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Sample records for air gun source

  1. 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.

  2. Phase characteristic analysis of continuous depth air-gun source wavelet

    NASA Astrophysics Data System (ADS)

    Xing, Lei; Liu, Huaishan; Zheng, Xilai; Liu, Xueqin; Zhang, Jin; Wang, Linfei; Zou, Zhihui; Xu, Yiming

    2016-10-01

    Air guns are important sources for marine seismic exploration. Far-field wavelet of air gun arrays, as a necessary parameter for pre-stack processing and source models, plays an important role during marine seismic data processing and interpretation. When an air gun fires, it generates a series of air bubbles. Similar to onshore seismic exploration, the water forms a plastic fluid near the bubble; the farther the air gun is located from the measurement, the more steady and more accurately represented the wavelet will be. In practice, hydrophones should be placed more than 100 m from the air gun; however, traditional seismic cables cannot meet this requirement. On the other hand, vertical cables provide a viable solution to this problem. This study uses a vertical cable to receive wavelets from 38 air guns and data are collected offshore Southeast Qiong, where the water depth is over 1000 m. In this study, the wavelets measured using this technique coincide very well with the simulated wavelets and can therefore represent the real shape of the wavelets. This experiment fills a technology gap in China.

  3. Understanding air-gun bubble behavior

    SciTech Connect

    Johnson, D.T. )

    1994-11-01

    An air-gun bubble behaves approximately as a spherical bubble of an ideal gas in an infinite volume of practically incompressible water. With this simplification, the equation of bubble motion and its far-field signature is more understandable than with the more exact theory commonly cited in the literature. The terms of the equation of bubble motion are explained using elementary physics and mathematics, computation of numerical results is outlined, and an example signature is shown. An air-gun bubble is analogous to a simple harmonic oscillator consisting of a mass on a spring, with an equivalent mass equal three times that of the water displaced by the bubble, and air pressure following an ideal gas law corresponding to a spring. With this understanding, one is prepared to deal with the effects of interactions among air guns and with the high-order terms and other features that must be included to model the air-gun signature of actual seismic source arrays.

  4. Pediatric air gun shot injury

    PubMed Central

    Khan, Ubaid U.; Kamal, Naglaa M.; Mirza, Shazia J.; Sherief, Laila M.

    2014-01-01

    Air guns (AGs) use air or another compressed gas to propel a projectile. Different injuries may occur in children due to their body structure, which is less-resistant with thin soft tissue coverage that can be easily penetrated by an AG shot. We present 3 cases of pediatric AG shot injury. The first-case had right lumber deep tissue penetration of AG pallet without internal damage, the second-case had a complex course of pellet into the perineum, and the third-case was shot in the left shoulder. All cases were accidentally shot. The shooters were all children, and relatives of the victims. All patients were generally stable on arrival. Two cases were operated, and one received conservative management. On follow up, no complications were noted. At first sight, AGs and air rifles may appear relatively harmless, but they are potentially lethal and children should not be allowed to play with them. PMID:25491217

  5. Pediatric air gun shot injury.

    PubMed

    Khan, Ubaid U; Kamal, Naglaa M; Mirza, Shazia J; Sherief, Laila M

    2014-12-01

    Air guns (AGs) use air or another compressed gas to propel a projectile. Different injuries may occur in children due to their body structure, which is less-resistant with thin soft tissue coverage that can be easily penetrated by an AG shot. We present 3 cases of pediatric AG shot injury. The first-case had right lumber deep tissue penetration of AG pallet without internal damage, the second-case had a complex course of pellet into the perineum, and the third-case was shot in the left shoulder. All cases were accidentally shot. The shooters were all children, and relatives of the victims. All patients were generally stable on arrival. Two cases were operated, and one received conservative management. On follow up, no complications were noted.  At first sight, AGs and air rifles may appear relatively harmless, but they are potentially lethal and children should not be allowed to play with them.  PMID:25491217

  6. Controlled-Temperature Hot-Air Gun

    NASA Technical Reports Server (NTRS)

    Munoz, M. C.

    1986-01-01

    Materials that find applications in wind tunnels first tested in laboratory. Hot-Air Gun differs from commercial units in that flow rate and temperature monitored and controlled. With typical compressed-airsupply pressure of 25 to 38 psi (170 to 260 kPa), flow rate and maximum temperature are 34 stdft3/min (0.96 stdm3/min) and 1,090 degrees F (590 degrees C), respectively. Resembling elaborate but carefully regulated hot-air gun, setup used to apply blasts of air temperatures above 1,500 degrees F (815 degrees C) to test specimens.

  7. ECR ion source with electron gun

    DOEpatents

    Xie, Z.Q.; Lyneis, C.M.

    1993-10-26

    An Advanced Electron Cyclotron Resonance ion source having an electron gun for introducing electrons into the plasma chamber of the ion source is described. The ion source has a injection enclosure and a plasma chamber tank. The plasma chamber is defined by a plurality of longitudinal magnets. The electron gun injects electrons axially into the plasma chamber such that ionization within the plasma chamber occurs in the presence of the additional electrons produced by the electron gun. The electron gun has a cathode for emitting electrons therefrom which is heated by current supplied from an AC power supply while bias potential is provided by a bias power supply. A concentric inner conductor and outer conductor carry heating current to a carbon chuck and carbon pusher which hold the cathode in place and also heat the cathode. In the Advanced Electron Cyclotron Resonance ion source, the electron gun replaces the conventional first stage used in prior electron cyclotron resonance ion generators. 5 figures.

  8. Nozzle Extension for Safety Air Gun

    NASA Technical Reports Server (NTRS)

    Zumbrun, H. N.; Croom, Delwin R., Jr.

    1986-01-01

    New nozzle-extension design overcomes problems and incorporates original commercial nozzle, retaining intrinsic safety features. Components include extension tube, length of which made to suit application; adaptor fitting, and nozzle adaptor repinned to maintain original safety features. Design moves conical airstream to end of extension to blow machine chips away from operator. Nozzle-extension modification allows safe and efficient operation of machine tools while maintaining integrity of orginial safety-air-gun design.

  9. ECR ion source with electron gun

    DOEpatents

    Xie, Zu Q.; Lyneis, Claude M.

    1993-01-01

    An Advanced Electron Cyclotron Resonance ion source (10) having an electron gun (52) for introducing electrons into the plasma chamber (18) of the ion source (10). The ion source (10) has a injection enclosure (12) and a plasma chamber tank (14). The plasma chamber (18) is defined by a plurality of longitudinal magnets (16). The electron gun (52) injects electrons axially into the plasma chamber (18) such that ionization within the plasma chamber (18) occurs in the presence of the additional electrons produced by the electron gun (52). The electron gun (52) has a cathode (116) for emitting electrons therefrom which is heated by current supplied from an AC power supply (96) while bias potential is provided by a bias power supply (118). A concentric inner conductor (60) and Outer conductor (62) carry heating current to a carbon chuck (104) and carbon pusher (114) Which hold the cathode (116) in place and also heat the cathode (16). In the Advanced Electron Cyclotron Resonance ion source (10), the electron gun (52) replaces the conventional first stage used in prior art electron cyclotron resonance ion generators.

  10. Air gun pellet injuries: the safety of MR imaging.

    PubMed

    Oliver, C; Kabala, J

    1997-04-01

    The ferromagnetism, and therefore the safety in a magnetic resonance (MR) examination, of the most widely available air gun pellets has been tested. While many are made of lead and are not ferromagnetic, some contain steel and are deflected strongly in a magnetic field. There must therefore be careful consideration before undertaking MR examinations of patients with embedded air gun pellets.

  11. Effects of Seismic Air Guns on Pallid Sturgeon and Paddlefish.

    PubMed

    Popper, Arthur N; Carlson, Thomas J; Gross, Jackson A; Hawkins, Anthony D; Zeddies, David; Powell, Lynwood; Young, John

    2016-01-01

    Pallid sturgeon and paddlefish were placed at different distances from a seismic air gun array to determine the potential effects on mortality and nonauditory body tissues from the sound from a single shot. Fish were held 7 days postexposure and then necropsied. No fish died immediately after sound exposure or over the postexposure period. Statistical analysis of injuries showed no differences between the experimental and control animals in either type or severity of injuries. There was also no difference in injuries between fish exposed closest to the source compared with those exposed furthest from the source. PMID:26611044

  12. Effects of Seismic Air Guns on Pallid Sturgeon and Paddlefish.

    PubMed

    Popper, Arthur N; Carlson, Thomas J; Gross, Jackson A; Hawkins, Anthony D; Zeddies, David; Powell, Lynwood; Young, John

    2016-01-01

    Pallid sturgeon and paddlefish were placed at different distances from a seismic air gun array to determine the potential effects on mortality and nonauditory body tissues from the sound from a single shot. Fish were held 7 days postexposure and then necropsied. No fish died immediately after sound exposure or over the postexposure period. Statistical analysis of injuries showed no differences between the experimental and control animals in either type or severity of injuries. There was also no difference in injuries between fish exposed closest to the source compared with those exposed furthest from the source.

  13. Air pollution: a smoking gun for cancer.

    PubMed

    Zhang, Wei; Qian, Chao-Nan; Zeng, Yi-Xin

    2014-04-01

    Once considered a taboo topic or stigma, cancer is the number one public health enemy in the world. Once a product of an almost untouchable industry, tobacco is indisputably recognized as a major cause of cancer and a target for anticancer efforts. With the emergence of new economic powers in the world, especially in highly populated countries such as China, air pollution has rapidly emerged as a smoking gun for cancer and has become a hot topic for public health debate because of the complex political, economic, scientific, and technologic issues surrounding the air pollution problem. This editorial and the referred articles published in this special issue of the Chinese Journal of Cancer discuss these fundamental questions. Does air pollution cause a wide spectrum of cancers? Should air pollution be considered a necessary evil accompanying economic transformation in developing countries? Is an explosion of cancer incidence coming to China and how soon will it arrive? What must be done to prevent this possible human catastrophe? Finally, the approaches for air pollution control are also discussed.

  14. The Internal Ballistics of an Air Gun

    NASA Astrophysics Data System (ADS)

    Denny, Mark

    2011-02-01

    The internal ballistics of a firearm or artillery piece considers the pellet, bullet, or shell motion while it is still inside the barrel. In general, deriving the muzzle speed of a gunpowder firearm from first principles is difficult because powder combustion is fast and it very rapidly raises the temperature of gas (generated by gunpowder deflagration, or burning), which greatly complicates the analysis. A simple case is provided by air guns, for which we can make reasonable approximations that permit a derivation of muzzle speed. It is perhaps surprising that muzzle speed depends upon barrel length (artillerymen debated this dependence for centuries, until it was established experimentally and, later, theoretically ). Here we see that a simple physical analysis, accessible to high school or freshmen undergraduate physics students, not only derives realistic muzzle speed but also shows how it depends upon barrel length.

  15. Progress on a cryogenically cooled RF gun polarized electron source

    SciTech Connect

    Fliller, R.P., III; Edwards, H.; /Fermilab

    2006-08-01

    RF guns have proven useful in multiple accelerator applications. An RF gun capable of producing polarized electrons is an attractive electron source for the ILC or an electron-ion collider. Producing such a gun has proven elusive. The NEA GaAs photocathode needed for polarized electron production is damaged by the vacuum environment in an RF gun. Electron and ion back bombardment can also damage the cathode. These problems must be mitigated before producing an RF gun polarized electron source. In this paper we report continuing efforts to improve the vacuum environment in a normal conducting RF gun by cooling it with liquid nitrogen after a high temperature vacuum bake out. We also report on a design of a cathode preparation chamber to produce bulk GaAs photocathodes for testing in such a gun. Future directions are also discussed.

  16. Air gun pellet: cardiac penetration and peripheral embolization.

    PubMed

    Işık, Onur; Engin, Çağatay; Daylan, Ahmet; Şahutoğlu, Cengiz

    2016-05-01

    Use of high-velocity air guns can to lead to serious injuries. Management options of cardiac pellet gun injuries are based on patient stability, and course and location of the pellet. Presently reported is the case of a boy who was shot with an air gun pellet. Following right ventricular entry, the pellet lodged in the left atrium and embolized to the right iliac and femoral artery. Following pellet localization, right ventricular injury was repaired, and the pellet was removed successfully. PMID:27598599

  17. Design of an electron gun for terahertz radiation source

    NASA Astrophysics Data System (ADS)

    Li, Ji; Pei, Yuan-Ji; Hu, Tong-Ning; Chen, Qu-Shan; Feng, Guang-Yao; Shang, Lei; Li, Cheng-Long

    2014-04-01

    An EC-ITC (External-Cathode Independently Tunable Cells) RF gun was employed with the aim of obtaining short-pulse bunches with high peak current for a terahertz radiation source. A gridded DC gun plays a key role as the external injecting electron source of the ITC RF gun, the performance of which determines the beam quality in the injector and transport line. In order to make the beam well compressed in the ITC RF gun, the energy of the electrons acquired from the gridded DC gun should be 15 keV at most. A proper structure of the gridded gun with double-anode is shown to overcome the strong space- charge force on the cathode, which is able to generate 6 μs beam with 4.5 A current successfully.

  18. The Development of the Linac Coherent Light Source RF Gun

    SciTech Connect

    Dowell, David H.; Jongewaard, Erik; Lewandowski, James; Limborg-Deprey, Cecile; Li, Zenghai; Schmerge, John; Vlieks, Arnold; Wang, Juwen; Xiao, Liling; /SLAC

    2008-09-24

    The Linac Coherent Light Source (LCLS) is the first x-ray laser user facility based upon a free electron laser (FEL) requiring extraordinary beam quality to saturate at 1.5 angstroms within a 100 meter undulator.[1] This new type of light source is using the last kilometer of the three kilometer linac at SLAC to accelerate the beam to an energy as high as 13.6 GeV and required a new electron gun and injector to produce a very bright beam for acceleration. At the outset of the project it was recognized that existing RF guns had the potential to produce the desired beam but none had demonstrated it. Therefore a new RF gun or at least the modification of an existing gun was necessary. The parameters listed in Table 1 illustrate the unique characteristics of LCLS which drive the requirements for the electron gun as given in Table 2. The gun beam quality needs to accommodate emittance growth as the beam is travels through approximately one kilometer of linac and two bunch compressors before reaching the undulator. These beam requirements were demonstrated during the recent commissioning runs of the LCLS injector and linac [2] due to the successful design, fabrication, testing and operation of the LCLS gun. The goal of this paper is to relate the technical background of how the gun was able to achieve and in some cases exceed these requirements by understanding and correcting the deficiencies of the prototype s-band RF photocathode gun, the BNL/SLAC/UCLA Gun III. This paper begins with a brief history and technical description of Gun III and the Gun Test Facility (GTF) at SLAC, and studies of the gun's RF and emittance compensation solenoid. The work at the GTF identified the gun and solenoid deficiencies, and helped to define the specifications for the LCLS gun. Section 1.1.5 describes the modeling used to compute and correct the gun RF fields and Section 1.1.6 describes the use of these fields in the electron beam simulations. The magnetic design and measurements of

  19. Self-contained hot-hollow cathode gun source assembly

    DOEpatents

    Zeren, Joseph D.

    1986-01-01

    A self-contained hot-hollow cathode gun source assembly for use in a vacuum chamber includes a crucible block having a hot-hollow cathode gun mounted underneath and providing a hole for the magnetic deflection of the ion/electron beam into a crucible on top the block.

  20. Self-contained hot-hollow cathode gun source assembly

    DOEpatents

    Zeren, J.D.

    1984-08-01

    A self-contained hot-hollow cathode gun source assembly for use in a vacuum chamber includes a crucible block having a hot-hollow cathode gun mounted underneath and providing a hole for the magnetic deflection of the ion/electron beam into a crucible on top the block.

  1. Development of a Model to Assess Masking Potential for Marine Mammals by the Use of Air Guns in Antarctic Waters.

    PubMed

    Wittekind, Dietrich; Tougaard, Jakob; Stilz, Peter; Dähne, Michael; Clark, Christopher W; Lucke, Klaus; von Benda-Beckmann, Sander; Ainslie, Michael A; Siebert, Ursula

    2016-01-01

    We estimated the long-range effects of air gun array noise on marine mammal communication ranges in the Southern Ocean. Air gun impulses are subject to significant distortion during propagation, potentially resulting in a quasi-continuous sound. Propagation modeling to estimate the received waveform was conducted. A leaky integrator was used as a hearing model to assess communication masking in three species due to intermittent/continuous air gun sounds. Air gun noise is most probably changing from impulse to continuous noise between 1,000 and 2,000 km from the source, leading to a reduced communication range for, e.g., blue and fin whales up to 2,000 km from the source.

  2. Development of a Model to Assess Masking Potential for Marine Mammals by the Use of Air Guns in Antarctic Waters.

    PubMed

    Wittekind, Dietrich; Tougaard, Jakob; Stilz, Peter; Dähne, Michael; Clark, Christopher W; Lucke, Klaus; von Benda-Beckmann, Sander; Ainslie, Michael A; Siebert, Ursula

    2016-01-01

    We estimated the long-range effects of air gun array noise on marine mammal communication ranges in the Southern Ocean. Air gun impulses are subject to significant distortion during propagation, potentially resulting in a quasi-continuous sound. Propagation modeling to estimate the received waveform was conducted. A leaky integrator was used as a hearing model to assess communication masking in three species due to intermittent/continuous air gun sounds. Air gun noise is most probably changing from impulse to continuous noise between 1,000 and 2,000 km from the source, leading to a reduced communication range for, e.g., blue and fin whales up to 2,000 km from the source. PMID:26611093

  3. Air gun injury with deadly aftermath--case report.

    PubMed

    Stankov, Aleksandar; Jakovski, Zlatko; Pavlovski, Goran; Muric, Nedzat; Dwork, Andrew J; Cakar, Zdravko

    2013-01-01

    In Republic of Macedonia the use of air guns is quite widespread. They are used mainly for target practice. They are regulated by the Law of Arms, where they are defined as pneumatic weapons. There is no legal limit on type or quantity of ammunition that one may possess. Our Institute performs at least 90% of the forensic autopsies in Macedonia. In this report we describe the only fatality by pneumatic weapon to come to our attention over the past 10 years. A 6-year-old girl was accidentally wounded by her brother when he and his father were trying a new air gun, a 4.5mm single shot, break barrel, spring piston air rifle manufactured in China under the brand "Westlake". She died within minutes. Autopsy showed cardiac tamponade due to penetration of the aorta. A 0.5g metal projectile, 4.5mm in diameter, with a pointed, conical shape, was recovered from the pericardial sac.

  4. Serious air gun injuries in children: update of injury statistics and presentation of five cases.

    PubMed

    Myre, L E; Black, R E

    1987-09-01

    There were over 70,000 injuries to children caused by air guns reported from 1981 to 1984. The majority of these injuries were minor; however, serious injury resulted in eight deaths. Reported injuries include corneal perforation, liver laceration, stomach and intestinal perforation, intracranial bleeding, cardiac perforation, and hemopneumothorax. Primary care physicians must be aware of the potentially serious or lethal nature of air gun injury and educate their patients accordingly. Legislation is also needed to restrict the sale of these guns, or increase the safety of air gun use. We report five cases of potentially life-threatening injury caused by air guns, three of which required emergency laparotomy. PMID:3313302

  5. First assessment of effects of air-gun seismic shooting on marine resources in the central Adriatic sea

    SciTech Connect

    La Bella, G.; Cannata, S.; Froglia, C.

    1996-11-01

    A series of investigations were carried out to test the effects of air-gun seismic shooting on main fishery resources of the Adriatic Sea during summer 1995. The energy source used for the trial was formed by one air-gun array made up by two sub-arrays consisting in 8 air-guns each developing a total volume of c.a. 2500 i{sup 3} at 2000 psi with an amplitude of 60 bar/m. The interval between two was of 25 s. The intensity was of 210 dB re 1 mPa-m/Hz. Acoustical and spectral analysis were performed simultaneously in the surveyed areas to correlate fishery and behavior observations with sound pattern of the energization. Main results were: (1) Analysis of trawl catch data evidenced no significant changes before and after the air-gun seismic profiling. (2) Echosurvey relative estimate of pelagic biomass, performed simultaneously to trawling operations, failed to evidence any significant change in the pelagic biomass subsequent to the seismic shooting. (3) Small differences were observed in the trammel net catch composition, but one single set of pre-post fishing operations could be done in the study period. (4) Similar density estimate were obtained from dredge surveys performed by an hydraulic dredger before and after air-gun seismic profiling over a clam bed in 14 in depth. (5) Video recording of captive fish, kept into cages moored on the sea bottom at 12 in depth, evidenced a Behavioral response to the approach of the sound source; but no lethal event was recorded on captive sea-bass immediately after the seismic shooting. (6) Biochemical and histological analysis were performed to verify if it is to be related to the captive condition or is somewhat consequent to the air-gun energization. These results confirm that no relevant effects are induced on fishery resources by seismic air-gun shooting.

  6. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    NASA Astrophysics Data System (ADS)

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui; Zhang, Jue; Fang, Jing

    2015-10-01

    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 solution 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.

  7. A handheld low temperature atmospheric pressure air plasma gun for nanomaterial synthesis in liquid phase

    SciTech Connect

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui; Zhang, Jue Fang, Jing

    2015-10-15

    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 solution 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.

  8. Air gun wounding and current UK laws controlling air weapons.

    PubMed

    Bruce-Chwatt, Robert Michael

    2010-04-01

    Air weapons whether rifles or pistols are, potentially, lethal weapons. The UK legislation is complex and yet little known to the public. Hunting with air weapons and the laws controlling those animals that are permitted to be shot with air weapons is even more labyrinthine due to the legal power limitations on the possession of air weapons. Still relatively freely available by mail order or on the Internet, an increasing number of deaths have been reported from the misuse of air weapons or accidental discharges. Ammunition for air weapons has become increasingly sophisticated, effective and therefore increasingly dangerous if misused, though freely available being a mere projectile without a concomitant cartridge containing a propellant and an initiator.

  9. Note: Simulation and test of a strip source electron gun.

    PubMed

    Iqbal, Munawar; Islam, G U; Misbah, I; Iqbal, O; Zhou, Z

    2014-06-01

    We present simulation and test of an indirectly heated strip source electron beam gun assembly using Stanford Linear Accelerator Center (SLAC) electron beam trajectory program. The beam is now sharply focused with 3.04 mm diameter in the post anode region at 15.9 mm. The measured emission current and emission density were 1.12 A and 1.15 A/cm(2), respectively, that corresponds to power density of 11.5 kW/cm(2), at 10 kV acceleration potential. The simulated results were compared with then and now experiments and found in agreement. The gun is without any biasing, electrostatic and magnetic fields; hence simple and inexpensive. Moreover, it is now more powerful and is useful for accelerators technology due to high emission and low emittance parameters. PMID:24985870

  10. Note: Simulation and test of a strip source electron gun

    SciTech Connect

    Iqbal, Munawar; Islam, G. U.; Misbah, I.; Iqbal, O.; Zhou, Z.

    2014-06-15

    We present simulation and test of an indirectly heated strip source electron beam gun assembly using Stanford Linear Accelerator Center (SLAC) electron beam trajectory program. The beam is now sharply focused with 3.04 mm diameter in the post anode region at 15.9 mm. The measured emission current and emission density were 1.12 A and 1.15 A/cm{sup 2}, respectively, that corresponds to power density of 11.5 kW/cm{sup 2}, at 10 kV acceleration potential. The simulated results were compared with then and now experiments and found in agreement. The gun is without any biasing, electrostatic and magnetic fields; hence simple and inexpensive. Moreover, it is now more powerful and is useful for accelerators technology due to high emission and low emittance parameters.

  11. Note: Simulation and test of a strip source electron gun

    NASA Astrophysics Data System (ADS)

    Iqbal, Munawar; Islam, G. U.; Misbah, I.; Iqbal, O.; Zhou, Z.

    2014-06-01

    We present simulation and test of an indirectly heated strip source electron beam gun assembly using Stanford Linear Accelerator Center (SLAC) electron beam trajectory program. The beam is now sharply focused with 3.04 mm diameter in the post anode region at 15.9 mm. The measured emission current and emission density were 1.12 A and 1.15 A/cm2, respectively, that corresponds to power density of 11.5 kW/cm2, at 10 kV acceleration potential. The simulated results were compared with then and now experiments and found in agreement. The gun is without any biasing, electrostatic and magnetic fields; hence simple and inexpensive. Moreover, it is now more powerful and is useful for accelerators technology due to high emission and low emittance parameters.

  12. Note: Simulation and test of a strip source electron gun.

    PubMed

    Iqbal, Munawar; Islam, G U; Misbah, I; Iqbal, O; Zhou, Z

    2014-06-01

    We present simulation and test of an indirectly heated strip source electron beam gun assembly using Stanford Linear Accelerator Center (SLAC) electron beam trajectory program. The beam is now sharply focused with 3.04 mm diameter in the post anode region at 15.9 mm. The measured emission current and emission density were 1.12 A and 1.15 A/cm(2), respectively, that corresponds to power density of 11.5 kW/cm(2), at 10 kV acceleration potential. The simulated results were compared with then and now experiments and found in agreement. The gun is without any biasing, electrostatic and magnetic fields; hence simple and inexpensive. Moreover, it is now more powerful and is useful for accelerators technology due to high emission and low emittance parameters.

  13. MODE IDENTIFICATION OF AN ARCH DAM BY A DYNAMIC AIR-GUN TEST.

    USGS Publications Warehouse

    Liu, Hsi-Ping; Fedock, Joseph J.; Fletcher, Jon B.

    1986-01-01

    Thirteen natural frequencies of a concrete arch dam (Monticello Dam near Sacramento, California) have been identified by using a dynamic testing method which employs an air gun firing in the reservoir as the excitation source. These vibrations modes are determined from the peak responses in the Fourier amplitude spectra of the free-vibration data recorded at three crest locations using three-component geophones. Comparisons of the first five natural frequencies with results obtained by forced vibration tests using rotating mass shakers show good agreement. The next eight higher-frequency modes, not previously identified, are determined from data of the present tests.

  14. 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).

  15. 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). PMID:25937592

  16. Novel piezoelectric-based energy-harvesting power sources for gun-fired munitions

    NASA Astrophysics Data System (ADS)

    Rastegar, J.; Murray, R.; Pereira, C.; Nguyen, H.-L.

    2007-04-01

    A novel class of piezoelectric-based energy-harvesting power sources is presented for gun-fired munitions and other similar applications that require very high G survivability. The power sources are designed to harvest energy from the firing acceleration as well as vibratory motion of munitions during the flight and convert it to electrical energy to power onboard electronics. The developed piezoelectric-based energy harvesting power sources produce enough electrical energy for applications such as fuzing. The power sources are designed to withstand firing accelerations in excess of 100,000 G. In certain applications such as fuzing, the developed power sources have the potential of completely eliminating the need for chemical batteries. In fuzing applications, the developed power sources have the added advantage of providing additional safety, since with such power sources the fuzing electronics are powered only after the munitions have exited the barrel and have traveled a safe distance from the weapon platform. The design of a number of prototypes, including their packaging for high G hardening, and the results of laboratory and air-gun testing are presented. Methods to increase the efficiency of such energy-harvesting power sources and minimize friction and damping losses are discussed.

  17. Impact of air gun noise on the behaviour of marine fish and squid.

    PubMed

    Fewtrell, J L; McCauley, R D

    2012-05-01

    In this study various species of captive marine fish and one species of squid were exposed to the noise from a single air gun. Six trials were conducted off the coast of Western Australia with each trial using a different noise exposure regime. Noise levels received by the animals ranged between 120 and 184 dB re 1 μPa(2).s (SEL). Behavioural observations of the fish and squid were made before, during and after air gun noise exposure. Results indicate that as air gun noise levels increase, fish respond by moving to the bottom of the water column and swimming faster in more tightly cohesive groups. Significant increases in alarm responses were observed in fish and squid to air gun noise exceeding 147-151 dB re 1 μPa SEL. An increase in the occurrence of alarm responses was also observed as noise level increased.

  18. Retained periorbital and intracranial air-gun pellets causing sclopetaria and visual loss☆

    PubMed Central

    Al-Amry, Mohammad; Al-Taweel, Hassan; Al-Enazi, Nawaf; Alrobaian, Malek; Al-Othaimeen, Saleh

    2013-01-01

    Three healthy males presented on separate occasions to the emergency room at the King Khaled Eye Specialist Hospital (KKESH) after sustaining trauma by air-gun pellets. Clinical examination indicated sclopetaria in all the cases. The foreign bodies (air-gun pellets) were imbedded in different locations (subconjunctival, intraorbital, and intracranial). All cases resulted in a profound and permanent visual loss. The management of this traumatic injury is discussed and concurs with the published literature. PMID:25278803

  19. Influence of pellet seating on the external ballistic parameters of spring-piston air guns.

    PubMed

    Werner, Ronald; Schultz, Benno; Frank, Matthias

    2016-09-01

    In firearm examiners' and forensic specialists' casework as well as in air gun proof testing, reliable measurement of the weapon's muzzle velocity is indispensable. While there are standardized and generally accepted procedures for testing the performance of air guns, the method of seating the diabolo pellets deeper into the breech of break barrel spring-piston air guns has not found its way into standardized test procedures. The influence of pellet seating on the external ballistic parameters was investigated using ten different break barrel spring-piston air guns. Test shots were performed with the diabolo pellets seated 2 mm deeper into the breech using a pellet seater. The results were then compared to reference shots with conventionally loaded diabolo pellets. Projectile velocity was measured with a high-precision redundant ballistic speed measurement system. In eight out of ten weapons, the muzzle energy increased significantly when the pellet seater was used. The average increase in kinetic energy was 31 % (range 9-96 %). To conclude, seating the pellet even slightly deeper into the breech of spring-piston air guns might significantly alter the muzzle energy. Therefore, it is strongly recommended that this effect is taken into account when accurate and reliable measurements of air gun muzzle velocity are necessary. PMID:27448569

  20. Influence of pellet seating on the external ballistic parameters of spring-piston air guns.

    PubMed

    Werner, Ronald; Schultz, Benno; Frank, Matthias

    2016-09-01

    In firearm examiners' and forensic specialists' casework as well as in air gun proof testing, reliable measurement of the weapon's muzzle velocity is indispensable. While there are standardized and generally accepted procedures for testing the performance of air guns, the method of seating the diabolo pellets deeper into the breech of break barrel spring-piston air guns has not found its way into standardized test procedures. The influence of pellet seating on the external ballistic parameters was investigated using ten different break barrel spring-piston air guns. Test shots were performed with the diabolo pellets seated 2 mm deeper into the breech using a pellet seater. The results were then compared to reference shots with conventionally loaded diabolo pellets. Projectile velocity was measured with a high-precision redundant ballistic speed measurement system. In eight out of ten weapons, the muzzle energy increased significantly when the pellet seater was used. The average increase in kinetic energy was 31 % (range 9-96 %). To conclude, seating the pellet even slightly deeper into the breech of spring-piston air guns might significantly alter the muzzle energy. Therefore, it is strongly recommended that this effect is taken into account when accurate and reliable measurements of air gun muzzle velocity are necessary.

  1. Country made scare gun vs. air gun--a comparative study of terminal ballistics using gelatine blocks.

    PubMed

    Hallikeri, Vinay R; Gouda, Hareesh S; Kadagoudar, Shivanand A

    2012-01-10

    Country made scare gun also called as bandook in the vernacular language designed with an intention of scaring away the menacing animals is not only unique and effective but also potentially lethal and has found wide spread usage in the rural parts of India. Here an attempt has been made to study the characteristic features such as physical dimensions, mechanism of action of this weapon and to compare its penetrating ability with that of air gun, whose potential lethality is a well-documented fact, using the ballistic gelatine blocks at various ranges. It is hoped that keeping the existence of such firearms in mind by the forensic experts might help to solve the unexplained and bizarre firearm injuries encountered in day to day practice.

  2. Seismic data collection from water gun and industrial background sources in the Chicago Sanitary and Ship Canal area, Illinois, 2011

    USGS Publications Warehouse

    Morrow, William S.; Carpenter, Phillip J.; Adams, Ryan F.

    2015-01-01

    The water gun is a tool adapted from deep marine geophysical surveys that is being evaluated for use as an acoustic fish deterrent to control the movement of invasive marine species. The water gun creates a seismic signal by using a compressed air discharge to move a piston rapidly within the water, resulting in an implosion. This energy pulse may be able to modify fish behavior or destroy marine life, such as the Asian carp, at some distance. The effects of this energy pulse on structures in the Chicago Sanitary and Ship Canal (CSSC), such as canal walls, shore lines, and lock structures, are not known. The potential effects of the use of a water gun on structures was identified as a concern in the CSSC and was assessed relative to existing background sources during this study. During September 2011, two water guns with piston sizes of 80 and 343 cubic inches, respectively, were tested in the CSSC at varying pressures and distances from a canal wall consisting of dolomite and dolomite setblock. Seismic data were collected during these water gun firings using geophones on land, in boreholes, and at the canal wall interface. Data were collected at varying depths in the canal water using hydrophones. Seismic data were also collected during the occurrences of barge traffic, railroad traffic located near the electric fish barrier in Lemont, and coal-loading operations at a coal power plant near the electric fish barrier. In general, energy produced by barge and railroad sources was less than energy created by the water gun. Energy levels produced by coal-loading operations at least 200 feet from geophones were approximately four times lower than energy levels measured during water gun operations.

  3. Air rifles are more than toys: BB gun-related traumatic brain injury.

    PubMed

    Klopotek, Blaine; Weibley, Richard; Chapados, Rene

    2014-12-01

    Gunshot wounds are traumatic events that emergency departments around the country treat on a daily basis. An increasing number of these wounds are being caused by air rifles that shoot ball bearings (ie, BB guns) and, although uncommon, the results can be fatal. The general public and most practitioners may not realize the damage these "toys" can inflict. This article highlights an unfortunate event involving a BB gun accidentally discharged at close range and the consequences. Data from recent and older studies are discussed regarding the firepower of these guns and their potential for injury. PMID:25486035

  4. Auditory Effects of Multiple Impulses from a Seismic Air Gun on Bottlenose Dolphins (Tursiops truncatus).

    PubMed

    Schlundt, Carolyn E; Finneran, James J; Branstetter, Brian K; Trickey, Jennifer S; Bowman, Victoria; Jenkins, Keith

    2016-01-01

    Auditory thresholds were measured in three bottlenose dolphins before and after exposure to ten impulses from a seismic air gun. Thresholds were measured using behavioral and electrophysiological methods to determine the amount of temporary threshold shift induced. The results suggest that the potential for seismic surveys using air guns to cause auditory effects on dolphins may be lower than previously predicted; however, two of the three dolphins exhibited "anticipatory" behavioral changes at the highest exposure condition that suggested they were attempting to mitigate the effects of the exposures.

  5. Explosive flux compression generators for rail gun power sources

    SciTech Connect

    Fowler, C.M.; Peterson, D.R.; Caird, R.S.; Erickson, D.J.; Freeman, B.L.; King, J.C.

    1980-01-01

    A class of explosive magnetic flux compression generators is described that has been used successfully to power rail guns. A program to increase current magnitudes and pulse lengths is outlined. Various generator loss terms are defined and plans to overcome some of them are discussed. Included are various modifications of the conventional strip generators that are more resistant to undesirable expansion of generator components from magnetic forces. Finally, an integral rail gun is discussed that has coaxial geometry. Integral rail guns utilize the rails themselves as flux compression generator elements and, under ideal conditions, are theoretically capable of driving projectiles to arbitrarily high velocities. Integral coaxial rail guns should be superior in some regards to their square bore counterparts.

  6. Antitumor action of non thermal plasma sources, DBD and Plasma Gun, alone or in combined protocols

    NASA Astrophysics Data System (ADS)

    Robert, Eric; Brullé, Laura; Vandamme, Marc; Riès, Delphine; Le Pape, Alain; Pouvesle, Jean-Michel

    2012-10-01

    The presentation deals with the assessment on two non thermal plasma sources developed and optimized for oncology applications. The first plasma source is a floating-electrode dielectric barrier discharge powered at a few hundreds of Hz which deliver air-plasma directly on the surface of cell culture medium in dishes or on the skin or organs of mice bearing cancer tumors. The second plasma source, so called Plasma Gun, is a plasma jet source triggered in noble gas, transferred in high aspect ratio and flexible capillaries, on targeting cells or tumors after plasma transfer in air through the ``plasma plume'' generated at the capillary outlet. In vitro evidence for massive cancer cell destruction and in vivo tumor activity and growth rate reductions have been measured with both plasma sources. DNA damages, cell cycle arrests and apoptosis induction were also demonstrated following the application of any of the two plasma source both in vitro and in vivo. The comparison of plasma treatment with state of the art chemotherapeutic alternatives has been performed and last but not least the benefit of combined protocols involving plasma and chemotherapeutic treatments has been evidenced for mice bearing orthotopic pancreas cancer and is under evaluation for the colon tumors.

  7. Penetrated sigmoid colon by air gun pellet could be life threatening: A case report

    PubMed Central

    Krasniqi, Avdyl S.; Hamza, Astrit R.; Zejnullahu, Valon A.; Sada, Fatos E.; Bicaj, Besnik X.

    2014-01-01

    INTRODUCTION Air and paintball guns have been in existence for over 400 year. Although serious injury or death can result from the use of such guns, previous literature has not mentioned the issue of the penetration of the sigmoid colon by an air gun pellet. PRESENTATION OF CASE We report a rare case of a 44-year-old Caucasian woman referred to abdominal surgery after an accidental small wound had occurred in the lower left abdominal quadrant that was caused by an air gun pellet. The blood and biochemical analyses were normal but the CT scan revealed the presence of a foreign body – an air gun pellet in the left iliac region of the abdomen. Clinically, during the initial 24 h significant changes were not noticed. After 42 h, however, pain and local tenderness in the lower left abdominal quadrant was expressed. A laparotomy revealed a retained pellet in the wall of the sigmoid colon and a small leak with colonic content with consecutive local peritonitis also occurred. The foreign body was removed and the opening edges in the colon were excised and closed with the primary suture. DISCUSSION The hollow organs of the digestive tract, albeit very rarely penetrated by an air gun pellet, do not typically show all signs of an acute abdomen in the early posttraumatic phase. Such injuries can lead to a pronounced infection, which may cause septic shock if not appropriately treated. CONCLUSION For correct diagnosis, a careful approach and several daily clinical observations are required. PMID:25437671

  8. Air pollution source identification

    NASA Technical Reports Server (NTRS)

    Fordyce, J. S.

    1975-01-01

    Techniques for air pollution source identification are reviewed, and some results obtained with them are evaluated. Described techniques include remote sensing from satellites and aircraft, on-site monitoring, and the use of injected tracers and pollutants themselves as tracers. The use of a large number of trace elements in ambient airborne particulate matter as a practical means of identifying sources is discussed in detail. Sampling and analysis techniques are described, and it is shown that elemental constituents can be related to specific source types such as those found in the earth's crust and those associated with specific industries. Source identification sytems are noted which utilize charged particle X-ray fluorescence analysis of original field data.

  9. The operation of the BNL/ATF gun-IV photocathode RF gun at the Advanced Photon Source.

    SciTech Connect

    Biedron, S. G.

    1999-04-20

    At the Advanced Photon Source (APS) at Argonne National Laboratory (ANL), a free-electron laser (FEL) based on the self-amplified spontaneous emission (SASE) process is nearing completion. Recently, an rf photoinjector gun system was made available to the APS by Brookhaven National Laboratory/Accelerator Test Facility (BNL/ATF). It will be used to provide the high-brightness, low-emittance, and low-energy spread electron beam required by the SASE FEL theory. A Nd:Glass laser system, capable of producing a maximum of 500 {micro}J of UV in a 1-10 ps pulse at up to a 10-Hz repetition rate, serves as the photoinjector's drive laser. Here, the design, commissioning, and integration of this gun with the APS is discussed.

  10. Two-channel telemeter for use in a 3-inch spin air gun

    NASA Astrophysics Data System (ADS)

    Allen, F.

    1981-06-01

    A special two-channel telemeter-projectile system designed and built for use in a 3-in. spin air gun is described. The system allows batteries to be tested at a far lower cost than field testing. The telemeter projectile is unusually gun rugged an reusable in a simulated artillery environment. Test-battery current and voltage is continuously monitored by subcarrier oscillators. The fuze simulator contains logic components for controlling the battery land program, rather than using steady-state loads for the full flight. This telemeter system has potential applications in remote voltage monitoring over long periods of time.

  11. Event sensing and energy-harvesting power sources for gun-fired munitions

    NASA Astrophysics Data System (ADS)

    Rastegar, J.; Murray, R.; Pereira, C.; Nguyen, H.-L.

    2009-03-01

    A novel class of piezoelectric-based event sensing and energy-harvesting power sources is presented for gunfired munitions. The power sources are designed to harvest energy from firing acceleration and vibratory motions during the flight. The piezoelectric element may be used to measure setback acceleration level, indicate the barrel exit time and impact time and force levels for fuzing purposes. The developed power sources have the added advantage of providing safety, since the fuzing electronics are powered only after the munitions have exited the barrel. The developed piezoelectric-based energy harvesting power sources produce enough electrical energy for applications such as fuzing. The power sources are designed to withstand firing accelerations in excess of 120,000 G. In certain applications such as fuzing, the developed power sources have the potential of completely eliminating the need for chemical batteries. The design of a number of prototypes, including their packaging for high G hardening, and the results of laboratory, air-gun and firing tests are presented.

  12. High Brightness Electron Guns for Next-Generation Light Sources and Accelerators

    SciTech Connect

    H. Bluem; M.D. Cole; J. Rathke; T. Schultheiss; A.M.M. Todd; I. Ben-Zvi; T. Srinivasan-Rao; P. Colestock; D.C. Nguyen; R.L. Wood; L. Young; D. Janssen; J. Lewellen; G. Neil; H.L. Phillips; J.P. Preble

    2004-07-01

    Advanced Energy Systems continues to develop advanced electron gun and injector concepts. Several of these projects have been previously described, but the progress and status of each will be updated. The project closest to completion is an all superconducting RF (SRF) gun, being developed in collaboration with the Brookhaven National Laboratory, that uses the niobium of the cavity wall itself as the photocathode material. This gun has been fabricated and will shortly be tested with beam. The cavity string for a closely-coupled DC gun and SRF cavity injector that is expected to provide beam quality sufficient for proposed ERL light sources and FELs will be assembled at the Jefferson Laboratory later this year. We are also collaboration with Los Alamos on a prototype CW normal-conducting RF gun with similar performance, that will undergo thermal testing in late 2004. Another CW SRF gun project that uses a high quantum efficiency photocathode, similar to the FZ-Rossendorf approach, has just begun. Finally, we will present the RF design and cold test results for a fully axisymmetric, ultra-high-brightness x-band RF gun.

  13. Use of a seismic air gun to reduce survival of nonnative lake trout embryos: A tool for conservation?

    USGS Publications Warehouse

    Cox, B.S.; Dux, A.M.; Quist, M.C.; Guy, C.S.

    2012-01-01

    The detrimental impacts of nonnative lake trout Salvelinus namaycush in the western USA have prompted natural resource management agencies in several states to implement lake trout suppression programs. Currently, these programs rely on mechanical removal methods (i.e., gill nets, trap nets, and angling) to capture subadult and adult lake trout. We conducted a study to explore the potential for using high-intensity sound from a relatively small (655.5 cm3 [40 in3]) seismic air gun to reduce survival of lake trout embryos. Lake trout embryos at multiple stages of development were exposed to a single discharge of the seismic air gun at two depths (5 and 15 m) and at two distances from the air gun (0.1 and 2.7 m). Control groups for each developmental stage, distance, and depth were treated identically except that the air gun was not discharged. Mortality in lake trout embryos treated at 0.1 m from the air gun was 100% at 74 daily temperature units in degrees Celsius (TU°C) at both depths. Median mortality in lake trout embryos treated at 0.1 m from the air gun at 207 TU°C (93%) and 267 °C (78%) appeared to be higher than that of controls (49% and 48%, respectively) at 15-m depth. Among the four lake trout developmental stages, exposure to the air gun at 0.1 m resulted in acute mortality up to 60% greater than that of controls. Mortality at a distance of 2.7 m did not appear to differ from that of controls at any developmental stage or at either depth. Our results indicate that seismic air guns have potential as an alternative tool for controlling nonnative lake trout, but further investigation is warranted.

  14. Development of ion source with a washer gun for pulsed neutral beam injection.

    PubMed

    Asai, T; Yamaguchi, N; Kajiya, H; Takahashi, T; Imanaka, H; Takase, Y; Ono, Y; Sato, K N

    2008-06-01

    A new type of economical neutral beam source has been developed by using a single washer gun, pulsed operation, and a simple electrode system. We replaced the conventional hot filaments for arc-discharge-type plasma formation with a single stainless-steel washer gun, eliminating the entire dc power supply for the filaments and the cooling system for the electrodes. Our initial experiments revealed successful beam extraction up to 10 kV and 8.6 A, based on spatial profile measurements of density and temperature in the plasma source. The system also shows the potential to control the beam profile by controlling the plasma parameters in the ion accumulation chamber.

  15. Quantifying the uncertainty of geoacoustic parameter estimates for the New Jersey shelf by inverting air gun data.

    PubMed

    Jiang, Yong-Min; Chapman, N Ross; Badiey, Mohsen

    2007-04-01

    This paper describes geoacoustic inversion of low frequency air gun data acquired during an experiment on the New Jersey shelf. Hybrid optimization and Bayesian inversion techniques based on matched field processing were applied to multiple shots from three air gun data sets recorded by a vertical line array in a long-range shallow water geometry. For the Bayesian inversions, full data error covariance matrix was estimated from a set of consecutive shots that had high temporal coherence and small spatial variation in source position. The effect of different data error information on the geoacoustic parameter uncertainty estimates was investigated by using the full data error covariance matrix, a diagonalized version of the full error covariance, and a diagonal matrix with identical variances. The comparison demonstrated that inversion using the full data error information provided the most reliable parameter uncertainty estimates. The inversions were highly sensitive to the near sea floor geoacoustic parameters, including sediment attenuation, of a simple single-layer geoacoustic model. The estimated parameter values of the model were consistent with depth averaged values (over wavelength scales) of a high resolution geoacoustic model developed from extensive ground truth information. The interpretation of the frequency dependence of the estimated attenuation is also discussed. PMID:17471704

  16. Air pollution source identification

    NASA Technical Reports Server (NTRS)

    Fordyce, J. S.

    1975-01-01

    The techniques available for source identification are reviewed: remote sensing, injected tracers, and pollutants themselves as tracers. The use of the large number of trace elements in the ambient airborne particulate matter as a practical means of identifying sources is discussed. Trace constituents are determined by sensitive, inexpensive, nondestructive, multielement analytical methods such as instrumental neutron activation and charged particle X-ray fluorescence. The application to a large data set of pairwise correlation, the more advanced pattern recognition-cluster analysis approach with and without training sets, enrichment factors, and pollutant concentration rose displays for each element is described. It is shown that elemental constituents are related to specific source types: earth crustal, automotive, metallurgical, and more specific industries. A field-ready source identification system based on time and wind direction resolved sampling is described.

  17. A piloted simulation investigation of yaw dynamics requirements for turreted gun use in low-level helicopter air combat

    NASA Technical Reports Server (NTRS)

    Decker, William A.; Morris, Patrick M.; Williams, Jeffrey N.

    1988-01-01

    A piloted, fixed-base simulation study was conducted to investigate the handling qualities requirements for helicopter air-to-air combat using turreted guns in the near-terrain environment. The study used a version of the helicopter air combat system developed at NASA Ames Research Center for one-on-one air combat. The study focused on the potential trade-off between gun angular movement capability and required yaw axis response. Experimental variables included yaw axis response frequency and damping and the size of the gun-movement envelope. A helmet position and sighting system was used for pilot control of gun aim. Approximately 340 simulated air combat engagements were evaluated by pilots from the Army and industry. Results from the experiment indicate that a highly-damped, high frequency yaw response was desired for Level I handling qualities. Pilot preference for those characteristics became more pronounced as gun turret movement was restricted; however, a stable, slow-reacting platform could be used with a large turret envelope. Most pilots preferred to engage with the opponent near the own-ship centerline. Turret elevation restriction affected the engagement more than azimuth restrictions.

  18. Development of ion source with a washer gun for pulsed neutral beam injection.

    PubMed

    Asai, T; Yamaguchi, N; Kajiya, H; Takahashi, T; Imanaka, H; Takase, Y; Ono, Y; Sato, K N

    2008-06-01

    A new type of economical neutral beam source has been developed by using a single washer gun, pulsed operation, and a simple electrode system. We replaced the conventional hot filaments for arc-discharge-type plasma formation with a single stainless-steel washer gun, eliminating the entire dc power supply for the filaments and the cooling system for the electrodes. Our initial experiments revealed successful beam extraction up to 10 kV and 8.6 A, based on spatial profile measurements of density and temperature in the plasma source. The system also shows the potential to control the beam profile by controlling the plasma parameters in the ion accumulation chamber. PMID:18601403

  19. Experimental effect of shots caused by projectiles fired from air guns with kinetic energy below 17 J.

    PubMed

    Smędra-Kaźmirska, Anna; Barzdo, Maciej; Kędzierski, Maciej; Antoszczyk, Łukasz; Szram, Stefan; Berent, Jarosław

    2013-09-01

    Pursuant to the Polish Weapons and Ammunitions Law (Legal Gazette No 53/1999 item 549 with subsequent amendments), air guns with kinetic energy of the fired projectiles below 17 J are not regarded as weapons. The aim of the study was to assess the potential effect of shots caused by projectiles of various mass and structure fired from air guns with kinetic energy below 17 J on human soft tissues. As a model of soft tissue, we used 20% gelatin blocks. After shooting, we measured the depth of gelatin block penetration by pellets fired from various distances and compared these results with autopsy findings. The results demonstrated that examined pneumatic guns may cause serious injuries, including damage to the pleura, pericardium, liver, spleen, kidneys, femoral artery, and thoracic and abdominal aorta. Experiment shown that gelatin blocks do not reflect fully the properties of the human body.

  20. Experimental effect of shots caused by projectiles fired from air guns with kinetic energy below 17 J.

    PubMed

    Smędra-Kaźmirska, Anna; Barzdo, Maciej; Kędzierski, Maciej; Antoszczyk, Łukasz; Szram, Stefan; Berent, Jarosław

    2013-09-01

    Pursuant to the Polish Weapons and Ammunitions Law (Legal Gazette No 53/1999 item 549 with subsequent amendments), air guns with kinetic energy of the fired projectiles below 17 J are not regarded as weapons. The aim of the study was to assess the potential effect of shots caused by projectiles of various mass and structure fired from air guns with kinetic energy below 17 J on human soft tissues. As a model of soft tissue, we used 20% gelatin blocks. After shooting, we measured the depth of gelatin block penetration by pellets fired from various distances and compared these results with autopsy findings. The results demonstrated that examined pneumatic guns may cause serious injuries, including damage to the pleura, pericardium, liver, spleen, kidneys, femoral artery, and thoracic and abdominal aorta. Experiment shown that gelatin blocks do not reflect fully the properties of the human body. PMID:23919403

  1. Counter-facing plasma guns for efficient extreme ultra-violet plasma light source

    NASA Astrophysics Data System (ADS)

    Kuroda, Yusuke; Yamamoto, Akiko; Kuwabara, Hajime; Nakajima, Mitsuo; Kawamura, Tohru; Horioka, Kazuhiko

    2013-11-01

    A plasma focus system composed of a pair of counter-facing coaxial guns was proposed as a long-pulse and/or repetitive high energy density plasma source. We applied Li as the source of plasma for improvement of the conversion efficiency, the spectral purity, and the repetition capability. For operation of the system with ideal counter-facing plasma focus mode, we changed the system from simple coaxial geometry to a multi-channel configuration. We applied a laser trigger to make synchronous multi-channel discharges with low jitter. The results indicated that the configuration is promising to make a high energy density plasma with high spectral efficiency.

  2. Identification of Noise Sources and Design of Noise Reduction Measures for a Pneumatic Nail Gun

    PubMed Central

    Jayakumar, Vignesh; Zechmann, Edward

    2015-01-01

    An experimental-analytical procedure was implemented to reduce the operating noise level of a nail gun, a commonly found power tool in a construction site. The procedure is comprised of preliminary measurements, identification and ranking of major noise sources and application of noise controls. Preliminary measurements show that the impact noise transmitted through the structure and the exhaust related noise were found to be the first and second major contributors. Applying a noise absorbing foam on the outside of the nail gun body was found to be an effective noise reduction technique. One and two-volume small mufflers were designed and applied to the exhaust side of the nail gun which reduced not only the exhaust noise but also the impact noise. It was shown that the overall noise level could be reduced by as much as 3.5 dB, suggesting that significant noise reduction is possible in construction power tools without any significant increase of the cost. PMID:26366038

  3. Entrapment of an air gun pellet between the thyroid cartilage and the lining mucosa in a patient with a penetrating neck injury: a case report

    PubMed Central

    2012-01-01

    Introduction Air guns, either modern or traditional models, are powerful weapons that are capable of causing serious or life-threatening injuries. Case presentation Here, we present a case of an air gun pellet injury, with the pellet trapped between the thyroid cartilage and the lining mucosa of a 58-year-old Iranian man. Conclusion Entrapment of air gun pellet between thyroid cartilage and the lining mucosa, as presented in our case, may cause diagnostic challenges through the clinical presentation of slight odynophagia. PMID:22759623

  4. Piezoelectric energy-harvesting power source and event detection sensors for gun-fired munitions

    NASA Astrophysics Data System (ADS)

    Rastegar, Jahangir; Feng, Dake; Pereira, Carlos M.

