Science.gov

Sample records for reflecting projectile octupole

  1. Octupole degree of freedom for the critical-point candidate nucleus {sup 152}Sm in a reflection-asymmetric relativistic mean-field approach

    SciTech Connect

    Zhang, W.; Li, Z. P.; Zhang, S. Q.; Meng, J.

    2010-03-15

    The potential energy surfaces of even-even {sup 146-156}Sm are investigated in the constrained reflection-asymmetric relativistic mean-field approach with parameter set PK1. It is shown that the critical-point candidate nucleus {sup 152}Sm marks the shape/phase transition not only from U(5) to SU(3) symmetry, but also from the octupole-deformed ground state in {sup 150}Sm to the quadrupole-deformed ground state in {sup 154}Sm. By including the octupole degree of freedom, an energy gap near the Fermi surface for single-particle levels in {sup 152}Sm with beta{sub 2}=0.14approx0.26 is found and the important role of the octupole deformation driving pair nu2f{sub 7/2} and nu1i{sub 13/2} is demonstrated.

  2. Multiple octupole-type band structures in {sup 220}Th: Reflection-asymmetric tidal waves?

    SciTech Connect

    Reviol, W.; Chiara, C. J.; Montero, M.; Sarantites, D. G.; Pechenaya, O. L.; Carpenter, M. P.; Janssens, R. V. F.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Seweryniak, D.; Zhu, S.; Frauendorf, S. G.

    2006-10-15

    The {sup 220}Th level scheme has been considerably extended from an experiment using the {sup 26}Mg+{sup 198}Pt reaction at 128 MeV. The evaporation residues from this very fissile system were selected with the HERCULES detector system and residue-gated {gamma} rays were measured with Gammasphere. The simplex feature (alternating-parity levels) persists up to the highest spins observed (23({Dirac_h}/2{pi})), but the nucleus exhibits a more vibrational-like behavior than the heavier Th isotopes. In addition, a doubling of the negative-parity, odd-spin states is seen as well as a staggering of the B(E1)/B(E2) ratios. A new interpretation based on a picture of tidal waves on a reflection-asymmetric nuclear surface is proposed.

  3. Octupole collectivity in nuclei

    NASA Astrophysics Data System (ADS)

    Butler, P. A.

    2016-07-01

    The experimental and theoretical evidence for octupole collectivity in nuclei is reviewed. Recent theoretical advances, covering a wide spectrum from mean-field theory to algebraic and cluster approaches, are discussed. The status of experimental data on the behaviour of energy levels and electric dipole and electric octupole transition moments is reviewed. Finally, an outlook is given on future prospects for this field.

  4. Nonaxial-octupole effect in superheavy nuclei

    SciTech Connect

    Chen, Y.-S.; Sun, Yang; Gao Zaochun

    2008-06-15

    The triaxial-octupole Y{sub 32} correlation in atomic nuclei has long been expected to exist but experimental evidence has not been clear. We find, in order to explain the very low-lying 2{sup -} bands in the transfermium mass region, that this exotic effect may manifest itself in superheavy elements. Favorable conditions for producing triaxial-octupole correlations are shown to be present in the deformed single-particle spectrum, which is further supported by quantitative Reflection Asymmetric Shell Model calculations. It is predicted that the strong nonaxial-octupole effect may persist up to the element 108. Our result thus represents the first concrete example of spontaneous breaking of both axial and reflection symmetries in the heaviest nuclear systems.

  5. Comment on {open_quotes}Experimental Fusion Barrier Distributions Reflecting Projectile Octupole State Coupling to Prolate and Oblate Target Nuclei{close_quotes}

    SciTech Connect

    Dasso, C.H.; Dasso, C.H.; Fernandez-Niello, J.

    1997-05-01

    The authors comment on the Letter by J.D. Bierman et al., Phys. Rev. Lett. 76, 1587(1996), and show the method by which they have been constructed is not the most appropriate. A Comment on the Letter by J.D. Bierman, {ital et al. }, Phys.Rev.Lett.{bold 76}, 1587 (1996). The authors of the Letter offer a Reply. {copyright} {ital 1997} {ital The American Physical Society}

  6. Octupole shapes in heavy nuclei

    SciTech Connect

    Ahmad, I.

    1994-08-01

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets.

  7. Octupole correlation effects in nuclei

    SciTech Connect

    Chasman, R.R.

    1992-08-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

  8. Octupole correlation effects in nuclei

    SciTech Connect

    Chasman, R.R.

    1992-01-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

  9. Projectile stopping system

    DOEpatents

    Karr, T.J.; Pittenger, L.C.

    1996-11-26

    A projectile interceptor launches a projectile catcher into the path of a projectile. In one embodiment, signals indicative of the path of a projectile are received by the projectile interceptor. A flinger mechanism has a projectile catcher releasably attached thereto, such that the projectile catcher can be released and launched from the flinger mechanism. A controller connected to the flinger mechanism uses the signals indicative of the path of the projectile to determine the launch parameters of the projectile catcher. The controller directs the flinger mechanism to release the projectile catcher such that the projectile catcher is launched into the path of the projectile and intercepts the projectile. 13 figs.

  10. Projectile stopping system

    DOEpatents

    Karr, Thomas J.; Pittenger, Lee C.

    1996-01-01

    A projectile interceptor launches a projectile catcher into the path of a projectile. In one embodiment, signals indicative of the path of a projectile are received by the projectile interceptor. A flinger mechanism has a projectile catcher releasably attached thereto, such that the projectile catcher can be released and launched from the flinger mechanism. A controller connected to the flinger mechanism uses the signals indicative of the path of the projectile to determine the launch parameters of the projectile catcher. The controller directs the flinger mechanism to release the projectile catcher such that the projectile catcher is launched into the path of the projectile and intercepts the projectile.

  11. Octupole correlations in the heavy elements

    SciTech Connect

    Chasman, R.R.

    1986-01-01

    The effects of octupole correlations on the nuclear structure of the heavy elements are discussed. The cluster model description of the heavy elements is analyzed. The relevance of 2/sup 6/-pole deformation and fast El transitions to an octupole model is considered. 30 refs., 21 figs., 1 tab.

  12. Modified octupoles for damping coherent instabilities

    SciTech Connect

    Cornacchia, M. . Stanford Synchrotron Radiation Lab.); Corbett, W.J. ); Halbach, K. )

    1991-05-01

    The introduction tune spread in circular e{sup +}e{sup {minus}} accelerators with modified octupoles to reduce the loss of dynamic aperture is discussed. The new magnet design features an octupole of field component on-axis and a tapered field structure off-axis to minimize loss of dynamic aperture. Tracking studies show that the modified octupoles can produce the desired tune spread in SPEAR without compromising confinement of the beam. The technique for designing such magnets is presented, together with an example of magnets that give the required field distribution. 7 refs., 7 figs.

  13. Octupole collectivity in 94Zr

    NASA Astrophysics Data System (ADS)

    Toh, Y.; Oshima, M.; Koizumi, M.; Osa, A.; Kimura, A.; Sugawara, M.; Goto, J.

    2009-01-01

    The Zr isotopes between 90Zr and 96Zr are expected to be spherical based on the almost complete subshell closures at Z = 40 and N = 50, 56. On the other hand, they have low-lying 3- states and show the characteristics of low frequency octupole oscillation which arise as a superposition of particle-hole excitations. A 380 MeV 94Zr beam from the tandem accelerator at the Japan Atomic Energy Agency (JAEA) was excited on a self-supporting natPb target. The gamma-ray detector array GEMINI-II was used to detect deexcitation gamma rays. The scattered beam (94Zr) was detected with a position-sensitive particle detector system. The gamma-ray intensities were used as an input to the least-squares search code GOSIA to determine the E3 matrix element of the first 3- excited state of 94Zr. The B(E3;0+→3-) value of 0.21(6) e2b3 in 94Zr has been obtained by Coulomb excitation experiment.

  14. Projectile Motion Details.

    ERIC Educational Resources Information Center

    Schnick, Jeffrey W.

    1994-01-01

    Presents an exercise that attempts to correct for the common discrepancies between theoretical and experimental predictions concerning projectile motion using a spring-loaded projectile ball launcher. Includes common correction factors for student use. (MVL)

  15. Superconducting Magnetic Projectile Launcher

    NASA Technical Reports Server (NTRS)

    Jan, Darrell L.; Lawson, Daniel D.

    1991-01-01

    Proposed projectile launcher exploits Meissner effect to transfer much of kinetic energy of relatively massive superconducting plunger to smaller projectile, accelerating projectile to high speed. Because it operates with magnetic fields, launcher not limited by gas-expansion thermodynamics. Plunger energized mechanically and/or chemically, avoiding need for large electrical power supplies and energy-storage systems. Potential applications include launching of projectiles for military purposes and for scientific and industrial tests of hypervelocity impacts.

  16. The EMET railgun projectile

    SciTech Connect

    Burton, R.L.; Witherspoon, F.D.; Goldstein, S.A. )

    1991-01-01

    This paper reports on the EMET projectile which uses joule heating to accelerate the projectile in a railgun with a predominantly electrothermal driving force. The structure is designed to conduct armature current within a thin annular band around the shank of the large L/D dumbbell-shaped projectile. Current is initiated by a fuse located around the shank, and an impedance of 8 m{Omega} is achieved, compared to the 1-2 m{Omega} observed for EM guns. A supersonic nozzle in the projectile tail section expands and cools the armature plasma to raise its resistivity, prevent secondary arcs and provide additional accelerating thrust. Experimental data is presented for 9.5 mm diameter, 5 gm projectiles, accelerated to nearly 600 m/sec at 55 kA in a 0.9 m railgun. The armature remains confined in the projectile structure, and 75% of the acceleration is provided electrothermally.

  17. Evolution of octupole correlations in 123Ba

    NASA Astrophysics Data System (ADS)

    Chen, X. C.; Zhao, J.; Xu, C.; Hua, H.; Shneidman, T. M.; Zhou, S. G.; Wu, X. G.; Li, X. Q.; Zhang, S. Q.; Li, Z. H.; Liang, W. Y.; Meng, J.; Xu, F. R.; Qi, B.; Ye, Y. L.; Jiang, D. X.; Cheng, Y. Y.; He, C.; Sun, J. J.; Han, R.; Niu, C. Y.; Li, C. G.; Li, P. J.; Wang, C. G.; Wu, H. Y.; Li, Z. H.; Zhou, H.; Hu, S. P.; Zhang, H. Q.; Li, G. S.; He, C. Y.; Zheng, Y.; Li, C. B.; Li, H. W.; Wu, Y. H.; Luo, P. W.; Zhong, J.

    2016-08-01

    High-spin states of 123Ba have been studied via the 108Cd(19F,3 n p )123Ba fusion-evaporation reaction at a beam energy of 90 MeV. Several E 1 transitions linking the positive-parity ν (d5 /2+g7 /2) band and negative-parity ν h11 /2 band are observed in 123Ba for the first time. Evidence for the existence of octupole correlations in 123Ba is presented based on the systematic comparisons of the B (E 1 )/B (E 2 ) branching ratios and the energy displacements in odd-A Ba isotopes. The characteristics of octupole correlation in the odd-A Ba,125123 are explained by the state-of-the-art multidimensionally-constrained relativistic mean-field model and cluster model based on the dinuclear system concept.

  18. Hybrid armature projectile

    DOEpatents

    Hawke, R.S.; Asay, J.R.; Hall, C.A.; Konrad, C.H.; Sauve, G.L.; Shahinpoor, M.; Susoeff, A.R.

    1993-03-02

    A projectile for a railgun that uses a hybrid armature and provides a seed block around part of the outer surface of the projectile to seed the hybrid plasma brush. In addition, the hybrid armature is continuously vaporized to replenish plasma in a plasma armature to provide a tandem armature and provides a unique ridge and groove to reduce plasma blowby.

  19. Hybrid armature projectile

    DOEpatents

    Hawke, Ronald S.; Asay, James R.; Hall, Clint A.; Konrad, Carl H.; Sauve, Gerald L.; Shahinpoor, Mohsen; Susoeff, Allan R.

    1993-01-01

    A projectile for a railgun that uses a hybrid armature and provides a seed block around part of the outer surface of the projectile to seed the hybrid plasma brush. In addition, the hybrid armature is continuously vaporized to replenish plasma in a plasma armature to provide a tandem armature and provides a unique ridge and groove to reduce plasama blowby.

  20. Projectile Motion Revisited.

    ERIC Educational Resources Information Center

    Lucie, Pierre

    1979-01-01

    Analyzes projectile motion using symmetry and simple geometry. Deduces the direction of velocity at any point, range, time of flight, maximum height, safety parabola, and maximum range for a projectile launched upon a plane inclined at any angle with respect to the horizontal. (Author/GA)

  1. Teaching Projectile Motion

    ERIC Educational Resources Information Center

    Summers, M. K.

    1977-01-01

    Described is a novel approach to the teaching of projectile motion of sixth form level. Students are asked to use an analogue circuit to observe projectile motion and to graph the experimental results. Using knowledge of basic dynamics, students are asked to explain the shape of the curves theoretically. (Author/MA)

  2. A Projectile Motion Bullseye.

    ERIC Educational Resources Information Center

    Lamb, William G.

    1985-01-01

    Explains a projectile motion experiment involving a bow and arrow. Procedures to measure "muzzle" velocity, bow elastic potential energy, range, flight time, wind resistance, and masses are considered. (DH)

  3. Small caliber guided projectile

    DOEpatents

    Jones, James F.; Kast, Brian A.; Kniskern, Marc W.; Rose, Scott E.; Rohrer, Brandon R.; Woods, James W.; Greene, Ronald W.

    2010-08-24

    A non-spinning projectile that is self-guided to a laser designated target and is configured to be fired from a small caliber smooth bore gun barrel has an optical sensor mounted in the nose of the projectile, a counterbalancing mass portion near the fore end of the projectile and a hollow tapered body mounted aft of the counterbalancing mass. Stabilizing strakes are mounted to and extend outward from the tapered body with control fins located at the aft end of the strakes. Guidance and control electronics and electromagnetic actuators for operating the control fins are located within the tapered body section. Output from the optical sensor is processed by the guidance and control electronics to produce command signals for the electromagnetic actuators. A guidance control algorithm incorporating non-proportional, "bang-bang" control is used to steer the projectile to the target.

  4. Hypervelocity projectile design and fabrication

    SciTech Connect

    Ang, J.A.; Konrad, C.H.; Hall, C.A.; Susoeff, A.R.; Hawke, R.S.; Sauve, G.L.; Vasey, A.R.; Gosling, S.M.; Hickman, R.J.

    1990-12-31

    The projectile is the easiest element of a railgun system to modify. The projectile design can also play a major role in the successful operation of a railgun. This paper presents the design and fabrication techniques that have been used to increase the strength of the projectiles used in the STARFIRE Project. In addition, various diagnostics that have been used to guide our projectile development and monitor projectile integrity are reviewed. 10 refs.

  5. Octupole and hexadecapole bands in 152Sm

    SciTech Connect

    Garrett, P E; Kulp, W D; Wood, J L; Bandyopadhyay, D; Christen, S; Choudry, S; Dewald, A; Fitzler, A; Fransen, C; Jessen, K; Jolie, J; Kloezer, A; Kudejova, P; Kumar, A; Lesher, S R; Linnemann, A; Lisetskiy, A; Martin, D; Masur, M; McEllistrem, M T; Moller, O; Mynk, M; Orce, J N; Pejovic, P; Pissulla, T; Regis, J; Schiller, A; Tonev, D; Yates, S W

    2005-05-13

    The nucleus {sup 152}Sm is characterized by a variety of low-energy collective modes, conventionally described as rotations, {beta} vibrations, and {gamma} vibrations. Recently, it has been suggested that {sup 152}Sm is at a critical point between spherical and deformed collective phases. Consequently, {sup 152}Sm is being studied by a variety of techniques, including radioactive decay, multi-step Coulomb excitation, in-beam ({alpha},2n{gamma}) {gamma}-ray spectroscopy, and (n,n'{gamma}) spectroscopy. The present work focuses on the latter two reactions; these have been used to investigate the low-lying bands associated with the octupole degree of freedom, including one built on the first excited 0{sup +} band. In addition, the K{sup {pi}} = 4{sup +} hexadecapole vibrational band has been identified.

  6. Evidence for Octupole Correlations in Multiple Chiral Doublet Bands

    NASA Astrophysics Data System (ADS)

    Liu, C.; Wang, S. Y.; Bark, R. A.; Zhang, S. Q.; Meng, J.; Qi, B.; Jones, P.; Wyngaardt, S. M.; Zhao, J.; Xu, C.; Zhou, S.-G.; Wang, S.; Sun, D. P.; Liu, L.; Li, Z. Q.; Zhang, N. B.; Jia, H.; Li, X. Q.; Hua, H.; Chen, Q. B.; Xiao, Z. G.; Li, H. J.; Zhu, L. H.; Bucher, T. D.; Dinoko, T.; Easton, J.; Juhász, K.; Kamblawe, A.; Khaleel, E.; Khumalo, N.; Lawrie, E. A.; Lawrie, J. J.; Majola, S. N. T.; Mullins, S. M.; Murray, S.; Ndayishimye, J.; Negi, D.; Noncolela, S. P.; Ntshangase, S. S.; Nyakó, B. M.; Orce, J. N.; Papka, P.; Sharpey-Schafer, J. F.; Shirinda, O.; Sithole, P.; Stankiewicz, M. A.; Wiedeking, M.

    2016-03-01

    Two pairs of positive-and negative-parity doublet bands together with eight strong electric dipole transitions linking their yrast positive- and negative-parity bands have been identified in 78Br. They are interpreted as multiple chiral doublet bands with octupole correlations, which is supported by the microscopic multidimensionally-constrained covariant density functional theory and triaxial particle rotor model calculations. This observation reports the first example of chiral geometry in octupole soft nuclei.

  7. Chaos in axially symmetric potentials with octupole deformation

    SciTech Connect

    Heiss, W.D.; Nazmitdinov, R.G.; Radu, S. Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, E-28049, Madrid )

    1994-04-11

    Classical and quantum mechanical results are reported for the single particle motion in a harmonic oscillator potential which is characterized by a quadrupole deformation and an additional octupole deformation. The chaotic character of the motion is strongly dependent on the quadrupole deformation in that for a prolate deformation virtually no chaos is discernible while for the oblate case the motion shows strong chaos when the octupole term is turned on.

  8. Evidence for Octupole Correlations in Multiple Chiral Doublet Bands.

    PubMed

    Liu, C; Wang, S Y; Bark, R A; Zhang, S Q; Meng, J; Qi, B; Jones, P; Wyngaardt, S M; Zhao, J; Xu, C; Zhou, S-G; Wang, S; Sun, D P; Liu, L; Li, Z Q; Zhang, N B; Jia, H; Li, X Q; Hua, H; Chen, Q B; Xiao, Z G; Li, H J; Zhu, L H; Bucher, T D; Dinoko, T; Easton, J; Juhász, K; Kamblawe, A; Khaleel, E; Khumalo, N; Lawrie, E A; Lawrie, J J; Majola, S N T; Mullins, S M; Murray, S; Ndayishimye, J; Negi, D; Noncolela, S P; Ntshangase, S S; Nyakó, B M; Orce, J N; Papka, P; Sharpey-Schafer, J F; Shirinda, O; Sithole, P; Stankiewicz, M A; Wiedeking, M

    2016-03-18

    Two pairs of positive-and negative-parity doublet bands together with eight strong electric dipole transitions linking their yrast positive- and negative-parity bands have been identified in ^{78}Br. They are interpreted as multiple chiral doublet bands with octupole correlations, which is supported by the microscopic multidimensionally-constrained covariant density functional theory and triaxial particle rotor model calculations. This observation reports the first example of chiral geometry in octupole soft nuclei. PMID:27035296

  9. More on Projectile Motion.

    ERIC Educational Resources Information Center

    Molina, M. I.

    2000-01-01

    Mathematically explains why the range of a projectile is most insensitive to aiming errors when the initial angle is close to 45 degrees, whereas other observables such as maximum height or flight time are most insensitive for near-vertical launching conditions. (WRM)

  10. Projectiles and Aerodynamic Forces.

    ERIC Educational Resources Information Center

    Armstrong, H. L.

