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Sample records for cement gun pressurization

  1. Characterization of a Dielectric Barrier Plasma Gun Discharging at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guang-Qiu; GE Yuan-Jing; ZHANG Yue-Fei; CHEN Guang-Liang

    2004-01-01

    @@ We develop a plasma gun based on dielectric barrier discharge and working at atmospheric pressure. A theoretical model to predict the gun discharge voltage is built, which is in agreement with the experimental results. After investigating the characterization of discharging gun and utilizing it for polymerization, we find that the gun can be used as a source to generate a stable uniform plasma for different plasma-processing technologies.

  2. Internal ballistics of recoilless high-low pressure guns using hepta-tubular powders

    Directory of Open Access Journals (Sweden)

    M. C. Gupta

    1960-04-01

    Full Text Available In this paper, the theory of recoilless high-low pressure guns has been discussed by taking the form function and the results have been applied to the case of hepta-tubular powders. The results for high-low pressure guns follow as a particular case.

  3. The performance of three vacuum-mixing cement guns – a comparison of the fatigue properties of Simplex P cement

    OpenAIRE

    Yau, W.; Ng, T.; Chiu, K.; Poon, K.; Ho, W.; Luk, D.

    2001-01-01

    We tested three commercially available cement-mixing systems (Howmedica, Summit and Stryker). After mixing the cement was allowed to cure in metal moulds under standard conditions. Sixty-nine cement blocks were produced. The fatigue behavior of the blocks was tested until failure. A wide scattering of results was observed in all the three systems. Uneven mixing of the polymer and monomer was observed in the Howmedica system. A significantly stronger cement (P=0.018) was produced with the Stry...

  4. Impact of pressure on Sintering of Cemented Carbides

    OpenAIRE

    Owais, Tariq Muhammad

    2013-01-01

    In this Master Thesis work, the effect of pressure on sintering of cemented carbides is investigated. Special focus hasbeen given to the residual porosity after sintering. It is well known that sintering shrinkage depends on binder phasecontent, grain size, temperature and pressure. Thus 4 different cemented carbides grades were selected. The gradeswere pressed into standard products and TRS (Tensile Rupture Strength) rods with two different shrinkage factors.These were then sintered at diffe...

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Shuang; Wang, Kaile; Zuo, Shasha; Liu, Jiahui [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhang, Jue, E-mail: zhangjue@pku.edu.cn; Fang, Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)

    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.

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

    Science.gov (United States)

    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.

  8. On Attainment of Constant Pressure Phase in an Orthodox Gun with Resistance

    Directory of Open Access Journals (Sweden)

    R. N. Bhattacharyya

    1976-07-01

    Full Text Available In this paper the conditions for the existence pressure phase for certain period during burning in an orthodox gun with constant bore resistance have been obtained and then the internal ballistics is calculated.

  9. The internal ballistics of a high: low pressure gun

    Directory of Open Access Journals (Sweden)

    J. N. Kapur

    1957-04-01

    Full Text Available In the present paper the system of equations for the Non-Isothermal Model for a H/L gun has been developed and from this, the systems of equations for Isothermal and Non-isothermal models for orthodox gun and solid fuel rockets have been deduced. The Non-Isothermal Model for H/L gun has been integrated for a tubular charge. For isothermal model, reduction to an equivalent non-leaking problem has been discussed and the partially non-isothermal model has been integrated for the linear law. After all-burnt modification needed in Corner's energy equation is obtained.

  10. On Ballistics Solution of HL Pressure Gun for Composite Charges Taking Most General Form Function

    Directory of Open Access Journals (Sweden)

    Padam Chand Gupta

    1977-01-01

    Full Text Available The present paper gives the solution of the equation of internal ballistics of H/L gun for composite charges taking most general form function assuming constant pressure in both the chambers during the second stage of burning, i.e., after the burning of the first component charge.

  11. The Novel Method to Estimate Effect of Cement Slurry Consistency toward Friction Pressure in Oil/Gas Well Cementing

    Directory of Open Access Journals (Sweden)

    Adrian Pattinasarany

    2012-11-01

    Full Text Available The aim of this study is to investigate effect of cement slurry consistency toward friction pressure during oil/gas cementing operation. Completion of an oil/gas well has become more important because the reserve has become harder to find. The oil/gas company cannot afford to lose million dollars they spent when locating, drilling and recovering the oil from the Earth if they failed it. The safety, health and environment also have become more important issue, because any completion problem can lead to prolong operation and creating more hazard and risk. Cementing operation plays a very important role during completion because it creates a secure conduit to bring the precious oil/gas to the surface and a place to install completion jewelry. During cementing operation lost circulation can be one of the serious problems that arise. Circulation is said to be lost when the cement slurry pumped flows into one or more geological formations instead of returning up casing annulus. This is due to sum of hydrostatic pressure and friction pressure is exceeding fracture gradient. Method that commonly used to calculate friction from American Petroleum Institute (API assumed the cement slurry will exhibit time independent nature. Cement slurry consistency was found to have significant effect to friction pressure.

  12. Pressure cycling induced modification of a cemented carbide

    International Nuclear Information System (INIS)

    The wear of cemented carbide rock drill buttons is due to a complex mixture of mechanisms. One important of such mechanism is the surface fatigue that occurs due to the percussive conditions of rock drilling. To isolate the effects of this mechanism, a mechanical pressure cycling test has been performed on a cemented carbide with 11 % Co and 2 μm WC grain size. The test was ended after 60000 pressure cycles. No signs of fatigue crack nucleation were found. The changes in hardness, fracture toughness, erosion resistance, magnetical coercivity and thermal shock resistance were measured. The microstructure of the sample was investigated with x-ray diffraction, plus scanning and transmission electron microscopy. The fracture toughness decreased 14 % due to the pressure cycling while the hardness did not change. In addition, the thermal shock resistance and the erosion resistance decreased. The magnetical coercivity increased 90 % indicating significant phase transformations or high defect density in the Co binder phase. The TEM revealed no deformation of the WC phase, but important alterations of the Co phase. The Co phase was transformed from fcc into a new unidentified phase, characterized by atomic inter planar distance present in fcc and hcp plus an unfamiliar distance of 2.35 Aa. This phase is suggested to be due to a more complex stacking sequence of the close-packed planes than in hcp or fcc. (author)

  13. Modified femoral pressuriser generates a longer lasting high pressure during cement pressurisation

    Directory of Open Access Journals (Sweden)

    Kjellson Fred

    2011-10-01

    Full Text Available Abstract Background The strength of the cement-bone interface in hip arthroplasty is strongly related to cement penetration into the bone. A modified femoral pressuriser has been investigated, designed for closer fitting into the femoral opening to generate higher and more constant cement pressure compared to a commercial (conventional design. Methods Femoral cementation was performed in 10 Sawbones® models, five using the modified pressuriser and five using a current commercial pressuriser as a control. Pressure during the cementation was recorded at the proximal and distal regions of the femoral implant. The peak pressure and the pressure-time curves were analysed by student's t-test and Two way ANOVA. Results The modified pressuriser showed significantly and substantially longer durations at higher cementation pressures and slightly, although not statistically, higher peak pressures compared to the conventional pressuriser. The modified pressuriser also produced more controlled cement leakage. Conclusion The modified pressuriser generates longer higher pressure durations in the femoral model. This design modification may enhance cement penetration into cancellous bone and could improve femoral cementation.

  14. Pneumatic colon injury following high pressure blow gun dust cleaner spray to the perineum

    OpenAIRE

    Sy, Edgar D.; Chiu, Yin-I.; Shan, Yan-Shen; Ong, Roger L.

    2014-01-01

    Introduction A pneumatic tool or air tool such as blow gun dust cleaner is a tool driven by compressed air and spraying of the perineum can insufflate the colon due to its high pressure and high flow rate. Presentation of case We present a case of 4 year old boy who developed sudden onset of tense abdominal distention and developed peritonitis. Patient’s family initially denied a history of trauma. Radiologic examination showed pneumoperitoneum and colon dilatation. Exploratory laparotomy rev...

  15. Geophysical investigation of the pressure field produced by water guns at a pond site in La Crosse, Wisconsin

    Science.gov (United States)

    Adams, Ryan F.; Morrow, William S.

    2015-01-01

    Three different geophysical sensor types were used to characterize the underwater pressure waves generated by the underwater firing of a seismic water gun and their suitability for establishing a pressure barrier to potentially direct or prevent the movement of the Asian carps. The sensors used to collect the seismic information were blast rated hydrophones and underwater blast sensors. Specific location information for the water guns and the sensors was obtained using either laser rangefinders or differentially corrected global positioning systems (GPS).

  16. Locked-in syndrome caused by the pressure exerted by the sound gun

    Directory of Open Access Journals (Sweden)

    Ayse Belin Ozer

    2014-01-01

    Full Text Available A 19-year-old male patient who wounded himself with a gun in the cranial region had a Glasgow coma scale of 3E. At posttraumatic day 7, locked-in syndrome was considered upon detection of vertical eye movements, meaningful winks, and quadriplegia. Apart from the classical view, computed tomography (CT and postmortem examination of the brain showed an infarct area in the cerebellum. However, vertebrobasilar artery system was normal. In this case report, we would like to present that unlike cases with ischemia, specific CT findings may not be evident in posttraumatic cases and ischemia may occur in the cerebellum as a result of the pressure exerted by a sound gun.

  17. Foamed cement for squeeze cementing low-pressure, highly permeable reservoirs

    International Nuclear Information System (INIS)

    Four different cement squeezing techniques have been used on wells producing from the Keg River formation in the Rainbow Lake area of Alberta, Canada. This paper evaluates 151 cement squeeze treatments performed at 96 wellsites and compares the use of foam cement vs. conventional squeeze treatments and techniques. Discussion includes key aspects, such as candidate selection, slurry design, treatment design, economic evaluation, and operational considerations

  18. Discrete element modeling of cemented sand and particle crushing at high pressures

    OpenAIRE

    de Bono, John Patrick

    2013-01-01

    This project aims to provide an insight into the behaviour of cemented sand under high pressures, and to further the understanding of the role of particle crushing. The discrete element method is used to investigate the micro mechanics of sand and cemented sand in high-pressure triaxial tests and one-dimensional normal compression. Using the software PFC3D, a new triaxial model has been developed, which features an effective flexible membrane that allows free deformation of the specimen ...

  19. Characterization of pulsed atmospheric-pressure plasma streams (PAPS) generated by a plasma gun

    International Nuclear Information System (INIS)

    An experimental study of atmospheric-pressure rare gas plasma propagation in a high-aspect-ratio capillary is reported. The plasma is generated with a plasma gun device based on a dielectric barrier discharge (DBD) reactor powered by either nanosecond or microsecond rise-time high-voltage pulses at single-shot to multi-kHz frequencies. The influence of the voltage waveform, pulse polarity, pulse repetition rate and capillary material have been studied using nanosecond intensified charge-coupled device imaging and plasma-front velocity measurements. The evolution of the plasma appearance during its propagation and the study of the role of the different experimental parameters lead us to suggest a new denomination of pulsed atmospheric-pressure plasma streams to describe all the plasma features, including the previously so-called plasma bullet. The unique properties of such non-thermal plasma launching in capillaries, far from the primary DBD plasma, are associated with a fast ionization wave travelling with velocity in the 107–108 cm s−1 range. Voltage pulse tailoring is shown to allow for a significant improvement of such plasma delivery. Thus, the plasma gun device affords unique opportunities in biomedical endoscopic applications. (paper)

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

    Science.gov (United States)

    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.

  1. Effect of Admixtures on the Yield Stresses of Cement Pastes under High Hydrostatic Pressures

    Directory of Open Access Journals (Sweden)

    Hong Jae Yim

    2016-03-01

    Full Text Available When cement-based materials are transported at a construction site, they undergo high pressures during the pumping process. The rheological properties of the materials under such high pressures are unknown, and estimating the workability of the materials after pumping is a complex problem. Among various influential factors on the rheology of concrete, this study investigated the effect of mineral and chemical admixtures on the high-pressure rheology. A rheometer was fabricated that could measure the rheological properties while maintaining a high pressure to simulate the pumping process. The effects of superplasticizer, silica fume, nanoclay, fly ash, or ground granulated blast furnace slag were investigated when mixed with two control cement pastes. The water-to-cement ratios were 0.35 and 0.50.

  2. Undrained heating and anomalous pore-fluid pressurization of a hardened cement paste

    Science.gov (United States)

    Ghabezloo, S.; Sulem, J.; Saint-Marc, J.

    2009-04-01

    Temperature increase in a fluid-saturated porous material in undrained condition leads to volume change and pore pressure increase due to the discrepancy between the thermal expansion coefficients of the pore fluid and of the pore volume. This increase of the pore fluid pressure induces a reduction of the effective mean stress, and can lead to shear failure or hydraulic fracturing. This phenomenon is important is important in environmental engineering for radioactive (exothermal) waste disposal in deep clay geological formations as well as in geophysics in the studies of rapid fault slip events when shear heating tends to increase the pore pressure and to decrease the effective compressive stress and the shearing resistance of the fault material (Sulem et al. 2007). This is also important in petroleum engineering where the reservoir rock and the well cement lining undergo sudden temperature changes for example when extracting heavy oils by steam injection methods. This rapid increase of temperature could damage cement sheath integrity of wells and lead to loss of zonal isolation. The values of the thermal pressurization coefficient, defined as the pore pressure increase due to a unit temperature increase in undrained condition, is largely dependent upon the nature of the material, the state of stress, the range of temperature change, the induced damage. The large variability of the thermal pressurization coefficient reported in the literature for different porous materials with values from 0.01MPa/°C to 1.5MPa/°C highlights the necessity of laboratory studies. This phenomenon of thermal pressurization is studied experimentally for a fluid-saturated hardened cement paste in an undrained heating test. Careful analysis of the effect of the dead volume of the drainage system of the triaxial cell has been performed based on a simple correction method proposed by Ghabezloo and Sulem (2008, 2009). The drained and undrained thermal expansion coefficients of the hardened

  3. A Note on the Constant Pressure Phase in an Orthodox Gun with Moderated Charges using Hydro-Dynamical Model

    Directory of Open Access Journals (Sweden)

    D. K. Narvilkar

    1988-01-01

    Full Text Available The existing work on the constant pressure guns has been improved upon by introducing the concept of Lagrange mean density function for the propellant gases behind the shot. Lagrange hydrodynamical model has been considered and the expressions have been established to work out the shape factor of the second component of the moderated charge, which will maintain a constant pressure during the burning of this component. This is followed by the numerical computations of a problem to establish the physical interpretation of the results.

  4. Deposition of SiOx on Metal Surface with a DBD Plasma Gun at Atmospheric Pressure for Corrosion Prevention

    Institute of Scientific and Technical Information of China (English)

    HAN Erli; CHEN Qiang; ZHANG Yuefei; CHEN Fei; GE Yuanjing

    2007-01-01

    In this study,SiOx films were deposited by a dielectric barrier discharge(DBD)plasma gun at an atmospheric pressure.The relationship of the film structures with plasma powers Was investigated by Fourier transform infrared spectroscopy(FTIR),and scanning electron microscope(SEM).It was shown that an uniform and cross-linking structure film was formed by the DBD gun.As an application,the SiOx films were deposited on a carbon steel surface for the anti-corrosion purpose.The experiment was carried out in a 0.1 M NaC1 solution.It Was found that a very good anti-corrosive property was obtained,i.e.,the corrosion rate Was decreased c.a.15 times in 5% NaC1 solution compared to the non-SiOx coated steel,as detected by the potentiodynamic polarization measurement.

  5. Gun Play

    Science.gov (United States)

    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…

  6. GUNS BEFORE POLITICS

    OpenAIRE

    P.L. Moorcroft

    2012-01-01

    'What we must stop is a situation where the gun is a means of promotion, a machine gun a way of applying pressure, a tank becomes government policy.' This was the despairing cry of an African lawyer during yet another recent military intervention in that most coup-ridden of African states, Dahomey.

  7. GUNS BEFORE POLITICS

    Directory of Open Access Journals (Sweden)

    P.L. Moorcroft

    2012-02-01

    Full Text Available 'What we must stop is a situation where the gun is a means of promotion, a machine gun a way of applying pressure, a tank becomes government policy.' This was the despairing cry of an African lawyer during yet another recent military intervention in that most coup-ridden of African states, Dahomey.

  8. Rheological and Adhesive Behavior of Gunning Mix for Blast Furnace Repair

    Institute of Scientific and Technical Information of China (English)

    CAO Feng; LONG Shigang; WU Xingrong; SUN Jialin; HONG Yanruo

    2003-01-01

    The aim of this experimental work was to investigate the rheological and adhesive performance of gunning mix suspensions. The results of rheological tests indicate that:the rheological curve of gunning mix bonded by high-alumina cement (HACG) is Bingham type; the rheological curve of low cement gunning mix (LCG) bonded by microsilica is characterized by pseudo-plasticity fluid with yielding stress; and the rheological property of low-cement gunning mix bonded by microsilica is proved to be better than that of gunning mix bonded by cement. Meanwhile as indicated by the adhesive tests: the better the rheological properties of gunning mix suspension, the better the repair effect would be.

  9. Experimental Evaluation of Permeability in Wellbore Cements under Elevated Temperatue, Pressure and Salinity Using a Liquid Pressure-Pulse Decay Permeameter

    Science.gov (United States)

    Bello, K.; Radonjic, M.

    2013-12-01

    Kolawole Bello (kbello1@tigers.lsu.edu) and Mileva Radonjic (mileva@lsu.edu), Craft and Hawkins Department of Petroleum Engineering, 2131 Patrick F. Taylor Hall, Louisiana State University, Baton Rouge, LA 70803 Geopressured reservoirs in the northern Gulf of Mexico basin along the coast of Louisiana have been determined to be viable source of geothermal energy and also for carbon sequestration. These reservoirs are made of unconsolidated sandstone capped by shale layers and possess temperatures as high as 140°C. In addition, high salinities of 100 g/L are associated with these reservoirs due to the dissolution of surrounding salt domes. In production of geothermal reservoir, cementing cost accounts for 50% of total costs unlike in oil and gas wells where cementing cost is approximately 15%. This difference in cost is caused by the difference in fluid chemistry. In this project, we propose in-situ harvesting of heat energy resulting in differential temperature across the cement. As a result of thermal loading, hydrated cement fractures. In addition, leaching occurs in wellbore cements when exposed to pH less than 13 causing an increase in permeability. This consequently leads to lack of zonal isolation and compromises the mechanical integrity of the cement. This study provides ways of evaluating wellbore cements under conditions experienced in geopressured reservoirs. For the first time, we have state of the art equipment capable of measuring brine permeability of cement using Liquid Pressure-pulse Decay Permeameter (PDPL). Under in-situ confining pressure, brine permeability is more accurate than gas permeability due to the decrease in pore throat diameter. PDPL provides an efficient and accurate way of measuring brine permeability in low permeability materials at reservoir temperature and pressure. This permeability is function of pressure decay over time. Permeability measurements were taken before and after cyclic thermal loading of cement cores at

  10. Experimental determination of carbonation rate in Portland cement at 25°C and relatively high CO2 partial pressure

    Science.gov (United States)

    Hernández-Rodríguez, Ana; Montegrossi, Giordano; Huet, Bruno; Virgili, Giorgio; Orlando, Andrea; Vaselli, Orlando; Marini, Luigi

    2016-04-01

    The aim of this work is to study the alteration of Portland class G Cement at ambient temperature under a relatively high CO2 partial pressure through suitably designed laboratory experiments, in which cement hydration and carbonation are taken into account separately. First, the hydration process was carried out for 28 days to identify and quantify the hydrated solid phases formed. After the completion of hydration, accompanied by partial carbonation under atmospheric conditions, the carbonation process was investigated in a stirred micro-reactor (Parr instrument) with crushed cement samples under 10 bar or more of pure CO2(g) and MilliQ water adopting different reaction times. The reaction time was varied to constrain the reaction kinetics of the carbonation process and to investigate the evolution of secondary solid phases. Chemical and mineralogical analyses (calcimetry, chemical composition, SEM and X-ray Powder Diffraction) were carried out to characterize the secondary minerals formed during cement hydration and carbonation. Water analyses were also performed at the end of each experimental run to measure the concentrations of relevant solutes. The specific surface area of hydrated cement was measured by means of the BET method to obtain the rates of cement carbonation. Experimental outcomes were simulated by means of the PhreeqC software package. The obtained results are of interest to understand the comparatively fast cement alteration in CO2 production wells with damaged casing.

  11. Structure Design and Numerical Analysis of Ultra-high Pressure Perforating Gun%超高压射孔枪结构设计及数值分析

    Institute of Scientific and Technical Information of China (English)

    唐凯; 陈建波; 陈华彬; 程启文; 罗苗壮

    2012-01-01

    Introduced is a method using Pro/E to create 3D model of ultra-high pressure perforating gun and complete the finite element analysis and optimization design. In addition to considering the gun seal and bearing, the following 3 key factors should be considered in the gun design: depth and shape of blind hole related to the gun collapse pressure;internal relation between perforation parameters and perforating gun, such as the hole density, phase and so on; influence of tensile load and well temperature on the gun collapse pressure. The study result shows that the use of powerful CAD and CAE functions of Pro/E can effectively complete the gun structure design, numerical analysis and multi-parameter optimization design of the gun. After experimental verification, our designed gun considering the above factors meets the new design requirements.%介绍了利用Pro/E三维设计软件建立超高压射孔枪数值模型,进行有限元分析和优化设计的方法.考虑射孔枪的密封和承压等常规因素,在超高压射孔枪的结构设计中综合3个关键因素:影响射孔枪整体强度的盲孔深度和形状;射孔参数和射孔枪之间的内在联系,如孔密、相位等的影响;射孔枪承受拉力载荷以及井内温度等因素对射孔枪抗压强度的影响.利用Pro/E的CAD和CAE功能完成超高压射孔枪的结构设计、数值分析以及多参数联合控制优化设计.经过试验验证,综合考虑以上因素设计的超高压射孔枪满足设计要求.

  12. ION GUN

    Science.gov (United States)

    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)

  13. Gun Safety

    Science.gov (United States)

    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 ...

  14. Gun Control

    OpenAIRE

    Moore, Mark; Cook, Phil; Braga, Anthony

    2001-01-01

    The purpose of this essay is to provide a foundation for understanding the "Great American Gun War," and to consider the next steps that could be taken in the search for an effective gun-control policy. We begin with a review of the more-or-less uncontroversial facts about trends in gun ownership and use, and the reasons why Americans are inclined to arm themselves. A discussion follows of the more contentious issues, whether and how guns influence levels or seriousness of crime. We then iden...

  15. Low-pressure plasma treatment of polylactide fibers for enhanced mechanical performance of fiber-reinforced calcium phosphate cements

    OpenAIRE

    Canal Barnils, Cristina; Gallinetti, Sara; Ginebra Molins, Maria Pau

    2014-01-01

    Calcium phosphate cements (CPCs) are extensively used as synthetic bone grafts, but their poor mechanical properties limit their applicability to non-stress-bearing applications. The aim of the present work is to evaluate the potential of plasma surface modification of polylactide (PLA) fibers for reinforcement of CPCs. Oxygen low-pressure plasma was employed at different treatment times and the surface properties of the untreated and plasma-treated PLA were evaluated. Plasma treatment on the...

  16. Radioactivity leach tests under high hydrostatic pressure on full size monolithic cement packages of LWR wastes for sea dumping

    International Nuclear Information System (INIS)

    Monolithic cement-solidified products of simulated evaporator concentrates from LWR packaged in 200 l drums have been subjected to leach tests of radionuclides. The leach tests were crrried out under the condition which simulates hydrostatic pressure, temperature and flow velocity on the sea bed of 5,000 m depth. The principal results are obtained as follows: (1) No radioactivity in the leachant could be detected during the test extended to 675 hr on a cement-solidified product with asphalt capping. Water ingress through the asphalt capping layer was not perceived. (2) Solidified packages with intentionally prepared bare surface were tested to find out leaching coefficients(apparent diffusion coefficients) F sub(l). Values of F sub(l) were found to be 1.6 x 10-4 for 137Cs and 1.2 x 10-9 cm2/day for 60Co, in case of the blast furnace slag cement (C-class) solidified product of simulated waste from BWR. As to the Portland cement-solidified product of simulated PWR waste, F sub(l) was 1.5 x 10-3 cm2/day for 137Cs. (3) By using these leaching coefficients, a long-term estimation of the amounts leached out was attempted considering the decay of radionuclides. (author)

  17. Large Bore Powder Gun Qualification (U)

    Energy Technology Data Exchange (ETDEWEB)

    Rabern, Donald A. [Los Alamos National Laboratory; Valdiviez, Robert [Los Alamos National Laboratory

    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.

  18. Gun Control, Gun Ownership, and Suicide Prevention.

    Science.gov (United States)

    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)

  19. A gasdynamic gun driven by gaseous detonation.

    Science.gov (United States)

    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

  20. A gasdynamic gun driven by gaseous detonation

    Science.gov (United States)

    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.

  1. Chemical structure of cement aged at normal and elevated temperatures and pressures

    International Nuclear Information System (INIS)

    The prime objective of the plug-and-abandon operations is to provide zonal isolation for infinite time. Cement-based materials are generally used as plugging materials. Therefore, it is important to understand the physical and chemical processes causing cement degradation in the downhole environment. In this study, we have characterised a Class G oilwell cement immersed for 1 year in brine at T=293 K, p=105 Pa and T=353 K, p=7x106 Pa using NMR and XRD techniques. In order to have a better understanding of the 27Al NMR spectra, selective dissolution has been performed. The results show that after 1 year of immersion in brine at T=293 K, p=105 Pa, monosulfate is converted to Friedel's salt. Leaching resulted in the disappearance of portlandite and the formation of calcite and a more polymerised calcium silicate hydrates (C-S-H). In the T=353 K, p=7x106 Pa mineralogy, ettringite is converted to hydrogrossular

  2. Spectrometer gun

    Science.gov (United States)

    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.

  3. Spectrometer gun

    International Nuclear Information System (INIS)

    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. Oil-Well Cement and C3S Hydration Under High Pressure as Seen by In Situ X-Ray Diffraction, Temperatures ;= 80 degrees C with No Additives

    Energy Technology Data Exchange (ETDEWEB)

    Jupe, Andrew C.; Wilkinson, Angus P.; Funkhouser, Garry P. (Halliburton); (GIT)

    2012-06-28

    The hydration kinetics of a white cement and batches of both Class G and H oil-well cements were examined between 0 and 60 MPa, at {le}80 C, using in situ synchrotron X-ray diffraction. This gives a continuous measure of the C{sub 3}S (Ca{sub 3}SiO{sub 5}), CH (Ca(OH){sub 2}), C{sub 4}AF (Ca{sub 2}FeAlO{sub 5}), ettringite, and other phases in the hydrating slurries. Slurries prepared from single-phase C{sub 3}S; synthetic C{sub 4}AF, and gypsum; and white cement, synthetic C{sub 4}AF and gypsum were also examined. An increasing pressure enhanced the rate of hydration for all slurries. Analysis of the data, using a kinetic model, provided rate constants that were used to obtain activation volumes for C{sub 3}S hydration. For all the cement and C{sub 3}S slurries studied, similar activation volumes were obtained (average {Delta}V{double_dagger}{sup -}-35 cm{sup 3}/mol), indicating that the presence of cement phases other than C{sub 3}S has a modest influence on the pressure dependence of C{sub 3}S hydration. An alternative analysis, using the time at which 90% of the initial C{sub 3}S remained, gave similar activation volumes. Pressure accelerated the formation of ettringite from synthetic C{sub 4}AF in the presence of gypsum. However, in slurries containing cement, the pressure dependence of C{sub 3}S hydration plays a major role in determining the pressure dependence of ettringite formation.

  5. Effect of pretreatment methods and chamber pressure on morphology, quality and adhesion of HFCVD diamond coating on cemented carbide inserts

    Science.gov (United States)

    Sarangi, S. K.; Chattopadhyay, A.; Chattopadhyay, A. K.

    2008-04-01

    In the present investigation, diamond coating was deposited on cemented carbide substrate by hot filament chemical vapour deposition. The effect of substrate pretreatment methods and chamber pressure on morphology, quality, and adhesion of the diamond film were studied. The carbide inserts were pretreated with acid, Murakami's solution, and Murakami's solution followed by acid, respectively. The chamber pressure was set at 6.6, 13.2, 26.4, 39.6 and 66 mbar. Deposition carried out at pressure of 26.4 and 39.6 mbar on inserts pretreated with acid exhibited uniform crystal habit and provided coating-substrate adhesion adequate for machining application. Good coating morphology was obtained when deposition was done at 6.6 mbar on carbide inserts treated with Murakami's solution. Pretreatment with Murakami's solution followed by acid and deposition at 6.6 mbar also resulted in good morphology of diamond film. Indentation (Rockwell C scale) was done on diamond-coated inserts to assess coating-substrate adhesion under three loads of 294, 588 and 980 N. The diameter of the indentation crack at the coating-substrate interface was observed under SEM. The results suggested that diamond coating deposited at medium pressure of 26.4 mbar on carbide substrate treated with acid not only exhibited best morphology but also highest coating-substrate adhesion and improved machining performance.

  6. Pyrotechnic Igniters for Liquid Propellant Gun .

    OpenAIRE

    D. K. Kharat; K. J. Daniel; K. R. Rao; A. A. Ghosh; Shah, S.T.; S. C. Mitra

    1997-01-01

    The results of a preliminary investigation on the use of liquid propellant for gun application are presented. Both regenerative and bulk loaded liquid propellant guns were used in the study.Pyrotechnic igniters were tried out for igniting the liquid propellant. Existing pyrotechnic igniters were suitably modified to obtain pressure beyond 20 MPa in less than 3 ms in the combustion chamber.

  7. Numerical Modelling of Regenerative Liquid Propellant Guns with Annular Piston

    OpenAIRE

    K. J. Daniel; D. K. Kharat; K.R. Rao; Shah, S.T.; S. C. Mitra

    1997-01-01

    The development of regenerative liquid propellant guns (RLPGs) needs due consideration of numerous interdependent parameters that affect its performance. To help in this task, computer simulation was undertaken to predict internal ballistics of a conceptual liquid propellant gun. The expected pressure and other important parameters are documented which serve as an aid to the hardware, design of the regenerative liquid propellant guns.

  8. ELECTRON GUN

    Science.gov (United States)

    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.

  9. Neutron gun

    International Nuclear Information System (INIS)

    The neutron gun combines a new core ion source of the cold type based on X-ray ionization and new cold type of neutron source working with core ion generation. The neutrons are formed from the impact of core ions on the negatively charged anode. Based on a new conversion function, the function of the positive anode becomes analogous to the beta-unstable decomposition of a neutron. A core ion and neutron amplifier in the sense of amplifying the number is derived from the beta-unstable neutron decomposition, in order to raise the output of a gun in pulsed operation by using the number amplification in the intervals between the pulses. The method of construction is simple and cheap, the equipment has purely linear acceleration or operation with circular acceleration with linear pre-acceleration as an alternative. Purely linear operation should be sufficient for medical applications, e.g. for neutron photography to replay X-ray photography and particularly for neutron scalpels in the surgical treatment of tumours. (orig./HP)

  10. Encyclopedia of Gun Control and Gun Rights.

    Science.gov (United States)

    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…

  11. Gun ownership and social gun culture.

    Science.gov (United States)

    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. PMID:26124073

  12. Isosteric Vapor Pressure – Temperature Data for Water Sorption in Hardened Cement Paste: Enthalpy, Entropy and Sorption Isotherms at Different Temperatures

    DEFF Research Database (Denmark)

    Radjy, Fariborz; Sellevold, Erik J.; Hansen, Kurt Kielsgaard

    -T data automatically during slow heating and cooling. The generated data are subjected to regression analysis leading to very close curve fitting of the P-T data and enabling appropriate enthalpy and entropy computations. The TPA system's absolute accuracy is checked by generating P-T data for pure water......PART I: In order to generate isosteric (constant mass) vapor pressure – temperature data (P-T data) for adsorbed pore water in hydrated cement paste, the Thermo Piestic Analysis system (the TPA system) described herein was developed. The TPA system generates high precision equilibrium isosteric P....... The accuracies for pressure, enthalpy and entropy are found to be 0.5% or less. PART II: The TPA-system has been used to generate water vapor pressure – temperature data for room temperature – and steam cured hardened cement pastes as well as porous vycor glass. The moisture contents range from...

  13. Analysis of system and methods for improved cementing of oil- and gas wells

    OpenAIRE

    Stensrud, Magnus

    2011-01-01

    Cement is a crucial part of well construction. If a good cement bond between the casing and well bore wall cannot be achieved in the primary cementing, expensive remedial cementing jobs or possible loss of the well bore can occur.When cementing casings and liners in deep waters or pressure depleted reservoirs there is often a small pressure margin between pore pressure and fracture pressure, this makes cement operations more complex. New cementing techniques and cements are being developed to...

  14. Sequential injection gas guns for accelerating projectiles

    Science.gov (United States)

    Lacy, Jeffrey M.; Chu, Henry S.; Novascone, Stephen R.

    2011-11-15

    Gas guns and methods for accelerating projectiles through such gas guns are described. More particularly, gas guns having a first injection port located proximate a breech end of a barrel and a second injection port located longitudinally between the first injection port and a muzzle end of the barrel are described. Additionally, modular gas guns that include a plurality of modules are described, wherein each module may include a barrel segment having one or more longitudinally spaced injection ports. Also, methods of accelerating a projectile through a gas gun, such as injecting a first pressurized gas into a barrel through a first injection port to accelerate the projectile and propel the projectile down the barrel past a second injection port and injecting a second pressurized gas into the barrel through the second injection port after passage of the projectile and to further accelerate the projectile are described.

  15. The Gun Dispute.

    Science.gov (United States)

    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)

  16. Median Nerve Injury Due to High-Pressure Water Jet Injection: A Case Report and Review of Literature.

    Science.gov (United States)

    Emre, Ufuk; Unal, Aysun

    2009-08-01

    High-pressure injuries that occur accidentally are potentially destructive injuries that often affect the nondominant hands of young men. A variety of products such as paint, gasoline, grease, fuel oil, cement, thinner and solvents have been reported as destructive agents. High-pressure water jet injection injuries to soft tissues have rarely been reported. In this study, we present the first case of median nerve injury due to high-pressure water jet injection by a water spray gun. PMID:26815059

  17. Hard-driven rail-gun tests

    International Nuclear Information System (INIS)

    A number of prototype rail-gun designs have been tested, powered by explosive magnetic flux compression generators. Peak currents as high as 1.3 MA were delivered. Rail guns with 50-mm-thick Kevlar fiberwound structural shells were able to survive these high currents with minimum mechanical damage and were refired after enlarging the bores 0.2 to 0.4 mm to remove arc damage. In some tests, mechanical damage occurred that was apparently caused by the rebound of the gun after firing. Although the Kevlar shells had more than adequate strength, they appeared to lack sufficient stiffness, allowing excessive deflections. The use of a steel structural shell with a Kevlar sleeve was an improvement. Intrusion into the seams of the rail guns and condensation of material from the plasma armature were observed. Improved sealing of seams is indicated. In some cases, we suspect maldistribution of current within the gun; that is, not all the current delivered to the breech of the gun seemed to reach the plasma armature. Experiments are being designed to quantify the effects discussed. Rail guns of advanced design are being fabricated. An 18-g titanium projectile was accelerated to 2.4 km/s in a 16-mm-round-bore, 0.6-m-long gun, 4-6 g polycarbonate projectiles were accelerated to 3.5 km/s in 13-mm-square-bore, 1.2-m-long rail guns. All tests were conducted at atmospheric pressure

  18. More Guns, More Crime

    OpenAIRE

    Mark Duggan

    2000-01-01

    This paper examines the relationship between gun ownership and crime. Previous research has suffered from a lack of reliable data on gun ownership. I exploit a unique data set to reliably estimate annual gun ownership rates at both the state and the county level during the past two decades. My findings demonstrate that changes in gun ownership are significantly positively related to changes in the homicide rate, with this relationship driven entirely by the impact of gun ownership on murders ...

  19. Study of cements silicate phases hydrated under high pressure and high temperature; Etude des phases silicatees du ciment hydrate sous haute pression et haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Meducin, F.

    2001-10-01

    This study concerns the durability of oil-well cementing. Indeed, in oil well cementing a cement slurry is pumped down the steel casing of the well up the annular space between it and the surrounding rock to support and protect the casing. The setting conditions of pressure and temperature may be very high (up to 1000 bar and 250 deg C at the bottom of the oil-well). In this research, the hydration of the main constituent of cement, synthetic tri-calcium silicate Ca{sub 3}SiO{sub 2}, often called C{sub 3}S (C = CaO; S = SiO{sub 2} and H H{sub 2}O), is studied. Calcium Silicate hydrates are prepared in high-pressure cells to complete their phase diagram (P,T) and obtain the stability conditions for each species. Indeed, the phases formed in these conditions are unknown and the study consists in the hydration of C{sub 3}S at different temperatures, pressures, and during different times to simulate the oil-well conditions. In a first step (until 120 deg C at ambient pressure) the C-S-H, a not well crystallized and non-stoichiometric phase, is synthesized: it brings adhesion and mechanical properties., Then, when pressure and temperature increase, crystallized phases appear such as jaffeite (Ca{sub 6}(Si{sub 2}O{sub 7})(OH){sub 6}) and hillebrandite (Ca{sub 2}(SiO{sub 3})(OH){sub 2}). Silicon {sup 29}Si Nuclear Magnetic Resonance (using standard sequences MAS, CPMAS) allow us to identify all the silicates hydrates formed. Indeed, {sup 29}Si NMR is a valuable tool to determine the structure of crystallized or not-well crystallized phases of cement. The characterization of the hydrated samples is completed by other techniques: X- Ray Diffraction and Scanning Electron Microscopy. The following results are found: jaffeite is the most stable phase at C/S=3. To simulate the hydration of real cement, hydration of C{sub 3}S with ground quartz and with or without super-plasticizers is done. In those cases, new phases appear: kilchoanite mainly, and xonotlite. A large amount of

  20. Cement Conundrum

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China aims to streamline the crowded cement industry Policymakers are looking to build a concrete wall around the cement-making industry as they seek to solidify the fluid cement market and cut excessive production.

  1. Plasma focusing in coaxial gun

    International Nuclear Information System (INIS)

    A capacitor bank has been discharged between two coaxial electrodes of 6.6 cm outer diameter, 3.2 cm inner diameter and length of 31.5 cm. filled with hydrogen gas at pressure of 310 μHg. Results show that, the axial and radial plasma current reach a maximum value at a position adjacent to the gun muzzle, at which the plasma focus occurs. The measurement of the electron temperature and density and azimuthal electric field along the axis of the expansion chamber, gives a maximum value at z∼18 cm from the gun muzzle, while the axial plasma current and velocity has a minimum value at that position. These results indicate that a second point of a plasma focus has been formed at z∼18 cm from the gun muzzle, along the axis of the expansion chamber

  2. Using a controlled pressure field emission gun scanning electron microscope to acquire EBSD data on non-conductive samples

    International Nuclear Information System (INIS)

    The present work is dealing with electron backscattered diffraction. It is well known that EBSD requires most of the time and up to now, both an important high voltage and a large beam current. However, in such conditions, acquiring EBSD maps on non-conductive samples require to either coat the sample with a conductive thin layer or to use a controlled pressure SEM and then introduce some gas in the sample chamber. The idea here is to present some data comparisons between both solutions. Patterns, orientation images and simulations were carried out to try to access meaningful quantitative results.

  3. Modeling internal ballistics of gas combustion guns.

    Science.gov (United States)

    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

  4. Pore structure of blended cement paste by means of pressurization¿depressurization cycling mercury intrusion porosimetry

    NARCIS (Netherlands)

    Zhang, Y.; Wu, B.; Zhou, J.; Ye, G.; Shui, Z.

    2014-01-01

    Concrete containing supplementary cementitious materials (SCMs) has different durability properties from that containing pure Portland cement. The durability of concrete is always associated with the properties of microstructure, especially pore structure. Pressurization–Depressurization Cycling Mer

  5. Pore structure of blended cement paste by means of pressurization¿depressurization cycling mercury intrusion porosimetry

    OpenAIRE

    Zhang, Y.; Wu, B.; Zhou, J.; Ye, G.; Shui, Z.

    2014-01-01

    Concrete containing supplementary cementitious materials (SCMs) has different durability properties from that containing pure Portland cement. The durability of concrete is always associated with the properties of microstructure, especially pore structure. Pressurization–Depressurization Cycling Mercury Intrusion Porosimetry (PDC-MIP) was recently developed which can overcome the “ink bottle” effect and provide a more accurate estimation of the pore size distribution in cement-based materials...

  6. Guns and Violence. Current Controversies.

    Science.gov (United States)

    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…

  7. Gun Safety (For Kids)

    Science.gov (United States)

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

  8. Electron gun for SSRF

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A 100 kV triode-electron-gun has been designed and manufactured for the Linac of Shanghai Synchrotron Radiation Facility (SSRF). In this paper the performance of the gun and some key components are described.