    2015-05-01

    This paper presents a review of piezoelectric based energy harvesting devices and their charge collection electronics for use in very harsh environment of gun-fired munitions. A number of novel classes of such energy harvesting power sources have been developed for gun-fired munitions and similar applications, including those with integrated safety and firing setback event detection electronics and logic circuitry. The power sources are designed to harvest energy from firing acceleration and vibratory motions during the flight. As an example, the application of the developed piezoelectric based energy harvesting devices with event detection circuitry for the development of self-powered initiators with full no-fire safety circuitry for protection against accidental drops, transportation vibration, and other similar low amplitude accelerations and/or high amplitude but short duration acceleration events is presented. The design allows the use of a very small piezoelectric element, thereby allowing such devices to be highly miniaturized. These devices can be readily hardened to withstand very high G firing setback accelerations in excess of 100,000 G and the harsh firing environment. The design of prototypes and testing under realistic conditions are presented.

  5. Simulation and optimization of a 10 A electron gun with electrostatic compression for the electron beam ion source.

    PubMed

    Pikin, A; Beebe, E N; Raparia, D

    2013-03-01

    Increasing the current density of the electron beam in the ion trap of the Electron Beam Ion Source (EBIS) in BNL's Relativistic Heavy Ion Collider facility would confer several essential benefits. They include increasing the ions' charge states, and therefore, the ions' energy out of the Booster for NASA applications, reducing the influx of residual ions in the ion trap, lowering the average power load on the electron collector, and possibly also reducing the emittance of the extracted ion beam. Here, we discuss our findings from a computer simulation of an electron gun with electrostatic compression for electron current up to 10 A that can deliver a high-current-density electron beam for EBIS. The magnetic field in the cathode-anode gap is formed with a magnetic shield surrounding the gun electrodes and the residual magnetic field on the cathode is (5 ÷ 6) Gs. It was demonstrated that for optimized gun geometry within the electron beam current range of (0.5 ÷ 10) A the amplitude of radial beam oscillations can be maintained close to 4% of the beam radius by adjusting the injection magnetic field generated by a separate magnetic coil. Simulating the performance of the gun by varying geometrical parameters indicated that the original gun model is close to optimum and the requirements to the precision of positioning the gun elements can be easily met with conventional technology.

  6. Simulation and optimization of a 10 A electron gun with electrostatic compression for the electron beam ion source

    SciTech Connect

    Pikin, A.; Beebe, E. N.; Raparia, D.

    2013-03-15

    Increasing the current density of the electron beam in the ion trap of the Electron Beam Ion Source (EBIS) in BNL's Relativistic Heavy Ion Collider facility would confer several essential benefits. They include increasing the ions' charge states, and therefore, the ions' energy out of the Booster for NASA applications, reducing the influx of residual ions in the ion trap, lowering the average power load on the electron collector, and possibly also reducing the emittance of the extracted ion beam. Here, we discuss our findings from a computer simulation of an electron gun with electrostatic compression for electron current up to 10 A that can deliver a high-current-density electron beam for EBIS. The magnetic field in the cathode-anode gap is formed with a magnetic shield surrounding the gun electrodes and the residual magnetic field on the cathode is (5 Division-Sign 6) Gs. It was demonstrated that for optimized gun geometry within the electron beam current range of (0.5 Division-Sign 10) A the amplitude of radial beam oscillations can be maintained close to 4% of the beam radius by adjusting the injection magnetic field generated by a separate magnetic coil. Simulating the performance of the gun by varying geometrical parameters indicated that the original gun model is close to optimum and the requirements to the precision of positioning the gun elements can be easily met with conventional technology.

  7. Crime, Culture Conflict, and the Sources of Support for Gun Control.

    ERIC Educational Resources Information Center

    Kleck, Gary

    1996-01-01

    Questions whether attitudes towards gun control are influenced primarily by exposure to high crime rates, prior victimization, and fear of crime, or result from membership in social groups hostile to gun ownership. Maintains that support for gun control is more a product of culture conflict than a response to crime. (MJP)

  8. Managing residential sources of indoor air pollution

    SciTech Connect

    Tichenor, B.A.; Sparks, L.E.

    1994-12-31

    Sources of indoor air pollutants in residential environments can be managed to reduce occupant exposures. Techniques for managing indoor air pollution sources include: source elimination, substitution, modification, and pretreatment, and altering the amount, location, or time of use. Intelligent source management requires knowledge of the source`s emission characteristics, including chemical composition, emission rates, and decay rates. In addition, knowledge of outdoor air exchange rates, heating/air-conditioning duct flow rates, and kitchen/batch exhaust fan flow rates is needed to determine pollutant concentrations. Indoor air quality (IAQ) models use this information and occupant activity patterns to determine instantaneous and/or cumulative individual exposure. This paper describes a number of residential scenarios for various indoor air pollution VOC sources, several air flow conditions, and typical occupant activity patterns. IAQ model predictions of occupant exposures for these scenarios are given for selected source management options.

  9. The inner ears of Northern Canadian freshwater fishes following exposure to seismic air gun sounds.

    PubMed

    Song, Jiakun; Mann, David A; Cott, Peter A; Hanna, Bruce W; Popper, Arthur N

    2008-08-01

    An earlier study examined the effects of exposure to seismic air guns on the hearing of three species of fish from the Mackenzie River Delta in Northern Canada [Popper et al. (2005). "Effects of exposure to seismic airgun use on hearing of three fish species," J. Acoust. Soc. Am. 117, 3958-3971]. The sound pressure levels to which the fishes were exposed were a mean received level of 205-209 dB re 1 microPa (peak) per shot and an approximate received mean SEL of 176-180 dB re 1 microPa(2) s per shot. In this report, the same animals were examined to determine whether there were effects on the sensory cells of the inner ear as a result of the seismic exposure. No damage was found to the ears of the fishes exposed to seismic sounds despite the fact that two of the species, adult northern pike and lake chub, had shown a temporary threshold shift in hearing studies.

  10. Effects of multiple impulses from a seismic air gun on bottlenose dolphin hearing and behavior.

    PubMed

    Finneran, James J; Schlundt, Carolyn E; Branstetter, Brian K; Trickey, Jennifer S; Bowman, Victoria; Jenkins, Keith

    2015-04-01

    To investigate the auditory effects of multiple underwater impulses, hearing thresholds were measured in three bottlenose dolphins before and after exposure to 10 impulses produced by a seismic air gun. Thresholds were measured at multiple frequencies using both psychophysical and electrophysiological (auditory evoked potential) methods. Exposures began at relatively low levels and gradually increased over a period of several months. The highest exposures featured peak sound pressure levels from 196 to 210 dB re 1 μPa, peak-peak sound pressure levels of 200-212 dB re 1 μPa, and cumulative (unweighted) sound exposure levels from 193 to 195 dB re 1 μPa(2)s. At the cessation of the study, no significant increases were observed in psychophysical thresholds; however, a small (9 dB) shift in mean auditory evoked potential thresholds, accompanied by a suppression of the evoked potential amplitude function, was seen in one subject at 8 kHz. At the highest exposure condition, two of the dolphins also exhibited behavioral reactions indicating that they were capable of anticipating and potentially mitigating the effects of impulsive sounds presented at fixed time intervals.

  11. Carbon Nanotube Electron Gun

    NASA Technical Reports Server (NTRS)

    Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)

    2013-01-01

    An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.

  12. Carbon nanotube electron gun

    NASA Technical Reports Server (NTRS)

    Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)

    2010-01-01

    An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.

  13. Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source.

    PubMed

    Wells, R P; Ghiorso, W; Staples, J; Huang, T M; Sannibale, F; Kramasz, T D

    2016-02-01

    A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

  14. Mechanical design and fabrication of the VHF-gun, the Berkeley normal-conducting continuous-wave high-brightness electron source

    NASA Astrophysics Data System (ADS)

    Wells, R. P.; Ghiorso, W.; Staples, J.; Huang, T. M.; Sannibale, F.; Kramasz, T. D.

    2016-02-01

    A high repetition rate, MHz-class, high-brightness electron source is a key element in future high-repetition-rate x-ray free electron laser-based light sources. The VHF-gun, a novel low frequency radio-frequency gun, is the Lawrence Berkeley National Laboratory (LBNL) response to that need. The gun design is based on a normal conducting, single cell cavity resonating at 186 MHz in the VHF band and capable of continuous wave operation while still delivering the high accelerating fields at the cathode required for the high brightness performance. The VHF-gun was fabricated and successfully commissioned in the framework of the Advanced Photo-injector EXperiment, an injector built at LBNL to demonstrate the capability of the gun to deliver the required beam quality. The basis for the selection of the VHF-gun technology, novel design features, and fabrication techniques are described.

  15. Homemade Firearm Suicide With Dumbbell Pipe Triggering by an Air-Compressed Gun: Case Report and Review of Literature.

    PubMed

    Le Garff, Erwan; Delannoy, Yann; Mesli, Vadim; Berthezene, Jean Marie; Morbidelli, Philippe; Hédouin, Valéry

    2015-12-01

    Firearm suicides are frequent and well described in the forensic literature, particularly in Europe and the United States. However, the use of homemade and improvised firearms is less well described. The present case reports a suicide with an original improvised gun created using an air-compressed pellet gun and a dumbbell pipe. The aims of this study were to describe the scene, the external examination of the corpse, the body scan, and the autopsy; to understand the mechanism of death; and to compare the results with a review of the forensic literature to highlight the epidemiology of homemade firearm use, the tools used for homemade and improvised firearms in suicides versus homicides, and the manners in which homemade firearms are used (homicide or suicide, particularly in complex suicide cases).

  16. Evaluating sources of indoor air pollution

    SciTech Connect

    Tichenor, B.A.; Sparks, L.E.; White, J.B.; Jackson, M.D. )

    1988-01-01

    Scientists and engineers in the Indoor Air Brand of EPS'a Air and Energy Engineering Research Laboratory are conducting research to increase the state of knowledge concerning indoor air pollution factors. A three phase program is being implemented. The purpose of this paper is to show how their approach can be used to evaluate specific sources of indoor air pollution. Pollutants from two sources are examined: para-dichlorobenzene emissions from moth crystal cakes; and particulate emissions from unvented kerosene heaters.

  17. Rotating-bed reactor as a power source for EM gun applications

    SciTech Connect

    Powell, J.; Botts, T.; Stickley, C.M.; Meth, S.

    1980-01-01

    Electromagnetic gun applications of the Rotating Bed Reactor (RBR) are examined. The RBR is a compact (approx. 1 m/sup 3/), (up to several thousand MW(th)), high-power reactor concept, capable of producing a high-temperature (up to approx. 300/sup 0/K) gas stream with a MHD generator coupled to it, the RBR can generate electric power (up to approx. 1000 MW(e)) in the pulsed or cw modes. Three EM gun applications are investigated: a rail gun thruster for orbit transfer, a rapid-fire EM gun for point defense, and a direct ground-to-space launch. The RBR appears suitable for all applications.

  18. Evaluating sources of indoor air pollution

    SciTech Connect

    Tichenor, B.A.; Sparks, L.A.; White, J.B.; Jackson, M.D. )

    1990-04-01

    Evaluation of indoor air pollution problems requires an understanding of the relationship between sources, air movement, and outdoor air exchange. Research is underway to investigate these relationships. A three-phase program is being implemented: (1) Environmental chambers are used to provide source emission factors for specific indoor pollutants; (2) An IAQ (Indoor Air Quality) model has been developed to calculate indoor pollutant concentrations based on chamber emissions data and the air exchange and air movement within the indoor environment; and (3) An IAQ test house is used to conduct experiments to evaluate the model results. Examples are provided to show how this coordinated approach can be used to evaluate specific sources of indoor air pollution. Two sources are examined: (1) para-dichlorobenzene emissions from solid moth repellant; and (2) emissions from unvented kerosene heaters. The evaluation process for both sources followed the three-phase approach discussed above. Para-dichlorobenzene emission factors were determined by small chamber testing at EPA's Air and Energy Engineering Research Laboratory. Particle emission factors for the kerosene heaters were developed in large chambers at the J.B. Pierce Foundation Laboratory. Both sources were subsequently evaluated in EPA's IAQ test house. The IAQ model predictions showed good agreement with the test house measurements when appropriate values were provided for source emissions, outside air exchange, in-house air movement, and deposition on sink surfaces.

  19. High Power Experiment of X-Band Thermionic Cathode RF Gun for Compton Scattering X-ray Source

    SciTech Connect

    Sakamoto, Fumito; Uesaka, Mitsuru; Dobashi, Katsuhiro; Yamamoto, Tomohiko; Meng, De; Urakawa, Junji; Higo, Toshiyasu; Akemoto, Mitsuo; Matsuo, Kenichi; Sakae, Hisaharu; Yamamoto, Masashi

    2006-11-27

    We are currently developing a compact monochromatic X-ray source based on laser-electron collision. To realize remarkably compact-, high-intensity- and highly-stable-system, we adopt an X-band multi-bunch liner accelerator (linac) and reliable Q-switch laser. The X-ray yields by the multi-bunch electron beam and Q-switch Nd: YAG laser of 1.4 J/10 ns (FWHM) (532 nm, second harmonic) is 107 photons/RF-pulse (108 photons/sec for 10 Hz operation). The injector of the system consists of a 3.5-cell X-band thermionic cathode RF gun and an alpha magnet. So far we have achieved beam generation from the X-band thermionic cathode RF gun. The peak beam energy is 2 MeV. This experimental high energy ({approx}2 MeV) beam generation from the X-band thermionic cathode RF gun is the first in the world. In this paper, we describe the system of the Compton scattering X-ray source based on the X-band linac, experimental results of X-band thermionic cathode RF gun and the details of the experimental setup for Compton scattering X-ray generation that are under construction.

  20. A mulitple cathode gun design for the eRHIC polarized electron source

    SciTech Connect

    Chang, X.; Ben-Zvi, I.; Kewisch, J.; Litvinenko, V.; Pikin, A.; Ptitsyn, V.; Rao, T.; Sheehy, B.; Skaritka, J.; Wang, E.; Wu, Q.; Xin, T.

    2011-03-28

    The future electron-ion collider eRHIC requires a high average current ({approx}50 mA), short bunch ({approx}3 mm), low emittance ({approx}20 {micro}m) polarized electron source. The maximum average current of a polarized electron source so far is more than 1 mA, but much less than 50 mA, from a GaAs:Cs cathode. One possible approach to overcome the average current limit and to achieve the required 50 mA beam for eRHIC, is to combine beamlets from multiple cathodes to one beam. In this paper, we present the feasibility studies of this technique. The future eRHIC project, next upgrade of RHIC, will be the first electron-heavy ion collider in the world. It requires polarized electron source with a high average current ({approx}50 mA), short bunch ({approx}3 mm), emittance of about 20 {micro}m and energy spread of {approx}1% at 10 MeV. The state-of-art polarized electron cathode can generate average current of about more than 1 mA, but much less than 50 mA. The current is limited by the low quantum efficiency, space charge and ultra-high vacuum requirement of the polarized cathode. A possible approach to achieve the 50 mA beam is to employ multiple cathodes, such as 20 cathodes, and funnel the multiple bunched beams from cathodes to the same axis. Fig.1 illustrates schematically the concept of combining the multiple beams. We name it as 'Gatling gun' because it bears functional similarity to a Gatling gun. Laser beams strike the cathodes sequentially with revolution frequency of 700 kHz. Each beam bunch is focused by a solenoid and is bent toward the combiner. The combiner with rotating bending field bends all bunches arriving the combiner with a rotational pattern to the same axis. The energy of each bunch is modified by a bunching cavity (112MHz) and a 3rd harmonic cavity (336MHz). The bunch length is compressed ballistically in the drift space and is frozen after energy has been boosted to 10 MeV by the Booster linac. Each beam bunch contains 3.5 nC charge. The

  1. Shipboard assessment of hearing sensitivity of tropical fishes immediately after exposure to seismic air gun emissions at Scott Reef.

    PubMed

    Hastings, Mardi C; Miksis-Olds, Jennifer

    2012-01-01

    This is the first study to examine the potential effects of emissions from an air gun array on hearing of tropical reef fish using AEP thresholds measured in the field. Over 7 days, 51 Chromis viridis,47 Lutjanus kasmira, 20 Myripristis murdjan, and 10 Sargocentron spiniferum were tested. AEP thresholds were determined before and after exposure to emissions from one or two passes of an airgun array. Temporary threshold shift resulting from sound exposure was not found in any species,even when cumulative sound exposure levels reached 190 dB re 1 μPa2-s.

  2. 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…

  3. Rotating ned reactor as a power source for em gun applications

    SciTech Connect

    Powell, J.; Botts, T.; Stickley, C.M.; Meth, S.

    1982-01-01

    Electromagnetic gun applications of the Rotating Bed Reactor (RBR) are examined. The RBR is a compact (approximately 1 m/sup 3/), (up to several thousand MW(th), high-power reactor concept, capable of producing a high-temperature (up to approximately 3000/degree/K) gas stream with a MHD generator coupled to it. The RBR can generate electric power (up to approximately 1000 MW(e)) in the pulsed or cw modes. Three EM gun applications are investigated: a rail gun thruster for orbit transfer, a rapid-fire EM gun for point defense, and a direct ground-to-space launch. The RBR appears suitable for all applications. 4 refs.

  4. Improved DC Gun Insulator

    SciTech Connect

    M.L. Neubauer, K.B. Beard, R. Sah, C. Hernandez-Garcia, G. Neil

    2009-05-01

    Many user facilities such as synchrotron light sources and free electron lasers require accelerating structures that support electric fields of 10-100 MV/m, especially at the start of the accelerator chain where ceramic insulators are used for very high gradient DC guns. These insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic, creating a buildup of charge and causing eventual puncture. A novel ceramic manufacturing process is proposed. It will incorporate bulk resistivity in the region where it is needed to bleed off accumulated charge caused by highly energetic electrons. This process will be optimized to provide an appropriate gradient in bulk resistivity from the vacuum side to the air side of the HV standoff ceramic cylinder. A computer model will be used to determine the optimum cylinder dimensions and required resistivity gradient for an example RF gun application. A ceramic material example with resistivity gradient appropriate for use as a DC gun insulator will be fabricated by glazing using doping compounds and tested.

  5. SOURCE CHARACTERIZATION OF AIR FRESHENERS

    EPA Science Inventory

    The paper discusses research in which five air fresheners of two styles were analyzed for their constituent volatile organic compounds. Both styles were refills to be inserted into heated electric plug-in units; one refill released the fragrance from a gel pack insert and the oth...

  6. Source Emissions in Multipollutant Air Quality Management

    EPA Science Inventory

    Human activities and natural processes that emit pollutants into the ambient atmosphere are the underlying cause of all air quality problems. In a technical sense, we refer to these activities and processes as pollutant sources. Although air quality management is usually concerne...

  7. Seismic air gun exposure during early-stage embryonic development does not negatively affect spiny lobster Jasus edwardsii larvae (Decapoda:Palinuridae)

    PubMed Central

    Day, Ryan D.; McCauley, Robert D.; Fitzgibbon, Quinn P.; Semmens, Jayson M.

    2016-01-01

    Marine seismic surveys are used to explore for sub-seafloor oil and gas deposits. These surveys are conducted using air guns, which release compressed air to create intense sound impulses, which are repeated around every 8–12 seconds and can travel large distances in the water column. Considering the ubiquitous worldwide distribution of seismic surveys, the potential impact of exposure on marine invertebrates is poorly understood. In this study, egg-bearing female spiny lobsters (Jasus edwardsii) were exposed to signals from three air gun configurations, all of which exceeded sound exposure levels (SEL) of 185 dB re 1 μPa2·s. Lobsters were maintained until their eggs hatched and the larvae were then counted for fecundity, assessed for abnormal morphology using measurements of larval length and width, tested for larval competency using an established activity test and measured for energy content. Overall there were no differences in the quantity or quality of hatched larvae, indicating that the condition and development of spiny lobster embryos were not adversely affected by air gun exposure. These results suggest that embryonic spiny lobster are resilient to air gun signals and highlight the caution necessary in extrapolating results from the laboratory to real world scenarios or across life history stages. PMID:26947006

  8. Seismic air gun exposure during early-stage embryonic development does not negatively affect spiny lobster Jasus edwardsii larvae (Decapoda: Palinuridae).

    PubMed

    Day, Ryan D; McCauley, Robert D; Fitzgibbon, Quinn P; Semmens, Jayson M

    2016-03-07

    Marine seismic surveys are used to explore for sub-seafloor oil and gas deposits. These surveys are conducted using air guns, which release compressed air to create intense sound impulses, which are repeated around every 8-12 seconds and can travel large distances in the water column. Considering the ubiquitous worldwide distribution of seismic surveys, the potential impact of exposure on marine invertebrates is poorly understood. In this study, egg-bearing female spiny lobsters (Jasus edwardsii) were exposed to signals from three air gun configurations, all of which exceeded sound exposure levels (SEL) of 185 dB re 1 μPa(2) · s. Lobsters were maintained until their eggs hatched and the larvae were then counted for fecundity, assessed for abnormal morphology using measurements of larval length and width, tested for larval competency using an established activity test and measured for energy content. Overall there were no differences in the quantity or quality of hatched larvae, indicating that the condition and development of spiny lobster embryos were not adversely affected by air gun exposure. These results suggest that embryonic spiny lobster are resilient to air gun signals and highlight the caution necessary in extrapolating results from the laboratory to real world scenarios or across life history stages.

  9. Seismic air gun exposure during early-stage embryonic development does not negatively affect spiny lobster Jasus edwardsii larvae (Decapoda: Palinuridae).

    PubMed

    Day, Ryan D; McCauley, Robert D; Fitzgibbon, Quinn P; Semmens, Jayson M

    2016-01-01

    Marine seismic surveys are used to explore for sub-seafloor oil and gas deposits. These surveys are conducted using air guns, which release compressed air to create intense sound impulses, which are repeated around every 8-12 seconds and can travel large distances in the water column. Considering the ubiquitous worldwide distribution of seismic surveys, the potential impact of exposure on marine invertebrates is poorly understood. In this study, egg-bearing female spiny lobsters (Jasus edwardsii) were exposed to signals from three air gun configurations, all of which exceeded sound exposure levels (SEL) of 185 dB re 1 μPa(2) · s. Lobsters were maintained until their eggs hatched and the larvae were then counted for fecundity, assessed for abnormal morphology using measurements of larval length and width, tested for larval competency using an established activity test and measured for energy content. Overall there were no differences in the quantity or quality of hatched larvae, indicating that the condition and development of spiny lobster embryos were not adversely affected by air gun exposure. These results suggest that embryonic spiny lobster are resilient to air gun signals and highlight the caution necessary in extrapolating results from the laboratory to real world scenarios or across life history stages. PMID:26947006

  10. X-band RF gun and linac for medical Compton scattering X-ray source

    NASA Astrophysics Data System (ADS)

    Dobashi, Katsuhito; Uesaka, Mitsuru; Fukasawa, Atsushi; Sakamoto, Fumito; Ebina, Futaro; Ogino, Haruyuki; Urakawa, Junji; Higo, Toshiyasu; Akemoto, Mitsuo; Hayano, Hitoshi; Nakagawa, Keiichi

    2004-12-01

    Compton scattering hard X-ray source for 10-80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U.Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard (10-80 keV) X-rays with the intensities of 108-1010 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at a beam dump by adopting the deceleration of electrons after the Compton scattering. This realizes one beamline of a 3rd generation SR source at small facilities without heavy shielding. The final goal is that the linac and laser are installed on the moving gantry. We have designed the X-band (11.424 GHz) traveling-wave-type linac for the purpose. Numerical consideration by CAIN code and luminosity calculation are performed to estimate the X-ray yield. X-band thermionic-cathode RF-gun and RDS(Round Detuned Structure)-type X-band accelerating structure are applied to generate 50 MeV electron beam with 20 pC microbunches (104) for 1 microsecond RF macro-pulse. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2 J/10 ns is 107 photons/RF-pulse (108 photons/sec at 10 pps). We design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). 50 MW X-band klystron and compact modulator have been constructed and now under tuning. The construction of the whole system has started. X-ray generation and medical application will be performed in the early next year.

  11. ''Smart Gun'' Technology Update

    SciTech Connect

    WIRSBINSKI, JOHN W.

    2001-11-01

    This report is an update to previous ''smart gun'' work and the corresponding report that were completed in 1996. It incorporates some new terminology and expanded definitions. This effort is the product of an open source look at what has happened to the ''smart gun'' technology landscape since the 1996 report was published.

  12. Environment and air pollution like gun and bullet for low-income countries: war for better health and wealth.

    PubMed

    Zou, Xiang; Azam, Muhammad; Islam, Talat; Zaman, Khalid

    2016-02-01

    The objective of the study is to examine the impact of environmental indicators and air pollution on "health" and "wealth" for the low-income countries. The study used a number of promising variables including arable land, fossil fuel energy consumption, population density, and carbon dioxide emissions that simultaneously affect the health (i.e., health expenditures per capita) and wealth (i.e., GDP per capita) of the low-income countries. The general representation for low-income countries has shown by aggregate data that consist of 39 observations from the period of 1975-2013. The study decomposes the data set from different econometric tests for managing robust inferences. The study uses temporal forecasting for the health and wealth model by a vector error correction model (VECM) and an innovation accounting technique. The results show that environment and air pollution is the menace for low-income countries' health and wealth. Among environmental indicators, arable land has the largest variance to affect health and wealth for the next 10-year period, while air pollution exerts the least contribution to change health and wealth of low-income countries. These results indicate the prevalence of war situation, where environment and air pollution become visible like "gun" and "bullet" for low-income countries. There are required sound and effective macroeconomic policies to combat with the environmental evils that affect the health and wealth of the low-income countries.

  13. Environment and air pollution like gun and bullet for low-income countries: war for better health and wealth.

    PubMed

    Zou, Xiang; Azam, Muhammad; Islam, Talat; Zaman, Khalid

    2016-02-01

    The objective of the study is to examine the impact of environmental indicators and air pollution on "health" and "wealth" for the low-income countries. The study used a number of promising variables including arable land, fossil fuel energy consumption, population density, and carbon dioxide emissions that simultaneously affect the health (i.e., health expenditures per capita) and wealth (i.e., GDP per capita) of the low-income countries. The general representation for low-income countries has shown by aggregate data that consist of 39 observations from the period of 1975-2013. The study decomposes the data set from different econometric tests for managing robust inferences. The study uses temporal forecasting for the health and wealth model by a vector error correction model (VECM) and an innovation accounting technique. The results show that environment and air pollution is the menace for low-income countries' health and wealth. Among environmental indicators, arable land has the largest variance to affect health and wealth for the next 10-year period, while air pollution exerts the least contribution to change health and wealth of low-income countries. These results indicate the prevalence of war situation, where environment and air pollution become visible like "gun" and "bullet" for low-income countries. There are required sound and effective macroeconomic policies to combat with the environmental evils that affect the health and wealth of the low-income countries. PMID:26493298

  14. Magnetic Ignition of Pulsed Gas Discharges in Air of Low Pressure in a Coaxial Plasma Gun

    NASA Technical Reports Server (NTRS)

    Thom, Karlheinz; Norwood, Joseph, Jr.

    1961-01-01

    The effect of an axial magnetic field on the breakdown voltage of a coaxial system of electrodes has been investigated by earlier workers. For low values of gas pressure times electrode spacing, the breakdown voltage is decreased by the application of the magnetic field. The electron cyclotron radius now assumes the role held by the mean free path in nonmagnetic discharges and the breakdown voltage becomes a function of the magnetic flux density. In this paper the dependence of the formative time lag as a function of the magnetic flux density is established and the feasibility of using a magnetic field for igniting high-voltage, high-current discharges is shown through theory and experiment. With a 36 microfarad capacitor bank charged to 48,000 volts, a peak current of 1.3 x 10( exp 6) amperes in a coaxial type of plasma gun was achieved with a current rise time of only 2 microseconds.

  15. EVALUATING SOURCES OF INDOOR AIR POLLUTION

    EPA Science Inventory

    The article discusses a three-phase approach, employing environmental chambers, indoor air quality (IAQ) models, and test house experiments, that is effective in linking sources of indoor pollutants to measured concentrations. mission factors developed in test chambers can be use...

  16. Source apportionment of indoor air pollution

    NASA Astrophysics Data System (ADS)

    Sexton, Ken; Hayward, Steven B.

    An understanding of the relative contributions from important pollutant sources to human exposures is necessary for the design and implementation of effective control strategies. In the past, societal efforts to control air pollution have focused almost exclusively on the outdoor (ambient) environment. As a result, substantial amounts of time and money have been spent to limit airborne discharges from mobile and stationary sources. Yet it is now recognized that exposures to elevated pollutant concentrations often occur as a result of indoor, rather than outdoor, emissions. While the major indoor sources have been identified, their relative impacts on indoor air quality have not been well defined. Application of existing source apportionment models to nonindustrial indoor environments is only just beginning. It is possible that these models might be used to distinguish between indoor and outdoor emissions, as well as to distinguish among indoor sources themselves. However, before the feasibility and suitability of source-apportionment methods for indoor applications can be assessed adequately, it is necessary to take account of model assumptions and associated data requirements. This paper examines the issue of indoor source apportionment and reviews the need for emission characterization studies to support such source-apportionment efforts.

  17. ELECTRON GUN

    DOEpatents

    Christofilos, N.C.; Ehlers, K.W.

    1960-04-01

    A pulsed electron gun capable of delivering pulses at voltages of the order of 1 mv and currents of the order of 100 amperes is described. The principal novelty resides in a transformer construction which is disposed in the same vacuum housing as the electron source and accelerating electrode structure of the gun to supply the accelerating potential thereto. The transformer is provided by a plurality of magnetic cores disposed in circumferentially spaced relation and having a plurality of primary windings each inductively coupled to a different one of the cores, and a helical secondary winding which is disposed coaxially of the cores and passes therethrough in circumferential succession. Additional novelty resides in the disposition of the electron source cathode filament input leads interiorly of the transformer secondary winding which is hollow, as well as in the employment of a half-wave filament supply which is synchronously operated with the transformer supply such that the transformer is pulsed during the zero current portions of the half-wave cycle.

  18. Gun Safety

    MedlinePlus

    Many U.S. households have guns, but they can cause harm if not handled properly. Here are some things you can do to keep yourself and ... safe: Teach children that they shouldn't touch guns and that if they see a gun, to ...

  19. Laser-Free RF-Gun as a Combined Source of Thz and Ps-Sub-Ps X-Rays

    NASA Astrophysics Data System (ADS)

    Agustsson, R.; Boucher, S.; Finn, O.; Hartzell, J.; Ruelas, M.; Smirnov, A. V.; Storms, S.; Ning, Z.; Murokh, A.; Campese, T.; Faillace, L.; Verma, A.; Kim, Y.; Buaphad, P.; Andrews, A.; Berls, B.; Eckman, C.; Folkman, K.; Knowles-Swingle, A.; O'Neill, C.; Smith, M.; Grandsaert, T.; van der Geer, B.; de Loos, M.; Berg, W. J.; Sereno, N. S.; Sun, Y.; Zholents, A. A.

    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. The 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.

  20. Laser-free RF-gun as a combined source of THz and ps-sub-ps X-rays

    SciTech Connect

    Agustsson, R.; Boucher, S.; Finn, O.; Hartzell, J.; Ruelas, M.; Smirnov, A. V.; Storms, S.; Ning, Z.; Murokh, A.; Campese, T.; Faillace, L.; Verma, A.; Kim, Y.; Buaphad, P.; Andrews, A.; Berls, B.; Eckman, C.; Folkman, K.; Knowles-Swingle, A.; O’Neill, C.; Smith, M.; Grandsaert, T.; van der Geer, B.; de Loos, M.; Berg, W. J.; Sereno, N. S.; Sun, Y.; Zholents, A. A.

    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. The 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.

  1. Laser-free RF-gun as a combined source of THz and ps-sub-ps X-rays

    DOE PAGES

    Agustsson, R.; Boucher, S.; Finn, O.; Hartzell, J.; Ruelas, M.; Smirnov, A. V.; Storms, S.; Ning, Z.; Murokh, A.; Campese, T.; et al

    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

  2. Evaluating sources of indoor air pollution

    SciTech Connect

    Tichenor, B.A.; Sparks, L.E.; White, J.B.; Jackson, M.D.

    1988-05-01

    This paper discusses a three-phase approach, employing environmental chambers, indoor air quality (IAQ) models, and test-house experiments, that is effective in linking sources of indoor pollutants to measured concentrations. Emission factors developed in test chambers can be used to evaluate full-scale indoor environments. A PC-based IAQ model has been developed that can accurately predict indoor concentrations of specific pollutants under controlled conditions in a test house. The model is also useful in examining the effect of pollutant sinks and variations in ventilation parameters. Pollutants were examined from: (1) para-dichloro-benzene emissions from moth crystal cakes; and, (2) particulate emissions from unvented kerosene heaters. However, the approach has not been validated for other source types, including solvent based materials and aerosol products.

  3. Experimental evaluation of a mathematical model for predicting transfer efficiency of a high volume-low pressure air spray gun.

    PubMed

    Tan, Y M; Flynn, M R

    2000-10-01

    The transfer efficiency of a spray-painting gun is defined as the amount of coating applied to the workpiece divided by the amount sprayed. Characterizing this transfer process allows for accurate estimation of the overspray generation rate, which is important for determining a spray painter's exposure to airborne contaminants. This study presents an experimental evaluation of a mathematical model for predicting the transfer efficiency of a high volume-low pressure spray gun. The effects of gun-to-surface distance and nozzle pressure on the agreement between the transfer efficiency measurement and prediction were examined. Wind tunnel studies and non-volatile vacuum pump oil in place of commercial paint were used to determine transfer efficiency at nine gun-to-surface distances and four nozzle pressure levels. The mathematical model successfully predicts transfer efficiency within the uncertainty limits. The least squares regression between measured and predicted transfer efficiency has a slope of 0.83 and an intercept of 0.12 (R2 = 0.98). Two correction factors were determined to improve the mathematical model. At higher nozzle pressure settings, 6.5 psig and 5.5 psig, the correction factor is a function of both gun-to-surface distance and nozzle pressure level. At lower nozzle pressures, 4 psig and 2.75 psig, gun-to-surface distance slightly influences the correction factor, while nozzle pressure has no discernible effect. PMID:11036729

  4. RF Gun Optimization Study

    SciTech Connect

    A. S. Hofler; P. Evtushenko; M. Krasilnikov

    2007-08-01

    Injector gun design is an iterative process where the designer optimizes a few nonlinearly interdependent beam parameters to achieve the required beam quality for a particle accelerator. Few tools exist to automate the optimization process and thoroughly explore the parameter space. The challenging beam requirements of new accelerator applications such as light sources and electron cooling devices drive the development of RF and SRF photo injectors. RF and SRF gun design is further complicated because the bunches are space charge dominated and require additional emittance compensation. A genetic algorithm has been successfully used to optimize DC photo injector designs for Cornell* and Jefferson Lab**, and we propose studying how the genetic algorithm techniques can be applied to the design of RF and SRF gun injectors. In this paper, we report on the initial phase of the study where we model and optimize gun designs that have been benchmarked with beam measurements and simulation.

  5. Wisconsin SRF Electron Gun Commissioning

    SciTech Connect

    Bisognano, Joseph J.; Bissen, M.; Bosch, R.; Efremov, M.; Eisert, D.; Fisher, M.; Green, M.; Jacobs, K.; Keil, R.; Kleman, K.; Rogers, G.; Severson, M.; Yavuz, D. D.; Legg, Robert A.; Bachimanchi, Ramakrishna; Hovater, J. Curtis; Plawski, Tomasz; Powers, Thomas J.

    2013-12-01

    The University of Wisconsin has completed fabrication and commissioning of a low frequency (199.6 MHz) superconducting electron gun based on a quarter wave resonator (QWR) cavity. Its concept was optimized to be the source for a CW free electron laser facility. The gun design includes active tuning and a high temperature superconducting solenoid. We will report on the status of the Wisconsin SRF electron gun program, including commissioning experience and first beam measurements.

  6. Air Plasma Source for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Henriques, J.; Tatarova, E.; Dias, F. M.; Ferreira, C. M.; Gordiets, B.; IPFN-IST, 1049-001 LX, Portugal Team; Lebedev Physical Institute of the Russian Academy of Sciences Team

    2011-10-01

    Plasma interactions with living matter are presently at the frontiers of plasma research and development. Plasmas contain numerous agents that influence biological activity. They provide essentially two types of biocidal species: reactive species, such as oxygen atoms that lead to lethality of micro-organisms through erosion, and UV radiation that can damage the DNA strands. In this work we investigate a surface wave (2.45 GHz) driven discharge plasma in air, with a small admixture of water vapor, as a source of ground state O(3P) oxygen atoms, NO molecules and UV radiation. A theoretical model describing both the wave driven discharge zone and its flowing afterglow is used to analyze the performance of this plasma source. The predicted plasma-generated NO(X) and O(3P) concentrations and NO(γ) radiation intensity along the source are presented and discussed as a function of the microwave power and water vapor percentage in the gas mixture. To validate the theoretical predictions, the relative concentrations of species have been determined by Mass Spectrometry, Fourier Transform Infrared Spectroscopy and Optical Spectroscopy. Acknowledgment: This work was funded by the Portuguese Foundation for Science and Technology, under research contract PTDC/FIS/108411/2008.

  7. 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)

  8. Analysis of air quality management with emphasis on transportation sources

    NASA Technical Reports Server (NTRS)

    English, T. D.; Divita, E.; Lees, L.

    1980-01-01

    The current environment and practices of air quality management were examined for three regions: Denver, Phoenix, and the South Coast Air Basin of California. These regions were chosen because the majority of their air pollution emissions are related to mobile sources. The impact of auto exhaust on the air quality management process is characterized and assessed. An examination of the uncertainties in air pollutant measurements, emission inventories, meteorological parameters, atmospheric chemistry, and air quality simulation models is performed. The implications of these uncertainties to current air quality management practices is discussed. A set of corrective actions are recommended to reduce these uncertainties.

  9. Locating and estimating air emissions from sources of nickel

    SciTech Connect

    Not Available

    1984-03-01

    To assist groups interested in inventorying air emissions of various potentially toxic substances, EPA is preparing a series of documents such as this to compile available information on sources and emissions of these substances. This document deals specifically with nickel. Its intended audience includes Federal, State and local air pollution personnel and others interested in locating potential emitters of nickel and in making gross estimates of air emissions therefrom. This document presents information on (1) the types of sources that may emit nickel, (2) process variations and release points that may be expected within these sources, and (3) available emissions information indicating the potential for nickel release into the air from each operation.

  10. The National Near-Road Mobile Source Air Toxics Study

    EPA Science Inventory

    Recently, much attention has been directed at understanding the impact of mobile sources on near-road air quality, especially PM and its components, NOx and CO, but little information exists for mobile source air toxics (MSATs). MSATs of interest to this project are 1,3-butadiene...

  11. WORKSHOP ON SOURCE EMISSION AND AMBIENT AIR MONITORING OF MERCURY

    EPA Science Inventory

    AN EPA/ORD Workshop on Source Emission and Ambient Air Monitoring of Mercury was held on 9/13-14/99, Bloomington, Minnesota. The purpose of the workshop was to discuss the state-of-the-science in source and ambient air mercury monitoring as well as mercury monitoring research and...

  12. FEATURE A. CONCRETE ANTIAIRCRAFT GUN POSITION, VIEW FACING NORTHNORTHEAST. ...

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

    FEATURE A. CONCRETE ANTI-AIRCRAFT GUN POSITION, VIEW FACING NORTH-NORTHEAST. - Naval Air Station Barbers Point, Battery-Anti-Aircraft Gun Position, South of Point Cruz Road & west of Coral Sea Road, Ewa, Honolulu County, HI

  13. FEATURE 1, SMALL GUN POSITION, VIEW FACING NORTH, (with scale ...

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

    FEATURE 1, SMALL GUN POSITION, VIEW FACING NORTH, (with scale stick). - Naval Air Station Barbers Point, Anti-Aircraft Battery Complex-Small Gun Position, East of Coral Sea Road, northwest of Hamilton Road, Ewa, Honolulu County, HI

  14. FEATURE B. MACHINE GUN POSITION WITH LEWIS MOUNT, VIEW FACING ...

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

    FEATURE B. MACHINE GUN POSITION WITH LEWIS MOUNT, VIEW FACING NORTHWEST (with scale stick). - Naval Air Station Barbers Point, Battery-Machine Gun Positions, South of Point Cruz Road & west of Coral Sea Road, Ewa, Honolulu County, HI

  15. FEATURE B. MACHINE GUN POSITION WITH LEWIS MOUNT, VIEW FACING ...

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

    FEATURE B. MACHINE GUN POSITION WITH LEWIS MOUNT, VIEW FACING NORTHWEST. - Naval Air Station Barbers Point, Battery-Machine Gun Positions, South of Point Cruz Road & west of Coral Sea Road, Ewa, Honolulu County, HI

  16. FEATURE 1, SMALL GUN POSITION, VIEW FACING NORTH. Naval ...

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

    FEATURE 1, SMALL GUN POSITION, VIEW FACING NORTH. - Naval Air Station Barbers Point, Anti-Aircraft Battery Complex-Small Gun Position, East of Coral Sea Road, northwest of Hamilton Road, Ewa, Honolulu County, HI

  17. FEATURE C. MACHINE GUN POSITION WITH REMNANT OF MOUNT, VIEW ...

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

    FEATURE C. MACHINE GUN POSITION WITH REMNANT OF MOUNT, VIEW FACING SOUTH-SOUTHEAST. - Naval Air Station Barbers Point, Battery-Machine Gun Positions, South of Point Cruz Road & west of Coral Sea Road, Ewa, Honolulu County, HI

  18. FEATURE A. CONCRETE ANTIAIRCRAFT GUN POSITION, VIEW FACING NORTH ...

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

    FEATURE A. CONCRETE ANTI-AIRCRAFT GUN POSITION, VIEW FACING NORTH - NORTHEAST (with scale stick). - Naval Air Station Barbers Point, Battery-Anti-Aircraft Gun Position, South of Point Cruz Road & west of Coral Sea Road, Ewa, Honolulu County, HI

  19. 6. INTERIOR DETAIL OF GUN MOUNT ON TERRACE, LOOKING EAST ...

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

    6. INTERIOR DETAIL OF GUN MOUNT ON TERRACE, LOOKING EAST (1992). - Wright-Patterson Air Force Base, Area B, Building 22, Armament Laboratory & Gun Range, On flightline between Tenth & Eleventh Streets, Dayton, Montgomery County, OH

  20. FEATURE 3, LARGE GUN POSITION, SHOWING MULTIPLE COMPARTMENTS, VIEW FACING ...

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

    FEATURE 3, LARGE GUN POSITION, SHOWING MULTIPLE COMPARTMENTS, VIEW FACING SOUTH. - Naval Air Station Barbers Point, Anti-Aircraft Battery Complex-Large Gun Position, East of Coral Sea Road, northwest of Hamilton Road, Ewa, Honolulu County, HI

  1. FEATURE A. CONCRETE ANTIAIRCRAFT GUN POSITION, SHOWING CORAL RUBBLE BERM, ...

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

    FEATURE A. CONCRETE ANTI-AIRCRAFT GUN POSITION, SHOWING CORAL RUBBLE BERM, VIEW FACING SOUTHEAST. - Naval Air Station Barbers Point, Battery-Anti-Aircraft Gun Position, South of Point Cruz Road & west of Coral Sea Road, Ewa, Honolulu County, HI

  2. Spectrometer gun

    DOEpatents

    Waechter, D.A.; Wolf, M.A.; Umbarger, C.J.

    1981-11-03

    A hand-holdable, battery-operated, microprocessor-based spectrometer gun is described that includes a low-power matrix display and sufficient memory to permit both real-time observation and extended analysis of detected radiation pulses. Universality of the incorporated signal processing circuitry permits operation with various detectors having differing pulse detection and sensitivity parameters.

  3. Spectrometer gun

    DOEpatents

    Waechter, David A.; Wolf, Michael A.; Umbarger, C. John

    1985-01-01

    A hand-holdable, battery-operated, microprocessor-based spectrometer gun includes a low-power matrix display and sufficient memory to permit both real-time observation and extended analysis of detected radiation pulses. Universality of the incorporated signal processing circuitry permits operation with various detectors having differing pulse detection and sensitivity parameters.

  4. Borehole-explosion and air-gun data acquired in the 2011 Salton Seismic Imaging Project (SSIP), southern California: description of the survey

    USGS Publications Warehouse

    Rose, Elizabeth J.; Fuis, Gary S.; Stock, Joann M.; Hole, John A.; Kell, Annie M.; Kent, Graham; Driscoll, Neal W.; Goldman, Mark; Reusch, Angela M.; Han, Liang; Sickler, Robert R.; Catchings, Rufus D.; Rymer, Michael J.; Criley, Coyn J.; Scheirer, Daniel S.; Skinner, Steven M.; Slayday-Criley, Coye J.; Murphy, Janice M.; Jensen, Edward G.; McClearn, Robert; Ferguson, Alex J.; Butcher, Lesley A.; Gardner, Max A.; Emmons, Iain; Loughran, Caleb L.; Svitek, Joseph R.; Bastien, Patrick C.; Cotton, Joseph A.; Croker, David S.; Harding, Alistair J.; Babcock, Jeffrey M.; Harder, Steven H.; Rosa, Carla M.

    2013-01-01

    detailed images we need for earthquake hazard assessment. Air gun bursts, generated in the Salton Sea along extensions of our onshore seismic lines, also were utilized as sound-wave sources. Temporary deployments of portable land seismometers, as well as ocean-bottom seismometers (OBSs) on the floor of the Salton Sea, recorded the energy from the land shots and air gun bursts. SSIP is similar to the Los Angeles Regional Seismic Experiments of 1994 and 1999 (LARSE I and II, respectively; Murphy and others, 1996; Fuis and others, 2001). The LARSE surveys demonstrated that the USGS and collaborators can safely and effectively conduct seismic imaging surveys in urban and nonurban areas, on lands owned and/or managed by many different types of agencies and entities. Information was produced that could not have been obtained any other way, and this information was key to changing the leading ideas about earthquake hazards at that time in the Los Angeles region. These surveys produced no significant environmental impact or damage to structures, and they did not trigger earthquakes.

  5. 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.

  6. Air toxics: sources and monitoring in Texas.

    PubMed Central

    Pendleton, D R

    1995-01-01

    Since the late 1980s, federal legislation has required industries to publicly report their annual emissions of toxic compounds. Industry reports show the largest contributor to toxic emission levels in Texas is the massive concentration of petrochemical industries along the Gulf Coast. It is interesting to note that although Texas produces over 50% of the nation's synthetic chemicals, it discharges less than 8% of the nation's toxic emissions. However, in response to growing concerns about the effects of these toxic emissions, the Texas Natural Resource Conservation Commission (TNRCC) initiated a long-term program for monitoring toxic chemicals in the air. This article provides details of this monitoring program as well as industry-funded toxic monitoring networks in Texas. This includes information on the technology currently being used for sample collection and analysis as well as plans for implementing methods that are on the technological horizon. Finally, details of some key measurements from the state's air toxics monitoring network will be provided along with an explanation of how they impact current air quality trends in Texas. PMID:8549477

  7. Near-source air pollution and mitigation strategies

    EPA Science Inventory

    Abstract. Local-scale air pollution impact is of concern for populations located in close proximity to transit sources, including highway, port, rail, and other areas of concentrated diesel emissions. Previous near-road air monitoring research has prompted the U.S. EPA to implem...

  8. Short haul air passenger data sources in the United States

    NASA Technical Reports Server (NTRS)

    Al-Kazily, J.; Gosling, G.; Horonjeff, R.

    1977-01-01

    The sources and characteristics of existing data on short haul air passenger traffic in the United States domestic air market are described along with data availability, processing, and costs. Reference is made to data derived from aircraft operations since these data can be used to insure that no short haul operators are omitted during the process of assembling passenger data.

  9. Spot-Welding Gun Is Easy To Use

    NASA Technical Reports Server (NTRS)

    Morgan, Gene E.; Nguyen, Francis H.

    1991-01-01

    Electrical-resistance spot-welding gun designed to produce more welds per unit time by decreasing technician's effort and fatigue. Vacuum cups on frame secure welding gun to workpiece while compressed air drives welding tip against workpiece to make spot resistance weld. When weld completed, vacuum in frame cups released so frame and gun moved to position of next spot weld.

  10. 42 CFR 84.142 - Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators; minimum requirements. 84.142 Section 84.142 Public....142 Air supply source; hand-operated or motor driven air blowers; Type A supplied-air...

  11. 42 CFR 84.142 - Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators; minimum requirements. 84.142 Section 84.142 Public....142 Air supply source; hand-operated or motor driven air blowers; Type A supplied-air...

  12. 42 CFR 84.142 - Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators; minimum requirements. 84.142 Section 84.142 Public....142 Air supply source; hand-operated or motor driven air blowers; Type A supplied-air...

  13. 42 CFR 84.142 - Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators; minimum requirements. 84.142 Section 84.142 Public....142 Air supply source; hand-operated or motor driven air blowers; Type A supplied-air...

  14. 42 CFR 84.142 - Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators; minimum requirements. 84.142 Section 84.142 Public....142 Air supply source; hand-operated or motor driven air blowers; Type A supplied-air...

  15. X-Band RF Gun Development

    SciTech Connect

    Vlieks, Arnold; Dolgashev, Valery; Tantawi, Sami; Anderson, Scott; Hartemann, Fred; Marsh, Roark; /LLNL, Livermore

    2012-06-22

    In support of the MEGa-ray program at LLNL and the High Gradient research program at SLAC, a new X-band multi-cell RF gun is being developed. This gun, similar to earlier guns developed at SLAC for Compton X-ray source program, will be a standing wave structure made of 5.5 cells operating in the pi mode with copper cathode. This gun was designed following criteria used to build SLAC X-band high gradient accelerating structures. It is anticipated that this gun will operate with surface electric fields on the cathode of 200 MeV/m with low breakdown rate. RF will be coupled into the structure through a final cell with symmetric duel feeds and with a shape optimized to minimize quadrupole field components. In addition, geometry changes to the original gun, operated with Compton X-ray source, will include a wider RF mode separation, reduced surface electric and magnetic fields.

  16. Development of a low-energy and high-current pulsed neutral beam injector with a washer-gun plasma source for high-beta plasma experiments.

    PubMed

    Ii, Toru; Gi, Keii; Umezawa, Toshiyuki; Asai, Tomohiko; Inomoto, Michiaki; Ono, Yasushi

    2012-08-01

    We have developed a novel and economical neutral-beam injection system by employing a washer-gun plasma source. It provides a low-cost and maintenance-free ion beam, thus eliminating the need for the filaments and water-cooling systems employed conventionally. In our primary experiments, the washer gun produced a source plasma with an electron temperature of approximately 5 eV and an electron density of 5 × 10(17) m(-3), i.e., conditions suitable for ion-beam extraction. The dependence of the extracted beam current on the acceleration voltage is consistent with space-charge current limitation, because the observed current density is almost proportional to the 3/2 power of the acceleration voltage below approximately 8 kV. By optimizing plasma formation, we successfully achieved beam extraction of up to 40 A at 15 kV and a pulse length in excess of 0.25 ms. Its low-voltage and high-current pulsed-beam properties enable us to apply this high-power neutral beam injection into a high-beta compact torus plasma characterized by a low magnetic field.

  17. Development of a low-energy and high-current pulsed neutral beam injector with a washer-gun plasma source for high-beta plasma experiments

    NASA Astrophysics Data System (ADS)

    Ii, Toru; Gi, Keii; Umezawa, Toshiyuki; Asai, Tomohiko; Inomoto, Michiaki; Ono, Yasushi

    2012-08-01

    We have developed a novel and economical neutral-beam injection system by employing a washer-gun plasma source. It provides a low-cost and maintenance-free ion beam, thus eliminating the need for the filaments and water-cooling systems employed conventionally. In our primary experiments, the washer gun produced a source plasma with an electron temperature of approximately 5 eV and an electron density of 5 × 1017 m-3, i.e., conditions suitable for ion-beam extraction. The dependence of the extracted beam current on the acceleration voltage is consistent with space-charge current limitation, because the observed current density is almost proportional to the 3/2 power of the acceleration voltage below approximately 8 kV. By optimizing plasma formation, we successfully achieved beam extraction of up to 40 A at 15 kV and a pulse length in excess of 0.25 ms. Its low-voltage and high-current pulsed-beam properties enable us to apply this high-power neutral beam injection into a high-beta compact torus plasma characterized by a low magnetic field.

  18. Borehole-explosion and air-gun data acquired in the 2011 Salton Seismic Imaging Project (SSIP), southern California: description of the survey

    USGS Publications Warehouse

    Rose, Elizabeth J.; Fuis, Gary S.; Stock, Joann M.; Hole, John A.; Kell, Annie M.; Kent, Graham; Driscoll, Neal W.; Goldman, Mark; Reusch, Angela M.; Han, Liang; Sickler, Robert R.; Catchings, Rufus D.; Rymer, Michael J.; Criley, Coyn J.; Scheirer, Daniel S.; Skinner, Steven M.; Slayday-Criley, Coye J.; Murphy, Janice M.; Jensen, Edward G.; McClearn, Robert; Ferguson, Alex J.; Butcher, Lesley A.; Gardner, Max A.; Emmons, Iain; Loughran, Caleb L.; Svitek, Joseph R.; Bastien, Patrick C.; Cotton, Joseph A.; Croker, David S.; Harding, Alistair J.; Babcock, Jeffrey M.; Harder, Steven H.; Rosa, Carla M.