    1984-01-01

    Discusses the air resistance on projectiles, examining (in separate sections) air resistance less than gravity and air resistance greater than gravity. Also considers an approximation in which a trajectory is divided into two parts, the first part neglecting gravity and the second part neglecting the air resistance. (JN)

  11. Octupole shaps in nuclei, and some rotational consequences thereof

    SciTech Connect

    Nazarewicz, W.; Olanders, P.; Ragnarsson, I.; Dudek, J.; Leander, G.A.

    1984-01-01

    During the last years a large number of experimental papers presenting spectroscopic evidence for collective dipole and octupole deformations have appeared. Many theoretical attempts have been made to explain the observed spectroscopic properties in terms of stable octupole deformations. The coupling by the octupole potential, being proportional to Y/sub 30/, is strongest for those subshells for which ..delta..1 = 3. Therefore the tendency towards octupole deformation occurs just beyond closed shells where the high-j intruder subshells (N,1,j) lie very close to the normal parity subshells (N-1,1-3,j-3), i.e. for the particle numbers 34 (g/sub 9/2/-p/sub 3/2/), 56 (h/sub 11/2/-d/sub 5/2/). 9C (i/sub 13/2/-f/sub 7/2/) and 134 (j/sub 15/2/-g/sub 9/2/). Empirically, it is specifically for the particle numbers listed above that negative parity states are observed at relatively low energies in doubly even nuclei. From the different combinations of octupole-driving particle numbers four regions of likely candidates for octupole deformed equilibrium shapes emerge, namely the neutron-deficient nuclei with Z approx. = 90, N approx. = 134 (light actinides) and Z approx. = 34, N approx. = 34 (A approx. = 70) and the neutron-rich nuclei with Z approx. = 56, N approx. = 90 (heavy Ba) and Z approx. = 34, N/sup 56/ (A approx. = 90). In our calculations we searched for octupole unstable nuclei in these four mass regions. The Strutinsky method with the deformed Woods-Saxon potential was employed. The macroscopic part consists of a finite-range liquid drop energy, where both the surface and Coulomb terms contain a diffuseness correction.

  12. Search for octupole correlations in 147Nd

    NASA Astrophysics Data System (ADS)

    Ruchowska, E.; Mach, H.; Kowal, M.; Skalski, J.; Płóciennik, W. A.; Fogelberg, B.

    2015-09-01

    Properties of excited states in 147Nd have been studied with the multispectra and γ γ coincidence measurements. Twenty-four new γ lines and three new levels have been introduced into the level scheme of 147Nd. Using the advanced time-delayed β γ γ (t ) method, we measured lifetimes of eight excited levels in 147Nd, populated via the β decay of 147Pr. We have determined reduced transition probabilities for 30 γ transitions. Multidimensional potential energy surface calculations performed for 147Nd suggest two single-quasiparticle configurations with nonzero octupole deformation, with K =1 /2 and K =5 /2 . Our calculations also predict a sizable value of the electric dipole moment | D0|=0.26 e fm for this nucleus, while experimentally, a lower limit of | D0|≥0.02 e fm has been evaluated for the supposed K =1 /2 parity doublet. In contrast to the theoretical results, we do not observe the parity doublet bands with K =5 /2 . This, and the lack of theoretically expected E 1 strength in Nd,149147 may signal some poorly understood structural effect in the odd-N lanthanides.

  13. Subcaliber discarding sabot airgun projectiles.

    PubMed

    Frank, Matthias; Schönekeß, Holger; Herbst, Jörg; Staats, Hans-Georg; Ekkernkamp, Axel; Nguyen, Thanh Tien; Bockholdt, Britta

    2014-03-01

    Medical literature abounds with reports on injuries and fatalities caused by airgun projectiles. While round balls or diabolo pellets have been the standard projectiles for airguns for decades, today, there are a large number of different airgun projectiles available. A very uncommon--and until now unique--discarding sabot airgun projectile (Sussex Sabo Bullet) was introduced into the market in the 1980s. The projectile, available in 0.177 (4.5 mm) and 0.22 (5.5 mm) caliber, consists of a plastic sabot cup surrounding a subcaliber copper-coated lead projectile in typical bullet shape. Following the typical principle of a discarding sabot projectile, the lightweight sabot is supposed to quickly loose velocity and to fall to the ground downrange while the bullet continues on target. These sabot-loaded projectiles are of special forensic interest due to their non-traceability and ballistic parameters. Therefore, it is the aim of this work to investigate the ballistic performance of these sabot airgun projectiles by high-speed video analyses and by measurement of the kinetic parameters of the projectile parts by a transient recording system as well as observing their physical features after being fired. While the sabot principle worked properly in high-energy airguns (E > 17 J), separation of the core projectile from the sabot cup was also observed when discharged in low-energy airguns (E < 7.5 J). While the velocity of the discarded Sussex Sabo core projectile was very close to the velocity of a diabolo-type reference projectile (RWS Meisterkugel), energy density was up to 60 % higher. To conclude, this work is the first study to demonstrate the regular function of this uncommon type of airgun projectile. PMID:24263305

  14. Skirted projectiles for railguns

    DOEpatents

    Hawke, R.S.; Susoeff, A.R.

    1994-01-04

    A single skirt projectile (20) having an insulating skirt (22) at its rear, or a dual trailing skirt projectile (30, 40, 50, 60) having an insulating skirt (32, 42, 52, 62) succeeded by an arc extinguishing skirt (34, 44, 54, 64), is accelerated by a railgun accelerator 10 having a pair of parallel conducting rails (1a, 1b) which are separated by insulating wall spacers (11). The insulating skirt (22, 32, 42, 52, 62) includes a plasma channel (38). The arc extinguishing skirt (34, 44, 54, 64) interrupts the conduction that occurs in the insulating skirt channel (38) by blocking the plasma arc (3) from conducting current from rail to rail (1a, 1b) at the rear of the projectile (30, 40, 50, 60). The arc extinguishing skirt may be comprised of two plates (36a, 36b) which form a horseshoe wherein the plates are parallel to the rails (1a, b); a chisel-shape design; cross-shaped, or it may be a cylindrical (64). The length of the insulating skirt channel is selected such that there is sufficient plasma in the channel to enable adequate current conduction between the rails (1a, 1b).

  15. Skirted projectiles for railguns

    DOEpatents

    Hawke, Ronald S.; Susoeff, Allan R.

    1994-01-01

    A single skirt projectile (20) having an insulating skirt (22) at its rear, or a dual trailing skirt projectile (30, 40, 50, 60) having an insulating skirt (32, 42, 52, 62) succeeded by an arc extinguishing skirt (34, 44, 54, 64), is accelerated by a railgun accelerator 10 having a pair of parallel conducting rails (1a, 1b) which are separated by insulating wall spacers (11). The insulating skirt (22, 32, 42, 52, 62) includes a plasma channel (38). The arc extinguishing skirt (34, 44, 54, 64) interrupts the conduction that occurs in the insulating skirt channel (38) by blocking the plasma arc (3) from conducting current from rail to rail (1a, 1b) at the rear of the projectile (30, 40, 50, 60). The arc extinguishing skirt may be comprised of two plates (36a, 36b) which form a horseshoe wherein the plates are parallel to the rails (1a, b); a chisel-shape design; cross-shaped, or it may be a cylindrical (64). The length of the insulating skirt channel is selected such that there is sufficient plasma in the channel to enable adequate current conduction between the rails (1a, 1b).

  16. Periodic orbits and shell structure in octupole deformed potentials

    SciTech Connect

    Heiss, W.D. ); Nazmitdinov, R.G. ); Radu, S. )

    1995-01-15

    The effect of an octupole term in a quadrupole deformed single-particle potential is studied from the classical and quantum-mechanical viewpoint. Whereas the problem is nonintegrable, the quantum-mechanical spectrum nevertheless shows some shell structure in the superdeformed prolate case for particular, yet fairly large octupole strengths; for spherical or oblate deformation the shell structure disappears. This result is associated with classical periodic orbits that are found by employing the removal of resonances method; this approximation method allows determination of the shape of the orbit and of the approximate octupole coupling strength for which it occurs. The validity of the method is confirmed by solving numerically the classical equations of motion. The quantum-mechanical shell structure is analyzed using the particle-number dependence of the fluctuating part of the total energy. In accordance with the classical result, this dependence turns out to be very similar for a superdeformed prolate potential plus octupole term and a hyperdeformed prolate potential without octupole term. In this way the shell structure is explained at least for some few hundred levels. The Fourier transform of the level density further corroborates these findings.

  17. Two-phonon octupole excitation in {sup 146}Gd

    SciTech Connect

    Caballero, L.; Rubio, B.; Nacher, E.; Kleinheinz, P.; Yates, S. W.; Algora, A.; Dewald, A.; Fitzler, A.; Jolie, J.; Linnemann, A.; Moeller, O.; Gadea, A.; Julin, R.; Piiparinen, M.; Lunardi, S.; Menegazzo, R.; Blomqvist, J.

    2010-03-15

    Based on experimental evidence from the {sup 144}Sm({alpha},2n) reaction, the 3484.7-keV 6{sup +} state in {sup 146}Gd is identified as the highest-spin member of the 3{sup -} x 3{sup -} two-phonon octupole quartet. A previously unknown {gamma} line of 1905.8 keV and E3 character feeding the 3{sup -} octupole state has been observed. These results represent the first observation of a 6{sup +}->3{sup -}->0{sup +} cascade of two E3 transitions in an even-even nucleus and provide strong support for the interpretation of the 6{sup +} state as a two-phonon octupole excitation.

  18. Octupole strength in the neutron-rich calcium isotopes

    NASA Astrophysics Data System (ADS)

    Riley, L. A.; McPherson, D. M.; Agiorgousis, M. L.; Baugher, T. R.; Bazin, D.; Bowry, M.; Cottle, P. D.; DeVone, F. G.; Gade, A.; Glowacki, M. T.; Gregory, S. D.; Haldeman, E. B.; Kemper, K. W.; Lunderberg, E.; Noji, S.; Recchia, F.; Sadler, B. V.; Scott, M.; Weisshaar, D.; Zegers, R. G. T.

    2016-04-01

    Low-lying excited states of the neutron-rich calcium isotopes Ca-5248 have been studied via γ -ray spectroscopy following inverse-kinematics proton scattering on a liquid hydrogen target using the GRETINA γ -ray tracking array. The energies and strengths of the octupole states in these isotopes are remarkably constant, indicating that these states are dominated by proton excitations.

  19. Ballistic projectile trajectory determining system

    DOEpatents

    Karr, T.J.

    1997-05-20

    A computer controlled system determines the three-dimensional trajectory of a ballistic projectile. To initialize the system, predictions of state parameters for a ballistic projectile are received at an estimator. The estimator uses the predictions of the state parameters to estimate first trajectory characteristics of the ballistic projectile. A single stationary monocular sensor then observes the actual first trajectory characteristics of the ballistic projectile. A comparator generates an error value related to the predicted state parameters by comparing the estimated first trajectory characteristics of the ballistic projectile with the observed first trajectory characteristics of the ballistic projectile. If the error value is equal to or greater than a selected limit, the predictions of the state parameters are adjusted. New estimates for the trajectory characteristics of the ballistic projectile are made and are then compared with actual observed trajectory characteristics. This process is repeated until the error value is less than the selected limit. Once the error value is less than the selected limit, a calculator calculates trajectory characteristics such a the origin and destination of the ballistic projectile. 8 figs.

  20. Ballistic projectile trajectory determining system

    DOEpatents

    Karr, Thomas J.

    1997-01-01

    A computer controlled system determines the three-dimensional trajectory of a ballistic projectile. To initialize the system, predictions of state parameters for a ballistic projectile are received at an estimator. The estimator uses the predictions of the state parameters to estimate first trajectory characteristics of the ballistic projectile. A single stationary monocular sensor then observes the actual first trajectory characteristics of the ballistic projectile. A comparator generates an error value related to the predicted state parameters by comparing the estimated first trajectory characteristics of the ballistic projectile with the observed first trajectory characteristics of the ballistic projectile. If the error value is equal to or greater than a selected limit, the predictions of the state parameters are adjusted. New estimates for the trajectory characteristics of the ballistic projectile are made and are then compared with actual observed trajectory characteristics. This process is repeated until the error value is less than the selected limit. Once the error value is less than the selected limit, a calculator calculates trajectory characteristics such a the origin and destination of the ballistic projectile.

  1. Intact capture of hypervelocity projectiles.

    PubMed

    Tsou, P

    1990-01-01

    The ability to capture projectiles intact at hypervelocities opens new applications in science and technology that would either not be possible or would be very costly by other means. This capability has been demonstrated in the laboratory for aluminum projectiles of 1.6 mm diameter, captured at 6 km/s, in one unmelted piece, and retaining up to 95% of the original mass. Furthermore, capture was accomplished passively using microcellular underdense polymer foam. Another advantage of capturing projectiles in an underdense medium is the ability of such a medium to preserve a record of the projectile's original velocity components of speed and direction. A survey of these experimental results is described in terms of a dozen parameters which characterize the amount of capture and the effect on the projectile due to different capture media. PMID:11538362

  2. Air-Powered Projectile Launcher

    NASA Technical Reports Server (NTRS)

    Andrews, T.; Bjorklund, R. A.; Elliott, D. G.; Jones, L. K.

    1987-01-01

    Air-powered launcher fires plastic projectiles without using explosive propellants. Does not generate high temperatures. Launcher developed for combat training for U.S. Army. With reservoir pressurized, air launcher ready to fire. When pilot valve opened, sleeve (main valve) moves to rear. Projectile rapidly propelled through barrel, pushed by air from reservoir. Potential applications in seismic measurements, avalanche control, and testing impact resistance of windshields on vehicles.

  3. Possible ground-state octupole deformation in /sup 229/Pa

    SciTech Connect

    Ahmad, I.; Gindler, J.E.; Betts, R.R.; Chasman, R.R.; Friedman, A.M.

    1982-12-13

    Evidence is presented for the occurrence of a (5/2)/sup + -/ parity doublet as the ground state of /sup 229/Pa, in agreement with a previous theoretical prediction. The doublet splitting energy is measured to be 0.22 +- 0.05 keV. The relation of this doublet to ground-state octupole deformation is discussed. .ID LV2109 .PG 1762 1764

  4. Octupole Deformation and Signature Inversion in 145Ba

    NASA Astrophysics Data System (ADS)

    Zhu, Sheng-jiang; Sakhaee, M.; Hamilton H., J.; Ramayya V., A.; Gan, Cui-yun; Zhu, Ling-yan; Yang, Li-ming; Long, Gui-lu; Pau, San-li; Babu R. S., B.; Hwang K., J.; Ma C., W.; Komicki, J.; Zhang Q., X.; Jones F., E.; Cole D., J.; Aryaeinejad, R.; Drigert W., M.; Rasmussen O., J.; Stoyer A., M.; Chu Y., S.; Gregorich E., K.; Mohar F., M.; Prussin G., S.; Lee Y., I.; Yu., Oganessian Ts.; Ter-Akopian M., G.; Daniel V., A.

    1999-10-01

    High spin states in neutron-rich odd-N 145Ba nucleus have been investigated from study of prompt γ-rays in spontaneous fission of 252Cf. The alternating parity bands are identified indicating octupole deformation with simplex quantum number s = -i. The ground state band shows signature splitting and inversion at low spin. These collective band structures exhibit the competition and co-existence between symmetric and asymmetric shapes.

  5. Projectile penetration into ballistic gelatin.

    PubMed

    Swain, M V; Kieser, D C; Shah, S; Kieser, J A

    2014-01-01

    Ballistic gelatin is frequently used as a model for soft biological tissues that experience projectile impact. In this paper we investigate the response of a number of gelatin materials to the penetration of spherical steel projectiles (7 to 11mm diameter) with a range of lower impacting velocities (<120m/s). The results of sphere penetration depth versus projectile velocity are found to be linear for all systems above a certain threshold velocity required for initiating penetration. The data for a specific material impacted with different diameter spheres were able to be condensed to a single curve when the penetration depth was normalised by the projectile diameter. When the results are compared with a number of predictive relationships available in the literature, it is found that over the range of projectiles and compositions used, the results fit a simple relationship that takes into account the projectile diameter, the threshold velocity for penetration into the gelatin and a value of the shear modulus of the gelatin estimated from the threshold velocity for penetration. The normalised depth is found to fit the elastic Froude number when this is modified to allow for a threshold impact velocity. The normalised penetration data are found to best fit this modified elastic Froude number with a slope of 1/2 instead of 1/3 as suggested by Akers and Belmonte (2006). Possible explanations for this difference are discussed. PMID:24184862

  6. Prevention of breakdown behind railgun projectiles

    SciTech Connect

    Hawke, R.S.

    1989-04-20

    An electromagnetic railgun accelerator system, for accelerating projectiles by a plasma arc, introduces a breakdown inhibiting gas into the railgun chamber behind the accelerating projectile. The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF{sub 6}. The gas is introduced between the railgun rails after the projectile has passed through inlets in the rails or the projectile; by coating the rails or the projectile with a material which releases the gas after the projectile passes over it; by fabricating the rails or the projectile or insulators out of a material which releases the gas into the portions of the chamber through which the projectile has traveled. The projectile may have a cavity at its rear to control the release of ablation products. 9 figs.

  7. Prevention of breakdown behind railgun projectiles

    DOEpatents

    Hawke, Ronald S.

    1992-01-01

    An electromagnetic railgun accelerator system, for accelerating projectiles (14, 15, 114, 214, 314, 414) by a plasma arc (3), introduces a breakdown inhibiting gas into the railgun chamber (26) behind the accelerating projectile (14). The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF.sub.6. The gas is introduced between the railgun rails (12) after the projectile (14) has passed through inlets (16) in the rails (12) or the projectile (114); by coating the rails (12) or the projectile (15) with a material (28) which releases the gas after the projectile (14) passes over it; by fabricating the rails (12) or the projectile (15) or insulators out of a material which releases the gas into the portions of the chamber (26) through which the projectile has travelled. The projectile (214, 314, 414) may have a cavity (232, 332, 432) at its rear to control the release of ablation products (4).

  8. Prevention of breakdown behind railgun projectiles

    DOEpatents

    Hawke, Ronald S.

    1992-01-01

    An electromagnetic railgun accelerator system, for accelerating projectiles (14, 15, 114, 214, 314, 444) by a plasma arc (3), introduces a breakdown inhibiting gas into the railgun chamber (26) behind the accelerating projectile (14). The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF.sub.6. The gas is introduced between the railgun rails (12) after the projectile (14) has passed through inlets (16) in the rails (12) or the projectile (114); by coating the rails (12) or the projectile (15) with a material (28) which releases the gas after the projectile (14 ) passes over it; by fabricating the rails (12) or the projectile (15) or insulators out of a material which releases the gas into the portions of the chamber (26) through which the projectile has travelled. The projectile (214, 314, 414) may have a cavity (232, 332, 432) at its rear to control the release of ablation products (4).

  9. Prevention of breakdown behind railgun projectiles

    DOEpatents

    Hawke, R.S.

    1992-10-13

    An electromagnetic railgun accelerator system, for accelerating projectiles by a plasma arc, introduces a breakdown inhibiting gas into the railgun chamber behind the accelerating projectile. The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF[sub 6]. The gas is introduced between the railgun rails after the projectile has passed through inlets in the rails or the projectile; by coating the rails or the projectile with a material which releases the gas after the projectile passes over it; by fabricating the rails or the projectile or insulators out of a material which releases the gas into the portions of the chamber through which the projectile has travelled. The projectile may have a cavity at its rear to control the release of ablation products. 12 figs.

  10. Prevention of breakdown behind railgun projectiles

    DOEpatents

    Hawke, R.S.

    1992-09-01

    An electromagnetic railgun accelerator system, for accelerating projectiles by a plasma arc, introduces a breakdown inhibiting gas into the railgun chamber behind the accelerating projectile. The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF[sub 6]. The gas is introduced between the railgun rails after the projectile has passed through inlets in the rails or the projectile; by coating the rails or the projectile with a material which releases the gas after the projectile passes over it; by fabricating the rails or the projectile or insulators out of a material which releases the gas into the portions of the chamber through which the projectile has travelled. The projectile may have a cavity at its rear to control the release of ablation products. 12 figs.