  9. The internal ballistics of a leaking gun

    Directory of Open Access Journals (Sweden)

    D. S. Kothari

    1952-09-01

    Full Text Available The dynamical problem of the motion of the shot in the gun, which is rendered complicated as it has to take account of  the irreversible processes in the gun such as the physical shot-start pressure, the bore resistance and the heat-loss to the barrel, and the flow of the gas behind the shot. In the theory of an orthodox gun, the effect of the gas-flow is taken, account of by the so-called ‘Lagrange corrections.  

  10. Pyrotechnic Igniters for Liquid Propellant Gun .

    Directory of Open Access Journals (Sweden)

    D. K. Kharat

    1997-04-01

    Full Text Available The results of a preliminary investigation on the use of liquid propellant for gun application are presented. Both regenerative and bulk loaded liquid propellant guns were used in the study.Pyrotechnic igniters were tried out for igniting the liquid propellant. Existing pyrotechnic igniters were suitably modified to obtain pressure beyond 20 MPa in less than 3 ms in the combustion chamber.

  11. Design of Double-gun High-pressure Airless Spraying Machine’s Pump Body%双枪高压无气喷涂机的泵体结构设计

    Institute of Scientific and Technical Information of China (English)

    马如宏; 俞俊海

    2015-01-01

    为了解决目前国内双枪高压无气喷涂机紧缺的现状,通过对高压无气喷涂机的分析与研究,研制出一种新型的双枪高压无气喷涂机的泵体。并基于 Fluent软件分析了该泵体管路的压力和速度的变化。泵体有一个进料口,两个出料口,输漆管采用分段拼接式,方便携带和拆卸,不受喷涂距离的限制。%In order to solve the shortage of double-gun high-pressure airless spraying machine in China ,based on the analysis and research on high-pressure airless spraying machine ,a new type of double-gun high-pressure airless spraying machine’s pump body is developed .With a feed port ,two discharging mouth ,and the segmented painting tube ,the pump body is convenient to carry and remove ,not restricted by spraying distance .The changes of pipeline pressure and spaying speed is analyzed by Fluent software .

  12. A liquid chromatography-atmospheric pressure photoionization tandem mass spectrometric method for the determination of organosulfur compounds in petroleum asphalt cements.

    Science.gov (United States)

    da Silveira, Géssica Domingos; Faccin, Henrique; Claussen, Luis; Goularte, Rayane Bueno; Do Nascimento, Paulo C; Bohrer, Denise; Cravo, Margareth; Leite, Leni F M; de Carvalho, Leandro Machado

    2016-07-29

    We present a sensitive liquid chromatography-atmospheric pressure photoionization tandem mass spectrometric (UHPLC-APPI-MS/MS) method for the determination of selected organosulfur compounds in Brazilian asphalt cements. It was possible to detect 14 organosulfur compounds of different classes where sulfoxides and sulfones presented higher sensibility in ionization than thiophenes and aromatic sulfides. A dopant-assisted APPI method was also tested, however, when chromatographic flow rate was optimized a decrease in signal was observed for all compounds. PAHs were tested and ruled out as possible interfering compounds and the matrix effect of asphalt cements was within an acceptable range for the quantification of organosulfur compounds. The proposed method was found to have satisfactory linearity and accuracy with recoveries between 83.85 and 110.28% for thianaphthene and 3-methylbenzothiophene, respectively. Therefore, the method allowed the characterization of organosulfur compounds in Brazilian asphalt cements and demonstrated changes in the amount quantified in asphaltenic and maltenic fractions after the RTFOT+SUNTEST aging process. PMID:27342135

  13. A Supersonic Ping Pong Gun

    CERN Document Server

    French, Mark; Stratton, Jim

    2013-01-01

    The Ping Pong gun or Ping Pong bazooka has been a popular and compelling tool for physics education. However, the design necessarily means the ball emerges at subsonic speed. The design has been modified to include a pressure chamber and a convergent-divergent nozzle, similar to the design of some supersonic wind tunnels. This modification results in supersonic speeds. The current design has achieved a launch speed of 406 m/sec, about Mach 1.23.

  14. Numerical Modelling of Regenerative Liquid Propellant Guns with Annular Piston

    Directory of Open Access Journals (Sweden)

    K. J. Daniel

    1997-01-01

    Full Text Available The development of regenerative liquid propellant guns (RLPGs needs due consideration of numerous interdependent parameters that affect its performance. To help in this task, computer simulation was undertaken to predict internal ballistics of a conceptual liquid propellant gun. The expected pressure and other important parameters are documented which serve as an aid to the hardware, design of the regenerative liquid propellant guns.

  15. Women and Guns. Firearm Facts.

    Science.gov (United States)

    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,…

  16. Cement Formation

    DEFF Research Database (Denmark)

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten;

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including an...... overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in cement production, is provided. Clinker formations by solid state reactions, solid−liquid and liquid...

  17. Carbon Nanotube Electron Gun

    Science.gov (United States)

    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.

  18. RF guns: a review

    International Nuclear Information System (INIS)

    Free Electron Lasers and future linear colliders require very bright electron beams. Conventional injectors made of DC guns and RF bunchers have intrinsic limitations. The recently proposed RF guns have already proven their capability to produce bright beams. The necessary effort to improve further these performances and to gain reliability is now undertaken by many laboratories. More than twenty RF gun projects both thermionic and laser-driven are reviewed. Their specific characteristics are outlined and their nominal performances are given

  19. 30 CFR 250.422 - When may I resume drilling after cementing?

    Science.gov (United States)

    2010-07-01

    ... cementing surface, intermediate, or production casing (or liners), you may resume drilling after the cement... cement has been held under pressure for 8 hours. One acceptable method of holding cement under pressure is to use float valves to hold the cement in place. (b) If you plan to nipple down your diverter...

  20. Oil-Well Cement and C[subscript 3]S Hydration Under High Pressure as Seen by In Situ X-Ray Diffraction, Temperatures 80[degrees]C with No Additives

    Energy Technology Data Exchange (ETDEWEB)

    Jupe, Andrew C.; Wilkinson, Angus P.; Funkhouser, Gary P. (Halliburton); (GIT)

    2013-01-10

    The hydration kinetics of a white cement and batches of both Class G and H oil-well cements were examined between 0 and 60 MPa, at {le}80 C, using in situ synchrotron X-ray diffraction. This gives a continuous measure of the C{sub 3}S (Ca{sub 3}SiO{sub 5}), CH (Ca(OH){sub 2}), C{sub 4}AF (Ca{sub 2}FeAlO{sub 5}), ettringite, and other phases in the hydrating slurries. Slurries prepared from single-phase C{sub 3}S; synthetic C{sub 4}AF, and gypsum; and white cement, synthetic C{sub 4}AF and gypsum were also examined. An increasing pressure enhanced the rate of hydration for all slurries. Analysis of the data, using a kinetic model, provided rate constants that were used to obtain activation volumes for C{sub 3}S hydration. For all the cement and C{sub 3}S slurries studied, similar activation volumes were obtained (average {Delta}{double_dagger}{approx}-35 cm{sup 3}/mol), indicating that the presence of cement phases other than C{sub 3}S has a modest influence on the pressure dependence of C{sub 3}S hydration. An alternative analysis, using the time at which 90% of the initial C{sub 3}S remained, gave similar activation volumes. Pressure accelerated the formation of ettringite from synthetic C{sub 4}AF in the presence of gypsum. However, in slurries containing cement, the pressure dependence of C{sub 3}S hydration plays a major role in determining the pressure dependence of ettringite formation.

  1. Physico-chemical investigation of cement carbonation in aqueous solution in equilibrium with calcite and with a controlled CO2 partial pressure at 25 and 50 deg. C

    International Nuclear Information System (INIS)

    In the framework of radioactive waste geological disposal, structural concretes have to be adapted to underground chemical conditions. For concrete in water saturated medium, it is believed that carbonation will have a major impact on the interaction between concrete and the geological medium. So, to understand the complex degradation of the cement paste in that context, it is interesting to study a simplified system such as degradation in carbonated water solution. This solution must be at equilibrium with a CO2 partial pressure 30 times higher than the atmospheric pCO2, to reproduce underground natural conditions of Callovo-Oxfordian clayey rock of Bure (France). In this study, the behaviour of a new low pH material (CEM I + silica fume + fly ashes) is compared with a CEM I cement paste, both of them being submitted to carbonation in aqueous solution in equilibrium with calcite and with a pCO2 equal to 1.32 kPa (1.3 10-2 atm). Two different temperatures, 25 and 50 C, are considered. To realize these experiments, two different original types of devices were developed

  2. CEMENT SLURRIES FOR GEOTHERMAL WELLS CEMENTING

    OpenAIRE

    Nediljka Gaurina-Međimurec; Davorin Matanović; Gracijan Krklec

    1994-01-01

    During a well cementing special place belongs to the cement slurry design. To ensure the best quality of cementing, a thorough understanding of well parameters is essential, as well as behaviour of cement slurry (especially at high temperatures) and application of proven cementing techniques. Many cement jobs fail because of bad job planning. Well cementing without regarding what should be accomplished, can lead to well problems (channels in the cement, unwanted water, gas or fluid production...

  3. The Missing Gun The Missing Gun

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ma Shan, a criminal poljceman in a remotesmall town in the southwestern Yunnan province,gets drunk at his sister’s wedding and has his three-bullet gun lost, He tries to find it stealthily but endsup in vain. He has tno choice but to report the

  4. Lake Wobegon's Guns: Overestimating Our Gun-Related Competences

    OpenAIRE

    Emily Stark; Daniel Sachau

    2016-01-01

    The Lake Wobegon Effect is a general tendency for people to overestimate their own abilities. In this study, the authors conducted a large, nationally-representative survey of U.S. citizens to test whether Americans overestimate their own gun-relevant personality traits, gun safety knowledge, and ability to use a gun in an emergency. The authors also tested how gun control attitudes, political identification, gender, and gun experience affect self-perceptions. Consistent with prior research o...

  5. Rarefaction wave gun propulsion

    Science.gov (United States)

    Kathe, Eric Lee

    A new species of gun propulsion that dramatically reduces recoil momentum imparted to the gun is presented. First conceived by the author on 18 March 1999, the propulsion concept is explained, a methodology for the design of a reasonable apparatus for experimental validation using NATO standard 35mm TP anti-aircraft ammunition is developed, and the experimental results are presented. The firing results are juxtaposed by a simple interior ballistic model to place the experimental findings into a context within which they may better be understood. Rarefaction wave gun (RAVEN) propulsion is an original contribution to the field of armament engineering. No precedent is known, and no experimental results of such a gun have been published until now. Recoil reduction in excess of 50% was experimentally achieved without measured loss in projectile velocity. RAVEN achieves recoil reduction by means of a delayed venting of the breech of the gun chamber that directs the high enthalpy propellant gases through an expansion nozzle to generate forward thrust that abates the rearward momentum applied to the gun prior to venting. The novel feature of RAVEN, relative to prior recoilless rifles, is that sufficiently delayed venting results in a rarefaction wave that follows the projectile though the bore without catching it. Thus, the projectile exits the muzzle without any compromise to its propulsion performance relative to guns that maintain a sealed chamber.

  6. Rethinking Gun Violence

    OpenAIRE

    Greenberg, Mark; Litman, Harry

    2010-01-01

    This working paper develops the argument of "Gun Violence and Gun Control" (also posted on SSRN), a short piece commissioned by the London Review of Books. We decided not to publish either paper, in part because we felt there were empirical issues that we were not in a position to assess. We welcome comments on either paper. In this Article, we propose a new way of approaching the problem of gun violence, synthesizing features of a number of successful initiatives. We begin, in Pa...

  7. Internal ballistics of guns and rockets

    Directory of Open Access Journals (Sweden)

    Asim Ray

    1964-07-01

    Full Text Available An exact analytical solutions of the equations relating to the internals ballistics of guns and rockets in the non-isothermal model using tubular propellants which burns according to the pressure-index law has been obtained. An approximate solution to a pre-assigned level of accuracy has been presented.

  8. Collapsible pistons for light-gas guns

    Science.gov (United States)

    Teng, R. N.

    1973-01-01

    Moving and expandable parts of gun consist of pump-tube diaphragm, piston, launch-tube diaphragm, and saboted projectile. As a result of improved piston design, pressure cycle has been significantly improved by smoother buildup, increasing muzzle velocities up to 50%.

  9. CNG7 Consolidated Nail Gun

    OpenAIRE

    DeSantis, Christopher Daniel

    2015-01-01

    The purpose of my study is to create a compact, portable nail gun. The nail gun is to be used in tight spaces where hammers, pneumatic nail guns, and portable nail guns will not fit. The intended market is for homeowners renovating their houses. The short length and lightweight, compact frame make the CNG7 ideal for this market. The CNG7 is designed with minimum material waste and fewer parts than other nail guns.

  10. Dynamics modelling of biolistic gene guns

    International Nuclear Information System (INIS)

    The gene transfer process using biolistic gene guns is a highly dynamic process. To achieve good performance, the process needs to be well understood and controlled. Unfortunately, no dynamic model is available in the open literature for analysing and controlling the process. This paper proposes such a model. Relationships of the penetration depth with the helium pressure, the penetration depth with the acceleration distance, and the penetration depth with the micro-carrier radius are presented. Simulations have also been conducted. The results agree well with experimental results in the open literature. The contribution of this paper includes a dynamic model for improving and manipulating performance of the biolistic gene gun

  11. Copter Gun Explorations.

    Science.gov (United States)

    Park, John C.

    1992-01-01

    Describes an investigation in which students predict and verify the effect that the number of clicks of a toy copter gun has on the height that the copter will attain. Provides follow-up questions for the students. (MDH)

  12. High Velocity Gas Gun

    Science.gov (United States)

    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.

  13. Gun Safety (For Parents)

    Science.gov (United States)

    ... Reports? What to Say Vaccines: Which Ones & When? Smart School Lunches Emmy-Nominated Video "Cerebral Palsy: Shannon's ... If you do keep a gun in the house, it's vital to keep it out of sight ...

  14. Teen Suicide and Guns

    Science.gov (United States)

    ... Health Issues Listen Text Size Email Print Share Teen Suicide and Guns Page Content Article Body Protect ... thinking of a passing problem, not the outcome! Teen Suicide—A Big Problem Suicide is one of ...

  15. Calculating effective gun policies

    OpenAIRE

    Wodarz, Dominik; Komarova, Natalia L.

    2013-01-01

    Following recent shootings in the USA, a debate has erupted, one side favoring stricter gun control, the other promoting protection through more weapons. We provide a scientific foundation to inform this debate, based on mathematical, epidemiological models that quantify the dependence of firearm-related death rates of people on gun policies. We assume a shooter attacking a single individual or a crowd. Two strategies can minimize deaths in the model, depending on parameters: either a ban of ...

  16. Air gun test facility

    International Nuclear Information System (INIS)

    This paper describes a facility that is potentially useful in providing data for models to predict the effects of nuclear explosions on cities. IIT Research Institute has a large air gun facility capable of launching heavy items of a wide variety of geometries to velocities ranging from about 80 fps to 1100 fps. The facility and its capabilities are described, and city model problem areas capable of investigation using the air gun are presented

  17. Development of plasma cathode electron guns

    Science.gov (United States)

    Oks, Efim M.; Schanin, Peter M.

    1999-05-01

    The status of experimental research and ongoing development of plasma cathode electron guns in recent years is reviewed, including some novel upgrades and applications to various technological fields. The attractiveness of this kind of e-gun is due to its capability of creating high current, broad or focused beams, both in pulsed and steady-state modes of operation. An important characteristic of the plasma cathode electron gun is the absence of a thermionic cathode, a feature which leads to long lifetime and reliable operation even in the presence of aggressive background gas media and at fore-vacuum gas pressure ranges such as achieved by mechanical pumps. Depending on the required beam parameters, different kinds of plasma discharge systems can be used in plasma cathode electron guns, such as vacuum arcs, constricted gaseous arcs, hollow cathode glows, and two kinds of discharges in crossed E×B fields: Penning and magnetron. At the present time, plasma cathode electron guns provide beams with transverse dimension from fractional millimeter up to about one meter, beam current from microamperes to kiloamperes, beam current density up to about 100 A/cm2, pulse duration from nanoseconds to dc, and electron energy from several keV to hundreds of keV. Applications include electron beam melting and welding, surface treatment, plasma chemistry, radiation technologies, laser pumping, microwave generation, and more.

  18. 缅甸D区块Y-1井高压防气窜固井技术%High pressure and gas migration control cementing techniques for well Y-1 in block D Myanmar

    Institute of Scientific and Technical Information of China (English)

    宋健; 金衍; 陈勉; 柳贡慧

    2011-01-01

    Y-1井是缅甸D区块最深的一口探井,固井时存在高压油气层、地层漏失与垮塌严重、压力窗口窄等难题,可借鉴的邻井资料有限.为确保达到良好的固井质量,通过颗粒级配和优选添加剂等措施筛选出具有良好沉降稳定性的高密度防气窜水泥浆体系,并通过停机试验等方法全面评价了水泥浆性能,确保其能够适应井下各种工况条件.现场作业中,采取先导钻井液技术提高顶替效率,采取井口压力控制以防止漏失的发生,采用封隔式悬挂器、井口憋回压等措施增强防气窜效果.该井现场施工顺利,测井结果显示固井质量良好,达到测试等后期完井作业要求.Y-1井固井作业的成功,为该区块的油气勘探工作打下良好基础.%Well Y-1 is the deepest exploration well in block D Myanmar The cementing job is very difficult on the well, because of high pressure, fluid loss and serious collapse, narrow weight window, etc, and there is limited data for reference. To overcome these difficulties, through optimizing particles of cement and additives, the high density gas crossing proof slurry was developed. The slurry performance was tested by machine-stop method to ensure its fitness for all the cementing status. In the field tests, pilot slurry technique was taken to improve displacing efficiency. Wellhead pressure was controlled to prevent leakage. Liner hanger with packer and back pressure technique was applied to enhance the cement slurry performance on gas migration and avoiding loss in cementing job. The cementing job was finished successfully, without gas migration and loss in pumping and displacing job, and the cement quality met the requirement of well completion. The job sets an excellent example for the block in cementing job.

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

    OpenAIRE

    Mueller, Ronny; Kleinebudde, Peter

    2007-01-01

    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 dro...

  20. Electromagnetic Guns versus Conventional Guns - a performance comparison

    NARCIS (Netherlands)

    Reus, N.M. de; Weijden, J. van der

    1993-01-01

    Performance improvement is one of the key issues of Electromagnetic gun systems compared to conventional gun systems. Due to higher muzzle velocities, the gun's fire control computer will be able to predict the target's future position more accurately because prediction time will be smaller. In this

  1. Fueling by coaxial plasma guns

    International Nuclear Information System (INIS)

    The operating principles of pulsed coaxial guns are reviewed. Some problems involved with the injection of plasma beams from these guns into containment fields are described. The injection during reactor operating conditions is then discussed

  2. Ion plasma electron gun

    International Nuclear Information System (INIS)

    In the disclosed electron gun positive ions generated by a hollow cathode plasma discharge in a first chamber are accelerated through control and shield grids into a second chamber containing a high voltage cold cathode. These positive ions bombard a surface of the cathode causing the cathode to emit secondary electrons which form an electron beam having a distribution adjacent to the cathode emissive surface substantially the same as the distribution of the ion beam impinging upon the cathode. After passing through the grids and the plasma discharge chamber, the electron beam exits from the electron gun via a foil window. Control of the generated electron beam is achieved by applying a relatively low control voltage between the control grid and the electron gun housing (which resides at ground potential) to control the density of the positive ions bombarding the cathode

  3. PHERMEX electron gun development

    International Nuclear Information System (INIS)

    The PHERMEX facility is a 50-MHz standing-wave linear accelerator. Electrons are injected, accelerated, and transported to a tungsten target where bremsstrahlung x rays are generated for flash radiography of hydrodynamic systems. The purpose of this article is to describe the progress of PHERMEX electron gun development. The goal of this program is to generate and transport a 200-ns, 1-MV, 1-kA electron beam into the first PHERMEX accelerating cavity. The standard gun is operated at a pulse voltage of 550 kV, which is the limit determined by internal breakdown of the vacuum insulator. This insulator has been redesigned, and the gun has been pulsed at 750 kV without internal breakdown. At present, the current output is not limited by voltage but by a phenomenon called pulse shortening, which occurs at a pulse voltage of approximately 650 kV. The phenomenon has been investigated and the results are presented

  4. Unbalanced field RF electron gun

    Science.gov (United States)

    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.

  5. Guns and sleep

    OpenAIRE

    Quan SF

    2015-01-01

    No abstract available. Article truncated at 150 words. Gun deaths are a problem in America. Irrespective of one’s position on gun control, the statistics do not lie. According to the Centers for Disease Control and Prevention (CDC), there were 11,208 deaths caused by firearms in 2013 (1). The recent high profile cases in Cincinnati, OH, Lafayette, LA and Memphis, TN further highlight the issue. Obviously, each case of death by a firearm had its own set of underlying factors that contributed t...

  6. Guns and votes

    OpenAIRE

    Bouton, Laurent; Conconi, Paola; Pino, Francisco; Zanardi, Maurizio

    2013-01-01

    Why are U.S. congressmen reluctant to support gun control regulations, despite the fact that most Americans are in favor of them? We argue that re-election motives can help explain why politicians often take a pro-gun stance against the interests of the majority of the electorate. We describe a model in which an incumbent politician must decide on a primary issue, which is more important to a majority of voters, and a secondary issue, which a minority cares more intensely about. We derive con...

  7. Glue Guns: Aiming for Safety

    Science.gov (United States)

    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…

  8. Cement-based radioactive waste hosts formed under elevated temperatures and pressures (FUETAP concretes) for Savannah River Plant high-level defense waste

    International Nuclear Information System (INIS)

    Concretes that are formed under elevated temperatures and pressures (called FUETAP) are effective hosts for high-level radioactive defense wastes. Tailored concretes developed at the Oak Ridge National Laboratory (ORNL) have been prepared from common Portland cements, fly ash, sand, clays, and waste products. These concretes are produced by accelerated curing under mild autoclave conditions (85 to 2000C, 0.1 to 1.5 MPa) for 24 h. The solids are subsequently dewatered (to remove unbound water) at 2500C for 24 h. The resulting products are strong (compressive strength, 40 to 100 MPa), leach resistant [plutonium leaches at the rate of 10 pg/(cm2.d)], and radiolytically stable, monolithic waste forms (total gas value = 0.005 molecule/100 eV). This report summarizes the results of a 4-year FUETAP development program for Savannah River Plant (SRP) high-level defense wastes. It addresses the major questions concerning the performance of concretes as radioactive waste forms. These include leachability, radiation stability, thermal stability, thermal conductivity, impact strength, permeability, phase complexity, and effect of waste composition

  9. Gun control saves lives.

    Science.gov (United States)

    Matzopoulos, Richard

    2016-01-01

    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

  10. Gun Dealers, USA.

    Science.gov (United States)

    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…

  11. Serbian society and gun culture

    Directory of Open Access Journals (Sweden)

    Cvetković Vladimir

    2006-01-01

    Full Text Available This paper questions whether one characteristic of Serbian society is a gun culture. The first part of the paper deals with some theoretical concerns and closer explanation of what is understood by the term gun culture. Few different approaches to the issue are analyzed. The concept used has three main components of the gun culture: system of positive beliefs; social symbols embodied by the gun; agent "bearers" of gun culture. The second part of the paper presents results from Small Arms and Light Weapons survey conducted in 2004 in Serbia. The results were analyzed within the theoretical framework proposed in the first part of the paper.

  12. CAPE TOWN'S TIME-GUNS

    OpenAIRE

    Bisset, W. M.

    2012-01-01

    Although a great many articles have been written on the subject of Cape Town's noon gun (the. official terminology is 'time-gun') most of the writers have not had access to the Lion Battery Fort Record Book and the existance of more than one Cape Town time-gun has only recently been recorded. By 1807 a noon gun was fired regularly from the Imhoff Battery on the seaward side of the Castle.1 On 4 August 1902 the noon gun was fired from Lion Battery on Signal Hill for the first time.2 The batter...

  13. Development of the Antares electron gun

    International Nuclear Information System (INIS)

    Antares is the Los Alamos National Laboratory 40-kJ, 1-ns, CO2 laser system that is now operational. This laser system was developed for the Intertial Confinement Fusion (ICF) program and is beginning target experiments. The distributed circuit modeling, design and operation of the large electron gun developed for the final laser power amplifier are reviewed. This gun is significant because of the large electron current area, 9 m2; the number of emitter blades, 48; the dual cathode current return; and the coaxial geometry and grid control. The gun components and their development are discussed. These include the emitter blades, the coaxial grid (to maintain constant electron current during the 5-μs pulse), the bonded stacked-ring insulator (to electrically insulate the grid/cathode), the Kapton/aluminum electron transmission windows (to provide an interface between gun vacuum and laser gas) and the vacuum shell (operated at a vacuum of 10-6 torr). A unique pressure diagnostic is also discussed

  14. CEMENT SLURRIES FOR GEOTHERMAL WELLS CEMENTING

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    1994-12-01

    Full Text Available During a well cementing special place belongs to the cement slurry design. To ensure the best quality of cementing, a thorough understanding of well parameters is essential, as well as behaviour of cement slurry (especially at high temperatures and application of proven cementing techniques. Many cement jobs fail because of bad job planning. Well cementing without regarding what should be accomplished, can lead to well problems (channels in the cement, unwanted water, gas or fluid production, pipe corrosion and expensive well repairs. Cementing temperature conditions are important because bot-tomhole circulating temperatures affect slurry thickening time, arheology, set time and compressive strength development. Knowing the actual temperature which cement encounters during placement allows the selection of proper cementing materials for a specific application. Slurry design is affected by well depth, bottom hole circulating temperature and static temperature, type or drilling fluid, slurry density, pumping time, quality of mix water, fluid loss control, flow regime, settling and free water, quality of cement, dry or liquid additives, strength development, and quality of the lab cement testing and equipment. Most Portland cements and Class J cement have shown suitable performances in geot-hermal wells. Cement system designs for geothermal wells differ from those for conventional high temperature oil and gas wells in the exclusive use of silica flour instead of silica sand, and the avoidance of fly ash as an extender. In this paper, Portland cement behaviour at high temperatures is described. Cement slurry and set cement properties are also described. Published in literature, the composition of cement slurries which were tested in geothermal conditions and which obtained required compressive strength and water permeability are listed. As a case of our practice geothermal wells Velika Ciglena-1 and Velika Ciglena-la are described.

  15. Design of a high repetition rate S-band photocathode gun

    Science.gov (United States)

    Han, Jang-Hui; Cox, Matthew; Huang, Houcheng; Pande, Shivaji

    2011-08-01

    Photocathode RF guns have been developed in many laboratories for generating high quality electron beams for free-electron lasers based on linear accelerators. Such guns can generate electron beams with an exceptionally high peak current as well as a small transverse emittance. Their applications have been recently expanded for ultrafast electron diffraction, coherent terahertz radiation, and X-ray or γ-ray radiation by Compton scattering. In this paper, we design an S-band normal-conducting gun with capabilities of high quality beam generation and high repetition rate operation. The RF design and thermal analysis of the gun cavity and coupler are introduced. Optimal position of the gun focusing solenoid for low emittance beam generation is found by performing particle tracking simulations. Then, the gun system is designed to be able to afford the optimal solenoid position. The cooling-water channel surrounding the gun cavity and coupler is designed and analyzed numerically. The pressure in the gun is simulated with a vacuum model containing the detailed inner structure of the gun. An injector for a free-electron laser application is designed by using this gun and the beam dynamics simulation is shown. A cold test with a prototype gun for confirmation of the RF design is reported.

  16. Electromagnetic Guns versus Conventional Guns - a performance comparison

    OpenAIRE

    Reus, N.M. de; Weijden, J. van der

    1993-01-01

    Performance improvement is one of the key issues of Electromagnetic gun systems compared to conventional gun systems. Due to higher muzzle velocities, the gun's fire control computer will be able to predict the target's future position more accurately because prediction time will be smaller. In this paper, an investigation is done for the expected performance increase due to the higher muzzle velocities in air defense applications using a parametric as well as a Monte-Carlo approach. The Mont...

  17. Prospects for deflagration guns

    International Nuclear Information System (INIS)

    Deflagration is a process of fluid expansion with energy addition. Its existence in plasma physics was first discovered in the back-strapped T-tube experiments. In the coaxial plasma gun configuration the operation can be simple and yet produce a clean, high density (5 x 1015 cm-3), and high kinetic energy (10 to 50 keV) collimated plasma beam. Plasma acceleration mechanism was thought to be driven by J x B force. Tapered electrodes have been used to obtain plasma beams. Scaling of the gun can be performed according to simple theory based on momentum and energy balance. Proposed plasma fueling and injection to magnetic fusion systems will be discussed

  18. Characterisation of an RF excited argon plasma cathode electron beam gun

    OpenAIRE

    Del Pozo, S.; Ribton, C; Smith, DR

    2014-01-01

    This work describes the experimental set up used for carrying out spectroscopic measurements in a plasma cathode electron beam (EB) gun. Advantages of plasma cathode guns over thermionic guns are described. The factors affecting electron beam power such as plasma pressure, excitation power and plasma chamber geometry are discussed. The maximum beam current extracted was 53 mA from a 0.5 mm diameter aperture in the plasma chamber. In this work, the electron source is an argon plasma excited at...

  19. Gun Attitudes and Fear of Crime.

    Science.gov (United States)

    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)

  20. Friction in rail guns

    Science.gov (United States)

    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.

  1. CAPE TOWN'S TIME-GUNS

    Directory of Open Access Journals (Sweden)

    W.M. Bisset

    2012-02-01

    Full Text Available Although a great many articles have been written on the subject of Cape Town's noon gun (the. official terminology is 'time-gun' most of the writers have not had access to the Lion Battery Fort Record Book and the existance of more than one Cape Town time-gun has only recently been recorded. By 1807 a noon gun was fired regularly from the Imhoff Battery on the seaward side of the Castle.1 On 4 August 1902 the noon gun was fired from Lion Battery on Signal Hill for the first time.2 The battery was built because of fears of war with Russia and had been armed with two 9- inch Rifled Muzzle Loading guns by 1891. Lion Battery was remodelled in 1911.

  2. Wisconsin SRF Electron Gun Commissioning

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

  3. The ALS Gun Electronics system

    International Nuclear Information System (INIS)

    The ALS Gun Electronics system has been designed to accommodate gun with a custom made socket and high speed electronics circuit which is capable of producing single and multiple electron bunches with time jitters measured at better than 50 PS. The system generates the gated RF signal at ground level before sending it up to the 120 KV-biased gun deck via a fiber optic cable. The current pulse width as a function of grid bias, using an Eimac 8847A planar triode simulating an electron gun, was measured to show the relationship between the two parameters

  4. Public opinion about guns in the home

    OpenAIRE

    Kellermann, A.; Fuqua-Whitley, D.; Sampson, T.; Lindenmann, W.

    2000-01-01

    Objectives—(1) Determine the frequency of gun ownership, acquisition, and transfer; (2) assess gun storage practices; and (3) compare the views of firearm owning and non-owning adults regarding the protective value of keeping a gun in the home.

  5. Weight of RCL Guns in Comparison to Conventional Guns

    Directory of Open Access Journals (Sweden)

    J. P. Sirpal

    1956-07-01

    Full Text Available A study has been made of the weight of ordnance and equipment for a given performance. The comparative weights of the RCL and the orthodox equipments have been studied and it has been found that for the same muzzle energy the weight of RCL gun is 1/4th that of orthodox gun.

  6. Investigation of Possible Wellbore Cement Failures During Hydraulic Fracturing Operations

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jihoon; Moridis, George

    2014-11-01

    We model and assess the possibility of shear failure, using the Mohr-Coulomb model ? along the vertical well by employing a rigorous coupled flow-geomechanic analysis. To this end, we vary the values of cohesion between the well casing and the surrounding cement to representing different quality levels of the cementing operation (low cohesion corresponds to low-quality cement and/or incomplete cementing). The simulation results show that there is very little fracturing when the cement is of high quality.. Conversely, incomplete cementing and/or weak cement can causes significant shear failure and the evolution of long fractures/cracks along the vertical well. Specifically, low cohesion between the well and cemented areas can cause significant shear failure along the well, but the same cohesion as the cemented zone does not cause shear failure. When the hydraulic fracturing pressure is high, low cohesion of the cement can causes fast propagation of shear failure and of the resulting fracture/crack, but a high-quality cement with no weak zones exhibits limited shear failure that is concentrated near the bottom of the vertical part of the well. Thus, high-quality cement and complete cementing along the vertical well appears to be the strongest protection against shear failure of the wellbore cement and, consequently, against contamination hazards to drinking water aquifers during hydraulic fracturing operations.

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

    Science.gov (United States)

    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.

  8. Resonant optical gun.

    Science.gov (United States)

    Maslov, A V; Bakunov, M I

    2014-05-01

    We propose a concept of a structure-a resonant optical gun-to realize an efficient propulsion of dielectric microparticles by light forces. The structure is based on a waveguide in which a reversal of the electromagnetic momentum flow of the incident mode is realized by exciting a whispering gallery resonance in the microparticle. The propelling force can reach the value up to the theoretical maximum of twice the momentum flow of the initial wave. The force density oscillates along the particle periphery and has very large amplitude. PMID:24784113

  9. The Use of an Electron Microchannel as a Self-Extracting and Focusing Plasma Cathode Electron Gun

    Science.gov (United States)

    Cornish, S.; Khachan, J.

    2016-02-01

    A new and simple type of electron gun is presented. Unlike conventional electron guns, which require a heated filament or extractor, accelerator and focusing electrodes, this gun uses the collimated electron microchannels of an inertial electrostatic confinement (IEC) discharge to achieve the same outcome. A cylindrical cathode is placed coaxially within a cylindrical anode to create the discharge. Collimated beams of electrons and fast neutrals emerge along the axis of the cylindrical cathode. This geometry isolates one of the microchannels that emerge in a negatively biased IEC grid. The internal operating pressure range of the gun is 35-190 mTorr. A small aperture separates the gun from the main vacuum chamber in order to achieve a pressure differential. The chamber was operated at pressures of 4-12 mTorr. The measured current produced by the gun was 0.1-3 mA (0.2-14 mA corrected measurement) for discharge currents of 1-45 mA and discharge voltages of 0.5-12 kV. The collimated electron beam emerges from the aperture into the vacuum chamber. The performance of the gun is unaffected by the pressure differential between the vacuum chamber and the gun. This allows the aperture to be removed and the chamber pressure to be equal to the gun pressure if required.

  10. Gun Concerns Personal for Duncan

    Science.gov (United States)

    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…

  11. Preventing gun injuries in children.

    Science.gov (United States)

    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. PMID:25646308

  12. LCLS Gun Solenoid Design Considerations

    International Nuclear Information System (INIS)

    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.

  13. Guns and sleep

    Directory of Open Access Journals (Sweden)

    Quan SF

    2015-08-01

    Full Text Available No abstract available. Article truncated at 150 words. Gun deaths are a problem in America. Irrespective of one’s position on gun control, the statistics do not lie. According to the Centers for Disease Control and Prevention (CDC, there were 11,208 deaths caused by firearms in 2013 (1. The recent high profile cases in Cincinnati, OH, Lafayette, LA and Memphis, TN further highlight the issue. Obviously, each case of death by a firearm had its own set of underlying factors that contributed to the final fatal outcome, but one wonders whether sleep deprivation can be implicated in some of them. Sleep duration in adults over the past approximately 30 years has been declining in the United States (2. A variety of reasons can be cited as underlying causes such as greater use of artificial lighting, an expanding 24 hour non-stop society, promotion of a work ethic that values “burning the midnight oil”, and use of electronic devices before bedtime ...

  14. Electric arc welding gun

    Science.gov (United States)

    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.

  15. Disintegration of Bone Cement by Continuous and Pulsating Water Jet

    OpenAIRE

    S. Hloch; Foldyna, J.; Sitek, L. (Libor); M. Zeleňák; Hlaváček, P.; Hvizdoš, P.; Kloc, J.; Monka, P.; Monková, K.; Kozak, D.; Magurová, D.

    2013-01-01

    The paper deals with the study of using continuous water jet and ultrasonic pulsating water jet for bone cement disintegration. Bone-cement Pallacos R+G (manually mixed) was disintegrated ex-vivo. Mechanical properties of the bone cement were determined by nano-indentation. Factors employed in evaluation were pressure (40, 80, 120) MPa and traverse speed for continuous water jet, pressure (8, 10, 12, 14, 16, 20) MPa and orifice type (flat, circular) for ultrasonic pulsating water jet. Depth p...

  16. The Effects of Gun Ownership Rates and Gun Control Laws on Suicide Rates

    OpenAIRE

    Mark Gius

    2011-01-01

    The purpose of the present study is to determine the effects of gun control laws and gun ownership rates on state-level suicide rates. Using the most recent data on suicide rates, gun control measures, and gun ownership rates, the results of the present study suggest that states that require handgun permits have lower gun-related suicide rates, and states that have higher gun ownership rates have higher gun-related suicide rates. Regarding non-gun suicides, results suggest that stricter gun c...

  17. Calculating effective gun control policies

    CERN Document Server

    Wodarz, Dominik

    2013-01-01

    Following recent shootings in the USA, a debate has erupted, one side favoring stricter gun control, the other promoting protection through more weapons. We provide a scientific foundation to inform this debate, based on population dynamic models that quantify the dependence of firearm-related death rates of people on gun policies. We assume a shooter attacking a single individual or a crowd. Two strategies can minimize deaths in the model, depending on parameters: either a ban of private firearms possession, or a policy allowing the general population to carry guns. In particular, the outcome depends on the fraction of offenders that illegally possess a gun, on the degree of protection provided by gun ownership, and on the fraction of the population who take up their right to own a gun and carry it with them when attacked, parameters that can be estimated from statistical data. With the measured parameters, the model suggests that if the gun law is enforced at a level similar to that in the United Kingdom, g...

  18. Guns as a Symbol of American Individualism

    Institute of Scientific and Technical Information of China (English)

    许丹

    2011-01-01

    Due to continuous gun violence, Americans' crazy love for guns has always been attacked home and abroad. Americans' passion for guns derives from individualism through the development of American history. They consider guns as a means to guarantee independence and freedom, and therefore as a symbol of American individualism.

  19. Gun barrel erosion - Comparison of conventional and LOVA gun propellants

    NARCIS (Netherlands)

    Hordijk, A.C.; Leurs, O.

    2006-01-01

    The research department Energetic Materials within TNO Defence, Security and Safety is involved in the development and (safety and insensitive munitions) testing of conventional (nitro cellulose based) and thermoplastic elastomer (TPE) based gun propellants. Recently our testing capabilities have be

  20. Child Access Prevention Laws and Nonfatal Gun

    OpenAIRE

    Jeffrey DeSimone; Sara Markowitz

    2013-01-01

    Many states have passed child access prevention (CAP) laws, which hold the gun owner responsible if a child gains access to a gun that is not securely stored. Previous research on CAP laws has focused exclusively on gun-related deaths even though most gun injuries are not fatal. We use annual hospital discharge data to investigate whether CAP laws are associated with decreased nonfatal gun injuries. Results from Poisson regressions that control for various hospital, county, and state characte...

  1. Internal Ballistics of High Velocity Special Purpose Guns

    Directory of Open Access Journals (Sweden)

    V. K. Gupta

    1976-07-01

    Full Text Available More and more conventional guns are being utilized as special purpose guns to achieve very high velocity by using unconventionally high C/W ratios. The existing methods of internal ballistics give satisfactory results only for low (less than one C/W ratios. In the present paper the basic internal ballistic equations have been modified to cater for non-linear rate of burning, cubical form function and a realistic pressure gradient between breech face and the projectile base. The equations have been numerically solved. The results for low and high C/W ratios have been compared with those obtained by using conventional methods.

  2. An RF excited plasma cathode electron beam gun design

    OpenAIRE

    Del Pozo, S.; Ribton, C; Smith, DR

    2014-01-01

    A plasma cathode electron beam (EB) gun is presented in this work. A radio frequency (RF) excited plasma at 84 MHz was used as the electron source to produce a beam power of up to 3.2 kW at -60 kV accelerating voltage. The pressure in the plasma chamber is approximately 1 mbar. The electrons are extracted from the plasma chamber to the vacuum chamber (at 10-5 mbar) through a diaphragm with a 0.5 mm diameter nozzle. Advantages over thermionic cathode guns were demonstrated empirically. Mainten...

  3. Reverse Ballistic Air Gun Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This custom-designed facility houses a suite of three air guns capable of generating accelerations up to 100,000 Gs and velocities up to 2,000 ft/s. In addition to...

  4. NASA-Ames vertical gun

    Science.gov (United States)

    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.

  5. State Gun Policy and Cross-State Externalities: Evidence from Crime Gun Tracing

    OpenAIRE

    Brian Knight

    2011-01-01

    This paper provides a theoretical and empirical analysis of cross-state externalities associated with gun regulations in the context of the gun trafficking market. Using gun tracing data, which identify the source state for crime guns recovered in destination states, we find that firearms in this market tend to flow from states with weak gun laws to states with strict gun laws, satisfying a necessary condition for the existence of cross-state externalities in the theoretical model. We also fi...