    2013-01-01

    detailed images we need for earthquake hazard assessment. Air gun bursts, generated in the Salton Sea

  19. The use of video for air pollution source monitoring

    SciTech Connect

    Ferreira, F.; Camara, A.

    1999-07-01

    The evaluation of air pollution impacts from single industrial emission sources is a complex environmental engineering problem. Recent developments in multimedia technologies used by personal computers improved the digitizing and processing of digital video sequences. This paper proposes a methodology where statistical analysis of both meteorological and air quality data combined with digital video images are used for monitoring air pollution sources. One of the objectives of this paper is to present the use of image processing algorithms in air pollution source monitoring. CCD amateur video cameras capture images that are further processed by computer. The use of video as a remote sensing system was implemented with the goal of determining some particular parameters, either meteorological or related with air quality monitoring and modeling of point sources. These parameters include the remote calculation of wind direction, wind speed, gases stack's outlet velocity, and stack's effective emission height. The characteristics and behavior of a visible pollutant's plume is also studied. Different sequences of relatively simple image processing operations are applied to the images gathered by the different cameras to segment the plume. The algorithms are selected depending on the atmospheric and lighting conditions. The developed system was applied to a 1,000 MW fuel power plant located at Setubal, Portugal. The methodology presented shows that digital video can be an inexpensive form to get useful air pollution related data for monitoring and modeling purposes.

  20. RF Gun Optimization Study

    SciTech Connect

    Alicia Hofler; Pavel Evtushenko

    2007-07-03

    Injector gun design is an iterative process where the designer optimizes a few nonlinearly interdependent beam parameters to achieve the required beam quality for a particle accelerator. Few tools exist to automate the optimization process and thoroughly explore the parameter space. The challenging beam requirements of new accelerator applications such as light sources and electron cooling devices drive the development of RF and SRF photo injectors. A genetic algorithm (GA) has been successfully used to optimize DC photo injector designs at Cornell University [1] and Jefferson Lab [2]. We propose to apply GA techniques to the design of RF and SRF gun injectors. In this paper, we report on the initial phase of the study where we model and optimize a system that has been benchmarked with beam measurements and simulation.

  1. 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…

  2. 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.

  3. ION GUN

    DOEpatents

    Dandl, R.A.

    1961-10-24

    An ion gun is described for the production of an electrically neutral ionized plasma. The ion gun comprises an anode and a cathode mounted in concentric relationship with a narrow annulus between. The facing surfaces of the rear portions of the anode and cathode are recessed to form an annular manifold. Positioned within this manifold is an annular intermediate electrode aligned with the an nulus between the anode and cathode. Gas is fed to the manifold and an arc discharge is established between the anode and cathode. The gas is then withdrawn from the manifold through the annulus between the anode and cathode by a pressure differential. The gas is then ionized by the arc discharge across the annulus. The ionized gas is withdrawn from the annulus by the combined effects of the pressure differential and a collimating magnetic field. In a 3000 gauss magnetic field, an arc voltage of 1800 volts, and an arc current of 0.2 amp, a plasma of about 3 x 10/sup 11/ particles/cc is obtained. (AEC)

  4. Piezoelectric-based event sensing and energy-harvesting power sources for thermal battery initiation in gun-fired munitions

    NASA Astrophysics Data System (ADS)

    Rastegar, J.; Feng, D.; Pereira, C.

    2014-06-01

    A novel class of piezoelectric-based energy harvesting devices with integrated safety and firing setback event detection electronics and logic circuitry that can be used in gun-fired munitions is presented. In this paper, the application of the device to the development of initiators for thermal reserve batteries in gun-fire munitions is presented. The novel and highly efficient electrical energy collection and storage and event detection and safety electronics used allows the use of a very small piezoelectric element. As a result, such devices can be highly miniaturized for used in small reserve batteries. For thermal battery initiation, when the prescribed firing setback acceleration profile, i.e., the prescribed all-fire condition is detected, a highly efficient charge collection electronic circuitry routes the charges generated by the piezoelectric element of the device to the initiator bridge element, thereby causing the thermal battery pyrotechnic material to be ignited. For munitions powered by thermal reserve batteries, the present initiation device provides a self-powered initiator with full no-fire safety circuitry for protection against accidental drops, transportation vibration, and other similar low amplitude accelerations and/or high amplitude but short duration acceleration events. The device is shown to be readily set to initiate thermal batteries under almost any all-fire conditions. The device can be readily hardened to withstand very high G firing setback accelerations in excess of 100,000 G and the harsh firing environment. The design of prototypes and testing under realistic conditions are presented.

  5. Identifying the contribution of different urban highway air pollution sources.

    PubMed

    Peace, H; Owen, B; Raper, D W

    2004-12-01

    This paper describes the methodology and results, and draws conclusions from a large-scale source apportionment study undertaken in a large urban conurbation in the northwest of England. Annual average oxides of nitrogen (NOx) emission and ambient air pollution contributions have been estimated for road traffic sources. Ground level air pollution concentrations were estimated over a 1552-km(2) area with a resolution of up to 20 m, using emissions estimates and the second generation ADMS-Urban Gaussian dispersion model. Road traffic emissions were split into car and motorcycles; heavy and light goods vehicles; and buses to represent domestic users; commercial users and bus companies. Car related emissions were split further in to journey lengths under 3 km; journeys between 3 and 8 km; and journeys over 8 km to represent journeys which could be either walked or cycled; journeys for which a bus can easily be used and other journeys. These source sections were chosen so that the relevant authorities could target key groups in terms of reducing air pollution. The results confirm that the areas most likely to exceed air quality objectives are typically close to main arterial routes and close to urban centres and that the major culprits of road traffic related air pollution are goods vehicles and car journeys over 8 km. The paper also discusses the implications of the results and suggests how these can be used in the assessment of actions to reduce air pollution concentrations. PMID:15504521

  6. Temperature distribution of air source heat pump barn with different air flow

    NASA Astrophysics Data System (ADS)

    He, X.; Li, J. C.; Zhao, G. Q.

    2016-08-01

    There are two type of airflow form in tobacco barn, one is air rising, the other is air falling. They are different in the structure layout and working principle, which affect the tobacco barn in the distribution of temperature field and velocity distribution. In order to compare the temperature and air distribution of the two, thereby obtain a tobacco barn whose temperature field and velocity distribution are more uniform. Taking the air source heat pump tobacco barn as the investigated subject and establishing relevant mathematical model, the thermodynamics of the two type of curing barn was analysed and compared based on Fluent. Provide a reasonable evidence for chamber arrangement and selection of outlet for air source heat pump tobacco barn.

  7. 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)

  8. 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…

  9. 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

  10. Heat management in aluminum/air batteries: Sources of heat

    NASA Astrophysics Data System (ADS)

    Patnaik, R. S. M.; Ganesh, S.; Ashok, G.; Ganesan, M.; Kapali, V.

    1994-07-01

    One of the problems with the aluminum/air battery is the generation of heat, during both idle and discharge periods. The main sources of heat are: (1) corrosion of the aluminum anode during the idle period; (2) inefficient, or less efficient, dissolution of anode during discharge; (3) Joule heat during discharge, and (4) non-uniform mass transfer during both discharge and idle periods. These components of heat act in a cumulative way because they are all interconnected. This paper addresses the basic reasons for the origin of these sources of heat. Suitable and practical remedial measures for the effective removal of such heat in the aluminum/air battery are suggested.

  11. Mobile Source Air Toxics Rule (released in AEO2008)

    EIA Publications

    2008-01-01

    On February 9, 2007, the Environmental Protection Agency (EPA) released its MSAT2 rule, which will establish controls on gasoline, passenger vehicles, and portable fuel containers. The controls are designed to reduce emissions of benzene and other hazardous air pollutants. Benzene is a known carcinogen, and the EPA estimates that mobile sources produced more than 70% of all benzene emissions in 1999. Other mobile source air toxics, including 1,3-butadiene, formaldehyde, acetaldehyde, acrolein, and naphthalene, also are thought to increase cancer rates or contribute to other serious health problems.

  12. Response of humpback whales (Megaptera novaeangliae) to ramp-up of a small experimental air gun array.

    PubMed

    Dunlop, Rebecca A; Noad, Michael J; McCauley, Robert D; Kniest, Eric; Slade, Robert; Paton, David; Cato, Douglas H

    2016-02-15

    'Ramp-up', or 'soft start', is a mitigation measure used in seismic surveys and involves increasing the radiated sound level over 20-40 min. This study compared the behavioural response in migrating humpback whales to the first stages of ramp-up with the response to a 'constant' source, 'controls' (in which the array was towed but not operated) with groups in the absence of the source vessel used as the 'baseline'. Although the behavioural response, in most groups, resulted in an increase in distance from the source (potential avoidance), there was no evidence that either 'ramp-up' or the constant source at a higher level was superior for triggering whales to move away from the source vessel. 'Control' groups also responded suggesting the presence of the source vessel had some effect. However, the majority of groups appeared to avoid the source vessel at distances greater than the radius of most mitigation zones.

  13. Response of humpback whales (Megaptera novaeangliae) to ramp-up of a small experimental air gun array.

    PubMed

    Dunlop, Rebecca A; Noad, Michael J; McCauley, Robert D; Kniest, Eric; Slade, Robert; Paton, David; Cato, Douglas H

    2016-02-15

    'Ramp-up', or 'soft start', is a mitigation measure used in seismic surveys and involves increasing the radiated sound level over 20-40 min. This study compared the behavioural response in migrating humpback whales to the first stages of ramp-up with the response to a 'constant' source, 'controls' (in which the array was towed but not operated) with groups in the absence of the source vessel used as the 'baseline'. Although the behavioural response, in most groups, resulted in an increase in distance from the source (potential avoidance), there was no evidence that either 'ramp-up' or the constant source at a higher level was superior for triggering whales to move away from the source vessel. 'Control' groups also responded suggesting the presence of the source vessel had some effect. However, the majority of groups appeared to avoid the source vessel at distances greater than the radius of most mitigation zones. PMID:26781958

  14. Standard operating procedure for air quality stationary source management at Air Force installations in the Air Force Materiel Command

    SciTech Connect

    Powell, C.M.; Ryckman, S.J.

    1997-12-31

    To sustain compliance and avoid future enforcement actions associated with air quality stationary sources and to provide installation commanders with a certification process for Title V permitting, and Air Force Materiel Command (AFMC) Standard Operating Procedure (SOP) for Stationary Source Management has been developed. The SOP consists of two major sections: Stationary Source Planning and Administration, and Stationary Source Operations These two main sections are further subdivided into twelve subsections which delineate requirements (e.g. maintaining inventories, applying for and maintaining permits, keeping records, reporting and certifying compliance) and assign ownership of processes and responsibilities (e.g. appointing a manager/alternate for each identified stationary air source). In addition, the SOP suggests training that should be provided from operator to commander levels to ensure that all personnel involved with a stationary air source are aware of their responsibilities. Implementation of the SOP should provide for the essential control necessary for installation commanders to eliminate stationary air source non-compliance and to certify compliance in accordance with the Title V Operating Permit requirements. This paper will discuss: the background and purpose for the SOPs content, the twelve subsections of the SOP, the success of implementation at various installations, the relevance or the recommended training, the success of negotiating with various labor unions for SOP implementation and the success of the SOP in reference to its intended purpose.

  15. Modification of anisotropic plasma diffusion via auxiliary electrons emitted by a carbon nanotubes-based electron gun in an electron cyclotron resonance ion source.

    PubMed

    Malferrari, L; Odorici, F; Veronese, G P; Rizzoli, R; Mascali, D; Celona, L; Gammino, S; Castro, G; Miracoli, R; Serafino, T

    2012-02-01

    The diffusion mechanism in magnetized plasmas is a largely debated issue. A short circuit model was proposed by Simon, assuming fluxes of lost particles along the axial (electrons) and radial (ions) directions which can be compensated, to preserve the quasi-neutrality, by currents flowing throughout the conducting plasma chamber walls. We hereby propose a new method to modify Simon's currents via electrons injected by a carbon nanotubes-based electron gun. We found this improves the source performances, increasing the output current for several charge states. The method is especially sensitive to the pumping frequency. Output currents for given charge states, at different auxiliary electron currents, will be reported in the paper and the influence of the frequency tuning on the compensation mechanism will be discussed.

  16. The Sources of Air Pollution and Their Control.

    ERIC Educational Resources Information Center

    National Air Pollution Control Administration (DHEW), Arlington, VA.

    The problems of air pollution and its control are discussed. Major consideration is given the sources of pollution - motor vehicles, industry, power plants, space heating, and refuse disposal. Annual emission levels of five principle pollutants - carbon monoxide, sulfur dioxide, nitrogen oxides, hydrocarbons, and particulate matter - are listed…

  17. AIRBORNE PARTICLE SIZES AND SOURCES FOUND IN INDOOR AIR

    EPA Science Inventory

    The paper summarizes results of a literature search into the sources, sizes, and concentrations of particles in indoor air, including the various types: plant, animal, mineral, combustion, home/personal care, and radioactive aerosols. This information, presented in a summary figu...

  18. An Air Quality Data Analysis System for Interrelating Effects, Standards and Needed Source Reductions

    ERIC Educational Resources Information Center

    Larsen, Ralph I.

    1973-01-01

    Makes recommendations for a single air quality data system (using average time) for interrelating air pollution effects, air quality standards, air quality monitoring, diffusion calculations, source-reduction calculations, and emission standards. (JR)

  19. Effect of low emission sources on air quality in Cracow

    SciTech Connect

    Nedoma, J.

    1995-12-31

    The paper presents calculation of power engineering low emission and results of stimulation of the effect of this emission on air quality in Cracow, Poland. It has been stated that the segment of low emission in central areas of the town makes up ca. 40% of the observed concentration of sulfur dioxide. Furthermore it has been stated that the capital investment must be concentrated in the central part of the town in order to reach noticeable improvement of air quality in Cracow. Neither the output of a separate power source nor the emission level and its individual harmful effect, but the location of the source and especially packing density of the sources must decide the priority of upgrading actions.

  20. Natural sources of atmospheric aerosols influencing air quality across Europe.

    PubMed

    Viana, M; Pey, J; Querol, X; Alastuey, A; de Leeuw, F; Lükewille, Anke

    2014-02-15

    Atmospheric aerosols are emitted by natural and anthropogenic sources. Contributions from natural sources to ambient aerosols vary widely with time (inter-annual and seasonal variability) and as a function of the distance to source regions. This work aims to identify the main natural sources of atmospheric aerosols affecting air quality across Europe. The origin, frequency, magnitude, and spatial and temporal variability of natural events were assessed for the years 2008 and 2009. The main natural sources of atmospheric aerosols identified were African dust, sea spray and wildfires. Primary biological particles were not included in the present work. Volcanic eruptions did not affect air quality significantly in Europe during the study period. The impact of natural episodes on air quality was significant in Southern and Western Europe (Cyprus, Spain, France, UK, Greece, Malta, Italy and Portugal), where they contributed to surpass the PM10 daily and annual limit values. In Central and Northern Europe (Germany, Austria and Latvia) the impact of these events was lower, as it resulted in the exceedance of PM daily but not annual limit values. Contributions from natural sources to mean annual PM10 levels in 2008 and 2009 ranged between 1 and 2 μg/m(3) in Italy, France and Portugal, between 1 and 4 μg/m(3) in Spain (10 μg/m(3) when including the Canary Islands), 5 μg/m(3) in UK, between 3 and 8 μg/m(3) in Greece, and reached up to 13 μg/m(3) in Cyprus. The evaluation of the number of monitoring stations per country reporting natural exceedances of the daily limit value (DLV) is suggested as a potential tool for air quality monitoring networks to detect outliers in the assessment of natural contributions. It is strongly suggested that a reference methodology for the identification and quantification of African dust contributions should be adopted across Europe. PMID:24342088

  1. Modeling population exposures to outdoor sources of hazardous air pollutants.

    PubMed

    Ozkaynak, Halûk; Palma, Ted; Touma, Jawad S; Thurman, James

    2008-01-01

    Accurate assessment of human exposures is an important part of environmental health effects research. However, most air pollution epidemiology studies rely upon imperfect surrogates of personal exposures, such as information based on available central-site outdoor concentration monitoring or modeling data. In this paper, we examine the limitations of using outdoor concentration predictions instead of modeled personal exposures for over 30 gaseous and particulate hazardous air pollutants (HAPs) in the US. The analysis uses the results from an air quality dispersion model (the ASPEN or Assessment System for Population Exposure Nationwide model) and an inhalation exposure model (the HAPEM or Hazardous Air Pollutant Exposure Model, Version 5), applied by the US. Environmental protection Agency during the 1999 National Air Toxic Assessment (NATA) in the US. Our results show that the total predicted chronic exposure concentrations of outdoor HAPs from all sources are lower than the modeled ambient concentrations by about 20% on average for most gaseous HAPs and by about 60% on average for most particulate HAPs (mainly, due to the exclusion of indoor sources from our modeling analysis and lower infiltration of particles indoors). On the other hand, the HAPEM/ASPEN concentration ratio averages for onroad mobile source exposures were found to be greater than 1 (around 1.20) for most mobile-source related HAPs (e.g. 1, 3-butadiene, acetaldehyde, benzene, formaldehyde) reflecting the importance of near-roadway and commuting environments on personal exposures to HAPs. The distribution of the ratios of personal to ambient concentrations was found to be skewed for a number of the VOCs and reactive HAPs associated with major source emissions, indicating the importance of personal mobility factors. We conclude that the increase in personal exposures from the corresponding predicted ambient levels tends to occur near locations where there are either major emission sources of HAPs

  2. Establishing reliable good initial quantum efficiency and in-situ laser cleaning for the copper cathodes in the RF gun

    NASA Astrophysics Data System (ADS)

    Zhou, F.; Sheppard, J. C.; Vecchione, T.; Jongewaard, E.; Brachmann, A.; Corbett, J.; Gilevich, S.; Weathersby, S.

    2015-05-01

    Establishing good initial quantum efficiency (QE) and reliable in-situ cleaning for copper cathode in the RF gun is of critical importance for the RF gun operations. Recent studies on the SLAC RF gun test bed indicated that the pre-cleaning (plasma cleaning) in the test chamber followed by copper cathode exposure to air for cathode change leads to a very low initial QE in the RF gun, and also demonstrated that without the pre-cleaning good initial QE >4×10-5 can be routinely achieved in the RF gun with the cathodes of QE <1×10-7 measured in the test chamber. QE can decay over the time in the RF gun. The in-situ laser cleaning technique for copper cathodes in the RF gun is established and refined in comparison to previous cleaning at the linac coherent light source, resulting in an improved QE and emittance evolutions. The physics of the laser cleaning process is discussed. It is believed that the reflectivity change is one of the major factors for the QE boost with the laser cleaning.

  3. HVAC SYSTEMS AS EMISSION SOURCES AFFECTING INDOOR AIR QUALITY: A CRITICAL REVIEW

    EPA Science Inventory

    The study evaluates heating, ventilating, and air-conditioning (HVAC) systems as contaminant emission sources that affect indoor air quality (IAQ). Various literature sources and methods for characterizing HVAC emission sources are reviewed. Available methods include in situ test...

  4. 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…

  5. Advances in DC photocathode electron guns

    SciTech Connect

    Bruce M. Dunham; P. Heartmann; Reza Kazimi; Hongxiu Liu; B. M. Poelker; J. S. Price; P. M. Rutt; W. J. Schneider; Charles K. Sinclair

    1998-07-01

    At Jefferson Lab, a DC photoemission gun using GaAs and GaAs-like cathodes provides a source of polarized electrons for the main accelerator. The gun is required to produce high average current with long operational lifetimes and high system throughout. Recent work has shown that careful control of the parameters affecting cathode lifetime lead to dramatic improvements in source operation. These conditions include vacuum and the related effect of ion backbombardment, and precise control of all of the electrons emitted from the cathode. In this paper, the authors will review recent results and discuss implications for future photocathode guns.

  6. Gun Safety (For Kids)

    MedlinePlus

    ... guns are featured in many television shows, video games, computer games, and movies, it's important to know that real ... only happen on TV, in movies, or video games. A real gun is never a toy, and ...

  7. Indoor air quality environmental information handbook: Combustion sources

    SciTech Connect

    Not Available

    1990-06-01

    This environmental information handbook was prepared to assist both the non-technical reader (i.e., homeowner) and technical persons (such as researchers, policy analysts, and builders/designers) in understanding the current state of knowledge regarding combustion sources of indoor air pollution. Quantitative and descriptive data addressing the emissions, indoor concentrations, factors influencing indoor concentrations, and health effects of combustion-generated pollutants are provided. In addition, a review of the models, controls, and standards applicable to indoor air pollution from combustion sources is presented. The emphasis is on the residential environment. The data presented here have been compiled from government and privately-funded research results, conference proceedings, technical journals, and recent publications. It is intended to provide the technical reader with a comprehensive overview and reference source on the major indoor air quality aspects relating to indoor combustion activities, including tobacco smoking. In addition, techniques for determining potential concentrations of pollutants in residential settings are presented. This is an update of a 1985 study documenting the state of knowledge of combustion-generated pollutants in the indoor environment. 191 refs., 51 figs., 71 tabs.

  8. Source apportionment of visibility impairment using a three-dimensional source-oriented air quality model.

    PubMed

    Ying, Qi; Mysliwiec, Mitchell; Kleeman, Michael J

    2004-02-15

    A three-dimensional source-oriented Eulerian air quality model is developed that can predict source contributions to the visibility reduction. Particulate matter and precursor gases from 14 different sources (crustal material, paved road dust, diesel engines, meat cooking, noncatalyst-equipped gasoline engines, catalyst-equipped gasoline engines, high-sulfur fuel, sea salt, refrigerant losses, residential production, animals, soil and fertilizer application, other anthropogenic sources, and background sources) are tracked though a mathematical simulation of emission, chemical reaction, gas-to-particle conversion, transport, and deposition. A visibility model based on Mie theory is modified to use the calculated source contributions to airborne particulate matter size and composition as well as gas-phase pollutant concentrations to quantify total source contributions to visibility impairment. The combined air quality-visibility model is applied to predict source contributions to visibility reduction in southern California for a typical air pollution episode (September 23-25, 1996). The model successfully predicts a severe visibility reduction in the eastern portion of the South Coast Air Basin where the average daytime visibility is measured to be less than 10 km. In the relatively clean coastal portion of the domain, the model successfully predicts that the average daytime visibility is greater than 65 km. Transportation-related sources directly account for approximately 50% of the visibility reduction (diesel engines approximately 15-20%, catalyst-equipped gasoline engines approximately 10-20%, noncatalyst-equipped gasoline engines approximately 3-5%, crustal and paved road dust approximately 5%) in the region with the most severe visibility impairment. Ammonia emissions from animal sources account for approximately 10-15% of the visibility reduction. PMID:14998023

  9. The transport sector as a source of air pollution

    NASA Astrophysics Data System (ADS)

    Colvile, R. N.; Hutchinson, E. J.; Mindell, J. S.; Warren, R. F.

    Transport first became a significant source of air pollution after the problems of sooty smog from coal combustion had largely been solved in western European and North American cities. Since then, emissions from road, air, rail and water transport have been partly responsible for acid deposition, stratospheric ozone depletion and climate change. Most recently, road traffic exhaust emissions have been the cause of much concern about the effects of urban air quality on human health and tropospheric ozone production. This article considers the variety of transport impacts on the atmospheric environment by reviewing three examples: urban road traffic and human health, aircraft emissions and global atmospheric change, and the contribution of sulphur emissions from ships to acid deposition. Each example has associated with it a different level of uncertainty, such that a variety of policy responses to the problems are appropriate, from adaptation through precautionary emissions abatement to cost-benefit analysis and optimised abatement. There is some evidence that the current concern for road transport contribution to urban air pollution is justified, but aircraft emissions should also give cause for concern given that air traffic is projected to continue to increase. Emissions from road traffic are being reduced substantially by the introduction of technology especially three-way catalysts and also, most recently, by local traffic reduction measures especially in western European cities. In developing countries and Eastern Europe, however, there remains the possibility of great increase in car ownership and use, and it remains to be seen whether these countries will adopt measures now to prevent transport-related air pollution problems becoming severe later in the 21st Century.

  10. Air pollution source/receptor relationships in South Coast Air Basin, CA

    SciTech Connect

    Gao, N.

    1993-12-31

    This research project includes the application of some existing receptor models to study the air pollution source/receptor relationships in the South Coast Air Basin of southern California, the development of a new receptor model and the testing and the modifications of some existing models. These existing receptor models used include principal component factor analysis, potential source contribution function analysis, Kohonen`s neural network combined with Prim`s minimal spanning tree, and direct trilinear decomposition followed by a matrix reconstruction. The ambient concentration measurements used in this study are a subset of the data collected during the 1987 field exercise of Southern California Air Quality Study. It consists of a number of gaseous and particulate pollutants analyzed from samples collected by SCAQS samplers at eight sampling sites. Based on the information of emission inventories, meterology and ambient concentrations this receptor modeling study has revealed mechanisms that influence the air quality in SoCAB. Some of the mechanisms affecting the air quality in SoCAB that were revealed during this study include the following aspects. The SO{sub 2} collected at sampling sites is mainly contributed by refineries in the coastal area and the ships equipped with oil-fired boilers off shore. Combustion of fossil fuel by automobiles dominates the emission of NO{sub x} that is subsequently transformed and collected at sampling sites. Electric power plants also contribute HNO{sub 3} to the sampling sites. A large feedlot in the eastern region of SoCAB has been identified as the major source of NH{sub 3}. Possible contributions from other industrial sources such as smelters and incenerators were also revealed. The results of this study also suggest the possibility of DMS (dimethylsuflide) and NH{sub 3} emissions from off-shore sediments that have been contaminated by waste sludge disposal.

  11. Rail gun program

    SciTech Connect

    Fowler, C.M.; Peterson, D.R.

    1980-12-01

    Rail guns are devices that drive projectiles by electromagnetic forces. Ultimate projectile speeds therefore are not limited by hydrodynamic velocities, as is the case with conventional guns. The two-phase rail gun program is described. In both phases, explosively driven flux compression generators (FCGs) are used to supply power to the guns. In the Los Alamos phase, part of the gun itself is explosively compressed and thus serves as a second-stage FCG. Factors affecting gun performance and projectile acceleration and integrity are discussed. The first experiment in the joint phase of the programs is described. Here, a 12.7-mm lexan cube was accelerated to speed about 3 km/s in a 0.9-m-long gun by currents reaching nearly 600 kA over a time of several hundred microseconds. Although the projectile was stressed to several times its static yield strength during acceleration, it was recovered intact.

  12. The impact of an air quality advisory program on voluntary mobile source air pollution reduction

    NASA Astrophysics Data System (ADS)

    Blanken, Peter D.; Dillon, Jennifer; Wismann, Genevieve

    Air pollution from mobile source emissions is a major cause of air quality degradation in the Denver, Colorado, metropolitan area. The projected increase in both population and vehicle miles driven, coupled with the high altitude, predominantly clear skies, and prevalent wintertime temperature inversions aid in the formation and retention of pollutants. The Colorado Department of Public Health issues an air quality advisory daily during the high pollution season (November 1-March 31) with the objective of improving air quality through voluntary driving restrictions and a mandatory wood burning ban. We hypothesized that the advisory had no effect on commuter behavior due to lack of awareness and understanding, lack of alternative means of travel, or lack of concern. We mailed an anonymous, self-administered survey to 1000 commuters living in the cities of Boulder and Westminster, Colorado. Despite the fact that the vast majority of the respondents were aware of the daily advisory (94%), understood what it meant (93%), and heard the posting at least once a day (71%) in time to choose alternative forms of transportation, the advisory did not alter commuter travel. Commuters traveled mainly as the sole occupant of a car and most (76%) never changed the way they commuted based on the daily advisory. Many claimed schedules or work locations did not allow them to use alternative transportation methods. We suggested a practical way to improve the advisory would be to reduce or eliminate public transit fares on poor air quality days.

  13. Gun utopias? Firearm access and ownership in Israel and Switzerland.

    PubMed

    Rosenbaum, Janet E

    2012-02-01

    The 2011 attempted assassination of a US representative renewed the national gun control debate. Gun advocates claim mass-casualty events are mitigated and deterred with three policies: (a) permissive gun laws, (b) widespread gun ownership, (c) and encouragement of armed civilians who can intercept shooters. They cite Switzerland and Israel as exemplars. We evaluate these claims with analysis of International Crime Victimization Survey (ICVS) data and translation of laws and original source material. Swiss and Israeli laws limit firearm ownership and require permit renewal one to four times annually. ICVS analysis finds the United States has more firearms per capita and per household than either country. Switzerland and Israel curtail off-duty soldiers' firearm access to prevent firearm deaths. Suicide among soldiers decreased by 40 per cent after the Israeli army's 2006 reforms. Compared with the United States, Switzerland and Israel have lower gun ownership and stricter gun laws, and their policies discourage personal gun ownership.

  14. An X-Band Gun Test Area at SLAC

    SciTech Connect

    Limborg-Deprey, C.; Adolphsen, C.; Chu, T.S.; Dunning, M.P.; Jobe, R.K.; Jongewaard, E.N.; Hast, C.; Vlieks, A.E.; Wang, F.; Walz, D.R.; Marsh, R.A.; Anderson, S.G.; Hartemann, F.V.; Houck, T.L.; /LLNL, Livermore

    2012-09-07

    The X-Band Test Area (XTA) is being assembled in the NLCTA tunnel at SLAC to serve as a test facility for new RF guns. The first gun to be tested will be an upgraded version of the 5.6 cell, 200 MV/m peak field X-band gun designed at SLAC in 2003 for the Compton Scattering experiment run in ASTA. This new version includes some features implemented in 2006 on the LCLS gun such as racetrack couplers, increased mode separation and elliptical irises. These upgrades were developed in collaboration with LLNL since the same gun will be used in an injector for a LLNL Gamma-ray Source. Our beamline includes an X-band acceleration section which takes the electron beam up to 100 MeV and an electron beam measurement station. Other X-Band guns such as the UCLA Hybrid gun will be characterized at our facility.

  15. Gun utopias? Firearm access and ownership in Israel and Switzerland.

    PubMed

    Rosenbaum, Janet E

    2012-02-01

    The 2011 attempted assassination of a US representative renewed the national gun control debate. Gun advocates claim mass-casualty events are mitigated and deterred with three policies: (a) permissive gun laws, (b) widespread gun ownership, (c) and encouragement of armed civilians who can intercept shooters. They cite Switzerland and Israel as exemplars. We evaluate these claims with analysis of International Crime Victimization Survey (ICVS) data and translation of laws and original source material. Swiss and Israeli laws limit firearm ownership and require permit renewal one to four times annually. ICVS analysis finds the United States has more firearms per capita and per household than either country. Switzerland and Israel curtail off-duty soldiers' firearm access to prevent firearm deaths. Suicide among soldiers decreased by 40 per cent after the Israeli army's 2006 reforms. Compared with the United States, Switzerland and Israel have lower gun ownership and stricter gun laws, and their policies discourage personal gun ownership. PMID:22089893

  16. Gun utopias? Firearm access and ownership in Israel and Switzerland

    PubMed Central

    Rosenbaum, Janet

    2011-01-01

    The 2011 attempted assassination of a US representative renewed the national gun control debate. Gun advocates claim that mass-casualty events are mitigated and deterred with three policies: (1) permissive gun laws, (2) widespread gun ownership, (3) encouragement of armed civilians who can intercept shooters, and cite Switzerland and Israel as exemplars. We evaluate these claims with analysis of International Crime Victimization Survey (ICVS) data and translation of laws and original source material. Swiss and Israeli laws limit firearm ownership and require permit renewal 14 times annually. ICVS analysis finds that the US has more firearms per capita and per household than either country. Switzerland and Israel curtail off-duty soldiers firearm access to prevent firearm deaths. Suicide among soldiers decreased by 40% after the Israeli armys 2006 reforms. Compared with the US, Switzerland and Israel have lower gun ownership and stricter gun laws, and their policies discourage personal gun ownership. PMID:22089893

  17. Survey of SRF guns

    SciTech Connect

    Belomestnykh, S.

    2011-07-25

    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 with 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.

  18. Air Pollution in China: Mapping of Concentrations and Sources

    PubMed Central

    Rohde, Robert A.; Muller, Richard A.

    2015-01-01

    China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO2, NO2, and O3. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widespread across northern and central China and are not limited to major cities or geologic basins. Sources of pollution are widespread, but are particularly intense in a northeast corridor that extends from near Shanghai to north of Beijing. During our analysis period, 92% of the population of China experienced >120 hours of unhealthy air (US EPA standard), and 38% experienced average concentrations that were unhealthy. China’s population-weighted average exposure to PM2.5 was 52 μg/m3. The observed air pollution is calculated to contribute to 1.6 million deaths/year in China [0.7–2.2 million deaths/year at 95% confidence], roughly 17% of all deaths in China. PMID:26291610

  19. Air Pollution in China: Mapping of Concentrations and Sources.

    PubMed

    Rohde, Robert A; Muller, Richard A

    2015-01-01

    China has recently made available hourly air pollution data from over 1500 sites, including airborne particulate matter (PM), SO2, NO2, and O3. We apply Kriging interpolation to four months of data to derive pollution maps for eastern China. Consistent with prior findings, the greatest pollution occurs in the east, but significant levels are widespread across northern and central China and are not limited to major cities or geologic basins. Sources of pollution are widespread, but are particularly intense in a northeast corridor that extends from near Shanghai to north of Beijing. During our analysis period, 92% of the population of China experienced >120 hours of unhealthy air (US EPA standard), and 38% experienced average concentrations that were unhealthy. China's population-weighted average exposure to PM2.5 was 52 μg/m3. The observed air pollution is calculated to contribute to 1.6 million deaths/year in China [0.7-2.2 million deaths/year at 95% confidence], roughly 17% of all deaths in China. PMID:26291610

  20. Sources of volatile organic compounds in Cairo's ambient air.

    PubMed

    Abu-Allaban, M; Lowenthal, D H; Gertler, A W; Labib, M

    2009-10-01

    The greater Cairo area suffers from extreme levels of gas and particulate phase air pollutants. In order to reduce the levels of ambient pollution, the USAID and the Egyptian Environmental Affairs Agency (EEAA) have supported the Cairo Air Improvement Project (CAIP). As part of this project, two intensive ambient monitoring studies were carried out during the period of February 22 to March 4 and October 27 to November 27, 1999. Volatile organic compounds (VOCs) were measured on a 24-h basis at six sampling stations during each of the intensive periods. During the February/March study, samples were collected daily, while in the October/November study samples were collected every other day. The six intensive measurement sites represented background levels, mobile source impacts, industrial impacts, and residential exposure. High levels of NMHC were observed at all locations. NMHC concentrations ranged from 365 ppb C at Helwan to 1,848 ppb C at El Qualaly during winter, 1999 and from 461 ppb C at Kaha to 2,037 ppb C at El Qualaly during fall, 1999. El Qualaly, the site chosen to represent mobile emissions, displayed the highest average NMHC concentrations of any site, by a factor of 2 or more. The highest mobile source contributions were estimated at this site. The major contributors to NMHC at all sites were mobile emissions, lead smelting, and compressed natural gas. PMID:18843549

  1. 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,…

  2. Airborne particle sizes and sources found in indoor air

    NASA Astrophysics Data System (ADS)

    Owen, M. K.; Ensor, D. S.; Sparks, L. E.

    As concern about indoor air quality (IAQ) has grown in recent years, understanding indoor aerosols has become increasingly important so that control techniques may be implemented to reduce damaging health effects and soiling problems. This paper begins with a brief look at the mechanics of deposition in the lungs and the aerosol dynamics that influence particles at all times. This discussion shows that the particle diameters must be known to predict dose or soiling and to determine efficient mitigation techniques. The particle sizes produced by the various indoor sources, as well as unusual aspects of each type of source, must be known so that this process may begin. This paper summarizes the results of a literature search into the sources, sizes and concentrations of indoor particles. There are several types of indoor particles: plant and animal bioaerosols and mineral, combustion and home/personal care aerosols. These types may be produced indoors or outdoors, entering through building openings. The sources may be short term, seasonal or continuous. Particle sizes produced vary from submicrometer to larger than 10 μm. The particles may be toxic or allergenic. This information is presented in a summary table and is discussed in the text.

  3. 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

  4. 14. BUILDING NO. 445, PHYSICS LAB (FORMERLY GUN BAG LOADING), ...

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

    14. BUILDING NO. 445, PHYSICS LAB (FORMERLY GUN BAG LOADING), LOOKING EAST AT SOUTHWEST END OF BUILDING. HVAC EQUIPMENT LOCATED OUTDOORS IN FOREGROUND. DUCTS CONDUCT HOT OR COLD AIR INDOORS. ROUND PIPES ARE INSULATED STEAM LINES. BUILDING NO. 448, ORDNANCE FACILITY, IN BACKGROUND. - Picatinny Arsenal, 400 Area, Gun Bag Loading District, State Route 15 near I-80, Dover, Morris County, NJ

  5. FEATURE 3, LARGE GUN POSITION, SHOWING MULTIPLE COMPARTMENTS, VIEW FACING ...

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

    FEATURE 3, LARGE GUN POSITION, SHOWING MULTIPLE COMPARTMENTS, VIEW FACING SOUTH (with scale stick). - Naval Air Station Barbers Point, Anti-Aircraft Battery Complex-Large Gun Position, East of Coral Sea Road, northwest of Hamilton Road, Ewa, Honolulu County, HI

  6. FEATURE 3, LARGE GUN POSITION, ARMCO HUT (FEATURE 4) IN ...

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

    FEATURE 3, LARGE GUN POSITION, ARMCO HUT (FEATURE 4) IN BACKGROUND, VIEW FACING NORTH. - Naval Air Station Barbers Point, Anti-Aircraft Battery Complex-Large Gun Position, East of Coral Sea Road, northwest of Hamilton Road, Ewa, Honolulu County, HI

  7. ISS Ambient Air Quality: Updated Inventory of Known Aerosol Sources

    NASA Technical Reports Server (NTRS)

    Meyer, Marit

    2014-01-01

    Spacecraft cabin air quality is of fundamental importance to crew health, with concerns encompassing both gaseous contaminants and particulate matter. Little opportunity exists for direct measurement of aerosol concentrations on the International Space Station (ISS), however, an aerosol source model was developed for the purpose of filtration and ventilation systems design. This model has successfully been applied, however, since the initial effort, an increase in the number of crewmembers from 3 to 6 and new processes on board the ISS necessitate an updated aerosol inventory to accurately reflect the current ambient aerosol conditions. Results from recent analyses of dust samples from ISS, combined with a literature review provide new predicted aerosol emission rates in terms of size-segregated mass and number concentration. Some new aerosol sources have been considered and added to the existing array of materials. The goal of this work is to provide updated filtration model inputs which can verify that the current ISS filtration system is adequate and filter lifetime targets are met. This inventory of aerosol sources is applicable to other spacecraft, and becomes more important as NASA considers future long term exploration missions, which will preclude the opportunity for resupply of filtration products.

  8. Air Pollution in Megacities: Sources and Regional/Global Effects

    NASA Astrophysics Data System (ADS)

    Artaxo, P.

    2007-12-01

    Air Pollution in Megacities is increasing significantly in all continents. The socio-economic and health problems are escalating, especially in developing countries. In terms of sources, urban transportation is relevant in most cities, as well as industrial pollution. In Latin American Cities such as Sao Paulo, Mexico City and Santiago, serious governmental efforts are being doing to reduce emissions and effects. Latin America has about 300 cities with population above 300.000 people. In Sao Paulo, the significant increase in the use of ethanol as fuel brings important increase in aldehyde concentrations. In all 3 Megacities, high aerosol concentrations are observed, with clear effects on population health. Large studies on aerosol source apportionment were done in these 3 cities, and detailed results will be presented. Quantification of aerosol sources is a problem, especially in the organic aerosol component that is high in most of Megacities. In Asia and Africa, the problems are similar as in Latin America, and the large emissions from these urban centers are relevant and needs to be taken into account in policies to reduce carbon dioxide emissions.

  9. [Polluting agents and sources of urban air pollution].

    PubMed

    Cocheo, V

    2000-01-01

    This paper is an up-to-date review of the scientific evidence on mechanisms of pollutant generation and health effects for a number of urban air pollutants. The review focuses on main sources and health effect of ozone and photochemical smog, benzene, polycyclic aromatic hydrocarbons, and particulate matter. These agents are "priority pollutants", generated by vehicle traffic, and their regulation is currently being examined by the European Council and the European Commission. The aim is to reach, by the year 2010, values lower than 180 micrograms/m3 for ozone as maximum hourly concentration, 2.5 micrograms/m3 for benzene as an annual average, 93 micrograms/m3 for nitrogen dioxide as 98 degrees percentile of hourly concentrations, 50 micrograms/m3 for particulate as a daily average. The goal can be achieved only by means of immediate interventions on emissions. PMID:11293295

  10. 76 FR 57913 - Amendments to National Emission Standards for Hazardous Air Pollutants for Area Sources: Plating...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-19

    ... Air Pollutants for Area Sources: Plating and Polishing'' which was published on June 20, 2011 (76 FR... AGENCY 40 CFR Part 63 RIN 2060-AQ74 Amendments to National Emission Standards for Hazardous Air... standards for hazardous air pollutants (NESHAP) for the plating and polishing area source category...

  11. Controlling Air Pollution; A Primer on Stationary Source Control Techniques.

    ERIC Educational Resources Information Center

    Corman, Rena

    This companion document to "Air Pollution Primer" is written for the nonexpert in air pollution; however, it does assume a familiarity with air pollution problems. This work is oriented toward providing the reader with knowledge about current and proposed air quality legislation and knowledge about available technology to meet these standards for…

  12. 76 FR 14839 - Delegation of National Emission Standards for Hazardous Air Pollutants for Source Categories...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-18

    ... AGENCY 40 CFR Part 63 Delegation of National Emission Standards for Hazardous Air Pollutants for Source... County Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed... national emission standards for hazardous air pollutants (NESHAP) to the Maricopa County Air...

  13. Modeling internal ballistics of gas combustion guns.

    PubMed

    Schorge, Volker; Grossjohann, Rico; Schönekess, Holger C; Herbst, Jörg; Bockholdt, Britta; Ekkernkamp, Axel; Frank, Matthias

    2016-05-01

    Potato guns are popular homemade guns which work on the principle of gas combustion. They are usually constructed for recreational rather than criminal purposes. Yet some serious injuries and fatalities due to these guns are reported. As information on the internal ballistics of homemade gas combustion-powered guns is scarce, it is the aim of this work to provide an experimental model of the internal ballistics of these devices and to investigate their basic physical parameters. A gas combustion gun was constructed with a steel tube as the main component. Gas/air mixtures of acetylene, hydrogen, and ethylene were used as propellants for discharging a 46-mm caliber test projectile. Gas pressure in the combustion chamber was captured with a piezoelectric pressure sensor. Projectile velocity was measured with a ballistic speed measurement system. The maximum gas pressure, the maximum rate of pressure rise, the time parameters of the pressure curve, and the velocity and path of the projectile through the barrel as a function of time were determined according to the pressure-time curve. The maximum gas pressure was measured to be between 1.4 bar (ethylene) and 4.5 bar (acetylene). The highest maximum rate of pressure rise was determined for hydrogen at (dp/dt)max = 607 bar/s. The muzzle energy was calculated to be between 67 J (ethylene) and 204 J (acetylene). To conclude, this work provides basic information on the internal ballistics of homemade gas combustion guns. The risk of injury to the operator or bystanders is high, because accidental explosions of the gun due to the high-pressure rise during combustion of the gas/air mixture may occur.

  14. Modeling internal ballistics of gas combustion guns.

    PubMed

    Schorge, Volker; Grossjohann, Rico; Schönekess, Holger C; Herbst, Jörg; Bockholdt, Britta; Ekkernkamp, Axel; Frank, Matthias

    2016-05-01

    Potato guns are popular homemade guns which work on the principle of gas combustion. They are usually constructed for recreational rather than criminal purposes. Yet some serious injuries and fatalities due to these guns are reported. As information on the internal ballistics of homemade gas combustion-powered guns is scarce, it is the aim of this work to provide an experimental model of the internal ballistics of these devices and to investigate their basic physical parameters. A gas combustion gun was constructed with a steel tube as the main component. Gas/air mixtures of acetylene, hydrogen, and ethylene were used as propellants for discharging a 46-mm caliber test projectile. Gas pressure in the combustion chamber was captured with a piezoelectric pressure sensor. Projectile velocity was measured with a ballistic speed measurement system. The maximum gas pressure, the maximum rate of pressure rise, the time parameters of the pressure curve, and the velocity and path of the projectile through the barrel as a function of time were determined according to the pressure-time curve. The maximum gas pressure was measured to be between 1.4 bar (ethylene) and 4.5 bar (acetylene). The highest maximum rate of pressure rise was determined for hydrogen at (dp/dt)max = 607 bar/s. The muzzle energy was calculated to be between 67 J (ethylene) and 204 J (acetylene). To conclude, this work provides basic information on the internal ballistics of homemade gas combustion guns. The risk of injury to the operator or bystanders is high, because accidental explosions of the gun due to the high-pressure rise during combustion of the gas/air mixture may occur. PMID:26239103

  15. Remotely controlled spray gun

    NASA Technical Reports Server (NTRS)

    Cunningham, William C. (Inventor)

    1987-01-01

    A remotely controlled spray gun is described in which a nozzle and orifice plate are held in precise axial alignment by an alignment member, which in turn is held in alignment with the general outlet of the spray gun by insert. By this arrangement, the precise repeatability of spray patterns is insured.

  16. Miniature paint-spray gun for recessed areas

    NASA Technical Reports Server (NTRS)

    Vanasse, M. A.

    1968-01-01

    Miniature spray gun regulates paints and other liquids to spray at close range, facilitating spraying of remote or recessed areas. Individual valves for regulating air pressure and paint maximizes atomization for low pressure spraying.

  17. HVAC SYSTEMS AS EMISSION SOURCES AFFECTING INDOOR AIR QUALITY: A CRITICAL REVIEW

    EPA Science Inventory

    The paper discusses results of an evaluation of literature on heating, ventilating, and air-conditioning (HVAC) systems as contaminant emission sources that affect indoor air quality (IAQ). The various literature sources and methods for characterizing HVAC emission sources are re...

  18. 49 CFR 232.107 - Air source requirements and cold weather operations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Air source requirements and cold weather... source requirements and cold weather operations. (a) Monitoring plans for yard air sources. (1) A... to the equipment and territory of that railroad to cover safe train operations during cold...

  19. 49 CFR 232.107 - Air source requirements and cold weather operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Air source requirements and cold weather... source requirements and cold weather operations. (a) Monitoring plans for yard air sources. (1) A... to the equipment and territory of that railroad to cover safe train operations during cold...

  20. 49 CFR 232.107 - Air source requirements and cold weather operations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Air source requirements and cold weather... source requirements and cold weather operations. (a) Monitoring plans for yard air sources. (1) A... to the equipment and territory of that railroad to cover safe train operations during cold...

  1. 49 CFR 232.107 - Air source requirements and cold weather operations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Air source requirements and cold weather... source requirements and cold weather operations. (a) Monitoring plans for yard air sources. (1) A... to the equipment and territory of that railroad to cover safe train operations during cold...

  2. 49 CFR 232.107 - Air source requirements and cold weather operations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Air source requirements and cold weather... source requirements and cold weather operations. (a) Monitoring plans for yard air sources. (1) A... to the equipment and territory of that railroad to cover safe train operations during cold...

  3. Sources of Underwater Sound and Their Characterization.

    PubMed

    Ainslie, Michael A; de Jong, Christ A F

    2016-01-01

    Because of the history of sonar and sonar engineering, the concept of "source level" is widely used to characterize anthropogenic sound sources, but is it useful for sources other than sonar transmitters? The concept and applicability of source level are reviewed for sonar, air guns, explosions, ships, and pile drivers. International efforts toward the harmonization of the terminology for underwater sound and measurement procedures for underwater sound sources are summarized, with particular attention to the initiatives of the International Organization for Standardization.

  4. Electron gun control of smart materials

    NASA Astrophysics Data System (ADS)

    Main, John A.; Nelson, George C.; Martin, Jeffrey W.

    1998-07-01

    Smart material patches are currently an impractical choice in applications requiring fine spatial resolution or control of complex areas. The static nature of electrodes, the conventional choice for control signal application to many smart materials, makes them unsuitable in these instances. To address this issue the use of electron guns as charge sources for smart material control is investigated in this paper. In the electron gun control method the need for separate electrodes and wire leads is eliminated by depositing the control charges directly on the surface of the piezoelectric material. Since piezoelectric materials are dielectrics the charges remain where deposited by the electron gun. The spatial resolution of this control method is as small as the spot size of the electron beam, which in a focused beam can be as small as tens of microns. Large areas can be covered by a single electron gun simply by scanning the beam using deflection plates. Some practical aspects of electron gun control are presented in this paper. A description of an experimental test bed assembled to evaluate electron gun control of PZT-5H is presented, as are results and conceptual models of the system behavior.

  5. Progress on using NEA cathodes in an RF gun

    SciTech Connect

    Fliller, R.P., III; Anderson, T.; Edwards, H.; Bluem, H.; Schultheiss, T.; Sinclair, C.; Huening, M.; /DESY

    2005-05-01

    RF guns have proven useful in multiple accelerator applications, and are an attractive electron source for the ILC. Using a NEA GaAs photocathode in such a gun allows for the production of polarized electron beams. However the lifetime of a NEA cathode in this environment is reduced by ion and electron bombardment and residual gas oxidation. We report progress made with studies to produce a RF gun using a NEA GaAs photocathode to produce polarized electron beams. We discuss simulations of ion back bombardment and attempts to reduce the residual gas pressure in the gun are discussed. Future directions are also discussed.

  6. Open air mineral treatment operations and ambient air quality: assessment and source apportionment.

    PubMed

    Escudero, M; Alastuey, A; Moreno, T; Querol, X; Pérez, P

    2012-11-01

    We present a methodology for evaluating and quantifying the impact of inhalable mineral dust resuspension close to a potentially important industrial point source, in this case an open air plant producing sand, flux and kaolin in the Capuchinos district of Alcañiz (Teruel, NE Spain). PM(10) levels at Capuchinos were initially high (42 μg m(-3) as the annual average with 91 exceedances of the EU daily limit value during 2007) but subsequently decreased (26 μg m(-3) with 16 exceedances in 2010) due to a reduced demand for minerals from the ceramic industry and construction sector during the first stages of the economic crisis. Back trajectory and local wind pattern analyses revealed only limited contribution from exotic PM sources such as African dust intrusions whereas there was clearly a strong link with the mineral stockpiles of the local industry. This link was reinforced by chemical and mineral speciation and source apportionment analysis which showed a dominance of mineral matter (sum of CO(3)(2-), SiO(2), Al(2)O(3), Ca, Fe, K, Mg, P, and Ti: mostly aluminosilicates) which in 2007 contributed 76% of the PM(10) mass (44 μg m(-3) on average). The contribution from Secondary Inorganic Aerosols (SIA, sum of SO(4)(2-), NO(3)(-) and NH(4)(+)) reached 8.4 μg m(-3), accounting for 14% of the PM(10) mass, similar to the amount of calcareous road dust estimated to be present (8 μg m(-3); 13%). Organic matter and elemental carbon contributed 5.3 μg m(-3) (9%) whereas marine aerosol (Na + Cl) levels were minor with an average concentration of 0.4 μg m(-3) (1% of the PM(10) mass). Finally, chemical and mineralogical analysis of stockpile samples and comparison with filter samples confirmed the local industry to be the major source of ambient PM(10) in the area.

  7. Intra-urban biomonitoring: Source apportionment using tree barks to identify air pollution sources.

    PubMed

    Moreira, Tiana Carla Lopes; de Oliveira, Regiani Carvalho; Amato, Luís Fernando Lourenço; Kang, Choong-Min; Saldiva, Paulo Hilário Nascimento; Saiki, Mitiko

    2016-05-01

    It is of great interest to evaluate if there is a relationship between possible sources and trace elements using biomonitoring techniques. In this study, tree bark samples of 171 trees were collected using a biomonitoring technique in the inner city of São Paulo. The trace elements (Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, Rb, S, Sr and Zn) were determined by the energy dispersive X-ray fluorescence (EDXRF) spectrometry. The Principal Component Analysis (PCA) was applied to identify the plausible sources associated with tree bark measurements. The greatest source was vehicle-induced non-tailpipe emissions derived mainly from brakes and tires wear-out and road dust resuspension (characterized with Al, Ba, Cu, Fe, Mn and Zn), which was explained by 27.1% of the variance, followed by cement (14.8%), sea salt (11.6%) and biomass burning (10%), and fossil fuel combustion (9.8%). We also verified that the elements related to vehicular emission showed different concentrations at different sites of the same street, which might be helpful for a new street classification according to the emission source. The spatial distribution maps of element concentrations were obtained to evaluate the different levels of pollution in streets and avenues. Results indicated that biomonitoring techniques using tree bark can be applied to evaluate dispersion of air pollution and provide reliable data for the further epidemiological studies.