  11. Octupole deformation in sup 221 Fr; E1 transition rates

    SciTech Connect

    Liang, C.F.; Peghaire, A. ); Sheline, R.K. )

    1990-07-10

    Experimental data following the alpha decay of{sup 225}Ac are interpreted in terms of a spectroscopy in {sup 221}Fr consistent with octupole deformation. However, the measured E1 transition probabilities suggest that the low lying bands in {sup 221}Fr are considerably more mixed than in nuclei with slightly higher mass number. It is suggested that this mixing of states in {sup 221}Fr is indicative of the partial collapse of Nilsson-like orbitals into more degenerate shell model orbitals.

  12. High. beta. studies in the Wisconsin Toroidal Octupole

    SciTech Connect

    Halle, J. H.; Kellman, A.; Post, R. S.; Prager, S. C.; Strait, E. J.; Zarnstorff, M. C.

    1980-09-01

    A wide range of MHD stable high ..beta.. plasmas is produced in the Wisconsin Levitated Octupole. At or near the single fluid regime we obtain, in the bad curvature region, ..beta.. = nk(T/sub e/ + T/sub i/)8..pi../B/sup 2/ approx. = 8%, twice the theoretical single fluid ballooning instability limit of 4%. We also obtain stable plasmas at ..beta.. approx. = 35%, 9 times the theoretical limit, in a regime in which both finite ion gyroradius and gyroviscosity effects are important.

  13. Two-Phonon Octupole Excitation in 146Gd

    SciTech Connect

    Caballero, L.; Rubio, B.; Algora, A.; Nacher, E.; Kleinheinz, P.; Dewald, A.; Fitzler, A.; Jolie, J.; Linnemann, A.; Moeller, O.; Gadea, A.; Julin, R.; Piiparinen, M.; Lunardi, S.; Menegazzo, R.; Yates, S.W.

    2005-11-21

    The excited states in 146Gd have been re-investigated with the 144Sm({alpha},2n) reaction using a modern Ge {gamma}-ray array including a polarimeter. Amongst the non-yrast states populated in this reaction we have identified the aligned 6+ member of the two-phonon octupole quartet from the observation of the E3 branching to the one phonon 3- state. Our results represent the first observation of a 6+{yields}3-{yields}0+ E3 cascade in an even-even nucleus.

  14. Two-Phonon Octupole Excitation in 146Gd

    SciTech Connect

    Caballero, L.; Rubio, B.; Nacher, E.; Kleinheinz, P.; Algora, A.; Blomqvist, J.; Dewald, A.; Fitzler, A.; Jolie, J.; Linnemann, A.; Moeller, O.; Gadea, A.; Julin, R.; Piiparinen, M.; Lunardi, S.; Menegazzo, R.; Yates, S. W.

    2006-04-26

    The excited states in 146Gd have been re-investigated with the 144Sm({alpha},2n) reaction using a modern Ge {gamma}-ray array including a polarimeter. Amongst the non-yrast states populated in this reaction we have identified the aligned 6+ member of the two-phonon octupole quartet from the observation of the E3 branching to the one phonon 3- state. Our results represent the first observation of a 6+{yields}3-{yields}0+ E3 cascade in an even-even nucleus.

  15. Proposed s =±1 octupole bands in 140Xe

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Zhu, S. J.; Hamilton, J. H.; Wang, E. H.; Ramayya, A. V.; Xiao, Z. G.; Li, H. J.; Luo, Y. X.; Rasmussen, J. O.; Ter-Akopian, G. M.; Oganessian, Yu. Ts.

    2016-06-01

    Level structures of neutron-rich 140Xe nucleus have been reinvestigated by using a triple γ coincidence study from the spontaneous fission of 252Cf. Several new levels and transitions are identified. The previously observed s =+1 octupole band structure is confirmed and expanded. Another set of the Δ I =2 positive and negative parity bands connected by strong E 1 transitions is proposed as the s =-1 octupole band structure. Thus, the s =±1 doublet octupole bands are completed in 140Xe. The experimental B (E 1 )/B (E 2 ) branching ratios indicate that the octupole correlations in 140Xe are weak. The other characteristics of the s =±1 octupole bands have been discussed.

  16. Multiple impacts of dusty projectiles

    NASA Astrophysics Data System (ADS)

    Kothe, Stefan; Güttler, Carsten; Blum, Jurgen

    In the context of early stages of planetesimal formation we performed laboratory and drop tower experiments to study multiple impacts of small dust-aggregate projectiles into solid sintered dust targets. Both collision partners consisted of 1.5 µm monodisperse spherical SiO2 monomers with volume filling factors of 0.15 (projectiles) and 0.35 (targets), respectively. The fragile projectiles were accelerated by a solenoid accelerator with a linear projectile magazine, which enabled us to perform 25 impacts within 4.5 s of microgravity time in the Bremen drop tower. We measured the mass-accretion efficiency for different impact velocities between 3 and 5 m s-1 , using an analytical balance and imaging methods. Furthermore, we observed random collisions among small dust aggregates with sizes around 1 mm and collision velocities of the order of 0.25 m s-1 and used them to improve the dust-aggregate collision model of Güttler et al. (2010). u

  17. Projectile Motion Without Trigonometric Functions

    NASA Astrophysics Data System (ADS)

    Mohazzabi, Pirooz; Kohneh, Zahra A.

    2005-02-01

    In this paper we provide a treatment of projectile motion that is accessible to students who are unfamiliar with trigonometry but do have a minimal knowledge of elementary algebra and know the Pythagorean theorem. In this approach, we view the initial velocity of the projectile as being a combination of a vertical part (component) v0V and a horizontal component v0H (see Fig. 1). This is in contrast to the usual approach of taking the initial speed v0 and the launch angle as being given. We let the initial position be the origin and neglect air drag. Assuming that the constant acceleration kinematics equations are known, we may write vH = v0H, and the horizontal distance traveled is x = v0H t, where t is the elapsed time. We also have vV = v0V - gt, where g is the magnitude of the acceleration due to gravity. And the vertical displacement is y = v0V t - ½ gt2. These equations may be used to find the location and velocity of the projectile at any time t. We can also find the equation of the path of the projectile by combining Eq. [1(b)] and Eq. [2(b)] to get y = -(g/2v0H2)x2 + (v0V/v0H) x, which is the equation of a concave-down parabola.

  18. Projectile-generating explosive access tool

    SciTech Connect

    Jakaboski, Juan-Carlos; Hughs, Chance G; Todd, Steven N

    2013-06-11

    A method for generating a projectile using an explosive device that can generate a projectile from the opposite side of a wall from the side where the explosive device is detonated. The projectile can be generated without breaching the wall of the structure or container. The device can optionally open an aperture in a solid wall of a structure or a container and form a high-kinetic-energy projectile from the portion of the wall removed to create the aperture.

  19. Having Fun with a 3-D Projectile

    ERIC Educational Resources Information Center

    Lammi, Matthew; Greenhalgh, Scott

    2011-01-01

    The use of projectiles is a concept familiar to most students, whether it is a classic slingshot, bow and arrow, or even a spit wad through a straw. Perhaps the last thing a teacher wants is more projectiles in the classroom. However, the concept of projectiles is relevant to most students and may provide a means of bringing more authenticity into…

  20. Octupole deformation properties of the Barcelona-Catania-Paris energy density functionals

    SciTech Connect

    Robledo, L. M.; Baldo, M.; Schuck, P.; Vinas, X.

    2010-03-15

    We discuss the octupole deformation properties of the recently proposed Barcelona-Catania-Paris (BCP) energy density functionals for two sets of isotopes, those of radium and barium, in which it is believed that octupole deformation plays a role in the description of the ground state. The analysis is carried out in the mean field framework (Hartree-Fock-Bogoliubov approximation) by using the axially symmetric octupole moment as a constraint. The main ingredients entering the octupole collective Hamiltonian are evaluated and the lowest-lying octupole eigenstates are obtained. In this way we restore, in an approximate way, the parity symmetry spontaneously broken by the mean field and also incorporate octupole fluctuations around the ground-state solution. For each isotope the energy of the lowest lying 1{sup -} state and the B(E1) and B(E3) transition probabilities have been computed and compared to both the experimental data and the results obtained in the same framework with the Gogny D1S interaction, which are used here as a well-established benchmark. Finally, the octupolarity of the configurations involved in the way down to fission of {sup 240}Pu, which is strongly connected to the asymmetric fragment mass distribution, is studied. We confirm with this thorough study the suitability of the BCP functionals to describe octupole-related phenomena.

  1. Ablative shielding for hypervelocity projectiles

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle A. (Inventor)

    1993-01-01

    A hypervelocity projectile shield which includes a hollow semi-flexible housing fabricated from a plastic like, or otherwise transparent membrane which is filled with a fluid (gas or liquid) is presented. The housing has a inlet valve, similar to that on a tire or basketball, to introduce an ablating fluid into the housing. The housing is attached by a Velcro mount or double-sided adhesive tape to the outside surface of a structure to be protected. The housings are arrayed in a side-by-side relationship for complete coverage of the surface to be protected. In use, when a hypervelocity projectile penetrates the outer wall of a housing it is broken up and then the projectile is ablated as it travels through the fluid, much like a meteorite 'burns up' as it enters the earth's atmosphere, and the housing is deflated. The deflated housing can be easily spotted for replacement, even from a distance. Replacement is then accomplished by simply pulling a deflated housing off the structure and installing a new housing.

  2. Wind-influenced projectile motion

    NASA Astrophysics Data System (ADS)

    Bernardo, Reginald Christian; Perico Esguerra, Jose; Day Vallejos, Jazmine; Jerard Canda, Jeff

    2015-03-01

    We solved the wind-influenced projectile motion problem with the same initial and final heights and obtained exact analytical expressions for the shape of the trajectory, range, maximum height, time of flight, time of ascent, and time of descent with the help of the Lambert W function. It turns out that the range and maximum horizontal displacement are not always equal. When launched at a critical angle, the projectile will return to its starting position. It turns out that a launch angle of 90° maximizes the time of flight, time of ascent, time of descent, and maximum height and that the launch angle corresponding to maximum range can be obtained by solving a transcendental equation. Finally, we expressed in a parametric equation the locus of points corresponding to maximum heights for projectiles launched from the ground with the same initial speed in all directions. We used the results to estimate how much a moderate wind can modify a golf ball’s range and suggested other possible applications.

  3. Plasma resistivity measurements in the Wisconsin levitated octupole

    SciTech Connect

    Brouchous, D. A.

    1980-11-01

    Resistivity measurements parallel to the magnetic field were made on gun injected plasmas ranging in density from 10/sup 9/cm/sup -3/ to 10/sup 1/parallelcm/sup -3/ in the Wisconsin levitated octupole with toroidal and poloidal magnetic fields. The 10/sup 9/cm/sup -3/ plasma was collisionless with lambda/sub mfp/ > 100 mirror lengths, had T/sub e/ = 10 eV, T/sub i/ = 30 eV and was found to have anomalous resistivity scaling like eta = ..sqrt..T/sub e//n/sub e/ when E/sub parallel/ > E/su c/ is the Dreicer critical field. The 10/sup 12/cm/sup -3/ plasma was collisional with lambda/sub mfp/ < mirror length, had T/sub e/ = T/sub i/ approx. = .2 eV and was found to have Spitzer resistivity when E/sub parallel/ < E/sub c/.

  4. Search for two-phonon octupole excitations in 146Gd

    NASA Astrophysics Data System (ADS)

    Orce, J. N.; Kumar Raju, M.; Khumalo, N. A.; Dinoko, T. S.; Jones, P.; Bark, R. A.; Lawrie, E. A.; Majola, S. N. T.; Robledo, L. M.; Rubio, B.; Wiedeking, M.; Easton, J.; Khaleel, E. A.; Kheswa, B. V.; Kheswa, N.; Herbert, M. S.; Lawrie, J. J.; Masiteng, P. L.; Nchodu, M. R.; Ndayishimye, J.; Negi, D.; Noncolela, S. P.; Ntshangase, S. S.; Papka, P.; Roux, D. G.; Shirinda, O.; Sithole, P. S.; Yates, S. W.

    2016-06-01

    The low-spin structure of the nearly spherical nucleus 146Gd was studied using the 144Sm(4He, 2n) fusion-evaporation reaction. High-statistics γ - γ coincidence measurements were performed at iThemba LABS with 7× 109 γ- γ coincidence events recorded. Gated γ-ray energy spectra show evidence for the 6+2 → 3-1 → 0+1 cascade of E3 transitions in agreement with recent findings by Caballero and co-workers, but with a smaller branching ratio of I_{γ} = 4.7(10) for the 6+2 → 3-1 1905.1 keV γ ray. Although these findings may support octupole vibrations in spherical nuclei, sophisticated beyond mean-field calculations including angular-momentum projection are required to interpret in an appropriate way the available data due to the failure of the rotational model assumptions in this nucleus.

  5. Sequential injection gas guns for accelerating projectiles

    DOEpatents

    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.

  6. Heart-shaped nuclei: Condensation of rotational-aligned octupole phonons

    SciTech Connect

    Frauendorf, S.

    2008-02-15

    The strong octupole correlations in the mass region A{approx_equal}226 are interpreted as rotation-induced condensation of octupole phonons having their angular momentum aligned with the rotational axis. Discrete phonon energy and parity conservation generate oscillations of the energy difference between the lowest rotational bands with positive and negative parity. Anharmonicities tend to synchronize the rotation of the condensate and the quadrupole shape of the nucleus forming a rotating heart shape.

  7. Octupole correlations in the 144Ba nucleus described with symmetry-conserving configuration-mixing calculations

    NASA Astrophysics Data System (ADS)

    Bernard, Rémi N.; Robledo, Luis M.; Rodríguez, Tomás R.

    2016-06-01

    We study the interplay of quadrupole and octupole degrees of freedom in the structure of the isotope 144Ba. A symmetry-conserving configuration-mixing method (SCCM) based on a Gogny energy density functional (EDF) has been used. The method includes particle number, parity, and angular momentum restoration as well as axial quadrupole and octupole shape mixing within the generator coordinate method. Predictions both for excitation energies and electromagnetic transition probabilities are in good agreement with the most recent experimental data.

  8. Projectile-generating explosive access tool

    DOEpatents

    Jakaboski, Juan-Carlos; Todd, Steven N.

    2011-10-18

    An explosive device that can generate a projectile from the opposite side of a wall from the side where the explosive device is detonated. The projectile can be generated without breaching the wall of the structure or container. The device can optionally open an aperture in a solid wall of a structure or a container and form a high-kinetic-energy projectile from the portion of the wall removed to create the aperture.

  9. Projectile Motion Gets the Hose

    NASA Astrophysics Data System (ADS)

    Goff, John Eric; Liyanage, Chinthaka

    2011-10-01

    Students take a weekly quiz in our introductory physics course. During the week in which material focused on projectile motion, we not-so-subtly suggested what problem the students would see on the quiz. The quiz problem was an almost exact replica of a homework problem we worked through in the class preceding the quiz. The goal of the problem is to find the launch speed if the final horizontal and vertical positions and launch angle are given. Figure 1 shows a schematic of the trajectory.

  10. REDUCED ENERGY CONSUMPTION THROUGH PROJECTILE BASED EXCAVATION

    SciTech Connect

    Mark Machina

    2002-10-12

    The Projectile Based Excavation (ProjEX) program has as its goal, the reduction of energy required for production mining and secondary breakage through the use of a projectile based excavation system. It depends on the development of a low cost family of projectiles that will penetrate and break up different types of ore/rock and a low cost electric launch system. The electric launch system will eliminate the need for high cost propellant investigated for similar concepts in the past. This document reports on the progress made in the program during the past quarter. It reports on projectile development and the development of the electric launch system design.

  11. Projectile development for railguns using hypervelocity preacceleration

    SciTech Connect

    Susoeff, A.R.; Hawke, R.S.; Sauve, G.L.; Konrad, C.H.; Hickman, R.J.

    1991-02-01

    The STARFIRE Project is a joint Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories (SNL) effort to achieve hypervelocity projectile launches up to 15 km/s. The apparatus used to achieve this goal is a three stage acceleration system made up of a two-stage light-gas gun (2SLGG) is used as a preaccelerator capable of injecting 2 gram projectiles at velocities of 6 km/s or more. Projectiles used in this environment are subject to many conditions. Some of these which effect projectile design include: acceleration loading, structural response, barrel condition and alignment. Development of a projectile to satisfy the programmatic requirements is underway. This report covers the evolution of design and fabrication for railgun projectiles from previous experience at LLNL to the replenished plasma armature and projectile now used on STARFIRE. Projectile design, development and fabrication methods which use off-the-shelf materials and standard techniques to meet the operational criteria of the experimental program are discussed in this paper. Initial work involving the design and fabrication of skirted projectiles, which are expected to further reduce interaction phenomena between the plasma armature and railgun barrel, is also described.

  12. Projectile development for railguns using hypervelocity preacceleration

    SciTech Connect

    Susoeff, A.R.; Hawke, R.S. ); Ang, J.A.; Asay, J.R.; Hall, C.A.; Konrad, C.H. ); Sauve, G.L. . Rocky Flats Plant); Hickman, R.J. )

    1992-03-20

    The STARFIRE Project is a joint Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories (SNL) effort to achieve hypervelocity projectile launches up to 15 km/s. The apparatus used to achieve this goal is a three stage acceleration system made up of a two-stage light-gas gun (2SLGG) coupled to a railgun. The 2SLGG is used as a preaccelerator capable of injecting 2 gram projectiles at velocities of 6 km/s or more. Projectiles used in this environment are subject to many conditions. Some of these which effect projectile design include: acceleration loading, structural response, barrel condition and alignment. Development of a projectile to satisfy the programmatic requirements is underway. This report covers the evolution of design and fabrication for railgun projectiles from previous experiment at LLNL to the replenished plasma armature and projectile now used on STARFIRE. Projectile design, development and fabrication methods which use off-the-shelf materials and standard techniques to meet the operational criteria of the experimental program are discussed in this paper. Initial work involving the design and fabrication of skirted projectiles, which are expected to further reduce interaction phenomena between the plasma armature and railgun barrel, is also described.

  13. Stopping power: Effect of the projectile deceleration

    SciTech Connect

    Kompaneets, Roman Ivlev, Alexei V.; Morfill, Gregor E.

    2014-11-15

    The stopping force is the force exerted on the projectile by its wake. Since the wake does not instantly adjust to the projectile velocity, the stopping force should be affected by the projectile deceleration caused by the stopping force itself. We address this effect by deriving the corresponding correction to the stopping force in the cold plasma approximation. By using the derived expression, we estimate that if the projectile is an ion passing through an electron-proton plasma, the correction is small when the stopping force is due to the plasma electrons, but can be significant when the stopping force is due to the protons.

  14. REDUCED ENERGY CONSUMPTION THROUGH PROJECTILE BASED EXCAVATION

    SciTech Connect

    Mark Machina

    2002-01-09

    The Projectile Based Excavation (ProjEX) program has as its goal, the reduction of energy required for production mining and secondary breakage through the use of a projectile based excavation system. It depends on the development of a low cost family of projectiles that will penetrate and break up different types of ore/rock and a low cost electric launch system. The electric launch system will eliminate the need for high cost propellant considered for similar concepts in the past. This document reports on the progress made in the program during the past quarter. It reports on projectile development experiments and the development of the electric launch system design.

  15. Projectile development for railguns using hypervelocity preacceleration

    NASA Astrophysics Data System (ADS)

    Susoeff, A. R.; Hawke, R. S.; Ang, J. A.; Asay, J. R.; Hall, C. A.; Konrad, C. H.; Sauve, G. L.