  6. Dynamic properties of composite cemented clay

    Institute of Scientific and Technical Information of China (English)

    蔡袁强; 梁旭

    2004-01-01

    In this work,the dynamic properties of composite cemented clay under a wide range of strains were studied considering the effect of different mixing ratio and the change of confining pressures through dynamic triaxial test. A simple and practical method to estimate the dynamic elastic modulus and damping ratio is proposed in this paper and a related empirical normalized formula is also presented. The results provide useful guidelines for preliminary estimation of cement requirements to improve the dynamic properties of clays.

  7. Temporal Association between Federal Gun Laws and the Diversion of Guns to Criminals in Milwaukee

    OpenAIRE

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

    2012-01-01

    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 fol...

  8. Gas loading system for LANL two-stage gas guns

    Science.gov (United States)

    Gibson, Lee; Bartram, Brian; Dattelbaum, Dana; Lang, John; Morris, John

    2015-06-01

    A novel gas loading system was designed for the specific application of remotely loading high purity gases into targets for gas-gun driven plate impact experiments. The high purity gases are loaded into well-defined target configurations to obtain Hugoniot states in the gas phase at greater than ambient pressures. The small volume of the gas samples is challenging, as slight changing in the ambient temperature result in measurable pressure changes. Therefore, the ability to load a gas gun target and continually monitor the sample pressure prior to firing provides the most stable and reliable target fielding approach. We present the design and evaluation of a gas loading system built for the LANL 50 mm bore two-stage light gas gun. Targets for the gun are made of 6061 Al or OFHC Cu, and assembled to form a gas containment cell with a volume of approximately 1.38 cc. The compatibility of materials was a major consideration in the design of the system, particularly for its use with corrosive gases. Piping and valves are stainless steel with wetted seals made from Kalrez and Teflon. Preliminary testing was completed to ensure proper flow rate and that the proper safety controls were in place. The system has been used to successfully load Ar, Kr, Xe, and anhydrous ammonia with purities of up to 99.999 percent. The design of the system, and example data from the plate impact experiments will be shown. LA-UR-15-20521

  9. The case for moderate gun control.

    Science.gov (United States)

    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

  10. Silica Transport and Cementation in Quartz Aggregates

    Science.gov (United States)

    Pebble, C.; Farver, J.; Onasch, C.; Winslow, D.

    2008-12-01

    Silica transport and cementation in quartz aggregates have been experimentally investigated. Starting materials include a natural quartz arenite (Pocono sandstone), sized clasts of synthetic quartz, and sized grains of disaggregated natural sandstones. Experimental charges consisted of amorphous silica powder (~25 mg), AlCl3 powder (~3 mg), 25 wt% NaCl brine solution (~20 mg), and the starting material (~150 mg). The charges were weld-sealed in gold capsules and run in cold-seal pressure vessels at 300°C to 600°C at 150 MPa confining pressure for up to 4 weeks. Detailed calibrations of the furnaces indicate the maximum temperature variation across the length of the sample charges (3-7mm) was vacuum impregnated with epoxy containing a blue dye and sawn in half along the long axis of the sample charge. The nature and amount of silica transport and cementation in the samples was determined by a combination of Cathodoluminescence (CL), Light Microscopy (LM), and Scanning Electron Microscopy (SEM). Photomosaics of the samples were collected and the amount of cement, porosity, and average grain sizes were determined by point-counting. The cement was easily recognized from the quartz grains by the difference in luminescence. The experiments indicate that the presence of amorphous silica results in rapid silica cementation in quartz aggregates (e.g., up to 12% cement by volume in 4 weeks at 450°C). The amount of cementation is a function of substrate type, time, temperature, and ionic strength of the brine. The rate of silica transport through the length of the experimental charge appears to be limited by the silica solubility and its rapid depletion by cementation. Although most of the cement was derived from the amorphous silica, evidence for local dissolution-precipitation was observed. The experiments demonstrate that the mobility of silica, and consequent precipitation of cement, does not require a temperature or pressure gradient as is commonly assumed. Rather

  11. Lake Wobegon’s Guns: Overestimating Our Gun-Related Competences

    Directory of Open Access Journals (Sweden)

    Emily Stark

    2016-02-01

    Full Text Available The Lake Wobegon Effect is a general tendency for people to overestimate their own abilities. In this study, the authors conducted a large, nationally-representative survey of U.S. citizens to test whether Americans overestimate their own gun-relevant personality traits, gun safety knowledge, and ability to use a gun in an emergency. The authors also tested how gun control attitudes, political identification, gender, and gun experience affect self-perceptions. Consistent with prior research on the Lake Wobegon Effect, participants overestimated their gun-related competencies. Conservatives, males, and pro-gun advocates self-enhanced somewhat more than their counterparts but this effect was primarily due to increased gun experience among these participants. These findings are important to policymakers in the area of gun use, because overconfidence in one’s gun-related abilities may lead to a reduced perceived need for gun training.

  12. [Suicide with home-made gun].

    Science.gov (United States)

    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. PMID:19534397

  13. The Social Costs of Gun Ownership

    OpenAIRE

    Phillip J. Cook; Jens Ludwig

    2004-01-01

    This paper provides new estimates of the effect of household gun prevalence on homicide rates, and infers the marginal external cost of handgun ownership. The estimates utilize a superior proxy for gun prevalence, the percentage of suicides committed with a gun, which we validate. Using county- and state-level panels for 20 years, we estimate the elasticity of homicide with respect to gun prevalence as between +.1 and +.3. All of the effect of gun prevalence is on gun homicide rates. Under ce...

  14. Creativity under the Gun.

    Science.gov (United States)

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

    2002-01-01

    Although many employers think that people are most creative when under time pressure, research indicates that the opposite is true. Data from 177 employees' diaries showed that creative thinking under extreme time pressure is unlikely when people feel on a treadmill or on autopilot; more likely when they feel they are on an expedition or a…

  15. Development of an Improved Cement for Geothermal Wells

    Energy Technology Data Exchange (ETDEWEB)

    Trabits, George [Trabits Group, LLC, Wasilla, AK (United States)

    2015-04-20

    After an oil, gas, or geothermal production well has been drilled, the well must be stabilized with a casing (sections of steel pipe that are joined together) in order to prevent the walls of the well from collapsing. The gap between the casing and the walls of the well is filled with cement, which locks the casing into place. The casing and cementing of geothermal wells is complicated by the harsh conditions of high temperature, high pressure, and a chemical environment (brines with high concentrations of carbon dioxide and sulfuric acid) that degrades conventional Portland cement. During the 1990s and early 2000s, the U.S. Department of Energy’s Geothermal Technologies Office (GTO) provided support for the development of fly-ash-modified calcium aluminate phosphate (CaP) cement, which offers improved resistance to degradation compared with conventional cement. However, the use of CaP cements involves some operational constraints that can increase the cost and complexity of well cementing. In some cases, CaP cements are incompatible with chemical additives that are commonly used to adjust cement setting time. Care must also be taken to ensure that CaP cements do not become contaminated with leftover conventional cement in pumping equipment used in conventional well cementing. With assistance from GTO, Trabits Group, LLC has developed a zeolite-containing cement that performs well in harsh geothermal conditions (thermal stability at temperatures of up to 300°C and resistance to carbonation) and is easy to use (can be easily adjusted with additives and eliminates the need to “sterilize” pumping equipment as with CaP cements). This combination of properties reduces the complexity/cost of well cementing, which will help enable the widespread development of geothermal energy in the United States.

  16. Effective Permeability Change in Wellbore Cement with Carbon Dioxide Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Jung, Hun Bok; Martin, Paul F.; McGrail, B. Peter

    2011-11-01

    Portland cement, a common sealing material for wellbores for geological carbon sequestration was reacted with CO{sub 2} in supercritical, gaseous, and aqueous phases at various pressure and temperature conditions to simulate cement-CO{sub 2} reaction along the wellbore from carbon injection depth to the near-surface. Hydrated Portland cement columns (14 mm diameter x 90 mm length; water-to-cement ratio = 0.33) including additives such as steel coupons and Wallula basalt fragments were reacted with CO{sub 2} in the wet supercritical (the top half) and dissolved (the bottom half) phases under carbon sequestration condition with high pressure (10 MPa) and temperature (50 C) for 5 months, while small-sized hydrated Portland cement columns (7 mm diameter x 20 mm length; water-to-cement ratio = 0.38) were reacted with CO{sub 2} in dissolved phase at high pressure (10 MPa) and temperature (50 C) for 1 month or with wet CO{sub 2} in gaseous phase at low pressure (0.2 MPa) and temperature (20 C) for 3 months. XMT images reveal that the cement reacted with CO{sub 2} saturated groundwater had degradation depth of {approx}1 mm for 1 month and {approx}3.5 mm for 5 month, whereas the degradation was minor with cement exposure to supercritical CO{sub 2}. SEM-EDS analysis showed that the carbonated cement was comprised of three distinct zones; the innermost less degraded zone with Ca atom % > C atom %, the inner degraded zone with Ca atom % {approx} C atom % due to precipitation of calcite, the outer degraded zone with C atom % > Ca atom % due to dissolution of calcite and C-S-H, as well as adsorption of carbon to cement matrix. The outer degraded zone of carbonated cement was porous and fractured because of dissolution-dominated reaction by carbonic acid exposure, which resulted in the increase in BJH pore volume and BET surface area. In contrast, cement-wet CO{sub 2}(g) reaction at low P (0.2 MPa)-T (20 C) conditions for 1 to 3 months was dominated by precipitation of micron

  17. A CONSTITUTIVE LAW OF CEMENT-BASED MATERIAL AT LARGE RANGE OF CONFINING PRESSURE STATE%水泥基材料在宽围压范围的本构模型

    Institute of Scientific and Technical Information of China (English)

    张研; 邵建富

    2011-01-01

    The triaxial compression test and hydrostatic compression test have been performed at first.Based on the experimental data, different mechanism of cement paste has been analyzed. According to thermodynamics theory, a new constitutive law is established and the damage criterion, two plastic mechanisms have been taken into account. This modelling considers also the influence of confining pressure. Numerical simulation shows that this constitutive law for cement-based materials can well explicit the main mechanical behavior at a large range of confining pressure state.%论文首先进行了水泥石的三轴试验和静水试验,根据试验结果分析了宽围压范围下不同力学机理对水泥石宏观力学性能的影响.提出了基于热力学定律的剪切塑性、孔隙塑性与破坏准则相互作用的弹塑性损伤本构模型.该模型有效的考虑了围压对材料主要力学特征的影响,提出了与损伤准则相关联的塑性硬化函数.数值解答与试验结果比较表明,该本构模型可以很好地描述水泥石在低围压状态下的脆性、中围压下的脆-塑性转换以及高围压下的孔隙塑性为主的力学特征.

  18. Gas-gun facility for shock wave research at BARC

    International Nuclear Information System (INIS)

    For carrying out shock-wave experiments on materials, we have built a 63 mm diameter gas-gun facility at our laboratory. It is capable of accelerating projectiles (about half kg in weight) to velocities up to 1 km/s using N2 and He gases. These on impacting a target generate shock pressures up to 40 GPa, depending upon the impedance of the impactor and the target. The barrel of the gun is slotted so that a keyed projectile can be fired for combined compression- shear studies. Large samples can be shocked (about 60 mm diameter and 5-10 mm thick), with pressures lasting for a few microseconds. The gun is similar in design to the one at Washington State University. A number of diagnostic techniques have also been developed. These include measurement of projectile velocity, tilt between the impactor and the target, shock velocity in the target, and time resolved in-material stress wave histories in the shock loaded samples. Recovery capsules have also been made to retrieve shocked samples on unloading, which are then analysed using microscopic techniques like x-ray diffraction, Raman and electron microscopy. The gun has been performing well and has already been used for a few phase transition studies. (author). 73 refs., 42 figs

  19. Electrical properties of a co-axial plasma gun

    International Nuclear Information System (INIS)

    The main interest of this work is to study the power discharge of capacitor bank through a coaxial electrodes system. Such arrangement is called the coaxial gun or coaxial accelerator. It is used in jet propulsion and in triggering of discharge in turbo engines or in plasma combustion arrangement. The main goal is to find out the efficiency of the system in both cases. coaxial plasma gun system has been constructed for this course of study. The plasma gun system consists of the plasma gun tube and the discharge chamber, the capacitor bank, the triggering system the vacuum system, the power supply, and safety and dumping system. Simple and efficient diagnostic techniques were used to measure the different parameters concerning the coaxial discharge system such as the Rogowski loop, the voltage divider, the magnetic probes, the double electric probe. Results were obtained using argon gas with an operating pressure ranging from 0.1 torr to 1 torr. The peak discharge current in the first half cycle was 44 K A with rise time of 6.25 μs for a bank charging voltage of 10 kv and gas pressure of 0.9 torr. 4-26 figs., 4-8 tabs., 33 refs

  20. Repetitive, small-bore two-stage light gas gun

    International Nuclear Information System (INIS)

    A repetitive two-stage light gas gun for high-speed pellet injection has been developed at Oak Ridge National Laboratory. In general, applications of the two-stage light gas gun have been limited to only single shots, with a finite time (at least minutes) needed for recovery and preparation for the next shot. The new device overcomes problems associated with repetitive operation, including rapidly evacuating the propellant gases, reloading the gun breech with a new projectile, returning the piston to its initial position, and refilling the first- and second-stage gas volumes to the appropriate pressure levels. In addition, some components are subjected to and must survive severe operating conditions, which include rapid cycling to high pressures and temperatures (up to thousands of bars and thousands of kelvins) and significant mechanical shocks. Small plastic projectiles (4-mm nominal size) and helium gas have been used in the prototype device, which was equipped with a 1-m-long pump tube and a 1-m-long gun barrel, to demonstrate repetitive operation (up to 1 Hz) at relatively high pellet velocities (up to 3000 m/s). The equipment is described, and experimental results are presented. 124 refs., 6 figs., 5 tabs

  1. Development of coaxial rotating-plasma gun

    International Nuclear Information System (INIS)

    A rotating-plasma gun has been devised to produce plasma streams with higher rotational velocities. The working mechanism of the gun and the results of a preliminary experiment have been described. (author)

  2. States with More Gun Owners Have More Gun-Related Suicides: Study

    Science.gov (United States)

    ... gov/news/fullstory_158931.html States With More Gun Owners Have More Gun-Related Suicides: Study But only association was found, ... HealthDay News) -- In states where there are more gun owners, there are also more gun-related suicides, ...

  3. States with More Gun Owners Have More Gun-Related Suicides: Study

    Science.gov (United States)

    ... medlineplus/news/fullstory_158931.html States With More Gun Owners Have More Gun-Related Suicides: Study But only association was found, ... HealthDay News) -- In states where there are more gun owners, there are also more gun-related suicides, ...

  4. ULTRA-LIGHTWEIGHT CEMENT

    International Nuclear Information System (INIS)

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Issues, Task 2: Review Russian Ultra-Lightweight Cement Literature, Task 3: Test Ultra-Lightweight Cements, and Task 8: Develop Field ULHS Cement Blending and Mixing Techniques. Results reported this quarter include: preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; summary of pertinent information from Russian ultra-lightweight cement literature review; laboratory tests comparing ULHS slurries to foamed slurries and sodium silicate slurries for two different applications; and initial laboratory studies with ULHS in preparation for a field job

  5. Automatic targeting of plasma spray gun

    International Nuclear Information System (INIS)

    A means for monitoring the material portion in the flame of a plasma spray gun during spraying operations is described. 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

  6. Automatic targeting of plasma spray gun

    Science.gov (United States)

    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.

  7. Results from AFWL 230 kJ coaxial plasma gun experiments

    International Nuclear Information System (INIS)

    A coaxial plasma gun has been operated on the AFWL 0.5 MJ capacitor bank. A Marshall valve actuated by an explosive detonator is used to puff hydrogen gas from a small high pressure plenum into the breech of the gun. After a set delay from the explosion the capacitor bank is discharged across the electrodes of the coaxial gun. The operating mode of the gun can be changed by varying the plenum pressure and the firing delay. Over 150 shots have been fired, varying delay, plenum pressure, and initial stored energy. Initial plenum pressures were varied from 250 to 750 psi, and firing delays ranged from 0.8 msec to 2.2 msec. Experiments were conducted at 90, 176, and 230 kJ of initial stored energy (50, 70, adn 80 kV charge). Rogowski coils were used to measure current and magnetic field within the plasma at 25 axial locations along the gun. The coils were installed in grooves on the inner surface of the outer conductor. Signals from the coils were passively integrated. Integrator time constants ranged from 95 to 114 μsec. Time histories of magnetic field profiles are presented. These are used to describe the operating mode of the gun

  8. Liquid Propellants for Advanced Gun Ammunitions

    Directory of Open Access Journals (Sweden)

    K. P. Rao

    1987-01-01

    Full Text Available With constant improvements, the conventional solid propellants for guns have almost reached their limit in performance. Liquid gun propellants are promising new comers capable of surpassing these performance limits and have numerous advantages over solid propellants. A method has been worked out to predict the internal ballistics of a liquid propellant gun and illustrated in a typical application.

  9. Liquid Propellants for Advanced Gun Ammunitions

    OpenAIRE

    K. P. Rao; A. S. Bartakke; R.G.K. Nair

    1987-01-01

    With constant improvements, the conventional solid propellants for guns have almost reached their limit in performance. Liquid gun propellants are promising new comers capable of surpassing these performance limits and have numerous advantages over solid propellants. A method has been worked out to predict the internal ballistics of a liquid propellant gun and illustrated in a typical application.

  10. Amorphous superficial generation by means of a cool cathode electronic gun

    International Nuclear Information System (INIS)

    An electron gun based on a low pressure gaseous discharge for the generation of amorphous surfaces was used. Such gun, similar to those employed for gaseous laser excitation experiments consisted of a cool cathode of 7.5 cm of diameter, which delivered a current up to 100 Angstrom to 40kV, storing energy densities up to 200J/cm2 on the samples by pulses from 10 μs to 30 μs. The system permits to control not only the tension but the gun current as well as to vary the focus changing the cathode'distance to the target. (Author)

  11. The supply and demand for guns to juveniles: Oakland’s gun tracing project

    OpenAIRE

    Calhoun, Deane; Dodge, Andrea Craig; Journel, Coraline S.; Zahnd, Elaine

    2005-01-01

    In response to Oakland, California’s high level of gun violence affecting young people, the East Oakland Partnership to Reduce Juvenile Gun Violence, a citywide collaboration, was formed in 1997. In 1999, the Partnership established the Oakland Gun Tracing Project to develop evidence-based policy recommendations aimed at reducing the supply of and demand for gun acquisition among urban youth. The advocacy project involved gathering, analyzing, and using police record and gun sale/registration...

  12. Study and development of a two-stage light gas gun

    International Nuclear Information System (INIS)

    After recalling the definition of principal dimensional internal characteristics of a light gas gun studied and developed at Commissariat a l'Energie Atomique, we present the interior ballistics calculation systems in fixed working conditions: these conditions permit to accelerate a 400 g projectile to 6500 m/s speed. About these conditions is studied the influence of some operating parameters: weight of piston, initial pressure of hydrogen, breaking pressure of diaphragms. Afterwards is presented a study of dynamic axial stresses. The consequence of these stresses in certain cross sections of gun has led to conceive the original solution of gun called gun sliding launching tube. At last, some special points appropriated to operating or working methods (optimisation of convergent, extrusion of piston, failure of diaphragms, position of target, circuits of fluids) are presented. (author)

  13. ULTRA-LIGHTWEIGHT CEMENT

    International Nuclear Information System (INIS)

    The objective of this project is to develop an improved ultra-lightweigh cement using ultralight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Problems, Task 2: Review Russian Ultra-Lightweight Cement Literature, and Task 3: Test Ultra-Lightweight Cements. Results reported this quarter include a review and summary surface pipe and intermediate casing cementing conditions historically encountered in the US and establishment of average design conditions for ULHS cements. Russian literature concerning development and use of ultra-lightweight cements employing either nitrogen or ULHS was reviewed, and a summary is presented. Quality control testing of materials used to formulate ULHS cements in the laboratory was conducted to establish baseline material performance standards. A testing protocol was developed employing standard procedures as well as procedures tailored to evaluate ULHS. This protocol is presented and discussed. finally, results of initial testing of ULHS cements is presented along with analysis to establish cement performance design criteria to be used during the remainder of the project

  14. Interactions between cement grouts and sulphate bearing ground water

    International Nuclear Information System (INIS)

    The physical, chemical and mineralogical properties of mixtures of Ordinary Portland cement and blastfurnace slag or pulverized fuel ash, exposed to a sulphate-bearing ground water at different temperatures and pressures, were investigated in order to assess the long term durability of cements for encapsulating radioactive waste and backfilling a repository. The effect of the ground water on the chemical and mineralogical characteristics of the cements is minimal. Calcite and C-S-H are present in all the samples and are durable throughout the test. Dimensional changes in the cements during setting and curing may cause weaknesses in the materials which may increase the effects of a percolating ground water. (author)

  15. CFD Modelling of Bore Erosion in Two-Stage Light Gas Guns

    Science.gov (United States)

    Bogdanoff, D. W.

    1998-01-01

    A well-validated quasi-one-dimensional computational fluid dynamics (CFD) code for the analysis of the internal ballistics of two-stage light gas guns is modified to explicitly calculate the ablation of steel from the gun bore and the incorporation of the ablated wall material into the hydrogen working cas. The modified code is used to model 45 shots made with the NASA Ames 0.5 inch light gas gun over an extremely wide variety of gun operating conditions. Good agreement is found between the experimental and theoretical piston velocities (maximum errors of +/-2% to +/-6%) and maximum powder pressures (maximum errors of +/-10% with good igniters). Overall, the agreement between the experimental and numerically calculated gun erosion values (within a factor of 2) was judged to be reasonably good, considering the complexity of the processes modelled. Experimental muzzle velocities agree very well (maximum errors of 0.5-0.7 km/sec) with theoretical muzzle velocities calculated with loading of the hydrogen gas with the ablated barrel wall material. Comparison of results for pump tube volumes of 100%, 60% and 40% of an initial benchmark value show that, at the higher muzzle velocities, operation at 40% pump tube volume produces much lower hydrogen loading and gun erosion and substantially lower maximum pressures in the gun. Large muzzle velocity gains (2.4-5.4 km/sec) are predicted upon driving the gun harder (that is, upon using, higher powder loads and/or lower hydrogen fill pressures) when hydrogen loading is neglected; much smaller muzzle velocity gains (1.1-2.2 km/sec) are predicted when hydrogen loading is taken into account. These smaller predicted velocity gains agree well with those achieved in practice. CFD snapshots of the hydrogen mass fraction, density and pressure of the in-bore medium are presented for a very erosive shot.

  16. The ELETTRA Gun Trigger module

    International Nuclear Information System (INIS)

    The ELETTRA injector is a full energy Linac. The Linac and the pulsed magnets need to be synchronized with the beam in the storage ring in order to fill it with the proper bunch pattern. Most of the triggers for the timing system are generated by a module which is named Gun Trigger module. The gun is triggered in synchronism with a reference bucket of the storage ring. It can be programmed with a delay between 2 and 864 ns, a range which covers one revolution period of the storage ring, so any arbitrary bucket of the ring can be filled. The module generates also the gun trigger for working in FEL mode, which needs a repetition from 30 to 50 ns in a 10 μs window. The jitter of all these triggers is less than 50 ps. The Gun Trigger module is developed in VMEbus standard, using TTL and ECL technology. It is remotely programmable through the ELETTRA control system. The general architecture of the ELETTRA timing system is also described in the paper

  17. Current controller for electron gun

    International Nuclear Information System (INIS)

    A beam-current controller for a triode electron gun is described that permits the voltage on the control electrode to be varied within 0-2.5 kV with 60-kV isolation of the output part of the circuit from the low-potential control-signal source. The carrier frequency for control-signal conversion is 32 khz

  18. Developments in electron gun simulation

    Energy Technology Data Exchange (ETDEWEB)

    Herrmannsfeldt, W.B.

    1994-05-01

    This paper will discuss the developments in the electron gun simulation programs that are based on EGUN and its derivatives and supporting programs. Much of the code development has been inspired by technology changes in computer hardware; the implications on EGN2 of this evolution will be discussed. Some examples and a review of the capabilities of the EGUN family will be described.

  19. Developments in electron gun simulation

    International Nuclear Information System (INIS)

    This paper will discuss the developments in the electron gun simulation programs that are based on EGUN and its derivatives and supporting programs. Much of the code development has been inspired by technology changes in computer hardware; the implications on EGN2 of this evolution will be discussed. Some examples and a review of the capabilities of the EGUN family will be described

  20. Electric rail gun application to space propulsion

    International Nuclear Information System (INIS)

    The paper examines the possibility of using the DC electric gun principles as a space vehicle propulsion system, capable of producing intermediate thrust levels. The application of an electromagnetic launch technique, called the DC electric rail gun, to the space propulsion concept of O'Neill, is examined. It is determined that the DC electric rail gun offers very high projectile accelerations and a very significant potential for reducing the size and mass of a reaction motor for space application. A detailed description of rail gun principles is given and some simple expressions for the accelerating force, gun impedance, power supply requirements, and system performance are discussed

  1. Electron gun for technological linear accelerator

    International Nuclear Information System (INIS)

    The work is purposed to the design of diode electron gun for powerful technologic electron linac and to experimental investigations of the beam parameters at the gun exit.The gun feature is the quick cathode replacement.This is very impotent for operating of the accelerator.The gun optics and beam parameters were calculated using the EGUN code.Beam parameters were investigated as at the special test stand so as component of the linac injector.The gun produces the beam current of 2 A at the anode voltage 25 kV.Measured beam parameters correspond to calculated results

  2. Revisiting Pneumatic Nail Gun Trigger Recommendations

    OpenAIRE

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

    2015-01-01

    Use of a pneumatic nail gun with a sequential actuation trigger (SAT) significantly diminishes the risk for acute traumatic injury compared to use of a contact actuation trigger (CAT) nail gun. A theoretically-based increased risk of work-related musculoskeletal disorders from use of a SAT nail gun, relative to CAT, appears unlikely and remains unproven. Based on current knowledge, the use of CAT nail guns cannot be justified as a safe alternative to SAT nail guns. This letter provides a pers...

  3. Coaxial gun parameters and X-ray emission

    International Nuclear Information System (INIS)

    The paper presents the results of investigation with 3 kJ coaxial plasma gun, which operated with argon gas at pressure 0.8 torr. The coaxial plasma gun parameters are investigated by pick up coils, double electric probe, and x-ray probe. The mean electron temperature and density of the ejected plasma are 25 eV and 1015 cm-3 respectively. The maximum kinetic pressure of the ejected plasma in the expansion chamber appears after 10 μs from the start of the discharge current. The energetic electrons is detected by an x-ray probe which showed a single pulse of electrons with energy ≅ 3 Kev. (orig.)

  4. RF Design of the LCLS Gun

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Control led electron gun with a plasma cathode

    International Nuclear Information System (INIS)

    A description of a power electron gun with a plasma cathode is given. Its design is the development of gas-discharge sources of the duaplasmatron type. The basic elements of the gas-discharge source- the gun anode, the gun plasma cathode, the intermediate electrode of the source, and the tungsten thermocathode- are placed in side a high-voltage insulator. The diameter of the plasma cathode can be up to 2 cm, and the length of the accelerating gap- up to 0.3 cm. The discharge chamber is filled with Ar under 0.3 torr pressure. The electron beam focusing is carried out by means of two magnetic lenses, and displacement of the electron beam - by means of a deflecting coil. Experimental data are given on beam current control by modulating the discharge current and also by means of the electromagnetic system of the plasma gas-discharge source. The electron gun described shapes electron beams with a current up to 4.5 A under stationary operating conditions

  6. HIGH VELOCITY THERMAL GUN FOR SURFACE PREPARATION AND TREATMENT

    OpenAIRE

    I.A. Gorlach

    2012-01-01

    Many surface preparation and treatment processes utilise compressed air to propel particles against surfaces in order to clean and treat them. The effectiveness of the processes depends on the velocity of the particles, which in turn depends on the pressure of the compressed air. This paper describes a thermal gun built on the principles of High Velocity Air Fuel (HVAF) and High Velocity Oxy Fuel (HVOF) processes. The designed apparatus can be used for abrasive blasting, coating of surfaces, ...

  7. Triaxial shear behavior of a cement-treated sandegravel mixture

    Institute of Scientific and Technical Information of China (English)

    Younes Amini; Amir Hamidi

    2014-01-01

    A number of parameters, e.g. cement content, cement type, relative density, and grain size distribution, can influence the mechanical behaviors of cemented soils. In the present study, a series of conventional triaxial compression tests were conducted on a cemented poorly graded sandegravel mixture containing 30%gravel and 70%sand in both consolidated drained and undrained conditions. Portland cement used as the cementing agent was added to the soil at 0%, 1%, 2%, and 3%(dry weight) of sandegravel mixture. Samples were prepared at 70%relative density and tested at confining pressures of 50 kPa, 100 kPa, and 150 kPa. Comparison of the results with other studies on well graded gravely sands indicated more dilation or negative pore pressure in poorly graded samples. Undrained failure envelopes determined using zero Skempton’s pore pressure coefficient ðA ¼ 0Þ criterion were consistent with the drained ones. Energy absorption potential was higher in drained condition than undrained condition, suggesting that more energy was required to induce deformation in cemented soil under drained state. Energy ab-sorption increased with increase in cement content under both drained and undrained conditions.

  8. Pressure and Magnetics Measurements of Single and Merged Jets

    Science.gov (United States)

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

    2010-11-01

    We present pressure and magnetic data from both a single full scale coaxial gun and from the merging of jets from several minirailguns. The magnetic probes measure all three components of field, and include an array of probes inside the coaxial gun. Magnetic measurements beyond the muzzle of the gun show the scale of currents trapped in the plasma plume. The pressure probe measures adiabatic stagnation pressure and shows how this quantity decreases with distance from the gun as well as the changes in stagnation pressure through the merge process. Stagnation pressure is influenced by density, temperature, and velocity, and serves as a check on spectroscopic and interferometer measurements. Unlike optical measurements, stagnation pressure is taken at a definite location. These guns are early prototypes of guns to be installed on the Plasma Liner eXperiment at LANL. The jet-merging results are reviewed in the context of what is expected for PLX.

  9. System for transporting an electron beam to the atmosphere for a gun with a plasma emitter

    Science.gov (United States)

    Kornilov, S. Yu.; Rempe, N. G.; Shidlovskiy, S. V.

    2016-06-01

    We report on the results of simulation of the gas flow in a gun with a plasma emitter and in the system for extracting the electron beam to the atmosphere, constructed on the basis of standard gasdynamic windows (GDWs). The design of the gun and GDWs is described. Calculations are performed for a pressure of about 10-3 Torr in the electron beam generation range. It is shown that the pressure drop to the atmospheric pressure in the system of electron beam extraction to the atmosphere can be ensured by two GDW stages evacuated by pumps with optimal performance.

  10. In-situ Mechanical Manipulation of Wellbore Cements as a Solution to Leaky Wells

    Science.gov (United States)

    Kupresan, D.; Radonjic, M.; Heathman, J.

    2013-12-01

    Wellbore cement provides casing support, zonal isolation, and casing protection from corrosive fluids, which are essential for wellbore integrity. Cements can undergo one or more forms of failure such as debonding at cement/formation and cement/casing interface, fracturing and defects within cement matrix. Failures and defects within cement will ultimately lead to fluids migration, resulting in inter-zonal fluid migration and premature well abandonment. There are over 27,000 abandoned oil and gas wells only in The Gulf of Mexico (some of them dating from the late 1940s) with no gas leakage monitoring. Cement degradation linked with carbon sequestration can potentially lead to contamination of fresh water aquifers with CO2. Gas leaks can particularly be observed in deviated wells used for hydraulic fracking (60% leakage rate as they age) as high pressure fracturing increases the potential for migration pathways. Experimental method utilized in this study enables formation of impermeable seals at interfaces present in a wellbore by mechanically manipulating wellbore cement. Preliminary measurements obtained in bench scale experiments demonstrate that an impermeable cement/formation and cement/casing interface can be obtained. In post-modified cement, nitrogen gas flow-through experiments showed complete zonal isolation and no permeability in samples with pre-engineered microannulus. Material characterization experiments of modified cement revealed altered microstructural properties of cement as well as changes in mineralogical composition. Calcium-silicate-hydrate (CSH), the dominant mineral in hydrated cement which provides low permeability of cement, was modified as a result of cement pore water displacement, resulting in more dense structures. Calcium hydroxide (CH), which is associated with low resistance of cement to acidic fluids and therefore detrimental in most wellbore cements, was almost completely displaced and/or integrated in CSH as a result of

  11. Effects of a Gun Dealer's Change in Sales Practices on the Supply of Guns to Criminals

    OpenAIRE

    Webster, Daniel W.; 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 interrupt...

  12. The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas

    OpenAIRE

    Mark Duggan; Randi Hjalmarsson; Brian A. Jacob

    2008-01-01

    Thousands of gun shows take place in the U.S. each year. Gun control advocates argue that because sales at gun shows are much less regulated than other sales, such shows make it easier for potential criminals to obtain a gun. Similarly, one might be concerned that gun shows would exacerbate suicide rates by providing individuals considering suicide with a more lethal means of ending their lives. On the other hand, proponents argue that gun shows are innocuous since potential criminals can acq...

  13. Improving the Performance of Two-Stage Gas Guns By Adding a Diaphragm in the Pump Tube

    Science.gov (United States)

    Bogdanoff, D. W.; Miller, Robert J.

    1995-01-01

    Herein, we study the technique of improving the gun performance by installing a diaphragm in the pump tube of the gun. A CFD study is carried out for the 0.28 in. gun in the Hypervelocity Free Flight Radiation (HFF RAD) range at the NASA Ames Research Center. The normal, full-length pump tube is studied as well as two pump tubes of reduced length (approximately 75% and approximately 33% of the normal length). Significant improvements in performance are calculated to be gained for the reduced length pump tubes upon the addition of the diaphragm. These improvements are identified as reductions in maximum pressures in the pump tube and at the projectile base of approximately 20%, while maintaining the projectile muzzle velocity or as increases in muzzle velocity of approximately 0.5 km/sec while not increasing the maximum pressures in the gun. Also, it is found that both guns with reduced pump tube length (with diaphragms) could maintain the performance of gun with the full length pump tube without diaphragms, whereas the guns with reduced pump tube lengths without diaphragms could not. A five-shot experimental investigation of the pump tube diaphragm technique is carried out for the gun with a pump tube length of 75% normal. The CFD predictions of increased muzzle velocity are borne out by the experimental data. Modest, but useful muzzle velocity increases (2.5 - 6%) are obtained upon the installation of a diaphragm, compared to a benchmark shot without a diaphragm.

  14. Preparation of Polycrystalline Cubic Boron Nitride Compact by Cemented Carbide High-Pressure Infiltration%硬质合金高压熔渗制备聚晶立方氮化硼复合片

    Institute of Scientific and Technical Information of China (English)

    贾洪声; 鄂元龙; 李海波; 汪尹强; 贾晓鹏; 马红安; 郑友进

    2014-01-01

    Under high temperature and high pressure conditions (HPHT, 5.2GPa, 1450℃),homogeneous Polycrystalline Cubic Boron Nitride (PcBN)compact ofΦ15 × 5 mm has been synthesized through the cemented carbide high pressure in situ melting infil-tration method.The structure morphology and phase composition of PcBN compact has been investigated through scanning electron microscope (SEM),X-radial Diffractometer (XRD)and Energy Disperse Spectroscopy (EDS).It's mechanism of composite interface has also been discussed.The experiment result shows that the WC and Co in the cemen-ted carbide (WC-Co)substrate spread into Cubic Boron Nitride layer through melting in-filtration.And the binding phase of WC,MoCoB and Co3 W3 C facilitate the interface re-combination of the PcBN compact,hence a compact"concrete"structure has been formed on the PcBN layer.%在高温高压条件下(HPHT,5.2 GPa,1450℃),通过硬质合金基体的高压原位熔渗法,制备了质地均匀的Φ15×5 mm的聚晶立方氮化硼(PcBN)复合片。采用扫描电子显微镜(SEM)、X 射线衍射仪(XRD)、能谱仪(EDS)等考察了PcBN复合片的组织形貌及物相成分,并对其界面复合机理进行了探讨。实验结果表明,硬质合金(WC-Co)基体中 WC 及 Co 通过熔渗扩散到立方氮化硼(cBN)层,通过 WC、MoCoB、Co3 W3 C等粘结相,实现了PcBN复合片的界面复合,PcBN层形成致密的“混凝土”结构。

  15. Advanced cementation concepts

    International Nuclear Information System (INIS)

    The purpose of this programme of work was to investigate whether improvements could be made to existing formulations for cement suitable for the immobilization of intermediate level radioactive waste. Two additives were selected, microsilica and limestone flour. Improvements to the cement were only slight. (author)

  16. New Gas Gun Helping Scientists Better Understand Plutonium Behavior

    Energy Technology Data Exchange (ETDEWEB)

    Hazi, A

    2005-09-20

    One of the most daunting scientific and engineering challenges today is ensuring the safety and reliability of the nation's nuclear arsenal. To effectively meet that challenge, scientists need better data showing how plutonium, a key component of nuclear warheads, behaves under extreme pressures and temperatures. On July 8, 2003, Lawrence Livermore researchers performed the inaugural experiment of a 30-meter-long, two-stage gas gun designed to obtain those data. The results from a continuing stream of successful experiments on the gas gun are strengthening scientists' ability to ensure that the nation's nuclear stockpile is safe and reliable. The JASPER (Joint Actinide Shock Physics Experimental Research) Facility at the Department of Energy's (DOE's) Nevada Test Site (NTS) is home to the two-stage gas gun. In the gun's first test, an unqualified success, Livermore scientists fired a projectile weighing 28.6 grams and traveling about 5.21 kilometers per second when it impacted an extremely small (about 30-gram) plutonium target. This experiment marked the culmination of years of effort in facility construction, gun installation, system integration, design reviews, and federal authorizations required to bring the experimental facility online. Ongoing experiments have drawn enthusiastic praise from throughout DOE, the National Nuclear Security Administration (NNSA), and the scientific community. NNSA Administrator Linton Brooks said, ''Our national laboratories now have at their disposal a valuable asset that enhances our due diligence to certify the nuclear weapons stockpile in the absence of underground nuclear weapons testing.''

  17. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: DEVILBISS JGHV-531-46FF HVLP SPRAY GUN

    Science.gov (United States)

    This report presents the results of the verification test of the DeVilbiss JGHV-531-46FF high-volume, low-pressure pressure-feed spray gun, hereafter referred to as the DeVilbiss JGHV, which is designed for use in industrial finishing. The test coating chosen by ITW Industrial Fi...

  18. Self-bunching electron guns

    International Nuclear Information System (INIS)

    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 cold emission, long life, and tolerance to contamination. The cold emission process is based on secondary electron emission. FMT has studied this resonant bunching process which gives rise to high current densities (0.01-5 kA/cm2), high charge bunches (up to 100 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. About 5.8x1013 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 150 A/cm2. The third project involves the construction of a 34.2 GHz frequency-multiplied source driven by an X-Band MPG. Analytical work has been carried out on this device, and we are ready to proceed with design, fabrication, and testing

  19. Internal Ballistics of Recoilless Guns

    Directory of Open Access Journals (Sweden)

    Asim Ray

    1967-01-01

    Full Text Available A new method for calculating the ballistics of recoilless guns during the period of burning of the propellant has been obtained. Ballistics have also been calculated by exact numerical integration in a few cases and these results have been compared with those obtained by the method described in this paper. It has been found that the results obtained by these two methods agree satisfactorily.

  20. The Influence of the Axial Magnetic Field Upon-the Coaxial Plasma Gun Parameters

    International Nuclear Information System (INIS)

    This study concerns with the influence of an applied axial magnetic field upon the electrical parameters of a coaxial plasma gun device. The experimental results are investigated with 0.5 KJ plasma gun device operated with argon gas at a pressure of 3.5 Torr. An axial time independent magnetic field with intensity of 550 G is introduced along the plasma current sheath axial region, within the annular space between the two coaxial electrodes. From the measurements of the discharge current I(t) and the voltage V(t), the electrical discharge parameters of the plasma gun device and the plasma current sheath implosion velocity are estimated, in normal mode of plasma gun operation and in the mode of presence external axial magnetic field. A comparison between these two modes is studied

  1. Self-bunching electron guns

    CERN Document Server

    Mako, F; Weilhammer, Peter

    1999-01-01

    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 cold emission, long life, and tolerance to contamination. The cold emission process is based on secondary electron emission. FMT has studied this resonant bunching process which gives rise to high current densities (0.01-5 kA/cm/sup 2/), high charge bunches (up to 100 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 microbunches at ~20 A/cm/sup 2/ 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 mu s-long macro- pulses. About 5.8*10/sup 13/ micro-bunches or 62,000 coulombs have pass...

  2. X-Band RF Gun Development

    International Nuclear Information System (INIS)

    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.

  3. X-Band RF Gun Development

    Energy Technology Data Exchange (ETDEWEB)

    Vlieks, Arnold; Dolgashev, Valery; Tantawi, Sami; /SLAC; 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.