  8. Intra-urban biomonitoring: Source apportionment using tree barks to identify air pollution sources.

    PubMed

    Moreira, Tiana Carla Lopes; de Oliveira, Regiani Carvalho; Amato, Luís Fernando Lourenço; Kang, Choong-Min; Saldiva, Paulo Hilário Nascimento; Saiki, Mitiko

    2016-05-01

    It is of great interest to evaluate if there is a relationship between possible sources and trace elements using biomonitoring techniques. In this study, tree bark samples of 171 trees were collected using a biomonitoring technique in the inner city of São Paulo. The trace elements (Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, Rb, S, Sr and Zn) were determined by the energy dispersive X-ray fluorescence (EDXRF) spectrometry. The Principal Component Analysis (PCA) was applied to identify the plausible sources associated with tree bark measurements. The greatest source was vehicle-induced non-tailpipe emissions derived mainly from brakes and tires wear-out and road dust resuspension (characterized with Al, Ba, Cu, Fe, Mn and Zn), which was explained by 27.1% of the variance, followed by cement (14.8%), sea salt (11.6%) and biomass burning (10%), and fossil fuel combustion (9.8%). We also verified that the elements related to vehicular emission showed different concentrations at different sites of the same street, which might be helpful for a new street classification according to the emission source. The spatial distribution maps of element concentrations were obtained to evaluate the different levels of pollution in streets and avenues. Results indicated that biomonitoring techniques using tree bark can be applied to evaluate dispersion of air pollution and provide reliable data for the further epidemiological studies. PMID:26995269

  9. Comparison of a laboratory and a production coating spray gun with respect to scale-up.

    PubMed

    Mueller, Ronny; Kleinebudde, Peter

    2007-01-19

    A laboratory spray gun and a production spray gun were investigated in a scale-up study. Two Schlick spray guns, which are equipped with a new antibearding cap, were used in this study. The influence of the atomization air pressure, spray gun-to tablet bed distance, polymer solution viscosity, and spray rate were analyzed in a statistical design of experiments. The 2 spray guns were compared with respect to the spray width and height, droplet size, droplet velocity, and spray density. The droplet size, velocity, and spray density were measured with a Phase Doppler Particle Analyzer. A successful scale-up of the atomization is accomplished if similar droplet sizes, droplet velocities, and spray densities are achieved in the production scale as in the laboratory scale. This study gives basic information for the scale-up of the settings from the laboratory spray gun to the production spray gun. Both spray guns are highly comparable with respect to the droplet size and velocity. The scale-up of the droplet size should be performed by an adjustment of the atomization air pressure. The scale-up of the droplet velocity should be performed by an adjustment of the spray gun to tablet bed distance. The presented statistical model and surface plots are convenient and powerful tools for scaling up the spray settings if the spray gun is changed from laboratory spray gun to the production spray gun.

  10. High Velocity Gas Gun

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A video tape related to orbital debris research is presented. The video tape covers the process of loading a High Velocity Gas Gun and firing it into a mounted metal plate. The process is then repeated in slow motion.

  11. LARGE-SCALE PREDICTIONS OF MOBILE SOURCE CONTRIBUTIONS TO CONCENTRATIONS OF TOXIC AIR POLLUTANTS

    EPA Science Inventory

    This presentation shows concentrations and deposition of toxic air pollutants predicted by a 3-D air quality model, the Community Multi Scale Air Quality (CMAQ) modeling system. Contributions from both on-road and non-road mobile sources are analyzed.

  12. 77 FR 41146 - Delegation of National Emission Standards for Hazardous Air Pollutants for Source Categories...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-12

    ... AGENCY 40 CFR Part 63 Delegation of National Emission Standards for Hazardous Air Pollutants for Source.... SUMMARY: Pursuant to section 112(l) of the Clean Air Act as amended in 1990, EPA is proposing to grant delegation of specific national emission standards for hazardous air pollutants (NESHAP) to the Gila...

  13. 75 FR 8888 - Delegation of National Emission Standards for Hazardous Air Pollutants for Source Categories...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-26

    ... AGENCY 40 CFR Part 63 Delegation of National Emission Standards for Hazardous Air Pollutants for Source...). ACTION: Proposed rule. SUMMARY: Pursuant to section 112(l) of the 1990 Clean Air Act, EPA granted delegation of specific national emission standards for hazardous air pollutants (NESHAP) to the...

  14. Indoor air: Contemporary sources, exposures and global implications

    NASA Astrophysics Data System (ADS)

    Morawska, Lidia; Salthammer, Tunga

    2015-04-01

    Recent 'Global Burden of Disease' studies have provided quantitative evidence of the significant role air pollution plays as a human health risk factor (Lim et al., The Lancet, 380: 2224-2260, 2012). Tobacco smoke, including second hand smoke, household air pollution from solid fuels and ambient particulate matter are among the top risks, leading to lower life expectancy around the world.

  15. Temperature and Humidity Independent Control Research on Ground Source Heat Pump Air Conditioning System

    NASA Astrophysics Data System (ADS)

    Chen, G.; Wang, L. L.

    Taking green demonstration center building air conditioning system as an example, this paper presents the temperature and humidity independent control system combined with ground source heat pump system, emphasis on the design of dry terminal device system, fresh air system and ground source heat pump system.

  16. Analysis of mobile source air toxics (MSATs)–Near-Road VOC and carbonyl concentrations

    EPA Science Inventory

    Exposures to mobile source air toxics (MSATs) have been associated with numerous adverse health effects. While thousands of air toxic compounds are emitted from mobile sources, a subset of compounds are considered high priority due to their significant contribution to cancer and...

  17. Panama Canal Expansion Illustrates Need for Multimodal Near-Source Air Quality Assessment

    EPA Science Inventory

    The compelling issue raised is potential major changes in goods movement due to the Panama Canal expansion and considerations for near-source air quality. Near-source air quality may be affected both at near-port areas as well as along the freight transportation corridor.

  18. Creativity under the gun.

    PubMed

    Amabile, Teresa M; Hadley, Constance N; Kramer, Steven J

    2002-08-01

    If you're like most managers, you've worked with people who swear they do their most creative work under tight deadlines. You may use pressure as a management technique, believing it will spur people on to great leaps of insight. You may even manage yourself this way. If so, are you right? Not necessarily, these researchers say. There are instances where ingenuity flourishes under extreme time pressure--for instance, a NASA team within hours comes up with a primitive but effective fix for the failing air filtration system aboard Apollo 13. But when creativity is under the gun, it usually ends up getting killed, the authors say. They recently took a close look at how people experience time pressure, collecting and analyzing more than 9,000 daily diary entries from individuals who were working on projects that required high levels of creativity and measuring their ability to innovate under varying levels of time pressure. The authors describe common characteristics of time pressure and outline four working environments under which creativity may or may not flourish. High-pressure days that still yield creativity are full of focus and meaningful urgency--people feel like they are on a mission. High-pressure days that yield no creativity lack such focus--people feel like they are on a treadmill, forced to switch gears often. On low-pressure days that yield creativity, people feel like they are on an expedition--exploring ideas rather than just identifying problems. And on low-pressure days that yield no creative thinking, people work on autopilot--doing their jobs without engaging too deeply. Managers should avoid extreme time pressure when possible; after all, complex cognitive processing takes time. For when they can't, the authors suggest ways to mollify its effects. PMID:12195920

  19. Creativity under the gun.

    PubMed

    Amabile, Teresa M; Hadley, Constance N; Kramer, Steven J

    2002-08-01

    If you're like most managers, you've worked with people who swear they do their most creative work under tight deadlines. You may use pressure as a management technique, believing it will spur people on to great leaps of insight. You may even manage yourself this way. If so, are you right? Not necessarily, these researchers say. There are instances where ingenuity flourishes under extreme time pressure--for instance, a NASA team within hours comes up with a primitive but effective fix for the failing air filtration system aboard Apollo 13. But when creativity is under the gun, it usually ends up getting killed, the authors say. They recently took a close look at how people experience time pressure, collecting and analyzing more than 9,000 daily diary entries from individuals who were working on projects that required high levels of creativity and measuring their ability to innovate under varying levels of time pressure. The authors describe common characteristics of time pressure and outline four working environments under which creativity may or may not flourish. High-pressure days that still yield creativity are full of focus and meaningful urgency--people feel like they are on a mission. High-pressure days that yield no creativity lack such focus--people feel like they are on a treadmill, forced to switch gears often. On low-pressure days that yield creativity, people feel like they are on an expedition--exploring ideas rather than just identifying problems. And on low-pressure days that yield no creative thinking, people work on autopilot--doing their jobs without engaging too deeply. Managers should avoid extreme time pressure when possible; after all, complex cognitive processing takes time. For when they can't, the authors suggest ways to mollify its effects.

  20. Low Emittance Guns for the ILC Polarized Electron Beam

    SciTech Connect

    Clendenin, J.E.; Brachmann, A.; Ioakeimidi, K.; Kirby, R.E.; Maruyama, T.; Miller, R.H.; Wang, J.W.; Zhou, F.; /SLAC

    2006-12-01

    Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of {ge}200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while {ge}500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns.

  1. Low Emittance Guns for the ILC Polarized Electron Beam

    SciTech Connect

    Clendenin, J. E.; Brachmann, A.; Ioakeimidi, K.; Kirby, R. E.; Maruyama, T.; Miller, R. H.; Wang, J. W.; Zhou, F.

    2007-06-13

    Polarized electron beams generated by DC guns are routinely available at several accelerators including JLAB, Mainz and SLAC. These guns operate with a cathode bias on the order of -100 kV. To minimize space charge effects, relatively long bunches are generated at the gun and then compressed longitudinally external to the gun just before and during initial acceleration. For linear colliders, this compression is accomplished using a combination of rf bunchers. For the basic design of the International Linear Collider (ILC), a 120 kV DC photocathode gun is used to produce a series of nanosecond bunches that are each compressed by two sub-harmonic bunchers (SHBs) followed by an L-band buncher and capture section. The longitudinal bunching process results in a significantly higher emittance than produced by the gun alone. While high-energy experiments using polarized beams are not generally sensitive to the source emittance, there are several benefits to a lower source emittance including a simpler more efficient injector system and a lower radiation load during transport especially at bends as at the damping ring. For the ILC, the SHBs could be eliminated if the voltage of the gun is raised sufficiently. Simulations using the General Particle Tracer (GPT) package indicate that a cathode bias voltage of {>=}200 kV should allow both SHBs to be operated at 433 or even 650 MHz, while {>=}500 kV would be required to eliminate the SHBs altogether. Simulations can be used to determine the minimum emittance possible if the injector is designed for a given increased voltage. A possible alternative to the DC gun is an rf gun. Emittance compensation, routinely used with rf guns, is discussed for higher-voltage DC guns.

  2. Electromagnetic configurations of rail guns

    NASA Astrophysics Data System (ADS)

    Fat'yanov, O. V.; Ostashev, V. E.; Lopyrev, A. N.; Ul'Yanov, A. V.

    1993-06-01

    Some problems associated with the electromagnetic acceleration of macrobodies in a rail gun are examined. An approach to the design of rail gun configurations is proposed, and some basic rail gun schemes are synthesized. The alternative rail gun schemes are compared in terms of electrode potential and stability of the electrode gap with respect to parasitic current shunting. The effect of the ohmic resistance of the electrodes and of the additional magnetization field on the spatial structure of the discharge in the rail gun channel is discussed. A classification of rail gun modifications is presented.

  3. Dynamic Radioactive Source for Evaluating and Demonstrating Time-dependent Performance of Continuous Air Monitors.

    PubMed

    McLean, Thomas D; Moore, Murray E; Justus, Alan L; Hudston, Jonathan A; Barbé, Benoît

    2016-11-01

    Evaluation of continuous air monitors in the presence of a plutonium aerosol is time intensive, expensive, and requires a specialized facility. The Radiation Protection Services Group at Los Alamos National Laboratory has designed a Dynamic Radioactive Source, intended to replace plutonium aerosol challenge testing. The Dynamic Radioactive Source is small enough to be inserted into the sampler filter chamber of a typical continuous air monitor. Time-dependent radioactivity is introduced from electroplated sources for real-time testing of a continuous air monitor where a mechanical wristwatch motor rotates a mask above an alpha-emitting electroplated disk source. The mask is attached to the watch's minute hand, and as it rotates, more of the underlying source is revealed. The measured alpha activity increases with time, simulating the arrival of airborne radioactive particulates at the air sampler inlet. The Dynamic Radioactive Source allows the temporal behavior of puff and chronic release conditions to be mimicked without the need for radioactive aerosols. The new system is configurable to different continuous air monitor designs and provides an in-house testing capability (benchtop compatible). It is a repeatable and reusable system and does not contaminate the tested air monitor. Test benefits include direct user control, realistic (plutonium) aerosol spectra, and iterative development of continuous air monitor alarm algorithms. Data obtained using the Dynamic Radioactive Source has been used to elucidate alarm algorithms and to compare the response time of two commercial continuous air monitors. PMID:27682903

  4. MODELING POPULATION EXPOSURES TO OUTDOOR SOURCES OF HAZARDOUS AIR POLLUTANTS

    EPA Science Inventory

    Accurate assessment of human exposures is an important part of environmental health effects research. However, most air pollution epidemiology studies rely upon imperfect surrogates of personal exposures, such as information based on available central-site outdoor concentration ...

  5. Electron gun system for NSC KIPT linac

    NASA Astrophysics Data System (ADS)

    Zhou, Zu-Sheng; He, Da-Yong; Chi, Yun-Long

    2014-06-01

    In the NSC KIPT linac, a neutron source based on a subcritical assembly driven by a 100 MeV/100 kW electron linear accelerator is under design and development. The linear accelerator needs a new high current electron gun. In this paper, the physical design, mechanical fabrication and beam test of this new electron gun are described. The emission current is designed to be higher than 2 A for the pulse width of 3 μs with repetition rate of 50 Hz. The gun will operate with a DC high voltage power supply that can provide a high voltage up to 150 kV. Computer simulations and optimizations have been carried out in the design stage, including the gun geometry and beam transport line. The test results of high voltage conditioning and beam test are presented. The operation status of the electron gun system is also included. The basic test results show that the design, manufacture, and operation of the new electron system are basically successful.

  6. 40 CFR 49.138 - Rule for the registration of air pollution sources and the reporting of emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 10 § 49.138 Rule for the registration of air pollution sources and the reporting of emissions. (a... maintain a current and accurate record of air pollution sources and their emissions within the Indian... part 71 source or an air pollution source that is subject to a standard established under section...

  7. 40 CFR 49.138 - Rule for the registration of air pollution sources and the reporting of emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Reservations in Epa Region 10 § 49.138 Rule for the registration of air pollution sources and the reporting of... develop and maintain a current and accurate record of air pollution sources and their emissions within the... operates a part 71 source or an air pollution source that is subject to a standard established...

  8. 40 CFR 49.138 - Rule for the registration of air pollution sources and the reporting of emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Reservations in Epa Region 10 § 49.138 Rule for the registration of air pollution sources and the reporting of... develop and maintain a current and accurate record of air pollution sources and their emissions within the... operates a part 71 source or an air pollution source that is subject to a standard established...

  9. 40 CFR 49.138 - Rule for the registration of air pollution sources and the reporting of emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Reservations in Epa Region 10 § 49.138 Rule for the registration of air pollution sources and the reporting of... develop and maintain a current and accurate record of air pollution sources and their emissions within the... operates a part 71 source or an air pollution source that is subject to a standard established...

  10. 40 CFR 49.138 - Rule for the registration of air pollution sources and the reporting of emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Reservations in Epa Region 10 § 49.138 Rule for the registration of air pollution sources and the reporting of... develop and maintain a current and accurate record of air pollution sources and their emissions within the... operates a part 71 source or an air pollution source that is subject to a standard established...

  11. Injuries due to firearms and air guns among U.S. military members not participating in overseas combat operations, 2002-2011.

    PubMed

    2012-09-01

    During 2002-2011, active component U.S. service members sustained 4,657 firearm-related injuries in circumstances other than deployment to the wars in Iraq/Afghanistan; 35 percent of the injuries were fatal. The highest firearm-related injury rates reflected service members in law enforcement/security and combat occupations. Of fatal injuries, 28 percent and 24 percent were suicides and homicides, respectively; among service members 30 and older, 84 percent of noncombat firearm-related deaths were suicides and 14 percent were homicides. In circumstances other than war, rates of both fatal and nonfatal firearm- related injuries are much lower among military members than civilian males aged 18-44. During the period, rates of nonfatal firearm-related injuries among non-deployed military members increased sharply, peaking in 2008. The trend reflects that among U.S. civilian males aged 18-44. However, firearm-related fatality rates were stable among civilians but increased among military members. The increase in rates of firearm-related fatalities among non-deployed military members reflects the increase in rates of suicides by firearms. Rates of injuries due to BB, pellet or paintball guns also increased during the period.

  12. The Mystery of the Gun Turret in the Desert

    SciTech Connect

    Hoffman, R. D.

    2015-11-30

    The mystery of the gun turret in the desert began with an ingenious idea: to develop a reusable open-air line of sight diagnostic device to support LLNL’s early nuclear weapons development efforts. Obtained from the Mare Island Navy Shipyard (MINS) in January 1957, the gun turret traveled by ship to the Naval Construction Battalion base at Port Hueneme, California, and then by truck to Area 2 in the Yucca Flats valley at the Nevada Nuclear Security Site (NNSS).

  13. Electromagnetic targeting of guns

    SciTech Connect

    Pogue, E.W.; Boat, R.M.; Holden, D.N.; Lopez, J.R.

    1996-10-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Electromagnetic pulse (EMP) signals produced from explosives being fired have been reported in the literature for fifty years. When a gun is fired it produces an EMP muzzle blast signal. The strength and nature of these signals was first analyzed in the early 1970s, while the results were interesting, no follow-up studies were conducted. With modern detection and signal processing technology, we believe that these signals could be used to instantaneously locate guns of virtually all calibers as they fire. The objective of our one-year project was to establish the basic nature of these signals and their utility in the concept of electromagnetic targeting of guns.

  14. Mole gun injury.

    PubMed

    Pistré, V; Rezzouk, J

    2013-09-01

    A mole gun is a weapon, which is used to trap and kill moles. This report provides an overview of the state of knowledge of mole gun injuries, comparable to blast injuries caused by fireworks, explosive or gunshot. Over a 2-year period, the authors reported their experience with ten hand injuries caused by mole gun. Radial side of the hand was often concerned, particularly the thumb. The authors explain their choices in the management of such lesions. Surgery was performed primarily and a large debridement currently seemed to offer the best outcome for the patient. Blast, crush, burns and lacerations may explain the higher rate of amputation to the digits. A long period of physiotherapy, specifically of the hand, was needed before the patient could return to work. This ballistic hand trauma encountered by surgeons requires knowledge and understanding of these injuries. It should be in accordance with firearms law because of severe injuries encountered and possible lethal wounds. PMID:23746826

  15. Mole gun injury.

    PubMed

    Pistré, V; Rezzouk, J

    2013-09-01

    A mole gun is a weapon, which is used to trap and kill moles. This report provides an overview of the state of knowledge of mole gun injuries, comparable to blast injuries caused by fireworks, explosive or gunshot. Over a 2-year period, the authors reported their experience with ten hand injuries caused by mole gun. Radial side of the hand was often concerned, particularly the thumb. The authors explain their choices in the management of such lesions. Surgery was performed primarily and a large debridement currently seemed to offer the best outcome for the patient. Blast, crush, burns and lacerations may explain the higher rate of amputation to the digits. A long period of physiotherapy, specifically of the hand, was needed before the patient could return to work. This ballistic hand trauma encountered by surgeons requires knowledge and understanding of these injuries. It should be in accordance with firearms law because of severe injuries encountered and possible lethal wounds.

  16. 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.

  17. Unbalanced field RF electron gun

    SciTech Connect

    Hofler, Alicia

    2013-11-12

    A design for an RF electron gun having a gun cavity utilizing an unbalanced electric field arrangement. Essentially, the electric field in the first (partial) cell has higher field strength than the electric field in the second (full) cell of the electron gun. The accompanying method discloses the use of the unbalanced field arrangement in the operation of an RF electron gun in order to accelerate an electron beam.

  18. Air stripping of contaminated water sources - air emissions and controls. Final report

    SciTech Connect

    Vancit, M.A.; Howle, R.H.; Herndon, D.J.; Shareef, S.A.

    1987-08-01

    Air-stripping towers are being used to remove low concentrations of organic contaminants from water. The report describes the technology and methods used to control air pollution resulting from this procedure. The cost of the controls is presented along with other positive and negative impacts of the technology.

  19. AIRBORNE PARTICLE SIZES AND SOURCES FOUND IN INDOOR AIR

    EPA Science Inventory

    As concern about indoor air quality (IAQ) has grown in recent years, understanding indoor aerosols has become increasingly important so that control techniques may be implemented to reduce damaging health effects and soiling problems. This paper begins with a brief look at the me...

  20. 75 FR 31895 - National Emission Standards for Hazardous Air Pollutants for Area Sources: Industrial, Commercial...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-04

    ... implemented this provision in 1999 in the Integrated Urban Air Toxics Strategy (Strategy), (64 FR 38715, July... combustion. See 63 FR 17849. We listed these source categories under CAA section 112(c)(6) based on the.... Both source categories were included in the area source list published on July 19, 1999 (64 FR...

  1. Hot hollow cathode gun assembly

    DOEpatents

    Zeren, J.D.

    1983-11-22

    A hot hollow cathode deposition gun assembly includes a hollow body having a cylindrical outer surface and an end plate for holding an adjustable heat sink, the hot hollow cathode gun, two magnets for steering the plasma from the gun into a crucible on the heat sink, and a shutter for selectively covering and uncovering the crucible.

  2. Children, Youth, and Gun Violence.

    ERIC Educational Resources Information Center

    Behrman, Richard E., Ed.

    2002-01-01

    This collection of articles summarizes knowledge and research about how gun violence affects children and youth and discusses which policies hold promise for reducing youth gun violence. The papers are: (1) "Statement of Purpose" (Richard E. Behrman); "Children, Youth, and Gun Violence: Analysis and Recommendations" (Kathleen Reich, Patti L.…

  3. Vacuum vapor deposition gun assembly

    DOEpatents

    Zeren, Joseph D.

    1985-01-01

    A vapor deposition gun assembly includes a hollow body having a cylindrical outer surface and an end plate for holding an adjustable heat sink, a hot hollow cathode gun, two magnets for steering the plasma from the gun into a crucible on the heat sink, and a shutter for selectively covering and uncovering the crucible.

  4. Glue Guns: Aiming for Safety

    ERIC Educational Resources Information Center

    Roy, Ken

    2010-01-01

    While glue guns are very useful, there are safety issues. Regardless of the temperature setting, glue guns can burn skin. The teacher should demonstrate and supervise the use of glue guns and have a plan should a student get burned. There should be an initial first aid protocol in place, followed by a visit to the school nurse. An accident report…

  5. Modeling exposure close to air pollution sources in naturally ventilated residences: association of turbulent diffusion coefficient with air change rate.

    PubMed

    Cheng, Kai-Chung; Acevedo-Bolton, Viviana; Jiang, Ruo-Ting; Klepeis, Neil E; Ott, Wayne R; Fringer, Oliver B; Hildemann, Lynn M

    2011-05-01

    For modeling exposure close to an indoor air pollution source, an isotropic turbulent diffusion coefficient is used to represent the average spread of emissions. However, its magnitude indoors has been difficult to assess experimentally due to limitations in the number of monitors available. We used 30-37 real-time monitors to simultaneously measure CO at different angles and distances from a continuous indoor point source. For 11 experiments involving two houses, with natural ventilation conditions ranging from <0.2 to >5 air changes per h, an eddy diffusion model was used to estimate the turbulent diffusion coefficients, which ranged from 0.001 to 0.013 m² s⁻¹. The model reproduced observed concentrations with reasonable accuracy over radial distances of 0.25-5.0 m. The air change rate, as measured using a SF₆ tracer gas release, showed a significant positive linear correlation with the air mixing rate, defined as the turbulent diffusion coefficient divided by a squared length scale representing the room size. The ability to estimate the indoor turbulent diffusion coefficient using two readily measurable parameters (air change rate and room dimensions) is useful for accurately modeling exposures in close proximity to an indoor pollution source.

  6. Negative air ions as a source of superoxide

    NASA Astrophysics Data System (ADS)

    Goldstein, Naum I.; Goldstein, Roman N.; Merzlyak, Mark N.

    1992-06-01

    The physico-chemical characteristics and possible formation mechanisms of negative air ions are considered. It was found that the products of oxygen and nitrogen negative ionization reduce ferricytochrome c and nitroblue tetrazolium, and that these reactions were inhibited by superoxide dismutase. The interaction of negatively ionized oxygen with water led to hydrogen peroxide accumulation, which was inhibited by tetranitromethane or catalase. Nitrogen ionization under these conditions caused the formation of the hydrated electron e{aq/—} and the superoxide anion O{2/—}. The data obtained indicate that the biological activity of negative air ions may be dependent on superoxide. The generation of reactive oxygen ions in the gas phase and also at a gas/water interface is described. A scheme for superoxide production under oxygen and nitrogen ionization is proposed.

  7. Improved DC Gun and Insulator Assembly

    SciTech Connect

    Neubauer, Michael; Johnson, Rolland P

    2015-01-11

    Many user facilities such as synchrotron radiation light sources and free electron lasers rely on DC high voltage photoguns with internal field gradients as high as 10 to 15 MV/m. These high gradients often lead to field emission which poses serious problems for the photocathode used to generate the electron beam and the ceramic insulators used to bias the photocathode at high voltage. Ceramic insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic causing a buildup of charge and eventual puncture, and also because large diameter ceramics are difficult to braze reliably. The lifetimes of photo cathodes inside high current DC guns exhibiting field emission are limited to less than a hundred hours. Reducing the surface gradients on the metals reduces the field emission, which serves to maintain the required ultrahigh vacuum condition. A novel gun design with gradients around 5 MV/m and operating at 350 kV, a major improvement over existing designs, was proposed that allows for the in-situ replacement of photo cathodes in axially symmetric designs using inverted ceramics. In this project, the existing JLAB CEBAF asymmetric gun design with an inverted ceramic support was modeled and the beam dynamics characterized. An improved structure was designed that reduces the surface gradients and improves the beam optics. To minimize the surface gradients, a number of electrostatic gun designs were studied to determine the optimum configuration of the critical electrodes within the gun structure. Coating experiments were carried out to create a charge dissipative coating for cylindrical ceramics. The phase II proposal, which was not granted, included the design and fabrication of an axially symmetric DC Gun with an inverted ceramic that would operate with less than 5 MV/m at 350 kV and would be designed with an in-situ replaceable photo-cathode.

  8. Operational Experience with the Nb/Pb SRF Photoelectron Gun

    SciTech Connect

    Kamps, T; Barday, R; Jankowiak, A; Knoblock, J; Kugeler, O; Matveenko, A N; Neumann, A; Quast, T; Rudolph, J; Schubert, S G; Volker, J; Kneisel, P; Nietubyc, R; Sekutowicz, J K; Smedley, J; Teichert, J; Volkov, V; Will, I

    2012-07-01

    SRF photoelectron guns offer the promise of high brightness, high average current beam production for the next generation of accelerator driven light sources such as free electron lasers, THz radiation sources or energy-recovery linac driven synchrotron radiation sources. In a first step a fully superconducting RF (SRF) photoelectron gun is under development by a collaboration between HZB, DESY, JLAB, BNL and NCBJ. The aim of the experiment is to understand and improve the performance of a Nb SRF gun cavity coated with a small metallic Pb cathode film on the cavity backplane. This paper describes the highlights from the commissioning and beam parameter measurements. The main focus is on lessons learned from operation of the SRF gun.

  9. Biodiesel and Cold Temperature Effect on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

    EPA Science Inventory

    Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

  10. Biodiesel and Cold Temperature Effects on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

    EPA Science Inventory

    Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

  11. Air Quality Modeling Needs for Exposure Assessment form the Source-To-Outcome Perspective

    EPA Science Inventory

    Humans are exposed continuously to mixtures of air pollutants. The compositions of these mixtures vary with time and location and their components originate from many types of sources, both local and distant, including industrial facilities, vehicles, consumer products, and more....

  12. Assessment of Near-Source Air Pollution at a Fine Spatial Scale Utilizing Mobile Monitoring Approach

    EPA Science Inventory

    Mobile monitoring is an emerging strategy to characterize spatially and temporally variable air pollution in areas near sources. EPA’s Geospatial Monitoring of Air Pollution (GMAP) vehicle – an all-electric vehicle measuring real-time concentrations of particulate and gaseous po...

  13. Analysis of Mobile Source Air Toxics (MSATS)–Near-Road VOC and CarbonylConcentrations

    EPA Science Inventory

    This presentation examines data from a year-long study of measured near-road mobile source air toxic (MSAT) concentrations and compares these data with modeled 2005 National Air Toxic Assessment (NATA) results. Field study measurements were collected during a field campaign in ...

  14. Assessment of Near-Source Air Pollution at a Fine Spatial Scale Utilizing Mobile Monitoring Approach

    EPA Science Inventory

    Mobile monitoring is an emerging strategy to characterize spatially and temporally variable air pollution in areas near sources. EPA’s Geospatial Monitoring of Air Pollution (GMAP) vehicle – an all-electric vehicle measuring real-time concentrations of particulate an...

  15. Giving Up the Gun.

    ERIC Educational Resources Information Center

    LaRue, Robert D.

    1989-01-01

    Provides a model lesson from the book "Science/Technology/Society: Model Lessons for Secondary Social Studies Classes." Outlines Japan's campaign in the seventeenth and eighteenth centuries to rid itself of guns and return to swords. Provides background information and student handouts. (RW)

  16. Gyrotron gun study report

    NASA Astrophysics Data System (ADS)

    Baird, J. M.; Attard, A. C.

    1982-09-01

    The purpose of the program was to explore new gyrotron gun configurations and to design a low velocity spread replacement gun for the NRL 35 GHz gyro-TWT. The specific beam forming techniques which were studied were magnetic field reversal, transverse magnetic field kicker, and single anode (diode-like) Magnetron Injection Guns (MIGs). This report contains a summary of our work in each of these areas as well as a description of the new MIG design for the gyro-TWT. Gyrotron oscillators and amplifiers require an entirely different type of electron gun design than those normally used in conventional tube designs. The ideal beam must not only have the proper geometry to maximize the rf interaction with the selected waveguide circuit mode, but also, for maximum efficiency, there are two additional requirements: (1) the transverse velocity of the electrons must exceed the longitudinal velocity by a typical factor of 1.5 to 2 (intermixed helical electron trajectories are allowed); and (2) the spread in the longitudinal velocities must be small (on the order of 10-20% for oscillators, 2-5% for amplifiers). Several methods for producing gyrotron beams have been investigated, and most likely different approaches will be necessary for differing power levels and velocity spread requirements.

  17. Gun Dealers, USA.

    ERIC Educational Resources Information Center

    Duker, Laurie; And Others

    In the United States, more than 11,500 adolescents' and young adults' lives are taken each year by firearms. Although Federal law prohibits minors from purchasing handguns, they typically get them by asking someone of legal age (18 years or older) to purchase them from one of the 256,771 Federally licensed gun dealers. This pamphlet answers…

  18. Gun control saves lives.

    PubMed

    Matzopoulos, Richard

    2016-06-01

    Reducing firearm mortality by means of stricter gun control is one of the most important short- to medium-term measures to address the burden of violence in South Africa, while longer-term interventions and policy measures take effect. PMID:27245735

  19. Radar gun hazards

    SciTech Connect

    Not Available

    1991-12-20

    Radar guns - hand-held units used by the law to nail speeders - have been in use since the early '60s. Now they've been accused of causing cancer. Police officers in several states have so far filed eight suits against the manufacturer, claiming that they have contracted rare forms of cancer, such as of the eyelid and the testicle, from frequent proximity to the devices. Spurred by concerns expressed by police groups, researchers at the Rochester Institute of Technology are conducting what they believe to be the first research of its kind in the nation. Last month psychologist John Violanti, an expert in policy psychology and health, sent out a one-page survey to 6,000 active and retired police officers in New York State, asking them about their health and their use of radar guns. Violanti says melanoma, leukemia, and lymph node cancer may be linked to these as well as other electromagnetic devices. The Food and Drug Administration earlier this year issued a warning about radar guns, telling users not to operate them closer than 6 inches from the body. But this may not be a sufficient safeguard since the instruments can give off crisscrossing wave emissions within a police vehicle. The survey will be used to help determine if it would be safer to mount the guns, which are currently either hand-held or mounted on dashboards, outside troopers' cars.

  20. The Rail Gun.

    ERIC Educational Resources Information Center

    Stewart, Gay B.

    1996-01-01

    Presents a rail gun demonstration that addresses a broad group of educational goals in introductory electricity and magnetism. Uses a battery-powered circuit consisting of a movable conductor placed across two conducting rails in a magnetic field to review mechanics, foster approximate reasoning and lateral class discussion, and demonstrate the…

  1. Testing a GaAs cathode in SRF gun

    SciTech Connect

    Wang, E.; Kewisch, J.; Ben-Zvi, I.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

    2011-03-28

    RF electron guns with a strained superlattice GaAs cathode are expected to generate polarized electron beams of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface and lower cathode temperature. We plan to install a bulk GaAs:Cs in a SRF gun to evaluate the performance of both the gun and the cathode in this environment. The status of this project is: In our 1.3 GHz 1/2 cell SRF gun, the vacuum can be maintained at nearly 10{sup -12} Torr because of cryo-pumping at 2K. With conventional activation of bulk GaAs, we obtained a QE of 10% at 532 nm, with lifetime of more than 3 days in the preparation chamber and have shown that it can survive in transport from the preparation chamber to the gun. The beam line has been assembled and we are exploring the best conditions for baking the cathode under vacuum. We report here the progress of our test of the GaAs cathode in the SRF gun. Future particle accelerators, such as eRHIC and the ILC require high-brightness, high-current polarized electrons. Strained superlattice GaAs:Cs has been shown to be an efficient cathode for producing polarized electrons. Activation of GaAs with Cs,O(F) lowers the electron affinity and makes it energetically possible for all the electrons, excited into the conduction band that drift or diffuse to the emission surface, to escape into the vacuum. Presently, all operating polarized electron sources, such as the CEBAF, are DC guns. In these devices, the excellent ultra-high vacuum extends the lifetime of the cathode. However, the low field gradient on the photocathode's emission surface of the DC guns limits the beam quality. The higher accelerating gradients, possible in the RF guns, generate a far better beam. Until recently, most RF guns operated at room temperature, limiting the vacuum to {approx}10{sup -9} Torr. This destroys the GaAs's NEA surface. The SRF guns combine the excellent vacuum conditions of DC guns and the high

  2. Nonpoint sources of volatile organic compounds in urban areas - Relative importance of land surfaces and air

    USGS Publications Warehouse

    Lopes, T.J.; Bender, D.A.

    1998-01-01

    Volatile organic compounds (VOCs) commonly detected in urban waters across the United States include gasoline-related compounds (e.g. toluene, xylene) and chlorinated compounds (e.g. chloroform, tetrachloroethane [PCE], trichloroethene [TCE]). Statistical analysis of observational data and results of modeling the partitioning of VOCs between air and water suggest that urban land surfaces are the primary nonpoint source of most VOCs. Urban air is a secondary nonpoint source, but could be an important source of the gasoline oxygenate methyl-tert butyl ether (MTBE). Surface waters in urban areas would most effectively be protected by controlling land-surface sources.

  3. A technique for the local measurement of air kerma rate from small Caesium-137 sources.

    PubMed

    Aukett, R J

    1991-10-01

    A method is described in which a Farmer ionization chamber is used for the direct measurement of the air kerma rate in air from small spherical Caesium-137 sources at distances of 35 to 70 mm. The calibration factor and corrections for source and ion chamber geometry are examined. For quality assurance purposes, the results obtained are in sufficient agreement with other methods of calibration.

  4. Evaluation of environmental impact of air pollution sources

    SciTech Connect

    Holnicki, P.

    2004-10-15

    This paper addresses the problem of evaluation and comparison of environmental impact of emission sources in the case of a complex, multisource emission field. The analysis is based on the forecasts of a short-term, dynamic dispersion model. The aim is to get a quantitative evaluation of the contribution of the selected sources according to the predefined, environmental cost function. The approach utilizes the optimal control technique for distributed parameter systems. The adjoint equation, related to the main transport equation of the forecasting model, is applied to calculate the sensitivity of the cost function to the emission intensity of the specified sources. An example implementation of a regional-scale, multilayer dynamic model of SOx transport is discussed as the main forecasting tool. The test computations have been performed for a set of the major power plants in a selected industrial region of Poland.

  5. Air spark-like plasma source for antimicrobial NOx generation

    NASA Astrophysics Data System (ADS)

    Pavlovich, M. J.; Ono, T.; Galleher, C.; Curtis, B.; Clark, D. S.; Machala, Z.; Graves, D. B.

    2014-12-01

    We demonstrate and analyse the generation of nitrogen oxides and their antimicrobial efficacy using atmospheric air spark-like plasmas. Spark-like discharges in air in a 1 L confined volume are shown to generate NOx at an initial rate of about 1.5  ×  1016 NOx molecules/J dissipated in the plasma. Such a discharge operating in this confined volume generates on the order of 6000 ppm NOx in 10 min. Around 90% of the NOx is in the form of NO2 after several minutes of operation in the confined volume, suggesting that NO2 is the dominant antimicrobial component. The strong antimicrobial action of the NOx mixture after several minutes of plasma operation is demonstrated by measuring rates of E. coli disinfection on surfaces and in water exposed to the NOx mixture. Some possible applications of plasma generation of NOx (perhaps followed by dissolution in water) include disinfection of surfaces, skin or wound antisepsis, and sterilization of medical instruments at or near room temperature.

  6. CHARACTERIZATION OF INDOOR AND OUTDOOR AIR POLLUTION EXPOSURES AND SOURCES

    EPA Science Inventory

    Human exposures to indoor and outdoor pollutants vary depending on the sources and concentrations of pollutants as well as human behavioral factors that determine the extent of an individual's contact with indoor or outdoor pollutants. In general, the older populations spend more...

  7. Source levels of northern elephant seal vocalizations in-air

    NASA Astrophysics Data System (ADS)

    Insley, Stephen J.; Southall, Brandon L.

    2005-09-01

    Accurate measurements of vocalization sound-pressure levels are necessary to determine the acoustical active space of animals in natural and human-altered ambient noise conditions. Despite this basic need, such data are limited or nonexistent for most species. Our study characterized aerial ambient noise and vocalization source levels for northern elephant seals during the breeding season. Subjects were adult males, lactating females, and dependent offspring (pups) at An~o Nuevo State Reserve. Source level measurements were made using a Type 1 sound level meter and calibrated microphones on-axis: (1) at 1 m; (2) at several known distances (laser measured); and (3) simultaneously at 1 m and a second known distance. Concurrent ambient noise conditions were measured in situ (non-weighted 5 min Leq integrated averages) and recorded for later spectral analysis. Measurements were made at two sites, one relatively noisy and the other relatively quiet, to determine whether animals compensate for higher noise conditions by increasing source levels (Lombard effect). Results indicate a wide range in signal strength, particularly for adult males whose vocalization source levels appear to be correlated with dominance rank and related to ambient noise conditions. The Lombard effect was not observed for adult females or elephant seal pups.

  8. Note: Characteristic beam parameter for the line electron gun.

    PubMed

    Iqbal, M; Islam, G U; Zhou, Z; Chi, Y

    2013-11-01

    We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm(2) at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm(2)), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful. PMID:24289448

  9. Note: Characteristic beam parameter for the line electron gun

    SciTech Connect

    Iqbal, M.; Islam, G. U.; Zhou, Z.; Chi, Y.

    2013-11-15

    We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm{sup 2} at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm{sup 2}), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

  10. Note: Characteristic beam parameter for the line electron gun.

    PubMed

    Iqbal, M; Islam, G U; Zhou, Z; Chi, Y

    2013-11-01

    We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm(2) at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm(2)), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

  11. Note: Characteristic beam parameter for the line electron gun

    NASA Astrophysics Data System (ADS)

    Iqbal, M.; Islam, G. U.; Zhou, Z.; Chi, Y.

    2013-11-01

    We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm2 at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm2), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

  12. Assessment of 2012 on-road mobile source episode specific emissions on air quality in Houston

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Shen, X.; Sarker, S.; Du, H.; Huque, Z.; Kommalapati, R. R.

    2015-12-01

    Houston has long been known to suffer from poor air quality, especially ground ozone level produced from photochemical reactions between nitrogen oxides (NOx) and Volatile Organic Compounds (VOC) in the presence of sunlight. In order to investigate impact of various emissions on air quality in Houston, combination of biogenic emissions with anthropogenic emissions were simulated for 2012 ozone episode. In this research, impact of on-road mobile source emissions on air quality in Houston were assessed. On-road mobile source inventories were developed using the EPA's MOVES (MOtor Vehicle Emission Simulator) model. Emissions Preprocessor System was used to convert the developed on-road mobile source inventories to suitable format. The converted on-road mobile source inventories were combined with biogenic emissions as the air quality model input. CAMx (Comprehensive Air quality Model with extensions) model was used to simulate various air pollutants concentrations for 2012 ozone episode. Simulation results showed that various transportation patterns have quite different influences on the air quality in this region.

  13. Locating and estimating air emissions from sources of arsenic and arsenic compounds. Final report

    SciTech Connect

    1998-06-01

    This document describes the properties of arsenic and arsenic compounds as air pollutants, defines production and use patterns, identifies source categories of air emissions, and provides emission factors. Arsenic is emitted as an air pollutant from external combustion boilers, municipal and hazardous waste incineration, primary copper and zinc smelting, glass manufacturing, copper ore mining, and primary and secondary lead smelting. Emissions of arsenic from these activities are due to the presence of trace amounts of arsenic in fuels and materials being processed. In such cases, the emissions may be quite variable because the trace presence of arsenic is not constant. Arsenic emissions also occur from agricultural chemical production and application, and also from metal processing due to the use of arsenic in these activities. In addition to the arsenic source information, information is provided that specifies how individual sources of arsenic may be tested to quantify air emissions.

  14. The polarized SRF gun experiment.

    SciTech Connect

    Kewisch,J.; Ben-Zvi, I.; Rao, T.; Burrill, A.; Pate, D.; Grover, R.; Todd, R.; Bluem, H.; Holmes, D.; Schultheiss, T.

    2007-09-10

    RF electron guns are capable of producing electron bunches with high brightness, which outperform DC electron guns and may even be able to provide electron beams for the ILC without the need for a damping ring. However, all successful existing guns for polarized electrons are DC guns because the environment inside an RF gun is hostile to the GaAs cathode material necessary for polarization. While the typical vacuum pressure in a DC gun is better than 10{sup -11} torr the vacuum in an RF gun is in the order of 10{sup -9} torr. Experiments at BINP Novosibirsk show that this leads to strong ion back-bombardment and generation of dark currents, which destroy the GaAs cathode in a short time. The situation might be much more favorable in a (super-conducting) SRF gun. The cryogenic pumping of the gun cavity walls may make it possible to maintain a vacuum close to 10{sup -12} torr, solving the problem of ion bombardment and dark currents. Of concern would be contamination of the gun cavity by evaporating cathode material. This report describes an experiment that Brookhaven National Laboratory (BNL) in collaboration with Advanced Energy Systems (AES) is conducting to answer these questions.

  15. SOLUTIONS TO INDOOR AIR PROBLEMS-LET'S FIRST UNDERSTAND THE SOURCE

    EPA Science Inventory

    The paper shows how EPA's Source Ranking Database (SRD) can be used, together with literature studies, to identify industrial product categories worthy of indoor air source characterization research. The SRD is a tool under development by EPA to identify potentially hazardous in...

  16. 78 FR 25242 - Delegation of New Source Performance Standards and National Emission Standards for Hazardous Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-30

    ... AGENCY 40 CFR Parts 60 and 61 Delegation of New Source Performance Standards and National Emission... Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAP... identity or contact information unless you provide it in the body of your comment. If you send...

  17. Toward a terahertz-driven electron gun.

    PubMed

    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

  18. Toward a terahertz-driven electron gun.

    PubMed

    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

    2015-10-21

    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.

  19. 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

  20. An Algorithm for Source Checking Continuous Air Monitors Using Radon Progeny

    SciTech Connect

    Hogue, M.G.

    2000-03-06

    Department of Energy requirements contained within 10CFR835 require that continuous air monitors be periodically checked for operability. The DOE air monitoring implementation guide for 10CFR835 allows the use of radon progeny to perform the recommended weekly source check. The Defense Waste Processing Facility located at the Savannah River Site has demonstrated that, through the use of the Hypotheses Concerning Two Means, diurnal changes in the radon progeny detected by the monitors meets the requirements for weekly source checks. The use of the diurnal changes in radon progeny has replaced the man-hours expended performing direct weekly source checking with an automated system requiring minimal man-hour expenditure.

  1. 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)

  2. Near-source air quality impacts of large olefin flares.

    PubMed

    Olaguer, Eduardo P

    2012-08-01

    Large petrochemicalflares, common in the Houston Ship Channel (the Ship Channel) and other industrialized areas in the Gulfof Mexico region, emit hundreds to thousands of pounds per hour of highly reactive volatile organic compounds (HRVOCs). We employedfine horizontal resolution (200 mx200 m) in a three-dimensional (3D) Eulerian chemical transport model to simulate two historical Ship Channel flares. The model reasonably reproduced the observed ozone rise at the nearest monitoring stations downwind of the flares. The larger of the two flares had an olefin emission rate exceeding 1400 lb/hr. In this case, the model simulated a rate of increase in peak ozone greater than 40 ppb/hr over a 12 kmx12 km horizontal domain without any unusual meteorological conditions. In this larger flare, formaldehyde emissions typically neglected in official inventories enhanced peak ozone by as much as 16 ppb and contributed over 10 ppb to ambient formaldehyde up to approximately 8 km downwind of the flare. The intense horizontal gradients in large flare plumes cannot be simulated by coarse models typically used to demonstrate ozone attainment. Moreover even the relatively dense monitoring network in the Ship Channel may not be able to detect many transient high ozone events (THOEs) caused by industrial flare emissions in the absence of stagnant air recirculation or stalled sea breeze fronts, even though such conditions are unnecessary for the occurrence of THOEs.

  3. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  4. Source apportionment of polycyclic aromatic hydrocarbons and their derivatives in indoor air

    SciTech Connect

    Ray, B.; Mitra, S.

    1996-12-31

    The average person spends more than 80% of his time indoors, thus analysis of the sources of airborne pollutants in indoor air is an important issue. In this paper, we use factor analysis and multiple regression to identify and apportion the different sources of select indoor polycyclic aromatic hydrocarbons (PAHs), their derivatives, and nicotine in indoor air, using data gathered in eight homes in Columbus, OH during the winter of 1986/1987. These homes had different indoor PAH sources, namely, environmental tobacco smoke, gas cooking/heating, and electrical cooking stoves. We find that, of all the sources, environmental tobacco smoke appears to have the greatest impact on the total indoor PAH concentrations. In smokers` homes, more than 87% of the total PAH is due to this source. Background sources are the largest contributor to PAHs in nonsmokers` homes. Very little PAH can be attributed to gas or electric appliances in the home. 16 refs., 3 tabs.

  5. Magnetron injection gun scaling

    NASA Astrophysics Data System (ADS)

    Lawson, W.

    1988-04-01

    A set of tradeoff equations was simplified to obtain scaling laws for magnetron injection guns (MIGs). The constraints are chosen to examine the maximum-peak-power capabilities of MIGs. The scaling laws are compared with exact solutions of the design equations and are supported by MIG simulations in which each MIG is designed to double the beam power of an existing design by adjusting one of the four fundamental parameters.

  6. 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.

  7. Methods, fluxes and sources of gas phase alkyl nitrates in the coastal air.

    PubMed

    Dirtu, Alin C; Buczyńska, Anna J; Godoi, Ana F L; Favoreto, Rodrigo; Bencs, László; Potgieter-Vermaak, Sanja S; Godoi, Ricardo H M; Van Grieken, René; Van Vaeck, Luc

    2014-10-01

    The daily and seasonal atmospheric concentrations, deposition fluxes and emission sources of a few C3-C9 gaseous alkyl nitrates (ANs) at the Belgian coast (De Haan) on the Southern North Sea were determined. An adapted sampler design for low- and high-volume air-sampling, optimized sample extraction and clean-up, as well as identification and quantification of ANs in air samples by means of gas chromatography mass spectrometry, are reported. The total concentrations of ANs ranged from 0.03 to 85 pptv and consisted primarily of the nitro-butane and nitro-pentane isomers. Air mass backward trajectories were calculated by the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to determine the influence of main air masses on AN levels in the air. The shorter chain ANs have been the most abundant in the Atlantic/Channel/UK air masses, while longer chain ANs prevailed in continental air. The overall mean N fluxes of the ANs were slightly higher for summer than those for winter-spring, although their contributions to the total nitrogen flux were low. High correlations between AN and HNO₂ levels were observed during winter/spring. During summer, the shorter chain ANs correlated well with precipitation. Source apportionment by means of principal component analysis indicated that most of the gas phase ANs could be attributed to traffic/combustion, secondary photochemical formation and biomass burning, although marine sources may also have been present and a contributing factor. PMID:24952420

  8. Methods, fluxes and sources of gas phase alkyl nitrates in the coastal air.

    PubMed

    Dirtu, Alin C; Buczyńska, Anna J; Godoi, Ana F L; Favoreto, Rodrigo; Bencs, László; Potgieter-Vermaak, Sanja S; Godoi, Ricardo H M; Van Grieken, René; Van Vaeck, Luc

    2014-10-01

    The daily and seasonal atmospheric concentrations, deposition fluxes and emission sources of a few C3-C9 gaseous alkyl nitrates (ANs) at the Belgian coast (De Haan) on the Southern North Sea were determined. An adapted sampler design for low- and high-volume air-sampling, optimized sample extraction and clean-up, as well as identification and quantification of ANs in air samples by means of gas chromatography mass spectrometry, are reported. The total concentrations of ANs ranged from 0.03 to 85 pptv and consisted primarily of the nitro-butane and nitro-pentane isomers. Air mass backward trajectories were calculated by the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to determine the influence of main air masses on AN levels in the air. The shorter chain ANs have been the most abundant in the Atlantic/Channel/UK air masses, while longer chain ANs prevailed in continental air. The overall mean N fluxes of the ANs were slightly higher for summer than those for winter-spring, although their contributions to the total nitrogen flux were low. High correlations between AN and HNO₂ levels were observed during winter/spring. During summer, the shorter chain ANs correlated well with precipitation. Source apportionment by means of principal component analysis indicated that most of the gas phase ANs could be attributed to traffic/combustion, secondary photochemical formation and biomass burning, although marine sources may also have been present and a contributing factor.

  9. Methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

    DOEpatents

    Moore, Karen A.; Zatorski, Raymond A.

    2007-10-02

    Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

  10. Systems and methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

    DOEpatents

    Moore, Karen A.; Zatorski, Raymond A.

    2005-07-12

    Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

  11. Improved DC Gun Insulator Assembly

    SciTech Connect

    Sah, R.; Dudas, A.; Neubauer, M. L.; Poelker, M.; Surles-Law, K. E.L.

    2010-05-23

    Many user fa­cil­i­ties such as syn­chrotron ra­di­a­tion light sources and free elec­tron lasers re­quire ac­cel­er­at­ing struc­tures that sup­port elec­tric fields of 10-100 MV/m, es­pe­cial­ly at the start of the ac­cel­er­a­tor chain where ce­ram­ic in­su­la­tors are used for very high gra­di­ent DC guns. These in­su­la­tors are dif­fi­cult to man­u­fac­ture, re­quire long com­mis­sion­ing times, and often ex­hib­it poor re­li­a­bil­i­ty. Two tech­ni­cal ap­proach­es to solv­ing this prob­lem will be in­ves­ti­gat­ed. First­ly, in­vert­ed ce­ram­ics offer so­lu­tions for re­duced gra­di­ents be­tween the elec­trodes and ground. An in­vert­ed de­sign will be pre­sent­ed for 350 kV, with max­i­mum gra­di­ents in the range of 5-10 MV/m. Sec­ond­ly, novel ce­ram­ic man­u­fac­tur­ing pro­cess­es will be stud­ied, in order to pro­tect triple junc­tion lo­ca­tions from emis­sion, by ap­ply­ing a coat­ing with a bulk re­sis­tiv­i­ty. The pro­cess­es for cre­at­ing this coat­ing will be op­ti­mized to pro­vide pro­tec­tion as well as be used to coat a ce­ram­ic with an ap­pro­pri­ate gra­di­ent in bulk re­sis­tiv­i­ty from the vac­u­um side to the air side of an HV stand­off ce­ram­ic cylin­der. Ex­am­ple in­su­la­tor de­signs are being com­put­er mod­elled, and in­su­la­tor sam­ples are being man­u­fac­tured and test­ed

  12. A large volume 2000 MPA air source for the radiatively driven hypersonic wind tunnel

    SciTech Connect

    Constantino, M

    1999-07-14

    An ultra-high pressure air source for a hypersonic wind tunnel for fluid dynamics and combustion physics and chemistry research and development must provide a 10 kg/s pure air flow for more than 1 s at a specific enthalpy of more than 3000 kJ/kg. The nominal operating pressure and temperature condition for the air source is 2000 MPa and 900 K. A radial array of variable radial support intensifiers connected to an axial manifold provides an arbitrarily large total high pressure volume. This configuration also provides solutions to cross bore stress concentrations and the decrease in material strength with temperature. [hypersonic, high pressure, air, wind tunnel, ground testing

  13. Ultraviolet-B radiation enhancement in dielectric barrier discharge based xenon chloride exciplex source by air

    SciTech Connect

    Gulati, P.; Prakash, R.; Pal, U. N.; Kumar, M.; Vyas, V.

    2014-07-07

    A single barrier dielectric barrier discharge tube of quartz with multi-strip Titanium-Gold (Ti-Au) coatings have been developed and utilized for ultraviolet-B (UV-B) radiation production peaking at wavelength 308 nm. The observed radiation at this wavelength has been examined for the mixtures of the Xenon together with chlorine and air admixtures. The gas mixture composition, chlorine gas content, total gas pressure, and air pressure dependency of the UV intensity, has been analyzed. It is found that the larger concentration of Cl{sub 2} deteriorates the performance of the developed source and around 2% Cl{sub 2} in this source produced optimum results. Furthermore, an addition of air in the xenon and chlorine working gas environment leads to achieve same intensity of UV-B light but at lower working gas pressure where significant amount of gas is air.