    1992-03-01

    The STARFIRE Project is a joint Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories (SNL) effort to achieve hypervelocity projectile launches up to 15 km/s. The apparatus used to achieve this goal is a three stage acceleration system made up of a two-stage light-gas gun (2SLGG) coupled to a railgun. The 2SLGG is used as a preaccelerator capable of injecting 2 gram projectiles at velocities of 6 km/s or more. Projectiles used in this environment are subject to many conditions. Some of these which effect projectile design include acceleration loading, structural response, barrel condition and alignment. Development of a projectile to satisfy the programmatic requirements is underway. This report covers the evolution of design and fabrication for railgun projectiles from previous experimentation at LLNL to the replenished plasma armature and projectile now used on STARFIRE. Projectile design, development and fabrication methods which use off-the-shelf materials and standard techniques to meet the operational criteria of the experimental program are discussed in this paper. Initial work involving the design and fabrication of skirted projectiles, which are expected to further reduce interaction phenomena between the plasma armature and railgun barrel, is also described.

  16. Influence of the octupole mode on nuclear high-K isomeric properties

    NASA Astrophysics Data System (ADS)

    Minkov, Nikolay; Walker, Phil

    2014-05-01

    The influence of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even actinide (U, Pu, Cm, Fm, No), rare-earth (Nd, Sm and Gd), and superheavy (^{270}\\text{Ds}) nuclei is examined within a deformed shell model with pairing interaction. The neutron two-quasiparticle (2qp) isomeric energies and magnetic dipole moments are calculated over a wide range in the plane of quadrupole and octupole deformations. In most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation. At the same time, the calculations outline three different groups of nuclei: with pronounced, shallow, and missing minima in the 2qp energy surfaces with respect to the octupole deformation. The result indicates regions of nuclei with octupole softness as well as with possible octupole deformation in the high-K isomeric states. These findings show the need for further theoretical analysis as well as of detailed experimental measurements of magnetic moments in heavy deformed nuclei.

  17. Aerodynamic flail for a spinning projectile

    DOEpatents

    Cole, James K.

    1990-05-01

    A flail is provided which reduces the spin of a projectile in a recovery system which includes a parachute, a cable connected to the parachute, a swivel, and means for connecting the swivel to the projectile. The flail includes a plurality of flexible filaments and a rotor for attaching the filaments to the front end of the projectile. The rotor is located radially with respect to the spinning axis of the projectile. In one embodiment, the projectile includes a first nose cone section housing a deployable spin damping assembly; a second nose cone section, housing a deployable parachute assembly; a shell section, supporting the first and second nose cone sections during flight of the projectile; a mechanism for releasing the first nose cone section from the second cone section; and a mechanism for releasing the second nose cone section from the shell section. In operation of this embodiment, the deployable spin damping assembly deploys during flight of the projectile when the mechanism for releasing the first nose cone section from the second nose cone section are actuated. Then, upon actuation of the mechanism for releasing the second nose cone section from the shell section, two things happen: the spin damping assembly separates from the projectile; and the deployable parachute assembly is deployed.

  18. Aerodynamic flail for a spinning projectile

    DOEpatents

    Cole, James K.

    1990-01-01

    A flail is provided which reduces the spin of a projectile in a recovery system which includes a parachute, a cable connected to the parachute, a swivel, and means for connecting the swivel to the projectile. The flail includes a plurality of flexible filaments and a rotor for attaching the filaments to the front end of the projectile. The rotor is located radially with respect to the spinning axis of the projectile. In one embodiment, the projectile includes a first nose cone section housing a deployable spin damping assembly; a second nose cone section, housing a deployable parachute assembly; a shell section, supporting the first and second nose cone sections during flight of the projectile; a mechanism for releasing the first nose cone section from the second cone section; and a mechanism for releasing the second nose cone section from the shell section. In operation of this embodiment, the deployable spin damping assembly deploys during flight of the projectile when the mechanism for releasing the first nose cone section from the second nose cone section are actuated. Then, upon actuation of the mechanism for releasing the second nose cone section from the shell section, two things happen: the spin damping assembly separates from the projectile; and the deployable parachute assembly is deployed.

  19. Graphical Method for Determining Projectile Trajectory

    ERIC Educational Resources Information Center

    Moore, J. C.; Baker, J. C.; Franzel, L.; McMahon, D.; Songer, D.

    2010-01-01

    We present a nontrigonometric graphical method for predicting the trajectory of a projectile when the angle and initial velocity are known. Students enrolled in a general education conceptual physics course typically have weak backgrounds in trigonometry, making inaccessible the standard analytical calculation of projectile range. Furthermore,…

  20. Three-phase hypervelocity projectile launcher

    DOEpatents

    Fugelso, L. Erik; Langner, Gerald C.; Burns, Kerry L.; Albright, James N.

    1994-01-01

    A hypervelocity projectile launcher for use in perforating borehole casings provides improved penetration into the surrounding rock structure. The launcher includes a first cylinder of explosive material that defines an axial air-filled cavity, a second cylinder of explosive material defining an axial frustum-shaped cavity abutting and axially aligned with the first cylinder. A pliant washer is located between and axially aligned with the first and second cylinders. The frustum shaped cavity is lined with a metal liner effective to form a projectile when the first and second cylinders are detonated. The washer forms a unique intermediate projectile in advance of the liner projectile and enables the liner projectile to further penetrate into and fracture the adjacent rock structure.

  1. REDUCED ENERGY CONSUMPTION THROUGH PROJECTILE BASED EXCAVATION

    SciTech Connect

    Unknown

    2001-10-12

    The hypothesis to be tested is that the addition of steel or other synthetic fiber and/or high strength, low cost aggregate to strong grouts or concrete will result in a projectile of sufficient strength to produce cracking and spall enough to make its use cost effective for mining. Based on experiments conducted to date, no conclusions can yet be reached. Results of the experiments conducted suggest that reinforcement of a concrete projectile can yield performance that portends cost effective projectile based excavation. It is recognized that the projectile is but one component of the matrix. The electric launch system to be developed in the next phase of the program is the other factor that weighs heavily in the cost effectiveness equation. At this point, however, emerging low cost options for the projectile are very promising.

  2. Observation of the Nuclear Magnetic Octupole Moment of 137Ba+

    NASA Astrophysics Data System (ADS)

    Hoffman, Matthew

    Single trapped ions are ideal systems in which to test atomic physics at high precision, which can in turn be used for searches for violations of fundamental symmetries and physics beyond the standard model, in addition to quantum computation and a number of other applications. The ion is confined in ultra-high vacuum, is laser cooled to mK temperatures, and kept well isolated from the environment which allows these experimental efforts. In this thesis, a few diagnostic techniques will be discussed, covering a method to measure the linewidth of a narrowband laser in the presence of magnetic field noise, as well as a procedure to measure the ion's temperature using such a narrowband laser. This work has led to two precision experiments to measure atomic structure in 138Ba+, and 137Ba+ discussed here. First, employing laser and radio frequency spectroscopy techniques in 138Ba+, we measured the Lande- gJ factor of the 5D5/2 level at the part-per-million level, the highest precision to date. Later, the development of apparatus to efficiently trap and laser cool 137Ba+ has enabled a measurement of the hyperfine splittings of the 5D3/2 manifold, culminating in the observation of the nuclear magnetic octupole moment of 137Ba+.

  3. Stable and Vibrational Octupole Modes in Mo, Xe, Ba, La, Ce and Nd

    SciTech Connect

    Gore, P.M.; Hamilton, J.H.; Hwang, J.K.; Jones, E.F.; Peker, L.K.; Ramayya, A.V.; Zhang, X.Q.; Zhu, S.J.

    1998-05-18

    Evidence is presented for stable octupole deformation in neutron-rich nuclei, bounded by Z = 54-58 and N = 85-92. To either side of this region negative parity bands built on more vibrational type octupole modes are observed in {sup 140}Ba and {sup 152,154}Nd. The largest stable octupole deformation ({beta}{sub s} {approximately} 0.1) is found in {sup 144}Ba{sub as}. The theoretically predicted quenching ({beta}{sub s} {approximately} 0) of stable octupole deformation at higher spins is found in {sup 140}Ba. There is good agreement between theory and experiment for the strongly varying electric dipole moments as a function of mass for {sup 142-141}Ba. In odd-A {sup 142}Ba and odd-Z {sup 140}La, we observe parity doublets, two pairs of positive and negative parity bands with opposite spins. In {sup 145}La a strong coupled ground band with symmetric shape coexists with the asymmetric octupole shape which stabilizes above about spin 19/2. In {sup 145,147}La a strong reduction in E2 strength around 25/2 from band crossing is observed. The isotope {sup 109}Mo was identified and a new region of stable uctpole deformation is identified in {sup 107,108}Mo centered around N = 64-66 as earlier predicted. This is the first case of stable uctpole deformation involving only one pair of orbitals.

  4. Projectile channeling in chain bundle dusty plasma liquids: Wave excitation and projectile-wave interaction

    SciTech Connect

    Chang, Mei-Chu; Tseng, Yu-Ping; I, Lin

    2011-03-15

    The microscopic channeling dynamics of projectiles in subexcitable chain bundle dusty plasma liquids consisting of long chains of negatively charged dusts suspended in low pressure glow discharges is investigated experimentally using fast video-microscopy. The long distance channeling of the projectile in the channel formed by the surrounding dust chain bundles and the excitation of a narrow wake associated with the elliptical motions of the background dusts are demonstrated. In the high projectile speed regime, the drag force due to wake wave excitation increases with the decreasing projectile speed. The excited wave then leads the slowed down projectile after the projectile speed is decreased below the resonant speed of wave excitation. The wave-projectile interaction causes the increasing projectile drag below the resonant speed and the subsequent oscillation around a descending average level, until the projectile settles down to the equilibrium point. Long distance projectile surfing through the resonant crest trapping by the externally excited large amplitude solitary wave is also demonstrated.

  5. Projectile dynamics at low barrel pressures

    NASA Astrophysics Data System (ADS)

    Chankaev, S. K.; Yakovlev, V. Ya.

    2007-11-01

    A mathematical model for a projectile shot at low pressures in the space behind the projectile space is developed. The pressure rise is limited because of the nonsimultaneity of propellant ignition and combustion and the discharge of the propellant combustion products through the gap between the projectile and the walls of the gun barrel. The kinetic characteristics of flame propagation over the propellant particles are determined. A comparison of calculation and experimental data is performed. The calculation results are used in designing 2A85 self-propelled launchers and upgrading 2A30 self-propelled launchers.

  6. Effects of barrel joints on hypervelocity projectiles

    SciTech Connect

    Shahinpoor, M.; Asay, J.R.; Dixon, W.R.; Hawke, R.S.

    1987-01-01

    Development of new hypervelocity launchers is necessary for equation of state (EOS) studies at high impact velocities. The requirements for barrel joint alignment and concentricity at high velocities place severe constraints on fabrication and assembly procedures; small steps or longitudinal direction changes at joints may cause major damage to precision projectiles. Research has been initiated to identify the technical limits of fabrication and assembly tolerances for hypervelocity gun barrels. Numerical and experimental studies have evaluated projectile performance at velocities of 6 to 15 km/s and have identified failure modes for Lexan projectiles with thin metal facings.

  7. Reflection asymmetry in odd-A and odd-odd actinium nuclei

    SciTech Connect

    Ahmad, I.

    1993-09-01

    Theoretical calculations and measurements indicate that octupole correlations are at a maximum in the ground states of the odd-proton nuclei Ac and Pa. It has been expected that odd-odd nuclei should have even larger amount of octupole-octupole correlations. We have recently made measurements on the structure of {sup 224}Ac. Although spin and parity assignments could not be made, two bands starting at 354.1 and 360.0 keV have properties characteristic of reflection asymmetric shape. These two bands have very similar rotational constants and also similar alpha decay rates, which suggest similarity between the wavefunctions of these bands. These signatures provide evidence for octupole correlations in these nuclides.

  8. Hypervelocity High Speed Projectile Imagery and Video

    NASA Technical Reports Server (NTRS)

    Henderson, Donald J.

    2009-01-01

    This DVD contains video showing the results of hypervelocity impact. One is showing a projectile impact on a Kevlar wrapped Aluminum bottle containing 3000 psi gaseous oxygen. One video show animations of a two stage light gas gun.

  9. REDUCED ENERGY CONSUMPTION THROUGH PROJECTILE BASED EXCAVATION

    SciTech Connect

    Mark Machina

    2003-06-06

    The Projectile Based Excavation (ProjEX) program has as its goal, the reduction of energy required for production mining and secondary breakage through the use of a projectile based excavation system. It depends on the development of a low cost family of projectiles that will penetrate and break up different types of ore/rock and a low cost electric launch system. The electric launch system will eliminate the need for high cost propellant considered for similar concepts in the past. This document reports on the program findings through the first two phases. It presents projectile design and experiment data and the preliminary design for electric launch system. Advanced Power Technologies, Inc., now BAE SYSTEMS Advanced Technologies, Inc., was forced to withdraw from the program with the loss of one of our principal mining partners, however, the experiments conducted suggest that the approach is feasible and can be made cost effective.

  10. Electromagnetic theta gun and tubular projectiles

    SciTech Connect

    Burgess, T.J.; Cnare, E.C.; Oberkampf, W.L.; Beard, S.G.; Cowan, M.

    1980-12-01

    Unlike the better known rail gun, the theta gun applies the propelling force along the length of its projectile. This is shown to allow much greater acceleration of high fineness ratio projectiles for a given barrel pressure, allowing much shorter barrels for military applications. A computer code which simulates performance of the theta gun is described and experimental results from a few simple, low energy experiments show close agreement with code predictions. Trajectories and aerodynamic heating for three candidate military projectiles are calculated for vertical and horizontal atmospheric launches where initial velocity is as high as 3 km/s. The calculations indicate that in some cases a thin layer of heatshield (ablator) will be required to control projectile heating.

  11. Possible octupole deformation in Cs and Ba nuclei from their differential radii

    SciTech Connect

    Sheline, R.K.; Jain, A.K.; Jain, K.

    1988-12-01

    The odd-even staggering of the differential radii of Fr and Ra and the Cs and Ba nuclei is compared. This staggering is inverted in the region of known octupole deformation in the Fr and Ra nuclei. The normal staggering is eliminated in the Cs nuclei and attenuated in the Ba nuclei for neutron numbers 85--88. This fact is used to suggest the possible existence of octupole deformation and its neutron number range in the Cs and Ba nuclear ground states.

  12. Collective states of odd nuclei in a model with quadrupole-octupole degrees of freedom

    SciTech Connect

    Minkov, N. Drenska, S. B.; Yotov, P.; Bonatsos, D. Scheid, W.

    2007-08-15

    We apply the collective axial quadrupole-octupole Hamiltonian to describe the rotation-vibration motion of odd nuclei with Coriolis coupling between the even-even core and the unpaired nucleon.We consider that the core oscillates coherently with respect to the quadrupole and octupole axialdeformation variables. The coupling between the core and the unpaired nucleon provides a split paritydoublet structure of the spectrum. The formalism successfully reproduces the parity-doublet splitting in a wide range of odd-A nuclei. It provides model estimations for the third angular-momentum projection K on the intrinsic symmetry axis and the related intrinsic nuclear structure.

  13. Influence of octupole interactions on the behavior of negative-parity states at low spins

    SciTech Connect

    Sitdikov, A. S. Safarov, R. Kh.; Kvasil, J.

    2006-12-15

    The energies of negative-parity levels based on two-particle states exhibit a nonlinear behavior at low spins versus the core-rotation energy because the alignment process has not yet been completed for them. This behavior of negative-parity levels in the low-spin region is satisfactorily described upon the inclusion of octupole-octupole interactions. This is demonstrated within the rotational model involving the Coriolis mixing of states for the even-even isotopes {sup 162-168}Hf.

  14. Specifications of the octupole magnets required for the ATF2 ultra-low ß* lattice

    SciTech Connect

    Marin, E.; Modena, M.; Tauchi, T.; Terunuma, N.; Tomas, R.; White, G.R.; /SLAC

    2014-05-28

    The Accelerator Test Facility 2 (ATF2) aims to test the novel chromaticity correction for higher chromaticity lattices as the one of CLIC. To this end the ATF2 ultra-low ß* lattice is designed to vertically focus the beam at the focal point or usually referred to as interaction point (IP), down to 23 nm. However when the measured multipole components of the ATF2 magnets are considered in the simulations, the evaluated spot sizes at the IP are well above the design value. The designed spot size is effectively recovered by inserting a pair of octupole magnets. In this note we address the technical specifications required for these octupole magnets.

  15. Graphical Method for Determining Projectile Trajectory

    NASA Astrophysics Data System (ADS)

    Moore, J. C.; Baker, J. C.; Franzel, L.; McMahon, D.; Songer, D.

    2010-12-01

    We present a nontrigonometric graphical method for predicting the trajectory of a projectile when the angle and initial velocity are known. Students enrolled in a general education conceptual physics course typically have weak backgrounds in trigonometry, making inaccessible the standard analytical calculation of projectile range. Furthermore, research shows that standard instructional techniques fail to confront student misconceptions about motion in a gravitational field.1-4 We have designed a guided inquiry-based lesson that specifically addresses these misconceptions with minimal mathematics.

  16. Elastic scattering with weakly bound projectiles

    SciTech Connect

    Figueira, J. M.; Abriola, D.; Arazi, A.; Capurro, O. A.; Marti, G. V.; Martinez Heinmann, D.; Pacheco, A. J.; Testoni, J. E.; Barbara, E. de; Fernandez Niello, J. O.; Padron, I.; Gomes, P. R. S.; Lubian, J.

    2007-02-12

    Possible effects of the break-up channel on the elastic scattering threshold anomaly has been investigated. We used the weakly bound 6,7Li nuclei, which is known to undergo break-up, as projectiles in order to study the elastic scattering on a 27Al target. In this contribution we present preliminary results of these experiments, which were analyzed in terms of the Optical Model and compared with other elastic scattering data using weakly bound nuclei as projectile.

  17. Octupole Resonance in the AGS at High Intensity: A SIMBAD study

    SciTech Connect

    Luccio, A.U.; D'Imperio, N.L.

    2005-06-08

    We studied the Octupole (Montague) resonance in the AGS, in its high intensity mode, by tracking with the PIC code SIMBAD. We calculated, turn-by-turn, the betatron tune footprint from the eigenvalues of the one-turn matrix. We show that one should exercise particular caution when the betatron tunes are close together, since the matrix gives ambiguous results at the resonance.

  18. Betatron tune spread generation and differential chromaticity control by octupole families at Tevatron

    SciTech Connect

    Ivanov, P.M.; Alexahin, Y.; Annala, J.; Lebedev, V.A.; /Fermilab

    2005-05-01

    Existing Tevatron octupoles have been rearranged into four functional families. Two of these families generate betatron tune spreads in the vertical and horizontal planes whereas the other two control the differential chromaticity between the proton and antiproton helices. The calculated effect on the tunes and chromaticity is compared with direct measurements. Analytical formulas for betatron tune distribution functions are presented.

  19. Octupole deformation in 144,146Ba measured by Coulomb excitation of radioactive beams

    NASA Astrophysics Data System (ADS)

    Bucher, Brian; Zhu, Shaofei; ANL, LBNL, LLNL, Rochester, Florida State, Liverpool, Maryland, Notre Dame, Ohio, W. Scotland Collaboration

    2015-10-01

    The exotic, neutron-rich 144Ba (t1 / 2 = 11.5 s) and 146Ba (t1 / 2 = 2.2 s) nuclei are expected to exhibit some of the strongest octupole correlations in A < 200 systems. Up to now, evidence for such strong octupole correlations has been inferred from observations of low-lying negative-parity states and from the interleaving of positive- and negative-parity levels in the ground-state band. However, the E1 transition strengths are very different in these two nuclei, with two orders of magnitude reduction in 146Ba. In this experiment, we measure the octupole strength directly by Coulomb excitation of post-accelerated 144,146Ba beams produced at CARIBU using CHICO2 and GRETINA. In 144Ba, we found B(E3;3 -->0) = 48(-34+ 25) W.u., a value considerably larger than theoretical predictions, while preliminary results for 146Ba are also indicative of strong octupole collectivity. The experimental conditions, the analysis, and the results from these challenging new measurements will be presented. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357 (ANL), DE-AC02-05CH11231 (LBNL, GRETINA), DOE DE-AC52-07NA27344 (LLNL), and NSF.