  4. Racism, gun ownership and gun control: biased attitudes in US whites may influence policy decisions.

    Directory of Open Access Journals (Sweden)

    Kerry O'Brien

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

  5. Racism, gun ownership and gun control:biased attitudes in US whites may influence policy decisions

    OpenAIRE

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

    2013-01-01

    OBJECTIVE: Racism is related to policies preferences and behaviors that adversely affect blacks and appear related to a fear of blacks (e.g., increased policing, death penalty). This study examined whether racism is also related to gun ownership and opposition to gun controls in US whites. METHOD: The most recent data from the American National Election Study, a large representative US sample, was used to test relationships between racism, gun ownership, and opposition to gun control in US wh...

  6. Guns, Crime, and Academics: Some Reflections on the Gun Control Debate.

    OpenAIRE

    Parker, Jeffrey S

    2001-01-01

    This comment on Thomas Marvell's "The Impact of Banning Juvenile Gun Possession" analyzes Marvell's empirical findings and their policy implications for gun control legislation. While Marvell's article stresses the absence of any finding favorable to juvenile gun bans, this comment points out that the statistical results actually support the stronger finding that some of the juvenile gun bans are associated with a statistically significant increase in homicides nationwide. Under either findin...

  7. Racism, Gun Ownership and Gun Control: Biased Attitudes in US Whites May Influence Policy Decisions

    OpenAIRE

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

    2013-01-01

    Objective Racism is related to policies preferences and behaviors that adversely affect blacks and appear related to a fear of blacks (e.g., increased policing, death penalty). This study examined whether racism is also related to gun ownership and opposition to gun controls in US whites. Method The most recent data from the American National Election Study, a large representative US sample, was used to test relationships between racism, gun ownership, and opposition to gun control in US whit...

  8. Gun Control in Australia: A Criminological Perspective

    Directory of Open Access Journals (Sweden)

    Rick Sarre

    2015-11-01

    Full Text Available In recent months there has been an upsurge in contributions to the popular press from social commentators insisting that guns make our nation safer. This essay questions these assertions. The paper provides evidence to support a contrary affirmation: that is, in order to have a reduction in gun violence, there needs to be a reduction in the number of guns generally, and a continuation of the legal controls that currently shape firearms policy in Australia.

  9. Nail-Gun Injuries to the Hand

    OpenAIRE

    Pierpont, Yvonne N.; Pappas-Politis, Effie; Naidu, Deepak K.; Salas, R. Emerick; Johnson, Erika L.; Payne, Wyatt G.

    2008-01-01

    Background: The nail gun is a commonly utilized tool in carpentry and construction. When used properly with appropriate safety precautions, it can facilitate production and boost efficiency; however, this powerful tool also has the potential to cause serious injury. The most common site of nail-gun injuries in both industrial and nonoccupational settings is the hand. Materials and Methods: We report on two patients with nail-gun injuries to the hand. A review of the literature and discussion ...

  10. Research on Hot Gunning Repairing in Laboratory

    Institute of Scientific and Technical Information of China (English)

    CAO Feng; LONG Shigang; MENG Qingmin; SUN Jialin; HONG Yanruo

    2003-01-01

    The lining of blast furnace may be damaged partly,so that gunning repair is needed. The bonding strength of boundary surface between the repairing layer and remained lining of blast furnace has been studied by thermal simulation.The factors influencing the bonding strength are the ingredient gunning repair temperature,remained lining condition and water content of gunning refractory.The bonding strength decreases with the increases of remained lining temperature.

  11. Gun Control in Australia: A Criminological Perspective

    OpenAIRE

    Rick Sarre

    2015-01-01

    In recent months there has been an upsurge in contributions to the popular press from social commentators insisting that guns make our nation safer. This essay questions these assertions. The paper provides evidence to support a contrary affirmation: that is, in order to have a reduction in gun violence, there needs to be a reduction in the number of guns generally, and a continuation of the legal controls that currently shape firearms policy in Australia.

  12. Rate control for electron gun evaporation

    International Nuclear Information System (INIS)

    Principles for obtaining high-quality rate control for electron gun evaporation are discussed. The design criteria for rate controllers are derived from this analysis. Results are presented which have been obtained with e-guns whose evaporation rate is controlled by a Wehnelt electrode or by sweeping of the electron beam. Further improvements of rate stability can be obtained by improved design of e-guns and power supplies

  13. Conceptual Design for CLIC Gun Pulser

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Tao [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-01-08

    The Compact Linear Collider (CLIC) is a proposed future electron-positron collider, designed to perform collisions at energies from 0.5 to 5 TeV, with a nominal design optimized for 3 TeV (Dannheim, 2012). The Drive Beam Accelerator consists of a thermionic DC gun, bunching section and an accelerating section. The thermionic gun needs deliver a long (~143us) pulse of current into the buncher. A pulser is needed to drive grid of the gun to generate a stable current output. This report explores the requirements of the gun pulser and potential solutions to regulate grid current.

  14. Informed Consent at Gunpoint: When Psychiatry Affects Gun Ownership.

    Science.gov (United States)

    Candilis, Philip J; Khurana, Gagandeep; Leong, Gregory B; Weinstock, Robert

    2015-06-01

    As states take more steps to connect patients' gun ownership to their mental health, psychiatrists are being asked to provide mental health information after clinical interviews as well as after confiscation. This move into the patient-physician relationship raises new questions about how psychiatrists should obtain informed consent when interviews may result in reports to legal authorities. Consent warnings are already practiced more in the breach than in the observance and informed consent is imperfect at its best. In communities torn by controversies surrounding gun control, vehement political views will further influence these established themes to result in unprecedented pressures on patient confidentiality. This analysis draws on new movements in ethical theory and behavioral medicine that go beyond balancing principles to question the use of psychiatry in firearm reporting, and support a vigorous practice of informed consent to protect both individuals and the communities they live in. PMID:25640524

  15. Magnetized Target Fusion Propulsion: Plasma Injectors for MTF Guns

    Science.gov (United States)

    Griffin, Steven T.

    2003-01-01

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

  16. Post cementation sensitivity evaluation of glass Ionomer, zinc phosphate and resin modified glass Ionomer luting cements under class II inlays: An in vivo comparative study

    Directory of Open Access Journals (Sweden)

    Chandrasekhar V

    2010-01-01

    Full Text Available Objective: This study aims to compare the patient-perceived post-cementation sensitivity of class II metal restorations preoperatively, immediately after cementation, one week after cementation and one month after cementation with (1 Glass Ionomer luting cement (2 Zinc Phosphate cement and (3 Resin-modified Glass Ionomer luting cement. Materials and Methods: A total of 60 patients, irrespective of sex, in the age group of 15-50 years were selected and the teeth were randomly divided into three groups of 20 each. Twenty inlay cast restorations were cemented with three different luting cements. The criteria adapted to measure tooth sensitivity in the present study were objective examination for sensitivity.(1 Cold water test (2 Compressed air test and (3 Biting pressure test. Results: The patients with restorations cemented with Resin-modified Glass ionomer demonstrated the least postoperative sensitivity when compared with Glass Ionomer and zinc phosphate cement at all different intervals of time evaluated by different tests. Conclusion: The patients with restorations cemented with resin-modified Glass ionomer demonstrated the least postoperative sensitivity.

  17. Tympanoplasty with ionomeric cement

    DEFF Research Database (Denmark)

    Kjeldsen, A D; Grøntved, A M

    2000-01-01

    isolated erosion of the long incus process have been treated with a new surgical technique in which the ossicular chain was rebuilt with ionomeric cement. The results in hearing performance (mean pure-tone average (PTA) 0.5, 1 and 2 kHz) were evaluated pre- and post-surgery, and compared to those in a...... > 10 dB, in 4 there was a slight improvement and in 2 a decline. The difference was not statistically significant. Hearing improvement using ionomeric cement in type II tympanoplasty was satisfactory. Reconstruction of the ossicular chain with ionomeric cement is recommended, as the procedure is easy...

  18. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2003-01-31

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. DOE joined the Materials Management Service (MMS)-sponsored joint industry project ''Long-Term Integrity of Deepwater Cement under Stress/Compaction Conditions.'' Results of the project contained in two progress reports are also presented in this report.

  19. Experimental studies of coaxial plasma gun current

    International Nuclear Information System (INIS)

    In this investigation of a coaxial plasma gun, plasma sheath currents and related behavior are examined. Plasma behavior in the gun affects gun characteristics. Plasma gun applications are determined by the plasma behavior. The AFWL PUFF capacitor bank (72 μF, 29 nH, 120 kV) drives the plasma gun using a deuterium fill gas. The gas breakdown site is isolated from the dielectric/vacuum interface in the AFWL system. Two gas values deliver gas in the system. The first delivers gas from the gun breech and the second optional valve delivers gas to the gun muzzle. Currents and voltages are measured by Rogowski coils, B probes and capacitive voltage probes. A O-D slug model is used to predict the current, inductance, gun voltage and plasma sheath velocity. The slug model assumes the sheath transits the gun with all mass in the sheath. In the snowplow mode, the plasma sheath is thin with a sharp current rise and drop. Our system operated in a transition mode between the snowplow and deflagration modes with early snowplow behavior and late deflagration behavior. Neutrons are produced in a plasma pinch at the gun muzzle, indicating snowplow behavior. The slug theory models overall gun behavior to experimental accuracy. Experimental results are compared to four theories for plasma sheath velocities: the Alfven collisionally limited model, the Rosenbluth model, the Fishbine saturated model and a single particle drift model. Experimental velocities vary from 105 to 106 m/s. Only the single particle drift and the slug model calculations are of the right magnitude (8 x 105 m/s). The Fishbine and the Rosenbluth models predict slower velocities (2 x 105 m/s). The Alfven model is not applicable to this system

  20. Lightweight cementing program increases profit from Kansas oil field

    International Nuclear Information System (INIS)

    This paper reports that single-stage, lightweight cementing in a Kansas operation improved the cement bond across a permeable oil/water sand. Additionally, pipe movement after pumping helped bond quality by preventing the slurry from beginning its transition time. This delay allowed continued transmission of hydrostatic pressure against the formation. In 1991, OXY USA Inc. completed 12 wells in the Ray field in Kansas. All wells were drilled to the Reagan sand. The sand has a distinct water/oil contact, strong water drive, and good permeability. Because of poor cement bonding across the Reagan, two-stage conventional cementing in the first eight wells did not effectively prevent excessive water production. Some of these wells had to have remedial cement squeezes and be reperforated. This work increased completion costs by about $15,000/well

  1. Asphalt cement poisoning

    Science.gov (United States)

    Asphalt; Pavement ... The substances in asphalt that can be harmful are: Hydrocarbons Industrial glues Industrial solvents Tar ... Asphalt is found in: Road paving materials Roofing materials Tile cements Asphalt may also be used for ...

  2. Crafting a Gauss Gun Demonstration

    Science.gov (United States)

    Blodgett, Matthew E.; Blodgett, E. D.

    2006-12-01

    A Gauss Gun launches a ferromagnetic projectile using a pulsed electromagnet. This demonstration provides a nice counterpoint to the popular Thompson's jumping ring demonstration, which launches a nonferromagnetic ring via repulsion of an induced current. The pulsed current must be short enough in duration so that the projectile is not retarded by lingering current in the launch solenoid, but also large enough to provide a suitably impressive velocity. This project involved an iterative design process, as we worked through balancing all the different design criteria. We recommend it as a very nice electronics design project which will produce a very portable and enjoyable demonstration. AAPT sponsor Earl Blodgett.

  3. Gun Control: The Debate and Public Policy.

    Science.gov (United States)

    Watkins, Christine

    1997-01-01

    Provides an overview and background information on the debate over gun control, as well as several teaching ideas. Handouts include a list of related topics drawn from various disciplines (economics, U.S. history), seven arguments for and against gun control, and a set of policy evaluation guidelines. (MJP)

  4. Youth Homicide and Guns. Firearm Facts.

    Science.gov (United States)

    Duker, Laurie, Ed.

    Young Americans are killed with guns at rates far higher than young people in other countries and than older Americans, with young, urban African-American males being most at risk. This fact sheet presents data on gun-related homicides among teenagers in the United States. The high rate of youth homicide in the United States is unique in the…

  5. Plasma-gun fueling for tokamak reactors

    International Nuclear Information System (INIS)

    In light of the uncertain extrapolation of gas puffing for reactor fueling and certain limitations to pellet injection, the snowplow plasma gun has been studied as a fueling device. Based on current understanding of gun and plasma behavior a design is proposed, and its performance is predicted in a tokamak reactor environment

  6. On the theory of photocathode rf guns

    Institute of Scientific and Technical Information of China (English)

    GAO Jie

    2009-01-01

    In this paper we give a set of analytical formulae to describe the characteristics of photocathode rf guns at any rf frequencies, such as energy, energy spread, bunch length, out going current, and emittance etc.as functions of the laser injection phase, which are useful in the design and practical operation of rf guns.

  7. Superconducting 112 MHz QWR electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Belomestnykh, S.; Ben-Zvi, I.; Boulware, C.H.; Chang, X.; Grimm, T.L.; Rao, T.; Siegel, B.; Skaritka, J.; Than, R.; Winowski, M.; Wu, Q.; Xin, T.; Xue, L.

    2011-07-25

    Brookhaven National Laboratory and Niowave, Inc. have designed and fabricated a superconducting 112 MHz quarter-wave resonator (QWR) electron gun. The first cold test of the QWR cryomodule has been completed at Niowave. The paper describes the cryomodule design, presents the cold test results, and outline plans to upgrade the cryomodule. Future experiments include studies of different photocathodes and use for the coherent electron cooling proof-of-principle experiment. Two cathode stalk options, one for multi-alkali photocathodes and the other one for a diamond-amplified photocathode, are discussed. A quarter-wave resonator concept of superconducting RF (SRF) electron gun was proposed at BNL for electron cooling hadron beams in RHIC. QWRs can be made sufficiently compact even at low RF frequencies (long wavelengths). The long wavelength allows to produce long electron bunches, thus minimizing space charge effects and enabling high bunch charge. Also, such guns should be suitable for experiments requiring high average current electron beams. A 112 MHz QWR gun was designed, fabricated, and cold-tested in collaboration between BNL and Niowave. This is the lowest frequency SRF gun ever tested successfully. In this paper we describe the gun design and fabrication, present the cold test results, and outline our plans. This gun will also serve as a prototype for a future SRF gun to be used for coherent electron cooling of hadrons in eRHIC.

  8. Long pulse electron gun for laser applications

    International Nuclear Information System (INIS)

    This paper reports on large-area electron guns that are critical components in many high-energy gas laser systems. The secondary emission electron (SEE) gun offers an attractive option for pulsed laser applications. With this type of cold cathode gun, a dc voltage is applied to the cathode and the electron beam is generated by secondary emission due to ion bombardment processes. The gun is controlled by modulating the source of ions which resides at ground potential. This design greatly simplifies the electron gun power system. SEE-gun systems have been developed which provide 150-220 keV beams at current densities exceeding 25 mA/cm2 with current density uniformities of approximately ±10% over areas of up to 5 x 150 cm2. Pulse lengths have ranged from 30 μs to 20 ms at repetition rates from single-pulse to 30 Hz. It is expected that the SEE-gun can be scaled to beam voltages of greater than 300 kV, beam areas greater than 1 m2, peak current densities exceeding 1 A/cm2, time-averaged current densities approx-gt 0.5 mA/cm2, pulse lengths of 0.1 μs to dc, and pulse repetition rates >1 kHz with good uniformity, high reliability and long life. Furthermore, the inherent simplicity of the SEE-gun results in low cost and a compact, light-weight system

  9. Solidification of low-level radioactive wastes in masonry cement

    International Nuclear Information System (INIS)

    Portland cements are widely used as solidification agents for low-level radioactive wastes. However, it is known that boric acid wastes, as generated at pressurized water reactors (PWR's) are difficult to solidify using ordinary portland cements. Waste containing as little as 5 wt % boric acid inhibits the curing of the cement. For this purpose, the suitability of masonry cement was investigated. Masonry cement, in the US consists of 50 wt % slaked lime (CaOH2) and 50 wt % of portland type I cement. Addition of boric acid in molar concentrations equal to or less than the molar concentration of the alkali in the cement eliminates any inhibiting effects. Accordingly, 15 wt % boric acid can be satisfactorily incorporated into masonry cement. The suitability of masonry cement for the solidification of sodium sulfate wastes produced at boiling water reactors (BWR's) was also investigated. It was observed that although sodium sulfate - masonry cement waste forms containing as much as 40 wt % Na2SO4 can be prepared, waste forms with more than 7 wt % sodium sulfate undergo catastrophic failure when exposed to an aqueous environment. It was determined by x-ray diffraction that in the presence of water, the sulfate reacts with hydrated calcium aluminate to form calcium aluminum sulfate hydrate (ettringite). This reaction involves a volume increase resulting in failure of the waste form. Formulation data were identified to maximize volumetric efficiency for the solidification of boric acid and sodium sulfate wastes. Measurement of some of the waste form properties relevant to evaluating the potential for the release of radionuclides to the environment included leachability, compression strengths and chemical interactions between the waste components and masonry cement. 15 refs., 19 figs., 9 tabs

  10. New Electron Gun System for BEPCII

    CERN Document Server

    Liu, Bo; Long Chi, Yun; Zhang, Chuang

    2005-01-01

    The new electron gun system for BEPCII has been put into operation since Nov. 2004. The article describes the design, experiment and operation of this new system. The design current of the gun is 10 A for the pulse lengths of 1 ns, 2.5 ns and 1 μs with repetition rate of 50 Hz. The gun is operated with a pulsed high voltage power supply which can provide up to 200 kV high voltage. Computer simulations have been carried out in the design stage, including simulation of the gun geometry and beam transportation. Some important relation curves are obtained during the experiment. Two-bunch operation is available and some elementary tests have been performed. New scheme of the gun control system based on EPICS is also presented. The real operation shows that the design and manufacturing is basically successful.

  11. Beam dynamics studies for photocathode RF gun

    International Nuclear Information System (INIS)

    Photocathode RF guns are very popular choice as injector for low emittance beams especially to light sources world wide. In demand for these gun is increasing steadily and efforts are on to make 2.6 cell RF Gun as SAMEER as proto type for future use at various laboratories. The base design of this 2.6 cell RF Gun is ready and fabrication is planned in near future. In this paper, we present beam dynamic study results of the gun and methodology to arrive at the operating point. Simulation results for Gaussian with nano-second pulse length will be discussed in detail and proposal for generation of few MeV beam will be presented. (author)

  12. Seepage/Cement Interactions

    International Nuclear Information System (INIS)

    The Development Plan (CRWMS M andO 1999a) pertaining to this task defines the work scopes and objectives for development of various submodels for the Physical and Chemical Environment Abstraction Model for TSPA-LA. The Development Plan (CRWMS M andO 1999a) for this specific task establishes that an evaluation be performed of the chemical reactions between seepage that has entered the drift and concrete which might be used in the repository emplacement drifts. The Development Plan (CRWMS M andO 1999a) then states that the potential effects of these water/grout reactions on chemical conditions in the drift be assessed factoring in the influence of carbonation and the relatively small amount of grout. This task is also directed at: (1) developing a conceptualization of important cement/seepage interactions and potential impacts on EBS performance, (2) performing a screening analysis to assess the importance of cement/seepage interactions. As the work progresses and evolves on other studies, specifically the Engineered Barrier System: Physical and Chemical Environment (P andCE) Model (in progress), many of the issues associated with items 1 and 2, above, will be assessed. Such issues include: (1) Describing the mineralogy of the specified cementitious grout and its evolution over time. (2) Describing the composition of the water before contacting the grout. (3) Developing reasonable upper-bound estimates for the composition of water contacting grout, emphasizing pH and concentrations for anions such as sulfate. (4) Evaluating the equilibration of cement-influenced water with backfill and gas-phase CO2. (5) Developing reasonable-bound estimates for flow rate of affected water into the drift. The concept of estimating an ''upper-bound'' range for reaction between the grout and the seepage, particularly in terms of pH is based on equilibrium being established between the seepage and the grout. For example, this analysis can be based on equilibrium being established as

  13. Two-stage plasma gun based on a gas discharge with a self-heating hollow emitter

    International Nuclear Information System (INIS)

    The paper presents the results of tests of a new compact two-stage bulk gas plasma gun. The plasma gun is based on a nonself-sustained gas discharge with an electron emitter based on a discharge with a self-heating hollow cathode. The operating characteristics of the plasma gun are investigated. The discharge system makes it possible to produce uniform and stable gas plasma in the dc mode with a plasma density up to 3x109 cm-3 at an operating gas pressure in the vacuum chamber of less than 2x10-2 Pa. The device features high power efficiency, design simplicity, and compactness.

  14. Design of Fit-for-Purpose Cement to Restore Cement-Caprock Seal Integrity

    Science.gov (United States)

    Provost, R.

    2015-12-01

    This project aims to study critical research needs in the area of rock-cement interfaces, with a special focus on crosscutting applications in the Wellbore Integrity Pillar of the SubTER initiative. This study will focus on design and test fit-for-purpose cement formulations. The goals of this project are as follows: 1) perform preliminary study of dispersing nanomaterial admixtures in Ordinary Portland Cement (OPC) mixes, 2) characterize the cement-rock interface, and 3) identify potential high-performance cement additives that can improve sorption behavior, chemical durability, bond strength, and interfacial fracture toughness, as appropriate to specific subsurface operational needs. The work presented here focuses on a study of cement-shale interfaces to better understand failure mechanisms, with particular attention to measuring bond strength at the cement-shale interface. Both experimental testing and computational modeling were conducted to determine the mechanical behavior at the interface representing the interaction of cement and shale of a typical wellbore environment. Cohesive zone elements are used in the finite element method to computationally simulate the interface of the cement and rock materials with varying properties. Understanding the bond strength and mechanical performance of the cement-formation interface is critical to wellbore applications such as sequestration, oil and gas production and exploration and nuclear waste disposal. Improved shear bond strength is an indication of the capability of the interface to ensure zonal isolation and prevent zonal communication, two crucial goals in preserving wellbore integrity. Understanding shear bond strength development and interface mechanics will provide an idea as to how the cement-formation interface can be altered under environmental changes (temperature, pressure, chemical degradation, etc.) so that the previously described objectives can be achieved. Sandia National Laboratories is a multi

  15. The Ames Vertical Gun Range

    Science.gov (United States)

    Karcz, J. S.; Bowling, D.; Cornelison, C.; Parrish, A.; Perez, A.; Raiche, G.; Wiens, J.-P.

    2016-01-01

    The Ames Vertical Gun Range (AVGR) is a national facility for conducting laboratory- scale investigations of high-speed impact processes. It provides a set of light-gas, powder, and compressed gas guns capable of accelerating projectiles to speeds up to 7 km s(exp -1). The AVGR has a unique capability to vary the angle between the projectile-launch and gravity vectors between 0 and 90 deg. The target resides in a large chamber (diameter approximately 2.5 m) that can be held at vacuum or filled with an experiment-specific atmosphere. The chamber provides a number of viewing ports and feed-throughs for data, power, and fluids. Impacts are observed via high-speed digital cameras along with investigation-specific instrumentation, such as spectrometers. Use of the range is available via grant proposals through any Planetary Science Research Program element of the NASA Research Opportunities in Space and Earth Sciences (ROSES) calls. Exploratory experiments (one to two days) are additionally possible in order to develop a new proposal.

  16. Gun Violence, Mental Illness, And Laws That Prohibit Gun Possession: Evidence From Two Florida Counties.

    Science.gov (United States)

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

    2016-06-01

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

  17. Environmental impacts of air-gun surveys on glass sponges : final report

    Energy Technology Data Exchange (ETDEWEB)

    Tunnicliffe, V.; Yahel, G. [Victoria Univ., Victoria, BC (Canada). Dept. of Biology; Chapman, R.; Wilmut, M. [Victoria Univ., Victoria, BC (Canada). School of Earth and Ocean Sciences

    2008-09-15

    Air-gun surveys associated with the oil and gas exploration in the Queen Charlotte Basin will insonify the seafloor with broadband, high intensity noise, exposing the glass sponge reef systems of that area to acoustic impacts. Tissue integrity and behaviour of marine animals can be affected by the acoustic harassment of water propagated vibration. This paper examined the effects of acoustic noise on the behaviour of glass sponges. The purpose of the study was to test the hypothesis that the acoustic vibration produced by a small, surface operated air gun would not alter the normal pattern of sponge feeding activities. The paper described the methods, with particular reference to the study site; sponge pumping rate; and acoustic effects on sponge pumping. Results were presented for ambient conditions; air gun shots; sponge pumping responses to air gun shots; and correlation of sponge response and ambient current. The question of whether the sponge's excurrent flow responds to the pressure from a series of air-gun shots was addressed by a statistical analysis over all the excurrent data from the experiment. It was concluded that there is little or no evidence that the acoustic pressure from the shots influences the physiological functions of the sponge. 22 refs., 2 tabs., 11 figs.

  18. Simple light gas guns for hypervelocity studies

    International Nuclear Information System (INIS)

    Two-stage light guns are used extensively in hypervelocity research. The applications of this technology include impact studies and special materials development. Oak Ridge National Laboratory (ORNL) has developed two-stage guns that accelerate small projectiles (4-mm nominal diameter) to velocities of up to ∼5 km/s. These guns are relatively small and simple (thus, easy to operate), allowing a significant number of test shots to be carried out and data accumulated in a short time. Materials that have been used for projectiles include plastics, frozen isotopes of hydrogen, and lithium hydride. One gun has been used to demonstrate repetitive operation at a rate of 0.7 Hz; and, with a few design improvements, it appears capable of performing at firing frequencies of 1--2 Hz. A schematic of ORNL two-stage device is shown below. Unlike most such devices, no rupture disks are used. Instead, a fast valve (high-flow type) initiates the acceleration process in the first stage. Projectiles can be loaded into the gun breech via the slide mechanism; this action has been automated which allows repetitive firing. Alternatively, the device is equipped with ''pipe gun'' apparatus in which gas can be frozen in situ in the gun barrel to form the projectile. This equipment operates with high reliability and is well suited for small-scale testing at high velocity. 17 refs., 6 figs., 2 tabs

  19. Correlates of Gun Involvement and Aggressiveness among Adolescents.

    Science.gov (United States)

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

    2002-01-01

    Investigated adolescents' aggressiveness in relation to their experiences, beliefs, and attitudes concerning gun use, also noting family composition, relationships with parents, and emotionality as correlates of gun involvement and aggression. Student surveys indicated links between gun ownership and recreational use, beliefs about gun use, and…

  20. Ready, Fire, Aim: The College Campus Gun Fight

    Science.gov (United States)

    Birnbaum, Robert

    2013-01-01

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

  1. Gun Safety Management with Patients at Risk for Suicide

    Science.gov (United States)

    Simon, Robert I.

    2007-01-01

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

  2. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2001-10-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

  3. HIGH VELOCITY THERMAL GUN FOR SURFACE PREPARATION AND TREATMENT

    Directory of Open Access Journals (Sweden)

    I.A. Gorlach

    2012-01-01

    Full Text Available Many surface preparation and treatment processes utilise compressed air to propel particles against surfaces in order to clean and treat them. The effectiveness of the processes depends on the velocity of the particles, which in turn depends on the pressure of the compressed air. This paper describes a thermal gun built on the principles of High Velocity Air Fuel (HVAF and High Velocity Oxy Fuel (HVOF processes. The designed apparatus can be used for abrasive blasting, coating of surfaces, cutting of rocks, removing rubber from mining equipment, cleaning of contaminations etc.

  4. Texas youth stage rally against guns

    Institute of Scientific and Technical Information of China (English)

    Mary; Alice; Robbins; 李小平

    2000-01-01

    Young Texans Against Gun Violence rallied atthe State Capitol on Monday and called for the Legisla-ture to pass laws that would make it more difficult toget guns.“It is time for our state Legislature to pass laws tohelp protect us,”Marianne Moreno,a high school se-nior from the Dallas area,told a crowd of about 125students who attended the“Packing Peace Rally.”“As Texas law stands today,anyone—even acriminal—can walk into a gun show and purchase asemi-automatic weapon or any other type of firearm,...

  5. Advances in DC photocathode electron guns

    International Nuclear Information System (INIS)

    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 back-bombardment, 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. Advances in DC photocathode electron guns

    International Nuclear Information System (INIS)

    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 throughput. 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, we will review recent results and discuss implications for future photocathode guns. copyright 1999 American Institute of Physics

  7. Field reversal produced by a plasma gun

    International Nuclear Information System (INIS)

    Experimental results are presented of the production of Field-Reversed Plasma with a high energy coaxial plasma gun. The gun is magnetized with solenoids inside the center electrode and outside the outer electrode so that plasma emerging from the gun entrains the radial fringer field at the muzzle. The plasma flow extends field lines propagating a high electrical conductivity, the flux inside the center electrode should be preserved. However, for low flux, the trapped flux exceeds by 2 or more the initial flux, possibly because of helical deformation of the current channel extending from the center electrode

  8. Evaluation of Smart Gun Technologies preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, D.R.

    1996-01-01

    The Smart Gun Technology Project has a goal to eliminate the capability of an unauthorized user from firing a law enforcement officer`s firearm by implementing {open_quote}smart{close_quote} technologies. Smart technologies are those that can in some manner identify an officer. This report will identify, describe, and grade various technologies as compared to the requirements that were obtained from officers. This report does not make a final recommendation for a smart gun technology, nor does it give the complete design of a smart gun system.

  9. Serious childhood injuries caused by air guns.

    OpenAIRE

    Shanon, A; Feldman, W.

    1991-01-01

    OBJECTIVE: To determine the severity of nonfatal injuries to children caused by air guns and pellet guns. DESIGN: Case series (hospital chart review). SETTING: Inpatient wards of the Children's Hospital of Eastern Ontario. PATIENTS: All children under 18 years of age admitted to the hospital from Jan. 1, 1979, to Dec. 31, 1989, under ICD code E917, E922, E955, E965, E970 or E985 who had suffered air gun injuries. MAIN OUTCOME MEASURES: Personal data, circumstances of event and clinical data. ...

  10. Advances in DC photocathode electron guns

    International Nuclear Information System (INIS)

    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 throughput. 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, we will review recent results and discuss implications for future photocathode guns

  11. "Is there a gun in the home?" Assessing the risks of gun ownership in older adults.

    Science.gov (United States)

    Pinholt, Ellen M; Mitchell, Joshua D; Butler, Jane H; Kumar, Harjinder

    2014-06-01

    An important ethical and safety concern that geriatricians, primary care providers, and home health professionals need to address is gun ownership by elderly adults. Those aged 65 and older now have the highest rate of gun ownership in America, and they also have a high prevalence of depression and suicide. Dementia can add additional layers of risk. Even older gun owners who are otherwise intellectually intact may benefit from information about gun safety with the increasing numbers of children being cared for by grandparents. Health professionals should ask patients, "Is there a gun in the home?" in the clinic and during home visits. Healthcare professionals must have knowledge and skills to address safe gun ownership in elderly adults. The 5 L's (Locked, Loaded, Little children, feeling Low, Learned owner) will assist professionals in addressing all aspects of safe ownership. PMID:24898055

  12. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, HVLP COATING EQUIPMENT, SHARPE MANUFACTURING COMPANY PLATINUM 2012 HVLP SPRAY GUN

    Science.gov (United States)

    This report presents the results of the verification test of the Sharpe Platinum 2013 high-volume, low-pressure gravity-feed spray gun, hereafter referred to as the Sharpe Platinum, which is designed for use in automotive refinishing. The test coating chosen by Sharpe Manufacturi...

  13. Study of the electrical signals observed during the initial stage in a coaxial gun

    International Nuclear Information System (INIS)

    In this work high frequency oscillations further experimental data, along with its theoretical modeling will be given for initial phase in a coaxial gun constructed to be used in technological applications of plasma. Particular attention was devoted to find any dependence between the measured frequencies and the operating pressure and voltage. 1 ref., 1 fig., 1 tab

  14. On Internal Ballistics of H/L Gun During Burning with Composite Charges

    Directory of Open Access Journals (Sweden)

    R. N. Bhattacharyya

    1975-01-01

    Full Text Available An attempt has been made to solve the internal ballistics of H/L gun with composite charge having two components assuring pressures in both the chambers during the second stage of burning i.e. after the burning of the first component charge.

  15. PART II. HYDRATED CEMENTS

    Directory of Open Access Journals (Sweden)

    Milan Drabik

    2014-09-01

    Full Text Available Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of decompositions - ΔH, of technological materials based on two types of Portland cements. The values of thermoanalytical events and also ΔH of probes of technological compositions, if related with the data of a choice of minerals of calcium-silicate-sulfate-aluminate hydrates, served as a valued input for the assessment of phases present and phase changes due to the topical hydraulic processes. The results indicate mainly the effects of "standard humidity" or "wet storage" of the entire hydration/hydraulic treatment, but also the presence of cement residues alongside calcium-silicate-sulfate-aluminate hydrates (during the tested period of treatment. "A diluting" effect of unhydrated cement residues upon the values of decomposition enthalpies in the studied multiphase system is postulated and discussed

  16. Rail gun powered by an integral explosive generator

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-01-01

    We propose the use of a rail gun powered by an explosive magnetic flux compression generator built into the rail gun itself in which the rails of the gun are driven together behind the projectile by explosives. The magnetic field established between the rails by an initial current supplied by an external source at the breech of the gun is trapped and compressed by the collapsing rails to accelerate the projectile down the bore of the gun.

  17. Durability of pulp fiber-cement composites

    Science.gov (United States)

    Mohr, Benjamin J.

    Wood pulp fibers are a unique reinforcing material as they are non-hazardous, renewable, and readily available at relatively low cost compared to other commercially available fibers. Today, pulp fiber-cement composites can be found in products such as extruded non-pressure pipes and non-structural building materials, mainly thin-sheet products. Although natural fibers have been used historically to reinforce various building materials, little scientific effort has been devoted to the examination of natural fibers to reinforce engineering materials until recently. The need for this type of fundamental research has been emphasized by widespread awareness of moisture-related failures of some engineered materials; these failures have led to the filing of national- and state-level class action lawsuits against several manufacturers. Thus, if pulp fiber-cement composites are to be used for exterior structural applications, the effects of cyclical wet/dry (rain/heat) exposure on performance must be known. Pulp fiber-cement composites have been tested in flexure to examine the progression of strength and toughness degradation. Based on scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), a three-part model describing the mechanisms of progressive degradation has been proposed: (1) initial fiber-cement/fiber interlayer debonding, (2) reprecipitation of crystalline and amorphous ettringite within the void space at the former fiber-cement interface, and (3) fiber embrittlement due to reprecipitation of calcium hydroxide filling the spaces within the fiber cell wall structure. Finally, as a means to mitigate kraft pulp fiber-cement composite degradation, the effects of partial portland cement replacement with various supplementary cementitious materials (SCMs) has been investigated for their effect on mitigating kraft pulp fiber-cement composite mechanical property degradation (i.e., strength and toughness

  18. Technology Roadmaps: Cement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    To support its roadmap work focusing on key technologies for emissions reductions, the International Energy Agency (IEA) also investigated one particular industry: cement. Cement production includes technologies that are both specific to this industry and those that are shared with other industries (e.g., grinding, fuel preparation, combustion, crushing, transport). An industry specific roadmap provides an effective mechanism to bring together several technology options. It outlines the potential for technological advancement for emissions reductions in one industry, as well as potential cross-industry collaboration.

  19. Concrete = aggregate, cement, water?

    International Nuclear Information System (INIS)

    Concrete for the Temelin nuclear power plant is produced to about 70 different formulae. For quality production, homogeneous properties of aggregates, accurate proportioning devices, technological discipline and systematic inspections and tests should be assured. The results are reported of measuring compression strength after 28 days for different concrete samples. The results of such tests allow reducing the proportion of cement, which brings about considerable savings. Reduction in cement quantities can also be achieved by adding ash to the concrete mixes. Ligoplast, a plasticizer addition is used for improving workability. (M.D). 8 figs

  20. Cementing a wellbore using cementing material encapsulated in a shell

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Spadaccini, Christopher M.; Cowan, Kenneth Michael

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  1. The mechanical effect of the existing cement mantle on the in-cement femoral revision.

    LENUS (Irish Health Repository)

    Keeling, Parnell

    2012-08-01

    Cement-in-cement revision hip arthroplasty is an increasingly popular technique to replace a loose femoral stem which retains much of the original cement mantle. However, some concern exists regarding the retention of the existing fatigued and aged cement in such cement-in-cement revisions. This study investigates whether leaving an existing fatigued and aged cement mantle degrades the mechanical performance of a cement-in-cement revision construct.

  2. Magnetic Bubble Expansion Experimental Investigation Using a Compact Coaxial Magnetized Plasma Gun

    Science.gov (United States)

    Zhang, Yue; Lynn, Alan; Hsu, Scott; Li, Hui; Liu, Wei; Gilmore, Mark; Watts, Christopher

    2009-11-01

    The poster will first discuss the construction and improved design of a compact coaxial magnetized plasma gun. The plasma gun is used for experimental studies of magnetic bubble expansion into a lower pressure background plasma, which as a model for extragalactic radio lobes and solar coronal mass ejections. In this experiment, the plasma bubble's density, electron temperature, and propagation speed are measured by using a multiple-tipped langmuir probe. Also a three axis B-dot probe array is used to measure the magnetic field in three dimensions during the expansion process. In this poster experiment setup and data will be provided. Finally the comparison with the simulation result will be made.

  3. Experiments on a gas gun for target injection in inertial fusion energy

    International Nuclear Information System (INIS)

    Projectile-shooting experiments using a simple gas gun were carried out to address issues in target injection technology for fast-ignition-type inertial fusion energy. The gas gun consisted of a high-pressure gas reservoir, quick solenoid valve, and smooth-bore acceleration tube. Simple cylindrical projectiles were accelerated at room temperature by nitrogen gas and shot into a diagnostic chamber. In these experiments, we measured the flight speed, direction, and attitude of projectiles of different lengths. Longer projectiles showed better flight performance. (author)

  4. High voltage test of the 2nd 500 kV DC-gun for ERL

    International Nuclear Information System (INIS)

    A high voltage and vacuum test of the second 500 kV DC-gun was carried out at KEK. Some problems happened in high voltage conditioning processes during a year. We dealt with these problems carefully or easy way in some cases, then we can hold 500 kV in stable more than 50 hours after 550 kV conditioning process. As for the preliminary vacuum test, a pressure of the gun was obtained 4E-10 Pa by using NEG pumps and a bakeable cryopump. (author)

  5. Waterfowl habitat survey : Canvasback Gun Club : 1965

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a survey of the submergent and emergent aquatics growing in the marsh on the Canvasback Gun Club in Nevada. As stated in previous years of...

  6. Waterfowl habitat survey : Canvasback Gun Club : 1963

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a survey of the submergent and emergent aquatics growing in the marsh on the Canvasback Gun Club in Nevada. The marsh portion of the...

  7. Ballistic Rail Gun Soft Recovery Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Ballistic Rail Gun Soft Recovery Facility accommodates a 155mm Howitzer, fired horizontally into a 104-foot long water trough to slow the projectile and recover...

  8. Waterfowl habitat survey : Canvasback Gun Club : 1964

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes a survey of the submergent and emergent aquatics growing in the marsh on the Canvasback Gun Club in Nevada. The marsh portion of the...

  9. Waterfowl habitat survey : Canvasback Gun Club : 1972

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Since the last vegetative survey in 1965, the marsh at Canvasback Gun Club has remained virtually unchanged. The ArthurJohnson Ponds produced most of the waterfowl...

  10. Uudised : Guns N' Roses Soomes. Valmis ulmeraadio

    Index Scriptorium Estoniae

    2006-01-01

    Ameerika hard-rock-bändi Guns N' Roses kontserdist 5. juulil Hartwall Areenal Soomes. Kord kuus on Ulmeplaatide kodulehekülel www. ulmeplaadid.ee võimalus kuulata ulmeraadiot, kus esitusel eesti kergemuusika

  11. RF Electron Gun with Driven Plasma Cathode

    CERN Document Server

    Khodak, Igor

    2005-01-01

    It's known that RF guns with plasma cathodes based on solid-state dielectrics are able to generate an intense electron beam. In this paper we describe results of experimental investigation of the single cavity S-band RF gun with driven plasma cathode. The experimental sample of the cathode based on ferroelectric ceramics has been designed. Special design of the cathode permits to separate spatially processes of plasma development and electron acceleration. It has been obtained at RF gun output electron beam with particle energy ~500 keV, pulse current of 4 A and pulse duration of 80 ns. Results of experimental study of beam parameters are referred in. The gun is purposed to be applied as the intense electron beam source for electron linacs.

  12. Arc Plasma Gun With Coaxial Powder Feed

    Science.gov (United States)

    Zaplatynsky, Isidor

    1988-01-01

    Redesigned plasma gun provides improved metallic and ceramic coatings. Particles injected directly through coaxial bore in cathode into central region of plasma jet. Introduced into hotter and faster region of plasma jet.

  13. Waterfowl habitat survey : Canvasback Gun Club : 1962

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is about an investigation that was done to determine the quantity and species of submergent vegetation in the marsh area on the Canvasback Gun Club in...