  14. Development of S-band photocathode RF guns at Tsinghua University

    NASA Astrophysics Data System (ADS)

    Zheng, Lianmin; Du, Yingchao; Zhang, Zhe; Qian, Houjun; Yan, Lixin; Shi, Jiaru; Zhang, Zhen; Zhou, Zheng; Wu, Xiaowei; Su, Xiaolu; Wang, Dong; Tian, Qili; Huang, Wenhui; Chen, Huaibi; Tang, Chuanxiang

    2016-10-01

    This study aims to explain the development of S-band photocathode RF guns at Tsinghua University, with especial attention on the progress of guns developed after 2011. Two types of RF guns were developed based on the BNL/SLAC/UCLA gun prior 2011. These guns have been operated as electron sources for Tsinghua Thomson scattering X-ray source (TTX), MeV ultrafast electron diffraction, and Shanghai deep ultraviolet FEL test facility. Based on our operation experiences and other gun modifications worldwide, numerous improvements have been proposed, and seven third-type guns have been designed and fabricated since 2011. Cold tests of all third-type guns have been completed, confirming a significantly improved quality factor and mode separation. The first third-type gun has been installed on TTX and operated for four years, demonstrating high gradient, low dark current, stable quantum efficiency, and small emittances. The optimal transverse emittance was εx = 0.56 mm mrad , εy = 0.66 mm mrad for 200 pC with a peak current of 25 A, and εx = 0.78 mm mrad , εy = 0.92 mm mrad for 500 pC with a peak current of 62.5 A under a 110 MV/m gun gradient.

  15. New National Air-Kerma Standard for Low-Energy Electronic Brachytherapy Sources

    PubMed Central

    Seltzer, Stephen M; O’Brien, Michelle; Mitch, Michael G

    2014-01-01

    The new primary standard for low-energy electronic brachytherapy sources for the United States is described. These miniature x-ray tubes are inserted in catheters for interstitial radiation therapy and operate at tube potentials of up to about 50 kV. The standard is based on the realization of the air kerma produced by the x-ray beam at a reference distance in air of 50 cm. PMID:26601044

  16. Oxidative potential and inflammatory impacts of source apportioned ambient air pollution in Beijing.

    PubMed

    Liu, Qingyang; Baumgartner, Jill; Zhang, Yuanxun; Liu, Yanju; Sun, Yongjun; Zhang, Meigen

    2014-11-01

    Air pollution exposure is associated with a range of adverse health impacts. Knowledge of the chemical components and sources of air pollution most responsible for these health effects could lead to an improved understanding of the mechanisms of such effects and more targeted risk reduction strategies. We measured daily ambient fine particulate matter (<2.5 μm in aerodynamic diameter; PM2.5) for 2 months in peri-urban and central Beijing, and assessed the contribution of its chemical components to the oxidative potential of ambient air pollution using the dithiothreitol (DTT) assay. The composition data were applied to a multivariate source apportionment model to determine the PM contributions of six sources or factors: a zinc factor, an aluminum factor, a lead point factor, a secondary source (e.g., SO4(2-), NO3(2-)), an iron source, and a soil dust source. Finally, we assessed the relationship between reactive oxygen species (ROS) activity-related PM sources and inflammatory responses in human bronchial epithelial cells. In peri-urban Beijing, the soil dust source accounted for the largest fraction (47%) of measured ROS variability. In central Beijing, a secondary source explained the greatest fraction (29%) of measured ROS variability. The ROS activities of PM collected in central Beijing were exponentially associated with in vivo inflammatory responses in epithelial cells (R2=0.65-0.89). We also observed a high correlation between three ROS-related PM sources (a lead point factor, a zinc factor, and a secondary source) and expression of an inflammatory marker (r=0.45-0.80). Our results suggest large differences in the contribution of different PM sources to ROS variability at the central versus peri-urban study sites in Beijing and that secondary sources may play an important role in PM2.5-related oxidative potential and inflammatory health impacts.

  17. Levels, sources, and health risks of carbonyls in residential indoor air in Hangzhou, China.

    PubMed

    Weng, Mili; Zhu, Lizhong; Yang, Kun; Chen, Shuguang

    2010-04-01

    Concentrations of formaldehyde, acetaldehyde, acetone, propionaldehyde, i-pentanal, and butyraldehyde in residential indoor air in Hangzhou were determined. The mean concentration of the total carbonyl compounds in summer was 222.6 microg/m(3), higher than that in winter (68.5 microg/m(3)). The concentration of a specific carbonyl in indoor air was higher than the outdoor air measurement, indicating the release of carbonyls from the indoor sources. Formaldehyde and acetone were the most abundant carbonyls detected in summer and winter, respectively. Multiple regression analysis indicated that carbonyl concentrations in residential indoor air depended on the age of decoration and furniture, as well as their concentrations in outdoor air. In addition, a primary estimation showed that the health risks of carbonyls in summer were higher than those in winter.

  18. Modeling indoor air concentrations near emission sources in imperfectly mixed rooms.

    PubMed

    Furtaw, E J; Pandian, M D; Nelson, D R; Behar, J V

    1996-09-01

    Assessments of exposure to indoor air pollutants usually employ spatially well-mixed models which assume homogeneous concentrations throughout a building or room. However, practical experience and experimental data indicate that concentrations are not uniform in rooms containing point sources of emissions; concentrations tend to be greater in close proximity to the source than they are further from it. This phenomenon could account for the observation that "personal air" monitors frequently yield higher concentrations than nearby microenvironmental monitors (i.e., the so-called "personal cloud" effect). In this project, we systematically studied the concentrations of a tracer gas at various distances from its emission source in a controlled-environment, room-size chamber under a variety of ventilation conditions. Measured concentrations in the proximity of the source deviated significantly above the predictions of a conventional well-mixed single-compartment mass balance model. The deviation was found to be a function of distance from the source and total room air flow rate. At typical air flow rates, the average concentration at arm's length (approximately 0.4 meters) from the source exceeds the theoretical well-mixed concentration by a ratio of about 2:1. However, this ratio is not constant; the monitored concentration appears to vary randomly from near the theoretical value to several times above it. Concentration data were fitted to a two-compartment model with the source located in a small virtual compartment within the room compartment. These two compartments were linked with a stochastic air transfer rate parameter. The resulting model provides a more realistic simulation of exposure concentrations than does the well-mixed model for assessing exposure to emissions from active sources. Parameter values are presented for using the enhanced model in a variety of typical situations. PMID:8925388

  19. Final Technical Report- Back-gate Field Emission-based Cathode RF Electron Gun

    SciTech Connect

    McGuire, Gary; Martin, Allen; Noonan, John

    2010-10-30

    The objective was to complete the design of an electron gun which utilizes a radio frequency (RF) power source to apply a voltage to a field emission (FE) cathode, a so called cold cathode, in order to produce an electron beam. The concept of the RF electron gun was originally conceived at Argonne National Laboratory but never reduced to practice. The research allowed the completion of the design based upon the integration of the FE electron source. Compared to other electron guns, the RF gun is very compact, less than one third the size of other comparable guns, and produces a high energy (to several MeV), high quality, high power electron beam with a long focal length with high repetition rates. The resultant electron gun may be used in welding, materials processing, analytical equipment and waste treatment.

  20. Air toxics concentrations, source identification, and health risks: An air pollution hot spot in southwest Memphis, TN

    NASA Astrophysics Data System (ADS)

    Jia, Chunrong; Foran, Jeffery

    2013-12-01

    Southwest Memphis is a residential region surrounded by fossil fuel burning, steel, refining, and food processing industries, and considerable mobile sources whose emissions may pose adverse health risks to local residents. This study characterizes cancer and non-cancer risks resulting from exposure to ambient air toxics in southwest Memphis. Air toxics samples were collected at a central location every 6 days from June 5, 2008 to January 8, 2010. Volatile organic compounds (VOCs) were collected in evacuated stainless-steel canisters and aldehydes by DNPH cartridges, and samples were analyzed for 73 target compounds. A total of 60 compounds were detected and 39 were found in over 86% of the samples. Mean concentrations of many compounds were higher than those measured in many industrial communities throughout the U.S. The cumulative cancer risk associated with exposure to 13 carcinogens found in southwest Memphis air was 2.3 × 10-4, four times higher than the national average of 5.0 × 10-5. Three risk drivers were identified: benzene, formaldehyde, and acrylonitrile, which contributed 43%, 19%, and 14% to the cumulative risk, respectively. This is the first field study to confirm acrylonitrile as a potential risk driver. Mobile, secondary, industrial, and background sources contributed 57%, 24%, 14%, and 5% of the risk, respectively. The results of this study indicate that southwest Memphis, a region of significant income, racial, and social disparities, is also a region under significant environmental stress compared with surrounding areas and communities.

  1. Air pollutant emission rates for sources at the Deaf Smith County repository site

    SciTech Connect

    Not Available

    1985-11-01

    This document summarizes the air-quality source terms used for the Deaf Smith County, Texas environmental assessment report and explains their derivation. The engineering data supporting these source terms appear as appendixes to this report and include summary equipment lists for the repository and detailed equipment lists for the exploratory shaft. Although substantial work has been performed in establishing the current repository design, a greater effort will be required for the final design. Consequently, the repository emission rates presented here should be considered as preliminary estimates. Another set of air pollution emission rates will be calculated after design data are more firmly established. 18 refs., 15 tabs.

  2. Dependence with air density of the response of the PTW SourceCheck ionization chamber for low energy brachytherapy sources

    SciTech Connect

    Tornero-López, Ana M.; Guirado, Damián; Ruiz-Arrebola, Samuel; Perez-Calatayud, Jose; Simancas, Fernando; Lallena, Antonio M.; Gazdic-Santic, Maja

    2013-12-15

    Purpose: Air-communicating well ionization chambers are commonly used to assess air kerma strength of sources used in brachytherapy. The signal produced is supposed to be proportional to the air density within the chamber and, therefore, a density-independent air kerma strength is obtained when the measurement is corrected to standard atmospheric conditions using the usual temperature and pressure correction factor. Nevertheless, when assessing low energy sources, the ionization chambers may not fulfill that condition and a residual density dependence still remains after correction. In this work, the authors examined the behavior of the PTW 34051 SourceCheck ionization chamber when measuring the air kerma strength of {sup 125}I seeds.Methods: Four different SourceCheck chambers were analyzed. With each one of them, two series of measurements of the air kerma strength for {sup 125}I selectSeed{sup TM} brachytherapy sources were performed inside a pressure chamber and varying the pressure in a range from 747 to 1040 hPa (560 to 780 mm Hg). The temperature and relative humidity were kept basically constant. An analogous experiment was performed by taking measurements at different altitudes above sea level.Results: Contrary to other well-known ionization chambers, like the HDR1000 PLUS, in which the temperature-pressure correction factor overcorrects the measurements, in the SourceCheck ionization chamber they are undercorrected. At a typical atmospheric situation of 933 hPa (700 mm Hg) and 20 °C, this undercorrection turns out to be 1.5%. Corrected measurements show a residual linear dependence on the density and, as a consequence, an additional density dependent correction must be applied. The slope of this residual linear density dependence is different for each SourceCheck chamber investigated. The results obtained by taking measurements at different altitudes are compatible with those obtained with the pressure chamber.Conclusions: Variations of the altitude and

  3. EXPOSURE VERSION 2 - A COMPUTER MODEL FOR ANALYZING THE EFFECTS OF INDOOR AIR POLLUTANT SOURCES ON INDIVIDUAL EXPOSURE

    EPA Science Inventory

    The report presents a model for calculating individual exposure to indoor pollutants from sources. The model calculates exposure due to individual, as opposed to population, activity patterns and source use. The model uses data on source emissions, room- to- room air flows, air e...

  4. Gun Concerns Personal for Duncan

    ERIC Educational Resources Information Center

    McNeil, Michele

    2013-01-01

    As U.S. Secretary of Education Arne Duncan works with other Obama administration officials on policy responses to the shootings at a Connecticut elementary school, he brings a personal and professional history that has acquainted him with the impact of gun violence. As schools chief in Chicago from 2001 to 2008, he was affected by the gun deaths…

  5. Pattern recognition methods and air pollution source identification. [based on wind direction

    NASA Technical Reports Server (NTRS)

    Leibecki, H. F.; King, R. B.

    1978-01-01

    Directional air samplers, used for resolving suspended particulate matter on the basis of time and wind direction were used to assess the feasibility of characterizing and identifying emission source types in urban multisource environments. Filters were evaluated for 16 elements and X-ray fluorescence methods yielded elemental concentrations for direction, day, and the interaction of direction and day. Large numbers of samples are necessary to compensate for large day-to-day variations caused by wind perturbations and/or source changes.

  6. Source apportionment of airborne particulate matter in Southeast Texas using a source-oriented 3D air quality model

    NASA Astrophysics Data System (ADS)

    Zhang, Hongliang; Ying, Qi

    2010-09-01

    A nested version of the source-oriented externally mixed UCD/CIT model was developed to study the source contributions to airborne particulate matter (PM) during a two-week long air quality episode during the Texas 2000 Air Quality Study (TexAQS 2000). Contributions to primary PM and secondary ammonium sulfate in the Houston-Galveston Bay (HGB) and Beaumont-Port Arthur (BPA) areas were determined. The predicted 24-h elemental carbon (EC), organic compounds (OC), sulfate, ammonium ion and primary PM 2.5 mass are in good agreement with filter-based observations. Predicted concentrations of hourly sulfate, ammonium ion, and primary OC from diesel and gasoline engines and biomass burning organic aerosol (BBOA) at La Porte, Texas agree well with measurements from an Aerodyne Aerosol Mass Spectrometer (AMS). The UCD/CIT model predicts that EC is mainly from diesel engines and majority of the primary OC is from internal combustion engines and industrial sources. Open burning contributes large fractions of EC, OC and primary PM 2.5 mass. Road dust, internal combustion engines and industries are the major sources of primary PM 2.5. Wildfire dominates the contributions to all primary PM components in areas near the fires. The predicted source contributions to primary PM are in general agreement with results from a chemical mass balance (CMB) model. Discrepancy between the two models suggests that further investigations on the industrial PM emissions are necessary. Secondary ammonium sulfate accounts for the majority of the secondary inorganic PM. Over 80% of the secondary sulfate in the 4 km domain is produced in upwind areas. Coal combustion is the largest source of sulfate. Ammonium ion is mainly from agriculture sources and contributions from gasoline vehicles are significant in urban areas.

  7. Preventing gun injuries in children.

    PubMed

    Crossen, Eric J; Lewis, Brenna; Hoffman, Benjamin D

    2015-02-01

    Firearms are involved in the injury and death of a large number of children each year from both intentional and unintentional causes. Gun ownership in homes with children is common, and pediatricians should incorporate evidence-based means to discuss firearms and protect children from gun-related injuries and violence. Safe storage of guns, including unloaded guns locked and stored separately from ammunition, can decrease risks to children, and effective tools are available that pediatricians can use in clinical settings to help decrease children's access to firearms. Furthermore, several community-based interventions led by pediatricians have effectively reduced firearm-related injury risks to children. Educational programs that focus on children's behavior around guns have not proven effective.

  8. LCLS Gun Solenoid Design Considerations

    SciTech Connect

    Schmerge, John

    2010-12-10

    The LCLS photocathode rf gun requires a solenoid immediately downstream for proper emittance compensation. Such a gun and solenoid have been operational at the SSRL Gun Test Facility (GTF) for over eight years. Based on magnetic measurements and operational experience with the GTF gun solenoid multiple modifications are suggested for the LCLS gun solenoid. The modifications include adding dipole and quadrupole correctors inside the solenoid, increasing the bore to accommodate the correctors, decreasing the mirror plate thickness to allow the solenoid to move closer to the cathode, cutouts in the mirror plate to allow greater optical clearance with grazing incidence cathode illumination, utilizing pancake coil mirror images to compensate the first and second integrals of the transverse fields and incorporating a bipolar power supply to allow for proper magnet standardization and quick polarity changes. This paper describes all these modifications plus the magnetic measurements and operational experience leading to the suggested modifications.

  9. A Guide to Instruction in the Shooting Sports-Rifles; Air Rifles; Shotguns; Pistols; Hunter Safety.

    ERIC Educational Resources Information Center

    Niemeyer, Roy K.; And Others

    Prepared for instruction in the use of rifles, air guns, shotguns, pistols, and hunter safety, this guide supplements other materials which are available from the National Rifle Association of America, the National Shooting Sports Foundation, the American Association for Health, Physical Education, and Recreation, industry, and other sources. The…

  10. Electric arc welding gun

    DOEpatents

    Luttrell, Edward; Turner, Paul W.

    1978-01-01

    This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.

  11. Development of PM2.5 source impact spatial fields using a hybrid source apportionment air quality model

    NASA Astrophysics Data System (ADS)

    Ivey, C. E.; Holmes, H. A.; Hu, Y. T.; Mulholland, J. A.; Russell, A. G.

    2015-01-01

    An integral part of air quality management is knowledge of the impact of pollutant sources on ambient concentrations of particulate matter (PM). There is also a growing desire to directly use source impact estimates in health studies; however, source impacts cannot be directly measured. Several limitations are inherent in most source apportionment methods, which has led to the development of a novel hybrid approach that is used to estimate source impacts by combining the capabilities of receptor modeling (RM) and chemical transport modeling (CTM). The hybrid CTM-RM method calculates adjustment factors to refine the CTM-estimated impact of sources at monitoring sites using pollutant species observations and the results of CTM sensitivity analyses, though it does not directly generate spatial source impact fields. The CTM used here is the Community Multi-Scale Air Quality (CMAQ) model, and the RM approach is based on the Chemical Mass Balance model. This work presents a method that utilizes kriging to spatially interpolate source-specific impact adjustment factors to generate revised CTM source impact fields from the CTM-RM method results, and is applied to January 2004 over the continental United States. The kriging step is evaluated using data withholding and by comparing results to data from alternative networks. Directly applied and spatially interpolated hybrid adjustment factors at withheld monitors had a correlation coefficient of 0.89, a linear regression slope of 0.83 ± 0.02, and an intercept of 0.14 ± 0.02. Refined source contributions reflect current knowledge of PM emissions (e.g., significant differences in biomass burning impact fields). Concentrations of 19 species and total PM2.5 mass were reconstructed for withheld monitors using directly applied and spatially interpolated hybrid adjustment factors. The mean concentrations of total PM2.5 for withheld monitors were 11.7 (± 8.3), 16.3 (± 11), 8.59 (± 4.7), and 9.20 (± 5.7) μg m-3 for the

  12. CANDLES AND INCENSE AS POTENTIAL SOURCES OF INDOOR AIR POLLUTION: MARKET ANALYSIS AND LITERATURE SEARCH

    EPA Science Inventory

    The report summarizes available information on candles and incense as potential sources of indoor air pollution. It covers market information and a review of the scientific literature. The market information collected focuses on production and sales data, typical uses in the U.S....

  13. Temporal and modal characterization of DoD source air toxic emission factors: final report

    EPA Science Inventory

    This project tested three, real-/near real-time monitoring techniques to develop air toxic emission factors for Department of Defense (DoD) platform sources. These techniques included: resonance enhanced multi photon ionization time of flight mass spectrometry (REMPI-TOFMS) for o...

  14. An Inexpensive Autosampler to Maximize Throughput for an Ion Source that Samples Surfaces in Open Air

    EPA Science Inventory

    An autosampler was built to pull cotton swab heads mounted into a 3-foot long, square Al rod in ambient air through the He ionizing beam of a Direct Analysis in Real Time (DART) ion source interfaced to an orthogonal acceleration, time-of-flight mass spectrometer. The cost of th...

  15. 76 FR 74708 - National Emission Standards for Hazardous Air Pollutants for Source Categories

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-01

    ... AGENCY 40 CFR Part 63 National Emission Standards for Hazardous Air Pollutants for Source Categories CFR Correction In Title 40 of the Code of Federal Regulations, Part 63 (Sec. Sec. 63.600 to 63.1199), revised as of July 1, 2011, on page 602, Sec. 63.1196 is reinstated to read as follows: Sec. 63.1196...

  16. Identification of secondary lead sources in the air of an urban environment

    NASA Astrophysics Data System (ADS)

    Chiaradia, Massimo; Gulson, Brian L.; James, Matthew; William Jameson, C.; Johnson, David

    High precision lead isotopic data have been measured from particulates deposited on filters from two suburbs of Sydney (NSW, Australia) and gasoline from two main brands to evaluate the source of lead in air following the phasing out of leaded gasoline in Sydney in 1986 and a 25% reduction of lead in leaded gasoline in 1994. These measures have resulted in a 75% reduction of lead in Sydney air nowadays. Despite these positive figures, our results indicate that gasoline still accounts for more than 90% of the lead in the atmosphere of this city. However, when compared with an earlier investigation carried out in the period 1979-1981, our data show that a background source with a 206Pb/ 204Ph isotopic ratio higher than petrol has become detectable. We have used a best fitting mathematical procedure to identify the isotopic ratio and percentage contribution of this source to the air. The values that we have obtained are ˜ 18.2 and ˜7%, respectively, for the 206Pb/204Pb ratio and the percentage contribution. Several local background sources are considered, including natural lead from soils, wood burning, coal burning in power stations and aircraft profellants. We also draw attention to the similarity of the background isotopic composition in Sydney air aid isotopic ratios measured in snows of Antarctica.

  17. Separating the Air Quality Impact of a Major Highway and Nearby Sources by Nonparametric Trajectory Analysis

    EPA Science Inventory

    Nonparametric Trajectory Analysis (NTA), a receptor-oriented model, was used to assess the impact of local sources of air pollution at monitoring sites located adjacent to highway I-15 in Las Vegas, NV. Measurements of black carbon, carbon monoxide, nitrogen oxides, and sulfur di...

  18. Investigating the Link Between Gun Possession and Gun Assault

    PubMed Central

    Richmond, Therese S.; Culhane, Dennis P.; Ten Have, Thomas R.; Wiebe, Douglas J.

    2009-01-01

    Objectives. We investigated the possible relationship between being shot in an assault and possession of a gun at the time. Methods. 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. Results. 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). Conclusions. 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. PMID:19762675

  19. Intake fraction variability between air pollution emission sources inside an urban area.

    PubMed

    Tainio, Marko; Holnicki, Piotr; Loh, Miranda M; Nahorski, Zbigniew

    2014-11-01

    The cost-effective mitigation of adverse health effects caused by air pollution requires information on the contribution of different emission sources to exposure. In urban areas the exposure potential of different sources may vary significantly depending on emission height, population density, and other factors. In this study, we quantified this intraurban variability by predicting intake fraction (iF) for 3,066 emission sources in Warsaw, Poland. iF describes the fraction of the pollutant that is inhaled by people in the study area. We considered the following seven pollutants: particulate matter (PM), nitrogen oxides (NOx), sulfur dioxide (SO2), benzo[a] pyrene (BaP), nickel (Ni), cadmium (Cd), and lead (Pb). Emissions for these pollutants were grouped into four emission source categories (Mobile, Area, High Point, and Other Point sources). The dispersion of the pollutants was predicted with the CALPUFF dispersion model using the year 2005 emission rate data and meteorological records. The resulting annual average concentrations were combined with population data to predict the contribution of each individual source to population exposure. The iFs for different pollutant-source category combinations varied between 51 per million (PM from Mobile sources) and 0.013 per million (sulfate PM from High Point sources). The intraurban iF variability for Mobile sources primary PM emission was from 4 per million to 100 per million with the emission-weighted iF of 44 per million. These results propose that exposure due to intraurban air pollution emissions could be decreased more effectively by specifically targeting sources with high exposure potency rather than all sources.

  20. Dynamic effects on containment of air-curtain fume hood operated with heat source.

    PubMed

    Chen, Jia-Kun; Huang, Rong Fung; Hsin, Pei-Yi

    2012-01-01

    This study focused on the leakage characteristics of the air-curtain fume hood that are subject to the influences of sash movement and walk-by motion while a high temperature heat source was operated in the hood. The flow visualization and trace gas test method were used to investigate the performance of the air-curtain fume hood. An electric heater was placed in the hood to simulate the heat source. The temperature of the heat source installed inside the air-curtain fume hood varied between 180°C and 300°C. Trace gas tests following the dynamic test methods of EN-14175 protocol were employed to measure the spillages of sulfur hexafluoride gas that were released in the hood. When subject to the influence of sash movement at a heat source temperature lower than 260°C, the leakage level was high at the suction velocity V(s) < 8 m/sec but was negligibly small at V(s) > 10 m/sec. When subject to the influence of people walk-by, the leakage level was relatively low at the suction velocity larger than 8 m/sec at sash height H = 50 cm. The height of the sash opening was a crucial parameter for the containment of the air-curtain fume hood. At the sash opening lower than about 25 cm, suction velocity less than or equal to 6 m/sec was enough to make the sulfur hexafluoride leakage less than the threshold value, 0.65 ppm, suggested by the BG Chemie. The air-curtain fume hood presented a great performance to resist the effect of drafts even though there was a high temperature heat source working in the hood. PMID:23009207

  1. 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.

  2. Background information on sources of low-level radionuclide emissions to air

    SciTech Connect

    Corbit, C.D.; Herrington, W.N.; Higby, D.P.; Stout, L.A.; Corley, J.P.

    1983-09-01

    This report provides a general description and reported emissions for eight low-level radioactive source categories, including facilties that are licensed by the Nuclear Regulatory Commission (NRC) and Agreement States, and non-Department of Energy (DOE) federal facilities. The eight categories of low-level radioactive source facilities covered by this report are: research and test reactors, accelerators, the radiopharmaceutical industry, source manufacturers, medical facilities, laboratories, naval shipyards, and low-level commercial waste disposal sites. Under each category five elements are addressed: a general description, a facility and process description, the emission control systems, a site description, and the radionuclides released to air (from routine operations).

  3. Sources of Indoor Air Pollution and Respiratory Health in Preschool Children

    PubMed Central

    Fuentes-Leonarte, Virginia; Ballester, Ferran; Tenías, José Maria

    2009-01-01

    We carried out bibliographic searches in PubMed and Embase.com for the period from 1996 to 2008 with the aim of reviewing the scientific literature on the relationship between various sources of indoor air pollution and the respiratory health of children under the age of five. Those studies that included adjusted correlation measurements for the most important confounding variables and which had an adequate population size were considered to be more relevant. The results concerning the relationship between gas energy sources and children's respiratory health were heterogeneous. Indoor air pollution from biomass combustion in the poorest countries was found to be an important risk factor for lower respiratory tract infections. Solvents involved in redecorating, DYI work, painting, and so forth, were found to be related to an increased risk for general respiratory problems. The distribution of papers depending on the pollution source showed a clear relationship with life-style and the level of development. PMID:20168984

  4. Sources of indoor air pollution and respiratory health in preschool children.

    PubMed

    Fuentes-Leonarte, Virginia; Ballester, Ferran; Tenías, José Maria

    2009-01-01

    We carried out bibliographic searches in PubMed and Embase.com for the period from 1996 to 2008 with the aim of reviewing the scientific literature on the relationship between various sources of indoor air pollution and the respiratory health of children under the age of five. Those studies that included adjusted correlation measurements for the most important confounding variables and which had an adequate population size were considered to be more relevant. The results concerning the relationship between gas energy sources and children's respiratory health were heterogeneous. Indoor air pollution from biomass combustion in the poorest countries was found to be an important risk factor for lower respiratory tract infections. Solvents involved in redecorating, DYI work, painting, and so forth, were found to be related to an increased risk for general respiratory problems. The distribution of papers depending on the pollution source showed a clear relationship with life-style and the level of development.

  5. Sources of indoor air pollution and respiratory health in preschool children.

    PubMed

    Fuentes-Leonarte, Virginia; Ballester, Ferran; Tenías, José Maria

    2009-01-01

    We carried out bibliographic searches in PubMed and Embase.com for the period from 1996 to 2008 with the aim of reviewing the scientific literature on the relationship between various sources of indoor air pollution and the respiratory health of children under the age of five. Those studies that included adjusted correlation measurements for the most important confounding variables and which had an adequate population size were considered to be more relevant. The results concerning the relationship between gas energy sources and children's respiratory health were heterogeneous. Indoor air pollution from biomass combustion in the poorest countries was found to be an important risk factor for lower respiratory tract infections. Solvents involved in redecorating, DYI work, painting, and so forth, were found to be related to an increased risk for general respiratory problems. The distribution of papers depending on the pollution source showed a clear relationship with life-style and the level of development. PMID:20168984

  6. Retrieval of air temperatures from crowd-sourced battery temperatures of cell phones

    NASA Astrophysics Data System (ADS)

    Overeem, Aart; Robinson, James; Leijnse, Hidde; Uijlenhoet, Remko; Steeneveld, Gert-Jan; Horn, Berthold K. P.

    2013-04-01

    Accurate air temperature observations are important for urban meteorology, for example to study the urban heat island and adverse effects of high temperatures on human health. The number of available temperature observations is often relatively limited. A new development is presented to derive temperature information for the urban canopy from an alternative source: cell phones. Battery temperature data were collected by users of an Android application for cell phones (opensignal.com). The application automatically sends battery temperature data to a server for storage. In this study, battery temperatures are averaged in space and time to obtain daily averaged battery temperatures for each city separately. A regression model, which can be related to a physical model, is employed to retrieve daily air temperatures from battery temperatures. The model is calibrated with observed air temperatures from a meteorological station of an airport located in or near the city. Time series of air temperatures are obtained for each city for a period of several months, where 50% of the data is for independent verification. Results are presented for Buenos Aires, London, Los Angeles, Paris, Mexico City, Moscow, Rome, and Sao Paulo. The evolution of the retrieved air temperatures often correspond well with the observed ones. The mean absolute error of daily air temperatures is less than 2 degrees Celsius, and the bias is within 1 degree Celsius. This shows that monitoring air temperatures employing an Android application holds great promise. Since 75% of the world's population has a cell phone, 20% of the land surface of the earth has cellular telephone coverage, and 500 million devices use the Android operating system, there is a huge potential for measuring air temperatures employing cell phones. This could eventually lead to real-time world-wide temperature maps.

  7. Classifying Sources Influencing Indoor Air Quality (IAQ) Using Artificial Neural Network (ANN).

    PubMed

    Saad, Shaharil Mad; Andrew, Allan Melvin; Shakaff, Ali Yeon Md; Saad, Abdul Rahman Mohd; Kamarudin, Azman Muhamad Yusof; Zakaria, Ammar

    2015-05-20

    Monitoring indoor air quality (IAQ) is deemed important nowadays. A sophisticated IAQ monitoring system which could classify the source influencing the IAQ is definitely going to be very helpful to the users. Therefore, in this paper, an IAQ monitoring system has been proposed with a newly added feature which enables the system to identify the sources influencing the level of IAQ. In order to achieve this, the data collected has been trained with artificial neural network or ANN--a proven method for pattern recognition. Basically, the proposed system consists of sensor module cloud (SMC), base station and service-oriented client. The SMC contain collections of sensor modules that measure the air quality data and transmit the captured data to base station through wireless network. The IAQ monitoring system is also equipped with IAQ Index and thermal comfort index which could tell the users about the room's conditions. The results showed that the system is able to measure the level of air quality and successfully classify the sources influencing IAQ in various environments like ambient air, chemical presence, fragrance presence, foods and beverages and human activity.

  8. Classifying Sources Influencing Indoor Air Quality (IAQ) Using Artificial Neural Network (ANN)

    PubMed Central

    Mad Saad, Shaharil; Melvin Andrew, Allan; Md Shakaff, Ali Yeon; Mohd Saad, Abdul Rahman; Muhamad Yusof @ Kamarudin, Azman; Zakaria, Ammar

    2015-01-01

    Monitoring indoor air quality (IAQ) is deemed important nowadays. A sophisticated IAQ monitoring system which could classify the source influencing the IAQ is definitely going to be very helpful to the users. Therefore, in this paper, an IAQ monitoring system has been proposed with a newly added feature which enables the system to identify the sources influencing the level of IAQ. In order to achieve this, the data collected has been trained with artificial neural network or ANN—a proven method for pattern recognition. Basically, the proposed system consists of sensor module cloud (SMC), base station and service-oriented client. The SMC contain collections of sensor modules that measure the air quality data and transmit the captured data to base station through wireless network. The IAQ monitoring system is also equipped with IAQ Index and thermal comfort index which could tell the users about the room’s conditions. The results showed that the system is able to measure the level of air quality and successfully classify the sources influencing IAQ in various environments like ambient air, chemical presence, fragrance presence, foods and beverages and human activity. PMID:26007724

  9. Locating and estimating air emissions from sources of styrene. Interim report

    SciTech Connect

    Campbell, D.

    1991-10-01

    To assist groups interested in inventorying air emissions of various potentially toxic substances, EPA is preparing a series of documents such as this to compile available information on sources and emission of these substances. The document deals specifically with styrene. Its intended audience includes Federal, State and local air pollution personnel and others interested in locating potential emitters of styrene and in making gross estimates of air emissions therefrom. The document presents information on: (1) the types of sources that may emit styrene; (2) process variations and release points that may be emitted within these sources; and (3) available emissions information indicating the potential for styrene releases into the air from each operation. The document is being released as an interim document pending incorporation of testing results from the U.S. EPA. The EPA is currently testing several unsaturated polyester resin fabricators who produce cultured marble bathroom fixtures. When the test results are available, the EPA will publish a final report including these data.

  10. Diagnostics Beamline for the SRF Gun Project

    SciTech Connect

    T. Kamps; V. Durr; K. Goldammer; D. Kramer; P. Kuske; J. Kuszynski; D. Lipka; F. Marhauser; T. Quast; D. Richter; U. Lehnert; P. Michel; J. Teichert; P. Evtushenko; I. Will

    2005-08-22

    A superconducting radio-frequency photo electron injector (SRF gun) is currently under construction by a collaboration of BESSY, DESY, FZR and MBI. The project aims at the design and setup of a CW SRF gun including a diagnostics beamline for the ELBE FEL and to address R&D issues on low emittance injectors for future light sources such as the BESSY FEL. Of critical importance for the injector performance is the control of the electron beam parameters. For this reason a compact diagnostics beamline is under development serving a multitude of operation settings ranging from low-charge (77pC), low-emittance (1 mm mrad) mode to high-charge (2.5nC) operation of the gun. For these operation modes beam dynamics simulations are resulting in boundary conditions for the beam instrumentation. Proven and mature technology is projected wherever possible, for example for current and beam position monitoring. The layout of the beam profile and emittance measurement systems is described. For the bunch length, which varies between 5 ps and 50 ps, two schemes using electro-optical sampling and Cherenkov radiation are detailed. The beam energy and energy spread is measured with a 180-degree spectrometer.

  11. High Intensity Polarized Electron Gun

    SciTech Connect

    Redwine, Robert P.

    2012-07-31

    The goal of the project was to investigate the possibility of building a very high intensity polarized electron gun for the Electron-Ion Collider. This development is crucial for the eRHIC project. The gun implements a large area cathode, ring-shaped laser beam and active cathode cooling. A polarized electron gun chamber with a large area cathode and active cathode cooling has been built and tested. A preparation chamber for cathode activation has been built and initial tests have been performed. Major parts for a load-lock chamber, where cathodes are loaded into the vacuum system, have been manufactured.

  12. Superconducting augmented rail gun (SARG)

    SciTech Connect

    Homan, C.G.; Cummings, C.E.; Fowler, C.M.

    1986-11-01

    Superconducting augmentation consists of a superconducting coil operating in the persistent mode closely coupled magnetically with a normally conducting rail gun. A theoretical investigation of the effect of this system on a rail gun has shown that two benefits occur. Projectile velocities and launch efficiencies increase significantly depending on the magnetic coupling between the rail and augmentation circuits. Previous work evaluated an idealized system by neglecting energy dissipation effects. In this paper, the authors extend the analysis to include the neglected terms and show improved actual launch efficiencies for the SARG configuration. In this paper, the authors discuss details of projectile design in depth and present preliminary results of rail gun performance.

  13. A source of electrical energy using an air-aluminum element (AAE)

    SciTech Connect

    Anisin, A.V.; Borisenok, V.A.; Potemkin, G.A.

    1996-04-01

    An air-aluminium element (AAE) is a chemical current source (CCS) with an aluminium anode and an oxygen gas-diffusion cathode. An AAE may be relegated to intermediate types of CCS, occupying a position between primary and fuel cells. The consumable material is aluminium, and the oxidizer is oxygen in the air coming from the external environment. The electrolyte is an aqueous solution of sodium chloride. Sea water may be used in this capacity. The end product of AAE operation is aluminium hydroxide, which can be regenerated into the initial anode aluminium, and is a non-toxic product.

  14. Outdoor air pollution in close proximity to a continuous point source

    NASA Astrophysics Data System (ADS)

    Klepeis, Neil E.; Gabel, Etienne B.; Ott, Wayne R.; Switzer, Paul

    Data are lacking on human exposure to air pollutants occurring in ground-level outdoor environments within a few meters of point sources. To better understand outdoor exposure to tobacco smoke from cigarettes or cigars, and exposure to other types of outdoor point sources, we performed more than 100 controlled outdoor monitoring experiments on a backyard residential patio in which we released pure carbon monoxide (CO) as a tracer gas for continuous time periods lasting 0.5-2 h. The CO was emitted from a single outlet at a fixed per-experiment rate of 120-400 cc min -1 (˜140-450 mg min -1). We measured CO concentrations every 15 s at up to 36 points around the source along orthogonal axes. The CO sensors were positioned at standing or sitting breathing heights of 2-5 ft (up to 1.5 ft above and below the source) and at horizontal distances of 0.25-2 m. We simultaneously measured real-time air speed, wind direction, relative humidity, and temperature at single points on the patio. The ground-level air speeds on the patio were similar to those we measured during a survey of 26 outdoor patio locations in 5 nearby towns. The CO data exhibited a well-defined proximity effect similar to the indoor proximity effect reported in the literature. Average concentrations were approximately inversely proportional to distance. Average CO levels were approximately proportional to source strength, supporting generalization of our results to different source strengths. For example, we predict a cigarette smoker would cause average fine particle levels of approximately 70-110 μg m -3 at horizontal distances of 0.25-0.5 m. We also found that average CO concentrations rose significantly as average air speed decreased. We fit a multiplicative regression model to the empirical data that predicts outdoor concentrations as a function of source emission rate, source-receptor distance, air speed and wind direction. The model described the data reasonably well, accounting for ˜50% of the log

  15. Reduction of Gun Erosion and Correlation of Gun Erosion Measurements

    NASA Technical Reports Server (NTRS)

    Bogdanoff, Dave; Wercinski, Paul (Technical Monitor)

    1997-01-01

    Gun barrel erosion is serious problem with two-stage light gas guns. Excessive barrel erosion can lead to poor or failed launches and frequent barrel changes, with the corresponding down time. Also, excessive barrel erosion can limit the maximum velocity obtainable by loading down the hydrogen working gas with eroded barrel material. Guided by a CFD code, the operating conditions of the Ames 0.5-inch gun were modified to reduce barrel erosion. The changes implemented included: (1) reduction in the piston mass, powder mass and hydrogen fill pressure; and (2) reduction in pump tube volume, while maintaining hydrogen mass. The latter change was found, in particular, to greatly reduce barrel erosion. For muzzle velocity ranges of 6.1 - 6.9 km/sec, the barrel erosion was reduced by a factor of 10. Even for the higher muzzle velocity range of 7.0 - 8.2 km/sec, the barrel erosion was reduced by a factor of 4. Gun erosion data from the Ames 0.5-inch, 1.0-inch, and 1.5-inch guns operated over a wide variety of launch conditions was examined and it was found that this data could be correlated using four different parameters: normalized powder charge energy, normalized hydrogen energy density, normalized pump tube volume and barrel diameter. The development of the correlation and the steps used to collapse the experimental data are presented. Over a certain parameter range in the correlation developed, the barrel erosion per shot is found to increase very rapidly. The correlation should prove useful in the selection of gun operating conditions and the design of new guns. Representative shapes of eroded gun barrels are also presented.

  16. Diagnostic air quality model evaluation of source-specific primary and secondary fine particulate carbon.

    PubMed

    Napelenok, Sergey L; Simon, Heather; Bhave, Prakash V; Pye, Havala O T; Pouliot, George A; Sheesley, Rebecca J; Schauer, James J

    2014-01-01

    Ambient measurements of 78 source-specific tracers of primary and secondary carbonaceous fine particulate matter collected at four midwestern United States locations over a full year (March 2004-February 2005) provided an unprecedented opportunity to diagnostically evaluate the results of a numerical air quality model. Previous analyses of these measurements demonstrated excellent mass closure for the variety of contributing sources. In this study, a carbon-apportionment version of the Community Multiscale Air Quality (CMAQ) model was used to track primary organic and elemental carbon emissions from 15 independent sources such as mobile sources and biomass burning in addition to four precursor-specific classes of secondary organic aerosol (SOA) originating from isoprene, terpenes, aromatics, and sesquiterpenes. Conversion of the source-resolved model output into organic tracer concentrations yielded a total of 2416 data pairs for comparison with observations. While emission source contributions to the total model bias varied by season and measurement location, the largest absolute bias of -0.55 μgC/m(3) was attributed to insufficient isoprene SOA in the summertime CMAQ simulation. Biomass combustion was responsible for the second largest summertime model bias (-0.46 μgC/m(3) on average). Several instances of compensating errors were also evident; model underpredictions in some sectors were masked by overpredictions in others.

  17. Diagnostic air quality model evaluation of source-specific primary and secondary fine particulate carbon.

    PubMed

    Napelenok, Sergey L; Simon, Heather; Bhave, Prakash V; Pye, Havala O T; Pouliot, George A; Sheesley, Rebecca J; Schauer, James J

    2014-01-01

    Ambient measurements of 78 source-specific tracers of primary and secondary carbonaceous fine particulate matter collected at four midwestern United States locations over a full year (March 2004-February 2005) provided an unprecedented opportunity to diagnostically evaluate the results of a numerical air quality model. Previous analyses of these measurements demonstrated excellent mass closure for the variety of contributing sources. In this study, a carbon-apportionment version of the Community Multiscale Air Quality (CMAQ) model was used to track primary organic and elemental carbon emissions from 15 independent sources such as mobile sources and biomass burning in addition to four precursor-specific classes of secondary organic aerosol (SOA) originating from isoprene, terpenes, aromatics, and sesquiterpenes. Conversion of the source-resolved model output into organic tracer concentrations yielded a total of 2416 data pairs for comparison with observations. While emission source contributions to the total model bias varied by season and measurement location, the largest absolute bias of -0.55 μgC/m(3) was attributed to insufficient isoprene SOA in the summertime CMAQ simulation. Biomass combustion was responsible for the second largest summertime model bias (-0.46 μgC/m(3) on average). Several instances of compensating errors were also evident; model underpredictions in some sectors were masked by overpredictions in others. PMID:24245475

  18. Design, Construction and Operation of a Light Gas Gun

    NASA Astrophysics Data System (ADS)

    Borg, John

    2005-11-01

    In order to conduct Richtmyer-Meshkov instability experiments in shock accelerated thin liquid sheets, a light gas gun was designed and constructed at Marquette University. This paper contains the basic predictions and construction techniques utilized in the design and operation of a double diaphragm light gas gun. The compressed air gas gun is used to accelerate a nylon projectile up to a velocity of 300 m/s. Pretest simulations were performed using two different hydrodynamic computational codes in order to simulate the inboard gas dynamics and projectile velocity. These simulations are compared with post test projectile velocity data. The simulations compare favorably to the data, including the one-dimensional calculations which do not account for frictional losses or diameter changes between the breech and barrel. Finally, both the computational simulations and the experimental measurements are compared to simple analytical predictions of the projectile velocity.

  19. Field Test of High Efficiency Residential Buildings with Ground-source and Air-source Heat Pump Systems

    SciTech Connect

    Ally, Moonis Raza; Munk, Jeffrey D; Baxter, Van D

    2011-01-01

    This paper describes the field performance of space conditioning and water heating equipment in four single-family residential structures with advanced thermal envelopes. Each structure features a different, advanced thermal envelope design: structural insulated panel (SIP); optimum value framing (OVF); insulation with embedded phase change materials (PCM) for thermal storage; and exterior insulation finish system (EIFS). Three of the homes feature ground-source heat pumps (GSHPs) for space conditioning and water heating while the fourth has a two-capacity air-source heat pump (ASHP) and a heat pump water heater (HPWH). Two of the GCHP-equipped homes feature horizontal ground heat exchange (GHX) loops that utillize the existing foundation and utility service trenches while the third features a vertical borehole with vertical u-tube GHX. All of the houses were operated under the same simulated occupancy conditions. Operational data on the house HVAC/Water heating (WH) systems are presented and factors influencing overall performance are summarized.

  20. The Internal Ballistics of an Air Gun

    ERIC Educational Resources Information Center

    Denny, Mark

    2011-01-01

    The internal ballistics of a firearm or artillery piece considers the pellet, bullet, or shell motion while it is still inside the barrel. In general, deriving the muzzle speed of a gunpowder firearm from first principles is difficult because powder combustion is fast and it very rapidly raises the temperature of gas (generated by gunpowder…

  1. Direct measurement of air kerma rate in air from CDCS J-type caesium-137 therapy sources using a Farmer ionization chamber.

    PubMed

    Poynter, A J

    2000-04-01

    A simple method for directly measuring the reference air kerma rate from J-type 137Cs sources using a Farmer 2571 chamber has been evaluated. The method is useful as an independent means of verifying manufacturers' test data.

  2. 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.

  3. Megacity and country emissions from combustion sources-Buenos Aires-Argentina

    NASA Astrophysics Data System (ADS)

    Dawidowski, L.; Gomez, D.; Matranga, M.; D'Angiola, A.; Oreggioni, G.

    2010-12-01

    Historic time series (1970-2006) emissions of greenhouse gases and air pollutants arising from stationary and mobile combustion sources were estimated at national level for Argentina and at regional level for the metropolitan area of Buenos Aires (MABA). All emissions were estimated using a bottom-up approach following the IPCC good practice guidance. For mobile sources, national emissions include all transport categories. Regional emissions account thus far only for on-road. For national emissions, methodologies and guidance by the IPCC were employed, applying the highest possible tier and using: i)country-specific emission factors for carbon and sulphur and technology-based information for other species, ii)activity data from energy balance series (1970-2007), and iii)complementary information concerning the non-energy use of fuels. Regional emissions in 2006 were estimated in-depth using a technology-based approach for the city of Buenos Aires (CBA) and the 24 neighboring districts composing the MABA. A regional emissions factors database was developed to better characterize Latin American fleets and driving conditions employing COPERT III-IV algorithms and emission factors measured in dynamometers and circulating vehicles in Argentina, Brazil, Chile and Colombia. Past emissions were back estimated from 2005 to 1970 using the best available information, which differs greatly among categories, spatial disaggregation and time periods. The time series of stationary and mobile combustion sources at the national and regional level allowed the identification of distinct patterns. National greenhouse gas emissions in 2006 amounted to ~ 150 million ton CO2-equivalent, 70% of which were contributed by stationary sources. On-road transport was the major contributor within mobile sources (28.1 %). The increasing emissions trends are dominated by on-road transport, agriculture and residential categories while the variability is largely associated with energy industries

  4. An active expriments with electron gun on the microsatellite

    NASA Astrophysics Data System (ADS)

    Dokukin, V.; Ruzhin, Yu.

    Plasma radio emission in the presence of energetic particle fluxes is a very informative source of knowledge about plasma processes and its parameters in the interaction region. Now there is a big experience of work with election beams in the Earth ionosphere. The new generation of spacecrafts- micro and small satellites give us rather chip possibilities to carry out space orbital experiments. But there is an obstacle to do an active experiments at microsatellite with injection of electron beam-the limited onboard power source. Typically it requires at least tens of Watts to heat the cathode of electron gun and to accelerate the electrons of the beam. The proposal is made to apply ``solar'' electron gun with ``zero'' consumption from satellite powersuppliment. Such type of electron gun could be applied for space experiments at near Earth orbits and for solar or planetary missions.

  5. The polarized SRF gun experiment

    SciTech Connect

    Kewisch,J.; Ben-Zvi, I.; Rao, T.; Burrill, A.; Pate, D.; Todd, R.; Wang, E.; Bluem, H.; Holmes, D.; Shultheiss, T.

    2008-10-01

    An experiment is under way to prove the feasibility of a super-conducting RF gun for the production of polarized electrons. We report on the progress of the experiment and on simulations predicting the possibility of success.

  6. NASA-Ames vertical gun

    NASA Technical Reports Server (NTRS)

    Schultz, P. H.

    1984-01-01

    A national facility, the NASA-Ames vertical gun range (AVGR) has an excellent reputation for revealing fundamental aspects of impact cratering that provide important constraints for planetary processes. The current logistics in accessing the AVGR, some of the past and ongoing experimental programs and their relevance, and the future role of this facility in planetary studies are reviewed. Publications resulting from experiments with the gun (1979 to 1984) are listed as well as the researchers and subjects studied.

  7. PAH air pollution at a Portuguese urban area: carcinogenic risks and sources identification.

    PubMed

    Slezakova, K; Pires, J C M; Castro, D; Alvim-Ferraz, M C M; Delerue-Matos, C; Morais, S; Pereira, M C

    2013-06-01

    This study aimed to characterize air pollution and the associated carcinogenic risks of polycyclic aromatic hydrocarbon (PAHs) at an urban site, to identify possible emission sources of PAHs using several statistical methodologies, and to analyze the influence of other air pollutants and meteorological variables on PAH concentrations.The air quality and meteorological data were collected in Oporto, the second largest city of Portugal. Eighteen PAHs (the 16 PAHs considered by United States Environment Protection Agency (USEPA) as priority pollutants, dibenzo[a,l]pyrene, and benzo[j]fluoranthene) were collected daily for 24 h in air (gas phase and in particles) during 40 consecutive days in November and December 2008 by constant low-flow samplers and using polytetrafluoroethylene (PTFE) membrane filters for particulate (PM10 and PM2.5 bound) PAHs and pre-cleaned polyurethane foam plugs for gaseous compounds. The other monitored air pollutants were SO2, PM10, NO2, CO, and O3; the meteorological variables were temperature, relative humidity, wind speed, total precipitation, and solar radiation. Benzo[a]pyrene reached a mean concentration of 2.02 ng m(-3), surpassing the EU annual limit value. The target carcinogenic risks were equal than the health-based guideline level set by USEPA (10(-6)) at the studied site, with the cancer risks of eight PAHs reaching senior levels of 9.98 × 10(-7) in PM10 and 1.06 × 10(-6) in air. The applied statistical methods, correlation matrix, cluster analysis, and principal component analysis, were in agreement in the grouping of the PAHs. The groups were formed according to their chemical structure (number of rings), phase distribution, and emission sources. PAH diagnostic ratios were also calculated to evaluate the main emission sources. Diesel vehicular emissions were the major source of PAHs at the studied site. Besides that source, emissions from residential heating and oil refinery were identified to contribute to PAH levels at

  8. Turret-type electron gun for EBM-8000

    NASA Astrophysics Data System (ADS)

    Miyamoto, Nobuo; Kendall, Rodney; Saito, Kenichi

    2013-09-01

    To reduce down time associated with routine cathode replacement we developed a turret-type electron gun for our electron beam mask writer, EBM-8000. This enables us to exchange cathodes without venting the gun to atmosphere, thereby reducing the downtime for cathode replacement by 80% compared to conventional single-cathode guns. Two key elements were considered in developing the turret-type electron gun: reducing fluctuation in beam current, and eliminating discharge sources. Reducing fluctuation in beam current is one of the most important elements because it has an impact to critical CD accuracy. In EBM-8000, the current fluctuation must be 0.1% (3s) or less to attain the CD accuracy specification. We will explain how the beam stability is realized. Special treatment to eliminate discharge sources is necessary to realize long-term stability of the electron gun. We devised a conditioning sequence which repeatedly increases and decreases the voltage applied to the barrel in N2 atmosphere. This conditioning sequence allowed us to dramatically decrease the probability of discharges, allowing us to achieve long-term stability operation.

  9. Development of PM2.5 source impact spatial fields using a hybrid source apportionment air quality model

    NASA Astrophysics Data System (ADS)

    Ivey, C. E.; Holmes, H. A.; Hu, Y. T.; Mulholland, J. A.; Russell, A. G.

    2015-07-01

    An integral part of air quality management is knowledge of the impact of pollutant sources on ambient concentrations of particulate matter (PM). There is also a growing desire to directly use source impact estimates in health studies; however, source impacts cannot be directly measured. Several limitations are inherent in most source apportionment methods motivating the development of a novel hybrid approach that is used to estimate source impacts by combining the capabilities of receptor models (RMs) and chemical transport models (CTMs). The hybrid CTM-RM method calculates adjustment factors to refine the CTM-estimated impact of sources at monitoring sites using pollutant species observations and the results of CTM sensitivity analyses, though it does not directly generate spatial source impact fields. The CTM used here is the Community Multiscale Air Quality (CMAQ) model, and the RM approach is based on the chemical mass balance (CMB) model. This work presents a method that utilizes kriging to spatially interpolate source-specific impact adjustment factors to generate revised CTM source impact fields from the CTM-RM method results, and is applied for January 2004 over the continental United States. The kriging step is evaluated using data withholding and by comparing results to data from alternative networks. Data withholding also provides an estimate of method uncertainty. Directly applied (hybrid, HYB) and spatially interpolated (spatial hybrid, SH) hybrid adjustment factors at withheld observation sites had a correlation coefficient of 0.89, a linear regression slope of 0.83 ± 0.02, and an intercept of 0.14 ± 0.02. Refined source contributions reflect current knowledge of PM emissions (e.g., significant differences in biomass burning impact fields). Concentrations of 19 species and total PM2.5 mass were reconstructed for withheld observation sites using HYB and SH adjustment factors. The mean concentrations of total PM2.5 at withheld observation sites were

  10. Sewer Gas: An Indoor Air Source of PCE to Consider During Vapor Intrusion Investigations

    PubMed Central

    Pennell, Kelly G.; Scammell, Madeleine Kangsen; McClean, Michael D.; Ames, Jennifer; Weldon, Brittany; Friguglietti, Leigh; Suuberg, Eric M.; Shen, Rui; Indeglia, Paul A.; Heiger-Bernays, Wendy J.