  20. Direct evidence of octupole deformation in neutron-rich 144Ba

    DOE PAGESBeta

    Bucher, B.; Zhu, S.; Wu, C. Y.; Janssens, R. V. F.; Cline, D.; Hayes, A. B.; Albers, M.; Ayangeakaa, A. D.; Butler, P. A.; Campbell, C. M.; et al

    2016-03-17

    Here, the neutron-rich nucleus 144Ba (t1/2 = 11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV 144Ba beam on a 1.0–mg/cm2 208Pb target. The measured value of the matrix element, < 31–∥M(E3)∥01+ >= 0.65(+17–23) eb3/2, corresponds to a reduced B(E3) transition probabilitymore » of 48(+25–34) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.« less

  1. Direct Evidence of Octupole Deformation in Neutron-Rich ^{144}Ba.

    PubMed

    Bucher, B; Zhu, S; Wu, C Y; Janssens, R V F; Cline, D; Hayes, A B; Albers, M; Ayangeakaa, A D; Butler, P A; Campbell, C M; Carpenter, M P; Chiara, C J; Clark, J A; Crawford, H L; Cromaz, M; David, H M; Dickerson, C; Gregor, E T; Harker, J; Hoffman, C R; Kay, B P; Kondev, F G; Korichi, A; Lauritsen, T; Macchiavelli, A O; Pardo, R C; Richard, A; Riley, M A; Savard, G; Scheck, M; Seweryniak, D; Smith, M K; Vondrasek, R; Wiens, A

    2016-03-18

    The neutron-rich nucleus ^{144}Ba (t_{1/2}=11.5  s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV ^{144}Ba beam on a 1.0-mg/cm^{2} ^{208}Pb target. The measured value of the matrix element, ⟨3_{1}^{-}∥M(E3)∥0_{1}^{+}⟩=0.65(+17/-23) eb^{3/2}, corresponds to a reduced B(E3) transition probability of 48(+25/-34)  W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation. PMID:27035298

  2. Direct Evidence of Octupole Deformation in Neutron-Rich 144Ba

    NASA Astrophysics Data System (ADS)

    Bucher, B.; Zhu, S.; Wu, C. Y.; Janssens, R. V. F.; Cline, D.; Hayes, A. B.; Albers, M.; Ayangeakaa, A. D.; Butler, P. A.; Campbell, C. M.; Carpenter, M. P.; Chiara, C. J.; Clark, J. A.; Crawford, H. L.; Cromaz, M.; David, H. M.; Dickerson, C.; Gregor, E. T.; Harker, J.; Hoffman, C. R.; Kay, B. P.; Kondev, F. G.; Korichi, A.; Lauritsen, T.; Macchiavelli, A. O.; Pardo, R. C.; Richard, A.; Riley, M. A.; Savard, G.; Scheck, M.; Seweryniak, D.; Smith, M. K.; Vondrasek, R.; Wiens, A.

    2016-03-01

    The neutron-rich nucleus 144Ba (t1 /2=11.5 s ) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E 1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV 144Ba beam on a 1.0 -mg /cm2 208Pb target. The measured value of the matrix element, ⟨31 -∥M (E 3 )∥01 +⟩=0.65 (+17/-23) e b3 /2, corresponds to a reduced B (E 3 ) transition probability of 48 (+25/-34) W .u . This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.

  3. Symmetry of the CMB sky as a new test of its statistical isotropy. Non cosmological octupole?

    SciTech Connect

    Naselsky, P.; Hansen, M.; Kim, J. E-mail: kirstejn@nbi.dk

    2011-09-01

    In this article we propose a novel test for statistical anisotropy of the CMB ΔT( n-circumflex = (θ,φ)). The test is based on the fact, that the Galactic foregrounds have a remarkably strong symmetry with respect to their antipodal points with respect to the Galactic plane, while the cosmological signal should not be symmetric or asymmetric under these transitions. We have applied the test for the octupole component of the WMAP ILC 7 map, by looking at a{sub 3,1} and a{sub 3,3}, and their ratio to a{sub 3,2} both for real and imaginary values. We find abnormal symmetry of the octupole component at the level of 0.58%, compared to Monte Carlo simulations. By using the analysis of the phases of the octupole we found remarkably strong cross-correlations between the phases of the kinematic dipole and the ILC 7 octupole, in full agreement with previous results. We further test the multipole range 2 < l < 100, by investigating the ratio between the l+m = even and l+m = odd parts of power spectra. We compare the results to simulations of a Gaussian random sky, and find significant departure from the statistically isotropic and homogeneous case, for a very broad range of multipoles. We found that for the most prominent peaks of our estimator, the phases of the corresponding harmonics are coherent with phases of the octupole. We believe, our test would be very useful for detections of various types of residuals of the foreground and systematic effects at a very broad range of multipoles 2 ≤ l ≤ 1500−3000 for the forthcoming PLANCK CMB map, before any conclusions about primordial non-Gaussianity and statistical anisotropy of the CMB.

  4. Anharmonicity of the excited octupole band in actinides using supersymmetric quantum mechanics

    NASA Astrophysics Data System (ADS)

    Jolos, R. V.; von Brentano, P.; Casten, R. F.

    2013-09-01

    Background: Low-lying octupole collective excitations play an important role in the description of the structure of nuclei in the actinide region. Ground state alternating parity rotational bands combining both positive and negative parity states are known in several nuclei. However, only recently it has been discovered in 240Pu an excited positive parity rotational band having an octupole nature and demonstrating strong anharmonicity of the octupole motion in the band head energies.Purpose: To suggest a model describing both ground state and excited alternating parity bands, which includes a description of the anharmonic effects in the bandhead excitation energies and can be used to predict the energies of the excited rotational bands of octupole nature and the E1 transition probabilities.Methods: The mathematical technique of the supersymmetric quantum mechanics with a collective Hamiltonian depending only on the octupole collective variable which keeps axial symmetry is used to describe the ground state and excited alternating parity rotational bands.Results: The excitation energies of the states belonging to the lowest negative parity and the excited positive parity bands are calculated for 232Th, 238U, and 240Pu. The E1 transition matrix elements are also calculated for 240Pu.Conclusions: It is shown that the suggested model describes the excitation energies of the states of the lowest negative parity band with the accuracy around 10 keV. The anharmonicity in the bandhead energy of the excited positive parity band is described also. The bandhead energy of the excited positive parity band is described with the accuracy around 100 keV.

  5. Octupole Deformation Bands of πh11/2 in Neutron-Rich 145,147La Nuclei

    NASA Astrophysics Data System (ADS)

    Zhu, Sheng-jiang; S, Zhu J.; Wang, Mu-ge; J, Hamilton H.; A, Ramayya V.; B, Babu R. S.; W, Ma C.; Long, Gui-lu; Zhu, Ling-yan; Li, Ming; A, Sakhaee; Gan, Cui-yun; Yang, Li-ming; J, Komicki; J, Cole D.; R, Aryaeinejad; M, Drigert W.; J, Rasmussen O.; M, Stoyer A.; S, Chu Y.; K, Gregorich E.; M, Mohar F.; S, Prussin G.; I, Lee Y.; Yu, Oganessian Ts; G, Ter-Akopian M.; A, Daniel V.

    1999-03-01

    Octupole deformation bands built on πh11/2 orbital in neutron-rich odd-Z 145,147La nuclei have been investigated by measuring the prompt γ-rays emitted from the 252Cf source. The alternating parity band structures and strong E1 transitions observed between negative- and positive-parity bands in both nuclei indicate the octupole deformation enhanced by the h11/2 single proton coupling. According to observed energy displacements the octupole deformation becomes stable at the intermediate spin states.

  6. Flight trajectory simulation of fluid payload projectiles

    SciTech Connect

    Vaughn, H.R.; Wolfe, W.P.; Oberkampf, W.L.

    1985-01-01

    A flight trajectory simulation method has been developed for calculating the six degree of freedom motion of fluid filled projectiles. Numerically calculated internal fluid moments and experimentally known aerodynamic forces and moments are coupled to the projectile motion. Comparisons of predicted results with flight test data of an M483 155mm artillery projectile with a highly viscous payload confirm the accuracy of the simulation. This simulation clearly shows that the flight instability is due to the growth of the nutation component of angular motion caused by the viscous effects of the fluid payload. This simulation procedure, when used in conjunction with the previously developed method for calculating internal fluid moments, allows the designer to examine the effects of various liquid payloads and container geometries on the dynamic behavior of flight vehicles.

  7. Additional Crime Scenes for Projectile Motion Unit

    NASA Astrophysics Data System (ADS)

    Fullerton, Dan; Bonner, David

    2011-12-01

    Building students' ability to transfer physics fundamentals to real-world applications establishes a deeper understanding of underlying concepts while enhancing student interest. Forensic science offers a great opportunity for students to apply physics to highly engaging, real-world contexts. Integrating these opportunities into inquiry-based problem solving in a team environment provides a terrific backdrop for fostering communication, analysis, and critical thinking skills. One such activity, inspired jointly by the museum exhibit "CSI: The Experience"2 and David Bonner's TPT article "Increasing Student Engagement and Enthusiasm: A Projectile Motion Crime Scene,"3 provides students with three different crime scenes, each requiring an analysis of projectile motion. In this lesson students socially engage in higher-order analysis of two-dimensional projectile motion problems by collecting information from 3-D scale models and collaborating with one another on its interpretation, in addition to diagramming and mathematical analysis typical to problem solving in physics.

  8. Ocular injuries due to projectile impacts.

    PubMed

    Scott, W R; Lloyd, W C; Benedict, J V; Meredith, R

    2000-01-01

    An animal model has been developed using enucleated porcine eyes to evaluate ocular trauma. The eyes were pressurized to approximately 18 mmHg and mounted in a container with a 10% gelatin mixture. The corneas of sixteen pressurized eyes were impacted by a blunt metal projectile (mass of 2.6 gm, 3.5 gm or 45.5 gm) at velocities of 4.0 to 38.1 m/s. The impacted eyes were evaluated by an ophthalmologist. A numerical classification scheme was used to categorize the severity of the ocular injury. A chi-squared test indicates that the injury level is associated with the kinetic energy (KE) and not the momentum of the projectile. The enucleated eyes began to experience lens dislocations when the KE of the projectile was approximately 0.75 Nm, and retinal injuries when the KE was approximately 1.20 Nm. PMID:11558084

  9. Numerical simulations of gun-launched kinetic energy projectiles subjected to asymmetric projectile base pressure

    SciTech Connect

    Rabern, D.A.

    1991-12-31

    Three-dimensional numerical simulations were performed to determine the effect of an asymmetric base pressure on kinetic energy projectiles during launch. A matrix of simulations was performed in two separate launch environments. One launch environment represented a severe lateral load environment, while the other represented a nonsevere lateral load environment based on the gun tube straightness. The orientation of the asymmetric pressure field, its duration, the projectile`s initial position, and the tube straightness were altered to determine the effects of each parameter. The pressure asymmetry translates down the launch tube to exit parameters and is washed out by tube profile. Results from the matrix of simulations are presented.

  10. Molecular dynamics study on the interactions between helium projectiles and helium bubbles pre-existing in tungsten surfaces

    NASA Astrophysics Data System (ADS)

    Ding, Yuan; Ma, Chaoqiong; Li, Min; Hou, Qing

    2016-02-01

    Molecular dynamics simulations were performed to study the interactions between low-energy (⩽100 eV) helium (He) projectiles and helium bubbles pre-existing near tungsten (W) surfaces. It is observed that with increasing bubble size, the reflection coefficient of the He projectiles was reduced, and the channelling effect that could be observed with no pre-existing He bubble was depressed. The He projectiles can be captured by pre-existing He bubbles and also knock He atoms out of the bubbles. The spatial distribution of the single He atoms, including both the slowed-down projectiles and the knocked-out He atoms, was extracted. The single He atoms were found distributed around the bubbles in a region with the width of 3-5.5 in lattice lengths of W. Although the results were obtained for the interaction of He projectiles with isolated He bubbles pre-existing in W, they suggest that the reflection and retention status of He projectiles would change during the irradiation of high flux/fluence He on W surfaces due to the change of He bubbles coverage near W surfaces. The results can be coupled with Monte Carlo modelling in conditions closer to that in experiments of high flux/fluence He bombardments on W surfaces.

  11. Coulomb Excitation with CARIBU Beams: Octupole Strength in 144Ba Measured with GRETINA and CHICO2

    NASA Astrophysics Data System (ADS)

    Bucher, Brian; Zhu, Shaofei; ANL, LBNL, LLNL, Rochester, Florida St, Liverpool, Maryland, Notre Dame, Ohio,; W. Scotland Collaboration

    2014-09-01

    The neutron-rich barium isotopes sit in one of the few mass regions on the nuclear chart observed to display octupole correlations. These isotopes are challenging to study since they lie far from stability and are thus difficult to produce in large quantities. In particular, this region is interesting for studying the evolution of octupole correlations since the enhancement of the E1 strength drops by an order of magnitude from 144Ba to 146Ba, where shell corrections appear to play a significant role. To provide unambiguous insight into the octupole correlations, B(E3) strengths have been measured using Coulomb excitation of 144Ba beams at 650 MeV on a 1 mg/cm2 208Pb target. This experiment represents the first successful measurement utilizing re-accelerated CARIBU beams combined with the γ-ray tracking array GRETINA and the auxiliary charged-particle detector CHICO2. Preliminary results from the experiment will be presented. The neutron-rich barium isotopes sit in one of the few mass regions on the nuclear chart observed to display octupole correlations. These isotopes are challenging to study since they lie far from stability and are thus difficult to produce in large quantities. In particular, this region is interesting for studying the evolution of octupole correlations since the enhancement of the E1 strength drops by an order of magnitude from 144Ba to 146Ba, where shell corrections appear to play a significant role. To provide unambiguous insight into the octupole correlations, B(E3) strengths have been measured using Coulomb excitation of 144Ba beams at 650 MeV on a 1 mg/cm2 208Pb target. This experiment represents the first successful measurement utilizing re-accelerated CARIBU beams combined with the γ-ray tracking array GRETINA and the auxiliary charged-particle detector CHICO2. Preliminary results from the experiment will be presented. This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH

  12. Dynamic effects of interaction of composite projectiles with targets

    NASA Astrophysics Data System (ADS)

    Zakharov, V. M.

    2016-01-01

    The process of high-speed impact of projectiles against targets of finite thickness is experimentally investigated. Medium-hard steel plates are used as targets. The objective of this research is to carry out a comparative analysis of dynamic effects of interaction of various types of projectiles with targets, such as characteristics of destruction of the target, the state of the projectile behind the target, and particularities of the after-penetration stream of fragments after the target has been pierced. The projectiles are made of composites on the basis of tungsten carbide obtained by caking and the SHS-technology. To compare effectiveness of composite projectiles steel projectiles are used. Their effectiveness was estimated in terms of the ballistic limit. High density projectiles obtained by means of the SHS-technology are shown to produce results comparable in terms of the ballistic limit with high-strength projectiles that contain tungsten received by caking.

  13. Speed, Acceleration, Chameleons and Cherry Pit Projectiles

    ERIC Educational Resources Information Center

    Planinsic, Gorazd; Likar, Andrej

    2012-01-01

    The paper describes the mechanics of cherry pit projectiles and ends with showing the similarity between cherry pit launching and chameleon tongue projecting mechanisms. The whole story is written as an investigation, following steps that resemble those typically taken by scientists and can therefore serve as an illustration of scientific…

  14. An Inexpensive Mechanical Model for Projectile Motion

    ERIC Educational Resources Information Center

    Kagan, David

    2011-01-01

    As experienced physicists, we see the beauty and simplicity of projectile motion. It is merely the superposition of uniform linear motion along the direction of the initial velocity vector and the downward motion due to the constant acceleration of gravity. We see the kinematic equations as just the mathematical machinery to perform the…

  15. Speed, acceleration, chameleons and cherry pit projectiles

    NASA Astrophysics Data System (ADS)

    Planinsic, Gorazd; Likar, Andrej

    2012-01-01

    The paper describes the mechanics of cherry pit projectiles and ends with showing the similarity between cherry pit launching and chameleon tongue projecting mechanisms. The whole story is written as an investigation, following steps that resemble those typically taken by scientists and can therefore serve as an illustration of scientific reasoning and how scientific knowledge is built.

  16. Ballistics projectile image analysis for firearm identification.

    PubMed

    Li, Dongguang

    2006-10-01

    This paper is based upon the observation that, when a bullet is fired, it creates characteristic markings on the cartridge case and projectile. From these markings, over 30 different features can be distinguished, which, in combination, produce a "fingerprint" for a firearm. By analyzing features within such a set of firearm fingerprints, it will be possible to identify not only the type and model of a firearm, but also each and every individual weapon just as effectively as human fingerprint identification. A new analytic system based on the fast Fourier transform for identifying projectile specimens by the line-scan imaging technique is proposed in this paper. This paper develops optical, photonic, and mechanical techniques to map the topography of the surfaces of forensic projectiles for the purpose of identification. Experiments discussed in this paper are performed on images acquired from 16 various weapons. Experimental results show that the proposed system can be used for firearm identification efficiently and precisely through digitizing and analyzing the fired projectiles specimens. PMID:17022254

  17. Developing Impact Marking Projectiles Using Triboluminescent Materials

    NASA Astrophysics Data System (ADS)

    Hollerman, William; Fontenot, Ross; Broussard, Brady; Goedeke, Shawn; Guidry, Corey

    2011-06-01

    In 1888, Wiedemann and Schmidt defined triboluminescence as the emission of light produced by mechanical action. In 1999, Sage and Geddes patented a design for a sensor capable of discerning the locations of impacts. Their design involved embedding a sensor inside a material coated with a triboluminescent crystal. Using this idea, the authors have been investigating the triboluminescent properties of several materials (like ZnS:Mn) for their possible use as the active element in ballistic projectiles. These new and improved rounds would be very useful because triboluminescence would mark the landing point of the projectile. This light would be ``cold'' in the sense it was not generated as a result of burning gunpowder or similar pyrotechnics. This light emission would also have a relatively short duration compared to other new projectiles, which generate long-term phosphorescence when two chemicals are mixed at impact (chemiluminescence). This presentation will give a status report in our efforts to develop practical impact marking ballistic projectiles using a triboluminescent charge.

  18. Octupole deformation in the ground states of even-even nuclei: A global analysis within the covariant density functional theory

    NASA Astrophysics Data System (ADS)

    Agbemava, S. E.; Afanasjev, A. V.; Ring, P.

    2016-04-01

    A systematic investigation of octupole-deformed nuclei is presented for even-even systems with Z ≤106 located between the two-proton and two-neutron driplines. For this study we use five most-up-to-date covariant energy density functionals of different types, with a nonlinear meson coupling, with density-dependent meson couplings, and with density-dependent zero-range interactions. Pairing correlations are treated within relativistic Hartree-Bogoliubov theory based on an effective separable particle-particle interaction of finite range. This allows us to assess theoretical uncertainties within the present covariant models for the prediction of physical observables relevant for octupole-deformed nuclei. In addition, a detailed comparison with the predictions of nonrelativistic models is performed. A new region of octupole deformation, centered around Z ˜98 ,N ˜196 is predicted for the first time. In terms of its size in the (Z ,N ) plane and the impact of octupole deformation on binding energies this region is similar to the best known region of octupole-deformed nuclei centered at Z ˜90 ,N ˜136 . For the later island of octupole-deformed nuclei, the calculations suggest substantial increase of its size as compared with available experimental data.

  19. High School Students' Understanding of Projectile Motion Concepts

    ERIC Educational Resources Information Center

    Dilber, Refik; Karaman, Ibrahim; Duzgun, Bahattin

    2009-01-01

    The aim of this study was to investigate the effectiveness of conceptual change-based instruction and traditionally designed physics instruction on students' understanding of projectile motion concepts. Misconceptions related to projectile motion concepts were determined by related literature on this subject. Accordingly, the Projectile Motion…

  20. High Spin States and Octupole Deformation in Neutron-Rich ^145,147La Nuclei

    NASA Astrophysics Data System (ADS)

    Zhu, S. J.; Hamilton, J. H.; Ramayya, A. V.; Babu, B. R. S.; Jones, E. F.; Kormicki, J.; Daniel, A. V.; Hwang, J. K.; Beyer, C. J.; Wang, M. G.; Long, G. L.; Li, M.; Zhu, L. Y.; Gan, C. Y.; Ma, W. C.; Cole, J. D.; Aryaeinejad, R.; Dardenne, Y. X.; Drigert, M. W.; Rasmussen, J. O.; Asztalos, S.; Lee, I. Y.; Macchiavelli, A. O.; Chu, S. Y.; Gregorich, K. E.; Mohar, M. F.; Stoyer, M. A.; Lougheed, R. W.; Moody, K. J.; Wild, J. F.; Prussin, S. G.