  14. Computational studies of two-phase cement-CO2-brine interaction in wellbore environments

    Energy Technology Data Exchange (ETDEWEB)

    Carey, James William [Los Alamos National Laboratory; Lichtner, Peter C [Los Alamos National Laboratory

    2009-01-01

    Wellbore integrity is essential to ensuring long-term isolation of buoyant supercritical CO{sub 2} during geologic sequestration of CO{sub 2}. In this report, we summarize recent progress in numerical simulations of cement-brine-CO{sub 2} interactions with respect to migration of CO{sub 2} outside of casing. Using typical values for the hydrologic properties of cement, caprock (shale) and reservoir materials, we show that the capillary properties of good quality cement will prevent flow of CO{sub 2} into and through cement. Rather, CO{sub 2}, if present, is likely to be confined to the casing-cement or cement-formation interfaces. CO{sub 2} does react with the cement by diffusion from the interface into the cement, in which case it produces distinct carbonation fronts within the cement. This is consistent with observations of cement performance at the CO{sub 2}-enhanced oil recovery SACROC Unit in West Texas (Carey et al. 2007). For poor quality cement, flow through cement may occur and would produce a pattern of uniform carbonation without reaction fronts. We also consider an alternative explanation for cement carbonation reactions as due to CO{sub 2} derived from caprock. We show that carbonation reactions in cement are limited to surficial reactions when CO{sub 2} pressure is low (< 10 bars) as might be expected in many caprock environments. For the case of caprock overlying natural CO{sub 2} reservoirs for millions of years, we consider Scherer and Huet's (2009) hypothesis of diffusive steady-state between CO{sub 2} in the reservoir and in the caprock. We find that in this case, the aqueous CO{sub 2} concentration would differ little from the reservoir and would be expected to produce carbonation reaction fronts in cements that are relatively uniform as a function of depth.

  15. In-vitro study of resin-modified glass ionomer cements for cementation of orthodontic bands. Isolation, surplus removal and humidity as factors influencing the bond strength between enamel, cement and metal.

    Science.gov (United States)

    Liebmann, S M; Jost-Brinkmann, P G

    1999-01-01

    The aim of this in vitro study was to investigate different light-cured and chemically cured resin-modified glass ionomer cements used for the cementation of orthodontic bands and to analyze various factors influencing the adhesive strength between enamel, cement and stainless steel. Four resin-modified glass ionomers (Fuji Ortho LC/GC, Fuji Duet/GC, Unitek Multi-Cure Glass Ionomer Orthodontic Band Cement/3M Unitek, Vitremer/3M) and 1 compomer (Band-Lok/Reliance) were examined. Flattened and polished bovine teeth embedded in polyurethane resin were used as enamel specimens. Before cementation, 50% of the specimens were moistened with the aerosol of an inhalation device, while the rest were dried with compressed air. Stainless steel cylinders (CrNi 18 10) were perpendicularly bonded onto the polished enamel using a custom-made cementation device and immediately topped with a pressure of 0.25 MPa. The cement was isolated with either Ketac Glaze/ESPE, Fuji Coat/GC, Cacao Butter/GC, Dryfoil/Jalenko or Final Varnish/VOCO, or was left uncoated. Eight minutes after the beginning of mixing, either the surplus cement was removed with a scalpel or surplus removal was simulated with ultrasound. After 24 hours storage in a water bath at 37 degrees C and 1,000 thermocycles the shear bond strength was determined. Significant differences with respect to the shear bond strength were found among the following cements, ranking from highest to lowest: Fuji Duet, Unitek cement > Fuji Ortho LC > Vitremer > Band-Lok. The application of a barrier coating significantly increased the shear bond strength of all cements except Fuji Ortho LC. The light-cured resin Ketac Glaze proved to be the most effective barrier coating. A dry enamel surface increased the bond strength of all investigated cements except Unitek cement. The use of ultrasound led to no significant reduction in shear bond strength in comparison with surplus removal with a scalpel. PMID:10546417

  16. Conference on electromagnetic guns and launchers, 1980

    International Nuclear Information System (INIS)

    Proceedings includes 31 papers dealing with the physical principles and engineering technology associated with the development of electromagnetic propulsion, with emphasis on its use for guns, launchers as well as other military equipment. Topics covered include: rail guns, projectiles, mass accelerators, electric motors and generators, nuclear reactors, superconducting devices, plasma acceleration and confinement, traveling magnetic waves, aerospace propulsion, space shuttles, homopolar generators, fusion reactors, tokamaks, impact fusion, and electric power generation. All papers are abstracted and indexed separately

  17. The Impact of Banning Juvenile Gun Possession.

    OpenAIRE

    Thomas B. Marvell

    2001-01-01

    A 1994 federal law bans possession of handguns by persons under 18 years of age. Also in 1994, 11 states passed their own juvenile gun possession bans. Eighteen states had previously passed bans, 15 of them between 1975 and 1993. These laws were intended to reduce homicides, but arguments can be made that they have no effect on or that they even increase the homicide rate. This paper estimates the laws' impacts on various crime measures, primarily juvenile gun homicide victimizations and suic...

  18. Anti-aircraft Missiles and Gun Control

    OpenAIRE

    BLOCK, Walter

    2016-01-01

    Abstract. Gun control is a highly debatable topic both in the popular and scholarly media. But what about anti-aircraft missiles? Should they be banned? On the one hand, there are fewer of them around, so their challenge is more tractable. On the other hand, they can do far more damage than handguns. The present paper is an attempt to wrestle with this challenge.Keywords. Gun control, Second amendment, Libertarianism, Anti-aircraft missiles.JEL. K15.

  19. Produktie van cement

    NARCIS (Netherlands)

    Smit JRK; Coenen PWHG; Matthijsen AJCM; LAE; TAUW

    1995-01-01

    This document on cement production has been published within the SPIN project. In this project information has been collected on industrial plants or industrial processes to afford support to governmental policy on emission reduction. This document contains information on the processes, emission sou

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

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, Lloyd Lee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bartram, Brian Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dattelbaum, Dana Mcgraw [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lang, John Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Morris, John Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-01

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

  1. Changes to the LANL gas-driven two-stage gun: Magnetic gauge instrumentation, etc.

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

    Our gas-driven two-stage gun was designed and built to do initiation studies on insensitive high explosives as well as other equation of state experiments on inert materials. Our preferred method of measuring initiation phenomena involves the use of magnetic particle velocity gauges. In order to accommodate this type of gauging in our two-stage gun, projectile velocity was sacrificed in favor of a larger experimental target area (obtained by using a 50 mm diameter launch tube). We have used magnetic gauging on our 72-mm bore diameter single-stage gun for over 15 years and it has proven a very effective technique to monitor reactive shock wave evolution. This technique has now been adapted to our gas-driven two-stage gun. We describe the method used, as well as some of the difficulties that arose while installing this technique. Several magnetic gauge experiments have been completed on plastic materials. Waveforms obtained in one experiment are given, along with the Hugoniot information that was obtained. This new technique is now working quite well, as is evidenced by the data. To our knowledge, this is the first time magnetic gauging has been used on a two-stage gun. We have also made changes to the burst diaphragm package in the transition section to ensure that the petals do not break off during the opening process and to increase the burst pressure. This will also be discussed briefly.

  2. Reactive-Transport Model of Buffer Cementation

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Randy; Wei Zhou [Monitor Scientific LLC, Denver, CO (United States)

    2005-10-15

    Thermal gradients during the early, non-isothermal period of near-field evolution in a KBS-3 repository for spent nuclear fuel could alter the mineralogy of the bentonite buffer and cause the constituent clay particles to become cemented together by mineral precipitates. Cementation is a potential concern because it could alter the ductility, mechanical strength and swelling pressure of the buffer, thereby possibly adversely affecting the primary performance function of this key barrier to provide a stable diffusional transport pathway between the canister and rock. The present study uses the TOUGHREACT computer program to simulate reactive-transport processes that are thought to control buffer cementation. TOUGHREACT is generally applicable to problems involving non-isothermal, multiphase reactive transport in variably saturated media. For cementation problems, the modeling approach must account specifically for the temperature dependence of equilibrium and kinetic constraints on dissolution/precipitation reactions involving the primary smectite clays and accessory phases in bentonite, and for diffusive transport of aqueous reactants and products along concentration gradients that are aligned with, or in opposition to, the direction of decreasing temperatures across the near field. The modeling approach was evaluated in two stages. A conceptual model of buffer cementation was first calibrated using observations from field tests carried out at the Stripa mine and Aespoe HRL (LOT pilot experiments). The calibrated model was then used to simulate the geochemical evolution of the KBS-3 buffer during the non-isothermal period of repository evolution. This model accounts for the imbibition of groundwater from a granitic host rock into initially unsaturated buffer materials under capillary and hydraulic pressure gradients, and uses realistic time-temperature constraints on the thermal evolution of the near-field. Preliminary results suggest that the total extent of

  3. Reactive-Transport Model of Buffer Cementation

    International Nuclear Information System (INIS)

    Thermal gradients during the early, non-isothermal period of near-field evolution in a KBS-3 repository for spent nuclear fuel could alter the mineralogy of the bentonite buffer and cause the constituent clay particles to become cemented together by mineral precipitates. Cementation is a potential concern because it could alter the ductility, mechanical strength and swelling pressure of the buffer, thereby possibly adversely affecting the primary performance function of this key barrier to provide a stable diffusional transport pathway between the canister and rock. The present study uses the TOUGHREACT computer program to simulate reactive-transport processes that are thought to control buffer cementation. TOUGHREACT is generally applicable to problems involving non-isothermal, multiphase reactive transport in variably saturated media. For cementation problems, the modeling approach must account specifically for the temperature dependence of equilibrium and kinetic constraints on dissolution/precipitation reactions involving the primary smectite clays and accessory phases in bentonite, and for diffusive transport of aqueous reactants and products along concentration gradients that are aligned with, or in opposition to, the direction of decreasing temperatures across the near field. The modeling approach was evaluated in two stages. A conceptual model of buffer cementation was first calibrated using observations from field tests carried out at the Stripa mine and Aespoe HRL (LOT pilot experiments). The calibrated model was then used to simulate the geochemical evolution of the KBS-3 buffer during the non-isothermal period of repository evolution. This model accounts for the imbibition of groundwater from a granitic host rock into initially unsaturated buffer materials under capillary and hydraulic pressure gradients, and uses realistic time-temperature constraints on the thermal evolution of the near-field. Preliminary results suggest that the total extent of

  4. Multiphase CFD Simulation of Solid Propellant Combustion in a Small Gun Chamber

    OpenAIRE

    Ahmed Bougamra; Huilin Lu

    2014-01-01

    The interior ballistics simulations in 9 mm small gun chamber were conducted by implementing the process into the mixture multiphase model of Fluent V6.3 platform. The pressure of the combustion chamber, the velocity, and the travel of the projectile were investigated. The performance of the process, namely, the maximum pressure, the muzzle velocity, and the duration of the process was assessed. The calculation method is validated by the comparison of the numerical simulations results in the ...

  5. Study on a coaxial plasma gun: pt. III

    International Nuclear Information System (INIS)

    A Mather type plasms gun is operated at below l torr with an energy storage system (4KJ, 16.5KV, 35nH) to study the conditions of the efficient plasma focus. When the D2 gas filling pressure is 0.18 torr and the stored energy is 3.8KJ, the discharge current of max. 180KA is obtained and the average axial velocity of the plasma is about 7cm/μs. This is lower than the calculated velocity with above conditions by the snow-plow model. The discrepancy is due to the currents flowing over the insulator surface. The plasma focus occurs at low pressure compared with the results obtained by Bruzzone. The reasons are such that the plasma gun employed in this experiment is large for the stored energy and the concentration of the residual gas is comparatively high. It is confirmed by a Long counter that the neutrons are generated from the dense plasma focus. (author)

  6. Blower Gun pellet injection system for W7-X

    International Nuclear Information System (INIS)

    Foreseen to serve for the new stellarator W7-X for pellet investigations, the former ASDEX Upgrade Blower Gun was revised and revitalized in a test bed. The gun is able now to launch cylindrical pellets of 2 mm diameter and 2 mm length, produced from frozen Deuterium (D2) or Hydrogen (H2). Pellets are accelerated by a short pulse of pressurized helium propellant gas to velocities in the range of 100-250 m/s. Delivery reliabilities at the launcher exit close to unity are achieved. For pellet transfer to the plasma vessel a first mock up guiding tube version was investigated. Transfer through this S-shaped (inner diameter 8 mm; length 6 m) stainless steel guiding tube containing two 1 m curvature radii was investigated for both H2 and D2 pellets. Tests were performed applying repetition rates from 2 Hz to 50 Hz and propellant gas pressures ranging from 1 bar to 6 bar. For both H2 and D2, low overall delivery efficiencies were observed at slow repetition rates, but stable efficiencies of about 90% above 10 Hz.

  7. Gun Carrying by High School Students in Boston, MA: Does Overestimation of Peer Gun Carrying Matter?

    Science.gov (United States)

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

    2011-01-01

    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 1700 high school students in Boston, MA. Over 5% of students reported carrying a…

  8. The supply and demand for guns to juveniles: Oakland's gun tracing project.

    Science.gov (United States)

    Calhoun, Deane; Dodge, Andrea Craig; Journel, Coraline S; Zahnd, Elaine

    2005-12-01

    In response to Oakland, California's high level of gun violence affecting young people, the East Oakland Partnership to Reduce Juvenile Gun Violence, a citywide collaboration, was formed in 1997. In 1999, the Partnership established the Oakland Gun Tracing Project to develop evidence-based policy recommendations aimed at reducing the supply of and demand for gun acquisition among urban youth. The advocacy project involved gathering, analyzing, and using police record and gun sale/registration data to inform policy and practice. Such data were collected for all gun crimes committed in Oakland, California between 1998 and 1999 in which a juvenile was either the suspect or the victim. The 213 cases involved 263 juveniles of which 170 were suspects/perpetrators and 93 were victims. Suspects as well as victims were predominantly male and African American. The 213 cases involved 132 recovered guns. Only 55% of the cases were traced to a federally licensed dealer. Three-quarters of the guns were purchased near Oakland, California. Successful traces, defined as the ability to identify federally licensed dealers and initial purchasers, were completed on only 52 of the 132 guns, demonstrating systemic tracing difficulties. Data gathered for the project was used to advocate for numerous policy changes. Recommended policy strategies include initiating a comprehensive gun tracing program so police can track all secondary sales, new laws requiring federal handgun registration which would track ownership changes, required reporting of stolen firearms, and providing effective intervention services to all juveniles the first time they enter the criminal justice system. PMID:16269532

  9. Release isentrope measurements with the LLNL electric gun

    Energy Technology Data Exchange (ETDEWEB)

    Gathers, G.R.; Osher, J.E.; Chau, H.H.; Weingart, R.C.; Lee, C.G.; Diaz, E.

    1987-06-01

    The liquid-vapor coexistence boundary is not well known for most metals because the extreme conditions near the critical point create severe experimental difficulties. The isentropes passing through the liquid-vapor region typically begin from rather large pressures on the Hugoniot. We are attempting to use the high velocities achievable with the Lawrence Livermore National Laboratory (LLNL) electric gun to obtain these extreme states in aluminum and measure the release isentropes by releasing into a series of calibrated standards with known Hugoniots. To achieve large pressure drops needed to explore the liquid-vapor region, we use argon gas for which Hugoniots have been calculated using the ACTEX code, as one of the release materials.

  10. Role of Substrate on Quartz Cementation in Quartz Aggregates

    Science.gov (United States)

    Farver, J. R.; Winslow, D.; Onasch, C.

    2010-12-01

    Quartz cementation in quartz aggregates has been experimentally investigated. The starting material was disaggregated detrital quartz grains from the well-sorted, mature St. Peter Sandstone. The ‘as-is’ grains have patches of iron oxide coatings and some have euhedral overgrowths that contain iron oxide dust rims. In addition a set of experiments was run using grains that were cleaned by soaking in sodium hydrosulfite and sodium bisulfate solutions to remove exposed iron oxide coatings. Experimental charges consisted of amorphous silica powder (≈30 mg) to provide a source of silica for the quartz cement, AlCl3 powder (≈3 mg) to provide a tracer for Cathodoluminescence (CL) identification of cement formed during the experiment, 25 wt% NaCl brine solution (≈25 mg) to increase the silica solubility and to better mimic oil field brines, and the natural quartz grains (100-130 mg). The charges were weld-sealed in Au capsules and run in cold-seal pressure vessels at 250°C to 450°C at 150 MPa confining pressure for up to 8 weeks. After the experiments, the samples were vacuum impregnated with a low viscosity epoxy containing a blue dye. After curing, the sample charge was sawn in half along its long axis and one half was polished (to 1 micron diamond paste) for analysis. The nature and amount of quartz cement in the samples were determined by a combination of CL, light microscopy, and scanning electron microscopy. Photomosaics of the samples were created and the amount of cement, porosity, and average grain sizes were determined by point-counting. The cement formed during the experiment was easily recognized from the quartz grains (and previous overgrowths) by the difference in luminescence. The results indicate the amorphous silica powder provides a ready source for silica for quartz cementation due to its greater solubility than the quartz. The cementation rates are rapid (>14% cement formed in 2 weeks at 450°C and >7% in 8 weeks at 250°C). Compared to

  11. Characterisation and modelling of blended cements and their application to radioactive waste immobilisation

    International Nuclear Information System (INIS)

    Various aspects of the chemistry of cements, including blends with FA and BFS, pertinent to the immobilization of radioactive waste are described. The methodology and development of a model for predicting the solid and liquid phase composition in aged cement blends are given. Experimental work, backed up by thermodynamic calculations (where possible), has given valuable insight into some of the important interactions between selected (active and inactive) radwaste components and cements. The effects of elevated pressure and temperature on blended cement are also investigated. (author)

  12. US cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Nisbet, M.A.

    1997-12-31

    This paper describes the cement and concrete industry, and provides data on energy use and carbon dioxide emissions. The potential impact of an energy tax on the industry is briefly assessed. Opportunities identified for reducing carbon dioxide emissions include improved energy efficiency, alternative fuels, and alternative materials. The key factor in determining CO{sub 2} emissions is the level of domestic production. The projected improvement in energy efficiency and the relatively slow growth in domestic shipments indicate that CO{sub 2} emissions in 2000 should be about 5% above the 1990 target. However, due to the cyclical nature of cement demand, emissions will probably be above target levels during peak demand and below target levels during demand troughs. 7 figs., 2 tabs.

  13. A high-brightness thermionic microwave electron gun

    International Nuclear Information System (INIS)

    In a collaborative effort by SSRL, AET Associates, and Varian Associates, a high-brightness microwave electron gun using a thermionic cathode has been designed, built, tested, and installed for use with the SSRL 150 MeV linear accelerator. This thesis discusses the physics behind the design and operation of the gun and associated systems, presenting predictions and experimental tests of the gun's performance. The microwave gun concept is of increasing interest due to its promise of providing higher-current, lower-emittance electron beams than possible from conventional, DC gun technology. In a DC guns, accelerating gradients are less than 8 MV/m, while those in a microwave gun can exceed 100 MV/m, providing much more rapid initial acceleration, thereby reducing the deleterious effects of space-charge. Microwave guns produce higher momentum beams than DC guns, thus lessening space-charge effects during subsequent beam transport. Typical DC guns produce kinetic energies of 80--400 KeV, compared to 2--3 MeV for the SSRL microwave gun. ''State-of-the-art'' microwave gun designs employ laser-driven photocathodes, providing excellent performance but with greater complexity and monetary costs. A thermionic microwave gun with a magnetic bunching system is comparable in cost and complexity to a conventional system, but provides performance that is orders of magnitude better. Simulations of the SSRL microwave gun predict a normalized RMS emittance at the gun exist of ec · μm for a beam consisting of approximately 50% of the particles emitted from the gun, and having a momentum spread ±10%. These emittances are for up to 5 x 109e- per bunch. Chromatic aberrations in the transport line between the gun and linear accelerator increase this to typically e · μm

  14. Higher-order mode rf guns

    Science.gov (United States)

    Lewellen, John W.

    2001-04-01

    Traditional photocathode rf gun design is based around the use of TM0,1,0-mode cavities. This is typically done in the interest of obtaining the highest possible gradient per unit supplied rf power and for historical reasons. In a multicell, aperture-coupled photoinjector, however, the gun as a whole is produced from strongly coupled cavities oscillating in a π mode. This design requires very careful preparation and tuning, as the field balance and resonant frequencies are easily disturbed. Side-coupled designs are often avoided because of the dipole modes introduced into the cavity fields. This paper proposes the use of a single higher-order mode rf cavity in order to generate the desired on-axis fields. It is shown that the field experienced by a beam in a higher-order mode rf gun is initially very similar to traditional 1.5- or 2.5-cell π-mode gun fields, and projected performance in terms of beam quality is also comparable. The new design has the advantages of much greater ease of fabrication, immunity from coupled-cell effects, and simpler tuning procedures. Because of the gun geometry, the possibility also exists for improved temperature stabilization and cooling for high duty-cycle applications.

  15. ECR ion source with electron gun

    Science.gov (United States)

    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.

  16. Progress of the Rossendorf SRF Gun Project

    CERN Document Server

    Teichert, J; Büttig, H; Janssen, D; Lehnert, U; Michel, P; Möller, K; Murcek, P; Schneider, C; Schurig, R; Staufenbiel, F; Xiang, R

    2005-01-01

    A superconducting rf photo electron injector (SRF gun) is under development at the Forschungszentrum Rossendorf. The project aims at several issues: improvement of the beam quality for the ELBE superconducting electron linac, demonstration of feasibility of this gun type, investigation of critical components, and parameter studies for future application (BESSY-FEL, 4GLS). In 2005, a substantial progress has been made. The two 3.5-cell niobium cavities for the gun have been delivered from the company ACCEL. The main parts for gun cryostat like vacuum vessel, cryogenic and magnetic shields are ready. Test benches for the cathode cooling system and the cavity tuner are being assembled. The photo cathode preparation lab has been arranged, and the diagnostic beam line has been designed (see T. Kamps et al., this conference). After delivering the gun cavities, their rf properties are being measured at room temperature and the warm tuning is being carried out. The set-up for this treatment and measurement as well as...

  17. Performance of Cement Containing Laterite as Supplementary Cementing Material

    Directory of Open Access Journals (Sweden)

    Abbas Bukhari, Z. S.

    2013-03-01

    Full Text Available The utilization of different industrial waste, by-products or other materials such as ground granulated blast furnace slag, silica fume, fly ash, limestone, and kiln dust, etc. as supplemen- tary cementing materials has received considerable attention in recent years. A study has been conducted to look into the performance of laterite as Supplementary Cementing Materials (SCM. The study focuses on compressive strength performance of blended cement containing different percentage of laterite. The cement is replaced accordingly with percentage of 2 %, 5 %, 7 % and 10 % by weight. In addition, the effect of use of three chemically different laterites have been studied on physical performance of cement as in setting time, Le-Chatlier expansion, loss on ignition, insoluble residue, free lime and specifically compressive strength of cement cubes tested at the age of 3, 7, and 28 days. The results show that the strength of cement blended with laterite as SCM is enhanced. Key words: Portland cement, supplementary cementing materials (SCM, laterite, compressive strength KUI – 6/2013 Received January 4, 2012 Accepted February 11, 2013

  18. 哈萨克斯坦哈德油田低压易漏层防气窜固井工艺%Gas proof cementing technology in low pressure mud loss layer in Hade Oilfield of Kazakhstan

    Institute of Scientific and Technical Information of China (English)

    刘振通; 李冬; 黄志刚; 韩振强; 周冀; 顾永峰

    2009-01-01

    Because of the active gas and oil and the complex formation conditions in Hade Oilfield, gas breakthrough and circulation loss become the primary problems in cementation, which cause the mud shale and gravel layer dropping out and forming an irregular lageniform hole. Logging, electric logging and cementing data of ten typical wells at different times was extracted after getting the bid of cementation in Hade Oilfield. By analyzing and testing these data, cementing techniques of high quality BCS-010L flush fluid, multi-density multi-ladder-type anti-gas condensate expansion cement slurry system and optimized operating parameters were adopted which effectively resolved such problems as mud loss, gas breakthrough and displacement efficiency. With cementing job quality improved noticeably, high grade ratio rose from 37. 5% in 2007 to 81. 8% in 2008, and the new technology will further popularize and be applied in Hade Oilfield.%哈德油田油气活跃,地层条件复杂,气窜和井漏是固井面临的主要难题;泥页岩、砾石层在钻进过程中脱落,形成不规则的"糖葫芦"井眼.渤海钻探工程有限公司第一固井分公司中标哈德油田固井后,提取了以往不同时期典型的10口井的录井、电测和固井资料,经过分析、对比、研究,采用优质的BCS-010L冲洗液、阶梯式多密度多凝膨胀型防气窜水泥浆体系及优化施工参数等固井工艺,有效地解决了固井过程中的漏、窜和顶替效率问题,固井质量有了显著提高,优质率由2007年37.5%提高到了2008年的81.8 %.该技术可在哈德油田进一步推广应用.

  19. Multiphase CFD Simulation of Solid Propellant Combustion in a Small Gun Chamber

    Directory of Open Access Journals (Sweden)

    Ahmed Bougamra

    2014-01-01

    Full Text Available The interior ballistics simulations in 9 mm small gun chamber were conducted by implementing the process into the mixture multiphase model of Fluent V6.3 platform. The pressure of the combustion chamber, the velocity, and the travel of the projectile were investigated. The performance of the process, namely, the maximum pressure, the muzzle velocity, and the duration of the process was assessed. The calculation method is validated by the comparison of the numerical simulations results in the small gun with practical tests, and with lumped-parameter model results. In the current numerical study, both the characteristics and the performance of the interior ballistic process were reasonably predicted compared with the practical tests results. The impact of the weight charge on the interior ballistic performances was investigated. It has been found that the maximum pressure and the muzzle velocity increase with the increase of the charge weight.

  20. Tympanoplasty with ionomeric cement.

    Science.gov (United States)

    Kjeldsen, A D; Grøntved, A M

    2000-01-01

    Patients with isolated erosion of the long incus process suffer from severe hearing loss caused by lack of continuity of the ossicular chain. This study is a retrospective evaluation of the hearing results using two different surgical procedures. Since January 1993, 12 consecutive patients with isolated erosion of the long incus process have been treated with a new surgical technique in which the ossicular chain was rebuilt with ionomeric cement. The results in hearing performance (mean pure-tone average (PTA) 0.5, 1 and 2 kHz) were evaluated pre- and post-surgery, and compared to those in a group of 20 historical controls who underwent surgery in 1991 and 1992 using incus autograft interposition. Among the 12 index patients, 7 (58%) achieved improvement in PTA of > 10 dB, in 3 there was no difference and in 2 a slight decline. Among the 20 controls, 14 (70%) achieved improvement in PTA of > 10 dB, in 4 there was a slight improvement and in 2 a decline. The difference was not statistically significant. Hearing improvement using ionomeric cement in type II tympanoplasty was satisfactory. Reconstruction of the ossicular chain with ionomeric cement is recommended, as the procedure is easy to perform, presents less risk of damage to the stapes and cochlea, requires less extensive surgery and does not exclude other surgical methods in cases of reoperation. PMID:10909000

  1. Barium aluminate cement: its application

    International Nuclear Information System (INIS)

    The technology of manufacturing barium aluminate cement from barium sulfate and alumina, using a rotary kiln for firing the clinker is described. The method of granulation of the homogenized charge was used. Conditions of using the ''to mud'' method in industry were indicated. The physical and chemical properties of barium aluminate cement are determined and the quality of several batches of cement prepared on a semi-industrial scale and their suitability for making highly refractory concretes are tested. The optimal composition of the concretes is determined as a function of the mixing water and barium aluminate cement contents. Several experimental batches of concretes were used in the linings of furnaces in the steel industry. The suitability of these cements for use in fields other than steelmaking is examined. It is established that calcium aluminate cement has certain limited applications

  2. Modeling of propellant flow and explosively-driven valve for the Large-Bore Powder Gun

    Science.gov (United States)

    Lam, Kin

    2013-06-01

    The Large-Bore Powder Gun, with a 3.5-inch bore, is being developed to provide dynamic experiments on physics samples at the Nevada Test Site with impact velocities exceeding 2 km/s. A confinement system is required to seal the target chamber from the gun system to keep it free of hazardous materials from the impact event. A key component of the confinement system is an explosively driven valve (EDV), which uses a small amount of explosive (PBX 9501) to drive an aluminum piston perpendicular to the barrel axis into a tapered hole. The objective of this study is to evaluate the efficacy of the EDV design via computational simulations using models validated with prototype experiments. We first established the gun performance characteristics using an interior ballistics code. Then an energy source model capable of generating the kinematics (i.e., pressure, velocity and displacement profiles) as predicted by the interior ballistic code is used in the hydrodynamics code CTH to calculate the M14 propellant gas expansion as the projectile travels down the gun barrel with the goal of obtaining the lateral (stagnation) pressure load on the EDV piston as it is inserted into the bore. A model of the EDV operation validated against stand-alone experiments is also developed. The gas flow and EDV models are combined to simulate integrated tests as well as the operating conditions specified for qualification. Results from these simulations and those involving design modifications to improve the confinement will be presented.

  3. The Hydration of Blended Cement at Low W/B Ratio

    Institute of Scientific and Technical Information of China (English)

    HU Shu-guang; LU Lin-nu; HE Yong-jia; LI Yue; DING Qing-jun

    2003-01-01

    The hydration process, hydration product and hydration heat of blended cement paste mixed with mineral admixture and expansive agent at low W/B ratio are studied by XRD , thermo analysis , and calorimetry instrument, and they were compared with those of pure cement paste. The results show that pure cement and blended cement at low W/B ratio have the same types of hydration products, but their respective amounts of hydration products of various blended cements at same ages and the vatiation law of the amount of same hydration products with ages are different; Tim joint effect of tumefaction of gel-ettringite due to water absorption and the expansive pressure on the pore and riff caused by the crystalloid ettringite is the impetus of the volume expansion of cement paste , and the former effect is much greater than the latter one .

  4. [Haemotoxicity of dental luting cements].

    Science.gov (United States)

    Anders, A; Welker, D

    1989-06-01

    A glass ionomer luting cement (AquaCem) shows a relatively low haemolytic activity in comparison with two zinc phosphate cements. Especially the initial irritation by this cement is smaller. Although it is possible that AquaCem particularly, in unfavourable cases, may damage the pulpa dentin system; this is due to the slowly decrease of the haemolytic activity with increasing of the probes. We found that Adhesor showed in dependence of the batches a varying quality. PMID:2626769

  5. Cement penetration after patella venting.

    Science.gov (United States)

    Jones, Christopher W; Lam, Li-On; Butler, Adam; Wood, David J; Walsh, William R

    2009-01-01

    There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement. PMID:19010682

  6. [Comparison of wound morphology following gunshots by machine guns and sub-machine guns].

    Science.gov (United States)

    Grellner, W; Madea, B

    1999-01-01

    Automatic weapons such as machine guns and submachine guns are found in the German-speaking region only in special army and police units and appear accordingly rarely in homicides, suicides and accidents. In the following, the findings in two cases of death with the use of machine and submachine guns are presented. The first case was a fatal accident during shooting on a training area (current machine gun of the German army, calibre 7.62 x 51 mm), the second case was a killing during a physical conflict (submachine gun MP 40 from World War II, calibre 9 x 19 mm). In the case with the machine gun autopsy disclosed typical entry holes corresponding to the calibre, but unusually large exit wounds with tissue bridges in the wound ground, measuring 4 x 2.5 cm in diameter. By contrast, the second case (submachine gun) showed "normal" entry and exit wounds. The differences are mainly caused by deviating ballistic data of the ammunition used. They are discussed against the background of literature on wound ballistics. PMID:10198694

  7. Gun Injuries More Often Fatal Now, Study Finds

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_159357.html Gun Injuries More Often Fatal Now, Study Finds ERs ... June 14, 2016 (HealthDay News) -- Injuries from senseless gun violence -- like those witnessed in Orlando on Sunday ...

  8. Gun Injuries More Often Fatal Now, Study Finds

    Science.gov (United States)

    ... nlm.nih.gov/medlineplus/news/fullstory_159357.html Gun Injuries More Often Fatal Now, Study Finds ERs ... June 14, 2016 (HealthDay News) -- Injuries from senseless gun violence -- like those witnessed in Orlando on Sunday ...

  9. The Adhesion and Formation Mechanism of Blast Furnace Gunning Layer

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Basing on the study of the equilibrium relationship of interfacial tension among gunning particles, repaired surface and atmosphere, this test is in a position to draw a conclusion concerning the adhesion mechanism of the gunning refractory and the repaired surface, which illustrates the formation of the bottom gunning layer by moist fine gunning particles on the repaired surface. Also involved within the scope of discussion and probe are the patterns formed under this contacting effect and the formation mechanism of gunning layer. The analytic research regarding the behavior of gunning interface has ascribed the influence upon adhesion intensity to the quality of furnace gunning refractory, the state of the repaired surface and the gunning techniques.

  10. The Real Costs of Gun Violence

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Philip J. (Duke University)

    2001-03-14

    I will report some of the results in my new book, 'Gun Violence: The Real Costs' (Oxford University Press, 2000; with Jens Ludwig). The problem of gun violence is usually summarized by statistics on deaths and injuries. Those statistics tell only part of the story. All of us bear some of the burden of gun violence, at least in the form of higher taxes and waiting to go through the airport security checks. But that's just the beginning. The extraordinary reductions in lethal violence that occurred during the 1990s help account for rising property values and urban renewal; further reductions are possible and would do still more to enhance the average standard of living. This talk will explain why the economic perspective provides a fresh, useful point of view on violence, and will discuss the technique used to arrive at an estimate of the magnitude of the burden.

  11. Secondary emission electron gun using external primaries

    Science.gov (United States)

    Srinivasan-Rao, Triveni; Ben-Zvi, Ilan; Kewisch, Jorg; Chang, Xiangyun

    2007-06-05

    An electron gun for generating an electron beam is provided, which includes a secondary emitter. The secondary emitter includes a non-contaminating negative-electron-affinity (NEA) material and emitting surface. The gun includes an accelerating region which accelerates the secondaries from the emitting surface. The secondaries are emitted in response to a primary beam generated external to the accelerating region. The accelerating region may include a superconducting radio frequency (RF) cavity, and the gun may be operated in a continuous wave (CW) mode. The secondary emitter includes hydrogenated diamond. A uniform electrically conductive layer is superposed on the emitter to replenish the extracted current, preventing charging of the emitter. An encapsulated secondary emission enhanced cathode device, useful in a superconducting RF cavity, includes a housing for maintaining vacuum, a cathode, e.g., a photocathode, and the non-contaminating NEA secondary emitter with the uniform electrically conductive layer superposed thereon.

  12. Improved DC Gun and Insulator Assembly

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. The interaction between potential criminals' and victims' demands for guns

    OpenAIRE

    Baç, Mehmet; Bac, Mehmet

    2009-01-01

    I develop a model with endogenous gun ownership and study the interaction between the demands for guns by heterogeneous potential offenders and victims. I show that the interaction depends on pervasiveness of guns, injury probabilities and, in particular, the impact of the gun on the probability of success against armed relative to unarmed adversaries. While the sanction on armed offense is maximal under plausible conditions, the sanction on unarmed offense balances direct deterrence benef...

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

    OpenAIRE

    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 m...

  15. Development of Electron Guns for Linacs and DC Accelerator

    International Nuclear Information System (INIS)

    Electrons guns for RF linacs and DC Accelerators are designed and developed at Electron Beam Centre (EBC)/APPD/BARC. Planar geometry grid and Pierce geometry grid configuration diode and triode guns with LaB6 cathode are developed. The cathode assembly consists of cups and heat shields made out of Tantalum and Rhenium sheets. The cathode assembly and the electron guns are tested on a test bench for beam characterization. The paper presents the development of the electron guns.

  16. Interpreting the Empirical Evidence on Illegal Gun Market Dynamics

    OpenAIRE

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

    2012-01-01

    Thousands of Americans are killed by gunfire each year, and hundreds of thousands more are injured or threatened with guns in robberies and assaults. The burden of gun violence in urban areas is particularly high. Critics suggest that the results of firearm trace data and gun trafficking investigation studies cannot be used to understand the illegal supply of guns to criminals and, therefore, that regulatory and enforcement efforts designed to disrupt illegal firearms markets are futile in ad...

  17. Dynamic Simulation of the Tank Gun Recoil Response

    Institute of Scientific and Technical Information of China (English)

    XING Jun-wen; WANG Liang-xi; SHI Yan; CHEN Chun-liang

    2005-01-01

    By using the ATV module of MSC. ADAMS, the dynamic simulation of recoil response of tank gun is analyzed.How the recoil force affects the bodywork and the suspension during gun firing, as well as the changing status of the gun muzzle's velocity are gained. All results and analyzing methods are offered for the designing basis of optimizing tank vehicle-gun match. The constructive exploration is beneficial to improving the general capability of tank.

  18. Simulations of Gaussian electron guns for RHIC electron lens

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-02-28

    Simulations of two versions of the electron gun for RHIC electron lens are presented. The electron guns have to generate an electron beam with Gaussian radial profile of the electron beam density. To achieve the Gaussian electron emission profile on the cathode we used a combination of the gun electrodes and shaping of the cathode surface. Dependence of electron gun performance parameters on the geometry of electrodes and the margins for electrodes positioning are presented.

  19. Simulations of Gaussian electron guns for RHIC electron lens

    International Nuclear Information System (INIS)

    Simulations of two versions of the electron gun for RHIC electron lens are presented. The electron guns have to generate an electron beam with Gaussian radial profile of the electron beam density. To achieve the Gaussian electron emission profile on the cathode we used a combination of the gun electrodes and shaping of the cathode surface. Dependence of electron gun performance parameters on the geometry of electrodes and the margins for electrodes positioning are presented.

  20. Acute Alcohol Consumption, Alcohol Outlets, and Gun Suicide

    OpenAIRE

    Branas, Charles C; Richmond, Therese S.; Ten Have, Thomas R.; Wiebe, Douglas J.

    2011-01-01

    A case–control study of 149 intentionally self-inflicted gun injury cases (including completed gun suicides) and 302 population-based controls was conducted from 2003 to 2006 in a major US city. Two focal independent variables, acute alcohol consumption and alcohol outlet availability, were measured. Conditional logistic regression was adjusted for confounding variables. Gun suicide risk to individuals in areas of high alcohol outlet availability was less than the gun suicide risk they incurr...

  1. Total hip arthroplasty in patients with avascular necrosis of the hip. Follow-up observations on cementless and cemented operations.

    Science.gov (United States)

    Katz, R L; Bourne, R B; Rorabeck, C H; McGee, H

    1992-08-01

    Thirty-one patients with avascular necrosis of the hip were treated by 34 total hip arthroplasties (THAs). All patients were observed prospectively with a minimum two-year follow-up evaluation (average, 46 months; range, 24-84 months). Twenty had cemented arthroplasties using contemporary cementing techniques. This included insertion of a medullary plug, cleansing of the canal with a medullary brush, pulsatile lavage irrigation, and insertion of the cement with a cement gun. In 14 hips, a cementless prosthesis was used. Patients were rated using a modified Harris hip score. Sequential postoperative roentgenograms were analyzed in each patient. The overall Harris hip score ratings were 88 in the cemented and 84 in the noncemented groups. Mechanical failure with loosening of the femoral component occurred in one patient who developed deep sepsis. Significant thigh pain occurred in four patients in the noncemented group. Previous studies in the literature have generally reported unfavorable results in patients with avascular necrosis of the hip treated with THA. Using cementless and cemented fixation with contemporary cementing techniques, improved results can be expected. A high incidence of thigh pain (29%) in the cementless group remains a problem. PMID:1499201

  2. Cellulose Acetate Binder-Based LOVA Gun Propellant for Tank Guns.

    Directory of Open Access Journals (Sweden)

    A.G.S. Pillai

    1999-04-01

    Full Text Available Cellulose acetate (CA binder-based low vulnerability ammunition (LOYA gun propellant formulations with varying percentages of fine RDX as energetic ingredient have been studied. RDX percentage varied from 76 to 80 in these formulations. An optimised composition with 78 per cent RDX was then studied exhaustively. Ballistic data determined by closed vessel (CV evaluation and vulnerability aspects obtained by safety tests were then compared vis-a-vis the properties of standard triple base NQ composition. Theoretical prediction and CV test results indicated that the CA binder-based LOVA gun propellant Could satisfactorily meet the ballistic requirements for gun application.

  3. Triaxial shear behavior of a cement-treated sand–gravel mixture

    Directory of Open Access Journals (Sweden)

    Younes Amini

    2014-10-01

    Full Text Available A number of parameters, e.g. cement content, cement type, relative density, and grain size distribution, can influence the mechanical behaviors of cemented soils. In the present study, a series of conventional triaxial compression tests were conducted on a cemented poorly graded sand–gravel mixture containing 30% gravel and 70% sand in both consolidated drained and undrained conditions. Portland cement used as the cementing agent was added to the soil at 0%, 1%, 2%, and 3% (dry weight of sand–gravel mixture. Samples were prepared at 70% relative density and tested at confining pressures of 50 kPa, 100 kPa, and 150 kPa. Comparison of the results with other studies on well graded gravely sands indicated more dilation or negative pore pressure in poorly graded samples. Undrained failure envelopes determined using zero Skempton's pore pressure coefficient (A¯=0 criterion were consistent with the drained ones. Energy absorption potential was higher in drained condition than undrained condition, suggesting that more energy was required to induce deformation in cemented soil under drained state. Energy absorption increased with increase in cement content under both drained and undrained conditions.