    2013-01-01

    The United States Environmental Protection Agency (USEPA) is finalizing its vapor intrusion guidelines. One of the important issues related to vapor intrusion is background concentrations of volatile organic chemicals (VOCs) in indoor air, typically attributed to consumer products and building materials. Background concentrations can exist even in the absence of vapor intrusion and are an important consideration when conducting site assessments. In addition, the development of accurate conceptual models that depict pathways for vapor entry into buildings is important during vapor intrusion site assessments. Sewer gas, either as a contributor to background concentrations or as part of the site conceptual model, is not routinely evaluated during vapor intrusion site assessments. The research described herein identifies an instance where vapors emanating directly from a sanitary sewer pipe within a residence were determined to be a source of tetrachloroethylene (PCE) detected in indoor air. Concentrations of PCE in the bathroom range from 2.1 to 190 ug/m3 and exceed typical indoor air concentrations by orders of magnitude resulting in human health risk classified as an “Imminent Hazard” condition. The results suggest that infiltration of sewer gas resulted in PCE concentrations in indoor air that were nearly two-orders of magnitude higher as compared to when infiltration of sewer gas was not known to be occurring. This previously understudied pathway whereby sewers serve as sources of PCE (and potentially other VOC) vapors is highlighted. Implications for vapor intrusion investigations are also discussed. PMID:23950637

  11. Volatile organic compounds (VOCs) in air from Nisyros Island (Dodecanese Archipelago, Greece): Natural versus anthropogenic sources.

    PubMed

    Tassi, F; Capecchiacci, F; Giannini, L; Vougioukalakis, G E; Vaselli, O

    2013-09-01

    This study presents the chemical composition of VOCs in air and gas discharges collected at Nisyros Island (Dodecanese Archipelago, Greece). The main goals are i) to discriminate between natural and anthropogenic VOC sources and ii) to evaluate their impact on local air quality. Up to 63 different VOCs were recognized and quantitatively determined in 6 fumaroles and 19 air samples collected in the Lakki caldera, where fumarolic emissions are located, and the outer ring of the island, including the Mandraki village and the main harbor. Air samples from the crater area show significant concentrations of alkanes, alkenes, cyclic, aromatics, and S- and O-bearing heterocycles directly deriving from the hydrothermal system, as well as secondary O-bearing compounds from oxidation of primary VOCs. At Mandraki village, C6H6/Σ(methylated aromatics) and Σ(linear)/Σ(branched) alkanes ratios <1 allow to distinguish an anthropogenic source related to emissions from outlet pipes of touristic and private boats and buses. PMID:23747819

  12. Scuba tanks as a compressed air source in positive-pressure ventilation.

    PubMed

    Stewart, T

    1992-06-01

    Throughout the developing world there is a general problem of ensuring regular deliveries of medical supplies to hospitals. This includes the supply of compressed gases. At one regional hospital in Vanuatu, we were faced with the problem of how to provide economically a source of compressed gas at regulated pressure to drive an anaesthetic ventilator. We eventually adapted the output from a Scuba cylinder for this purpose. This paper describes the simple modifications necessary and suggests other uses for this source of compressed air that could be implemented in hospitals with small to medium case loads and access to a diving compressor.

  13. Characterization of an atmospheric pressure air plasma source for polymer surface modification

    NASA Astrophysics Data System (ADS)

    Yang, Shujun; Tang, Jiansheng

    2013-10-01

    An atmospheric pressure air plasma source was generated through dielectric barrier discharge (DBD). It was used to modify polyethyleneterephthalate (PET) surfaces with very high throughput. An equivalent circuit model was used to calculate the peak average electron density. The emission spectrum from the plasma was taken and the main peaks in the spectrum were identified. The ozone density in the down plasma region was estimated by Absorption Spectroscopy. NSF and ARC-ODU

  14. Air-Source Integrated Heat Pump for Near-Zero Energy Houses: Technology Status Report

    SciTech Connect

    Murphy, Richard W; Rice, C Keith; Baxter, Van D; Craddick, William G

    2007-07-01

    This report documents the development of an air-source integrated heat pump (AS-IHP) through the third quarter of FY2007. It describes the design, analyses and testing of the AS-IHP, and provides performance specifications for a field test prototype and proposed control strategy. The results obtained so far continue to support the AS-IHP being a promising candidate to meet the energy service needs for DOE's development of a Zero Energy Home (ZEH) by the year 2020.

  15. RF study and 3-D simulations of a side-coupling thermionic RF-gun

    NASA Astrophysics Data System (ADS)

    Rimjaem, S.; Kusoljariyakul, K.; Thongbai, C.

    2014-02-01

    A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012©. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

  16. Source-specific fine particulate air pollution and systemic inflammation in ischaemic heart disease patients

    PubMed Central

    Siponen, Taina; Yli-Tuomi, Tarja; Aurela, Minna; Dufva, Hilkka; Hillamo, Risto; Hirvonen, Maija-Riitta; Huttunen, Kati; Pekkanen, Juha; Pennanen, Arto; Salonen, Iiris; Tiittanen, Pekka; Salonen, Raimo O; Lanki, Timo

    2015-01-01

    Objective To compare short-term effects of fine particles (PM2.5; aerodynamic diameter <2.5 µm) from different sources on the blood levels of markers of systemic inflammation. Methods We followed a panel of 52 ischaemic heart disease patients from 15 November 2005 to 21 April 2006 with clinic visits in every second week in the city of Kotka, Finland, and determined nine inflammatory markers from blood samples. In addition, we monitored outdoor air pollution at a fixed site during the study period and conducted a source apportionment of PM2.5 using the Environmental Protection Agency's model EPA PMF 3.0. We then analysed associations between levels of source-specific PM2.5 and markers of systemic inflammation using linear mixed models. Results We identified five source categories: regional and long-range transport (LRT), traffic, biomass combustion, sea salt, and pulp industry. We found most evidence for the relation of air pollution and inflammation in LRT, traffic and biomass combustion; the most relevant inflammation markers were C-reactive protein, interleukin-12 and myeloperoxidase. Sea salt was not positively associated with any of the inflammatory markers. Conclusions Results suggest that PM2.5 from several sources, such as biomass combustion and traffic, are promoters of systemic inflammation, a risk factor for cardiovascular diseases. PMID:25479755

  17. A Investigation of the Plasma Jet as AN Underwater Acoustic Source.

    NASA Astrophysics Data System (ADS)

    Smith, Robert David

    The plasma jet, a commonly used ignition device, has been investigated as a source of acoustic energy suitable for sub-bottom profiling. Named the plasma gun, the device discharges electrical energy in a cylindrical arc ignited in a gaseous environment surrounded by water. When the arc energy evaporates water, it produces a rapidly expanding vapor bubble that creates the acoustic pressure wave. Acoustic properties of the device are similar to small explosives, and to electric sparkers. Multiple bubble oscillations, a problem of explosive-type sources, are generally less troublesome for the plasma gun than with the sparker sources. Some degree of frequency control of the acoustic pulse is possible if proper values are selected for the electrical circuit components and for the total stored electrical energy. Peak acoustic pressures are controlled both by the total electric energy and by the rate it is delivered to the arc. These quantities are determined by capacitance, inductance, and charging voltage. Frequency components of the primary pressure pulse depend on the arc discharge frequency and on the immersion depth of the device. The bubble period depends primarily on the amount of energy discharged into the water; this in turn is proportional to the total stored electrical energy. The plasma gun has been compared to small air guns, pingers, sparkers, and boomers. Sub-bottom profiles obtained show penetration less than the 1 in^3 air gun but with more resolution. Stored energy in the plasma gun, however, was nearly five times less. Penetration was equal and resolution better than electric sparkers of the same energy. Penetration was better and resolution poorer than the pinger, and resolution poorer and penetration slightly better than the boomer source. Except for the sparkers, which used the same power supply, the plasma gun has a decided advantage in equipment size and ease of deployment.

  18. Experimental derivation of the fluence non-uniformity correction for air kerma near brachytherapy linear sources

    SciTech Connect

    Vianello, E. A.; Almeida, C. E. de

    2008-07-15

    In brachytherapy, one of the elements to take into account for measurements free in air is the non-uniformity of the photon fluence due to the beam divergence that causes a steep dose gradient near the source. The correction factors for this phenomenon have been usually evaluated by two available theories by Kondo and Randolph [Radiat. Res. 13, 37-60 (1960)] and Bielajew [Phys. Med. Biol. 35, 517-538 (1990)], both conceived for point sources. This work presents the experimental validation of the Monte Carlo calculations made by Rodriguez and deAlmeida [Phys. Med. Biol. 49, 1705-1709 (2004)] for the non-uniformity correction specifically for a Cs-137 linear source measured using a Farmer type ionization chamber. The experimental values agree very well with the Monte Carlo calculations and differ from the results predicted by both theoretical models widely used. This result confirms that for linear sources there are some important differences at short distances from the source and emphasizes that those theories should not be used for linear sources. The data provided in this study confirm the limitations of the mentioned theories when linear sources are used. Considering the difficulties and uncertainties associated with the experimental measurements, it is recommended to use the Monte Carlo data to assess the non-uniformity factors for linear sources in situations that require this knowledge.

  19. Sources of indoor air pollution in New York City residences of asthmatic children.

    PubMed

    Habre, Rima; Coull, Brent; Moshier, Erin; Godbold, James; Grunin, Avi; Nath, Amit; Castro, William; Schachter, Neil; Rohr, Annette; Kattan, Meyer; Spengler, John; Koutrakis, Petros

    2014-01-01

    Individuals spend ∼90% of their time indoors in proximity to sources of particulate and gaseous air pollutants. The sulfur tracer method was used to separate indoor concentrations of particulate matter (PM) PM2.5 mass, elements and thermally resolved carbon fractions by origin in New York City residences of asthmatic children. Enrichment factors relative to sulfur concentrations were used to rank species according to the importance of their indoor sources. Mixed effects models were used to identify building characteristics and resident activities that contributed to observed concentrations. Significant indoor sources were detected for OC1, Cl, K and most remaining OC fractions. We attributed 46% of indoor PM2.5 mass to indoor sources related to OC generation indoors. These sources include cooking (NO2, Si, Cl, K, OC4 and OP), cleaning (most OC fractions), candle/incense burning (black carbon, BC) and smoking (K, OC1, OC3 and EC1). Outdoor sources accounted for 28% of indoor PM2.5 mass, mainly photochemical reaction products, metals and combustion products (EC, EC2, Br, Mn, Pb, Ni, Ti, V and S). Other indoor sources accounted for 26% and included re-suspension of crustal elements (Al, Zn, Fe, Si and Ca). Indoor sources accounted for ∼72% of PM2.5 mass and likely contributed to differences in the composition of indoor and outdoor PM2.5 exposures. PMID:24169876

  20. Sources of indoor air pollution in New York City residences of asthmatic children.

    PubMed

    Habre, Rima; Coull, Brent; Moshier, Erin; Godbold, James; Grunin, Avi; Nath, Amit; Castro, William; Schachter, Neil; Rohr, Annette; Kattan, Meyer; Spengler, John; Koutrakis, Petros

    2014-01-01

    Individuals spend ∼90% of their time indoors in proximity to sources of particulate and gaseous air pollutants. The sulfur tracer method was used to separate indoor concentrations of particulate matter (PM) PM2.5 mass, elements and thermally resolved carbon fractions by origin in New York City residences of asthmatic children. Enrichment factors relative to sulfur concentrations were used to rank species according to the importance of their indoor sources. Mixed effects models were used to identify building characteristics and resident activities that contributed to observed concentrations. Significant indoor sources were detected for OC1, Cl, K and most remaining OC fractions. We attributed 46% of indoor PM2.5 mass to indoor sources related to OC generation indoors. These sources include cooking (NO2, Si, Cl, K, OC4 and OP), cleaning (most OC fractions), candle/incense burning (black carbon, BC) and smoking (K, OC1, OC3 and EC1). Outdoor sources accounted for 28% of indoor PM2.5 mass, mainly photochemical reaction products, metals and combustion products (EC, EC2, Br, Mn, Pb, Ni, Ti, V and S). Other indoor sources accounted for 26% and included re-suspension of crustal elements (Al, Zn, Fe, Si and Ca). Indoor sources accounted for ∼72% of PM2.5 mass and likely contributed to differences in the composition of indoor and outdoor PM2.5 exposures.

  1. Source assessment of particulate air pollutants measured at the southwest european coast

    NASA Astrophysics Data System (ADS)

    Pio, Casimiro A.; Castro, Luis M.; Cerqueira, Mario A.; Santos, Isabel M.; Belchior, Filipa; Salgueiro, Maria L.

    Aerosol particles and gaseous species were measured in air masses transported to the west coast of Portugal, between November 1993 and August 1994. Samples were taken during four monitoring campaigns distributed along the various seasons of the year, integrated in the EC Project: BMCAPE. Aerosol particles were collected with separation in two size fractions and analysed in relation to total mass, water soluble ions, trace elements and black/organic carbon. Local micro-meteorological parameters and air mass backward trajectories were compared with analytical results in order to define characteristic air mass types and to evaluate the origin of pollutants. Average concentrations on the Portuguese west coast, even in maritime air masses, are higher than values observed in remote oceanic locations. This is probably a consequence of continental European air masses recirculation through the eastern Atlantic Ocean, reinforced by situations of mesoscale transport from the Iberian Peninsula. Principal Component Analysis permitted the identification of five source groups for the fine and coarse aerosol fractions, namely combustion plus road traffic, sea salt spray, secondary aerosol production, soil and possibly non-ferrous metallurgy industries. In the aerosol fine fraction road traffic and combustion contribute on average with 25% of the total fine aerosol mass, while sea spray and secondary production represent 14% and 31%, respectively of the mass loading. Sea spray is by far the major contributor to the coarse fraction with an average of 88% of the suspended coarse aerosol mass.

  2. Analysis of air quality observations with the aid of the source-receptor relationship approach.

    PubMed

    Astitha, Marina; Kallos, George; Mihalopoulos, Nikos

    2005-04-01

    In this study, an attempt was made to analyze time series of air quality measurements (O3, SO2, SO4(2-), NOx) conducted at a remote place in the eastern Mediterranean (Finokalia at Crete Island in 1999) to obtain concrete information on potential contributions from emission sources. For the definition of a source-receptor relationship, advanced meteorological and dispersion models appropriate to identify "areas of influence" have been used. The model tools used are the Regional Atmospheric Modeling System and the Lagrangian-type particle dispersion model (forward and backward in time), with capabilities to derive influence functions and definition of "areas of influence." When high levels of pollutants have been measured at the remote location of Finokalia, particles are released from this location (receptor) and traced backward in time. The influence function derived from particle distributions characterizes dispersion conditions in the atmosphere and also provides information on potential contributions from emission sources within the modeling domain to this high concentration. As was shown in the simulation results, the experimental site of Finokalia in Crete is influenced during the selected case studies, primarily by pollutants emitted from the urban conglomerate of Athens. Secondarily, it is influenced by polluted air masses arriving from Italy and/or the Black Sea Region. For some specific cases, air pollutants monitored at Finokalia were possibly related to war activities in the West Balkan Region (Kosovo). PMID:15887895

  3. Spatial variations, temporal trends, and emission sources of air pollutants in seven cities of northern China

    NASA Astrophysics Data System (ADS)

    LI, WEI; TAO, SHU; WANG, CHEN

    2014-05-01

    Particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), and the derivatives of PAHs (nitro-PAHs and oxy-PAHs) were measured each month between April, 2010 and March, 2011 in seven large cities (18 sites) in the ambient air of northern China. Similarities in the concentrations of PM, PAHs and oxy-PAHs between rural village and urban area are found, indicating the severe air pollution in the rural villages and strong contribution of solid fuels combustion. Higher nitro-PAHs concentrations in the cities than those in the rural area suggests the influence of motor vehicles, both on primary emission and secondary formation. Without local emission sources, pollutants levels in the rural field area are the lowest. Air pollution in the less developed west China is as severe as that in the east with more population and urbanization, both heavier than that in the coastal area. Such spatial patterns are caused by differences in the sources of contaminants and the removal process. A strong seasonality of all pollutants with higher concentrations in winter and lower in summer is observed due to large heating demand for solid fuel combustion in winter and rich precipitation in summer. Natural sources such as sandstorms also take effects on the spatial distribution and temporal trend of PM.

  4. 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. PMID:24783322

  5. 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.

  6. 23 GHz ferroelectric electron gun based gyrotron

    NASA Astrophysics Data System (ADS)

    Ben-Moshe, R.; Einat, M.

    2011-04-01

    Ferroelectric cathodes have been explored as an alternative electron source for microwave tubes. Past experiments have demonstrated operation at frequencies of 2-10 GHz. Since the ferroelectric cathode is based on surface plasma, the relatively high energy spread limits the tube operation frequency. Hence, the possibility to obtain higher frequencies remained questionable. In this experimental work a gyrotron oscillator was designed with the operation frequency increased toward that of millimeter waves. A cylindrical tube with a cutoff frequency of ˜22 GHz was integrated to a ferroelectric electron gun. Pulses of ˜0.5 μs duration with a frequency of 23 GHz were obtained.

  7. JV Task 86 - Identifying the Source of Benzene in Indoor Air Using Different Compound Classes from TO-15 Data

    SciTech Connect

    Steven B. Hawthorne

    2007-04-15

    Volatile organic compound (VOC) data that had already been collected using EPA method TO-15 at four different sites under regulatory scrutiny (a school, strip mall, apartment complex, and business/residential neighborhood) were evaluated to determine whether the source of indoor air benzene was outdoor air or vapor intrusion from contaminated soil. Both the use of tracer organics characteristic of different sources and principal component statistical analysis demonstrated that the source of indoor air at virtually all indoor sampling locations was a result of outdoor air, and not contaminated soil in and near the indoor air-sampling locations. These results show that proposed remediation activities to remove benzene-contaminated soil are highly unlikely to reduce indoor air benzene concentrations. A manuscript describing these results is presently being prepared for submission to a peer-reviewed journal.

  8. Mapping Air Pollution Concentrations and Sources in China from Ground-Level Observations

    NASA Astrophysics Data System (ADS)

    Rohde, R. A.; Muller, R. A.

    2014-12-01

    China has recently established an extensive air quality monitoring system with over 1500 sites providing hourly data on airborne particulate matter (PM2.5 / PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO). Based on Kriging interpolation of these surface data, we derive a detailed map of air pollution across the eastern half of China. In northern and central China, the pollution is widespread; contrary to popular belief, pollution is not simply localized to major cities such as Beijing, Shanghai, or Chongqing, or in geologic basins. Pollution levels are lower in southern China, in part due to frequent rains. By incorporating wind measurements and estimating pollution transport, we also infer source distributions for key pollutants. Sources are widespread, but many of the largest sources are often situated in or near major population centers. A northeast corridor extending from near Shanghai to north of Beijing includes many of the most significant pollution sources in China. Roughly 5% of the study region accounts for 25% of observed particulate matter emissions. During the analysis period, roughly half of the population of China was subjected to a long-term average pollution level in the unhealthy range, according to standards used by the US Environmental Protection Agency. In addition, nearly all of China's population (>90%) was exposed to unhealthy levels of air pollution at least some of the time. Based on health impact estimates from the Huai River Study, we estimate that the observed levels of particulate matter pollution contribute to about 1.4 million deaths every year in China, about 3500 per day, in agreement with prior estimates. Identification of sources from pollution data was facilitated by the reporting of hourly measurements, and we encourage other nations around the world to follow China's example and provide such time-resolved data.

  9. Large Bore Powder Gun Qualification (U)

    SciTech Connect

    Rabern, Donald A.; Valdiviez, Robert

    2012-04-02

    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 been 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.

  10. Smog O3 Production Rate in California Air: Marker Compounds Allow Checks on Source Attribution to Fire and Other Sources

    NASA Astrophysics Data System (ADS)

    Chatfield, R. B.; Esswein, R. F.; Cai, C.; Kaduwela, A.; Kulkarni, S.; Blake, D. R.; Weinheimer, A. J.; Fried, A.; Huey, L. G.

    2012-12-01

    We are able to attribute sources of both radical reactivity and NO that determined the smog-chemical production rate of ozone, P(O3), for NASA's wide-ranging sampling of California air in June, 2008, part of the ARCTAS intensive. We relate formaldehyde, HCHO, and reactive nitrogen oxides, NOx, to a variety of distinct "marker" species that identify origins. We have labeled the sources and markers as (i) Fire emissions (CH3CN), (ii) Biogenic emissions (Isoprene), (iii) Urban/business emissions (CHCl3), (iv) Transport-related fuel consumption, (SO2), and (v) Refining/Port emissions ("residual" toluene). We use multiple linear regression with some appropriate restrictions. We achieve R-squared or explained variance of 88% for HCHO (VOC's) and 60% for NOx. HCHO and NOx are slowly evolving measures of potential ozone generation. The two related but radiation-influenced measures j (HCHO->H+HCO) x [HCHO] and [NO] quantitatively, but non-linearly, relate to instantaneous ozone production in California air, with R-squared of 86-93%, just as in New York City (Chatfield et al., Atmos. Environ., 2010). Maps of attribution for 650 samples from the Port of San Diego to the Northern Sierra foothills, and offshore -— all show huge variability in source attributions for VOCs and NOx. They indicate a widespread fire-emission influence on VOCs as they produce peroxy radicals, but show no positive influence on NOx, in fact consuming NOx from other sources. Comparisons with simulations help to refine our attribution classes and also to check balances of VOC emissions in available inventories. The use of the P(O3) measures is directly translatable to a method for estimate smog-ozone production rate from space, as data from another intensive, DISCOVER-AQ, show. (Left) A rare example where all sources contribute significantly, with markers and tentative attributions marked. (Right) Three different situations describing the control of smog ozone production, all from the same geographic

  11. Gravity's Smoking Gun?

    NASA Astrophysics Data System (ADS)

    Gaztañaga, Enrique; Juszkiewicz, Roman

    2001-09-01

    We present a new constraint on the biased galaxy formation picture. Gravitational instability theory predicts that the two-point mass density correlation function, ξ(r), has an inflection point at the separation r=r0, corresponding to the boundary between the linear and nonlinear regime of clustering, ξ~=1. We show how this feature can be used to constrain the biasing parameter b2≡ξg(r)/ξ(r) on scales r~=r0, where ξg is the galaxy-galaxy correlation function, which is allowed to differ from ξ. We apply our method to real data: the ξg(r), estimated from the Automatic Plate Measuring (APM) galaxy survey. Our results suggest that the APM galaxies trace the mass at separations r>~5 h-1 Mpc, where h is the Hubble constant in units of 100 km s-1 Mpc-1. The present results agree with earlier studies, based on comparing higher order correlations in the APM with weakly nonlinear perturbation theory. Both approaches constrain the b factor to be within 20% of unity. If the existence of the feature that we identified in the APM ξg(r)-the inflection point near ξg=1-is confirmed by more accurate surveys, we may have discovered gravity's smoking gun: the long-awaited ``shoulder'' in ξ, predicted by Gott and Rees 25 years ago.

  12. Radiocarbon ( 14C) measurements to quantify sources of atmospheric carbon monoxide in urban air

    NASA Astrophysics Data System (ADS)

    Klouda, George A.; Connolly, Michael V.

    Atmospheric air samples were collected during the winter of 1989-1990 in Albuquerque, NM, U.S.A., for radiocarbon ( 14C) analysis of carbon monoxide (CO). An experimental sample design was prepared to target periods when the concentration of CO exceeds the 9 μl l-1 (volume fraction), 8 h National Ambient Air Quality Standard (NAAQS) and during periods of attainment. Sampling sites, time of day, sampling duration, and meteorology were carefully considered so that source impacts be optimal. A balanced sampling factorial design was used to yield maximum information from the constraints imposed; the number of samples was limited by the number of sample canisters available, time and resources. Radiocarbon measurements of urban CO, " clean-air" CO background from Niwot Ridge, Colorado, average (wood) logs and oxygenated-gasolines were used in a three-source model to calculate the contribution of wood burning to the total atmospheric CO burden in Albuquerque. Results show that the estimated fractional contribution of residential wood combustion (Θ' Rwc) ranged from 0 to 0.30 of CO concentrations corrected for " clean-air" background. For these same samples, the respective CO concentrations attributed to wood burning range from 0 to 0.90 μmol mol -1 (mole fraction), well below the NAAQS. In all cases, fossil CO is the predominant source of ambient CO concentrations ranging from 0.96 to 6.34 μmol mol -1 A final comment is made on the potential of fossil CO measurements as an indirect tracer of atmospheric benzene, relevant to exposure risk estimates of motor vehicle emissions and occupational health and safety standards.

  13. Alternative methods of reducing air pollution from low-emissions sources in Krakow

    SciTech Connect

    Bieda, J.; Bardel, J.; Nedoma, J.; Pierce, B.

    1994-10-01

    A study on air quality monitoring carried out in the 1980s indicated that around 40% of the high concentrations of air pollutants adversely affecting residents and the natural environment were contributed by coal-fired home stoves and boiler houses using solid fuels. These heat sources discharging particulate matters at low heights, basically lacking any pollution control devices, are called the ``low emission sources.`` The American-Polish Program on Clean Fossil Fuels and Energy Efficiency in Krakow, which began in 1992, was preceded by a detailed inventory of low emissions sources completed in 1991. In the American-Polish program it has been accepted that all possible technical means would be used to reduce pollution, mainly those which enable utilization of reserves present in the existing networks of: district heating; gas distribution; and power distribution. The analysis indicated that the following activities can bring about realistic progress in reducing air pollution: elimination of the existing solid fuel boiler houses by connecting the buildings they serve to the municipal district heating network; elimination of solid fuel boiler houses by converting them to natural gas; elimination of solid fuel-fired home stoves by replacing them with electric heating; modernization of those solid fuel boiler houses which cannot by eliminated because of their function; and reducing the adverse environmental effects of home stove use throughout the city by changes in the combustion process, eliminating coal and replacing it with natural gas or electricity, and/or looking for combustion devices that can burn coal without producing air pollutants.

  14. Quantifying the effect of the air/water interface in marine active source EM

    NASA Astrophysics Data System (ADS)

    Wright, David

    2015-07-01

    The marine controlled source EM surveying method has become an accepted tool for deep water exploration for oil and gas reserves. In shallow water (< 500 m) data are complicated by the signal which interacts with the water-air interface which can dominate the response at the receiver. By decomposing the 1-D response to an impulsive current dipole source in the time domain and frequency domain I separate the response into: (1) an earth response, (2) a direct arrival, (3) a coupled airwave which travels through the air and (4) a surface coupling term which travels through the earth. The last two terms are coupled to the sea surface as well as to the earth resistivity structure but one travels through the air between source and receiver and the other only through the earth. Using a range of simple models I quantify the effect of these four terms in the time domain and the frequency domain. The results show that in shallow water the total response is significantly larger than in very deep water and that a large part of this extra energy comes from surface coupling, which is reflected at the sea surface and does not propagate through the air but through the earth. As a result, this term is highly sensitive to the resistivity of the earth. This means that the sea surface in shallow water not only significantly increases the signal strength of CSEM data but also enhances the sensitivity to subsurface resistivity structure. Compared with the surface coupling term, the coupled part of the airwave contains very little information about the earth, and is limited to the near surface. Time domain separation of the airwave from the surface coupling response results in greater sensitivity to a deep resistive target than frequency domain separation although there is also reasonable sensitivity in the frequency domain.

  15. 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

  16. [Suicide with home-made gun].

    PubMed

    Safr, M; Hejna, P; Zátopková, L

    2009-04-01

    Three cases of suicide by single bullet injury to head by home-made guns with immediate incapacitation are reported in following article. Zip gun (home-made gun) is a improvised firearm, usually a handgun. Home-made guns are almost always single-shot, as the improvised construction sometimes makes them weak enough to be destroyed by the act of firing. Zip guns are mostly smoothbore. Zip gun injuries, although unique today, represent a special category of missile injury with atypical low velocity terminal ballistics.

  17. Investigation and estimation of emission sources of 54 volatile organic compounds in ambient air in Tokyo

    NASA Astrophysics Data System (ADS)

    Hoshi, Jun-ya; Amano, Saeko; Sasaki, Yuko; Korenaga, Takashi

    Atmospheric concentrations of 52 hydrocarbons and two aldehydes at roadside and urban sites in Tokyo metropolitan area, Japan were analyzed using GC/MS and HPLC. Monthly sampling was conducted during April 2003-March 2005. Annual average concentrations of individual volatile organic compounds (VOCs) at the roadside site were 1.7-1.9 times higher than at the urban site, suggesting that vehicle exhausts strongly affect VOC concentrations. Since high temperatures and under the stagnant meteorological conditions might increase VOC concentrations in air, the levels of alkanes, alkenes, and aromatic hydrocarbons rose in summer and autumn in 2003 and 2004. The VOCs concentrations against benzene (VOCs/Bz) suggest classifying three groups of VOCs: those mainly from mobile emission sources, those mainly from stationary sources, and those comprising unstable compounds such as aldehydes and 1,3-butadiene. The VOC/Bz technique was applied to registered VOC data from the Pollutant Release and Transfer Register (PRTR). Results show that these VOCs in ambient air in Tokyo reflect the PRTR estimated release amounts. The VOC/Bz technique based on environmental monitoring data is useful to estimate non-registered VOCs such as butane and isopentane. Results show the possibility of estimating emission sources using VOC/Bz ratios from environmental monitoring data, even when sufficient information on the emission sources are not available.

  18. A fast pulsed power source applied to treatment of conducting liquids and air

    SciTech Connect

    Heesch, E.J.M. van; Pemen, A.J.M.; Huijbrechts, P.A.H.J.; Laan, P.C.T. van der; Ptasinski, K.J.; Zanstra, G.J.; Jong, P. de

    2000-02-01

    Two pilot pulsed power sources were developed for fundamental investigations and industrial demonstrations of treatment of conducting liquids. The developed heavy-duty power sources have an output voltage of 100 kV (rise time 10 ns, pulse duration 150 ns, pulse repetition rate maximum 1,000 pps). A pulse energy of 0.5--3 J/pulse and an average pulse power of 1.5 kW have been achieved with an efficiency of about 80%. In addition, adequate electromagnetic compatibility is achieved between the high-voltage pulse sources and the surrounding equipment. Various applications, such as the use of pulsed electric fields (PEF's) or pulsed corona discharges for inactivation of microorganisms in liquids or air, have been tested in the laboratory. For PEF treatment, homogeneous electric fields in the liquid of up to 70 kV/cm at a pulse repetition rate of 10--400 pps could be achieved. The inactivation is found to be 85 kJ/L per log reduction for Pseudomonas fluorescens and 500 kJ/L per log reduction for spores of Bacillus cereus. Corona directly applied to the liquid is found to be more efficient than PEF. With direct corona they achieve 25 kJ/L per log reduction for both Gram positive and Gram negative bacteria. For air disinfection using their corona pulse source, the measured efficiencies are excellent: 2 J/L per log reduction.

  19. C-PORT: A Community-Scale Near-Source Air Quality System to Assess Port-Related Air Quality Impacts

    EPA Science Inventory

    With increasing activity in global trade, there has been increased activity in transportation by rail, road and ships to move cargo. Based upon multiple near-road and near-source monitoring studies, both busy roadways and large emission source at the ports may impact local air qu...

  20. A novel electron gun for inline MRI-linac configurations

    PubMed Central

    Constantin, Dragoş E.; Holloway, Lois; Keall, Paul J.; Fahrig, Rebecca

    2014-01-01

    Purpose: This work introduces a new electron gun geometry capable of robust functioning in the presence of a high strength external magnetic field for axisymmetric magnetic resonance imaging (MRI)-linac configurations. This allows an inline MRI-linac to operate without the need to isolate the linear accelerator (linac) using a magnetic shield. This MRI-linac integration approach not only leaves the magnet homogeneity unchanged but also provides the linac flexibility to move along the magnet axis of symmetry if the source to target distance needs to be adjusted. Methods: Simple electron gun geometry modifications of a Varian 600C electron gun are considered and solved in the presence of an external magnetic field in order to determine a set of design principles for the new geometry. Based on these results, a new gun geometry is proposed and optimized in the fringe field of a 0.5 T open bore MRI magnet (GE Signa SP). A computer model for the 6 MeV Varian 600C linac is used to determine the capture efficiency of the new electron gun-linac system in the presence of the fringe field of the same MRI scanner. The behavior of the new electron gun plus the linac system is also studied in the fringe fields of two other magnets, a 1.0 T prototype open bore magnet and a 1.5 T GE Conquest scanner. Results: Simple geometrical modifications of the original electron gun geometry do not provide feasible solutions. However, these tests show that a smaller transverse cathode diameter with a flat surface and a slightly larger anode diameter could alleviate the current loss due to beam interactions with the anode in the presence of magnetic fields. Based on these findings, an initial geometry resembling a parallel plate capacitor with a hole in the anode is proposed. The optimization procedure finds a cathode-anode distance of 5 mm, a focusing electrode angle of 5°, and an anode drift tube length of 17.1 mm. Also, the linac can be displaced with ±15 cm along the axis of the 0.5 T

  1. A novel electron gun for inline MRI-linac configurations

    SciTech Connect

    Constantin, Dragoş E. Fahrig, Rebecca; Holloway, Lois; Keall, Paul J.

    2014-02-15

    Purpose: This work introduces a new electron gun geometry capable of robust functioning in the presence of a high strength external magnetic field for axisymmetric magnetic resonance imaging (MRI)-linac configurations. This allows an inline MRI-linac to operate without the need to isolate the linear accelerator (linac) using a magnetic shield. This MRI-linac integration approach not only leaves the magnet homogeneity unchanged but also provides the linac flexibility to move along the magnet axis of symmetry if the source to target distance needs to be adjusted. Methods: Simple electron gun geometry modifications of a Varian 600C electron gun are considered and solved in the presence of an external magnetic field in order to determine a set of design principles for the new geometry. Based on these results, a new gun geometry is proposed and optimized in the fringe field of a 0.5 T open bore MRI magnet (GE Signa SP). A computer model for the 6 MeV Varian 600C linac is used to determine the capture efficiency of the new electron gun-linac system in the presence of the fringe field of the same MRI scanner. The behavior of the new electron gun plus the linac system is also studied in the fringe fields of two other magnets, a 1.0 T prototype open bore magnet and a 1.5 T GE Conquest scanner. Results: Simple geometrical modifications of the original electron gun geometry do not provide feasible solutions. However, these tests show that a smaller transverse cathode diameter with a flat surface and a slightly larger anode diameter could alleviate the current loss due to beam interactions with the anode in the presence of magnetic fields. Based on these findings, an initial geometry resembling a parallel plate capacitor with a hole in the anode is proposed. The optimization procedure finds a cathode-anode distance of 5 mm, a focusing electrode angle of 5°, and an anode drift tube length of 17.1 mm. Also, the linac can be displaced with ±15 cm along the axis of the 0.5 T

  2. Long-Life/Low-Power Ion-Gun Cathode

    NASA Technical Reports Server (NTRS)

    Fitzgerald, D. J.

    1982-01-01

    New cathode has form of hollow tube through which gas enters region of high electron density, produced by electric discharge with auxiliary electrode referred to as "keeper." Ion-gun cathode emits electrons that bombard gas in chamber. Ions accelerated out of source are used to dope semiconductor material.

  3. The system of RF beam control for electron gun

    NASA Astrophysics Data System (ADS)

    Barnyakov, A. M.; Chernousov, Yu. D.; Ivannikov, V. I.; Levichev, A. E.; Shebolaev, I. V.

    2015-06-01

    The system of RF control of three-electrode electron gun current is described. It consists of a source of microwave signal, coaxial line, coaxial RF switch and RF antenna lead. The system allows one to get the electron beam in the form of bunches with the frequency of the accelerating section to achieve the capture of particles in the acceleration mode close to 100%. The results of calculation and analysis of the elements of the system are presented. Characteristics of the devices are obtained experimentally. The results of using RF control in three-electrode electron gun at electron linear accelerator are described.

  4. Development program on a Spindt cold-cathode electron gun

    NASA Technical Reports Server (NTRS)

    Spindt, C. A.

    1982-01-01

    A thin film field emission cathode (TFFEC) array and a cold cathode electron gun based on the emitter were developed. A microwave tube gun that uses the thin film field emission cathode as an electron source is produced. State-of-the-art cathodes were fabricated and tested. The tip-packing density of the arrays were increased thereby increasing the cathode's current density capability. The TFFEC is based on the well known field emission effect and was conceived to exploit the advantages of that phenomenon while minimizing the difficulties associated with conventional field emission structures, e.g. limited life and high voltage requirements. Field emission follows the Fowler-Nordheim equation.

  5. Entrainment Rate in Shallow Cumuli: Dependence on Entrained Dry Air Sources and Probability Density Functions

    NASA Astrophysics Data System (ADS)

    Lu, C.; Liu, Y.; Niu, S.; Vogelmann, A. M.

    2012-12-01

    In situ aircraft cumulus observations from the RACORO field campaign are used to estimate entrainment rate for individual clouds using a recently developed mixing fraction approach. The entrainment rate is computed based on the observed state of the cloud core and the state of the air that is laterally mixed into the cloud at its edge. The computed entrainment rate decreases when the air is entrained from increasing distance from the cloud core edge; this is because the air farther away from cloud edge is drier than the neighboring air that is within the humid shells around cumulus clouds. Probability density functions of entrainment rate are well fitted by lognormal distributions at different heights above cloud base for different dry air sources (i.e., different source distances from the cloud core edge). Such lognormal distribution functions are appropriate for inclusion into future entrainment rate parameterization in large scale models. To the authors' knowledge, this is the first time that probability density functions of entrainment rate have been obtained in shallow cumulus clouds based on in situ observations. The reason for the wide spread of entrainment rate is that the observed clouds are affected by entrainment mixing processes to different extents, which is verified by the relationships between the entrainment rate and cloud microphysics/dynamics. The entrainment rate is negatively correlated with liquid water content and cloud droplet number concentration due to the dilution and evaporation in entrainment mixing processes. The entrainment rate is positively correlated with relative dispersion (i.e., ratio of standard deviation to mean value) of liquid water content and droplet size distributions, consistent with the theoretical expectation that entrainment mixing processes are responsible for microphysics fluctuations and spectral broadening. The entrainment rate is negatively correlated with vertical velocity and dissipation rate because entrainment

  6. A framework for air quality monitoring based on free public data and open source tools

    NASA Astrophysics Data System (ADS)

    Nikolov, Hristo; Borisova, Denitsa

    2014-10-01

    In the recent years more and more widely accepted by the Space agencies (e.g. NASA, ESA) is the policy toward provision of Earth observation (EO) data and end products concerning air quality especially in large urban areas without cost to researchers and SMEs. Those EO data are complemented by increasing amount of in-situ data also provided at no cost either from national authorities or having crowdsourced origin. This accessibility together with the increased processing capabilities of the free and open source software is a prerequisite for creation of solid framework for air modeling in support of decision making at medium and large scale. Essential part of this framework is web-based GIS mapping tool responsible for dissemination of the output generated. In this research an attempt is made to establish a running framework based solely on openly accessible data on air quality and on set of freely available software tools for processing and modeling taking into account the present status quo in Bulgaria. Among the primary sources of data, especially for bigger urban areas, for different types of gases and dust particles, noted should be the National Institute of Meteorology and Hydrology of Bulgaria (NIMH) and National System for Environmental Monitoring managed by Bulgarian Executive Environmental Agency (ExEA). Both authorities provide data for concentration of several gases just to mention CO, CO2, NO2, SO2, and fine suspended dust (PM10, PM2.5) on monthly (for some data on daily) basis. In the framework proposed these data will complement the data from satellite-based sensors such as OMI instrument aboard EOS-Aura satellite and from TROPOMI instrument payload for future ESA Sentinel-5P mission. Integral part of the framework is the modern map for the land use/land cover which is provided from EEA by initiative GIO Land CORINE. This map is also a product from EO data distributed at European level. First and above all, our effort is focused on provision to the

  7. Air exposure of coral is a significant source of dimethylsulfide (DMS) to the atmosphere

    PubMed Central

    Hopkins, Frances E.; Bell, Thomas G.; Yang, Mingxi; Suggett, David J.; Steinke, Michael

    2016-01-01

    Corals are prolific producers of dimethylsulfoniopropionate (DMSP). High atmospheric concentrations of the DMSP breakdown product dimethylsulfide (DMS) have been linked to coral reefs during low tides. DMS is a potentially key sulfur source to the tropical atmosphere, but DMS emission from corals during tidal exposure is not well quantified. Here we show that gas phase DMS concentrations (DMSgas) increased by an order of magnitude when three Indo-Pacific corals were exposed to air in laboratory experiments. Upon re-submersion, an additional rapid rise in DMSgas was observed, reflecting increased production by the coral and/or dissolution of DMS-rich mucus formed by the coral during air exposure. Depletion in DMS following re-submersion was likely due to biologically-driven conversion of DMS to dimethylsulfoxide (DMSO). Fast Repetition Rate fluorometry showed downregulated photosynthesis during air exposure but rapid recovery upon re-submersion, suggesting that DMS enhances coral tolerance to oxidative stress during a process that can induce photoinhibition. We estimate that DMS emission from exposed coral reefs may be comparable in magnitude to emissions from other marine DMS hotspots. Coral DMS emission likely comprises a regular and significant source of sulfur to the tropical marine atmosphere, which is currently unrecognised in global DMS emission estimates and Earth System Models. PMID:27796323

  8. Nature of air pollution, emission sources, and management in the Indian cities

    NASA Astrophysics Data System (ADS)

    Guttikunda, Sarath K.; Goel, Rahul; Pant, Pallavi

    2014-10-01

    The global burden of disease study estimated 695,000 premature deaths in 2010 due to continued exposure to outdoor particulate matter and ozone pollution for India. By 2030, the expected growth in many of the sectors (industries, residential, transportation, power generation, and construction) will result in an increase in pollution related health impacts for most cities. The available information on urban air pollution, their sources, and the potential of various interventions to control pollution, should help us propose a cleaner path to 2030. In this paper, we present an overview of the emission sources and control options for better air quality in Indian cities, with a particular focus on interventions like urban public transportation facilities; travel demand management; emission regulations for power plants; clean technology for brick kilns; management of road dust; and waste management to control open waste burning. Also included is a broader discussion on key institutional measures, like public awareness and scientific studies, necessary for building an effective air quality management plan in Indian cities.

  9. Development of an Air-Source Heat Pump Integrated with a Water Heating / Dehumidification Module

    SciTech Connect

    Rice, C Keith; Uselton, Robert B.; Shen, Bo; Baxter, Van D; Shrestha, Som S

    2014-01-01

    A residential-sized dual air-source integrated heat pump (AS-IHP) concept is under development in partnership between ORNL and a manufacturer. The concept design consists of a two-stage air-source heat pump (ASHP) coupled on the air distribution side with a separate novel water heating/dehumidification (WH/DH) module. The motivation for this unusual equipment combination is the forecast trend for home sensible loads to be reduced more than latent loads. Integration of water heating with a space dehumidification cycle addresses humidity control while performing double-duty. This approach can be applied to retrofit/upgrade applications as well as new construction. A WH/DH module capable of ~1.47 L/h water removal and ~2 kW water heating capacity was assembled by the manufacturer. A heat pump system model was used to guide the controls design; lab testing was conducted and used to calibrate the models. Performance maps were generated and used in a TRNSYS sub-hourly simulation to predict annual performance in a well-insulated house. Annual HVAC/WH energy savings of ~35% are predicted in cold and hot-humid U.S. climates compared to a minimum efficiency baseline.

  10. Air Pollution in São Paulo and Santiago de Chile: Sources and Impacts

    NASA Astrophysics Data System (ADS)

    Artaxo, P.; Castanho, A.; Oyolla, P.; Gramsch, E.; Martinez, R.

    2007-05-01

    Urban air pollution is a serious issue for millions in Latin America. São Paulo, Santiago de Chile, México City and many other large urban conglomerates. Fast industrialization, large population growth, emissions from the transportation sectors and many other issues are the cause for the air pollution in these mega cities. São Paulo, with 17 million people, 5.5 million vehicles and strong industry suffers from severe particulate matter and ozone exposure. Santiago de Chile with very unfavorable dispersion characteristics also has problems with PM10 and ozone. Health effects in these areas are a public health concern. In Sao Paulo alone, about 30,000 excess deaths are attributable to air pollution issues. There are also critical institutional issues in the São Paulo metropolitan area, which has 39 municipalities, as well as three other metropolitan areas within a 100-km radius. In Santiago de Chile, a dry climate makes ressuspended soil dust an important PM10 component, and vehicle emissions produces high concentration of secondary organic aerosols. Old diesel buses make black carbon concentrations very high in Santiago. We carried out extensive aerosol source apportionment studies for several years, using PIXE as trace element analysis technique and multivariate statistical analysis to separate and quantify aerosol sources in Santiago and Sao Paulo. We will present results from 5 years studies in both Santiago and Sao Paulo. Vehicles and soil dust dominates the picture, with a strong sulfate component in Santiago de Chile.

  11. Forecasting daily source air quality using multivariate statistical analysis and radial basis function networks.

    PubMed

    Sun, Gang; Hoff, Steven J; Zelle, Brian C; Nelson, Minda A

    2008-12-01

    It is vital to forecast gas and particle matter concentrations and emission rates (GPCER) from livestock production facilities to assess the impact of airborne pollutants on human health, ecological environment, and global warming. Modeling source air quality is a complex process because of abundant nonlinear interactions between GPCER and other factors. The objective of this study was to introduce statistical methods and radial basis function (RBF) neural network to predict daily source air quality in Iowa swine deep-pit finishing buildings. The results show that four variables (outdoor and indoor temperature, animal units, and ventilation rates) were identified as relative important model inputs using statistical methods. It can be further demonstrated that only two factors, the environment factor and the animal factor, were capable of explaining more than 94% of the total variability after performing principal component analysis. The introduction of fewer uncorrelated variables to the neural network would result in the reduction of the model structure complexity, minimize computation cost, and eliminate model overfitting problems. The obtained results of RBF network prediction were in good agreement with the actual measurements, with values of the correlation coefficient between 0.741 and 0.995 and very low values of systemic performance indexes for all the models. The good results indicated the RBF network could be trained to model these highly nonlinear relationships. Thus, the RBF neural network technology combined with multivariate statistical methods is a promising tool for air pollutant emissions modeling.

  12. Sources and sinks of acetone, methanol, and acetaldehyde in North Atlantic marine air

    NASA Astrophysics Data System (ADS)

    Lewis, A. C.; Hopkins, J. R.; Carpenter, L. J.; Stanton, J.; Read, K. A.; Pilling, M. J.

    2005-08-01

    Measurements of acetone, methanol, acetaldehyde and a range of non-methane hydrocarbons have been made in North Atlantic marine air at the Mace Head observatory. Under maritime conditions the combination of OVOCs (acetone, methanol and acetaldehyde) contributed up to 85% of the total mass of measured non methane organics in air and up to 80% of the OH radical organic sink, when compared with the sum of all other organic compounds including non-methane hydrocarbons, DMS and OH-reactive halocarbons (trichloromethane and tetrachloroethylene). The observations showed anomalies in the variance and abundance of acetaldehyde and acetone over that expected for species with a remote terrestrial emission source and OH controlled chemical lifetime. A detailed model incorporating an explicit chemical degradation mechanism indicated in situ formation during air mass transport was on timescales longer than the atmospheric lifetime of precursor hydrocarbons or primary emission. The period over which this process was significant was similar to that of airmass motion on intercontinental scales, and formation via this route may reproduce that of a widespread diffuse source. The model indicates that continued short chain OVOC formation occurs many days from the point of emission, via longer lived intermediates of oxidation such as organic peroxides and long chain alcohols.

  13. Sources and sinks of acetone, methanol, and acetaldehyde in North Atlantic air

    NASA Astrophysics Data System (ADS)

    Lewis, A. C.; Hopkins, J. R.; Carpenter, L. J.; Stanton, J.; Read, K. A.; Pilling, M. J.

    2005-03-01

    Measurements of acetone, methanol, acetaldehyde and a range of non-methane hydrocarbons have been made in North Atlantic marine air at the Mace Head observatory. Under maritime conditions the combination of OVOCs (acetone, methanol and 5 acetaldehyde) contributed up to 85% of the total mass of measured non methane organics in air and up to 80% of the OH radical organic sink, when compared with the sum of all other organic compounds including non-methane hydrocarbons, DMS and OH-reactive halocarbons (trichloromethane and tetrachloroethylene). The observations showed anomalies in the variance and abundance of acetaldehyde and acetone 10 over that expected for species with a remote terrestrial emission source and OH controlled chemical lifetime. A detailed model incorporating an explicit chemical degradation mechanism indicated in situ formation during air mass transport was on timescales longer than the atmospheric lifetime of precursor hydrocarbons or primary emission. The period over which this process was significant was similar to that of airmass mo15 tion on intercontinental scales, and formation via this route may reproduce that of a widespread diffuse source. The model indicates that continued short chain OVOC formation occurs many days from the point of emission, via longer lived intermediates of oxidation such as organic peroxides and long chain alcohols.

  14. Field investigation source area ST58 old Quartermaster service station, Eielson Air Force Base, Alaska

    SciTech Connect

    Liikala, T.L.; Evans, J.C.

    1995-01-01

    Source area ST58 is the site of the old Quartermaster service station at Eielson Air Force Base, Alaska. The source area is one of several Source Evaluation Report sites being investigated by Pacific Northwest Laboratory for the US Air Force as candidates for no further remedial action, interim removal action, or a remedial investigation/feasibility study under a Federal Facilities Agreement. The purpose of this work was to characterize source area ST58 and excavate the most contaminated soils for use in composting treatability studies. A field investigation was conducted to determine the nature and extent of soil contamination. The field investigation entailed a records search; grid node location, surface geophysical, and soil gas surveys; and test pit soil sampling. Soil excavation followed based on the results of the field investigation. The site was backfilled with clean soil. Results from this work indicate close spatial correlation between screening instruments, used during the field investigation and soil excavation, and laboratory analyses. Gasoline was identified as the main subsurface contaminant based on the soil gas surveys and test pit soil sampling. A center of contamination was located near the northcentral portion of the source area, and a center was located in the northwestern comer. The contamination typically occurred near or below a former soil horizon probably as a result of surface spills and leaks from discontinuities and/or breaks in the underground piping. Piping locations were delineated during the surface geophysical surveys and corresponded very well to unscaled drawings of the site. The high subsurface concentrations of gasoline detected in the northwestern comer of the source area probably reflect ground-water contamination and/or possibly floating product.

  15. rf traveling-wave electron gun for photoinjectors

    NASA Astrophysics Data System (ADS)

    Schaer, Mattia; Citterio, Alessandro; Craievich, Paolo; Reiche, Sven; Stingelin, Lukas; Zennaro, Riccardo

    2016-07-01

    The design of a photoinjector, in particular that of the electron source, is of central importance for free electron laser (FEL) machines where a high beam brightness is required. In comparison to standard designs, an rf traveling-wave photocathode gun can provide a more rigid beam with a higher brightness and a shorter pulse. This is illustrated by applying a specific optimization procedure to the SwissFEL photoinjector, for which a brightness improvement up to a factor 3 could be achieved together with a double gun output energy compared to the reference setup foreseeing a state-of-the-art S-band rf standing-wave gun. The higher brightness is mainly given by a (at least) double peak current at the exit of the gun which brings benefits for both the beam dynamics in the linac and the efficiency of the FEL process. The gun design foresees an innovative coaxial rf coupling at both ends of the structure which allows a solenoid with integrated bucking coil to be placed around the cathode in order to provide the necessary focusing right after emission.

  16. The Hobart Time Ball and Time Gun: a Critical Review

    NASA Astrophysics Data System (ADS)

    Kinns, Roger

    2011-07-01

    Discussion at the Royal Society in Hobart in 1865 and acoustic experiments in 1868 led to a combined time ball and time gun service in Hobart from March 1875. Complaints from residents led to relocation of the gun a month later, but it was then fired from Queen's Battery in the Domain for half a century. The drop of the ball at Battery Point was always the master signal; the gun was fired when the ball was seen to drop. During the early years, private citizens in Hobart provided the time reference. From September 1886, an electric telegraph signal from Hobart Observatory was used to provide correct time to the ball operator, but signals were of questionable accuracy. During February 1910, the source of the telegraph signal was changed from Hobart Observatory to Melbourne Observatory, but the service was still unreliable and there was pressure to re-equip Hobart Observatory. Finally, automatic dropping of the time ball by telegraph from Melbourne was introduced in November 1910. The time ball service ended in February 1927. The time gun had probably ceased to operate by the end of 1923, but before that date there were sometimes long gaps in the time gun service, particularly on Sundays.

  17. One century of air deposition of hydrocarbons recorded in travertine in North Tibetan Plateau, China: Sources and evolution.