    1998-04-01

    High spin states in neutron-rich odd-Z nuclei ^145,147La have been investigated from the study of prompt γ- rays in spontaneous fission of ^252Cf by using γ-γ- and γ-γ-γ- coincidence techniques. Alternating parity bands are extended up to spins I=(41/2) and I=(43/2) in ^145La and ^147La, respectively. Strong E1 transitions between the negative and positive parity bands give evidence for stable octupole deformation. The new higher spin levels give evidence for rotational enhancement of the stability of the octupole deformation. These collective bands show competition and co-existence between symmetric and asymmetric shapes in ^145La. Band crossing was found around hbarω≈ 0.26 ~0.30 MeV in both nuclei and these backbends are related to the alignment of two i_13/2 neutron from cranked shell model calculations.

  1. High-power ion-cyclotron heating on the levitated octupole

    SciTech Connect

    Dexter, R.N.; Fortgang, C.M.; Prager, S.C.; Sprott, J.C.; Strait, E.J.; Twichell, J.C.

    1982-03-01

    Experiments are underway in the Wisconsin Levitated Toroidal Octupole to create hot, dense plasmas to facilitate the study of ..beta.. limits and related phenomena such as Pfirsch-Schlueter and bootstrap currents. The question of ballooning mode instability limits on ..beta.. = 8 ..pi..nk(T/sub i/+T/sub e/)/B/sup 2/ is of general importance for all toroidal systems, and ICRF heating should permit study of high ..beta.. plasmas with lower collisionality and smaller gyroradii than those of the high ..beta.. gun-injected plasmas currently under study in the Octupole. To these ends we are developing sources capable of delivering 4 MW to the plasma (1.5 MW coupled to the plasma to date, the rest under development).

  2. Mixed-symmetry octupole and hexadecapole excitations in N=52 isotones

    NASA Astrophysics Data System (ADS)

    Hennig, Andreas; Spieker, Mark; Werner, Volker; Ahn, Tan; Anagnostatou, Vassia; Cooper, Nathan; Derya, Vera; Elvers, Michael; Endres, Janis; Goddard, Phil; Heinz, Andreas; Hughes, Richard O.; Ilie, Gabriela; Mineva, Milena N.; Pickstone, Simon G.; Petkov, Pavel; Pietralla, Norbert; Radeck, Desirée; Ross, Tim J.; Savran, Deniz; Zilges, Andreas

    2015-05-01

    In addition to the well-established quadrupole mixed-symmetry states, octupole and hexadecapole excitations with mixed-symmetry character have been recently proposed for the N = 52 isotones 92Zr and 94Mo. We performed two inelastic proton-scattering experiments to study this kind of excitations in the heaviest stable N = 52 isotone 96Ru. From the combined experimental data of both experiments absolute transition strengths were extracted.

  3. Coherent quadrupole-octupole modes and split parity-doublet spectra in odd-A nuclei

    SciTech Connect

    Minkov, N.; Drenska, S.; Yotov, P.; Lalkovski, S.; Bonatsos, D.; Scheid, W.

    2007-09-15

    A collective model describing coherent quadrupole-octupole oscillations and rotations with a Coriolis coupling between the even-even core and the unpaired nucleon is applied to odd nuclei. The particle-core coupling provides a parity-doublet structure of the spectrum, whereas the quadrupole-octupole motion leads to a splitting of the doublet energy levels. The formalism successfully reproduces the split parity-doublet spectra and the attendant B(E1) and B(E2) transition probabilities in a wide range of odd-A nuclei. It provides estimations for the influence of the Coriolis interaction on the collective motion and subsequently for the value of angular momentum projection K on which the spectrum is built. The analysis of the energy splitting and B(E1) transition probabilities between opposite parity counterparts suggests degenerate doublet structures at high angular momenta. The study provides information about the evolution of quadrupole-octupole collectivity in odd-mass nuclei.

  4. Spectroscopy of quadrupole and octupole states in rare-earth nuclei from a Gogny force

    NASA Astrophysics Data System (ADS)

    Nomura, K.; Rodríguez-Guzmán, R.; Robledo, L. M.

    2015-07-01

    Collective quadrupole and octupole states are described in a series of Sm and Gd isotopes within the framework of the interacting boson model (IBM), whose Hamiltonian parameters are deduced from mean-field calculations with the Gogny energy density functional. The link between both frameworks is the (β2β3 ) potential energy surface computed within the Hartree-Fock-Bogoliubov framework in the case of the Gogny force. The diagonalization of the IBM Hamiltonian provides excitation energies and transition strengths of an assorted set of states including both positive- and negative-parity states. The resultant spectroscopic properties are compared with the available experimental data and also with the results of the configuration mixing calculations with the Gogny force within the generator coordinate method (GCM). The structure of excited 0+ states and its connection with double-octupole phonons is also addressed. The model is shown to describe the empirical trend of the low-energy quadrupole and octupole collective structure fairly well and turns out to be consistent with GCM results obtained with the Gogny force.

  5. Initiation of Gaseous Detonation by Conical Projectiles

    NASA Astrophysics Data System (ADS)

    Verreault, Jimmy

    Initiation and stabilization of detonation by hypersonic conical projectiles launched into combustible gas mixtures is investigated. This phenomenon must be understood for the design and optimization of specific hypersonic propulsion devices, such as the oblique detonation wave engine and the ram accelerator. The criteria for detonation initiation by a projectile is also related to fundamental aspects of detonation research, such as the requirement for direct initiation of a detonation by a blast wave. Experimental results of this problem also offer useful references for validation of numerical and theoretical modeling. Projectiles with cone half angles varying from 15° to 60° were launched into stoichiometric mixtures of hydrogen/oxygen with 70% argon dilution at initial pressures between 10 and 200 kPa. The projectiles were launched from a combustion-driven gas gun at velocities up to 2.2 km/s (corresponding to 133% of the Chapman Jouguet velocity). Pictures of the flowfields generated by the projectiles were taken via Schlieren photography. Five combustion regimes were observed about the projectile ranging from prompt and delayed oblique detonation wave formation, combustion instabilities, a wave splitting, and an inert shock wave. Two types of transition from the prompt oblique detonation wave regime to the inert shock regime were observed. The first (the delayed oblique detonation wave regime) showed an inert shock attached to the tip of the projectile followed by a sharp kink at the onset of an oblique detonation wave; this regime occurred by decreasing the cone angle at high mixture pressures. The second (the combustion instabilities regime) exhibited large density gradients due to combustion ignition and quenching phenomena; this regime occurred by decreasing the mixture pressure at large cone angles. A number of theoretical models were considered to predict critical conditions for the initiation of oblique detonations. The Lee-Vasiljev model agreed

  6. Method of and apparatus for accelerating a projectile

    DOEpatents

    Goldstein, Yeshayahu S. A.; Tidman, Derek A.

    1986-01-01

    A projectile is accelerated along a confined path by supplying a pulsed high pressure, high velocity plasma jet to the rear of the projectile as the projectile traverses the path. The jet enters the confined path at a non-zero angle relative to the projectile path. The pulse is derived from a dielectric capillary tube having an interior wall from which plasma forming material is ablated in response to a discharge voltage. The projectile can be accelerated in response to the kinetic energy in the plasma jet or in response to a pressure increase of gases in the confined path resulting from the heat added to the gases by the plasma.

  7. Apparatus and method for the acceleration of projectiles to hypervelocities

    DOEpatents

    Hertzberg, Abraham; Bruckner, Adam P.; Bogdanoff, David W.

    1990-01-01

    A projectile is initially accelerated to a supersonic velocity and then injected into a launch tube filled with a gaseous propellant. The projectile outer surface and launch tube inner surface form a ramjet having a diffuser, a combustion chamber and a nozzle. A catalytic coated flame holder projecting from the projectile ignites the gaseous propellant in the combustion chamber thereby accelerating the projectile in a subsonic combustion mode zone. The projectile then enters an overdriven detonation wave launch tube zone wherein further projectile acceleration is achieved by a formed, controlled overdriven detonation wave capable of igniting the gaseous propellant in the combustion chamber. Ultrahigh velocity projectile accelerations are achieved in a launch tube layered detonation zone having an inner sleeve filled with hydrogen gas. An explosive, which is disposed in the annular zone between the inner sleeve and the launch tube, explodes responsive to an impinging shock wave emanating from the diffuser of the accelerating projectile thereby forcing the inner sleeve inward and imparting an acceleration to the projectile. For applications wherein solid or liquid high explosives are employed, the explosion thereof forces the inner sleeve inward, forming a throat behind the projectile. This throat chokes flow behind, thereby imparting an acceleration to the projectile.

  8. Octupole correlations in low-lying states of 150Nd and 150Sm and their impact on neutrinoless double-β decay

    NASA Astrophysics Data System (ADS)

    Yao, J. M.; Engel, J.

    2016-07-01

    We present a generator-coordinate calculation, based on a relativistic energy-density functional, of the low-lying spectra in the isotopes 150Nd and 150Sm and of the nuclear matrix element that governs the neutrinoless double-β decay of the first isotope to the second. We carefully examine the impact of octupole correlations on both nuclear structure and the double-β decay matrix element. Octupole correlations turn out to reduce quadrupole collectivity in both nuclei. Shape fluctuations, however, dilute the effects of octupole deformation on the double-β decay matrix element, so that the overall octupole-induced quenching is only about 7 % .

  9. Study of critical ricochet angle for conical nose shape projectiles

    NASA Astrophysics Data System (ADS)

    Murali, Vijayalakshmi; Law, Manish G.; Naik, Smita D.

    2012-09-01

    The purpose of this research is to formulate a generic analytical model to assess the phenomena of water ricochet for a conical nose shaped projectile. A theoretical model is analyzed to study the critical angle of conical nose shaped projectile entering in water and is extended for different mediums as normal sand and mercury. Numerical Simulation has been carried out to find the effect of tip angle of the conical nose shaped projectile on the critical angle. Critical angle is defined as that angle of impact of the projectile above which ricochet will occur. This angle is obtained by balancing the momentums acting on the projectile at the time of impact on the basis of Newtonian theory. Major factors affecting critical angle are impact velocity, impact angle, density of the projectile and the target. An attempt has been made to study the effect of longitudinal spin of the projectile on the critical angle.

  10. Shallow-angle water entry of ballistic projectiles

    NASA Astrophysics Data System (ADS)

    Truscott, Tadd T.; Gomez, Jason T.; Beal, David N.; Techet, Alexandra H.

    2008-11-01

    The water-entry of ballistic projectiles is investigated using high-speed digital imaging. Projectiles enter the water at shallow angles to the free surface, 5^o-15^o, without ricochet at Mach numbers between 0.3 and 2.0. Projectile dynamics, critical entry angle, and cavity growth are discussed. Geometric modifications to a projectile allow it to travel large distances underwater assuming a sufficiently large air-cavity is formed after impact, which dramatically decreases drag on the projectile. Results show that successful water-entry occurs for projectiles with modified tip geometries at Mach numbers ranging from 0.3 to 2; these projectile modifications include tip geometry and material properties. A theoretical cavity model compares well with the experimental data and will be discussed for a range of experimental conditions.

  11. Projectile Density Effects on Shield Performance

    NASA Technical Reports Server (NTRS)

    Christiansen, Eric L.; Lear, Dana; Lyons, Frankel; Davis, Alan

    2009-01-01

    In the past, the orbital debris environment was modeled as consisting entirely of aluminum particles. As a consequence, most of the impact test database on spacecraft micro-meteoroid and orbital debris (MMOD) shields, and the resulting ballistic limit equations used to predict shielding performance, has been based on using aluminum projectiles. Recently, data has been collected from returned spacecraft materials and other sources that indicate higher and lower density components of orbital debris also exist. New orbital debris environment models such as ORDEM2008 provide predictions of the fraction of orbital debris in various density bins (high = 7.9 g/cu cm, medium = 2.8 g/cu cm, and low = 0.9-1.1 g/cu cm). This paper describes impact tests to assess the effects of projectile density on the performance capabilities of typical MMOD shields. Updates to shield ballistic limit equations are provided based on results of tests and analysis.

  12. The aerodynamics of some guided projectiles

    NASA Technical Reports Server (NTRS)

    Spearman, M. L.

    1984-01-01

    Some characteristic projectile shapes are considered with various added components intended to provide lift, stability, and control. The intent of the additions is to provide some means for altering the normal ballistic flight path of a projectile for various purposes such as: achieving greater accuracy at the impact point, selecting alternate impact points, extending range, improved evasion, and so on. The configurations presented illustrate the effects of a flare, wings, and tails for providing stability and lift, and the effects of aft-tails, a close-coupled flap, and all-moving forward wings for control. The relative merits of the various configurations, all of which provided for flight path alterations, are discussed.

  13. The aerodynamics of some guided projectiles

    NASA Technical Reports Server (NTRS)

    Spearman, M. L.

    1984-01-01

    Some characteristic projectile shapes are considered with various added components intended to provide lift, stability, and control. The intent of the additions is to provide some means for altering the normal ballistic flight path of a projectile for various purposes such as: achieving greater accuracy at the impact point, selecting alternate impact points, extending range, improved evasion, and so on. The configurations presented illustrate the effects of a flare, wings, and tails for providing stability and lift, and the effects of aft-tails, a close-coupled flap, and all-moving forward wings for control. The relative merits of the various configurations, all of which provided for flight path alterations are discussed.

  14. An Inexpensive Mechanical Model for Projectile Motion

    NASA Astrophysics Data System (ADS)

    Kagan, David

    2011-05-01

    As experienced physicists, we see the beauty and simplicity of projectile motion. It is merely the superposition of uniform linear motion along the direction of the initial velocity vector and the downward motion due to the constant acceleration of gravity. We see the kinematic equations as just the mathematical machinery to perform the calculations. What do our students see? Likely, most see no deeper than the operational understanding needed to use the kinematic equations. Described below is a device (shown in Fig. 1) that illustrates the physicist's view of projectile motion. It can be used as a classroom demonstration or as a project for your students, and it costs less than three dollars to make.

  15. Modeling projectile impact onto prestressed ceramic targets

    NASA Astrophysics Data System (ADS)

    Holmquist, T. J.; Johnson, G. R.

    2003-09-01

    This work presents computed results for the responses of ceramic targets, with and without prestress, subjected to projectile impact. Also presented is a computational technique to include prestress. Ceramic materials have been considered for armor applications for many years because of their high strength and low density. Many researchers have demonstrated that providing confinement enhances the ballistic performance of ceramic targets. More recently, prestressing the ceramic is being considered as an additional enhancement technique. This work investigates the effect of prestressing the ceramic for both thin and thick target configurations subjected to projectile impact. In all cases the targets with ceramic prestress provided enhanced ballistic performance. The computed results indicate that prestressed ceramic reduces and/or delays failure, resulting in improved ceramic performance and ballistic efficiency.

  16. Energy loss of hydrogen projectiles in gases

    SciTech Connect

    Schiefermueller, A.; Golser, R.; Stohl, R.; Semrad, D. )

    1993-12-01

    The stopping cross sections of H[sub 2], D[sub 2], He, and Ne for hydrogen projectiles in the energy range 3--20 keV per nucleon have been measured by time of flight. We compare our experimental result to the sum of the individual contributions due to excitation and ionization of the target and of the projectile, respectively, and due to charge exchange, using published cross-section data. Satisfactory agreement is found only for the He target and only at moderate projectile velocities, whereas for H[sub 2] and D[sub 2] the calculated values are about 30% too low. A Monte Carlo program allows us to simulate the measured time-of-flight spectra and to explain minor trends in the experimental data: for increased Ne gas pressure, an increased specific energy loss has been found that can be traced to different regions of impact parameters selected in our transmission geometry. This also explains, in part, the increased specific energy loss for deuterons compared to protons of equal velocity that is most evident for Ne. In contrast, a decrease of the specific energy loss with increasing pressure for He may be explained by impurities in the target gas. If we correct for the effect of impurities, the stopping cross section of He at 4 keV per nucleon is slightly smaller (0.60[times]10[sup [minus]15] eV cm[sup 2]) than published earlier (0.72[times]10[sup [minus]15] eV cm[sup 2]) and depends on the 3.8th power of projectile velocity.

  17. Fragmentation of hypervelocity aluminum projectiles on fabrics

    NASA Astrophysics Data System (ADS)

    Rudolph, Martin; Schäfer, Frank; Destefanis, Roberto; Faraud, Moreno; Lambert, Michel

    2012-07-01

    This paper presents work performed for a study investigating the ability of different flexible materials to induce fragmentation of a hypervelocity projectile. Samples were chosen to represent a wide range of industrially available types of flexible materials like ceramic, aramid and carbon fabrics as well as a thin metallic mesh. Impact conditions and areal density were kept constant for all targets. Betacloth and multi-layer insulation (B-MLI) are mounted onto the targets to account for thermal system engineering requirements. All tests were performed using the Space light-gas gun facility (SLGG) of the Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut, EMI. Projectiles were aluminum spheres with 5 mm diameter impacting at approximately 6.3 km/s. Fragmentation was evaluated using a witness plate behind the target. An aramid and a ceramic fabric lead the ranking of fabrics with the best projectile fragmentation and debris cloud dispersion performance. A comparison with an equal-density rigid aluminum plate is presented. The work presented can be applied to optimize the micrometeoroid and space debris (MM/SD) shielding structure of inflatable modules.

  18. Improvements to a model of projectile fragmentation

    NASA Astrophysics Data System (ADS)

    Mallik, S.; Chaudhuri, G.; Das Gupta, S.

    2011-11-01

    In a recent paper [Phys. Rev. CPRVCAN0556-281310.1103/PhysRevC.83.044612 83, 044612 (2011)] we proposed a model for calculating cross sections of various reaction products which arise from disintegration of projectile-like fragments resulting from heavy-ion collisions at intermediate or higher energy. The model has three parts: (1) abrasion, (2) disintegration of the hot abraded projectile-like fragment (PLF) into nucleons and primary composites using a model of equilibrium statistical mechanics, and (3) possible evaporation of hot primary composites. It was assumed that the PLF resulting from abrasion has one temperature T. Data suggested that, while just one value of T seemed adequate for most cross-section calculations, a single value failed when dealing with very peripheral collisions. We have now introduced a variable T=T(b) where b is the impact parameter of the collision. We argue that there are data which not only show that T must be a function of b but, in addition, also point to an approximate value of T for a given b. We propose a very simple formula: T(b)=D0+D1[As(b)/A0] where As(b) is the mass of the abraded PLF and A0 is the mass of the projectile; D0 and D1 are constants. Using this model we compute cross sections for several collisions and compare with data.

  19. A hypervelocity projectile launcher for well perforation

    SciTech Connect

    Albright, J.N.; Fugelso, L.E.; Lagner, G.C.; Burns, K.L.

    1989-01-01

    Current oil well perforation techniques use low- to medium-velocity gun launchers for completing wells in soft rock. Shaped-charge jets are normally used in harder, more competent rock. A device to create a much higher velocity projectile was designed. This launcher will provide an alternative technique to be used when the conventional devices do not yield the maximum well performance. It is an adaptation of the axial cavity in a high explosive (HE) annulus design, with the axial cavity being filled with a low density foam material. Two configurations were tested; both had an HE annulus filled with organic foam, one had a projectile. Comparison of the two shots was made. A time sequence of Image Intensifier Camera photographs and sequential, orthogonal flash x-ray radiographs provided information on the propagation of the foam fragments, the first shock wave disturbance, the projectile motion and deformation, and the direct shock wave transmission from the main HE charge. DYNA2D calculations were made to assist in the experimental interpretation. 25 refs., 9 figs.