  4. OCULAR INJURIES CAUSED BY BB GUN

    Directory of Open Access Journals (Sweden)

    M.S. Farahvash

    1999-08-01

    Full Text Available in ordere to determine the prognosis of perforating eye injuries caused hy BB guns in our patients, the"nvisual and anatomic results of 14 patients with gun injuries seen between September 1996 and February 1998 in Farafti Hospital and private office in Tehran were reviewed. Five patients liad nonn erf orating eye injuries. All perforated eyes underwent scleral buckling, tenseclomy, vitrectomy ami silicone injection. All injured iyes had a visual acuity of light perception or better at presentation. Among 9 cases of perforating injuries. 7 had doable and 2 had single perforation. All patients had a final.

  5. Guns N’ Arenas黑枪事件

    Institute of Scientific and Technical Information of China (English)

    狄艾

    2010-01-01

    奇才队"零号探员"阿里纳斯(Gilbert Arenas)和知名摇滚乐团"枪和玫瑰(Guns N’Roses)"同样发迹于美国加州,但当"枪和阿里纳斯(Guns N’Are nas)"连结在一起时,代志就大条了!先前名气直逼摇滚巨星的阿里纳斯,恐怕将因去年12月的"黑枪事件"身败名裂!

  6. Electron trapping mechanisms in magnetron injection guns

    Science.gov (United States)

    Pagonakis, Ioannis Gr.; Piosczyk, Bernhard; Zhang, Jianhua; Illy, Stefan; Rzesnicki, Tomasz; Hogge, Jean-Philippe; Avramidis, Konstantinos; Gantenbein, Gerd; Thumm, Manfred; Jelonnek, John

    2016-02-01

    A key parameter for the gyrotron operation and efficiency is the presence of trapped electrons. Two electron trapping mechanisms can take place in gyrotrons: (i) the adiabatic trap and (ii) the magnetic potential well. Their influence on the gyrotron operation is analyzed. Two gun design criteria are then proposed to suppress both mechanisms in order to minimize the risk of possible problems. Experimental results of three high power gyrotrons are presented and their performance is correlated to the presence of populations of trapped electrons. Finally, some very general gun design principles are presented for the limitation of harmful electron trapping.

  7. Investigation of pellet acceleration by an arc heated gas gun

    International Nuclear Information System (INIS)

    This report describes work on pellet acceleration by means of an arc heated gas gun. The work is a continuation of the work described in RISO-M-2536. The aim of the work is to obtain velocities well above 2 km/s for 3.2 mm diameter deuterium pellets. By means of a cryogenic arc chamber in which the hydrogen propellant is pre-condensed, extruded deutetrium pellets are accelerated up to a maximum velocity of 1.93 km/s. When increasing the energy input to the arc in order to increase the pellet velocity further the heat input to the extrusion/punching pellet loading mechanism was found to be critical: preparation of pellets became difficult and cooling times between shots became inconveniently long. In order to circumvent this problems the concept of a room temperature hydrogen propellant pellet fed arc chamber was proposed. Preliminary results from acceleration of polyurethane pellets with this arc chamber are described as well as the work of developing of feed pellet guns for this chamber. Finally the report describes design consideration for a high pressure propellant pellet fed arc chamber together with preliminary results obtained with a proto-type arc chamber. (author)

  8. Study of Control Grid Thermionic Cathode RF Gun

    CERN Document Server

    Xiao, Jin; Ming, Li; Xinfan, Yang; Xumin, Shen; Yanan, Chen; Zhou, Xu

    2004-01-01

    In this paper, the beam loading effect of RF Gun was analyzed. To minimize the energy spread, the grid control RF Gun was introduced. The result shows that the grid congrol RF Gun can increase electron beam within 1% energy spread.

  9. 78 FR 11902 - Review of Gun Safety Technologies

    Science.gov (United States)

    2013-02-20

    ... of Justice Programs Review of Gun Safety Technologies AGENCY: National Institute of Justice, JPO, DOJ. ACTION: Notice. SUMMARY: Following the President's Plan to reduce gun violence released on January 16...) is conducting a review of existing and emerging gun safety technologies and plans to issue a...

  10. Should Gun Safety Be Taught in Schools? Perspectives of Teachers

    Science.gov (United States)

    Obeng, Cecilia

    2010-01-01

    Background: Gun-related injuries and deaths among children occur at disproportionately high rates in the United States. Children who live in homes with guns are the most likely victims. This study describes teachers' views on whether gun safety should be taught to children in the preschool and elementary years. Methods: A total of 150 survey…

  11. Gun Violence and Children: Factors Related To Exposure and Trauma.

    Science.gov (United States)

    Slovak, Karen

    2002-01-01

    Study investigated relationship between access to firearms and parental monitoring on rural youths' exposure to gun violence, and examined the effect of gun violence exposure on mental health. Results indicated a substantial number were exposed to gun violence. Exposure was related to firearm access and parental monitoring. Implications for social…

  12. Economic Analysis of a Traveling Gun for Feedyard Dust Suppression

    OpenAIRE

    Amosson, Stephen H.; Bretz, Fran E.; New, Leon L.; Almas, Lal K.

    2007-01-01

    Dust created in feedyards can adversely affect cattle performance. Dust suppression can be accomplished by moistening pen surfaces with traveling gun(s) sprinklers, solid-set sprinklers, and water trucks. This study specifically addresses the fixed and operational costs associated with a traveling gun sprinkler system for various sized feedyards.

  13. Klystron - Space-charge limited flow, guns, Perveance

    International Nuclear Information System (INIS)

    This paper treats Thermionic emission, Cathode as an e- emitter, Space-charge limited effect and 3/2 power law, Perveance, Beam spread due to space charge, Pierce guns, Magnetically immersed guns, Method of gun design including simulations, and Examples, mainly treating E3786, which attendees will operate above 1 MW-CW in a practical exercise course at KEK. (author). 74 refs

  14. Respiratory Health among Cement Workers in Ethiopia

    OpenAIRE

    Zeleke, Zeyede K.

    2011-01-01

    Background: Little is known on dust exposure and respiratory health among cement cleaners. There are only a few follow-up studies on respiratory health among cement factory workers and also studies on acute effects of cement dust exposure are limited in numbers. Objective: This study aimed at assessing cement dust exposure and adverse respiratory health effects among Ethiopian cement production workers, with particular focus on cement cleaners. Method: The first paper was...

  15. Diamond-like Carbon Thin Films Deposited on Ti6Al4V Alloy Surface by Plasma Gun at Atmospheric Pressure%钛合金表面大气压等离子体枪制备类金刚石薄膜

    Institute of Scientific and Technical Information of China (English)

    陈飞; 周海; 张跃飞; 吕反修

    2012-01-01

    在大气下,采用大气压介质阻挡放电(DBD)等离子体枪在低温下<350℃),以甲烷为单体,氩气为工作气体,在Ti6Al4V钛合金表面制备一层类金刚石薄膜(DLC),以期改善钛合金表面摩擦学性能.利用激光拉曼(Raman)光谱和X射线光电子能谱(XPS)分析了所制备DLC薄膜的结构;利用扫描电子显微镜(SEM)观察DLC薄膜的表面形貌;利用划痕仪测量了DLC薄膜与基体的结合力;利用球-盘摩擦磨损实验仪对DLC薄膜的耐磨性能进行了研究.结果表明:在本实验工艺条件下沉积的类金刚石薄膜厚度约为1.0 μm,薄膜均匀且致密,表面粗糙度Ra为13.23 nm.类金刚石薄膜与基体结合力的临界载荷达到31.0N.DLC薄膜具有优良的减摩性,Ti6Al4V表面沉积DLC薄膜后摩擦系数为0.15,较Ti6Al4V基体的摩擦系数0.50明显减小,耐磨性能得到提高.%At atmospheric pressure, diamond-like carbon (DLC) thin films were deposited on the T16A14V alloy surface by a DBD plasma gun at low temperature (<350℃), with CH4 as a precursor and Ar as dilution gas. The structure of the DLC thin film was analyzed by Laser Raman spectroscope and X-ray photoelectron spectroscopy. The surface morphology was observed through scanning electron microscopy. The adhesion between the DLC thin film and the substrate was investigated with the scribe testing. The friction and wear behavior of the DLC thin films under dry sliding against GCrlS steel was evaluated on a ball-on-disc test rig. The results show that it is feasible to prepare a DLC thin film of 1.0 um thickness by a plasma gun. The film is uniform and dense and the surface roughness R. Is about 13.23 nm. The critical load of adhesion force between the DLC thin film and the substrate is 31.0 N. It has been found that the DLC thin film has excellent friction- and wear-resistant behavior. The friction coefficient of the Ti6A14V substrate is about 0.50 under dry sliding against steel, while the DLC thin

  16. Thermal Shock-resistant Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved

  17. Dynamic response of single crystalline copper subjected to quasi-isentropic laser and gas-gun driven loading

    Science.gov (United States)

    Meyers, M.; Jarmakani, H.; McNaney, J. M.; Schneider, M.; Nguyen, J. H.; Kad, B.

    2006-08-01

    Single crystalline copper was subjected to quasi-isentropic compression via gas-gun and laser loading at pressures between 18 GPa and 59 GPa. The deformation substructure was analyzed via transmission electron microscopy (TEM). Twins and laths were evident at the highest pressures, and stacking faults and dislocation cells in the intermediate and lowest pressures, respectively. The Preston-Tonks-Wallace (PTW) constitutive description was used to model the slip-twinning process in both cases.

  18. Development of Bulk Nanocrystalline Cemented Tungsten Carbide for Industrial Applicaitons

    Energy Technology Data Exchange (ETDEWEB)

    Z. Zak Fang, H. Y. Sohn

    2009-03-10

    This report contains detailed information of the research program entitled "Development of Bulk Nanocrystalline Cemented Tungsten Carbide Materials for Industrial Applications". The report include the processes that were developed for producing nanosized WC/Co composite powders, and an ultrahigh pressure rapid hot consolidation process for sintering of nanosized powders. The mechanical properties of consolidated materials using the nanosized powders are also reported.

  19. Pulsed electron gun and linear accelerator fitted with such a gun

    International Nuclear Information System (INIS)

    This invention relates to a pulsed electron gun comprising a leak-tight insulating tube closed at one end. A voltage of several tens of kilovolts is applied by cables to the ends of the tube. Among its other features this gun includes a conducting tube fitted inside an insulating tube on the same centre line, in a leak-tight manner to it. This conducting tube forms the grid support, and the bottom of the well so formed being closed by a conducting plate insulated from the conducting tube by an insulating ring, this plate becomes the support of the gun cathode. The grid support is part of the vacuum containment so formed. The electron linear accelerator comprising such a pulsed electron gun is also described

  20. Health hazards of cement dust

    International Nuclear Information System (INIS)

    ven in the 21st century, millions of people are working daily in a dusty environment. They are exposed to different types of health hazards such as fume, gases and dust, which are risk factors in developing occupational disease. Cement industry is involved in the development of structure of this advanced and modern world but generates dust during its production. Cement dust causes lung function impairment, chronic obstructive lung disease, restrictive lung disease, pneumoconiosis and carcinoma of the lungs, stomach and colon. Other studies have shown that cement dust may enter into the systemic circulation and thereby reach the essentially all the organs of body and affects the different tissues including heart, liver, spleen, bone, muscles and hairs and ultimately affecting their micro-structure and physiological performance. Most of the studies have been previously attempted to evaluate the effects of cement dust exposure on the basis of spirometry or radiology, or both. However, collective effort describing the general effects of cement dust on different organ and systems in humans or animals, or both has not been published. Therefore, the aim of this review is to gather the potential toxic effects of cement dust and to minimize the health risks in cement mill workers by providing them with information regarding the hazards of cement dust. (author)

  1. Gun Possession among American Youth: A Discovery-Based Approach to Understand Gun Violence

    OpenAIRE

    Kelly V Ruggles; Sonali Rajan

    2014-01-01

    OBJECTIVE: To apply discovery-based computational methods to nationally representative data from the Centers for Disease Control and Preventions' Youth Risk Behavior Surveillance System to better understand and visualize the behavioral factors associated with gun possession among adolescent youth. RESULTS: Our study uncovered the multidimensional nature of gun possession across nearly five million unique data points over a ten year period (2001-2011). Specifically, we automated odds ratio cal...

  2. Gun Possession among American Youth: A Discovery-Based Approach to Understand Gun Violence

    OpenAIRE

    Ruggles, Kelly V.; Rajan, Sonali

    2014-01-01

    Objective To apply discovery-based computational methods to nationally representative data from the Centers for Disease Control and Preventions’ Youth Risk Behavior Surveillance System to better understand and visualize the behavioral factors associated with gun possession among adolescent youth. Results Our study uncovered the multidimensional nature of gun possession across nearly five million unique data points over a ten year period (2001–2011). Specifically, we automated odds ratio calcu...

  3. Effective launch package integration for electromagnetic guns

    Energy Technology Data Exchange (ETDEWEB)

    Hayden, T.E. [Kaman Sciences Corp., Colorado Springs, CO (United States); Dethlefsen, R. [Maxwell Labs., Inc., San Diego, CA (United States); Price, J.H. [Univ. of Texas, Austin, TX (United States). Center for Electromechanics

    1995-01-01

    Many engineering disciplines must be considered when designing launch packages for electromagnetic guns. These include electromechanics, plasma physics, fluid dynamics, structures, materials science, aerodynamics, thermodynamics, flight dynamics, and terminal effects. Often, the requirements of one discipline will be in direct conflict with the requirements of another. Each discipline can claim to be of overriding importance, but all aspects of launch package design must be considered if the gun system is to succeed in its mission. Choices must be made regarding launch package configuration. Base-pushing or mid-riding solutions are possible with solid, hybrid or plasma armatures. Fully optimized launch package designs must be used in comparisons to find the actual optimal design point. The most effective design for one gun system will not necessarily be the most effective for another. This paper discusses the interplay among the various engineering disciplines involved in launch package design. Successful testing of integrated projectile/armature/sabot configurations from 90 mm EM guns is reviewed.

  4. How Sociology Texts Address Gun Control

    Science.gov (United States)

    Tonso, William R.

    2004-01-01

    William R. Tonso has chosen an issue that he knows something about to examine how sociology textbooks address controversy. Appealing for gun control is fashionable, but it is at odds with a fondness that ordinary Americans have for their firearms--one that is supported by a growing body of research on deterrence to crime. There are two sides to…

  5. College Students Opinions on Gun Violence.

    Science.gov (United States)

    Lewis, Rhonda K; LoCurto, Jamie; Brown, Kyrah; Stowell, David; Maryman, J'Vonnah; Dean, Amber; McNair, Thoi; Ojeda, Debbie; Siwierka, Julia

    2016-06-01

    Gun violence and control issues have become serious public health problems. This study gathered the opinions from 419 college students from a Midwestern University. Participants were asked about beliefs about purchasing assault weapons, beliefs about bringing handguns to college campuses and beliefs about contributing factors that lead to gun violence. Participants completed surveys online. The findings showed that overall 54 % of respondents believed that military assault weapons should be banned and 53 % agree that teachers should be allowed to carry a registered handgun on campus. There were statistically significant differences between males and females on these issues. For instance, females believed military assault weapons and high capacity magazines should be banned more than 1.9 times (p = .004) p gun violence were decline in parenting and family values (17 %), gang involvement (14 %), bullying (13.8 %) and guns being easy to obtain (13.8 %). Limitations and implications for policy work are discussed. PMID:26516018

  6. Nerf Guns Strike a Nerve on Campuses

    Science.gov (United States)

    Young, Jeffrey R.

    2008-01-01

    Killing zombies on campus just isn't as much fun as it used to be. Students at Bowling Green State University once carried Nerf guns for a week each semester, shooting the zombies before the creatures could tag them. Participants were seen by most bystanders as nerdy but harmless kids who liked role-playing. These days, bright plastic Nerf guns…

  7. Guns on Campus: A Chilling Effect

    Science.gov (United States)

    Mash, Kenneth M.

    2013-01-01

    The author of this article observes that, while much has been written on the overall topic of safety with regard to allowing guns on college campuses, little has been said about how allowing the possession of deadly weapons can create a "chilling effect" on academic discussions. This article considers how some universities have…

  8. Reconnection conditions for a coaxial plasma gun

    International Nuclear Information System (INIS)

    A fluid model for the flow conditions necessary to form a compact torus from the plasma ejected by a coaxial plasma gun is developed. This is done by finding the conditions for which the steady-flow equations break down. Results are found for two cases; variable external flux and variable outer-wall radius

  9. Magnetic guns with cylindrical permanent magnets

    DEFF Research Database (Denmark)

    Vokoun, David; Beleggia, Marco; Heller, Luděk

    2012-01-01

    The motion of a cylindrical permanent magnet (projectile) inside a tubular permanent magnet, with both magnets magnetized axially, illustrates nicely the physical principles behind the operation of magnetic guns. The force acting upon the projectile is expressed semi-analytically as derivative of...... the generated forces and motion of the inner cylindrical magnet....

  10. Green plasticizers for multibase gun propellants (Lecture)

    NARCIS (Netherlands)

    Schoolderman, C.; Driel, C.A. van; Zebregs, M.

    2007-01-01

    TNO Defence, Security and Safety has a long history of research on gun propellants. Areas investigated are formulating (new ingredients, optimization), manufacturing, charge design and lifetime assessment [1,2,3,4,5]. In conventional propellants inert plasticizers are used to alter performance, proc

  11. Safety Plan for Schools: No Guns

    Science.gov (United States)

    Shah, Nirvi

    2013-01-01

    In a pre-emptive move against a school safety proposal from the National Rifle Association that is expected to include a call for more people trained and approved to carry guns at schools, a coalition of civil rights and education groups unveiled its own safety plan last week. It seeks the creation of positive school climates, thoughtful and…

  12. Simulation of an rf thermionic gun

    Science.gov (United States)

    Liu, Hongxiu

    1991-07-01

    An rf thermionic gun is simulated using Superfish and Parmela. A strong front-end compression for the bunch is demonstrated. The energy spread, phase spread and emittance of a single electron micropulse are examined subtly by cutting the bunch into slices corresponding to different initial emission phases of the particles.

  13. Youth Suicide and Guns. Firearm Facts.

    Science.gov (United States)

    Duker, Laurie, Ed.

    Whether or not a suicide attempt results in death depends in large part on the method chosen. If a teenager attempts suicide with a gun, his or her death is nearly guaranteed. This brief fact sheet presents data on firearms and suicide, the third leading cause of death for adolescents and young adults in the United States. Any number of societal…

  14. Capital Punishment, Gun Ownership, and Homicide.

    Science.gov (United States)

    Kleck, Gary

    1979-01-01

    Examines two controversial questions related to the problem of interpersonal violence in America: (1) Does use of the death penalty exert any measurable influence on the rate of homicide in the United States? (2) What relationship, if any, exists between the level of gun ownership and the level of homicide violence? (Author)

  15. The important relationship between socioeconomic decline, masculinity, and guns

    OpenAIRE

    Carlson, Jennifer

    2015-01-01

    Recent events have reopened the debate over the role of guns in U.S. society, at a time when many states are expanding gun laws through open and concealed carry measures. How can we account for the popularity of guns in America, especially among men? Jennifer Carlson investigated this question by interviewing, and spending time with, gun-owning men in Michigan. She found that for these men, protecting their family and community was an important part of their gun ownership, a role which is has...

  16. Child Access Prevention Laws, Youth Gun Carrying, and School Shootings

    OpenAIRE

    Anderson, D. Mark; SABIA, JOSEPH J.

    2016-01-01

    Despite intense public interest in keeping guns out of schools, next to nothing is known about the effects of gun control policies on youth gun carrying or school violence. Using data from the Youth Risk Behavior Surveys (YRBS) for the period 1993-2013, this study is the first to examine the relationship between child access prevention (CAP) gun controls laws and gun carrying among high school students. Our results suggest that CAP laws are associated with a 13 percent decrease in the rate of...

  17. Development of the electron gun control system of SSRF

    International Nuclear Information System (INIS)

    An electron gun is the key part of a linac, the beam quality of which depends on beam quality of the electron gun, hence the need of a stable control system of the electron gun to ensure its safe operation.In this paper, we report our progresses in developing the linac's electron gun control system of Shanghai Synchrotron Radiation Facility (SSRF). It uses PLC as the device controllers, with the monitoring software developed on EPICS. The whole system is connected by Ethernet. The PLC and Ethernet technology ensures good reliability and easy maintenance of the electron gun control system. (authors)

  18. Fired Models of Air-gun Source and Its Application

    Institute of Scientific and Technical Information of China (English)

    Luo Guichun; Ge Hongkui; Wang Baoshan; Hu Ping; Mu Hongwang; Chen Yong

    2008-01-01

    Air-gun is an important active seismic source. With the development of the theory about air-gun array, the technique for air-gun array design becomes mature and is widely used in petroleum exploration and geophysics. In order to adapt it to different research domains,different combination and fired models are needed. At the present time, there are two firedmodels of air-gun source, namely, reinforced initial pulse and reinforced first bubble pulse.The fired time, space between single guns, frequency and resolution of the two models are different. This comparison can supply the basis for its extensive application.

  19. Elusive Facts About Gun Violence: Where Good Surveys Go Bad

    OpenAIRE

    Cook, Philip J.; Jens Ludwig

    2014-01-01

    The evidence base for the study of guns and violence begins with data on such fundamental issues as the number and distribution of guns, the number of people shot each year in criminal assaults, and the frequency of gun use in self-defense. It seems that these simple descriptive statistics should be readily available, and in fact the rhetoric of the debate over gun control in the United States routinely includes reference to 300 million guns, or 100,000 people who are shot each year, or 2.5 m...

  20. Acute alcohol consumption, alcohol outlets, and gun suicide.

    Science.gov (United States)

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

    2011-01-01

    A case-control study of 149 intentionally self-inflicted gun injury cases (including completed gun suicides) and 302 population-based controls was conducted from 2003 to 2006 in a major US city. Two focal independent variables, acute alcohol consumption and alcohol outlet availability, were measured. Conditional logistic regression was adjusted for confounding variables. Gun suicide risk to individuals in areas of high alcohol outlet availability was less than the gun suicide risk they incurred from acute alcohol consumption, especially to excess. This corroborates prior work but also uncovers new information about the relationships between acute alcohol consumption, alcohol outlets, and gun suicide. Study limitations and implications are discussed. PMID:21929327

  1. Improved DC Gun Insulator Assembly

    Energy Technology Data Exchange (ETDEWEB)

    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

  2. Ways to Increase Launch Velocities of 2-Stage Gas Guns

    Science.gov (United States)

    Bogdanoff, David W.; Cambier, Jean-Luc; Arnold, James O. (Technical Monitor)

    1994-01-01

    The amount of space debris is rapidly increasing and the debris is distributed over a wide variety of orbits. Satellites, manned space vehicles and space stations will have to pay increasing attention to the dangers of impacts with space debris. Various armoring techniques (i.e., double or triple layer armor) will have to tested extensively to determine the most effective armor per unit weight. Intersecting near-earth orbits can lead to impact velocities up to 15 km/sec. Conventional two-stage light gas guns can launch intact, controlled-shape projectiles with a density of 1.2 gm/cc and length- to-diameter ratios of 0.5-1.0 at velocities up to 8-9 km/sec. Higher velocities (10-11 km/sec) can be obtained' for very light projectiles. The higher launch velocities tend to be very severe on the high pressure coupling and barrel of the gun and lead to short component lifetimes. Clearly, the ability to raise the launch velocity of a gun (for reasonably massive projectile shapes) from 8-9 km/sec to 11-13 km/sec (or higher), without reduction of component lifetimes, would have significant benefits. This would allow much better simulation of the higher velocity debris impacts as well as better simulation of high speed re-entry into planetary atmospheres. Several techniques for increasing the launcher muzzle velocity above 8-9 km/sec have been studied using CFD simulations and appear to offer the potential for significant gains. The first technique is to use multiple compressions, instead of a single compression, in the pump tube of the light gas gun. In a sense, this is a kind of pre-heating of the gas in the pump tube; other types of pre-heating have yielded disappointing results in the past. The dynamics of the multiple compression pump tube is very different, however, from the earlier techniques, where the pump tube was typically heated ohmically before the gun 2 cycle was started. In this paper, we present CFD calculations that show that significant increases in muzzle

  3. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    A K Misra; Renu Mathur

    2007-06-01

    The scope of magnesium oxychloride (MOC) cement in concrete works has been evaluated. MOC cement concrete compositions of varying strengths having good placing and finishing characteristics were prepared and investigated for their compressive and flexural strengths, -values, abrasion resistance etc. The durability of MOC concrete compositions against extreme environmental conditions viz. heating–cooling, freezing–thawing, wetting–drying and penetration and deposition of salts etc were investigated. The results reveal that MOC concrete has high compressive strength associated with high flexural strength and the ratio of compressive to flexural strength varies between 6 and 8. The elastic moduli of the compositions studied are found to be 23–85 GPa and the abrasion losses between 0.11 and 0.20%. While alternate heating–cooling cycles have no adverse effect on MOC concrete, it can be made durable against freezing–thawing and the excessive exposure to water and salt attack by replacing 10% magnesium chloride solution by magnesium sulphate solution of the same concentration.

  4. Investigation of pellet acceleration by an arc heated gas gun

    International Nuclear Information System (INIS)

    This report describes work on pellet acceleration by means of an arc heated gas gun. Preliminary results were described in Riso-M-2536 and in Riso-M-2650. This final report describes the work carried out from 1987.03.31 to 1988.09.30. An arc heated hydrogen gas source, for pneumatic acceleration of deuterium pellets to velocities above 2 km/s, was developed. Experiments were performed with an arc chamber to which different methods of hydrogen supply were possible, and to which the input of electrical power could be programmed. Results in terms of pressure transients and acceleration curves are presented. Maximum pellet velocities approaching 2 km/s were obtained. This limit is discussed in relation to the presented data. Finally this report contains a summary and a conclusion for the entire project. (author) 34 ills., 3 refs

  5. Ballistic evaluationof LOVA propellant in high calibre gun

    Directory of Open Access Journals (Sweden)

    A.G.S. Pillai

    2001-04-01

    Full Text Available 'This paper presents the data obrained on dynamic firing of a cellulose acetate binder-based low vulnerability ammunition (LOV A propellant using 120 mm fin-stabilised armour piercing discarding sabot (FSAPDS kinetic energyammunition. An optimised propellant composition formulated ~sing fine RDX as an energetic ingredient and a mixture of cellulose acetate and nitrocellulose as binder was qualified fit for firing in a high calibre gun by its successful static evaluation for absolute ballistics using high pressure closed vessel technique. Dynamic firing of the propellant processed in heptatubular geometry was undertaken to assess the propellant charge mass. This propellant achieved higher muzzle velocity as compared to the standard NQ/M119 triple-base propellant while meeting the non-vulnerability characteristics convincingly.

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

    Science.gov (United States)

    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

  7. Elastoplastic cup model for cement-based materials

    Directory of Open Access Journals (Sweden)

    Yan ZHANG

    2010-03-01

    Full Text Available Based on experimental data obtained from triaxial tests and a hydrostatic test, a cup model was formulated. Two plastic mechanisms, respectively a deviatoric shearing and a pore collapse, are taken into account. This model also considers the influence of confining pressure. In this paper, the calibration of the model is detailed and numerical simulations of the main mechanical behavior of cement paste over a large range of stress are described, showing good agreement with experimental results. The case study shows that this cup model has extensive applicability for cement-based materials and other quasi-brittle and high-porosity materials in a complex stress state.

  8. Thermodynamic and structural characteristics of cement minerals at elevated temperature

    International Nuclear Information System (INIS)

    We have instituted an experimental and including program designed to elucidate the structural and thermodynamic response of cement minerals to elevated temperature. Components of the program involve: (a) synthesis of hydrated Ca-silicates; (b) structural analysis of cement phases induced by heating and dehydration/rehydration; (c) mechanistic and thermodynamic descriptions of the hydration/dehydration behavior of hydrated Ca-silicates as a function of temperature, pressure and relative humidity; (d) study of naturally occurring hydrated Ca-silicates; and (e) measurements of thermodynamic data for hydrated Ca-silicates

  9. Advanced Concepts of the Propulsion System for the Futuristic Gun Ammunition

    OpenAIRE

    R.S. Darnse; Amarjit Singh

    2003-01-01

    This review paper reports various concepts of the gun propulsion system to meet the goal of the futuristic hypervelocity projectiles. The nonconventional concepts, such as liquid gun propellant, rail gun, coil gun, electrothermal gun, electrothermal chemical gun along with conventional energetic solid gun propellant have been discussed. Even though muzzle velocity around 2000 m/s has been claimed to be achieved using such nonconventional propulsion systems, it will take quite some time before...

  10. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: HVLP COATING EQUIPMENT, ITW AUTOMOTIVE REFINISHING, DEVILBISS GTI-600G, HVLP SPRAY GUN

    Science.gov (United States)

    This report presents the results of the verification test of the DeVilbiss GTi-600G high-volume, low-pressure gravity-feed spray gun, hereafter referred to as the DeVilbiss GTi, which is designed for use in automotive refinishing. The test coating chosen by ITW Automotive Refinis...

  11. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: HVLP COATING EQUIPMENT, ITW AUTOMOTIVE REFINISHING, DEVILBISS FLG-631-318 HVLP SPRAY GUN

    Science.gov (United States)

    This report presents the results of the verification test of the DeVilbiss FLG-631-318 high-volume, low-pressure gravity-feed spray gun, hereafter referred to as the DeVilbiss FLG, which is designed for use in automotive refinishing. The test coating chosen by ITW Automotive Refi...

  12. Intraoperative monitoring for safety of total hip arthroplasty using third-generation cementing technique

    Institute of Scientific and Technical Information of China (English)

    LI Zi-jian; ZHANG Ke; YANG Hong; LIU Yan; L(U) Jing-qiao

    2009-01-01

    Background Controversies on the safety of the cement application between cemented and uncemented total hip arthroplasty (THA) have been existing for decades. The purpose of this study was to observe the changes in mean arterial pressure (MAP), heart rate (HR) and oxygen pressure (PaO2) during cemented THA, and to evaluate the intraoperative safety of using the third-generation cementing technique and investigate whether the intraoperative risk is higher in acute femoral neck fracture patients than non-traumatic patients. Methods Forty-two patients who underwent cemented THA between November 2005 and September 2007 were prospectively included in this study. The third-generation cementing technique as vacuum mixing and pulsatile lavage was used strictly. The MAP and HR were monitored and documented during each operation. Blood gas analysis was performed at exposure, cup implantation, stem implantation and wound closure. MAP, HR and PaO2 were compared between pre- and post-cement application. Comparisons of MAP, HR and PaO2 between patients with acute femoral neck fracture and non-traumatic patiens were performed as well. Results No intraoperative cardiopulmonary complication occurred in these cases. No obvious changes were observed in MAP, HR and PaO2 after cement application. There was no significant difference in MAP, HR and PaO2 between acute femoral fracture patients (18 patients) and non-traumatic patients (24 patients).Conclusions The results of this study suggested that the invasive blood pressure monitoring and blood gas analysis are essential for patients undergoing cemented THA, especially for patients with femoral neck fracture. The third-generation cementing technique is safe to use in THA.

  13. Fast Plasma from a Coaxial Gun

    International Nuclear Information System (INIS)

    The coaxial gun in use here is a source or two different plasmas produced by separate mechanisms. Abundant slow (∼107 cm/sec) deuterium plasma is produced directly by the j x B interaction of the radial plasma current and the magnetic field of the feed current along the centre electrode. The current disturbance moves through the injected gas toward the gun muzzle at ∼2.5 x 107 cm/sec, storing energy behind it in magnetic field and plasma motion. The gun, with its stored energy, functions as a high power low impedance electrical generator to drive into the vacuum beyond the gun muzzle a jet of current which is the source of the fast plasma (∼5 x 1017 deuterons, ∼108 cm/sec). The current jet and the plasma it produces are the subjects of these experiments. The mechanism of acceleration is complicated and imperfectly understood, but considerable insight has been gained by an extensive series of experiments, using as diagnostics the following: external diamagnetic pickup loops, intra vacuo Rogowsky loops, electric probes, external capacitive pickup electrodes, magnetic and electrostatic particle deflection analysis, spectroscopy, target light photography, time of flight with and without a guide field, d-d neutrons from the plasma volume and other methods. The picture which emerges is one of a complicated magneto-electric process taking place in front of the gun muzzle. The acceleration process depends on low gas density there as contrasted'with high density inside the gun. The fast plasma is largely derived from gas adsorbed on the electrodes. This makes necessary a clean vacuum so as to avoid contamination with highly ionized fast impurity ions (C5+, 108 cm/sec). Electrode material evaporates but appears not to be a serious contaminant because it comes late. The high voltage actually accelerating the ions is associated with the rapid expansion into vacuum of a magnetic flux volume around the jet. Fast plasma is emitted in a narrow conical distribution with an

  14. Results of field testing the cement evaluation tool

    Energy Technology Data Exchange (ETDEWEB)

    Leigh, C.A.; Finlayson, C.G.; Van der Kolk, C.

    1984-01-01

    The Cement Evaluation Tool (CET) developed by Schlumberger employs a pulse-echo technique using eight sonic transducers to investigate the casing cement bond. The tool has been widely field tested in a clastic environment in Brunei (N.W. Borneo), across both oil and gas bearing reservoirs. Numerous comparisons of the CET with conventional CBL/VDL logs have been made. Across oil and water bearing intervals the CET is shown to compare favourably with the CBL/VDL and yields significant additional information on channeling, cement distribution, and the success of casing centralization. In addition, the accuracy of the acoustic calipers have proved sufficient to be used in assisting drilling and completion operations. The response of the tool to a microannulus has also been demonstrated by multiple runs under varying wellbore pressures.

  15. Cements in Radioactive Waste Disposal

    International Nuclear Information System (INIS)

    The use of cement and concrete to immobilise radioactive waste is complicated by the wide- ranging nature of inorganic cementing agents available as well as the range of service environments in which cement is used and the different functions expected of cement. For example, Portland cement based concretes are widely used as structural materials for construction of vaults and tunnels. These constructions may experience a long pre-closure performance lifetime during which they are required to protect against collapse and ingress of water: strength and impermeability are key desirable characteristics. On the other hand, cement and concrete may be used to form backfills, ranging in permeability. Permeable formulations allow gas readily to escape, while impermeable barriers retard radionuclide transport and reduce access of ground water to the waste. A key feature of cements is that, while fresh, they pass through a fluid phase and can be formed into any shape desired or used to infiltrate other materials thereby enclosing them into a sealed matrix. Thereafter, setting and hardening is automatic and irreversible. Where concrete is used to form structural elements, it is also natural to use cement in other applications as it minimises potential for materials incompatibility. Thus cement- mainly Portland cement- has been widely used as an encapsulant for storage, transport and as a radiation shield for active wastes. Also, to form and stabilise structures such as vaults and silos. Relative to other potential matrices, cement also has a chemical immobilisation potential, reacting with and binding with many radionuclides. The chemical potential of cements is essentially sacrificial, thus limiting their performance lifetime. However performance may also be required in the civil engineering sense, where strength is important, so many factors, including a geochemical description of service conditions, may require to be assessed in order to predict performance lifetime. The

  16. Cement/slag chemistry studies

    International Nuclear Information System (INIS)

    The performance of cement-based matrices intended for radwaste immobilization is assessed. The long-term performance of the matrix is characterized by thermodynamic evaluation of experimental data. The results are presented in a general form, amenable to a range of specific formulations. The interaction of specific radwaste components with cements has been studied, using Iodine as an example. It occurs as both I- and IO3- species, but these differ sharply in sorption characteristics. The effect of ionizing radiation of the pH and Eh of cement matrices is reported. (author)

  17. Effect of nitrogen flow rate on properties of CrN films Prepared by HCD-gun

    OpenAIRE

    A.J. Novinrooz; H. Seyedi

    2006-01-01

    Purpose: The effect of reactant nitrogen gas flow rate on the tribological properties of CrN thin films was studied.Design/methodology/approach: Hollow Cathode Discharge gun (HCD-gun) was employed for the coating of CrN films on the glass and SS-316 sub strum. The reactant nitrogen with different flow was fed in to the vacuum chamber of 3x10-3 Pa pressure to form Cr N composite under experimental condition.Findings: The crystalline phase and micro structural studies of the specimens were carr...

  18. Field Test Kit for Gun Residue Detection

    Energy Technology Data Exchange (ETDEWEB)

    WALKER, PAMELA K.; RODACY, PHILIP J.

    2002-01-01

    One of the major needs of the law enforcement field is a product that quickly, accurately, and inexpensively identifies whether a person has recently fired a gun--even if the suspect has attempted to wash the traces of gunpowder off. The Field Test Kit for Gunshot Residue Identification based on Sandia National Laboratories technology works with a wide variety of handguns and other weaponry using gunpowder. There are several organic chemicals in small arms propellants such as nitrocellulose, nitroglycerine, dinitrotoluene, and nitrites left behind after the firing of a gun that result from the incomplete combustion of the gunpowder. Sandia has developed a colorimetric shooter identification kit for in situ detection of gunshot residue (GSR) from a suspect. The test kit is the first of its kind and is small, inexpensive, and easily transported by individual law enforcement personnel requiring minimal training for effective use. It will provide immediate information identifying gunshot residue.

  19. High Impetus Cool Burning Gun Propellants

    Directory of Open Access Journals (Sweden)

    R.S. Dames

    2000-07-01

    Full Text Available This study explores the possibility of reducing the flame temperature (Tf without decrease in impetus of RDX-NC matrix-based high energy gun propellants by partial replacement of RDX with triaminoguanidine nitrate (TAGN. Compositions containing TAGN as an energetic oxidiser with varying percentage of RDX have been formulated. Glycidyl azide polymer was incorporated as an energetic plasticiser to achieve the higher level of impetus. Performance in terms of ballistic parameters (theoretical/experimental sensitivity, thermal characteristics, stability and mechanical properties was evaluated and compared with the basic composition containing RDX as a single oxidiser. Experimental data indicates that the partial replacement of RDX by TAGN in gun propellant compositions decreases Tf significantly with only marginal decrease in impetus. "

  20. Femtosecond electron microscopy using photocathode RF gun

    International Nuclear Information System (INIS)

    The revealing and understanding of ultrafast structural-change induced dynamics are essential not only in physics, chemistry and biology, but also are indispensable for the development of new materials, new devices and applications. Both new RF gun based ultrafast relativistic electron diffraction and microscopy (UED and UEM) have being developed in Osaka University to probe directly structural changes at the atomic scale with sub-100 fs temporal resolution in materials. The first prototype of relativistic-energy UEM using a femtosecond photocathode RF gun has been developed. Both ultrafast diffraction and image measurements have been succeeded using a femtosecond electron beam. In this paper, the development of the UEM prototype and the first experiments of relativistic-energy electron imaging will be reported. (author)

  1. Development of L-band RF gun

    International Nuclear Information System (INIS)

    Continuing from the report at the previous annual meeting, we show the present status about the development of the L-band photocathode RF gun which is conducted by the collaborations with the groups of Osaka University, KEK, and Hiroshima University. At the last summary, we carried out the high power test and RF processing of the RF-gun cavity at KEK's Superconducting radiofrequency Test Facility (STF). Comparing with the predecessor working at STF, we find that the RF process of this cavity make faster progress. In this report, we show the result of this high power RF processing of the cavity and the present problems found out after that. We also show the development of the laser system as the cathode driver. (author)

  2. Current diffusion in rail-gun conductors

    International Nuclear Information System (INIS)

    A method has been developed to analyze one- and two-dimensional, nonlinear current diffusion in rail-gun conductors. A nonlinear current-diffusion equation that accounts for the temperature dependence of electrical conductivity has been developed from Maxwell's equations. A finite-difference heat-transfer computer program was adapted to solve the current-diffusion and thermal-diffusion problems for rail-gun conductors in one and two dimensions. The nonlinear current-diffusion equation was also extended to account for the magnetic-field dependence of the magnetic permeability, thus allowing ferromagnetic materials to be considered. A one-dimensional finite-difference technique was developed for ferromagnetic materials. Two one-dimensional test problems that compare results with other analyses are discussed. A series of calculations of current density and rail temperature was done for various size rectangular rails. One analysis of current diffusion in a ferromagnetic material was also performed

  3. Cementing porcelain-fused-to-metal crowns.

    Science.gov (United States)

    Vadachkoria, D

    2009-12-01

    The clinical success of fixed prosthodontic restorations can be complex and involve multifaceted procedures. Preparation design, oral hygiene/micro flora, mechanical forces, and restorative materials are only a few of the factors which contribute to overall success. One key factor to success is choosing the proper cement. Popular use of cements for PFM crowns has shifted from zinc phosphate and glass ionomer cements to resin-reinforced glass ionomer, or RRGI, cements. This change has been rapid and profound. Dental cements have always been less than ideal materials, but this is shift to the relatively new RRGI category justified. Resin-reinforced glass ionomer (RRGI) cements appear to be better than zinc phosphate and glass ionomer cements when placing porcelain-to-metal crowns. RRGI cements, such as RelyX Luting, Fuji Plus and Vitremer Luting Cement, satisfy more of the ideal characteristics of PFM cementation than any other previous cement. Expansion of all three cements has not caused any apparent problems with the cements when used with PFM or metal crowns, but these cements, however, should be avoided when cementing all-ceramic crowns. PMID:20090144

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

    Science.gov (United States)

    2010-10-01

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

  5. Gun Laws and Crime: An Empirical Assessment

    OpenAIRE

    Matti Viren

    2013-01-01

    This paper deals with the effect of gun laws on crime. Several empirical analyses are carried to investigate the relationship between five different crime rates and alternative law variables. The tests are based on cross-section data from US sates. Three different law variables are used in the analysis, together with a set of control variables for income, poverty, unemployment and ethnic background of the population. Empirical analysis does not lend support to the notion that crime laws would...