    PubMed

    Yuan, Guo-Li; Wu, Ming-Zhe; Sun, Yong; Li, Jun; Li, Jing-Chao; Wang, Gen-Hou

    2016-08-01

    The characteristic distribution patterns of hydrocarbons have been used for fingerprinting to identify their sources. The historical air depositions of hydrocarbons recorded in natural media help to understand the evolution of the air environment. Travertine is a natural acceptor of air deposition that settles on the ground layer by layer. To reconstruct the historical air environment of hydrocarbons in the North Tibetan Plateau (NTP), a unique background region, twenty-seven travertine samples were collected systematically from a travertine column according to its precipitated year. For each sample, the precipitated year was dated while n-alkanes and polycyclic aromatic hydrocarbons (PAHs) were determined. Based on source identification, the air environment of hydrocarbons in the past century was studied for the region of NTP. Before World War II, the anthropogenic sources of hydrocarbons showed little influence on the air environment. During World War II and China's War of Liberation, hydrocarbons increased significantly, mainly from the use of fossil fuels. Between 1954 and 1963, hydrocarbons in the air decreased significantly because the sources of petroleum combustion decreased. From the mid-1960s through the end of the 1990s, air hydrocarbons, which mainly originated from biomass burning, increased gradually because agriculture and animal husbandry were developing steadily in Tibet and China. From the late 1990s, hydrocarbons in the atmosphere increased rapidly due to the rapid increase of tourism activities, which might increase hydrocarbon emissions from traffic. The reconstruction of the historical air hydrocarbons in NTP clearly reflects the evolution of the region and global development.

  18. Development of a Mobile Tracer Correlation Techniques for Assessment of Air Emissions from Landfills and Other Area Sources

    EPA Science Inventory

    Improved understanding of air emissions from large area sources such as landfills, waste water ponds, open-source processing, and agricultural operations is a topic of increasing environmental importance. In many cases, the size of the area source, coupled with spatial-heteroge...

  19. Source apportionment of size resolved particulate matter at a European air pollution hot spot.

    PubMed

    Pokorná, P; Hovorka, J; Klán, M; Hopke, P K

    2015-01-01

    Positive Matrix Factorization-PMF was applied to hourly resolved elemental composition of fine (PM0.15-1.15) and coarse (PM1.15-10) aerosol particles to apportion their sources in the airshed of residential district, Ostrava-Radvanice and Bartovice in winter 2012. Multiple-site measurement by PM2.5 monitors complements the source apportionment. As there were no statistical significant differences amongst the monitors, the source apportionment derived for the central site data is expected to apply to whole residential district. The apportioned sources of the fine aerosol particles were coal combustion (58.6%), sinter production-hot phase (22.9%), traffic (15%), raw iron production (3.5%), and desulfurization slag processing (<0.5%) whilst road dust (47.3%), sinter production-cold phase (27.7%), coal combustion (16.8%), and raw iron production (8.2%) were resolved being sources of the coarse aerosol particles. The shape and elemental composition of size-segregated aerosol airborne-sampled by an airship aloft presumed air pollution sources helped to interpret the PMF solution. PMID:25260163

  20. [The chemical action of gun powder gases on biological tissues in a point-blank shot].

    PubMed

    Popov, V L; Isakov, V D; Babakhanian, R V; Karnasevich, Iu A

    1992-01-01

    Chemical effect of gun powder gas on the biologic tissues manifests by red-brown staining of the tissues, mainly at the expense of methemoglobin and sulfhemoglobin. Scarlet staining of the tissues at the edges of gun-shot wounds is not a specific marker of a shot made from a short distance; it may emerge several hours after wounding at the expense of hydroxy-hemoglobin and is not at all related to the chemical effect of gun powder gas. The conditions conducive to scarlet staining are an open wound permitting free oxygenation by air oxygen and hemoglobin transfer from the injured red cells into blood plasma and adjacent tissues.

  1. Polychlorinated naphthalenes in the air over the equatorial Indian Ocean: Occurrence, potential sources, and toxicity.

    PubMed

    Huang, Yumei; Li, Jun; Xu, Yue; Xu, Weihai; Zhong, Guangcai; Liu, Xiang; Zhang, Gan

    2016-06-15

    Monitoring of marine polychlorinated naphthalenes (PCNs) is crucial, as they are considered persistent organic pollutants (POPs) by the Stockholm Convention. Data on PCNs in marine environment are scarce. In this study, 19 air samples were collected during a cruise in the equatorial Indian Ocean on board the Chinese research vessel Shiyan I from 4/2011 to 5/2011. PCN concentration of these air samples ranged from 0.033 to 2.56pgm(-3), with an average of 0.518pgm(-3), equal to or lower than the values reported for other oceans, seas, and lakes worldwide. Tri- and tetra-CNs were the main homologues in most samples. Reemission of Halowax mixtures and incineration processes were the major sources of atmospheric PCNs in the study area. The PCN-corresponding toxic equivalency values ranged from 0 to 0.190fgm(-3) (average: 0.038fgm(-3)), falling in the low end of global range.

  2. The sources and fate of (210)Po in the urban air: A review.

    PubMed

    Długosz-Lisiecka, Magdalena

    2016-09-01

    The origin of (210)Po activity and its fluctuations in the air are discussed in this paper. In the case of atmospheric aerosol samples, a comparison of the (210)Po/(210)Pb and (210)Bi/(210)Pb activity ratios makes it possible not only to determine aerosol residence times but also to appraise the contribution of the unsupported (210)Po coming from other sources than (222)Rn decay, such as human industrial activities, especially coal combustion. A simple mathematical method makes it possible to observe the seasonal fluctuations of the anthropogenic excess of (210)Po in the urban air. The average doses of (210)Po intake with food (including drinking water) and inhalation of urban aerosols are usually lower than those from (210)Po intake by cigarette smokers and negligible in comparison to total natural radiation exposure. PMID:27295049

  3. Source apportionment and air quality impact assessment studies in Beijing/China

    NASA Astrophysics Data System (ADS)

    Suppan, P.; Schrader, S.; Shen, R.; Ling, H.; Schäfer, K.; Norra, S.; Vogel, B.; Wang, Y.

    2012-04-01

    More than 15 million people in the greater area of Beijing are still suffering from severe air pollution levels caused by sources within the city itself but also from external impacts like severe dust storms and long range advection from the southern and central part of China. Within this context particulate matter (PM) is the major air pollutant in the greater area of Beijing (Garland et al., 2009). PM did not serve only as lead substance for air quality levels and therefore for adverse health impact effects but also for a strong influence on the climate system by changing e.g. the radiative balance. Investigations on emission reductions during the Olympic Summer Games in 2008 have caused a strong reduction on coarser particles (PM10) but not on smaller particles (PM2.5). In order to discriminate the composition of the particulate matter levels, the different behavior of coarser and smaller particles investigations on source attribution, particle characteristics and external impacts on the PM levels of the city of Beijing by measurements and modeling are performed: Examples of long term measurements of PM2.5 filter sampling in 2005 with the objectives of detailed chemical (source attribution, carbon fraction, organic speciation and inorganic composition) and isotopic analyses as well as toxicological assessment in cooperation with several institutions (Karlsruhe Institute of Technology (IfGG/IMG), Helmholtz Zentrum München (HMGU), University Rostock (UR), Chinese University of Mining and Technology Beijing, CUMTB) will be discussed. Further experimental studies include the operation of remote sensing systems to determine continuously the MLH (by a ceilometer) and gaseous air pollutants near the ground (by DOAS systems) as well as at the 320 m measurement tower (adhesive plates at different heights for passive particle collection) in cooperation with the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences (CAS). The influence of the MLH on

  4. The contribution of outdoor air pollution sources to premature mortality on a global scale

    NASA Astrophysics Data System (ADS)

    Lelieveld, J.; Evans, J. S.; Fnais, M.; Giannadaki, D.; Pozzer, A.

    2015-09-01

    Assessment of the global burden of disease is based on epidemiological cohort studies that connect premature mortality to a wide range of causes, including the long-term health impacts of ozone and fine particulate matter with a diameter smaller than 2.5 micrometres (PM2.5). It has proved difficult to quantify premature mortality related to air pollution, notably in regions where air quality is not monitored, and also because the toxicity of particles from various sources may vary. Here we use a global atmospheric chemistry model to investigate the link between premature mortality and seven emission source categories in urban and rural environments. In accord with the global burden of disease for 2010 (ref. 5), we calculate that outdoor air pollution, mostly by PM2.5, leads to 3.3 (95 per cent confidence interval 1.61-4.81) million premature deaths per year worldwide, predominantly in Asia. We primarily assume that all particles are equally toxic, but also include a sensitivity study that accounts for differential toxicity. We find that emissions from residential energy use such as heating and cooking, prevalent in India and China, have the largest impact on premature mortality globally, being even more dominant if carbonaceous particles are assumed to be most toxic. Whereas in much of the USA and in a few other countries emissions from traffic and power generation are important, in eastern USA, Europe, Russia and East Asia agricultural emissions make the largest relative contribution to PM2.5, with the estimate of overall health impact depending on assumptions regarding particle toxicity. Model projections based on a business-as-usual emission scenario indicate that the contribution of outdoor air pollution to premature mortality could double by 2050.

  5. The contribution of outdoor air pollution sources to premature mortality on a global scale.

    PubMed

    Lelieveld, J; Evans, J S; Fnais, M; Giannadaki, D; Pozzer, A

    2015-09-17

    Assessment of the global burden of disease is based on epidemiological cohort studies that connect premature mortality to a wide range of causes, including the long-term health impacts of ozone and fine particulate matter with a diameter smaller than 2.5 micrometres (PM2.5). It has proved difficult to quantify premature mortality related to air pollution, notably in regions where air quality is not monitored, and also because the toxicity of particles from various sources may vary. Here we use a global atmospheric chemistry model to investigate the link between premature mortality and seven emission source categories in urban and rural environments. In accord with the global burden of disease for 2010 (ref. 5), we calculate that outdoor air pollution, mostly by PM2.5, leads to 3.3 (95 per cent confidence interval 1.61-4.81) million premature deaths per year worldwide, predominantly in Asia. We primarily assume that all particles are equally toxic, but also include a sensitivity study that accounts for differential toxicity. We find that emissions from residential energy use such as heating and cooking, prevalent in India and China, have the largest impact on premature mortality globally, being even more dominant if carbonaceous particles are assumed to be most toxic. Whereas in much of the USA and in a few other countries emissions from traffic and power generation are important, in eastern USA, Europe, Russia and East Asia agricultural emissions make the largest relative contribution to PM2.5, with the estimate of overall health impact depending on assumptions regarding particle toxicity. Model projections based on a business-as-usual emission scenario indicate that the contribution of outdoor air pollution to premature mortality could double by 2050.

  6. [Metabolic characteristics of air microbial communities from sandstorm source areas of the Taklamakan desert].

    PubMed

    Duan, Wei-Wei; Lou, Kai; Zeng, Jun; Hu, Rong; Shi, Ying-Wu; He, Qing; Liu, Xin-Chun; Sun, Jian; Chao, Qun-Fang

    2012-01-01

    The aim was to compare the characteristics and the differences in carbon catabolic diversity of air samples collected from five locations that around the edge of Taklamakan desert. The characteristics and the differences of carbon metabolic profiles were detected by using the BIOLOG micro plate (BIOLOG EcoPlate). The results showed that the average well color development (AWCD) curve of all five samples did not reach clear saturation during the incubation time (10 days), but differences among them were significant. The highest AWCD value appeared in Shache and the lowest was in Hotan, which were 0.24 and 0.1, respectively. Carbon utilization showed that all samples exhibited high level of polymer, carbohydrates, amino acids and carboxylic acid; however, amine and the phenol compound were the lowest. Principal components analysis (PCA) indicated that twenty categories of carbon significantly related to PC1 and twelve categories for PC2. Hierarchical cluster analysis showed these five areas could be divided into 2 clusters: (1) Hotan, Pishan, (2) Shache, Luntai, Ulugqat. Canonical correspondence analysis (CCA) showed that those community functional diversities were highly affected by some environmental factors, such as wind speed, altitude, humidity. Further investigation by correlation analysis revealed that the microbial communities using single carbon source were significantly affected by abiotic factors, such as the utilization of beta-methyl-D-glucoside, D-galacturonic acid and putrescine had significantly positive correlation (P < 0.05) with latitude; 2-hydroxy benzoic acid and alpha-D-lactose significantly related to wind speed (P < 0.05); and D-glucosaminic acid was positive with air pressure, but it negatively correlated with altitude (P < 0.05). In conclusion,the carbon sources provided by BIOLOG EcoPlate were utilized slowly by air microbial communities; and the characteristics of the air community carbon catabolic along the edge of the Taklamakan desert

  7. The contribution of outdoor air pollution sources to premature mortality on a global scale.

    PubMed

    Lelieveld, J; Evans, J S; Fnais, M; Giannadaki, D; Pozzer, A

    2015-09-17

    Assessment of the global burden of disease is based on epidemiological cohort studies that connect premature mortality to a wide range of causes, including the long-term health impacts of ozone and fine particulate matter with a diameter smaller than 2.5 micrometres (PM2.5). It has proved difficult to quantify premature mortality related to air pollution, notably in regions where air quality is not monitored, and also because the toxicity of particles from various sources may vary. Here we use a global atmospheric chemistry model to investigate the link between premature mortality and seven emission source categories in urban and rural environments. In accord with the global burden of disease for 2010 (ref. 5), we calculate that outdoor air pollution, mostly by PM2.5, leads to 3.3 (95 per cent confidence interval 1.61-4.81) million premature deaths per year worldwide, predominantly in Asia. We primarily assume that all particles are equally toxic, but also include a sensitivity study that accounts for differential toxicity. We find that emissions from residential energy use such as heating and cooking, prevalent in India and China, have the largest impact on premature mortality globally, being even more dominant if carbonaceous particles are assumed to be most toxic. Whereas in much of the USA and in a few other countries emissions from traffic and power generation are important, in eastern USA, Europe, Russia and East Asia agricultural emissions make the largest relative contribution to PM2.5, with the estimate of overall health impact depending on assumptions regarding particle toxicity. Model projections based on a business-as-usual emission scenario indicate that the contribution of outdoor air pollution to premature mortality could double by 2050. PMID:26381985

  8. [Metabolic characteristics of air microbial communities from sandstorm source areas of the Taklamakan desert].

    PubMed

    Duan, Wei-Wei; Lou, Kai; Zeng, Jun; Hu, Rong; Shi, Ying-Wu; He, Qing; Liu, Xin-Chun; Sun, Jian; Chao, Qun-Fang

    2012-01-01

    The aim was to compare the characteristics and the differences in carbon catabolic diversity of air samples collected from five locations that around the edge of Taklamakan desert. The characteristics and the differences of carbon metabolic profiles were detected by using the BIOLOG micro plate (BIOLOG EcoPlate). The results showed that the average well color development (AWCD) curve of all five samples did not reach clear saturation during the incubation time (10 days), but differences among them were significant. The highest AWCD value appeared in Shache and the lowest was in Hotan, which were 0.24 and 0.1, respectively. Carbon utilization showed that all samples exhibited high level of polymer, carbohydrates, amino acids and carboxylic acid; however, amine and the phenol compound were the lowest. Principal components analysis (PCA) indicated that twenty categories of carbon significantly related to PC1 and twelve categories for PC2. Hierarchical cluster analysis showed these five areas could be divided into 2 clusters: (1) Hotan, Pishan, (2) Shache, Luntai, Ulugqat. Canonical correspondence analysis (CCA) showed that those community functional diversities were highly affected by some environmental factors, such as wind speed, altitude, humidity. Further investigation by correlation analysis revealed that the microbial communities using single carbon source were significantly affected by abiotic factors, such as the utilization of beta-methyl-D-glucoside, D-galacturonic acid and putrescine had significantly positive correlation (P < 0.05) with latitude; 2-hydroxy benzoic acid and alpha-D-lactose significantly related to wind speed (P < 0.05); and D-glucosaminic acid was positive with air pressure, but it negatively correlated with altitude (P < 0.05). In conclusion,the carbon sources provided by BIOLOG EcoPlate were utilized slowly by air microbial communities; and the characteristics of the air community carbon catabolic along the edge of the Taklamakan desert

  9. Characterization and control of organic compounds emitted from air pollution sources. Final report

    SciTech Connect

    Schauer, J.J.; Kleeman, M.J.; Cass, G.R.; Simoneit, B.R.T.

    1998-04-01

    A dilution source sampling system is used to quantify the air pollutant emissions from major urban air pollution sources. The emissions from catalyst-equipped gasoline powered-motor vehicles, noncatalyst gasoline-powered motor vehicls, diesel trucks, meat charbroiling, the cooking of vegetables with seed oils, fireplace combustion of softwood and hardwood, cigarette combustion, and paint spray coating operations are characterized. Semi-volatile and particle-phase organic compounds in the diluted source emissions are collected simultaneously by both a traditional filter/PUF (polyurethane foam) sampling train and by an advanced organic compound-based denuder/filter/PUF sampling train to provide information on the gas/particle phase distribution of the semi-volatile organic compounds. Emission rates of hundreds of organic compounds, spanning carbon number from C1 to C29 are determined by gas chromatography/mass spectrometry and gas chromatography with flame ionization detection. Fine partile mass emission rates and fine particle elemental chemical composition are measured as well.

  10. Analytical dispersion model for the chain of primary and secondary air pollutants released from point source

    NASA Astrophysics Data System (ADS)

    Juodis, Laurynas; Filistovič, Vitold; Maceika, Evaldas; Remeikis, Vidmantas

    2016-03-01

    An analytical model for dispersion of air pollutants released from a point source forming a secondary pollutant (e.g. chemical transformation or parent-daughter radionuclide chain) is formulated considering the constant wind speed and eddy diffusivities as an explicit function of downwind distance from the source in Cauchy (reflection-deposition type) boundary conditions. The dispersion of pollutants has been investigated by using the Gaussian plume dispersion parameters σy and σz instead of the diffusivity parameters Ky and Kz. For primary pollutant it was proposed to use the derived dry deposition factor instead of the source depletion alternative. An analytical solution for steady-state two-dimensional pollutant transport in the atmosphere is presented. Derived formulas include dependency from effective release height, gravitational and dry deposition velocities of primary and secondary pollutants, advection, surface roughness length and empirical dispersion parameters σy and σz. Demonstration of analytical solution application is provided by calculation of 135Xe and 135C air activity concentrations and the applicability of the model for the solution of atmospheric pollution transport problems.

  11. Nanotip electron gun for the scanning electron microscope.

    PubMed

    Vladár, András E; Radi, Zsolt; Postek, Michael T; Joy, David C

    2006-01-01

    Experimental nanotips have shown significant improvement in the resolution performance of a cold field emission scanning electron microscope (SEM). Nanotip electron sources are very sharp electron emitter tips used as a replacement for the conventional tungsten field emission (FE) electron sources. Nanotips offer higher brightness and smaller electron source size. An electron microscope equipped with a nanotip electron gun can provide images with higher spatial resolution and with better signal-to-noise ratio. This could present a considerable advantage over the current SEM electron gun technology if the tips are sufficiently long-lasting and stable for practical use. In this study, an older field-emission critical dimension (CD) SEM was used as an experimental test platform. Substitution of tungsten nanotips for the regular cathodes required modification of the electron gun circuitry and preparation of nanotips that properly fit the electron gun assembly. In addition, this work contains the results of the modeling and theoretical calculation of the electron gun performance for regular and nanotips, the preparation of the SEM including the design and assembly of a measuring system for essential instrument parameters, design and modification of the electron gun control electronics, development of a procedure for tip exchange, and tests of regular emitter, sharp emitter and nanotips. Nanotip fabrication and characterization procedures were also developed. Using a "sharp" tip as an intermediate to the nanotip clearly demonstrated an improvement in the performance of the test SEM. This and the results of the theoretical assessment gave support for the installation of the nanotips as the next step and pointed to potentially even better performance. Images taken with experimental nanotips showed a minimum two-fold improvement in resolution performance than the specification of the test SEM. The stability of the nanotip electron gun was excellent; the tip stayed useful

  12. Aldehydes in relation to air pollution sources: A case study around the Beijing Olympics

    NASA Astrophysics Data System (ADS)

    Altemose, Brent; Gong, Jicheng; Zhu, Tong; Hu, Min; Zhang, Liwen; Cheng, Hong; Zhang, Lin; Tong, Jian; Kipen, Howard M.; Ohman-Strickland, Pamela; Meng, Qingyu; Robson, Mark G.; Zhang, Junfeng

    2015-05-01

    This study was carried out to characterize three aldehydes of health concern (formaldehyde, acetaldehyde, and acrolein) at a central Beijing site in the summer and early fall of 2008 (from June to October). Aldehydes in polluted atmospheres come from both primary and secondary sources, which limits the control strategies for these reactive compounds. Measurements were made before, during, and after the Beijing Olympics to examine whether the dramatic air pollution control measures implemented during the Olympics had an impact on concentrations of the three aldehydes and their underlying primary and secondary sources. Average concentrations of formaldehyde, acetaldehyde and acrolein were 29.3 ± 15.1 μg/m3, 27.1 ± 15.7 μg/m3 and 2.3 ± 1.0 μg/m3, respectively, for the entire period of measurements, all being at the high end of concentration ranges measured in cities around the world in photochemical smog seasons. Formaldehyde and acrolein increased during the pollution control period compared to the pre-Olympic Games, followed the changing pattern of temperature, and were significantly correlated with ozone and with a secondary formation factor identified by principal component analysis (PCA). In contrast, acetaldehyde had a reduction in mean concentration during the Olympic air pollution control period compared to the pre-Olympic period and was significantly correlated with several pollutants emitted from local emission sources (e.g., NO2, CO, and PM2.5). Acetaldehyde was also more strongly associated with primary emission sources including vegetative burning and oil combustion factors identified through the PCA. All three aldehydes were lower during the post-Olympic sampling period compared to the before and during Olympic periods, likely due to seasonal and regional effects. Our findings point to the complexity of source control strategies for secondary pollutants.

  13. Impact of HONO sources on the performance of mesoscale air quality models

    NASA Astrophysics Data System (ADS)

    Gonçalves, M.; Dabdub, D.; Chang, W. L.; Jorba, O.; Baldasano, J. M.

    2012-07-01

    Nitrous acid (HONO) photolysis constitutes a primary source of OH in the early morning, which leads to changes in model gas-phase and particulate matter concentrations. However, state-of-the-art models of chemical mechanisms share a common representation of gas-phase chemistry leading to HONO that fails in reproducing the observed profiles. Hence, there is a growing interest in improving the definition of additional HONO sources within air quality models, i.e. direct emissions or heterogeneous reactions. In order to test their feasibility under atmospheric conditions, the WRF-ARW/HERMES/CMAQ modeling system is applied with high horizontal resolution (4 × 4 km2) to Spain for November 24-27, 2008. HONO modeled sources include: (1) direct emissions from on-road transport; NO2 hydrolysis on aerosol and ground surfaces, the latter with (2) kinetics depending exclusively on available surfaces for reaction and (3) refined kinetics considering also relative humidity dependence; and (4) photoenhanced NO2 reduction on ground surfaces. The DOMINO measurement campaign performed in El Arenosillo (Southern Spain) provides valuable HONO observations. Modeled HONO results are consistently below observations, even when the most effective scenario is assessed, corresponding to contributions of direct emissions and NO2 hydrolysis with the simplest kinetics parameterization. With the additional sources of HONO, PM2.5 predictions can be up to 14% larger in urban areas. Quantified impacts on secondary pollutants have to be taken as a low threshold, due to the proven underestimation of HONO levels. It is fundamental to improve HONO sources definition within air quality models, both for the scientific community and decision makers.

  14. Aldehydes in Relation to Air Pollution Sources: A Case Study around the Beijing Olympics

    PubMed Central

    Altemose, Brent; Gong, Jicheng; Zhu, Tong; Hu, Min; Zhang, Liwen; Cheng, Hong; Zhang, Lin; Tong, Jian; Kipen, Howard M.; Strickland, Pamela Ohman; Meng, Qingyu; Robson, Mark G.; Zhang, Junfeng

    2015-01-01

    This study was carried out to characterize three aldehydes of health concern (formaldehyde, acetaldehyde, and acrolein) at a central Beijing site in the summer and early fall of 2008 (from June to October). Aldehydes in polluted atmospheres come from both primary and secondary sources, which limits the control strategies for these reactive compounds. Measurements were made before, during, and after the Beijing Olympics to examine whether the dramatic air pollution control measures implemented during the Olympics had an impact on concentrations of the three aldehydes and their underlying primary and secondary sources. Average concentrations of formaldehyde, acetaldehyde and acrolein were 29.3±15.1 μg/m3, 27.1±15.7 μg/m3 and 2.3±1.0 μg/m3, respectively, for the entire period of measurements, all being at the high end of concentration ranges measured in cities around the world in photochemical smog seasons. Formaldehyde and acrolein increased during the pollution control period compared to the pre-Olympic Games, followed the changing pattern of temperature, and were significantly correlated with ozone and with a secondary formation factor identified by principal component analysis (PCA). In contrast, acetaldehyde had a reduction in mean concentration during the Olympic air pollution control period compared to the pre-Olympic period and was significantly correlated with several pollutants emitted from local emission sources (e.g., NO2, CO, and PM2.5). Acetaldehyde was also more strongly associated with primary emission sources including vegetative burning and oil combustion factors identified through the PCA. All three aldehydes were lower during the post-Olympic sampling period compared to the before and during Olympic periods, likely due to seasonal and regional effects. Our findings point to the complexity of source control strategies for secondary pollutants. PMID:25883528

  15. Assessment of exposure to indoor air contaminants from combustion sources: methodology and application.

    PubMed

    Leaderer, B P; Zagraniski, R T; Berwick, M; Stolwijk, J A

    1986-08-01

    A methodology for assessing indoor air pollutant exposures is presented, with specific application to unvented combustion by-products. This paper describes the method as applied to a study of acute respiratory illness associated with the use of unvented kerosene space heaters in 333 residences in the New Haven, Connecticut, area from September 1982 to April 1983. The protocol serves as a prototype for a nested design of exposure assessment which could be applied to large-scale field studies of indoor air contaminant levels. Questionnaires, secondary records, and several methods of air monitoring offer a reliable method of estimating environmental exposures for assessing associations with health effects at a reasonable cost. Indoor to outdoor ratios of NO2 concentrations were found to be 0.58 +/- 0.31 for residences without known sources of NO2. Levels of NO2 were found to be comparable for homes with a kerosene heater only and those with a gas cooking stove only. Homes with a kerosene heater and a gas stove had average two-week NO2 levels approximately double those with only one source. Presence of tobacco smokers had a small but significant impact on indoor NO2 levels. Two-week average levels of indoor NO2 were found to be excellent predictors of total personal NO2 exposure for a small sample of adults. Residences with kerosene space heaters had SO2 levels corresponding to the number of hours of heater use and the sulfur content of the fuel. Formaldehyde levels were found to be low and not related to unvented combustion sources. NO2, SO2, and CO2 levels measured in some of the residences were found to exceed those levels specified in current national health standards.

  16. Automatic targeting of plasma spray gun

    DOEpatents

    Abbatiello, Leonard A.; Neal, Richard E.

    1978-01-01

    A means for monitoring the material portion in the flame of a plasma spray gun during spraying operations is provided. A collimated detector, sensitive to certain wavelengths of light emission, is used to locate the centroid of the material with each pass of the gun. The response from the detector is then relayed to the gun controller to be used to automatically realign the gun.

  17. Space-based detection of missing sulfur dioxide sources of global air pollution

    NASA Astrophysics Data System (ADS)

    McLinden, Chris A.; Fioletov, Vitali; Shephard, Mark W.; Krotkov, Nick; Li, Can; Martin, Randall V.; Moran, Michael D.; Joiner, Joanna

    2016-07-01

    Sulfur dioxide is designated a criteria air contaminant (or equivalent) by virtually all developed nations. When released into the atmosphere, sulfur dioxide forms sulfuric acid and fine particulate matter, secondary pollutants that have significant adverse effects on human health, the environment and the economy. The conventional, bottom-up emissions inventories used to assess impacts, however, are often incomplete or outdated, particularly for developing nations that lack comprehensive emission reporting requirements and infrastructure. Here we present a satellite-based, global emission inventory for SO2 that is derived through a simultaneous detection, mapping and emission-quantifying procedure, and thereby independent of conventional information sources. We find that of the 500 or so large sources in our inventory, nearly 40 are not captured in leading conventional inventories. These missing sources are scattered throughout the developing world--over a third are clustered around the Persian Gulf--and add up to 7 to 14 Tg of SO2 yr-1, or roughly 6-12% of the global anthropogenic source. Our estimates of national total emissions are generally in line with conventional numbers, but for some regions, and for SO2 emissions from volcanoes, discrepancies can be as large as a factor of three or more. We anticipate that our inventory will help eliminate gaps in bottom-up inventories, independent of geopolitical borders and source types.

  18. Space-Based Detection of Missing Sulfur Dioxide Sources of Global Air Pollution

    NASA Technical Reports Server (NTRS)

    McLinden, Chris A.; Fioletov, Vitali; Shephard, Mark W.; Krotkov, Nick; Li, Can; Martin, Randall V.; Moran, Michael D.; Joiner, Joanna

    2016-01-01

    Sulfur dioxide is designated a criteria air contaminant (or equivalent) by virtually all developed nations. When released into the atmosphere, sulfur dioxide forms sulfuric acid and fine particulate matter, secondary pollutants that have significant adverse effects on human health, the environment and the economy. The conventional, bottom-up emissions inventories used to assess impacts, however, are often incomplete or outdated, particularly for developing nations that lack comprehensive emission reporting requirements and infrastructure. Here we present a satellite-based, global emission inventory for SO2 that is derived through a simultaneous detection, mapping and emission-quantifying procedure, and thereby independent of conventional information sources. We find that of the 500 or so large sources in our inventory, nearly 40 are not captured in leading conventional inventories. These missing sources are scattered throughout the developing world-over a third are clustered around the Persian Gulf-and add up to 7 to 14 Tg of SO2 yr(exp -1), or roughly 6-12% of the global anthropogenic source. Our estimates of national total emissions are generally in line with conventional numbers, but for some regions, and for SO2 emissions from volcanoes, discrepancies can be as large as a factor of three or more. We anticipate that our inventory will help eliminate gaps in bottom-up inventories, independent of geopolitical borders and source types.

  19. An Autosampler and Field Sample Carrier for Maximizing Throughput Using an Open-Air, Surface Sampling Ion Source for MS

    EPA Science Inventory

    A recently developed, commercially available, open-air, surface sampling ion source for mass spectrometers provides individual analyses in several seconds. To realize its full throughput potential, an autosampler and field sample carrier were designed and built. The autosampler ...

  20. IN VIVO EVIDENCE OF FREE RADICAL FORMATION IN THE RAT LUNG AFTER EXPOSURE TO AN EMISSION SOURCE AIR POLLUTION PARTICLE

    EPA Science Inventory

    Exposure to air pollution particles can be associated with increased human morbidity and mortality. The mechanism(s) of lung injury remains unknown. We tested the hypothesis that lung exposure to oil fly ash (an emission source air pollution particle) causes in vivo free radical ...

  1. Assessment of Near-Source Air Pollution at a Fine Spatial Scale Utilizing a Mobile Monitoring Approach

    EPA Science Inventory

    Mobile monitoring is an emerging strategy to characterize spatially and temporally variable air pollution in areas near sources. EPA’s Geospatial Monitoring of Air Pollution (GMAP) vehicle – an all-electric vehicle measuring real-time concentrations of particulate and gaseous po...

  2. Assessment of near-source air pollution at a fine spatial scale utilizing a mobile measurement platform approach

    EPA Science Inventory

    Mobile monitoring is an emerging strategy to characterize spatially and temporally variable air pollution in areas near sources. EPA’s Geospatial Monitoring of Air Pollution (GMAP) vehicle, an all-electric vehicle measuring real-time concentrations of particulate and gaseous poll...

  3. Assessment of near-source air pollution at a fine spatial scale using a mobile monitoring method

    EPA Science Inventory

    Mobile monitoring is an emerging strategy to characterize spatially and temporally variable air pollution in areas near sources. EPA’s Geospatial Monitoring of Air Pollution (GMAP) vehicle, an all-electric vehicle measuring real-time concentrations of particulate and gaseou...

  4. Assessment of source-specific health effects associated with an unknown number of major sources of multiple air pollutants: a unified Bayesian approach.

    PubMed

    Park, Eun Sug; Hopke, Philip K; Oh, Man-Suk; Symanski, Elaine; Han, Daikwon; Spiegelman, Clifford H

    2014-07-01

    There has been increasing interest in assessing health effects associated with multiple air pollutants emitted by specific sources. A major difficulty with achieving this goal is that the pollution source profiles are unknown and source-specific exposures cannot be measured directly; rather, they need to be estimated by decomposing ambient measurements of multiple air pollutants. This estimation process, called multivariate receptor modeling, is challenging because of the unknown number of sources and unknown identifiability conditions (model uncertainty). The uncertainty in source-specific exposures (source contributions) as well as uncertainty in the number of major pollution sources and identifiability conditions have been largely ignored in previous studies. A multipollutant approach that can deal with model uncertainty in multivariate receptor models while simultaneously accounting for parameter uncertainty in estimated source-specific exposures in assessment of source-specific health effects is presented in this paper. The methods are applied to daily ambient air measurements of the chemical composition of fine particulate matter ([Formula: see text]), weather data, and counts of cardiovascular deaths from 1995 to 1997 for Phoenix, AZ, USA. Our approach for evaluating source-specific health effects yields not only estimates of source contributions along with their uncertainties and associated health effects estimates but also estimates of model uncertainty (posterior model probabilities) that have been ignored in previous studies. The results from our methods agreed in general with those from the previously conducted workshop/studies on the source apportionment of PM health effects in terms of number of major contributing sources, estimated source profiles, and contributions. However, some of the adverse source-specific health effects identified in the previous studies were not statistically significant in our analysis, which probably resulted because we

  5. Trends and sources vs air mass origins in a major city in South-western Europe: Implications for air quality management.

    PubMed

    Fernández-Camacho, R; de la Rosa, J D; Sánchez de la Campa, A M

    2016-05-15

    This study presents a 17-years air quality database comprised of different parameters corresponding to the largest city in the south of Spain (Seville) where atmospheric pollution is frequently attributed to traffic emissions and is directly affected by Saharan dust outbreaks. We identify the PM10 contributions from both natural and anthropogenic sources in this area associated to different air mass origins. Hourly, daily and seasonal variation of PM10 and gaseous pollutant concentrations (CO, NO2 and SO2), all of them showing negative trends during the study period, point to the traffic as one of the main sources of air pollution in Seville. Mineral dust, secondary inorganic compounds (SIC) and trace elements showed higher concentrations under North African (NAF) air mass origins than under Atlantic. We observe a decreasing trend in all chemical components of PM10 under both types of air masses, NAF and Atlantic. Principal component analysis using more frequent air masses in the area allows the identification of five PM10 sources: crustal, regional, marine, traffic and industrial. Natural sources play a more relevant role during NAF events (20.6 μg · m(-3)) than in Atlantic episodes (13.8 μg · m(-3)). The contribution of the anthropogenic sources under NAF doubles the one under Atlantic conditions (33.6 μg · m(-3) and 15.8 μg · m(-3), respectively). During Saharan dust outbreaks the frequent accumulation of local anthropogenic pollutants in the lower atmosphere results in poor air quality and an increased risk of mortality. The results are relevant when analysing the impact of anthropogenic emissions on the exposed population in large cities. The increase in potentially toxic elements during Saharan dust outbreaks should also be taken into account when discounting the number of exceedances attributable to non-anthropogenic or natural origins.

  6. Trends and sources vs air mass origins in a major city in South-western Europe: Implications for air quality management.

    PubMed

    Fernández-Camacho, R; de la Rosa, J D; Sánchez de la Campa, A M

    2016-05-15

    This study presents a 17-years air quality database comprised of different parameters corresponding to the largest city in the south of Spain (Seville) where atmospheric pollution is frequently attributed to traffic emissions and is directly affected by Saharan dust outbreaks. We identify the PM10 contributions from both natural and anthropogenic sources in this area associated to different air mass origins. Hourly, daily and seasonal variation of PM10 and gaseous pollutant concentrations (CO, NO2 and SO2), all of them showing negative trends during the study period, point to the traffic as one of the main sources of air pollution in Seville. Mineral dust, secondary inorganic compounds (SIC) and trace elements showed higher concentrations under North African (NAF) air mass origins than under Atlantic. We observe a decreasing trend in all chemical components of PM10 under both types of air masses, NAF and Atlantic. Principal component analysis using more frequent air masses in the area allows the identification of five PM10 sources: crustal, regional, marine, traffic and industrial. Natural sources play a more relevant role during NAF events (20.6 μg · m(-3)) than in Atlantic episodes (13.8 μg · m(-3)). The contribution of the anthropogenic sources under NAF doubles the one under Atlantic conditions (33.6 μg · m(-3) and 15.8 μg · m(-3), respectively). During Saharan dust outbreaks the frequent accumulation of local anthropogenic pollutants in the lower atmosphere results in poor air quality and an increased risk of mortality. The results are relevant when analysing the impact of anthropogenic emissions on the exposed population in large cities. The increase in potentially toxic elements during Saharan dust outbreaks should also be taken into account when discounting the number of exceedances attributable to non-anthropogenic or natural origins. PMID:26930305

  7. High brightness picosecond electron gun

    SciTech Connect

    Merano, M.; Collin, S.; Renucci, P.; Gatri, M.; Sonderegger, S.; Crottini, A.; Ganiere, J.D.; Deveaud, B.

    2005-08-15

    We have developed a high brightness picosecond electron gun. We have used it to replace the thermionic electron gun of a commercial scanning electron microscope (SEM) in order to perform time-resolved cathodoluminescence experiments. Picosecond electron pulses are produced, at a repetition rate of 80.7 MHz, by femtosecond mode-locked laser pulses focused on a metal photocathode. This system has a normalized axial brightness of 93 A/cm{sup 2} sr kV, allowing for a spatial resolution of 50 nm in the secondary electron imaging mode of the SEM. The temporal width of the electron pulse is 12 ps.

  8. Unintentional Gun Deaths among Children. Firearm Facts.

    ERIC Educational Resources Information Center

    Duker, Laurie, Ed.

    Children are at risk of being killed or injured by a gun if their parents own a gun because many guns obtained for self-defense are kept loaded and within reach of children. This brief fact sheet presents statistical information relating to accidental deaths involving young people and firearms. Safety measures are suggested for preventing…

  9. Advances in light-gas gun technology

    NASA Technical Reports Server (NTRS)

    Cowan, P. L.; Murphy, J. R.

    1968-01-01

    Constant-area accelerator used with light-gas guns increases the velocity of accelerating projectiles. A disposable accelerator on the muzzle of the gun uses the energy and momentum of a primary projectile, launched by the gun, to achieve high velocities of a light secondary projectile accelerated from rest in the accelerator.

  10. Determination of releaes from a fugitive or diffuse source using downwind air-monitoring and site-specific meteorological data

    SciTech Connect

    Culp, T.; Kovacic, J.; Deola, R.

    1996-12-31

    In order to demonstrate compliance with annual radiological dose limits, air-dispersion modeling is often performed. Many air-dispersion models calculate the effects of radionuclide releases. These models do not determine the actual release; they rely on either measured release data from the source or an estimate of the source release based on process knowledge. The EPA provides clear guidance for the determination of annual radionuclide releases from point sources (i.e. facility stacks and vents). However, clear guidance for the determination of radionuclide releases from diffuse or fugitive sources is not available.

  11. HVAC systems as emission sources affecting indoor air quality: A critical review. Final report, September 1993-June 1994

    SciTech Connect

    Batterman, S.; Burge, H.

    1995-02-01

    The study evaluates heating, ventilating and air conditioning (HVAC) systems as contaminant emission sources that affect indoor air quality (IAQ). Various literature sources and methods for characterizing HVAC emission sources are reviewed. Available methods include in situ tests, longitudinal and cross-sectional studies, and laboratory studies. Based on the available literature, several HVAC components are cited fairly frequently as emission sources, and there is broad agreement regarding their significance. IAQ problems appear to be exacerbated by dust accumulation and by the presence of fibrous insulation. Other problems include entrainment, migration, and infiltration of indoor and outdoor contaminants that are distributed to indoor spaces by the HVAC system.

  12. ILC @ SLAC R&D Program for a Polarized RF Gun

    SciTech Connect

    Clendenin, J.E.; Brachman, A.; Dowell, D.H.; Garwin, E.L.; Ioakemidi, K.; Kirby, R.E.; Maruyama, T.; Miller, R.A.; Prescott, C.Y.; Wang, J.W.; Lewellen, J.W.; Prepost, R.; /Wisconsin U., Madison

    2006-01-25

    Photocathode rf guns produce high-energy low-emittance electron beams. DC guns utilizing GaAs photocathodes have proven successful for generating polarized electron beams for accelerators, but they require rf bunching systems that significantly increase the transverse emittance of the beam. With higher extraction field and beam energy, rf guns can support higher current densities at the cathode. The source laser system can then be used to generate the high peak current, relatively low duty-factor micropulses required by the ILC without the need for post-extraction rf bunching. The net result is that the injection system for a polarized rf gun can be identical to that for an unpolarized rf gun. However, there is some uncertainty as to the survivability of an activated GaAs cathode in the environment of an operating rf gun. Consequently, before attempting to design a polarized rf gun for the ILC, SLAC plans to develop an rf test gun to demonstrate the rf operating conditions suitable for an activated GaAs cathode.

  13. Understanding of Guns, Gun Play, and Aggressivity Among 5-9 Year Old Children.

    ERIC Educational Resources Information Center

    LaVoie, Joseph C.; Adams, Gerald R.

    Knowledge about guns and the relation between play with guns and aggressivity was assessed in a group of 5-9 year old children. Each child was questioned about his gun play and his understanding of guns after he was shown a display of two toy and two real guns. This data was then correlated with a teacher rating of aggression for each child.…

  14. Evaluating sources of indoor air pollution. Report for March 1988-May 1989

    SciTech Connect

    Tichenor, B.A.; Sparks, L.E.; White, J.B.; Jackson, M.D.

    1990-04-01

    The article discusses a three-phase approach, employing environmental chambers, indoor air quality (IAQ) models, and test house experiments, that is effective in linking sources of indoor pollutants to measured concentrations. Emission factors developed in test chambers can be used to evaluate full-scale indoor environments. A PC-based IAQ model has been developed that can accurately predict indoor concentrations of specific pollutants under controlled conditions in a test house. The model is also useful in examining the effect of pollutant sinks and variations in ventilation parameters. Pollutants were examined from: para-dichlorobenzene emissions from moth crystal cakes, and particulate emissions from unvented kerosene heaters. However, the approach has not been validated for other source types.

  15. Cloud partitioning of isocyanic acid (HNCO) and evidence of secondary source of HNCO in ambient air

    NASA Astrophysics Data System (ADS)

    Zhao, R.; Lee, A. K. Y.; Wentzell, J. J. B.; Mcdonald, A. M.; Toom-Sauntry, D.; Leaitch, W. R.; Modini, R. L.; Corrigan, A. L.; Russell, L. M.; Noone, K. J.; Schroder, J. C.; Bertram, A. K.; Hawkins, L. N.; Abbatt, J. P. D.; Liggio, J.

    2014-10-01

    Although isocyanic acid (HNCO) may cause a variety of health issues via protein carbamylation and has been proposed as a key compound in smoke-related health issues, our understanding of the atmospheric sources and fate of this toxic compound is currently incomplete. To address these issues, a field study was conducted at Mount Soledad, La Jolla, CA, to investigate partitioning of HNCO to clouds and fogs using an Acetate Chemical Ionization Mass Spectrometer coupled to a ground-based counterflow virtual impactor. The first field evidence of cloud partitioning of HNCO is presented, demonstrating that HNCO is dissolved in cloudwater more efficiently than expected based on the effective Henry's law solubility. The measurements also indicate evidence for a secondary, photochemical source of HNCO in ambient air at this site.

  16. Impact of external industrial sources on the regional and local air quality of Mexico Megacity

    NASA Astrophysics Data System (ADS)

    Almanza, V. H.; Molina, L. T.; Li, G.; Fast, J.; Sosa, G.

    2013-10-01

    The air quality of megacities can be influenced by external emissions sources on both global and regional scale, and at the same time their outflow emissions can exert an important impact to the surrounding environment. The present study evaluates an SO2 peak observed on 24 March 2006 at the suburban supersite T1 and ambient air quality monitoring stations located in the north region of the Mexico City Metropolitan Area (MCMA) during MILAGRO campaign. We found that this peak could be related to an important episodic emission event from Tizayuca region, northeast of the MCMA. Back trajectories analyses suggest that the emission event started in the early morning at 04:00 LST and lasted for about 9 h. The estimated emission rate is noticeably high, about 2 kg s-1. This finding suggests the possibility of "overlooked" emission sources in this region that could influence the air quality of the MCMA. This further motivated us to study the cement plants, including those in the State of Hidalgo and in the State of Mexico, and we found that they can contribute in the NE region of the basin (about 41.7%), at the suburban supersite T1 (41.23%) and at some monitoring stations their contribution can be even higher than from the Tula Industrial Complex. The contribution of Tula Industrial Complex to regional ozone levels is estimated. The model suggests low contribution to the MCMA (1 ppb to 4 ppb) and slightly higher at the suburban T1 (6 ppb) and rural T2 (5 ppb) supersites. However, the contribution could be as high as 10 ppb in the upper northwest region of the basin and in the southwest and south-southeast regions of State of Hidalgo. In addition, a first estimate of the potential contribution from flaring activities to regional ozone levels is presented. Emission rates are estimated with a CFD combustion model. Results suggest that up to 30% of the total regional ozone from TIC could be related to flaring activities. Finally, the influence in SO2 levels from technological

  17. The Smoking Gun.

    ERIC Educational Resources Information Center

    Horrigan, Alice

    1994-01-01

    Examines the complex public debate over the risks of passive smoking that includes the issues of individual choice, personal space, community, social norms, and morality. Discusses the composition of ETS (gases and particulates that disperse into the air when a smoker smokes) and the efforts of tobacco lobbies. (LZ)

  18. High gradient rf gun studies of CsBr photocathodes

    DOE PAGES

    Vecchione, Theodore; Maldonado, Juan R.; Gierman, Stephen; Corbett, Jeff; Hartmann, Nick; Pianetta, Piero A.; Hesselink, Lambertus; Schmerge, John F.

    2015-04-03

    CsBr photocathodes have 10 times higher quantum efficiency with only 3 times larger intrinsic transverse emittance than copper. They are robust and can withstand 80 MV/m fields without breaking down or emitting dark current. They can operate in 2×10⁻⁹ torr vacuum and survive exposure to air. They are well suited for generating high pulse charge in rf guns without a photocathode transfer system.

  19. High gradient rf gun studies of CsBr photocathodes

    NASA Astrophysics Data System (ADS)

    Vecchione, Theodore; Maldonado, Juan R.; Gierman, Stephen; Corbett, Jeff; Hartmann, Nick; Pianetta, Piero A.; Hesselink, Lambertus; Schmerge, John F.

    2015-04-01

    CsBr photocathodes have 10 times higher quantum efficiency with only 3 times larger intrinsic transverse emittance than copper. They are robust and can withstand 80 MV /m fields without breaking down or emitting dark current. They can operate in 2 ×10-9 torr vacuum and survive exposure to air. They are well suited for generating high pulse charge in rf guns without a photocathode transfer system.

  20. Chamber Bioaerosol Study: Outdoor Air and Human Occupants as Sources of Indoor Airborne Microbes

    PubMed Central

    Adams, Rachel I.; Bhangar, Seema; Pasut, Wilmer; Arens, Edward A.; Taylor, John W.; Lindow, Steven E.; Nazaroff, William W.; Bruns, Thomas D.

    2015-01-01

    Human occupants are an important source of microbes in indoor environments. In this study, we used DNA sequencing of filter samples to assess the fungal and bacterial composition of air in an environmental chamber under different levels of occupancy, activity, and exposed or covered carpeting. In this office-like, mechanically ventilated environment, results showed a strong influence of outdoor-derived particles, with the indoor microbial composition tracking that of outdoor air for the 2-hour sampling periods. The number of occupants and their activity played a significant but smaller role influencing the composition of indoor bioaerosols. Human-associated taxa were observed but were not particularly abundant, except in the case of one fungus that appeared to be transported into the chamber on the clothing of a study participant. Overall, this study revealed a smaller signature of human body-associated taxa than had been expected based on recent studies of indoor microbiomes, suggesting that occupants may not exert a strong influence on bioaerosol microbial composition in a space that, like many offices, is well ventilated with air that is moderately filtered and moderately occupied. PMID:26024222

  1. PAHs pollution from traffic sources in air of Hangzhou, China: trend and influencing factors.

    PubMed

    Zhu, Li-Zhong; Wang, Jing

    2005-01-01

    PAHs pollution in air of arterial roads was investigated from October 1998 to October 2001 in Hangzhou, China. The results showed that sigma10 PAHs was 13-36 microg/m3, among which, BaP, a strong carcinogenic kind ranged from 0.034 microg/m3 to 0.12 microg/m3. PAHs pollutions in four seasons were winter > autumn > spring-summer. The annual averages of sigmaPAHs concentration were 25 microg/m3 for 1999, 28 microg/m3 for 2000, and 29 microg/m3 for 2001, respectively. Leaded gasoline was banned in December 1998 in Hangzhou, thus comparative measurements with PAHs in leaded and lead-free gasoline powered motor exhausts made it certain that the use of lead-free gasoline leaded to a heavier PAHs pollution in roadside air from December, 1998, in China, and sigmaPAHs in air samples after the lead-banning were more than twice of that in samples before the action. For the large contribution of vehicle discharge to air pollution in roadside, further research was performed to suggest the factors influencing PAHs distribution in vehicle exhaust in order to control air pollution effectively. Compared to gasoline engines, emissions from diesel engines were less toxic, although they might produce more PAHs. Of the same vehicular and oil type, automobiles of longer mileages produced more toxic PAHs. PAHs distributions in the vehicular exhausts were related to the oil type. Large difference was found in the abundance of 3-, 5- and 6-ring PAHs between exhausts from gasoline and diesel oil engines. Diesel oil engines produced relative lighter PAHs such as NAPH, ACEN, FLUOR, while gasoline engines emitted heavier kinds such as BkF, IN and BP. The automobile produced more PAHs with the increase of mileage especially FLUR, PY, BaP, BP. Some significant ratios for traffic source in Hangzhou such as PHEN/AN, FLUR/PY, IN/BP were 0.50-4.3, 0.58-7.4, 0.51-1.5, respectively. A source fingerprint for vehicle exhausts of a mixture of vehicle and oil types in the city district for light

  2. DIESEL TRUCK IDLING EMISSIONS - MOBILE SOURCE AIR TOXICS MEASURED AT A HOT SPOT

    SciTech Connect

    Parks, II, James E; Storey, John Morse; Miller, Terry L.; Fu, Joshua S.; Hromis, Boris

    2007-01-01

    Mobile Source Air Toxics (MSATs) are of growing concern due to recent studies linking health risk to residency near heavily traveled roadways. Few research studies on MSAT emissions have been performed due to several factors; those factors include: the difficulty of measuring MSATs due to their semi-volatile nature, lower relative concentration in comparison to NOx and other criteria emissions, and fewer regulations on MSATs. In this paper, measurements of MSATs at a "hot spot" of poor air quality created by a high population of idling heavy-duty trucks are presented. The study area was the Watt Road-Interstate-40/75 interchange just west of Knoxville, TN where approximately 20,000 heavy-duty trucks travel along the interstate each day and hundreds of heavy-duty trucks idle at three large truck stops near the interchange. The air quality in the local area surrounding the interchange is affected negatively by the high number of mobile sources as well as geographic and meteorological conditions; the interchange lies in a valley between two ridges which slows long range transport of pollutants especially in winter months when temperature inversion occurs frequently. Ambient air quality was measured during summer and winter months of two separate years at three sites: a site in one of the truckstops, a site near the interstate roadway, and a site on top of one of the surrounding ridges chosen as a background site for comparison. Results of criteria pollutants measured at these sites are reported in a companion paper by Miller et. al.; the results presented here include measurements of MSATs such as formaldehyde, acetaldehyde, acrolein, and other species obtained via collection on di-nitrophenyl hydrazine (DNPH) filters. Also, preliminary measurements of poly-aromatic hydrocarbons are presented. The results indicate that emissions from idling heavy-duty trucks are a primary contributor of MSATs to local air quality near areas of high static truck traffic; furthermore

  3. Characteristics of aerodynamic sound sources generated by coiled wires in a uniform air-flow

    NASA Astrophysics Data System (ADS)

    Matsumoto, H.; Nishida, K.; Saitoh, K.

    2003-11-01

    This study deals experimentally with aerodynamic sounds generated by coiled wires in a uniform air-flow. The coiled wire is a model of the hair dryer's heater. In the experiment, the effects of the coil diameter D, wire diameter d and coil spacing s of the coiled wire on the aerodynamic sound have been clarified. The results of frequency analyses of the aerodynamic sounds show that an Aeolian sound is generated by the coiled wire, when s/d is larger than 1. Also the peak frequencies of Aeolian sounds generated by the coiled wires are higher than the ones generated by a straight cylinder having the same diameter d. To clarify the characteristics of the aerodynamic sound sources, the directivity of the aerodynamic sound generated by the coiled wire has been examined, and the coherent function between the velocity fluctuation around the coiled wire and the aerodynamic sound has been calculated. Moreover, the band overall value of coherent output power between the sound and the velocity fluctuations has been calculated. This method has clarified the sound source region of the Aeolian sound generated by the coiled wire. These results show that the Aeolian sound is generated by the arc part of the coiled wire, which is located in the upstream side of the air-flow.