  20. Forensic and clinical issues in the use of frangible projectile.

    PubMed

    Komenda, Jan; Hejna, Petr; Rydlo, Martin; Novák, Miroslav; Krajsa, Jan; Racek, František; Rejtar, Pavel; Jedlička, Luděk

    2013-08-01

    Frangible projectiles for firearms, which break apart on impact, are mainly used by law enforcement agencies for training purposes, but can also be used for police interventions. Apart from the usual absence of lead in the projectiles, the main advantage of using frangible projectiles is the reduced risk of ricochet after impact with a hard target. This article describes the design and function of frangible projectiles, and describes gunshot wounds caused by ultra-frangible projectiles which fragment after penetration of soft tissues. Shooting experiments performed by the authors confirmed that differences in the geometry and technology of frangible projectiles can significantly modify their wounding effects. Some frangible projectiles have minimal wounding effects because they remain compact after penetration of soft tissues, comparable to standard fully jacketed projectiles. However, a number of ultra-frangible projectiles disintegrate into very small fragments after impact with a soft tissue substitute. In shooting experiments, we found that the terminal behavior of selected ultra-frangible projectiles was similar in a block of ballistic gel and the soft tissues of the hind leg of a pig, except that the degree of disintegration was less in the gel. PMID:23910864

  1. On the forces produced by oblique projectile impact

    SciTech Connect

    Yew, C.H.

    1995-12-31

    A mathematical model for calculating the force produced by projectile impact on terrestrial target was developed based on assumptions that (1) the projectile was rigid, and (2) the target material near the nose section was displaced normally to the nose surface by the penetrating projectile. The assumption suggested that the crater or tunnel produced by the penetrating projectile was similar to that produced by a series of dynamic spherical cavity expansions initiated at the nose tip, and the growth rate of cavities was restricted by the nose shape of the projectile and its penetrating velocity vector. The model allowed the calculation of pressure against the penetrating projectile by taking the inertia and the resistant pressure of the moving soil into consideration. The effect of projectile obliquity on pressure distribution on the nose section of projectile could also be calculated by relating the angle of attack and the angle of incidence to the rate of local radius change of the expanding cavity. Using this model, the time history of force vector exerted on the projectile as well as the corresponding trajectory of penetration were calculated. For a small angle of incidence, the calculated axial and lateral forces exerted on the nose of projectile showed a reasonable agreement with those measured from reverse ballistic impact tests. It was demonstrated that the magnitude of forces depended upon the impact velocity, the shape of projectile`s nose section, and the relative density between the projectile and the target material. There were no quantitative measurement of forces when the angle of incidence was large i.e., a shallow impact. For this case, the calculated forces were compared and discussed with the results from similitude analysis.

  2. Numerical simulations of gun-launched kinetic energy projectiles subjected to asymmetric projectile base pressure

    SciTech Connect

    Rabern, D.A.

    1991-01-01

    Three-dimensional numerical simulations were performed to determine the effect of an asymmetric base pressure on kinetic energy projectiles during launch. A matrix of simulations was performed in two separate launch environments. One launch environment represented a severe lateral load environment, while the other represented a nonsevere lateral load environment based on the gun tube straightness. The orientation of the asymmetric pressure field, its duration, the projectile's initial position, and the tube straightness were altered to determine the effects of each parameter. The pressure asymmetry translates down the launch tube to exit parameters and is washed out by tube profile. Results from the matrix of simulations are presented.

  3. Railgun using plasma initiation separated from the projectile

    SciTech Connect

    Katsuki, S.; Akiyama, H.; Yamada, T.; Eguchi, N.; Maeda, S.; Sato, K.N.

    1993-12-01

    Preacceleration of a projectile is quite important to reduce the erosion of the bore surface in a railgun. Gas guns, electrothermal guns and other railguns have been used to preaccelerate the projectile. Here, the new method using Plasma Initiation Separated from the Projectile (PISP method) is proposed, and its effectiveness is confirmed experimentally. A thin copper is placed near the edge of the railgun, which explodes and forms a plasma that has a fast flow velocity due to the Lorentz force. This fast flowing plasma collides with the projectile which obtains an initial velocity mainly by the momentum transfer. Since the current increases while only the plasma is accelerated, the driving force of the projectile just after the collision of the plasma with the projectile is large. In other words, the PISP method works as an inductive energy storage circuit with an opening switch.

  4. Design and fabrication of projectiles for round bore railguns

    SciTech Connect

    Susoeff, A.R.; Hawke, R.S.

    1985-03-07

    A hypervelocity railgun system which operates in a vacuum and uses a gas gun injector to pre-accelerate the projectiles required that the projectile seal operate over wide pressure and velocity ranges. In our case, the helium gas gun injector operated at up to 35 MPa (5 ksi) while the railgun, using a plasma arc armature, operated at up to 150 MPa (22 ksi). In addition to gas and arc sealing, it was necessary that a metal fuse be attached to the rear of the projectile in order to electrically commutate the rails upon entry to the railgun. This paper discusses procedures and techniques in the design and fabrication of projectiles for a round bore railgun. It is divided into three sections: (1) machining the projectile; (2) fuse fabrication; and (3) assembly of the projectile/fuse package.

  5. Hign-speed penetration of projectile with cavitator into sand

    NASA Astrophysics Data System (ADS)

    Daurskikh, Anna; Veldanov, Vladislav

    2011-06-01

    Cavitators are used in underwater projectiles design to form a cavern in which projectile could move with no or significantly reduced drag. An investigation of possible application of this structural element for penetration into porous media was conducted. High-speed impact of a conical-shaped head projectile with cavitator was studied in terms of its influence on penetration capacity and projectile stability in sand for impact velocity about 1500 m/s. Cavitators were manufactured of steel with different strength moduli, and thus two penetration regimes (with eroding/non-eroding cavitator) were compared. Numerical simulations showing wave propagation in target and projectile were performed in AUTODYN with Johnson-Cook model for projectile and granular model for sand.

  6. Application of the triaxial quadrupole-octupole rotor to the ground and negative-parity levels of actinide nuclei

    NASA Astrophysics Data System (ADS)

    Nadirbekov, M. S.; Minkov, N.; Strecker, M.; Scheid, W.

    2016-03-01

    In this work, we examine the possibility to describe yrast positive- and negative-parity excitations of deformed even-even nuclei through a collective rotation model in which the nuclear surface is characterized by triaxial quadrupole and octupole deformations. The nuclear moments of inertia are expressed as sums of quadrupole and octupole parts. By assuming an adiabatic separation of rotation and vibration degrees of freedom, we suppose that the structure of the positive- and negative-parity bands may be determined by the triaxial-rigid-rotor motion of the nucleus. By diagonalizing the Hamiltonian in a symmetrized rotor basis with embedded parity, we obtain a model description for the yrast positive- and negative-parity bands in several actinide nuclei. We show that the energy displacement between the opposite-parity sequences can be explained as the result of the quadrupole-octupole triaxiality.

  7. Design and testing of high-pressure railguns and projectiles

    SciTech Connect

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

    1984-03-01

    The results of high-pressure tests of four railgun designs and four projectile types are presented. All tests were conducted at the Los Alamos explosive magnetic-flux compression facility in Ancho Canyon. The data suggest that the high-strength projectiles have lower resistance to acceleration than the lowstrength projectiles, which expand against the bore during acceleration. The railguns were powered by explosive magneticflux compression generators. Calculations to predict railgun and power supply performance were performed by Kerrisk.

  8. Design and testing of high-pressure railguns and projectiles

    SciTech Connect

    Peterson, D.R.; Fowler, C.M.; Cummings, C.E.; Kerrisk, J.F.; Parker, J.V.; Marsh, S.P.; Adams, D.F.

    1983-01-01

    The results of high-pressure tests of four railgun designs and four projectile types are presented. All tests were conducted at the Los Alamos explosive magnetic-flux compression facility in Ancho Canyon. The data suggest that the high-strength projectiles have lower resistance to acceleration than the low-strength projectiles, which expand against the bore during acceleration. The railguns were powered by explosive magnetic-flux compression generators. Calculations to predict railgun and power supply performance were performed.

  9. Flight dynamics of a spinning projectile descending on a parachute

    SciTech Connect

    Benedetti, G.A.

    1989-02-01

    During the past twenty years Sandia National Laboratories and the US Army have vertically gun launched numerous 155mm and eight-inch diameter flight test projectiles. These projectiles are subsequently recovered using an on-board parachute recovery system which is attached to the forward case structure of the projectile. There have been at least five attempts to describe, through analytical and numerical simulations, the translational and rotational motions of a spinning projectile descending on a parachute. However, none of these investigations have correctly described the large nutational motion of the projectile since all of them overlooked the fundamental mechanism which causes these angular motions. Numerical simulations as well as a closed form analytical solution show conclusively that the Magnus moment is responsible for the large nutational motion of the projectile. That is, when the center of pressure for the Magnus force is aft of the center of mass for the projectile, the Magnus moment causes an unstable (or large) nutational motion which always tends to turn the spinning projectile upside down while it is descending on the parachute. Conversely, when the center of mass for the projectile is aft of the center of pressure for the Magnus force, the Magnus moment stabilizes the nutational motion tending to always point the base of the spinning projectile down. The results of this work are utilized to render projectile parachute recovery systems more reliable and to explain what initially may appear to be strange gyrodynamic behavior of a spinning projectile descending on a parachute. 14 refs., 20 figs.

  10. A novel antiproton radial diagnostic based on octupole induced ballistic loss

    SciTech Connect

    Andresen, G. B.; Bowe, P. D.; Hangst, J. S.; Bertsche, W.; Butler, E.; Charlton, M.; Humphries, A. J.; Jenkins, M. J.; Joergensen, L. V.; Madsen, N.; Werf, D. P. van der; Bray, C. C.; Chapman, S.; Fajans, J.; Povilus, A.; Wurtele, J. S.; Cesar, C. L.; Lambo, R.; Silveira, D. M.; Fujiwara, M. C.

    2008-03-15

    We report results from a novel diagnostic that probes the outer radial profile of trapped antiproton clouds. The diagnostic allows us to determine the profile by monitoring the time history of antiproton losses that occur as an octupole field in the antiproton confinement region is increased. We show several examples of how this diagnostic helps us to understand the radial dynamics of antiprotons in normal and nested Penning-Malmberg traps. Better understanding of these dynamics may aid current attempts to trap antihydrogen atoms.

  11. Crystallization of ion clouds in octupole traps: Structural transitions, core melting, and scaling laws

    SciTech Connect

    Calvo, F.; Champenois, C.; Yurtsever, E.

    2009-12-15

    The stable structures and melting properties of ion clouds in isotropic octupole traps are investigated using a combination of semianalytical and numerical models, with a particular emphasis at finite-size scaling effects. Small-size clouds are found to be hollow and arranged in shells corresponding approximately to the solutions of the Thomson problem. The shell structure is lost in clusters containing more than a few thousands of ions, the inner parts of the cloud becoming soft and amorphous. While melting is triggered in the core shells, the melting temperature follows the rule expected for three-dimensional dense particles, with a depression scaling linearly with the inverse radius.

  12. Approximate analysis of balloting motion of railgun projectiles. Technical report

    SciTech Connect

    Chu, S.H.

    1991-07-01

    This is the final of three reports dealing with the in-bore balloting motion of a projectile fired from an electromagnetic railgun. Knowledge of projectile in-bore motion is important to its design and the design of the railgun. It is a complicated problem since many parameters are involved and it is not easy to determine the interacting relationships between them. To make the problem easier to understand it was analyzed on several levels. Beginning from the basic simple model which computed only the axial motion, more complicated models were introduced in upper levels that included the more significant lateral forces and gun tube vibration effects. This report deals with the approximate analysis of balloting motion. This model considers the effects of the propulsion force, the friction force of the projectile package (projectile and armature), air resistance, gravity, the elastic forces, and the projectile/barrel clearance. To simplify the modeling, a plane motion configuration is assumed. Though the projectile is moving with a varying yaw angle, the axes of the barrel and the projectile package, and the projectile center of gravity are always considered in a plane containing the centerlines of the rails. Equations of motion are derived and solved. A sample computation is performed and the results plotted to give a clearer understanding of projectile in-bore motion.

  13. Continuous measurements of in-bore projectile velocity

    SciTech Connect

    Asay, J.R.; Konrad, C.H.; Hall, C.A.; Shahinpoor, M.; Hickman, R.

    1988-01-01

    The application of velocity interferometry to the continuous measurement of in-bore projectile velocity in a small-bore three-stage railgun is described. These measurements are useful for determining projectile acceleration and for evaluating gun performance. The launcher employed in these studies consists of a two-stage light gas gun used to inject projectiles into a railgun for additional acceleration. Results obtained for projectile velocities to 7.4 km/s with the two-stage injector are reported and potential improvements for railgun applications are discussed. 12 refs., 7 figs.

  14. Continuous measurements of in-bore projectile velocity

    SciTech Connect

    Asay, J.R.; Konrad, C.H.; Hall, C.A. ); Shahinpoor, M. . Dept. of Mechanical Engineering); Hickman, R. )

    1989-01-01

    The application of velocity interferometry to the continuous measurement of in-bore projectile velocity in a small-bore three-stage railgun is described. These measurements are useful for determining projectile acceleration and for evaluating gun performance. The launcher employed in these studies consists of a two-stage light gas gun used to inject projectiles into a railgun for additional acceleration. Results obtained for projectile velocities to 7.4 km/s with the two-stage injector are reported and potential improvements for railgun applications are discussed.

  15. Projectile development for railguns using hypervelocity preacceleration. Revision 1

    SciTech Connect

    Susoeff, A.R.; Hawke, R.S.; Ang, J.A.; Asay, J.R.; Hall, C.A.; Konrad, C.H.; Sauve, G.L.; Hickman, R.J.

    1992-03-20

    The STARFIRE Project is a joint Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories (SNL) effort to achieve hypervelocity projectile launches up to 15 km/s. The apparatus used to achieve this goal is a three stage acceleration system made up of a two-stage light-gas gun (2SLGG) coupled to a railgun. The 2SLGG is used as a preaccelerator capable of injecting 2 gram projectiles at velocities of 6 km/s or more. Projectiles used in this environment are subject to many conditions. Some of these which effect projectile design include: acceleration loading, structural response, barrel condition and alignment. Development of a projectile to satisfy the programmatic requirements is underway. This report covers the evolution of design and fabrication for railgun projectiles from previous experiment at LLNL to the replenished plasma armature and projectile now used on STARFIRE. Projectile design, development and fabrication methods which use off-the-shelf materials and standard techniques to meet the operational criteria of the experimental program are discussed in this paper. Initial work involving the design and fabrication of skirted projectiles, which are expected to further reduce interaction phenomena between the plasma armature and railgun barrel, is also described.

  16. Penetration into limestone targets with ogive-nose steel projectiles

    SciTech Connect

    Frew, D.J.; Green, M.L.; Forrestal, M.J.; Hanchak, S.J.

    1996-12-01

    We conducted depth of penetration experiments into limestone targets with 3.0 caliber-radius-head, 4340 Rc 45 steel projectiles. Powder guns launched two projectiles with length-to-diameter ratios of ten to striking velocities between 0.4 and 1.5 km/s. Projectiles had diameters and masses of 12.7 mm, 0. 117 kg and 25.4 mm, 0.610 kg. Based on data sets with these two projectile scales, we proposed an empirical penetration equation that described the target by its density and an empirical strength constant determined from penetration depth versus striking velocity data.

  17. Prediction of projectile ricochet behavior after water impact.

    PubMed

    Baillargeon, Yves; Bergeron, Guy

    2012-11-01

    Although not very common, forensic investigation related to projectile ricochet on water can be required when undesirable collateral damage occurs. Predicting the ricochet behavior of a projectile is challenging owing to numerous parameters involved: impact velocity, incident angle, projectile stability, angular velocity, etc. Ricochet characteristics of different projectiles (K50 BMG, 0.5-cal Ball M2, 0.5-cal AP-T C44, 7.62-mm Ball C21, and 5.56-mm Ball C77) were studied in a pool. The results are presented to assess projectile velocity after ricochet, ricochet angle, and projectile azimuth angle based on impact velocity or incident angle for each projectile type. The azimuth ranges show the highest variability at low postricochet velocity. The critical ricochet angles were ranging from 15 to 30°. The average ricochet angles for all projectiles were pretty close for all projectiles at 2.5 and 10° incident angles for the range of velocities studied. PMID:22536929

  18. Design and testing of high-pressure railguns and projectiles

    NASA Technical Reports Server (NTRS)

    Peterson, D. R.; Fowler, C. M.; Cummings, C. E.; Kerrisk, J. F.; Parker, J. V.; Marsh, S. P.; Adams, D. F.

    1984-01-01

    Attention is given to the results of high-pressure tests involving four railgun designs and four projectile types. Explosive magnetic-flux compression generators were employed to power the railguns. On the basis of the experimental data, it appears that the high-strength projectiles have lower resistance to acceleration than low-strength projectiles, which expand against the bore during acceleration. While confined in the bore, polycarbonate projectiles can be subjected to pressures as high as 1.3 GPa without shattering. In multishot railguns, it is important to prevent an accumulation of sooty material from the plasma armature in railgun seams.

  19. Design and testing of high-pressure railguns and projectiles

    NASA Astrophysics Data System (ADS)

    Peterson, D. R.; Fowler, C. M.; Cummings, C. E.; Kerrisk, J. F.; Parker, J. V.; Marsh, S. P.; Adams, D. F.

    1984-03-01

    Attention is given to the results of high-pressure tests involving four railgun designs and four projectile types. Explosive magnetic-flux compression generators were employed to power the railguns. On the basis of the experimental data, it appears that the high-strength projectiles have lower resistance to acceleration than low-strength projectiles, which expand against the bore during acceleration. While confined in the bore, polycarbonate projectiles can be subjected to pressures as high as 1.3 GPa without shattering. In multishot railguns, it is important to prevent an accumulation of sooty material from the plasma armature in railgun seams.

  20. Electric rail gun projectile acceleration to high velocity

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  1. Microcraters formed in glass by low density projectiles

    NASA Technical Reports Server (NTRS)

    Mandeville, J.-C.; Vedder, J. F.

    1971-01-01

    Microcraters were produced in soda-lime glass by the impact of low density projectiles of polystyrene with masses between 0.7 and 62 picograms and velocities between 2 and 14 kilometers per second. The morphology of the craters depends on the velocity and angle of incidence of the projectiles. The transitions in morphology of the craters formed by polystyrene spheres occur at higher velocities than they do for more dense projectiles. For oblique impact, the craters are elongated and shallow with the spallation threshold occuring at higher velocity. For normal incidence, the total displaced mass of the target material per unit of projectile kinetic energy increases slowly with the energy.

  2. Penetration of projectiles into granular targets

    NASA Astrophysics Data System (ADS)

    Ruiz-Suárez, J. C.

    2013-06-01

    Energetic collisions of subatomic particles with fixed or moving targets have been very valuable to penetrate into the mysteries of nature. But the mysteries are quite intriguing when projectiles and targets are macroscopically immense. We know that countless debris wandering in space impacted (and still do) large asteroids, moons and planets; and that millions of craters on their surfaces are traces of such collisions. By classifying and studying the morphology of such craters, geologists and astrophysicists obtain important clues to understand the origin and evolution of the Solar System. This review surveys knowledge about crater phenomena in the planetary science context, avoiding detailed descriptions already found in excellent papers on the subject. Then, it examines the most important results reported in the literature related to impact and penetration phenomena in granular targets obtained by doing simple experiments. The main goal is to discern whether both schools, one that takes into account the right ingredients (planetary bodies and very high energies) but cannot physically reproduce the collisions, and the other that easily carries out the collisions but uses laboratory ingredients (small projectiles and low energies), can arrive at a synergistic intersection point.

  3. Powder metallurgy process for manufacturing core projectile

    NASA Astrophysics Data System (ADS)

    Akbar, Taufik; Setyowati, Vuri Ayu; Widyastuti

    2013-09-01

    Bullets are part of the defense equipment which the development is very rapid. There are a variety of forms but the bullet Lead is a metal that has always been used for applications projectiles. Lead core constituent materials are combined with antimony. In this research will be conducted by making the material for the core projectile with Tin Lead. The addition of Tin will increase the stiffness of Lead which is soft in nature. The Lead Tin composition variation was given in 10% weight of Sn. The manufacturing process using powder metallurgy using temperature and holding time variations of sintering at 100, 150, and 200°C for 1,2, and 3 hours. XRD samples will be tested to determine the form and phase morphology was observed using SEM-EDX. These results revealed that Pb-10%wtSn Composite which is sintered in temperature 200°C for 3 hours has the greatest density, 10.695 g/cm3 as well as the smallest porosity, 2.2%. In agreement with theoretical analysis that increasing higher temperature and longer holding time give decrease in porosity level due to activation energy which further promotes grain growth. Moreover, there is no intermetallic phase formation as well as no oxide found on composites.