  6. Statistics tolerances on built up guns.

    Directory of Open Access Journals (Sweden)

    J. P. Sirpal

    1962-07-01

    Full Text Available The strength of built up guns depends on the shrinkages allowed between cylinders and therefore for a given strength, the assembly is either selective or the nominal sizes are so chosen as to give the required shrinkage for a worst combination, it can be seen from the analysis that with little disadvantage tolerances can be greatly increased assuming random assemblies of parts whose sizes follow a normal pattern. This can bring down production costs considerably.

  7. Accurate calculations of thermionic electron gun properties

    Czech Academy of Sciences Publication Activity Database

    Jánský, Pavel; Lencová, Bohumila; Zlámal, J.

    Berlin: Springer, 2008 - (Luysberg, M.; Tillmann, K.; Weirich, T.), s. 557-558 ISBN 978-3-540-85154-7. [EMC 2008 - European Microscopy Congress /14./. Aachen (DE), 01.09.2008-05.09.2008] R&D Projects: GA AV ČR IAA100650805 Institutional research plan: CEZ:AV0Z20650511 Keywords : electron emission * electron gun * space charge Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  8. Magnetic guns with cylindrical permanent magnets

    Czech Academy of Sciences Publication Activity Database

    Vokoun, David; Beleggia, M.; Heller, Luděk

    2012-01-01

    Roč. 324, č. 9 (2012), s. 1715-1719. ISSN 0304-8853 R&D Projects: GA ČR(CZ) GAP107/11/0391; GA AV ČR IAA100100920 Institutional research plan: CEZ:AV0Z10100520 Keywords : permanent magnet * cylindrical magnet * Earnshaw's theorem * magnetic gun * magnetostatic interaction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.826, year: 2012 http://www.sciencedirect.com/science/article/pii/S0304885311008997

  9. Gun Laws and Crime: An Empirical Assessment

    OpenAIRE

    Matti Viren

    2012-01-01

    This paper deals with the effect of gun laws on crime. Several empirical analyses are carried to investigate the relationship between five different crime rates and alternative law variables. The tests are based on cross-section data from US sates. Three different law variables are used in the analysis together with a set of control variables for income, poverty, unemployment and ethnic background of the population. Empirical analysis does not lend support to the notion that crime laws would ...

  10. Cylinder fragmentation using gas gun techniques

    International Nuclear Information System (INIS)

    In this study an experimental technique for study of cylinder fracture fragmentation characteristics has been developed on a two-stage light gas gun. This test method allows the study of cylinder fracture fragmentation in a laboratory environment under well-controlled loading conditions. Application of this technique allows measure of failure strain, strain rates, expansion velocity, and fragmentation toughness. Results of several experiments on Aermet steel are presented

  11. Two-stage plasma gun based on a gas discharge with a self-heating hollow emitter.

    Science.gov (United States)

    Vizir, A V; Tyunkov, A V; Shandrikov, M V; Oks, E M

    2010-02-01

    The paper presents the results of tests of a new compact two-stage bulk gas plasma gun. The plasma gun is based on a nonself-sustained gas discharge with an electron emitter based on a discharge with a self-heating hollow cathode. The operating characteristics of the plasma gun are investigated. The discharge system makes it possible to produce uniform and stable gas plasma in the dc mode with a plasma density up to 3x10(9) cm(-3) at an operating gas pressure in the vacuum chamber of less than 2x10(-2) Pa. The device features high power efficiency, design simplicity, and compactness. PMID:20192469

  12. Patterned imprint mark due to the folded shoulder stock: a possible finding in contact shots from submachine guns.

    Science.gov (United States)

    Grosse Perdekamp, Markus; Braunwarth, Roland; Pollak, Stefan

    2008-06-10

    The muzzle imprint (barrel mark) is a pressure abrasion typically associated with contact shots. Apart from the contours of the actual muzzle profile, other constructional parts such as the front sight and/or the recoil spring guide of semiautomatic pistols may be imprinted next to the bullet entrance wound. In some types of submachine guns the shoulder stock can be folded forward so that its end partly encircles the muzzle. If such a weapon was in contact with the skin at the instant of discharge, a corresponding contusion mark is to be expected. The imprint configuration may point to the type of weapon and to the way in which the gun had been held when firing the shot. The paper presents the injury pattern in a 36-year-old man who committed suicide with a Scorpion SA Vz 61 submachine gun cal. 7.65mm Browning from former Czechoslovakia. PMID:18262741

  13. Sliding wear of cemented carbides

    International Nuclear Information System (INIS)

    Cemented carbides are known to be very hard and wear resistant and are therefor often used in applications involving surface damage and wear. The wear rate of cemented carbides is often measured in abrasion. In such tests it has been shown that the wear rate is inversely dependent on the material hardness. The sliding wear is even more of a surface phenomenon than a abrasion, making it difficult to predict friction and wear from bulk properties. This paper concentrates on the sliding wear of cemented carbides and elucidates some wear mechanisms. It is especially shown that a fragmenting wear mechanism of WC is very important for the description of wear of cemented carbides. (author)

  14. Alternative Fuels in Cement Production

    DEFF Research Database (Denmark)

    Larsen, Morten Boberg

    The substitution of alternative for fossil fuels in cement production has increased significantly in the last decade. Of these new alternative fuels, solid state fuels presently account for the largest part, and in particular, meat and bone meal, plastics and tyre derived fuels (TDF) accounted for...... the most significant alternative fuel energy contributors in the German cement industry. Solid alternative fuels are typically high in volatile content and they may differ significantly in physical and chemical properties compared to traditional solid fossil fuels. From the process point of view......, considering a modern kiln system for cement production, the use of alternative fuels mainly influences 1) kiln process stability (may accelerate build up of blockages preventing gas and/or solids flow), 2) cement clinker quality, 3) emissions, and 4) decreased production capacity. Kiln process stability in...

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

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    International Nuclear Information System (INIS)

    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

  17. Diagnostics Beamline for the SRF Gun Project

    CERN Document Server

    Kamps, T; Goldammer, K; Krämer, Dietrich; Kuske, P; Kuszynski, J; Lipka, D; Marhauser, F; Quast, T; Richter, R

    2005-01-01

    A superconducting rf photo electron injector (SRF gun) is currently under construction by a collaboration between BESSY, DESY, FZR and MBI. The project aims at the design and setup of an 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 pi 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 be...

  18. Beam-Based Procedures for RF Guns

    CERN Document Server

    Krasilnikov, Mikhail; Grabosch, H J; Hartrott, Michael; Hui Han, Jang; Miltchev, Velizar; Oppelt, Anne; Petrosyan, Bagrat; Staykov, Lazar; Stephan, Frank

    2005-01-01

    A wide range of rf photo injector parameters has to be optimized in order to achieve an electron source performance as required for linac based high gain FELs. Some of the machine parameters can not be precisely controlled by direct measurements, whereas the tolerance on them is extremely tight. Therefore, this should be met with beam-based techniques. Procedures for beam-based alignment (BBA) of the laser on the photo cathode as well as solenoid alignment have been developed. They were applied at the Photo Injector Test facility at DESY Zeuthen (PITZ) and at the photo injector of the VUV-FEL at DESY Hamburg. A field balance of the accelerating mode in the 1 ½ cell gun cavity is one of the key beam dynamics issues of the rf gun. Since no direct field measurement in the half and full cell of the cavity is available for the PITZ gun, a beam-based technique to determine the field balance has been proposed. A beam-based rf phase monitoring procedure has been developed as well.

  19. A Robust High Current Density Electron Gun

    Science.gov (United States)

    Mako, F.; Peter, W.; Shiloh, J.; Len, L. K.

    1996-11-01

    Proof-of-principle experiments are proposed to validate a new concept for a robust, high-current density Pierce electron gun (RPG) for use in klystrons and high brightness electron sources for accelerators. This rugged, long-life electron gun avoids the difficulties associated with plasma cathodes, thermionic emitters, and field emission cathodes. The RPG concept employs the emission of secondary electrons in a transmission mode as opposed to the conventional mode of reflection, i.e., electrons exit from the back face of a thin negative electron affinity (NEA) material, and in the same direction as the incident beam. Current amplification through one stage of a NEA material could be over 50 times. The amplification is accomplished in one or more stages consisting of one primary emitter and one or more secondary emitters. The primary emitter is a low current density robust emitter (e.g., thoriated tungsten). The secondary emitters are thin NEA electrodes which emit secondary electrons in the same direction as the incident beam. Specific application is targeted for a klystron gun to be used by SLAC with a cold cathode at 30-40 amps/cm^2 output from the secondary emission stage, a ~2 μs pulse length, and ~200 pulses/second.

  20. Diagnostics Beamline for the SRF Gun Project

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Overview of Plasma Guns for PLX

    Science.gov (United States)

    Witherspoon, F. Douglas; Bomgardner, Richard; Case, Andrew; Messer, Sarah; Brockington, Samuel; Wu, Linchun; Elton, Raymond; Hsu, Scott; Cassibry, Jason; Gilmore, Mark

    2010-11-01

    Plasma guns are being developed for use on the Plasma Liner Experiment (PLX) located at LANL. The collapsing plasma liner will be formed via merging of 30-60 dense, high Mach number plasma jets (n˜10^16-17 cm-3, M˜10--35, v˜50--70 km/s, rjet˜5 cm) in a spherically convergent geometry. Small parallel-plate railguns are being developed for this purpose. Each gun will operate at ˜300-600 kA peak current, and launch up to ˜8000 μg of high-Z plasma (Ar, Xe) using a ˜50 kJ pfn. We are now successfully operating with very fast gas valve injection of Ar, and have already achieved good performance of 1200 μg at 42 km/s, and 4000 μg at 20-25 km/s at low current. Work is underway to increase both the mass and velocity using higher current. We describe experimental development of the minirailguns and their present and projected performance. We also discuss options for modest size coaxial guns that might achieve the same performance and provide additional control of the plasmoid structure.

  2. Experimental Studies of Electrothermal Plasma Gun

    International Nuclear Information System (INIS)

    The aim of the present work is to study the capillary plasma discharge dynamics and characteristics. The capillary plasma device is a new technology for producing high density plasma after ablating the capillary wall using a pulsed electric power. An Electrothermal Plasma Gun (ETG) is composed of a capillary discharge tube made of Teflon operated with simple RLC circuit. The device called Electrothermal Gun (ETG) which is composed of 4 capacitors (70 μF, 10 kV, 1.28 μH) connected in parallel to a plasma source by means of one high power supply. The gun was operated in open air at discharge energies between 35 J - 3.5 kJ according to charging voltage. The work presented in this thesis covers the following items, 1- Measurements of the basic parameters and characterizations of the pretest results of the electrical circuits and capillary plasma discharge using Rogowski coil, voltage probe and Photomultiplier. 2- Material processing including (physics of the surface modifications, the morphology of the surface by using Scanning Electron Microscope (SEM) at different conditions, compositions of the materials by using X-ray Fluorescence (XRF), Micro hardness test and material particle deposition.

  3. Gas Gun Studies of Interface Wear Effects

    Science.gov (United States)

    Jackson, Tyler; Kennedy, Greg; Thadhani, Naresh

    2011-06-01

    The characteristics of interface wear were studied by performing gas gun experiments at velocities up to 1 km/s. The approach involved developing coefficients of constitutive strength models for Al 6061 and OFHC-Cu, then using those to design die geometry for interface wear gas gun experiments. Taylor rod-on-anvil impact experiments were performed to obtain coefficients of the Johnson-Cook constitutive strength model by correlating experimentally obtained deformed states of impacted samples with those predicted using ANSYS AUTODYN hydrocode. Simulations were used with validated strength models to design geometry involving acceleration of Al rods through a copper concentric cylindrical angular extrusion die. Experiments were conducted using 7.62 mm and 80 mm diameter gas guns. Differences in the microstructure of the interface layer and microhardness values illustrate that stress-strain conditions produced during acceleration of Al through the hollow concentric copper die, at velocities less than 800 m/s, result in formation of a layer via solid state alloying due to severe plastic deformation, while higher velocities produce an interface layer consisting of melted and re-solidified aluminum.

  4. Calcium Aluminate Cement Hydration Model

    Directory of Open Access Journals (Sweden)

    Matusinović, T.

    2011-01-01

    Full Text Available Calcium aluminate cement (AC is a very versatile special cement used for specific applications. As the hydration of AC is highly temperature dependent, yielding structurally different hydration products that continuously alter material properties, a good knowledge of thermal properties at early stages of hydration is essential. The kinetics of AC hydration is a complex process and the use of single mechanisms models cannot describe the rate of hydration during the whole stage.This paper examines the influence of temperature (ϑ=5–20 °C and water-to-cement mass ratio (mH /mAC = 0.4; 0.5 and 1.0 on hydration of commercial iron-rich AC ISTRA 40 (producer: Istra Cement, Pula, Croatia, which is a part of CALUCEM group, Figs 1–3. The flow rate of heat generation of cement pastes as a result of the hydration reactions was measured with differential microcalorimeter. Chemically bonded water in the hydrated cement samples was determined by thermo-gravimetry.Far less heat is liberated when cement and water come in contact for the first time, Fig. 1, than in the case for portland cement (PC. Higher water-to-cement ratio increases the heat evolved at later ages (Fig. 3 due to higher quantity of water available for hydration. A significant effect of the water-to-cement ratio on the hydration rate and hydration degree showed the importance of water as being the limiting reactant that slows down the reaction early. A simplified stoichiometric model of early age AC hydration (eq. (8 based on reaction schemes of principal minerals, nominally CA, C12A7 and C4AF (Table 1, was employed. Hydration kinetics after the induction period (ϑ < 20 °C had been successfully described (Fig. 4 and Table 2 by a proposed model (eq. (23 which simultaneously comprised three main mechanisms: nucleation and growth, interaction at phase boundary, and mass transfer. In the proposed kinetic model the nucleation and growth is proportional to the amount of reacted minerals (eq

  5. Effect of strain rate and water-to-cement ratio on compressive mechanical behavior of cement mortar

    Institute of Scientific and Technical Information of China (English)

    周继凯; 葛利梅

    2015-01-01

    Effects of strain rate and water-to-cement ratio on the dynamic compressive mechanical behavior of cement mortar are investigated by split Hopkinson pressure bar (SHPB) tests. 124 specimens are subjected to dynamic uniaxial compressive loadings. Strain rate sensitivity of the materials is measured in terms of failure modes, stress−strain curves, compressive strength, dynamic increase factor (DIF) and critical strain at peak stress. A significant change in the stress−strain response of the materials with each order of magnitude increase in strain rate is clearly seen from test results. The slope of the stress−strain curve after peak value for low water-to-cement ratio is steeper than that of high water-to-cement ratio mortar. The compressive strength increases with increasing strain rate. With increase in strain rate, the dynamic increase factor (DIF) increases. However, this increase in DIF with increase in strain rate does not appear to be a function of the water-to-cement ratio. The critical compressive strain increases with the strain rate.

  6. Assessment of Natural Radioactivity Levels of Cements and Cement Composites in the Slovak Republic

    OpenAIRE

    Adriana Eštoková; Lenka Palaščáková

    2013-01-01

    The radionuclide activities of 226Ra, 232Th and 40K and radiological parameters (radium equivalent activity, gamma and alpha indices, the absorbed gamma dose rate and external and internal hazard indices) of cements and cement composites commonly used in the Slovak Republic have been studied in this paper. The cement samples of 8 types of cements from Slovak cement plants and five types of composites made from cement type CEM I were analyzed in the experiment. The radionuclide activities in t...

  7. Assessment of the compatibility of wood and plastic with cement for their recycling in cement composites

    OpenAIRE

    Andrade, André De; Caldeira, Fernando

    2010-01-01

    The compatibility between maritime pine wood and cement, and between plastic (LDPE) and cement, was assessed for the recycling of wood and plastic in cement composites. Temperature vs. time profiles of cement setting were registered and compatibility indices were calculated. Results indicate that recycling of plastics in plastic-cement composites does not pose any questions regarding chemical compatibility. However, maritime pine hinders cement setting in some extent. So, in or...

  8. Design of an electron gun for terahertz radiation source

    International Nuclear Information System (INIS)

    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. (authors)

  9. Design of an electron gun for terahertz radiation source

    CERN Document Server

    Li, Ji; Hu, Tongning; Chen, Qushan; Feng, Guangyao; Shang, Lei; Li, Chenglong

    2013-01-01

    With the aim to obtain short-pulse bunches with high peak current for a terahertz radiation source, an EC-ITC (External-Cathode Independently Tunable Cells) RF gun was employed. As the external injecting electron source of the ITC RF gun, a gridded DC gun plays a key role, 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 is shown to overcome the strong space- charge force on the cathode, which is able to generate 6 {\\mu}s beam with 4.5A current successfully.

  10. High Peak Power Gyroklystron with an Inverted Magnetron Injection Gun

    Science.gov (United States)

    Read, Michael; Neilson, Jeff; Borchard, Philipp; Ives, Lawrence; Lawson, Wes

    2006-01-01

    This paper describes the design of a 25 MW, 30 GHz gyroklystron amplifier based on a coaxial RF structure. The design includes an inverted magnetron injection gun (MIG) for positioning and cooling the inner conductor. The gun produces a very low spread beam that contributes to a device efficiency of 54%. Details are given of the gun, RF structure, input and output couplers and collector.

  11. Continuity and Change in the American Gun Debate

    OpenAIRE

    Zimring, Franklin

    2001-01-01

    My paper traces the debates about firearms control over the three decades since I became involved in gun research in the late 1960s. The circumstances of public discourse about guns in the late 1960s were rich in sentiment and almost completely lacking in empirical data. Questions of firearms control were only episodically important at the national level, and the administration of federal gun laws was of minuscule importance prior to 1968.

  12. Guns, Grass, and God's Wrath, Colorado's Budget, Politics, and Elections

    OpenAIRE

    Berry, Michael J.

    2016-01-01

    The legalization of recreational marijuana and the fight over gun control grabbed the lion’s share of headlines in the state over the past year. With respect to the state budget, the tax revenue from marijuana sales should soon have significant budgetary implications. Though not as substantial, new gun control laws also have budgetary consequences since gun purchasers must now pay for the cost of background checks, where previously public funds were allocated for this purpose.

  13. America, guns and freedom: Part II — An international perspective

    OpenAIRE

    Faria, Miguel A.

    2012-01-01

    The need for reducing gun violence is discussed along with the necessity for citizens to assume some responsibility for protecting themselves, their families, and their property from criminal elements because the police cannot physically be everywhere to protect us all of the time. The problem of sensationalization of gun crimes by the media, multiple shootings by deranged individuals, accidents with firearms, suicide rates, and children with guns are discussed. The relationship of civilian d...

  14. Nail Gun Induced Open Head Injury: A Case Report

    OpenAIRE

    Oh, Hyun Ho; Kim, Young; Park, Sung Choon; Ha, Young Soo; Lee, Kyu Chang

    2014-01-01

    Increasing use of the nail gun has led to higher injury rates from the use of tools with sequential actuation. Nail gun injury can occur to various parts of the body. Very deep penetration in the brain can have fatal results. A 46-year-old male fired shots from a nail gun into his brain in a suicide attempt. This case demonstrated successful surgical management of the resultant open head injury.

  15. Design and manufacture of electron guns for welding

    International Nuclear Information System (INIS)

    In order to select the perveance and aperture of an electron beam for welding, a method has been developed. It allows a high power density, a low probability of breakdown occurence during the welding process. It has been applied to design and realize three EB guns: an early 100kW prototype gun, two guns for tube to plate welding in the horizontal vertical mode: on thick sections, for heat exchanger assemblies

  16. Structural Optimization of Machine Gun Based on Dynamic Stability Concept

    Institute of Scientific and Technical Information of China (English)

    LI Yong-jian; WANG Rui-lin; ZHANG Ben-jun

    2008-01-01

    Improving the firing accuracy is a final goal of structural optimization of machine guns. The main factors which affect the dispersion accuracy of machine gun are analyzed. Based on the concept of dynamic stability, a structural optimization model is built up, and the sensitivity of dispersion accuracy to design variables is analyzed. The optimization results of a type of machine gun show that the method is valid, feasible, and can be used as a guide to the structural optimization of other automatic weapons.

  17. Alternating Current All-electrical Gun Control System in Tanks

    OpenAIRE

    Zang Kemao; Ma Xiaojun; Li Changbing

    2004-01-01

    The ac all-electrical gun control system is composed of permanent magnetic synchronous machine-drive control systems and the ball-screw by replacing the complicated electrohydraulic systems. At the same time, the variable-structure system with sliding modes makes the gun control systems to have higher performances using the only rate flexure gyroscope. Thereby, vehicle hull gyroscope and angular gyroscope are left out.The new ac all-electrical gun control systems developed are reduced by 40 p...

  18. Violence, Guns, and Drugs: A Cross-Country Analysis.

    OpenAIRE

    Jeffrey A. Miron

    2001-01-01

    Violence rates differ dramatically across countries. A widely held view is that these differences reflect differences in gun control and/or gun availability, and certain pieces of evidence appear consistent with this hypothesis. A more detailed examination of this evidence suggests that the role of gun control/availability is not compelling. This more detailed examination, however, does not provide an alternative explanation for cross-country differences in violence. This paper suggests that ...

  19. Nail Gun Induced Open Head Injury: A Case Report.

    Science.gov (United States)

    Oh, Hyun Ho; Kim, Young; Park, Sung Choon; Ha, Young Soo; Lee, Kyu Chang

    2014-10-01

    Increasing use of the nail gun has led to higher injury rates from the use of tools with sequential actuation. Nail gun injury can occur to various parts of the body. Very deep penetration in the brain can have fatal results. A 46-year-old male fired shots from a nail gun into his brain in a suicide attempt. This case demonstrated successful surgical management of the resultant open head injury. PMID:27169051

  20. The bird in hand: A feasible strategy for gun control

    OpenAIRE

    Moore, Mark H

    1982-01-01

    Policy analysis has failed to guide gun control policy away from its current impasse because analysts have avoided facing several crucially important features of the current reality: the existence of some widely held values in the United States public that favor the possession of guns; the limitations on the ability of public agencies in the United States to enforce restraints on the possession of handguns; and the implications of the fact that so many guns are already in the hands of the pub...

  1. The Effects of Gun Prevalence on Burglary: Deterrence vs Inducement

    OpenAIRE

    Cook, Philip J.; Jens Ludwig

    2002-01-01

    The proposition that widespread gun ownership serves as a deterrent to residential burglary is widely touted by advocates, but the evidence is weak, consisting of anecdotes, interviews with burglars, casual comparisons with other countries, and the like. A more systematic exploration requires data on local rates of gun ownership and of residential burglary, and such data have only recently become available. In this paper we exploit a new well-validated proxy for local gun-ownership prevalence...

  2. Evaluation of a Light Machine Gun Using Analytic Network Process

    OpenAIRE

    Emel Kizilkaya Aydogan; Cevriye Gencer; Saim Aytürk

    2009-01-01

    The light machine guns are among the significant fire support guns for the infantry. While the rapid advances in technology are improving the quality, these are also increasing the diversity, increasing the research carried out in the existing institutions and organisations.This is making the decision problem faced during the process complicated as well. To solve such problems, multiple criteria decision making methods are used. In this study, the selection of the light machine guns has been ...

  3. Hoist technology of a new agile naval gun shell-feeding system

    Institute of Scientific and Technical Information of China (English)

    LUO A-ni; LIU He-ping; SONG Hong-xia; HU Sheng-hai; ZHANG Jia-tai

    2006-01-01

    Shell-feeding velocity is an important factor affecting naval gun shooting capacity. An agile shell-feeding system was designed to ensure quick implementation of the shell-feeding task. Based on composition of the agile shell-feeding system, hoist technology was studied. Working principles were discussed and the hydraulic pressure system of the hoist was constructed. The hydraulic pressure cylinder and the accumulator were analyzed and calculated. Finally, PRO/E and ADAMS were used to simulate the hoist and its hydraulic system. It was found that this type of virtual prototype provides a good method to actualize a physical prototype.

  4. Manufacture and properties of fluoride cement

    Science.gov (United States)

    Malata-Chirwa, Charles David

    This research work aimed at characterising composition, hydration and physical properties of fluoride cement, by studying samples of the cement obtained from Malawi, and comparing them to ordinary Portland cement. By confirming the suitable characteristics of fluoride cement through this work, the results of the research work provide a good basis for the wider adoption of fluoride cement as an alternative to ordinary Portland cement, especially in developing economies. Numerous accounts have been cited regarding the production and use of fluoride cement. Since there have not been conclusive agreement as to its properties, this study was limited to the theories of successful incorporation of fluoride compounds in the manufacture of fluoride cement. Hence, the properties and characteristics reported in this study relate to the cement currently manufactured in Malawi, and, on a comparative basis only, to that manufactured in other parts of the world. Samples of the fluoride cement used in the study were obtained by synthetic manufacture of the cement using common raw materials for the manufacture of fluoride cement that is limestone, silica sand, and fluorspar. These samples were subjected to several comparative tests used to characterise cements including examination under x-ray diffractometer, scanning electron microscopy and tests for setting time and compressive strength. Under similar laboratory conditions, it was possible to prove that fluoride cement hardens more rapidly than ordinary Portland cement. Also observed during the experimental work is that fluoride cement develops higher compressive strengths than ordinary Portland cement. The hardening and setting times are significantly different between the two cements. Also the nature of the hydration products, that is the microstructural development is significantly different in the two cements. The differences brought about between the two cements are because of the presence of fluorine during the clinkering

  5. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  6. Low pH Cements

    International Nuclear Information System (INIS)

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit ≤ 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio ≤ 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  7. Gun Buybacks and Firm Behavior: Do Buyback Programs Really Reduce the Number of Guns?

    OpenAIRE

    Gregory E. Goering

    2011-01-01

    We suppose that guns or firearms are subject to an anticipated future buyback program undertaken by the government. A simple linear demand durable-goods monopoly model is then analyzed where the durable-good manufactured is a firearm that lasts for two-periods. The model is calibrated so that buyers are indifferent between selling (participating in the buyback program) or holding the gun in the future period. This allows us to focus solely on the firm¡¯s behavior. We find, among other things,...

  8. Generation of Overpressure by Cementation of Pore Space in Sedimentary Rocks

    Energy Technology Data Exchange (ETDEWEB)

    Wangen, Magnus

    2000-09-01

    Overpressure build-up is studied when the main cause for porosity reduction is cementation of the pore space source locally. The average porosity reduction for siliclastic sediments is modeled with n'th order kinetics. It is shown that the overpressure in one layer at a constant depth will decrease exponentially with time in the case of first order kinetics for the porosity reduction. The overpressure is studied in one layer subjected to cementation during constant burial along a thermal gradient. A small overpressure build-up is shown above the window for cementation, with a steep rise in overpressure in the upper part of the window. The overpressure build-up is then seen to decrease rapidly towards the end of the window for cementation. Overpressure build-up is also studied when cementation is the main cause for porosity reduction in the entire column of sediments during deposition and burial. The overpressure regime characterized by gravity numbers larger than one is studied. This regime corresponds to low or moderate overpressures in case of mechanical compaction. Cementation is shown to imply a steep pressure build-up in the window of cementation, which will easily exceed the lithostatic pressure. The porosity loss due to cementation is seen to have a strong impact on the permeability, which leads to the formation of a pressure seal. Also most of the potential for fluid expulsion is exhausted below the seal, because most of the porosity is cemented up, the permeability of seal is sufficiently low for hydrofracturing to take place. This scenario is consistent with overpressure observations in many wells. (author)

  9. A flow cryostat for cooling of eight independent pipe guns

    DEFF Research Database (Denmark)

    Sørensen, H.; Hansen, J.E.; Sass, B.

    1991-01-01

    A flow cryostat allowing independent cooling of eight pipe guns in a multishot deuterium pellet injector is described. The pipe guns are placed symmetrically around the flow cryostat and with a liquid helium consumption of 4-5 l/h the cooling is sufficient for simultaneous formation of eight...... pellets at 8-9 K with a diameter of 2.1 mm containing up to 8 x 10(20) atoms/pellet. The thermal interaction between the eight pipe guns is sufficiently low to allow successive firing of the guns with time intervals of up to 1 s....

  10. Development of beam diagnostic devices for characterizing electron guns

    International Nuclear Information System (INIS)

    The electron guns for the DC accelerators and RF Linacs are designed and developed at EBC/APPD/BARC, Kharghar. These electron guns need to be characterized for its design and performance. Two test benches were developed for characterizing the electron guns. Various beam diagnostic devices for measuring beam currents and beam sizes were developed. Conical faraday cup, segmented faraday cup, slit scanning bellows movement arrangement, multi-plate beam size measurement setup, multi- wire beam size measurement setup, Aluminum foil puncture assembly etc. were developed and used. The paper presents the in-house development of various beam diagnostics for characterizing electron guns and their use. (author)

  11. Development of an electron gun for the KEK positron generator

    International Nuclear Information System (INIS)

    In the KEK Positron Generator, a semi-long pulsed beam (∼40ns) has turned out to be suitable for effective positron injection into the PF storage ring. However, to use the semi-long pulsed beam, there was a problem concerning the cathode lifetime of the gun. Thus, a new gun has been developed with a dispenser cathode, Y-796(EIMAC); the characteristics of this gun have been investigated. This new gun has been used since October 1988 and has continued to produce constant current of about 12A without having to exchange its cathode. Thus, the cathode lifetime has been remarkably improved. (author) 6 refs., 7 figs

  12. Lack of inhibiting effect of oil emplacement on quartz cementation: Evidence from Cambrian reservoir sandstones, Paleozoic Baltic Basin

    DEFF Research Database (Denmark)

    Molenaar, Nicolaas; Cyziene, Jolanta; Sliaupa, Saulius;

    2008-01-01

    cementation is derived from internal sources. Rather, in spite of large variation in porosity and quartz cement content, a regular pattern of porosity decrease is related to increasing temperature or depth. The observed heterogeneity is due to local factors that influence the precipitation of quartz cement......Currently, the question of whether or not the presence of oil in sandstone inhibits quartz cementation and preserves porosity is still debated. Data from a number of Cambrian sandstone oil fields and dry fields have been studied to determine the effects of oil emplacement on quartz cementation. The......, including sandstone architecture, i.e., distribution of shales within the sandstone bodies, and sandstone thickness. Heterogeneity is inherent to sandstone architecture and to the fact that silica for quartz cementation is derived from heterogeneously distributed local pressure solution. Models predicting...

  13. Performance evaluation of self-breakdown-based single-gap plasma cathode electron gun

    Indian Academy of Sciences (India)

    Niraj Kumar; Nalini Pareek; Udit Narayan Pal; Deepak Kumar Verma; Jitendra Prajapati; Mahesh Kumar; Bharat Lal Meena; Ram Prakash

    2014-06-01

    This paper presents the experimental studies on self-breakdown-based single-gap plasma cathode electron (PCE) gun (5–20 kV/50–160 A) in argon, gas atmosphere and its performance evaluation based on particle-in-cell (PIC) simulation code `OOPIC-Pro’.The PCE-Gun works in conducting phase (low energy, high current) of pseudospark discharge. It produces an intense electron beam, which can propagate more than 200 mm in the drift space region without external magnetic field. The profile of this beam in the drift space region at different breakdown conditions (i.e., gas pressures and applied voltages) has been studied and the experimental results are compared with simulated values. It is demonstrated that ∼30% beam current is lost during the propagation possibly due to space charge neutralization and collisions with neutral particles and walls.

  14. Ignition Features of Plasma-Beam Discharge in Gas-Discharge Electron Gun Operation

    Directory of Open Access Journals (Sweden)

    Valery A. Tutyk

    2013-01-01

    Full Text Available The current paper presents the results of experimental researches to determine the mode features of plasma-beam discharge (PBD generation by an electron beam injected by a low-vacuum gasdischarge electron gun (LGEG with the cold cathode and hollow anode on the basis of the high-voltage glow discharge and in the range of helium pressure of P ? 10 ÷ 130 Pa. The PBD boundaries and their dependences on parameters of an electron beam are found. The influence of PBD on parameters of low-vacuum gas-discharge electron gun is revealed. It causes an avalanche increase of electron beam current and burning of plasma-beam discharge in the whole space of the vacuum chamber volume and generation of electromagnetic radiation is revealed. Achieved results will be used for implementation of various vacuum technologies in the medium of reaction gas and generated electromagnetic radiation.

  15. Piezoresistivity in Carbon Fiber Reinforced Cement Based Composites

    Institute of Scientific and Technical Information of China (English)

    Bing CHEN; Keru WU; Wu YAO

    2004-01-01

    The resu lts of some i nteresti ng investigation on the piezoresistivity of ca rbon fi ber reinforced cement based com posites (CFRC) are presented with the prospect of developing a new nondestructive testing method to assess the integrity of the composite. The addition of short carbon fibers to cement-based mortar or concrete improves the structural performance and at the same time significantly decreases the bulk electrical resistivity. This makes CFRC responsive to the smart behavior by measuring the resistance change with uniaxial pressure. The piezoresistivity of CFRC under different stress was studied, at the same time the damage occurring inner specimens was detected by acoustic emission as well. Test results show that there exists a marking pressure dependence of the conductivity in CFRC, in which the so-called negative pressure coefficient of resistive (NPCR) and positive pressure coefficient of resistive (PPCR) are observed under low and high pressure. Under constant pressures, time-dependent resistivity is an outstanding characteristic for the composites, which is defined as resistance creep. The breakdown and rebuild-up process of conductive network under pressure may be responsible for the pressure dependence of resistivity.

  16. Investigation of the volume instability of ion exchange resins embedded in cement

    International Nuclear Information System (INIS)

    Ion exchange resins (IERs) are widely used by nuclear industry to decontaminate radioactive effluents. Spent resins have to be conditioned and the cementation process is adequate, relatively simple and inexpensive. However, several specificities of IERs have to be taken into account to design a cement formula: -) their ability to exchange ions with the cementitious medium, which may influence the cement hydration process, -) their low mechanical strength, which strongly weakens the compressive strength of the solidified waste forms, -) their strong dimensional variations which can, under severe conditions, induce swelling and cracking of the cement-based matrix. These dimensional variations can result from various processes: osmotic pressure and ion exchange in saturated medium, relative humidity variations in de saturated medium. Free deformations of IERs are measured as a function of different parameters: nature of the ions fixed on the functional groups, ionic strength of the aqueous solution in which the resins are immersed, water saturation degree of the resins. Particular attention is also paid to the quantification of swelling pressures induced by resins in a confined environment, as it may be the case in the cement-based matrix. Cements containing high amounts of blast-furnace slag are more appropriate than Portland cement (OPC) to solidify cationic IERs saturated with sodium or potassium. The rapid expansion observed during the first days of hydration with OPC can indeed be strongly reduced with the blended binders

  17. Laboratory Test on Long-Term Deterioration of Cement Soil in Seawater Environment

    Institute of Scientific and Technical Information of China (English)

    杨俊杰; 闫楠; 刘强; 张玥宸

    2016-01-01

    Laboratory tests were conducted to study the effects of curing time, cement ratio and seawater pressure on cement soil deterioration formed at simulative marine soft clay sites. Deterioration depth was determined on the basis of characteristics of penetration resistance and penetration depth curves, and the deterioration depth of cement soil with the cement ratio of 7%, reached 31.8 mm after 720 d. Results of research indicated that deterioration ex-tended quickly under seawater environment and the deterioration depth increased with the prolonging curing time. In addition, the water pressure could speed up deterioration. With the increase of cement content, the strength of cement soil increased obviously. At the same time, the deterioration depth decreased significantly. The concentra-tion of calcium ion in the cement stabilized soil increased with the increase of depth, while that of magnesium ion gradually decreased. The variations were consistent with energy dispersive spectrometer(EDS)analysis results, and the calcium concentration with depth was in a good consistency with strength distribution at long term. The results showed that the deterioration became more serious with the curing time, and it was related to calcium leaching.

  18. Coaxial plasma guns as injectors of high beta linear theta pinches

    International Nuclear Information System (INIS)

    A brief review of research on coaxial plasma guns and their use is given. Some problems and possibilities of using this gun for beam injection experiments are pointed out. Some scaling laws for gun energy are described

  19. Prevalence of youth access to alcohol or a gun in the home

    OpenAIRE

    Swahn, M; Hammig, B; Ikeda, R

    2002-01-01

    Objectives: To estimate the national prevalence of youth access to alcohol, a gun, or both alcohol and a gun, in their home and to describe the demographic characteristics associated with access to either alcohol or a gun.

  20. Effects of gun admonitions on the behaviors and attitudes of school-aged boys.

    Science.gov (United States)

    Hardy, Marjorie S

    2003-10-01

    Gun-safety programs frequently warn children not to touch guns with little consideration that the messages may enhance the allure of the guns. In the current study, boys rated and ranked their preference for a gun in comparison with other desirable objects. One week later, when left alone in the room with the objects, they were forbidden to touch either the gun or some other object. Observations of their behavior and reevaluation of their attitudes followed. Although the boys forbidden to touch the gun did not report an increased preference for it, all participants were significantly more likely to touch the forbidden gun than to touch other forbidden objects. Age, parent- and coach-reported simulated gun-play, and coach-reported risky behavior predicted gun-touching behavior. The results of the current study indicate that guns hold a unique allure and cast further doubt on the ability of gun admonitions to keep children safe around guns. PMID:14578696

  1. The effect of pressure changes during simulated diving on the pull out strength of glass fiber posts

    Directory of Open Access Journals (Sweden)

    Meenal Nitin Gulve

    2013-01-01

    Conclusion: Dentist should consider using resin reinforced glass ionomer or resin cement, for the cementation of glass fiber post, for the patients such as divers, who are likely to be exposed to pressure cycling.

  2. The effect of cement creep and cement fatigue damage on the micromechanics of the cement-bone interface.

    Science.gov (United States)

    Waanders, Daan; Janssen, Dennis; Mann, Kenneth A; Verdonschot, Nico

    2010-11-16

    The cement-bone interface provides fixation for the cement mantle within the bone. The cement-bone interface is affected by fatigue loading in terms of fatigue damage or microcracks and creep, both mostly in the cement. This study investigates how fatigue damage and cement creep separately affect the mechanical response of the cement-bone interface at various load levels in terms of plastic displacement and crack formation. Two FEA models were created, which were based on micro-computed tomography data of two physical cement-bone interface specimens. These models were subjected to tensile fatigue loads with four different magnitudes. Three deformation modes of the cement were considered: 'only creep', 'only damage' or 'creep and damage'. The interfacial plastic deformation, the crack reduction as a result of creep and the interfacial stresses in the bone were monitored. The results demonstrate that, although some models failed early, the majority of plastic displacement was caused by fatigue damage, rather than cement creep. However, cement creep does decrease the crack formation in the cement up to 20%. Finally, while cement creep hardly influences the stress levels in the bone, fatigue damage of the cement considerably increases the stress levels in the bone. We conclude that at low load levels the plastic displacement is mainly caused by creep. At moderate to high load levels, however, the plastic displacement is dominated by fatigue damage and is hardly affected by creep, although creep reduced the number of cracks in moderate to high load region. PMID:20692663

  3. Cementation of Loose Sand Particles based on Bio-cement

    Institute of Scientific and Technical Information of China (English)

    RONG Hui; QIAN Chunxiang

    2014-01-01

    Loose sand particles could be cemented to sandstone by bio-cement (microbial induced magnesium carbonate). The bio-sandstone was firstly prepared, and then the compressive strength and the porosity of the sandstone cemented by microbial induced magnesium carbonate were tested to characterize the cementation effectiveness. In addition, the formed mineral composition and the microstructure of bio-sandstone were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The experimental results show that the feasibility of binding loose sand particles using microbial induced magnesium carbonate precipitation is available and the acquired compressive strength of bio-sandstone can be excellent at certain ages. Moreover, the compressive strength and the porosity could be improved with the increase of microbial induced magnesium carbonate content. XRD results indicate that the morphology of magnesium carbonate induced by microbe appears as needles and SEM results show that the cementation of loose sand particles to sandstone mainly relies on the microbial induced formation of magnesium carbonate precipitation around individual particles and at particle-particle contacts.

  4. Repetitive two-stage light gas gun for high-speed pellet injection

    International Nuclear Information System (INIS)

    A repetitive two-stage light gas gun for high-speed pellet injection has been developed at Oak Ridge National Laboratory. In general, applications of the two-stage light gas gun have been limited to only single shots, with a finite time (at least minutes) needed for recovery and preparation for the next shot. The new device overcomes problems associated with repetitive operation, including rapidly evacuating the propellant gases, reloading the gun breech with a new projectile, returning the piston to its initial position, and refilling the first- and second-stage gas volumes to the appropriate pressure levels. In addition, some components are subjected to and must survive severe operating conditions, which include rapid cycling to high pressures and temperatures (up to thousands of bars and thousands of kelvins) and significant mechanical shocks. Small plastic projectiles (4 mm nominal size) and helium gas have been used in the prototype device, which was equipped with a 1-m-long pump tube and a 1-m-long gun barrel, to demonstrate repetitive operation (up to 1 Hz) at relatively high pellet velocities (up to 3000 m/s). The highest experimental velocity is twice that available from conventional repeating single-stage pneumatic injectors that accelerate frozen pellets of hydrogen isotopes and are now used to fuel magnetically confined plasmas for controlled thermonuclear fusion research. Also, the pellet test repetition rate of 1 Hz is relevant for fueling applications on future large fusion research devices. The equipment is described, and experimental results are presented and compared with calculated results from gas dynamics models

  5. Repetitive two-stage light gas gun for high-speed pellet injection

    Science.gov (United States)

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

    1991-08-01

    A repetitive two-stage light gas gun for high-speed pellet injection has been developed at Oak Ridge National Laboratory. In general, applications of the two-stage light gas gun have been limited to only single shots, with a finite time (at least minutes) needed for recovery and preparation for the next shot. The new device overcomes problems associated with repetitive operation, including rapidly evacuating the propellant gases, reloading the gun breech with a new projectile, returning the piston to its initial position, and refilling the first- and second-stage gas volumes to the appropriate pressure levels. In addition, some components are subjected to and must survive severe operating conditions, which include rapid cycling to high pressures and temperatures (up to thousands of bars and thousands of kelvins) and significant mechanical shocks. Small plastic projectiles (4 mm nominal size) and helium gas have been used in the prototype device, which was equipped with a 1-m-long pump tube and a 1-m-long gun barrel, to demonstrate repetitive operation (up to 1 Hz) at relatively high pellet velocities (up to 3000 m/s). The highest experimental velocity is twice that available from conventional repeating single-stage pneumatic injectors that accelerate frozen pellets of hydrogen isotopes and are now used to fuel magnetically confined plasmas for controlled thermonuclear fusion research. Also, the pellet test repetition rate of 1 Hz is relevant for fueling applications on future large fusion research devices. The equipment is described, and experimental results are presented and compared with calculated results from gas dynamics models.

  6. ANALYSIS OF MECHANICAL PROPERTIES OF HYDROTHERMALLY CURED HIGH STRENGTH CEMENT MATRIX FOR TEXTILE REINFORCED CONCRETE

    OpenAIRE

    Ondřej Holčapek; Filip Vogel; Petr Konvalinka

    2015-01-01

    The main objective of this article is to describe the influence of hydrothermal curing conditions in an autoclave device (different pressure and temperature), which took place at various ages of a fresh mixture (cement matrix – CM, and fibre-reinforced cement matrix – FRCM), on textile reinforced concrete production. The positive influence of autoclaving has been evaluated through the results of physical and mechanical testing – compressive strength, flexural strength, bulk density and dynami...

  7. Cyclic Gun--Human Evolution: Soldiers, Guns, Machine Logic, and the Future

    Science.gov (United States)

    Blackmore, Tim

    2006-01-01

    Guns, slug-throwing weapons, have evolved as humans have increased their grasp of the mechanical arts. In the near future, however, it seems likely that soldiers' rifles operating at punishing cyclic rates of fire face the limits of physics and materials science--heat and speed will cost accuracy and distance. This article considers not only the…

  8. Action Alters Object Identification: Wielding a Gun Increases the Bias to See Guns

    Science.gov (United States)

    Witt, Jessica K.; Brockmole, James R.

    2012-01-01

    Stereotypes, expectations, and emotions influence an observer's ability to detect and categorize objects as guns. In light of recent work in action-perception interactions, however, there is another unexplored factor that may be critical: The action choices available to the perceiver. In five experiments, participants determined whether another…

  9. Testing a GaAs cathode in SRF gun

    Energy Technology Data Exchange (ETDEWEB)

    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

  10. Filament free electron gun and ISU generator

    International Nuclear Information System (INIS)

    Electron Beam Curing consists of the use of accelerated electrons for the creation of chemical reactions such as polymerisation cross linking or grafting. Electron guns use thermal emission to produce electrons before accelerating them towards the products to be cured. In the range of energy from 150 kV to 300 kV, A.I.D. has developed a new machine that is more adapted to industrial uses. A filament free system that is more reliable, tougher and easier to maintain than conventional systems, is described. The ISU (Induction Spire Unique) high voltage generator is also described briefly. (U.K.)

  11. Pulse shaper for electron gun control

    International Nuclear Information System (INIS)

    Modulation of electron gun of spectrometer for surface diagnostics allows to proceed to recording of N(E) from recording of the first derivative of secondary-emitted electron energy redistribution, dN/dE(E) with minimal modernization of the available modernization of the available receiving channel of spectrometer. Circuit with inductive bond ensures galvanic decoupling of the former by inlet and outlet. Irial spectra of characteristical losses in N(E) form obtained at modulation of the electron primary beam using the developed pulse former, and in dN/dE(E) form-using modulation of braking potential, are presented. 9 refs.; 2 figs

  12. Gas powered fluid gun with recoil mitigation

    Science.gov (United States)

    Grubelich, Mark C; Yonas, Gerold

    2013-11-12

    A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

  13. Smart gun technology requirements preliminary report

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, D.R.; Brandt, D.J.; Tweet, K.D.

    1995-05-01

    Goal of the Smart Gun Technology project is to eliminate the capability of an unauthorized user from firing a law enforcement officer`s firearm by implementing user-recognizing-and-authorizing surety technologies. This project is funded by the National Institute of Justice. This document reports the projects first objective: to find and document the requirements for a user-recognizing-and-authorizing firearm technology that law enforcement officers will value. This report details the problem of firearm takeaways in law enforcement, the methodology used to develop the law enforcement officers` requirements, and the requirements themselves.

  14. Nanosecond modulator of an electron gun

    International Nuclear Information System (INIS)

    The nanosecond modulator of an electron gun is developed for forming an electron beam with small emittance, necessary for generating the laser on free electrons. The block-diagram of the modulator is presented. The modulator consists of an optical receiver, two formers, two high-frequency power keys, diode with the DNZ charge storage and storage line. The modulator is positioned inside the timer container in the SF6 insulating gas medium under the 300 kV potential. The measured pulsation of the modulator output pulses is below 50 ps. The modulator operates reliably by the high-voltage breakdowns in the system

  15. Gas powered fluid gun with recoil mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Grubelich, Mark C.; Yonas, Gerold

    2016-03-01

    A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

  16. Numerical Simulations of Thermionic Electron Guns

    Czech Academy of Sciences Publication Activity Database

    Jánský, Pavel; Lencová, Bohumila; Zlámal, J.

    Brno: Institute of Scientific Instruments AS CR, v.v.i, 2008 - (Mika, F.), s. 51-52 ISBN 978-80-254-0905-3. [International Seminar on Recent Trends in Charged Particle Optics and Surface Physics Instrumentation /11./. Skalský dvůr (CZ), 14.07.2008-18.07.2008] R&D Projects: GA AV ČR IAA100650805 Institutional research plan: CEZ:AV0Z20650511 Keywords : electron emission * electron gun * space charge * numerical simulations Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  17. Air pollution: a smoking gun for cancer

    OpenAIRE

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

    2014-01-01

    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...

  18. Ion gun operations at high altitudes

    OpenAIRE

    Werner, Paul W.

    1988-01-01

    Experiments in charge control were conducted on the P78-2 (SCATHA) satellite as part of a program on spacecraft charging at high altitudes. Experiments with the SCATHA ion gun were monitored by charged particle detectors and the electric field experiment. It was found that the electric field experiment could be used to measure satellite potential during ion beam emission in sunlight and eclipse. Unneutralized ion beam emission in high energy (1-2 KeV) and high current (1-2 mA) modes resulted ...

  19. Characterizing Reactive Flow Paths in Fractured Cement

    Science.gov (United States)

    Wenning, Q. C.; Huerta, N. J.; Hesse, M. A.; Bryant, S. L.

    2011-12-01

    Geologic carbon sequestration can be a viable method for reducing anthropogenic CO2 flux into the atmosphere. However, the technology must be economically feasible and pose acceptable risk to stakeholders. One key risk is CO2 leakage out of the storage reservoir. Potential driving forces for leakage are the overpressure due to CO2 injection and the buoyancy of free phase CO2. Potential hazards of leakage are contamination of Underground Sources of Drinking Water or the atmosphere and would be deemed an unacceptable risk. Wells potentially provide a fast path for leakage from the reservoir. While the well's cement casing is reactive with CO2 and CO2-saturated brine, the low cement matrix permeability and slow diffusion rate make it unlikely that CO2 will escape through a properly constructed wellbore. However, highly permeable fractures with micrometer scale apertures can occur in cement casings. Reactions that occur in the flow in these fractures can either be self-limiting or self-enhancing. Therefore, understanding the reactive flow is critical to understanding of leakage evolution through these fractures. The goal of our work is to characterize the modification of the flow paths in the fracture due to reaction with acidic brine. With this aim we have characterized both the initial flow path of un-reactive flow and the final flow path after introduction of low-pH acid along the same fracture. Class H cement cores 3-6 cm in length and 2.5 cm diameter are created and a single natural and unique fracture is produced in each core using the Brazilian method. Our experimental fluid is injected at a constant rate into the cement core housed in a Hassler Cell under confining pressure. A solution of red dye and deionized water is pumped through the fracture to stain the un-reactive flow paths. Deionized water is then pumped through the core to limit diffusion of the dye into non-flowing portions of the fracture. After staining the initial flow path, low pH water due to

  20. Gun possession among American youth: a discovery-based approach to understand gun violence.

    Directory of Open Access Journals (Sweden)

    Kelly V Ruggles

    Full Text Available OBJECTIVE: To apply discovery-based computational methods to nationally representative data from the Centers for Disease Control and Preventions' Youth Risk Behavior Surveillance System to better understand and visualize the behavioral factors associated with gun possession among adolescent youth. RESULTS: Our study uncovered the multidimensional nature of gun possession across nearly five million unique data points over a ten year period (2001-2011. Specifically, we automated odds ratio calculations for 55 risk behaviors to assemble a comprehensive table of associations for every behavior combination. Downstream analyses included the hierarchical clustering of risk behaviors based on their association "fingerprint" to 1 visualize and assess which behaviors frequently co-occur and 2 evaluate which risk behaviors are consistently found to be associated with gun possession. From these analyses, we identified more than 40 behavioral factors, including heroin use, using snuff on school property, having been injured in a fight, and having been a victim of sexual violence, that have and continue to be strongly associated with gun possession. Additionally, we identified six behavioral clusters based on association similarities: 1 physical activity and nutrition; 2 disordered eating, suicide and sexual violence; 3 weapon carrying and physical safety; 4 alcohol, marijuana and cigarette use; 5 drug use on school property and 6 overall drug use. CONCLUSIONS: Use of computational methodologies identified multiple risk behaviors, beyond more commonly discussed indicators of poor mental health, that are associated with gun possession among youth. Implications for prevention efforts and future interdisciplinary work applying computational methods to behavioral science data are described.

  1. A modified PMMA cement (Sub-cement) for accelerated fatigue testing of cemented implant constructs using cadaveric bone.

    Science.gov (United States)

    Race, Amos; Miller, Mark A; Mann, Kenneth A

    2008-10-20

    Pre-clinical screening of cemented implant systems could be improved by modeling the longer-term response of the implant/cement/bone construct to cyclic loading. We formulated bone cement with degraded fatigue fracture properties (Sub-cement) such that long-term fatigue could be simulated in short-term cadaver tests. Sub-cement was made by adding a chain-transfer agent to standard polymethylmethacrylate (PMMA) cement. This reduced the molecular weight of the inter-bead matrix without changing reaction-rate or handling characteristics. Static mechanical properties were approximately equivalent to normal cement. Over a physiologically reasonable range of stress-intensity factor, fatigue crack propagation rates for Sub-cement were higher by a factor of 25+/-19. When tested in a simplified 2 1/2-D physical model of a stem-cement-bone system, crack growth from the stem was accelerated by a factor of 100. Sub-cement accelerated both crack initiation and growth rate. Sub-cement is now being evaluated in full stem/cement/femur models. PMID:18774136

  2. Seating load parameters impact on dental ceramic reinforcement conferred by cementation with resin-cements.

    LENUS (Irish Health Repository)

    Addison, Owen

    2010-09-01

    Cementation of all-ceramic restorations with resin-cements has been demonstrated to reduce the incidence of fracture in service. The aim was to investigate the influence of loading force and loading duration applied during cementation on the reinforcement conferred by a resin-cement on a leucite reinforced glass-ceramic.

  3. Retention of Root Canal Posts: Effect of Cement Film Thickness, Luting Cement, and Post Pretreatment

    DEFF Research Database (Denmark)

    Sahafi, Alireza; Benetti, Ana Raquel; Peutzfeldt, Anne; Flury, Simon

    2015-01-01

    The aim of this study was to investigate the effect of the cement film thickness of a zinc phosphate or a resin cement on retention of untreated and pretreated root canal posts. Prefabricated zirconia posts (CosmoPost: 1.4 mm) and two types of luting cements (a zinc phosphate cement [DeTrey Zinc...

  4. [Antimicrobial activity of orthodontic band cements].

    Science.gov (United States)

    Pavic, J; Arriagada, M; Elgueta, J; García, C

    1990-01-01

    The prevalence of enamel decalcification and caries beneath orthodontic bands, has indicated the need for a new enamel binding adhesive orthodontic cement. The purpose of this study was to evaluate the antimicrobial activity, in vitro, on Streptococcus mutans and Lactobacillus, acidophillus, of three materials used to cements the orthodontic bands. The cements studied were: Zinc phosphate cement, Glass-ionomer cement, and Policarboxylate cement. Thirty petri plates were seeded with S. mutans, and thirty with L. acidophillus; on each plate three pellet were placed, one of each cement studied. Petri plates were incubated under microaerophilic conditions at 37 C, and checked at 72 hrs. for Streptococcus, mutans, and four days for Lactobacillus acidophillus to evaluate the inhibition zone. The results were tabulated for each material. It was demonstrated that exists important variations in the antimicrobial properties of the materials studied, as in the microbial sensitivity to these cements. PMID:2135908

  5. Gun Access and Safety Practices among Older Adults

    Directory of Open Access Journals (Sweden)

    Hillary D. Lum

    2016-01-01

    Full Text Available Background. Given high rates of gun ownership among older adults, geriatric providers can assess firearm safety practices using a “5 Ls” approach: Locked; Loaded; Little children; feeling Low; and Learned owner. This study describes gun access and the “5 Ls” among US older adults. Methods. Data on the “5 Ls” from the Second Injury Control and Risk Survey (ICARIS-2, a national telephone survey conducted by the Centers for Disease Control and Prevention, were analyzed. Weighted variables were used to generate national estimates regarding prevalence of gun ownership and associated gun safety among older adults (≥55 years. Results. Of 2939 older adults, 39% (95% CI 37%–42% reported ≥1 gun stored at home. Among those with guns at home, 21% (95% CI 18–24% stored guns loaded and unlocked; 9.2% (95% CI 6.6–12% had ≥1 child in household; 5.1% (95% CI 3.5–6.8% reported past-year suicidal ideation and 3.6% (95% CI 2.1–5.2% reported history of a suicide attempt; and 55% (95% CI 51–59% stated that ≥1 adult had attended firearm safety workshop. Conclusion. Some older adults may be at elevated risk of firearm injury because of storage practices, suicidal thoughts, or limited safety training. Future work should assess effective approaches to reduce the risk of gun-related injuries among older adults.

  6. Gun Access and Safety Practices among Older Adults.

    Science.gov (United States)

    Lum, Hillary D; Flaten, Hanna K; Betz, Marian E

    2016-01-01

    Background. Given high rates of gun ownership among older adults, geriatric providers can assess firearm safety practices using a "5 Ls" approach: Locked; Loaded; Little children; feeling Low; and Learned owner. This study describes gun access and the "5 Ls" among US older adults. Methods. Data on the "5 Ls" from the Second Injury Control and Risk Survey (ICARIS-2), a national telephone survey conducted by the Centers for Disease Control and Prevention, were analyzed. Weighted variables were used to generate national estimates regarding prevalence of gun ownership and associated gun safety among older adults (≥55 years). Results. Of 2939 older adults, 39% (95% CI 37%-42%) reported ≥1 gun stored at home. Among those with guns at home, 21% (95% CI 18-24%) stored guns loaded and unlocked; 9.2% (95% CI 6.6-12%) had ≥1 child in household; 5.1% (95% CI 3.5-6.8%) reported past-year suicidal ideation and 3.6% (95% CI 2.1-5.2%) reported history of a suicide attempt; and 55% (95% CI 51-59%) stated that ≥1 adult had attended firearm safety workshop. Conclusion. Some older adults may be at elevated risk of firearm injury because of storage practices, suicidal thoughts, or limited safety training. Future work should assess effective approaches to reduce the risk of gun-related injuries among older adults. PMID:26949391

  7. The gun control system of the IFUSP microtron

    International Nuclear Information System (INIS)

    A thermionic gun control system has been developed for the IFUSP microtron. The control system, which is composed of a dedicated microcomputer, A/D converter, grid pulser, filament and grid power supplies, is kept at a high voltage potential. The gun parameters are handled through a PC computer at ground potential via fiber-optic link. (orig.)

  8. Everyday Engineering: What Makes a Squirt Gun Squirt?

    Science.gov (United States)

    Moyer, Richard; Everett, Susan

    2009-01-01

    You may not think of engineering and squirt guns in the same sentence. However, like many examples of engineering design, the squirt gun pump mechanism is uncomplicated, yet elegant, and very inexpensive to manufacture. The design is widely used because of its simplicity and low cost. With only a few moving parts, it is able to deliver a stream of…

  9. Taking Aim at Gun Violence: Rebuilding Community Education & Employment Pathways

    Science.gov (United States)

    Bryant, Rhonda

    2013-01-01

    In January 2013, President Obama released a plan for protecting children and communities by reducing gun violence. This plan has generated serious debate from both sides of the issue. The ensuing conversations about how to solve the issue of gun violence have been volatile. The President's plan includes reforms to close loopholes on background…

  10. What we know about gun use among adolescents.

    Science.gov (United States)

    Wilkinson, D L; Fagan, J

    2001-06-01

    The current generation of American teenagers has grown up surrounded by gun violence. Guns have played a significant role in shaping the developmental trajectories and behaviors of many inner-city youths. In this essay, we examine the role of guns in the lives of young people, and especially in the social and symbolic construction of violent events among adolescents, primarily focusing on males. First, we review studies of gun attitudes and behaviors as well as several epidemiological studies of firearm experiences and risk factors for violence among youth. Second, we summarize several recent studies on the trends in youth violence in relation to firearms. Next, we review findings from our original research based on in-depth interviews with 377 active gun offenders from two socially isolated inner-city neighborhoods. We present descriptive counts for the sample on variables relating to gun acquisition and use. Data on the use of guns in violent events among adolescents are generally lacking in prior research. We attempt to fill that knowledge gap by presenting a summary of our more detailed analysis of gun and nongun use in violent events reported by our respondents. PMID:11771792

  11. The breakdown phase in a coaxial plasma gun

    International Nuclear Information System (INIS)

    The electrical breakdown in a coaxial plasma gun was investigated by means of optical and electrical measurements. The optimum start and operation conditions of the gun turned out to be strongly dependent on material and length of the cylindrical insulator. (orig.)

  12. Gun Possession among Massachusetts Batterer Intervention Program Enrollees

    Science.gov (United States)

    Rothman, Emily F.; Johnson, Renee M.; Hemenway, David

    2006-01-01

    Batterers with access to firearms present a serious lethal threat to their partners. The purpose of this exploratory study is to estimate the prevalence of and risk markers for gun possession among Massachusetts men enrolled in batterer intervention programs. The authors found that 1.8% of the men reported having a gun in or around their home.…

  13. NASCAP simulation of laboratory charging tests using multiple electron guns

    Science.gov (United States)

    Mandell, M. J.; Katz, I.; Parks, D. E.

    1981-01-01

    NASCAP calculations have been performed simulating exposure of a spacecraft-like model to multiple electron guns. The results agree well with experiment. It is found that magnetic field effects are fairly small, but substantial differential charging can result from electron gun placement. Conditions for surface flashover are readily achieved.

  14. Gun Access and Safety Practices among Older Adults

    Science.gov (United States)

    Lum, Hillary D.; Flaten, Hanna K.; Betz, Marian E.

    2016-01-01

    Background. Given high rates of gun ownership among older adults, geriatric providers can assess firearm safety practices using a “5 Ls” approach: Locked; Loaded; Little children; feeling Low; and Learned owner. This study describes gun access and the “5 Ls” among US older adults. Methods. Data on the “5 Ls” from the Second Injury Control and Risk Survey (ICARIS-2), a national telephone survey conducted by the Centers for Disease Control and Prevention, were analyzed. Weighted variables were used to generate national estimates regarding prevalence of gun ownership and associated gun safety among older adults (≥55 years). Results. Of 2939 older adults, 39% (95% CI 37%–42%) reported ≥1 gun stored at home. Among those with guns at home, 21% (95% CI 18–24%) stored guns loaded and unlocked; 9.2% (95% CI 6.6–12%) had ≥1 child in household; 5.1% (95% CI 3.5–6.8%) reported past-year suicidal ideation and 3.6% (95% CI 2.1–5.2%) reported history of a suicide attempt; and 55% (95% CI 51–59%) stated that ≥1 adult had attended firearm safety workshop. Conclusion. Some older adults may be at elevated risk of firearm injury because of storage practices, suicidal thoughts, or limited safety training. Future work should assess effective approaches to reduce the risk of gun-related injuries among older adults. PMID:26949391

  15. Gunning Mix or Converter and Electric Arc Furnace in China

    Institute of Scientific and Technical Information of China (English)

    LIUJie-hua; ZHANGYong-fang

    1996-01-01

    The increase of steel output by converter and electric are furnace has imposed a critical demand in quality and quantity on gunning mix in functioning a longer life of those de-vices linings.The paoer describes the consump-tion of gunning mix for converter and EAF and its recent development in variety and quality in China.

  16. Normative Considerations in the Aftermath of Gun Violence in Schools

    Science.gov (United States)

    Gereluk, Dianne T.; Donlevy, J. Kent; Thompson, Merlin B.

    2015-01-01

    Gun violence in American and Canadian schools is an ongoing tragedy that goes substantially beyond its roots in the interlocking emotional and behavioral issues of mental health and bullying. In light of the need for effective policy development, Dianne T. Gereluk, J. Kent Donlevy, and Merlin B. Thompson examine gun violence in schools from…

  17. A Gridded Electron Gun for a Sheet Beam Klystron

    Energy Technology Data Exchange (ETDEWEB)

    Read, M.E.; Miram, G.; Ives, R.L.; /Calabazas Creek Res., Saratoga; Ivanov, V.; Krasnykh, A.; /SLAC

    2008-04-25

    This paper describes the development of an electron gun for a sheet beam klystron. Initially intended for accelerator applications, the gun can operate at a higher perveance than one with a cylindrically symmetric beam. Results of 2D and 3D simulations are discussed.

  18. Multikiloampere magnetron gun with secondary emission at relativistic voltage

    International Nuclear Information System (INIS)

    Magnetron gun for voltage up 1000 kV and current more 1 kA was tested in pulse mode. The secondary emission nature of the cathode current was established. The identification was held basing on considered features of the exciting and on the maintenance of the secondary emission current. The gun may be used for charge particle accelerators and RF power sources

  19. Plasma wave observations during electron gun experiments on ISEE-1

    OpenAIRE

    Olsen, R. C.; F. S. Mozer; Anderson, R. R.

    1992-01-01

    Advances in Space Research, 12, (12)29 The ISEE-1 electron guns were operated during the final orbits of ISEE-1 in 1987 in tests designed to study the stimulation of plasma waves. The guns were operated in modes which varied from ...

  20. Preventing Clogging In A Vacuum Plasma Spray Gun

    Science.gov (United States)

    Krotz, Phillip D.; Daniel, Ronald L., Jr.; Davis, William M.

    1994-01-01

    Modification of powder-injection ports enables lengthy, high-temperature deposition operations. Graphite inserts prevent clogging of ports through which copper powder injected into vacuum plasma spray (VPS) gun. Graphite liners eliminate need to spend production time refurbishing VPS gun, reducing cost of production and increasing productivity. Concept also applied to other material systems used for net-shape fabrication via VPS.

  1. Guns and Fear: A One-Way Street?

    Science.gov (United States)

    Hauser, Will; Kleck, Gary

    2013-01-01

    Surveys show that more than one half of gun owners report owning their firearm for self-protection. Although research has examined the effect of fear of crime on gun ownership, the issue of reciprocity and temporal order has been largely ignored. Furthermore, the effect of firearm acquisition and relinquishment on fear has not been evaluated…

  2. Modelling multi-ion plasma gun simulations of Tokamak disruptions

    International Nuclear Information System (INIS)

    The effect of impurity ions in plasma gun ablation tests of various targets is considered. Inclusion of reasonable amounts of impurity (∼10%) is adequate to explain observed energy transmission and erosion measurements. The gun tests and the computer code calculations are relevant to the parameter range expected for major disruptions on large tokamaks

  3. A 3 GHz photoelectron gun for high beam intensity

    CERN Document Server

    Bossart, Rudolf; Dehler, M; Godot, J C

    1996-01-01

    For the Compact Linear Collider Test Facility (CTF) at CERN a new rf gun with a laser driven photocathode is under construction. The new rf gun will replace the present 11/2 cell gun and will consist of 21/2 cells accelerating the beam to a momentum of 7.0 MeV/c with an electric field strength of 100 MV/m. The strong space-charge forces at low beam energy caused by the high charge density of the electron bunches are contained by radial and longitudinal rf focusing in the gun. The rf gun under construction has been optimized by MAFIA beam simulations for an injector assembly comprising a second accelerating rf structure and an intermediate solenoid magnet correcting the beam divergence of the 21/2 cell gun. The beam loading of the rf gun, by a train of 48 bunches with 21 nC charge each, causes a strong energy decay accompanied by an increase of the flight time for the bunches with lower energy. These effects can be corrected by slightly shifting the acceleration frequency of the gun. The experimental results...

  4. Rheology of cement grout  : Ultrasound based in-line measurement technique and grouting design parameters

    OpenAIRE

    Rahman, Mashuqur

    2015-01-01

    Grouting is performed in order to decrease the permeability and increase the stiffness of the material, especially soil and rock. For tunnelling and underground constructions, permeation grouting is done where cement based materials are pumped inside drilled boreholes under a constant pressure, higher than the ground water pressure. The aim of permeation grouting is to reduce the water flow into tunnels and caverns and to limit the lowering of the surrounding groundwater table. Cement based m...

  5. Prevention of clogging phenomenon with high-grouting pressure

    International Nuclear Information System (INIS)

    This paper describes a study on grouting strategy for crystalline rock. First, grouting practices used in Nordic countries are summarized. Their main characteristics are the usage of thick slurry of micro-cement, dense pattern of grout holes and simultaneous injection of plural holes, which enable both of high-level water sealing and shortening of grouting work. To investigate the applicability of thick cement slurry, high-pressure clogging test simulating real grouting work has been conducted. The test results indicated the possibility to prevent the clogging phenomenon of thick cement slurry, i.e. water cement ratio of 1.6, by increasing the injection pressure gradually. (author)

  6. Cement radwaste solidification studies third annual report

    International Nuclear Information System (INIS)

    This report summarises cement radwaste studies carried out at AEE Winfrith during 1981 on the encapsulation of medium and low active waste in cement. During the year more emphasis has been placed on the work which is directly related to the solidification of SGHWR active sludge. Information has been obtained on the properties of 220 dm3 drums of cemented waste. The use of cement grouts for the encapsulation of solid items has also been investigated during 1981. (U.K.)

  7. Cement Sheath Integrity During Thermal Cycling

    OpenAIRE

    Andrade, Jesús De

    2015-01-01

    In the construction process of oil and gas wells, primary cementing constitutes a critical procedure of placing a cement sheath in the annulus between casing and formation, or between the casing strings. The main purpose is to provide mechanical stability to the wellbore and to ensure zonal isolation through the entire well service lifetime. Failures to achieve a proper primary cementing, and to ensure long-term sealing capabilities of the cement sheath, may severely limit the abi...

  8. Micro Mechanics and Microstructures of Major Subsurface Hydraulic Barriers: Shale Caprock vs Wellbore Cement

    Science.gov (United States)

    Radonjic, M.; Du, H.

    2015-12-01

    Shale caprocks and wellbore cements are two of the most common subsurface impermeable barriers in the oil and gas industry. More than 60% of effective seals for geologic hydrocarbon bearing formations as natural hydraulic barriers constitute of shale rocks. Wellbore cements provide zonal isolation as an engineered hydraulic barrier to ensure controlled fluid flow from the reservoir to the production facilities. Shale caprocks were deposited and formed by squeezing excess formation water and mineralogical transformations at different temperatures and pressures. In a similar process, wellbore cements are subjected to compression during expandable tubular operations, which lead to a rapid pore water propagation and secondary mineral precipitation within the cement. The focus of this research was to investigate the effect of wellbore cement compression on its microstructure and mechanical properties, as well as a preliminary comparison of shale caprocks and hydrated cement. The purpose of comparative evaluation of engineered vs natural hydraulic barrier materials is to further improve wellbore cement durability when in contact with geofluids. The micro-indentation was utilized to evaluate the change in cement mechanical properties caused by compression. Indentation experiments showed an overall increase in hardness and Young's modulus of compressed cement. Furthermore, SEM imaging and Electron Probe Microanalysis showed mineralogical alterations and decrease in porosity. These can be correlated with the cement rehydration caused by microstructure changes as a result of compression. The mechanical properties were also quantitatively compared to shale caprock samples in order to investigate the similarities of hydraulic barrier features that could help to improve the subsurface application of cement in zonal isolation. The comparison results showed that the poro-mechanical characteristics of wellbore cement appear to be improved when inherent pore sizes are shifted to

  9. Long-term performance of the steel-cement interface in CO2 sequestration wells

    Science.gov (United States)

    Carey, J. W.; Han, J.

    2011-12-01

    Long-term performance of CO2 storage reservoirs will require that wells (injection, monitoring, and pre-existing) continue to provide isolation of the buoyant CO2 plume. Short-term leakage concerns are driven by the quality of the well completions, particularly placement of Portland cement. However, operational and CO2-injection induced stresses in the reservoir may introduce small defects in the well isolation system, allowing migration of small quantities of CO2 and brine. Evidence for such leaks has been observed in a CO2-enhanced oil recovery well (Carey et al. 2007) and in a natural CO2 reservoir (Crow et al. 2010). The key question in long-term performance is whether these leaks will grow as wellbore materials degrade or whether carbonate precipitation reactions will self-heal the defects. In this study, we focus on the interface between steel casing and Portland cement. In a properly completed well, Portland cement provides a protective, alkaline environment for carbon steel that precludes the possibility of external corrosion. The protective cement can be damaged either by the formation of small gaps at the interface, known as microannuli, or by the carbonation of cement which eliminates cement alkalinity. To investigate these issues, we conducted experiments on cement-steel composites at conditions ranging from atmospheric to high-pressure to determine the susceptibility of steel to corrosion in the presence of well-bonded cement, carbonated cement, and cement separated from the steel by varying gap distances. The presence of cement greatly reduces corrosion rates of steel because an iron carbonate scale forms rapidly and provides a mass-transfer barrier. Similarly, a small gap at the cement-steel interface provides a mass-transfer barrier. Our results show that scale formation provides a more significant barrier to corrosion and that even small gaps (oxide layer on steel is destroyed but then fall again as a carbonate scale forms. The degree of protection

  10. Neutron Scattering Studies of Cement

    Science.gov (United States)

    Allen, Andrew

    2010-03-01

    Despite more than a century of research, basic questions remain regarding both the internal structure and the role of water in Ordinary Portland cement (OPC) concrete, the world's most widely used manufactured material. Most such questions concern the primary hydration product and strength-building phase of OPC paste, the calcium silicate hydrate (C-S-H) gel. When cement and water are mixed, this phase precipitates as clusters of nanoscale (nearly amorphous) colloidal particles with an associated water-filled inter-particle pore system. Most attempts to characterize the C-S-H gel and the behavior of the associated water involve drying or other processes that, themselves, change the bound water content within and around the gel. Neutron scattering methods do not suffer from this disadvantage. Furthermore, the neutron isotope effect and the neutron's sensitivity to molecular motion have enabled considerable progress to be made in recent years by: (i) determining the C-S-H composition, density and gel structure in small-angle neutron scattering (SANS) H/D contrast variation studies; (ii) elucidating the changing state of water within cement as hydration progresses using quasielastic neutron scattering (QENS); and (iii) measuring the production and consumption of nanoscale calcium hydroxide (CH), a by-product of cement hydration that co-exists with the C-S-H gel, using inelastic neutron scattering (INS). These experiments have provided new insights into the physics and chemistry of cement hydration, and have implications for the design of new concretes with pozzolanic cement additions that are intended to address environmental concerns and sustainability issues.

  11. Guns, Mental Illness, and the Law: Introduction to This Issue.

    Science.gov (United States)

    Swanson, Jeffrey W; Felthous, Alan R

    2015-06-01

    Firearm violence is a top-tier public health problem in the U.S., killing 33,563 and injuring an additional 81,396 people in 2012 (Centers for Disease Control and Prevention, CDC, ). Given constitutional protection and the cultural entrenchment of private gun ownership in the U.S., it is likely that guns will remain widely accessible--and largely unrestricted--for the foreseeable future. Therefore, most policies and laws intended to reduce firearm violence focus selectively on preventing "dangerous people" from having access to guns. That is a formidable challenge. How do we think productively about guns and mental illness in this context, and about the role of law in lessening the toll of gun violence? PMID:25874748

  12. Polarized Electron Gun Development at the Brookhaven National Laboratory

    International Nuclear Information System (INIS)

    Development of two different polarized electron guns is ongoing at BNL. One aims at extremely high brightness at a moderate beam current. This design uses a superconducting RF gun and a test setup is built to show that a Gallium-Arsenide cathode with negative affinity has a sufficiently long quantum efficiency lifetime in such an environment. An electron injector using this technology may eliminate the need of the electron damping ring and a long transport line at the International Linear Collider. The other project aims at producing a high beam current with moderate emittance requirements, dubbed the 'Gatling gun'. In this DC gun, bunches are extracted from 20 separate cathodes and merged into a single beam using a rotating magnetic field. Such an electron gun could serve as an injector for the electron-ion collider eRHIC, which is planned at BNL. We will report on the status of these projects.

  13. Therminoic gun control system for the CEBAF injector

    International Nuclear Information System (INIS)

    The injector for the CEBAF accelerator must produce a high-quality electron beam to meet the overall accelerator specifications. A Hermosa electron gun with a 2 mm-diameter cathode and a control aperture has been chosen as the electron source. This must be controlled over a wide range of operating conditions to meet the beam specifications and to provide flexibility for accelerator commissioning. The gun is controlled using Computer Automated Measurement and Control (CAMAC IEEE-583) technology. The system employs the CAMAC-based control architecture developed at CEBAF. The control system has been tested, and early operating data on the electron gun and the injector beam transport system has been obtained. This system also allows gun parameters to be stored at the operator location, without paralyzing operation. This paper describes the use of this computer system in the control of the CEBAF electron gun. 2 refs., 6 figs., 1 tab

  14. ADVANCED CEMENTS FOR GEOTHERMAL WELLS

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    Using the conventional well cements consisting of the calcium silicate hydrates (CaO-SiO{sub 2}-H{sub 2}O system) and calcium aluminum silicate hydrates (CaO-Al{sub 2}O{sub 3}-SiO{sub 2}-H{sub 2}O system) for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanically supporting the metallic well casing pipes and in mitigating the pipe's corrosion in very harsh geothermal reservoirs. These difficulties are particularly acute in two geological regions: One is the deep hot downhole area ({approx} 1700 m depth at temperatures of {approx} 320 C) that contains hyper saline water with high concentrations of CO{sub 2} (> 40,000 ppm) in conjunction with {approx} 100 ppm H{sub 2}S at a mild acid of pH {approx} 5.0; the other is the upper well region between the well's surface and {approx} 1000 m depth at temperatures up to 200 C. The specific environment of the latter region is characterized by highly concentrated H{sub 2}SO{sub 4} (pH < 1.5) brine containing at least 5000 ppm CO{sub 2}. When these conventional cements are emplaced in these harsh environments, their major shortcoming is their susceptibility to reactions with hot CO{sub 2} and H{sub 2}SO4, thereby causing their deterioration brought about by CO{sub 2}-catalyzed carbonation and acid-initiated erosion. Such degradation not only reduced rapidly the strength of cements, lowering the mechanical support of casing pipes, but also increased the extent of permeability of the brine through the cement layer, promoting the rate of the pipe's corrosion. Severely carbonated and acid eroded cements often impaired the integrity of a well in less than one year; in the worst cases, casings have collapsed within three months, leading to the need for costly and time-consuming repairs or redrilling operations. These were the reasons why the geothermal well drilling and cementing industries were concerned about using conventional well

  15. Effects of variations in loading conditions on maximum pressure and muzzle velocity when using composite charge

    Directory of Open Access Journals (Sweden)

    V. B. Tawakley

    1960-10-01

    Full Text Available In this paper the effects on maximum pressure and muzzle velocity due to small changes in various quantities defining the loading conditions have been obtained mathematically when using composite charge in guns. Calculations have been done for a particular gun to illustrate these results.

  16. PERFORMANCE OF PULVERIZED SLAG-SUBSTITUTED CEMENT

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The Portland cement is equivalently substituted by slag micropowders with various specific areas. The workability,activity and acid-corrosion resistance of the slag-substituted cements are investigated,the activation of gypsum is discussed,also the porosity and pore distribution of mortars of the slag micropowders cement are determined by mercury intrusion porosimetry.

  17. Behavior-oriented approaches to reducing youth gun violence.

    Science.gov (United States)

    Hardy, Marjorie S

    2002-01-01

    Advocacy groups on both sides of the guns issue frequently point to changing personal behavior--of both parents and children--as a key element in reducing gun violence among youth. Efforts to bring about these changes range from community-based campaigns, to laws and programs that encourage parents to store their guns safely, to educational initiatives that focus on keeping young children away from guns and encouraging youth to resolve disputes without violence. Unfortunately, these behavior-oriented programs have not shown great success in reducing youth gun violence. This article reviews the research surrounding behavioral approaches to gun violence prevention and highlights obstacles that hamper the effectiveness of these programs. Supportive communities can play a key role in protecting youth from violence in general, but the few community-based violence prevention programs that focus on youth have not been shown to decrease youth access to or use of guns. By and large, behavioral programs and legal interventions aimed at parents have not been proven to reduce youth gun violence. This may be due in part to parental misperceptions about children's risk of injury and ability to protect themselves. Children and youth are particularly difficult targets for behavioral change programs. Cognitive immaturity among younger children and perceptions of invulnerability among adolescents may be part of the reason. Most programs that seek to persuade youth to stay away from guns have not been proven effective. The author concludes that, although behavioral programs could be improved, overall they hold only limited promise for reducing youth gun violence. PMID:12194605

  18. Microscale Investigation of Arsenic Distribution and Species in Cement Product from Cement Kiln Coprocessing Wastes

    OpenAIRE

    Yufei Yang; Jingchuan Xue; Qifei Huang

    2013-01-01

    To improve the understanding of the immobilization mechanism and the leaching risk of Arsenic (As) in the cement product from coprocessing wastes using cement kiln, distribution and species of As in cement product were determined by microscale investigation methods, including electron probe microanalysis (EPMA) and X-ray absorption spectroscopy. In this study, sodium arsenate crystals (Na3AsO412H2O) were mixed with cement production raw materials and calcined to produce cement clinker. Then, ...

  19. The comparison between sulfate salt weathering of portland cement paste and calcium sulfoaluminate cement paste

    OpenAIRE

    Liu, Zanqun; Deng, Dehua; De Schutter, Geert

    2015-01-01

    In this paper, the damage performances of sulfate salt weathering of Portland cement paste and calcium sulfoaluminate (CSA) cement paste were compared according to authors' previous studies. It was found that the evaporation zone of speciments partially immersed in 10% Na2SO4 solution were both severely deteriorated for Portland cement and CSA cement. However, the differences were more significant: (1) the CSA cement paste were damaged just after 7 days exposure compared to the 5 months expos...

  20. 77 FR 37834 - Revocation of Certain Requirements Pertaining to Caps Intended for Use With Toy Guns and Toy Guns...

    Science.gov (United States)

    2012-06-25

    ... CPSC. See 38 FR 27012 (September 27, 1973). One of the transferred regulations includes a ban on caps... COMMISSION 16 CFR Part 1500 Revocation of Certain Requirements Pertaining to Caps Intended for Use With Toy Guns and Toy Guns Not Intended for Use With Caps AGENCY: Consumer Product Safety Commission....