  4. Source apportionment of PM(2.5) and selected hazardous air pollutants in Seattle.

    PubMed

    Wu, Chang-fu; Larson, Timothy V; Wu, Szu-Ying; Williamson, John; Westberg, Hal H; Liu, L-J Sally

    2007-11-01

    The potential benefits of combining the speciated PM(2.5) and VOCs data in source apportionment analysis for identification of additional sources remain unclear. We analyzed the speciated PM(2.5) and VOCs data collected at the Beacon Hill in Seattle, WA between 2000 and 2004 with the Multilinear Engine (ME-2) to quantify source contributions to the mixture of hazardous air pollutants (HAPs). We used the 'missing mass', defined as the concentration of the measured total particle mass minus the sum of all analyzed species, as an additional variable and implemented an auxiliary equation to constrain the sum of all species mass fractions to be 100%. Regardless of whether the above constraint was implemented and/or the additional VOCs data were included with the PM(2.5) data, the models identified that wood burning (24%-31%), secondary sulfate (20%-24%) and secondary nitrate (15%-20%) were the main contributors to PM(2.5). Using only PM(2.5) data, the model distinguished two diesel features with the 100% constraint, but identified only one diesel feature without the constraint. When both PM(2.5) and VOCs data were used, one additional feature was identified as the major contributor (26%) to total VOC mass. Adding VOCs data to the speciated PM(2.5) data in source apportionment modeling resulted in more accurate source contribution estimates for combustion related sources as evidenced by the less 'missing mass' percentage in PM(2.5). Using the source contribution estimates, we evaluated the validity of using black carbon (BC) as a surrogate for diesel exhaust. We found that BC measured with an aethalometer at 370 nm and 880 nm had reasonable correlations with the estimated concentrations of diesel particulate matters (r>0.7), as well as with the estimated concentrations of wood burning particles during the heating seasons (r=0.56-0.66). This indicates that the BC is not a unique tracer for either source. The difference in BC between 370 and 880 nm, however, correlated

  5. A simple method for screening emission sources of carbonyl compounds in indoor air.

    PubMed

    Yamashita, Shohei; Kume, Kazunari; Horiike, Toshiyuki; Honma, Nobuyuki; Fusaya, Masahiro; Ohura, Takeshi; Amagai, Takashi

    2010-06-15

    Volatile organic compounds (VOCs) emitted from building and furnishing materials are frequently observed in high concentrations in indoor air. Nondestructive analytical methods that determine the main parameters influencing concentration of the chemical substances are necessary to screen for sources of VOC emissions. Toward this goal, we have developed a new flux sampler, referred to herein as an emission cell for simultaneous multi-sampling (ECSMS), that is used for screening indoor emission sources of VOCs and for determining the emission rates of these sources. Because the ECSMS is based on passive sampling, it can be easily used on-site at a low cost. Among VOCs, low-molecular-weight carbonyl compounds including formaldehyde are frequently detected at high concentrations in indoor environments. In this study, we determined the reliability of the ECSMS for the collection of formaldehyde and other carbonyl compounds emitted from wood-based composites of medium density fiberboards and particleboards. We then used emission rates determined by the ECSMS to predict airborne concentrations of formaldehyde emitted from a bookshelf in a large chamber, and these data were compared to formaldehyde concentrations that were acquired simultaneously by means of an active sampling method. The values obtained from the two methods were quite similar, suggesting that ECSMS measurement is an effective method for screening primary sources influencing indoor concentrations of formaldehyde. PMID:20149530

  6. Impact of external industrial sources on the regional and local air quality of Mexico Megacity

    NASA Astrophysics Data System (ADS)

    Almanza, Victor; Molina, Luisa T.; Li, Guohui; Fast, Jerome; Sosa, Gustavo

    2014-05-01

    The air quality of megacities can be influenced by external emissions sources on both regional and global scales. At the same time their outflow emissions can exert an important impact to the surrounding environment. The present study evaluates an SO2 peak observed on 24 March 2006 at the suburban supersite and ambient air quality monitoring stations located in the northern region of the Mexico City Metropolitan Area (MCMA) during MILAGRO campaign. We found that this peak could be related to an important episodic emission event coming from Tizayuca region, northeast of the MCMA. Back trajectories analyses suggest that the emission event started in the early morning at 04:00 LST and lasted for about 9 hours. The estimated emission rate is high, about 2 kg s-1. This finding suggests the possibility of 'overlooked' emission sources in Tizayuca region that could influence the air quality of the MCMA. This further motivated us to study the cement plants, including those in the State of Hidalgo and the State of Mexico. We found that they can also contribute SO2 in the NE region of the basin, at the suburban supersite and that at some monitoring stations; their contribution can be even higher than from the Tula Industrial Complex (TIC). The contribution of TIC to regional ozone levels is also estimated. The model suggests low contribution to the MCMA and slightly higher contribution at the suburban and rural supersites. However, the contribution could be high in the upper northwest region of the basin and in the southwest and south-southeast regions of the State of Hidalgo. In addition, a first estimate of the potential contribution from flaring activities to regional ozone levels is presented. Results suggest that part of the total regional ozone from TIC-generated precursors could be related to flaring activities.

  7. Air pollutant emissions from Chinese households: A major and underappreciated ambient pollution source.

    PubMed

    Liu, Jun; Mauzerall, Denise L; Chen, Qi; Zhang, Qiang; Song, Yu; Peng, Wei; Klimont, Zbigniew; Qiu, Xinghua; Zhang, Shiqiu; Hu, Min; Lin, Weili; Smith, Kirk R; Zhu, Tong

    2016-07-12

    As part of the 12th Five-Year Plan, the Chinese government has developed air pollution prevention and control plans for key regions with a focus on the power, transport, and industrial sectors. Here, we investigate the contribution of residential emissions to regional air pollution in highly polluted eastern China during the heating season, and find that dramatic improvements in air quality would also result from reduction in residential emissions. We use the Weather Research and Forecasting model coupled with Chemistry to evaluate potential residential emission controls in Beijing and in the Beijing, Tianjin, and Hebei (BTH) region. In January and February 2010, relative to the base case, eliminating residential emissions in Beijing reduced daily average surface PM2.5 (particulate mater with aerodynamic diameter equal or smaller than 2.5 micrometer) concentrations by 14 ± 7 μg⋅m(-3) (22 ± 6% of a baseline concentration of 67 ± 41 μg⋅m(-3); mean ± SD). Eliminating residential emissions in the BTH region reduced concentrations by 28 ± 19 μg⋅m(-3) (40 ± 9% of 67 ± 41 μg⋅m(-3)), 44 ± 27 μg⋅m(-3) (43 ± 10% of 99 ± 54 μg⋅m(-3)), and 25 ± 14 μg⋅m(-3) (35 ± 8% of 70 ± 35 μg⋅m(-3)) in Beijing, Tianjin, and Hebei provinces, respectively. Annually, elimination of residential sources in the BTH region reduced emissions of primary PM2.5 by 32%, compared with 5%, 6%, and 58% achieved by eliminating emissions from the transportation, power, and industry sectors, respectively. We also find air quality in Beijing would benefit substantially from reductions in residential emissions from regional controls in Tianjin and Hebei, indicating the value of policies at the regional level. PMID:27354524

  8. Air pollutant emissions from Chinese households: A major and underappreciated ambient pollution source

    PubMed Central

    Liu, Jun; Mauzerall, Denise L.; Chen, Qi; Zhang, Qiang; Song, Yu; Peng, Wei; Klimont, Zbigniew; Qiu, Xinghua; Zhang, Shiqiu; Hu, Min; Lin, Weili; Smith, Kirk R.; Zhu, Tong

    2016-01-01

    As part of the 12th Five-Year Plan, the Chinese government has developed air pollution prevention and control plans for key regions with a focus on the power, transport, and industrial sectors. Here, we investigate the contribution of residential emissions to regional air pollution in highly polluted eastern China during the heating season, and find that dramatic improvements in air quality would also result from reduction in residential emissions. We use the Weather Research and Forecasting model coupled with Chemistry to evaluate potential residential emission controls in Beijing and in the Beijing, Tianjin, and Hebei (BTH) region. In January and February 2010, relative to the base case, eliminating residential emissions in Beijing reduced daily average surface PM2.5 (particulate mater with aerodynamic diameter equal or smaller than 2.5 micrometer) concentrations by 14 ± 7 μg⋅m−3 (22 ± 6% of a baseline concentration of 67 ± 41 μg⋅m−3; mean ± SD). Eliminating residential emissions in the BTH region reduced concentrations by 28 ± 19 μg⋅m−3 (40 ± 9% of 67 ± 41 μg⋅m−3), 44 ± 27 μg⋅m−3 (43 ± 10% of 99 ± 54 μg⋅m−3), and 25 ± 14 μg⋅m−3 (35 ± 8% of 70 ± 35 μg⋅m−3) in Beijing, Tianjin, and Hebei provinces, respectively. Annually, elimination of residential sources in the BTH region reduced emissions of primary PM2.5 by 32%, compared with 5%, 6%, and 58% achieved by eliminating emissions from the transportation, power, and industry sectors, respectively. We also find air quality in Beijing would benefit substantially from reductions in residential emissions from regional controls in Tianjin and Hebei, indicating the value of policies at the regional level. PMID:27354524

  9. Air pollutant emissions from Chinese households: A major and underappreciated ambient pollution source.

    PubMed

    Liu, Jun; Mauzerall, Denise L; Chen, Qi; Zhang, Qiang; Song, Yu; Peng, Wei; Klimont, Zbigniew; Qiu, Xinghua; Zhang, Shiqiu; Hu, Min; Lin, Weili; Smith, Kirk R; Zhu, Tong

    2016-07-12

    As part of the 12th Five-Year Plan, the Chinese government has developed air pollution prevention and control plans for key regions with a focus on the power, transport, and industrial sectors. Here, we investigate the contribution of residential emissions to regional air pollution in highly polluted eastern China during the heating season, and find that dramatic improvements in air quality would also result from reduction in residential emissions. We use the Weather Research and Forecasting model coupled with Chemistry to evaluate potential residential emission controls in Beijing and in the Beijing, Tianjin, and Hebei (BTH) region. In January and February 2010, relative to the base case, eliminating residential emissions in Beijing reduced daily average surface PM2.5 (particulate mater with aerodynamic diameter equal or smaller than 2.5 micrometer) concentrations by 14 ± 7 μg⋅m(-3) (22 ± 6% of a baseline concentration of 67 ± 41 μg⋅m(-3); mean ± SD). Eliminating residential emissions in the BTH region reduced concentrations by 28 ± 19 μg⋅m(-3) (40 ± 9% of 67 ± 41 μg⋅m(-3)), 44 ± 27 μg⋅m(-3) (43 ± 10% of 99 ± 54 μg⋅m(-3)), and 25 ± 14 μg⋅m(-3) (35 ± 8% of 70 ± 35 μg⋅m(-3)) in Beijing, Tianjin, and Hebei provinces, respectively. Annually, elimination of residential sources in the BTH region reduced emissions of primary PM2.5 by 32%, compared with 5%, 6%, and 58% achieved by eliminating emissions from the transportation, power, and industry sectors, respectively. We also find air quality in Beijing would benefit substantially from reductions in residential emissions from regional controls in Tianjin and Hebei, indicating the value of policies at the regional level.

  10. Keeping Guns Out of Schools.

    ERIC Educational Resources Information Center

    McGiboney, Garry W.

    1995-01-01

    The DeKalb County (Georgia) School System has reduced the number of gun-toting students by over 65% by piecing together a program combining education, community involvement, mandatory expulsion, and video technology. Kids do their part by learning the school's discipline policy, discussing nonviolent alternatives, and carrying clear bookbags. (MLH)

  11. Youth, guns, and violent crime.

    PubMed

    Blumstein, Alfred

    2002-01-01

    Young people are overrepresented as both victims and perpetrators of violence. Indeed, some commentators have suggested that recent cohorts of youth have been composed of "superpredators" who have little regard for human life. The evidence, however, suggests that other factors are responsible for recent increases in youth gun violence. This article analyzes the extent and causes of youth violence in the United States, paying particular attention to the late 1980s and early 1990s, when rates of homicide and robbery committed by youth rose to extremely high levels. Examination of trends for these crimes shows that: The increase in violence in the United States during the late 1980s and early 1990s was due primarily to an increase in violent acts committed by people under age 20. Similarly, dramatic declines in homicide and robbery in recent years are attributable primarily to a decline in youth violence. The increase in youth homicide was predominantly due to a significant increase in the use of handguns, which converted ordinary teenage fights and other violent encounters into homicides. Several other interrelated factors also fueled the rise in youth violence, including the rise of illegal drug markets, particularly for crack cocaine, the recruitment of youth into those markets, and an increase in gun carrying among young people. The author points out that youth violence diminished as the crack markets shrank, law enforcement increased efforts to control youth access to guns, youth gun carrying declined, and the robust economy provided legitimate jobs for young people.

  12. Guns in Schools. Firearm Facts.

    ERIC Educational Resources Information Center

    Duker, Laurie, Ed.

    Common reasons that young people choose to carry firearms outside of school--protection, intimidation of others, or to be like their peers--are the same reasons they carry guns into the school. This fact sheet presents statistics regarding the prevalence of firearms amongst students in American schools, including: shooting fatalities and woundings…

  13. Traffic source emission and street level air pollution in urban areas of Guangzhou, South China (P.R.C.)

    NASA Astrophysics Data System (ADS)

    Qin, Y.; Chan, L. Y.

    Street level air pollution due to traffic emission is a cause of concern in Guangzhou City. During the winter and summer of 1988, the traffic-related air pollutant concentrations, wind field, traffic volume and vehicle speed were measured extensively in three types of street canyons in Guangzhou City. Various types of motor vehicle emission in idle condition were measured and the composite emission factors of vehicles were derived. The variation of traffic volume and vehicle speed in 223 mainstreets were also investigated. The annual air pollutant concentration levels of traffic source emission were calculated. Using CO as a traffic emission tracer for air pollution on the street, the contributions of traffic emission to street level air pollution were determined by the receptor method. Ground level air pollution in Guangzhou has changed from coal combustion emission type into traffic source emission type. The average contributions of traffic source emission to the concentration of CO and NO x on the street in 1988 are about 87% and 67%. The most significant pollutant of ambient air quality that traffic source emission influences in NO x.

  14. Analysis of the United States Air Force nonpoint-source water-pollution-abatement program. Master's thesis

    SciTech Connect

    Seaman, T.G.

    1990-09-01

    This theses examined the Air Force nonpoint source pollution abatement program by evaluating Major Command, Air Force Regional Civil Engineer and installations compliance to the official Air Force policy. Seventy-two installations in 37 states and ten Major Commands were represented in the data. The evaluation classified nonpoint source pollutants into five categories: urban, agricultural, construction, silvacultural and other. The research showed that most of the Major Command abatement programs were adequately meeting the needs of the Air Force. Two Air Force Regional Civil Engineers were evaluated. It was determined that one of these organizations had taken the necessary steps to implement nonpoint source abatement at the installations within their jurisdiction. The other organization was found to have a lack of current state regulatory information. Installation compliance was inconclusive due to the ambiguous, unstructured nature of the data. The major conclusion of this study was the need for the Air Force installations to implement more comprehensive nonpoint source pollution abatement programs. Elements of these programs range from educating the installations' populaces to implementing nonstructural best management practices such as including nonpoint source pollution abatement in Natural Resources Plans.

  15. RF Design of the LCLS Gun

    SciTech Connect

    Limborg-Deprey, C

    2010-12-13

    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, 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.

  16. 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.

  17. Field Operations and Enforcement Manual for Air Pollution Control. Volume II: Control Technology and General Source Inspection.

    ERIC Educational Resources Information Center

    Weisburd, Melvin I.

    The Field Operations and Enforcement Manual for Air Pollution Control, Volume II, explains in detail the following: technology of source control, modification of operations, particulate control equipment, sulfur dioxide removal systems for power plants, and control equipment for gases and vapors; inspection procedures for general sources, fuel…

  18. Stationary source sampling report: Ambient and source volatile organic compound testing, Production air stripper unit 1 (PASU-1) and pilot air stripper (PAS)

    SciTech Connect

    Not Available

    1984-09-05

    Tests were performed to measure the ambient concentrations of perchloroethylene, trichloroethylene, and 1,1,1-trichloroethane in the A/M area and to determine, for compliance purposes, the emissions and concentrations of those compounds issued from the Production Air Stripper Unit 1 (PASU-1) column and from the Pilot Air Stripper (PAS) column.

  19. The status of normal conducting RF (NCRF) guns; a summary of the ERL2005 Workshop

    SciTech Connect

    D.H. Dowell; J.W. Lewellen; D. Nguyen; R.A. Rimmer

    2005-03-19

    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%DF 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.

  20. The Status of Normal Conducting RF (NCRF) Guns, a Summary of the ERL2005 Workshop

    SciTech Connect

    Dowell, D.H.; Lewellen, J.W.; Nguyen, D.; Rimmer, R.; /Jefferson Lab

    2006-03-13

    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%DF 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.

  1. On the Ratio of Sulfur Dioxide to Nitrogen Oxides as an Indicator of Air Pollution Sources.

    NASA Astrophysics Data System (ADS)

    Nirel, Ronit; Dayan, Uri

    2001-07-01

    The ratio of sulfur dioxide to nitrogen oxides (RSN = SO2/NOx) is one indicator of air pollution sources. The role of this ratio in source attribution is illustrated here for the Ashdod area, located in the southern coastal plain of Israel. The main sources of pollution in the area are the tall stacks of the Eshkol power plant, the stacks of oil refineries, and areal sources (stationary and mobile). The factors that affect RSN are studied using four regression models: a binary regression tree in original scale, a tree in logarithmic scale, a data partition produced by a combination of the two trees, and a linear regression model. All models have similar relative prediction error, with the combined partition best highlighting the sources of variability in RSN: (a) very low values (interquartile range of [0.12, 0.48]) are associated with traffic, (b) low values ([0.43, 1.00]) are attributed to the power plant and to daytime emissions of local industry, (c) medium values ([0.74, 1.90]) are associated with local industry emissions during cooler hours of the day and refinery emissions mainly on slow wind episodes, and (d) high values ([1.07, 4.30]) are attributed to refinery emissions during moderate to fast wind episodes. Analysis of the number of episodes of increased concentrations indicates that, during 1996 and 1997, about 42% of SO2 episodes are attributable to the power plant and 33% to the refineries. Increased-NOx episodes are mainly contributed by traffic (91%) and power plant (4.5%) emissions.

  2. A Critical Review of Naphthalene Sources and Exposures Relevant to Indoor and Outdoor Air

    PubMed Central

    Jia, Chunrong; Batterman, Stuart

    2010-01-01

    Both the recent classification of naphthalene as a possible human carcinogen and its ubiquitous presence motivate this critical review of naphthalene’s sources and exposures. We evaluate the environmental literature on naphthalene published since 1990, drawing on nearly 150 studies that report emissions and concentrations in indoor, outdoor and personal air. While naphthalene is both a volatile organic compound and a polycyclic aromatic hydrocarbon, concentrations and exposures are poorly characterized relative to many other pollutants. Most airborne emissions result from combustion, and key sources include industry, open burning, tailpipe emissions, and cigarettes. The second largest source is off-gassing, specifically from naphthalene’s use as a deodorizer, repellent and fumigant. In the U.S., naphthalene’s use as a moth repellant has been reduced in favor of para-dichlorobenzene, but extensive use continues in mothballs, which appears responsible for some of the highest indoor exposures, along with off-label uses. Among the studies judged to be representative, average concentrations ranged from 0.18 to 1.7 μg m−3 in non-smoker’s homes, and from 0.02 to 0.31 μg m−3 outdoors in urban areas. Personal exposures have been reported in only three European studies. Indoor sources are the major contributor to (non-occupational) exposure. While its central tendencies fall well below guideline levels relevant to acute health impacts, several studies have reported maximum concentrations exceeding 100 μg m−3, far above guideline levels. Using current but draft estimates of cancer risks, naphthalene is a major environmental risk driver, with typical individual risk levels in the 10−4 range, which is high and notable given that millions of individuals are exposed. Several factors influence indoor and outdoor concentrations, but the literature is inconsistent on their effects. Further investigation is needed to better characterize naphthalene’s sources and

  3. Indoor air quality in Portuguese schools: levels and sources of pollutants.

    PubMed

    Madureira, J; Paciência, I; Pereira, C; Teixeira, J P; Fernandes, E de O

    2016-08-01

    Indoor air quality (IAQ) parameters in 73 primary classrooms in Porto were examined for the purpose of assessing levels of volatile organic compounds (VOCs), aldehydes, particulate matter, ventilation rates and bioaerosols within and between schools, and potential sources. Levels of VOCs, aldehydes, PM2.5 , PM10 , bacteria and fungi, carbon dioxide (CO2 ), carbon monoxide, temperature and relative humidity were measured indoors and outdoors and a walkthrough survey was performed concurrently. Ventilation rates were derived from CO2 and occupancy data. Concentrations of CO2 exceeding 1000 ppm were often encountered, indicating poor ventilation. Most VOCs had low concentrations (median of individual species <5 μg/m(3) ) and were below the respective WHO guidelines. Concentrations of particulate matter and culturable bacteria were frequently higher than guidelines/reference values. The variability of VOCs, aldehydes, bioaerosol concentrations, and CO2 levels between schools exceeded the variability within schools. These findings indicate that IAQ problems may persist in classrooms where pollutant sources exist and classrooms are poorly ventilated; source control strategies (related to building location, occupant behavior, maintenance/cleaning activities) are deemed to be the most reliable for the prevention of adverse health consequences in children in schools.

  4. Sources of Bacteria in Outdoor Air across Cities in the Midwestern United States ▿ †

    PubMed Central

    Bowers, Robert M.; Sullivan, Amy P.; Costello, Elizabeth K.; Collett, Jeff L.; Knight, Rob; Fierer, Noah

    2011-01-01

    Bacteria are abundant in the atmosphere, where they often represent a major portion of the organic aerosols. Potential pathogens of plants and livestock are commonly dispersed through the atmosphere, and airborne bacteria can have important effects on human health as pathogens or triggers of allergic asthma and seasonal allergies. Despite their importance, the diversity and biogeography of airborne microorganisms remain poorly understood. We used high-throughput pyrosequencing to analyze bacterial communities present in the aerosol fraction containing fine particulate matter of ≤2.5 μm from 96 near-surface atmospheric samples collected from cities throughout the midwestern United States and found that the communities are surprisingly diverse and strongly affected by the season. We also directly compared the airborne communities to those found in hundreds of samples representing potential source environments. We show that, in addition to the more predictable sources (soils and leaf surfaces), fecal material, most likely dog feces, often represents an unexpected source of bacteria in the atmosphere at more urbanized locations during the winter. Airborne bacteria are clearly an important, but understudied, component of air quality that needs to be better integrated into efforts to measure and model pollutants in the atmosphere. PMID:21803902

  5. Sources of bacteria in outdoor air across cities in the midwestern United States.

    PubMed

    Bowers, Robert M; Sullivan, Amy P; Costello, Elizabeth K; Collett, Jeff L; Knight, Rob; Fierer, Noah

    2011-09-01

    Bacteria are abundant in the atmosphere, where they often represent a major portion of the organic aerosols. Potential pathogens of plants and livestock are commonly dispersed through the atmosphere, and airborne bacteria can have important effects on human health as pathogens or triggers of allergic asthma and seasonal allergies. Despite their importance, the diversity and biogeography of airborne microorganisms remain poorly understood. We used high-throughput pyrosequencing to analyze bacterial communities present in the aerosol fraction containing fine particulate matter of ≤2.5 μm from 96 near-surface atmospheric samples collected from cities throughout the midwestern United States and found that the communities are surprisingly diverse and strongly affected by the season. We also directly compared the airborne communities to those found in hundreds of samples representing potential source environments. We show that, in addition to the more predictable sources (soils and leaf surfaces), fecal material, most likely dog feces, often represents an unexpected source of bacteria in the atmosphere at more urbanized locations during the winter. Airborne bacteria are clearly an important, but understudied, component of air quality that needs to be better integrated into efforts to measure and model pollutants in the atmosphere.

  6. 77 FR 75739 - National Emission Standards for Hazardous Air Pollutants for Chemical Manufacturing Area Sources

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-21

    ... Control Technology HAP Hazardous Air Pollutants HON National Emission Standards for Organic Hazardous Air Pollutants From the Synthetic Organic Chemical Manufacturing Industry ICR Information Collection Request lb... Hazardous Air Pollutants: Miscellaneous Organic Chemical Manufacturing MSDS Material Safety Data...

  7. Commissioning Results of the 2nd 3.5 Cell SRF Gun for ELBE

    SciTech Connect

    Arnold, A; Freitag, M; Murcek, Petr; Teichert, Jochen; Vennekate, H; Xiang, R; Ciovati, Gianluigi; Kneisel, Peter K.; Turlington, Larry D,

    2014-12-01

    As in 2007 the first 3.5 cell superconducting radio frequency (SRF) gun was taken into operation, it turned out that the specified performance has not been achieved. However, to demonstrate the full potential of this new type of electron source, a second and slightly modified SRF gun II was built in collaboration with Thomas Jefferson National Accelerator Facility (TJNAF). We will report on commissioning and first results of the new gun, which includes in particular the characterization of the most important RF properties as well as their comparison with previous vertical test results.

  8. One century of air deposition of hydrocarbons recorded in travertine in North Tibetan Plateau, China: Sources and evolution.

    PubMed

    Yuan, Guo-Li; Wu, Ming-Zhe; Sun, Yong; Li, Jun; Li, Jing-Chao; Wang, Gen-Hou

    2016-08-01

    The characteristic distribution patterns of hydrocarbons have been used for fingerprinting to identify their sources. The historical air depositions of hydrocarbons recorded in natural media help to understand the evolution of the air environment. Travertine is a natural acceptor of air deposition that settles on the ground layer by layer. To reconstruct the historical air environment of hydrocarbons in the North Tibetan Plateau (NTP), a unique background region, twenty-seven travertine samples were collected systematically from a travertine column according to its precipitated year. For each sample, the precipitated year was dated while n-alkanes and polycyclic aromatic hydrocarbons (PAHs) were determined. Based on source identification, the air environment of hydrocarbons in the past century was studied for the region of NTP. Before World War II, the anthropogenic sources of hydrocarbons showed little influence on the air environment. During World War II and China's War of Liberation, hydrocarbons increased significantly, mainly from the use of fossil fuels. Between 1954 and 1963, hydrocarbons in the air decreased significantly because the sources of petroleum combustion decreased. From the mid-1960s through the end of the 1990s, air hydrocarbons, which mainly originated from biomass burning, increased gradually because agriculture and animal husbandry were developing steadily in Tibet and China. From the late 1990s, hydrocarbons in the atmosphere increased rapidly due to the rapid increase of tourism activities, which might increase hydrocarbon emissions from traffic. The reconstruction of the historical air hydrocarbons in NTP clearly reflects the evolution of the region and global development. PMID:27101457

  9. Methods proposed to achieve air quality standards for mobile sources and technology surveillance.

    PubMed Central

    Piver, W T

    1975-01-01

    The methods proposed to meet the 1975 Standards of the Clean Air Act for mobile sources are alternative antiknocks, exhaust emission control devices, and alternative engine designs. Technology surveillance analysis applied to this situation is an attempt to anticipate potential public and environmental health problems from these methods, before they happen. Components of this analysis are exhaust emission characterization, environmental transport and transformation, levels of public and environmental exposure, and the influence of economics on the selection of alternative methods. The purpose of this presentation is to show trends as a result of the interaction of these different components. In no manner can these trends be interpreted explicitly as to what will really happen. Such an analysis is necessary so that public and environmental health officials have the opportunity to act on potential problems before they become manifest. PMID:50944

  10. Supplement B to compilation of air pollutant emission factors, volume 1. Stationary point and area sources

    SciTech Connect

    1996-11-01

    This document contains emission factors and process information for more than 200 air pollution source categories. This Supplement to AP-42 addresses pollutant-generating activity from Bituminous And Subbituminous Coal Combustion, Anthracite Coal Combustion, Fuel Oil Combustion, Natural Gas Combustion, Liquefied Petroleum Gas Combustion, Wood Waste Combustion In Boilers, Lignite Combustion, Bagasse Combustion In Sugar Mills, Residential Fireplaces, Residential Wood Stoves, Waste Oil Combustion, Stationary Gas Turbines For Electricity Generation, Heavy-duty Natural Gas-fired Pipeline Compressor Engines And Turbines, Gasoline and Diesel Industrial Engines, Large Stationary Diesel And All Stationary Dual-fuel Engines, Adipic Acid, Cotton Ginning, Alfafalfa Dehydrating, Malt Beverages, Ceramic Products Manufacturing, Electroplating, Wildfires And Prescribed Burning, Emissions From Soils-Greenhouse Gases, Termites-Greenhouse Gases, and Lightning Emissions-Greenhouse Gases.

  11. Water from air: An overlooked source of moisture in arid and semiarid regions

    USGS Publications Warehouse

    McHugh, Theresa; Morrissey, Ember M; Reed, Sasha C.; Hungate, Bruce A.; Schwartz, Egbert

    2015-01-01

    Water drives the functioning of Earth’s arid and semiarid lands. Drylands can obtain water from sources other than precipitation, yet little is known about how non-rainfall water inputs influence dryland communities and their activity. In particular, water vapor adsorption – movement of atmospheric water vapor into soil when soil air is drier than the overlying air – likely occurs often in drylands, yet its effects on ecosystem processes are not known. By adding 18O-enriched water vapor to the atmosphere of a closed system, we documented the conversion of water vapor to soil liquid water across a temperature range typical of arid ecosystems. This phenomenon rapidly increased soil moisture and stimulated microbial carbon (C) cycling, and the flux of water vapor to soil had a stronger impact than temperature on microbial activity. In a semiarid grassland, we also observed that non-rainfall water inputs stimulated microbial activity and C cycling. Together these data suggest that, during rain-free periods, atmospheric moisture in drylands may significantly contribute to variation in soil water content, thereby influencing ecosystem processes. The simple physical process of adsorption of water vapor to soil particles, forming liquid water, represents an overlooked but potentially important contributor to C cycling in drylands.

  12. Propane and butane emission sources to ambient air of Mexico City metropolitan area.

    PubMed

    Jaimes, L; Sandoval, J

    2002-04-22

    Samples of volatile organic compounds (VOCs) were collected in a smog chamber in order to determine whether automotive exhausts or LP Gas emissions play a greater role in the source of propane and butane, which affect ozone formation and other pollutants in the ambient air of the Mexico City metropolitan area (MCMA). These samples were collected in April 1995 during mornings and evenings. The testing methodology used for measuring exhaust emission were FTP or EPA-74 tests, and SHED type tests were also conducted in order to evaluate evaporative emissions. The finding from analysis of the VOCs collected in the morning demonstrate that in the atmosphere, propane concentrations are higher than that of butane but the reverse in evaporative and exhaust emissions, with the concentration of propane lower than that of butane. Our conclusion is that most of C3 and C4 in the ambient air comes from LP gas and not vehicle exhaust or evaporative emission, due to the higher levels of propane than butane in its formulation. The analysis of VOCs also indicates that although the conversion (in the smog chamber) of alkanes is low during the day, due to the high initial concentration, their contribution in the reaction mechanism to produce ozone can be appreciable.

  13. Controlling sources of indoor air pollution through pollution prevention. Report for January 1994--May 1998

    SciTech Connect

    Leovic, K.W.; Whitaker, D.; Brockmann, C.; Bayer, C.; Sojka, P.

    1998-12-31

    The paper is an overview of EPA research into controlling sources of indoor air pollution through pollution prevention (P2). The research focused on four approaches for P2: (1) developing methods and tools that can be used by others to evaluate emissions from equipment or products; (2) developing generic P2 solutions to IAQ problems; (3) identifying high-emitting raw materials or components of products; and (4) evaluating claimed low-emitting materials. Test method guidelines for measuring emissions from office equipment were developed and then evaluated by testing four dry-process copiers in one chamber and conducting a four-laboratory evaluation using one of the copiers. For aerosol consumer products, measurement methods and models were developed that can be used to better understand aerosol behavior so that more efficacious and less toxic products can be developed. As a generic solution for improved IAQ through P2, an innovative spray nozzle for use with precharged aerosol containers was developed and evaluated. The new design allows for the reformulation of selected aerosol consumer products using water and air in place of volatile organic compound solvents and hydrocarbon propellants, respectively.

  14. Development of a High Performance Air Source Heat Pump for the US Market

    SciTech Connect

    Abdelaziz, Omar; Shen, Bo; Gao, Zhiming; Baxter, Van D; Iu, Ipseng

    2011-01-01

    Heat pumps present a significant advantage over conventional residential heating technologies due to higher energy efficiencies and less dependence on imported oil. The US development of heat pumps dates back to the 1930 s with pilot units being commercially available in the 1950 s. Reliable and cost competitive units were available in the US market by the 1960 s. The 1973 oil embargo led to increased interest in heat pumps prompting significant research to improve performance, particularly for cold climate locations. Recent increasing concerns on building energy efficiency and environmental emissions have prompted a new wave of research in heat pump technology with special emphasis on reducing performance degradation at colder outdoor air temperatures. A summary of the advantages and limitations of several performance improvement options sought for the development of high performance air source heat pump systems for cold climate applications is the primary focus of this paper. Some recommendations for a high performance cold climate heat pump system design most suitable for the US market are presented.

  15. Water from air: an overlooked source of moisture in arid and semiarid regions.

    PubMed

    McHugh, Theresa A; Morrissey, Ember M; Reed, Sasha C; Hungate, Bruce A; Schwartz, Egbert

    2015-01-01

    Water drives the functioning of Earth's arid and semiarid lands. Drylands can obtain water from sources other than precipitation, yet little is known about how non-rainfall water inputs influence dryland communities and their activity. In particular, water vapor adsorption--movement of atmospheric water vapor into soil when soil air is drier than the overlying air--likely occurs often in drylands, yet its effects on ecosystem processes are not known. By adding (18)O-enriched water vapor to the atmosphere of a closed system, we documented the conversion of water vapor to soil liquid water across a temperature range typical of arid ecosystems. This phenomenon rapidly increased soil moisture and stimulated microbial carbon (C) cycling, and the flux of water vapor to soil had a stronger impact than temperature on microbial activity. In a semiarid grassland, we also observed that non-rainfall water inputs stimulated microbial activity and C cycling. Together these data suggest that, during rain-free periods, atmospheric moisture in drylands may significantly contribute to variation in soil water content, thereby influencing ecosystem processes. The simple physical process of adsorption of water vapor to soil particles, forming liquid water, represents an overlooked but potentially important contributor to C cycling in drylands. PMID:26345615

  16. Water from air: an overlooked source of moisture in arid and semiarid regions

    PubMed Central

    McHugh, Theresa A.; Morrissey, Ember M.; Reed, Sasha C.; Hungate, Bruce A.; Schwartz, Egbert

    2015-01-01

    Water drives the functioning of Earth’s arid and semiarid lands. Drylands can obtain water from sources other than precipitation, yet little is known about how non-rainfall water inputs influence dryland communities and their activity. In particular, water vapor adsorption – movement of atmospheric water vapor into soil when soil air is drier than the overlying air – likely occurs often in drylands, yet its effects on ecosystem processes are not known. By adding 18O-enriched water vapor to the atmosphere of a closed system, we documented the conversion of water vapor to soil liquid water across a temperature range typical of arid ecosystems. This phenomenon rapidly increased soil moisture and stimulated microbial carbon (C) cycling, and the flux of water vapor to soil had a stronger impact than temperature on microbial activity. In a semiarid grassland, we also observed that non-rainfall water inputs stimulated microbial activity and C cycling. Together these data suggest that, during rain-free periods, atmospheric moisture in drylands may significantly contribute to variation in soil water content, thereby influencing ecosystem processes. The simple physical process of adsorption of water vapor to soil particles, forming liquid water, represents an overlooked but potentially important contributor to C cycling in drylands. PMID:26345615

  17. [Levels and sources of gaseous polybrominated diphenyl ethers in air over the northern South China Sea].

    PubMed

    Li, Qi-lu; Li, Jun; Liu, Xiang; Xu, Wei-hai; Zhang, Gan

    2012-08-01

    A total of 32 air samples collected during a Shiyan III voyage over the northern South China Sea (SCS) were analyzed for polybrominated diphenyl ethers (PBDEs) by gas chromatography/mass spectrometry. The concentrations of sigma 7 PBDEs ranged from 0.07 to 35.9 pg x m(-3). The sigma 7 PBDEs were dominated by tetra-(BDE-47) and penta-(BDE-99 and -100) components, which accounted for 51.5% and 36.9%, respectively. This result indicated that the widely used commercial penta-BDE product was the original source. The higher concentrations of PBDEs were monitored close to the coastline of the South China and Philippine, while the lower concentrations were found over the SCS adjacent to central coast of Vietnam. Back trajectory analysis showed that the high PBDE concentrations observed in air over the northern SCS may be related to the continental pollutant outflows from the southeast coast of China, especially the Pearl River Delta, Taiwan and Philippine, by prevailing northeast wind transport.

  18. Air-kerma strength determination of a new directional {sup 103}Pd source

    SciTech Connect

    Aima, Manik Reed, Joshua L.; DeWerd, Larry A.; Culberson, Wesley S.

    2015-12-15

    Purpose: A new directional {sup 103}Pd planar source array called a CivaSheet™ has been developed by CivaTech Oncology, Inc., for potential use in low-dose-rate (LDR) brachytherapy treatments. The array consists of multiple individual polymer capsules called CivaDots, containing {sup 103}Pd and a gold shield that attenuates the radiation on one side, thus defining a hot and cold side. This novel source requires new methods to establish a source strength metric. The presence of gold material in such close proximity to the active {sup 103}Pd region causes the source spectrum to be significantly different than the energy spectra of seeds normally used in LDR brachytherapy treatments. In this investigation, the authors perform air-kerma strength (S{sub K}) measurements, develop new correction factors for these measurements based on an experimentally verified energy spectrum, and test the robustness of transferring S{sub K} to a well-type ionization chamber. Methods: S{sub K} measurements were performed with the variable-aperture free-air chamber (VAFAC) at the University of Wisconsin Medical Radiation Research Center. Subsequent measurements were then performed in a well-type ionization chamber. To realize the quantity S{sub K} from a directional source with gold material present, new methods and correction factors were considered. Updated correction factors were calculated using the MCNP 6 Monte Carlo code in order to determine S{sub K} with the presence of gold fluorescent energy lines. In addition to S{sub K} measurements, a low-energy high-purity germanium (HPGe) detector was used to experimentally verify the calculated spectrum, a sodium iodide (NaI) scintillating counter was used to verify the azimuthal and polar anisotropy, and a well-type ionization chamber was used to test the feasibility of disseminating S{sub K} values for a directional source within a cylindrically symmetric measurement volume. Results: The UW VAFAC was successfully used to measure the S

  19. Source apportionment of polychlorinated biphenyls in Chicago air from 1996 to 2007.

    PubMed

    Rodenburg, Lisa A; Meng, Qingyu

    2013-04-16

    While the overall atmospheric polychlorinated biphenyl (PCB) levels in many urban areas are declining, it is not clear whether this decline is due to control strategies or merely due to natural attenuation. To investigate this issue, Positive Matrix Factorization (PMF) was used to identify the dominant sources of gas-phase PCBs in the atmosphere of Chicago, IL using a data set collected from 1996 to 2007 by the Integrated Atmospheric Deposition Network (IADN). Both the older PMF2 software and the newer EPA-sponsored PMF 3.0 software were employed. Both models resolved 5 factors, but they yielded somewhat different results in terms of the congener patterns of the factors and their temporal variation. The PMF2 software resolved factors that better resembled the original Aroclor formulations. While it is possible to apply an exponential decay model to this data set and derive statistically significant rate constants that indicate that ΣPCBs and some of the resolved factors are declining in Chicago air, examining plots of the 365-day moving average concentrations shows that they do not decrease in a fashion consistent with exponential decay. Instead, they display periods of decline as well as periods of increase. Thus an exponential decay model is not appropriate, and long-term time trends identified from this 12-year data set cannot be used to predict the future trends in PCB concentrations in the air of Chicago. Two of the five resolved factors resemble low MW Aroclors, and declined from 1996 to 2007. The other three factors, which represent the majority of the mass in the data set, are either not declining or actually increasing over time. Thus past efforts to eliminate PCBs from the Great Lakes ecosystem have been only marginally effective, if at all. Additional effort is needed to identify and eliminate atmospheric PCB sources in Chicago.

  20. A gasdynamic gun driven by gaseous detonation.

    PubMed

    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. PMID:26827358

  1. A gasdynamic gun driven by gaseous detonation.

    PubMed

    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.

  2. 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.

  3. Effects of a gun dealer's change in sales practices on the supply of guns to criminals.

    PubMed

    Webster, Daniel W; Vernick, Jon S; Bulzacchelli, Maria T

    2006-09-01

    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.

  4. 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

  5. Ballistics of space launch by a rail gun

    NASA Astrophysics Data System (ADS)

    Panin, Alexander

    2010-10-01

    The idea of using a big gun to launch objects to space has been around for years -- even Isaac Newton considered the concept. However the technology of accelerating a payload with a gun only recently began approaching orbital velocity (8 km/sec). NASA is currently experimenting with a rail gun which utilizes a magnetic field powered by electricity to accelerate a projectile along a set of rails, similar to train rails. Velocities up to 3 km/sec have been reported for small projectiles, and it seems that orbital velocities can soon become a reality too. We model a launch of various projectiles from Earth surface into the elevation corresponding to the low Earth orbit (about 200-250 km above Earth's surface). The goal of this modeling is to study feasibility of such launch (and accelerations induced), and the ballistics of the flight via Earth's atmosphere (the trajectory, air drag induced, pressure and temperature generated by air drag, etc) and thus the requirements for a mass, size, strength, heat shield, and general design of a payload capsule.

  6. An investigation of the source of air Ar contamination in KAr dating

    USGS Publications Warehouse

    Mussett, A.E.; Brent, Dalrymple G.

    1968-01-01

    Precision of young KAr ages is limited by air argon contamination. A series of experiments in which the exposure of basalt and sanidine samples to air argon was controlled, shows that most of the air contamination does not arise in the laboratory. Because of this, it seems unlikely that air argon contamination can be significantly reduced by special sample handling and preparation techniques. ?? 1968.

  7. Location of and landing on a source of human body odour by female Culex quinquefasciatus in still and moving air

    PubMed Central

    LACEY, EMERSON S.; CARDÉ, RING T.

    2014-01-01

    The orientation to and landing on a source of human odour by female Culex quinquefasciatus Say (Diptera: Culicidae) is observed in a wind tunnel without an airflow or with a laminar airflow of 0.2 m s-1. Odours from human feet are collected by ‘wearing’ clean glass beads inside a stocking and presenting beads in a Petri dish in a wind tunnel. Mosquitoes are activated by brief exposure to a 1 L min-1 jet of 4% CO2 positioned 10 cm from the release cage. In moving air at 0.2 m s-1, a mean of 3.45 ± 0.49 landings are observed in 10 min trials (5 mosquitoes per trial), whereas 6.50 ± 0.96 landings are recorded in still air. Furthermore, 1.45 ± 0.31mosquitoes are recorded on beads at any one time in moving air (a measure of individuals landing versus one landing multiple times) compared to 3.10 ± 0.31 in still air. Upwind flight to beads in moving air is demonstrated by angular headings of flight immediately prior to landing, whereas approaches to beads in still air are oriented randomly. The mean latency until first landing is 226.7 ± 17.98 s in moving air compared to 122.5 ± 24.18 in still air. Strategies used to locate a prospective host at close range in still air are considered. PMID:26472918

  8. An ultrafast nanotip electron gun triggered by grating-coupled surface plasmons

    NASA Astrophysics Data System (ADS)

    Schröder, Benjamin; Sivis, Murat; Bormann, Reiner; Schäfer, Sascha; Ropers, Claus

    2015-12-01

    We demonstrate multiphoton photoelectron emission from gold nanotips induced by nanofocusing surface plasmons, resonantly excited on the tip shaft by a grating coupler. The tip is integrated into an electron gun assembly, which facilitates control over the spatial emission sites and allows us to disentangle direct grating emission from plasmon-triggered apex emission. The nanoscale source size of this electron gun concept enables highly coherent electron pulses with applications in ultrafast electron imaging and diffraction.

  9. An ultrafast nanotip electron gun triggered by grating-coupled surface plasmons

    SciTech Connect

    Schröder, Benjamin; Sivis, Murat; Bormann, Reiner; Schäfer, Sascha; Ropers, Claus

    2015-12-07

    We demonstrate multiphoton photoelectron emission from gold nanotips induced by nanofocusing surface plasmons, resonantly excited on the tip shaft by a grating coupler. The tip is integrated into an electron gun assembly, which facilitates control over the spatial emission sites and allows us to disentangle direct grating emission from plasmon-triggered apex emission. The nanoscale source size of this electron gun concept enables highly coherent electron pulses with applications in ultrafast electron imaging and diffraction.

  10. A review of biomarker compounds as source indicators and tracers for air pollution.

    PubMed

    Simoneit, B R

    1999-01-01

    An overview of the application of organic geochemistry to the analysis of organic matter on aerosol particles is presented here. This organic matter is analyzed as solvent extractable bitumen/ lipids by gas chromatography-mass spectrometry. The organic geochemical approach assesses the origin, the environmental history and the nature of secondary products of organic matter by using the data derived from specific molecular analyses. Evaluations of production and fluxes, with cross-correlations can thus be made by the application of the same separation and analytical procedures to samples from point source emissions and the ambient atmosphere. This will be illustrated here with typical examples from the ambient atmosphere (aerosol particles) and from emissions of biomass burning (smoke). Organic matter in aerosols is derived from two major sources and is admixed depending on the geographic relief of the air shed. These sources are biogenic detritus (e.g., plant wax, microbes, etc.) and anthropogenic particle emissions (e.g., oils, soot, synthetics, etc.). Both biogenic detritus and some of the anthropogenic particle emissions contain organic materials which have unique and distinguishable compound distribution patterns (C(14)-C(40)). Microbial and vascular plant lipids are the dominant biogenic residues and petroleum hydrocarbons, with lesser amounts of the pyrogenic polynuclear aromatic hydrocarbons (PAH) and synthetics (e.g., chlorinated compounds), are the major anthropogenic residues. Biomass combustion is another important primary source of particles injected into the global atmosphere. It contributes many trace substances which are reactants in atmospheric chemistry and soot paniculate matter with adsorbed biomarker compounds, most of which are unknown chemical structures. The injection of natural product organic compounds into smoke occurs primarily by direct volatilization/steam stripping and by thermal alteration based on combustion temperature. Although the

  11. A review of biomarker compounds as source indicators and tracers for air pollution.

    PubMed

    Simoneit, B R

    1999-01-01

    An overview of the application of organic geochemistry to the analysis of organic matter on aerosol particles is presented here. This organic matter is analyzed as solvent extractable bitumen/ lipids by gas chromatography-mass spectrometry. The organic geochemical approach assesses the origin, the environmental history and the nature of secondary products of organic matter by using the data derived from specific molecular analyses. Evaluations of production and fluxes, with cross-correlations can thus be made by the application of the same separation and analytical procedures to samples from point source emissions and the ambient atmosphere. This will be illustrated here with typical examples from the ambient atmosphere (aerosol particles) and from emissions of biomass burning (smoke). Organic matter in aerosols is derived from two major sources and is admixed depending on the geographic relief of the air shed. These sources are biogenic detritus (e.g., plant wax, microbes, etc.) and anthropogenic particle emissions (e.g., oils, soot, synthetics, etc.). Both biogenic detritus and some of the anthropogenic particle emissions contain organic materials which have unique and distinguishable compound distribution patterns (C(14)-C(40)). Microbial and vascular plant lipids are the dominant biogenic residues and petroleum hydrocarbons, with lesser amounts of the pyrogenic polynuclear aromatic hydrocarbons (PAH) and synthetics (e.g., chlorinated compounds), are the major anthropogenic residues. Biomass combustion is another important primary source of particles injected into the global atmosphere. It contributes many trace substances which are reactants in atmospheric chemistry and soot paniculate matter with adsorbed biomarker compounds, most of which are unknown chemical structures. The injection of natural product organic compounds into smoke occurs primarily by direct volatilization/steam stripping and by thermal alteration based on combustion temperature. Although the

  12. D Phase Space Measurements at the SLAC Gun Test Facility

    NASA Astrophysics Data System (ADS)

    Schmerge, J. F.; Bolton, P. R.; Clendenin, J. E.; Dowell, D. H.; Gierman, S. M.; Limborg, C. G.; Murphy, B. F.

    2003-12-01

    Proposed fourth generation light sources using SASE FELs to generate short pulse, coherent, X-rays require demonstration of high brightness electron sources. The Gun Test Facility (GTF) at SLAC was built to test high brightness sources for the proposed Linac Coherent Light Source at SLAC. The GTF is composed of an S-band photocathode rf gun with a Cu cathode, emittance compensating solenoid, single 3 m SLAC linac section and e-beam diagnostic section with a UV drive laser system. The longitudinal emittance exiting the gun has been determined by measuring the energy spectrum downstream of the linac as a function of the linac phase. The e-beam pulse width, correlated and uncorrelated energy spread at the linac entrance have been fit to the measured energy spectra using a least square error fitting routine. The fit yields a pulse width of 2.9 ps FWHM for a 4.3 ps FWHM laser pulsewidth and 2% rms correlated energy spread with 0.07% rms uncorrelated energy spread. The correlated energy spread is enhanced in the linac to allow slice emittance measurements by conducting a quadrupole scan in a dispersive section. The normalized slice emittance has been measured to be as low as 2 mm-mrad for beams with peak currents up to 150 A (300 pC with a laser pulse length of 1.8 ps) while the full projected emittance is 3 mm-mrad.

  13. Indoor air pollution: Sources and control. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    Not Available

    1994-01-01

    The bibliography contains citations concerning indoor air pollution in residential, commercial, industrial, and institutional buildings. Indoor air quality assessment, health hazard evaluation, and contaminant identification and measurement are discussed. Indoor air pollution control methods and equipment are evaluated. Air quality analyses of energy efficient buildings are presented. Indoor air pollution from radon and asbestos are discussed in other bibliographies. (Contains 250 citations and includes a subject term index and title list.)

  14. Indoor air pollution: Sources and control. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1998-02-01

    The bibliography contains citations concerning indoor air pollution in residential, commercial, industrial, and institutional buildings. Indoor air quality assessment, health hazard evaluation, and contaminant identification and measurement are discussed. Indoor air pollution control methods and equipment are evaluated. Air quality analyses of energy efficient buildings are presented. Indoor air pollution from radon and asbestos are discussed in other bibliographies. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  15. Indoor air pollution: Sources and control. (Latest citations from the NTIS Bibliographic database). NewSearch

    SciTech Connect

    Not Available

    1994-11-01

    The bibliography contains citations concerning indoor air pollution in residential, commercial, industrial, and institutional buildings. Indoor air quality assessment, health hazard evaluation, and contaminant identification and measurement are discussed. Indoor air pollution control methods and equipment are evaluated. Air quality analyses of energy efficient buildings are presented. Indoor air pollution from radon and asbestos are discussed in other bibliographies. (Contains 250 citations and includes a subject term index and title list.)

  16. Indoor air pollution: Sources and control. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1996-12-01

    The bibliography contains citations concerning indoor air pollution in residential, commercial, industrial, and institutional buildings. Indoor air quality assessment, health hazard evaluation, and contaminant identification and measurement are discussed. Indoor air pollution control methods and equipment are evaluated. Air quality analyses of energy efficient buildings are presented. Indoor air pollution from radon and asbestos are discussed in other bibliographies.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  17. Indoor air pollution: Sources and control. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1995-10-01

    The bibliography contains citations concerning indoor air pollution in residential, commercial, industrial, and institutional buildings. Indoor air quality assessment, health hazard evaluation, and contaminant identification and measurement are discussed. Indoor air pollution control methods and equipment are evaluated. Air quality analyses of energy efficient buildings are presented. Indoor air pollution from radon and asbestos are discussed in other bibliographies.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  18. Have guns, will travel

    SciTech Connect

    Khripunov, I.

    1997-05-01

    In the latter decades of the Cold War, defense industries were at the heart of the Soviet economy, absorbing one-third of the country`s industrial force; 60 percent of the machine-building industry; 80 percent of all research and development personnel; and 20 percent of Soviet energy output. Today, the Russian defense economy is near collapse. In 1996, Russia`s air force could not buy a single combat plane. President Boris Yeltsin admitted in his State of the Union address on March 6 that {open_quotes}the Russian armed forces are five to 10 years, sometimes 15 years, behind the world`s most powerful armies in the general level of {open_quote}technical equipment.{close_quote}{close_quotes} The only {open_quotes}bright{close_quotes} spot in the Russian military-industrial complex-the arms trade. Russia is desperately pushing weapons in the international market in an attempt to salvage its defense industrial base. Russia`s enormous arms complex includes about 2,000 enterprises directly engaged in military production, a host of subcontractors, 920 research organizations, and a work force of roughly 5 million.

  19. Note: O-ring stack system for electron gun alignment.

    PubMed

    Park, In-Yong; Cho, Boklae; Han, Cheolsu; Shin, Seungmin; Lee, Dongjun; Ahn, Sang Jung

    2015-01-01

    We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignment and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications. PMID:25638137

  20. Note: O-ring stack system for electron gun alignment

    NASA Astrophysics Data System (ADS)

    Park, In-Yong; Cho, Boklae; Han, Cheolsu; Shin, Seungmin; Lee, Dongjun; Ahn, Sang Jung

    2015-01-01

    We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignment and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications.