10 gauge, punt guns, battery guns, machine guns, fish hooks... traditional means of harvesting auklets on Diomede and St. Lawrence islands.); (e) Hunting with the aid of...
Design and development of a 40 kV pierce electron gun

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharjee, D.; Tiwari, R.; Jayaprakash, D., E-mail: dhruva.bhattacharjee@gmail.com

A 40 kV electron gun is designed and developed using the Pierce configuration for the focusing electrode. Simulations were carried out using CST Particle Studio. The Gun is a thermionic type electron gun with indirect heating of the LaB6 cathode. The gun is capable of delivering a beam current of more than 500 mA at 40 kV with a beam size of less than 5 mm. The cathode assembly consists of cups and heat shields made out of Tantalum and Rhenium sheets. The cathode assembly and the electron gun was fabricated, assembled and tested on test bench for cathode conditioning,more » HV conditioning and beam characterization. This paper presents the gun design, particle simulations study, testing of the gun on test bench. (author)« less
Proceedings : Seminar on the use of Composite Third Rail in Electrified Transit and Commuter Rail Systems

DOT National Transportation Integrated Search

1978-11-01

The seminar was organized at the request of UMTA to disseminate accurate information on, and experience with, composite (aluminum and steel) third, or contact rail, in wayside power distribution systems of electrified urban rail properties. The semin...
Wheel/Rail Noise and Vibration : Volume 2. Applications to Control of Wheel/Rail Noise.

DOT National Transportation Integrated Search

1975-05-01

The final reports are reported of a project to develop a basic understanding of urban transit wheel/rail noise control measures. Analytical models of impedance, response, radiation efficiency, and directivity of wheels and rails are presented and com...
76 FR 59483 - Quarterly Rail Cost Adjustment Factor

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-26

... the decision may be purchased by contacting the Office of Public Assistance, Governmental Affairs, and...)] Quarterly Rail Cost Adjustment Factor AGENCY: Surface Transportation Board, DOT. ACTION: Approval of rail cost adjustment factor. SUMMARY: The Board has approved the fourth quarter 2011 Rail Cost Adjustment...
Effect of Wheel/Rail Loads on Concrete Tie Stresses and Rail Rollover.

DOT National Transportation Integrated Search

2011-09-21

As a result of vertical and lateral wheel/rail forces, high contact stresses can develop at the interface between the rail base and tie. Under certain conditions, these stresses can exceed the strength of the concrete tie and result in deterioration ...
77 FR 68722 - National Highway-Rail Crossing Inventory Reporting Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-16

...-0007, Notice No. 2] RIN 2130-AC26 National Highway-Rail Crossing Inventory Reporting Requirements... Notice of Proposed Rulemaking (NPRM) on National Highway-Rail Crossing Inventory Reporting Requirements... National Highway-Rail Crossing Inventory (Crossing Inventory). This notice announces the scheduling of the...
77 FR 48591 - State Rail Plan Guidance

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-14

... Plan Guidance AGENCY: Federal Railroad Administration (FRA), Department of Transportation (DOT). ACTION: Request for Public Comment on Proposed State Rail Plan Guidance. SUMMARY: FRA is publishing this notice to... plans. State rail plans are documents that are required under Section 303 of the Passenger Rail...
Data Analysis and Instrumentation Requirements for Evaluating Rail Joints and Rail Fasteners in Urban Track

DOT National Transportation Integrated Search

1975-02-01

Rail fasteners for concrete ties and direct fixation and bolted rail joints have been identified as key components for improving track performance. However, the lack of statistical load data limits the development of improved design criteria and eval...

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