  4. Jetting during vertical impacts of spherical projectiles

    NASA Astrophysics Data System (ADS)

    Johnson, B. C.; Bowling, T. J.; Melosh, H. J.

    2014-08-01

    The extreme pressures reached during jetting, a process by which material is squirted out from the contact point of two colliding objects, causes melting and vaporization at low impact velocities. Jetting is a major source of melting in shocked porous material, a potential source of tektites, a possible origin of chondrules, and even a conceivable origin of the Moon. Here, in an attempt to quantify the importance of jetting, we present numerical simulation of jetting during the vertical impacts of spherical projectiles on both flat and curved targets. We find that impacts on curved targets result in more jetted material but that higher impact velocities result in less jetted material. For an aluminum impactor striking a flat Al target at 2 km/s we find that 3.4% of a projectile mass is jetted while 8.3% is jetted for an impact between two equal sized Al spheres. Our results indicate that the theory of jetting during the collision of thin plates can be used to predict the conditions when jetting will occur. However, we find current analytic models do not make accurate predictions of the amount of jetted mass. Our work indicates that the amount of jetted mass is independent of model resolution as long as some jetted material is resolved. This is the result of lower velocity material dominating the mass of the jet.

  5. Penetration of projectiles into granular targets.

    PubMed

    Ruiz-Suárez, J C

    2013-06-01

    Energetic collisions of subatomic particles with fixed or moving targets have been very valuable to penetrate into the mysteries of nature. But the mysteries are quite intriguing when projectiles and targets are macroscopically immense. We know that countless debris wandering in space impacted (and still do) large asteroids, moons and planets; and that millions of craters on their surfaces are traces of such collisions. By classifying and studying the morphology of such craters, geologists and astrophysicists obtain important clues to understand the origin and evolution of the Solar System. This review surveys knowledge about crater phenomena in the planetary science context, avoiding detailed descriptions already found in excellent papers on the subject. Then, it examines the most important results reported in the literature related to impact and penetration phenomena in granular targets obtained by doing simple experiments. The main goal is to discern whether both schools, one that takes into account the right ingredients (planetary bodies and very high energies) but cannot physically reproduce the collisions, and the other that easily carries out the collisions but uses laboratory ingredients (small projectiles and low energies), can arrive at a synergistic intersection point. PMID:23660625

  6. Fundamental Aerodynamic Investigations for Development of Arrow-Stabilized Projectiles

    NASA Technical Reports Server (NTRS)

    Kurzweg, Hermann

    1947-01-01

    The numerous patent applications on arrow-stabilized projectiles indicate that the idea of projectiles without spin is not new, but has appeared in various proposals throughout the last decades. As far as projectiles for subsonic speeds are concerned, suitable shapes have been developed for sometime, for example, numerous grenades. Most of the patent applications, though, are not practicable particularly for projectiles with supersonic speed. This is because the inventor usually does not have any knowledge of aerodynamic flow around the projectile nor any particular understanding of the practical solution. The lack of wind tunnels for the development of projectiles made it necessary to use firing tests for development. These are obviously extremely tedious or expensive and lead almost always to failures. The often expressed opinion that arrow-stabilized projectiles cannot fly supersonically can be traced to this condition. That this is not the case has been shown for the first time by Roechling on long projectiles with foldable fins. Since no aerodynamic investigations were made for the development of these projectiles, only tedious series of firing tests with systematic variation of the fins could lead to satisfactory results. These particular projectiles though have a disadvantage which lies in the nature cf foldable fins. They occasionally do not open uniformly in flight, thus causing unsymmetry in flow and greater scatter. The junctions of fins and body are very bad aerodynamically and increase the drag. It must be possible to develop high-performance arrow-stabilized projectiles based on the aerodynamic research conducted during the last few years at Peenemuende and new construction ideas. Thus the final shape, ready for operational use, could be developed in the wind tunnel without loss of expensive time in firing tests. The principle of arrow-stabilized performance has been applied to a large number of caliburs which were stabilized by various means Most

  7. High-accuracy optical clock based on the octupole transition in 171Yb+.

    PubMed

    Huntemann, N; Okhapkin, M; Lipphardt, B; Weyers, S; Tamm, Chr; Peik, E

    2012-03-01

    We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition (2)S(1/2)(F=0)→(2)F(7/2)(F=3) in a single trapped (171)Yb(+) ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f(13)6s(2) configuration of the upper state. The electric-quadrupole moment of the (2)F(7/2) state is measured as -0.041(5)ea(0)(2), where e is the elementary charge and a(0) the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe-light-induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1×10(-17). The frequency is measured as 642 121 496 772 645.15(52) Hz. PMID:22463621

  8. High-Accuracy Optical Clock Based on the Octupole Transition in Yb+171

    NASA Astrophysics Data System (ADS)

    Huntemann, N.; Okhapkin, M.; Lipphardt, B.; Weyers, S.; Tamm, Chr.; Peik, E.

    2012-03-01

    We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition S1/22(F=0)→F7/22(F=3) in a single trapped Yb+171 ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f136s2 configuration of the upper state. The electric-quadrupole moment of the F7/22 state is measured as -0.041(5)ea02, where e is the elementary charge and a0 the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe-light-induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1×10-17. The frequency is measured as 642 121 496 772 645.15(52) Hz.

  9. Non-Axial Octupole Deformations and Tetrahedral Symmetry in Heavy Nuclei

    SciTech Connect

    Mazurek, Katarzyna; Dudek, Jerzy

    2005-11-21

    The total energies of about 120 nuclei in the Thorium region have been calculated within the macroscopic-microscopic method in the 5-dimensional space of deformation parameters {alpha}20, {alpha}22, {alpha}30, {alpha}32 and {alpha}40. The macroscopic energy term contains the nuclear surface-curvature dependence as proposed within the LSD approach. The microscopic energies are calculated with the Woods-Saxon single particle potential employing the universal set of parameters.We study a possible presence of the octupole axial and non-axial degrees of freedom all-over in the ({beta}, {gamma})-plane focussing on the ground-states, secondary minima and in the saddle points. In fact, a competition between axial and tri-axial octupole deformation parameters is obtained at the saddle points and in the secondary minima for many isotones with N > 136. The presence of the tetrahedral symmetry minima is predicted in numerous nuclei in the discussed region, although most of the time at relatively high excitation energies.

  10. Hyperfine-induced electric dipole contributions to the electric octupole and magnetic quadrupole atomic clock transitions

    NASA Astrophysics Data System (ADS)

    Dzuba, V. A.; Flambaum, V. V.

    2016-05-01

    Hyperfine-induced electric dipole contributions may significantly increase probabilities of otherwise very weak electric octupole and magnetic quadrupole atomic clock transitions (e.g., transitions between s and f electron orbitals). These transitions can be used for exceptionally accurate atomic clocks, quantum information processing, and the search for dark matter. They are very sensitive to new physics beyond the standard model, such as temporal variation of the fine-structure constant, the Lorentz invariance, and Einstein equivalence principle violation. We formulate conditions under which the hyperfine-induced electric dipole contribution dominates and perform calculations of the hyperfine structure and E3, M2 and the hyperfine-induced E1 transition rates for a large number of atoms and ions of experimental interest. Due to the hyperfine quenching the electric octupole clock transition in +173Yb is 2 orders of magnitude stronger than that in currently used +171Yb. Some enhancement is found in 13+143Nd, 14+149Pm, 14+147Sm, and 15+147Sm ions.

  11. Construction and Operational Experience with a Superconducting Octupole Used to Trap Antihydrogen

    SciTech Connect

    Wanderer P.; Escallier, J.; Marone, A.; Parker, B.

    2011-09-06

    A superconducting octupole magnet has seen extensive service as part of the ALPHA experiment at CERN. ALPHA has trapped antihydrogen, a crucial step towards performing precision measurements of anti-atoms. The octupole was made at the Direct Wind facility by the Superconducting Magnet Division at Brookhaven National Laboratory. The magnet was wound with a six-around-one NbTi cable about 1 mm in diameter. It is about 300 mm long, with a radius of 25 mm and a peak field at the conductor of 4.04 T. Specific features of the magnet, including a minimal amount of material in the coil and coil ends with low multipole content, were advantageous to its use in ALPHA. The magnet was operated for six months a year for five years. During this time it underwent about 900 thermal cycles (between 4K and 100K). A novel operational feature is that during the course of data-taking the magnet was repeatedly shut off from its 950 A operating current. The magnet quenches during the shutoff, with a decay constant of 9 ms. Over the course of the five years, the magnet was deliberately quenched many thousands of times. It still performs well.

  12. Corrected Launch Speed for a Projectile Motion Laboratory

    ERIC Educational Resources Information Center

    Sanders, Justin M.; Boleman, Michael W.

    2013-01-01

    At our university, students in introductory physics classes perform a laboratory exercise to measure the range of a projectile fired at an assigned angle. A set of photogates is used to determine the initial velocity of the projectile (the launch velocity). We noticed a systematic deviation between the experimentally measured range and the range…

  13. Microcraters formed in glass by projectiles of various densities

    NASA Technical Reports Server (NTRS)

    Vedder, J. F.; Mandeville, J.-C.

    1974-01-01

    An experiment was conducted investigating the effect of projectile density on the structure and size of craters in soda lime glass and fused quartz. The projectiles were spheres of polystyrene-divinylbenzene (PS-DVB), aluminum, and iron with velocities between 0.5 and 15 km/sec and diameters between 0.4 and 5 microns. The projectile densities spanned the range expected for primary and secondary particles of micrometer size at the lunar surface, and the velocities spanned the lower range of micrometeoroid velocities and the upper range of secondary projectile velocities. There are changes in crater morphology as the impact velocity increases, and the transitions occur at lower velocities for the projectiles of higher density. The sequence of morphological features of the craters found for PS-DVB impacting soda lime glass for increasing impact velocity, described in a previous work (Mandeville and Vedder, 1971), also occurs in fused quartz and in both targets with the more dense aluminum and iron projectiles. Each transition in morphology occurs at impact velocities generating a certain pressure in the target. High density projectiles require a lower velocity than low-density projectiles to generate a given shock pressure.

  14. One-phonon octupole vibrational states in 211At, 212Rn, 213Fr and 214Ra with N = 126

    NASA Astrophysics Data System (ADS)

    Hwang, J. K.; Hamilton, J. H.; Ramayya, A. V.

    2013-12-01

    Excited high spin states in 211At, 212Rn, 213Fr and 214Ra with N = 126 are reorganized and interpreted in terms of the stretched weak coupling of an octupole 3- phonon. Nearly identical sequences of levels with ΔI = 3 and the parity change are found, for the first time, up to 25- for 20 states of 214Ra, up to 35- for 36 states of 212Rn and up to 53/2+ for 16 states of 213Fr. The stretched weak coupling of an octupole phonon is extended up to the highest excitation energy of 11355 keV for 212Rn which has the largest experimental B( E3) value of 44.1(88) W.u. for the 11- → 8{2/+} transition. The stretched weak coupling of an octupole 3- phonon needs to be considered when single particle configurations are assigned to high spin states. Average octupole excitation energies of 657(51) keV for 211At, 1101(28) keV for 212Rn, 667(25) keV for 213Fr, and 709(25) keV for 214Ra are obtained. The calculated level enegies are in a good agreement with the experimental level energies within the error limit of 4.3%.

  15. Projectile impact Hugoniot parameters for selected materials

    SciTech Connect

    Vigil, M G

    1989-08-01

    The Rankine Hugoniot equation relating the conversion of momentum across a shock front and the empirical relationship for shock velocity as a function of particle velocity are used to calculate the impact pressures for selected materials. The shock velocity and particle velocities are then calculated as a function of impact pressures. The calculated data are graphically presented sets of three figures for the selected materials as follows: Impact pressure as a function of impact velocity, impact pressure as a function of particle velocity, impact pressure as a function of shock velocity. Given the projectile impact velocity and material Hugoniot information, this graphical representation of the data allows for a fast approximation of the impact pressure particle velocity, and shock velocity in the target material. 9 refs., 1 fig., 3 tabs.

  16. Turbulent Flow Past Projectiles: A Computational Investigation

    NASA Astrophysics Data System (ADS)

    Mehmedagic, Igbal; Carlucci, Donald; Buckley, Liam; Carlucci, Pasquale; Thangam, Siva

    2010-11-01

    Projectiles with free spinning bases are often used for smart munitions to provide effective control, stability and terminal guidance. Computational investigations are performed for flow past cylinders aligned along their axis where a base freely spins while attached to and separated at various distances from a non-spinning fore-body. The energy spectrum is modified to incorporate the effects of swirl and rotation using a parametric characterization of the model coefficients. An efficient finite-volume algorithm is used to solve the time-averaged equations of motion and energy along with the modeled form of transport equations for the turbulence kinetic energy and the scalar form of turbulence dissipation. Computations are performed for both rigid cylinders as well as cylinders with free-spinning bases. Experimental data for a range of spin rates and free stream flow conditions obtained from subsonic wind tunnel with sting-mounted spinning cylinders is used for validating the computational findings.

  17. Experimental and numerical study on fragmentation of steel projectiles

    NASA Astrophysics Data System (ADS)

    Råkvaag, K. G.; Børvik, T.; Hopperstad, O. S.; Westermann, I.

    2012-08-01

    A previous experimental study on penetration and perforation of circular Weldox 460E target plates with varying thicknesses struck by blunt-nose projectiles revealed that fragmentation of the projectile occurred if the target thickness or impact velocity exceeded a certain value. Thus, numerical simulations that do not account for fragmentation during impact can underestimate the perforation resistance of protective structures. Previous numerical studies have focused primarily on the target plate behaviour. This study considers the behaviour of the projectile and its possible fragmentation during impact. Hardened steel projectiles were launched at varying velocities in a series of Taylor tests. The impact events were captured using a high-speed camera. Fractography of the fragmented projectiles showed that there are several fracture mechanisms present during the fragmentation process. Tensile tests of the projectile material revealed that the hardened material has considerable variations in yield stress and fracture stress and strain. In the finite element model, the stress-strain behaviour from tensile tests was used to model the projectile material with solid elements and the modified Johnson-Cook constitutive relation. Numerical simulations incorporating the variations in material properties are capable of reproducing the experimental fracture patterns, albeit the predicted fragmentation velocities are too low.

  18. Veterinary Forensics: Firearms and Investigation of Projectile Injury.

    PubMed

    Bradley-Siemens, N; Brower, A I

    2016-09-01

    Projectile injury represents an estimated 14% of reported animal cruelty cases in the United States. Cases involving projectiles are complicated by gross similarities to other common types of injury, including bite wounds and motor vehicle injuries, by weapons and ammunition not commonly recognized or understood by veterinary medical professionals, and by required expertise beyond that employed in routine postmortem examination. This review describes the common types of projectile injuries encountered within the United States, as well as firearms and ammunition associated with this form of injury. The 3 stages of ballistics-internal, external, and terminal-and wounding capacity are discussed. A general understanding of firearms, ammunition, and ballistics is necessary before pursuing forensic projectile cases. The forensic necropsy is described, including gunshot wound examination, projectile trajectories, different imaging procedures, collection and storage of projectile evidence, and potential advanced techniques for gunpowder analysis. This review presents aspects of projectile injury investigation that must be considered in tandem with standard postmortem practices and procedures to ensure reliable conclusions are reached for medicolegal as well as diagnostic purposes. PMID:27312366

  19. Delivering a projectile component to the vestan regolith

    NASA Astrophysics Data System (ADS)

    Daly, R. Terik; Schultz, Peter H.

    2016-01-01

    Dark material on Vesta may consist of carbonaceous chondrite-like material delivered by impact events. This study uses hypervelocity impact experiments to assess the viability of the impact delivery hypothesis. Experiments reveal that impact events deliver significant fractions of the projectile to the target during impacts at average vestan speeds. Hence, dark material can plausibly be delivered to Vesta by impacts, with the projectile component accumulating in the regolith with time. Projectile retention is sensitive to impact angle, ranging from 7% for 30° impacts (measured from horizontal) to 72% for vertical impacts. Averaged over the probability distribution of impact angles, 17% of the projectile's mass remains in or near the crater. Projectile-contaminated breccias largely remain inside the crater for vertical impacts. In oblique impacts, projectile-contaminated pieces concentrate downrange beyond the crater rim. Based on experiments, projectile delivery is expected for typical vestan impact conditions, not only for extraordinary events such as low-probability and very low-speed (e.g., <2 km s-1) impacts. These experiments indicate that other (non-dark) impactors contaminate the vestan regolith. Regolith-laden bodies in environments with similar impact speeds also may accrete significant amounts of foreign debris.

  20. Octupole Magnet For Soft X Ray Magnetic Dichroism Experiments: Design and Performance

    SciTech Connect

    Arenholz, Elke; Prestemon, Soren O.

    2004-05-12

    An octupole magnet endstation for soft x ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x ray incidence while keeping the relative orientation of magnetic field and sample fixed.

  1. Structure and dynamics of ion clusters in linear octupole traps: Phase diagrams, chirality, and melting mechanisms

    SciTech Connect

    Yurtsever, E.; Onal, E. D.; Calvo, F.

    2011-05-15

    The stable structures and melting dynamics of clusters of identical ions bound by linear octupole radiofrequency traps are theoretically investigated by global optimization methods and molecular dynamics simulations. By varying the cluster sizes in the range of 10-1000 ions and the extent of trap anisotropy by more than one order of magnitude, we find a broad variety of stable structures based on multiple rings at small sizes evolving into tubular geometries at large sizes. The binding energy of these clusters is well represented by two contributions arising from isotropic linear and octupolar traps. The structures generally exhibit strong size effects, and chiral arrangements spontaneously emerge in many crystals. Sufficiently large clusters form nested, coaxial tubes with different thermal stabilities. As in isotropic octupolar clusters, the inner tubes melt at temperatures that are lower than the overall melting point.

  2. High-spin octupole yrast levels in {sup 216}Rn{sub 86}

    SciTech Connect

    Debray, M.E.; Davidson, J.; Davidson, M.; Kreiner, A. J.; Cardona, M. A.; Hojman, D.; Napoli, D.R.; De Angelis, G.; De Poli, M.; Gadea, A.; Lenzi, S.; Bazzacco, D.; Lunardi, S.; Rossi-Alvarez, C.; Ur, C.A.; Medina, N.

    2006-02-15

    The yrast level structure of {sup 216}Rn has been studied using in-beam spectroscopy {alpha}-{gamma}-{gamma} coincidence techniques through the {sup 208}Pb({sup 18}O, 2{alpha}2n) reaction in the 91-93 MeV energy range, using the 8{pi} GASP-ISIS spectrometer at Legnaro. The level scheme of {sup 216}Rn resulting from this study shows alternating parity bands only above a certain excitation energy. From this result, the lightest nucleus showing evidence of octupole collectivity at low spins is still {sup 216}Fr, thereby defining the lowest-mass corner for this kind of phenomenon as N{>=}129 and Z{>=}87.

  3. Octupole magnet for soft X ray magnetic dichroism experiments: Design and performance

    SciTech Connect

    Arenholz, Elke; Prestemon, Soren O.

    2003-08-24

    An octupole magnet endstation for soft x-ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x-ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x-ray incidence while keeping the relative orientation of magnetic field and sample fixed.

  4. Test of the transport properties of a helical electrostatic quadrupole and quasi-octupole

    SciTech Connect

    Xiu, L.; Ohnuma, Shoroku; Wang, K. . Dept. of Physics); Meitzler, C.R.; Xu, Y. . Dept. of Physics)

    1993-01-01

    A third-generation continuous helical electrostatic quadrupole (HESQ) lens has been built and tested. The new HESQ is 21.5 cm long and has a 3.6 cm diameter aperture. The HESQ has been tested under two separate conditions: with a pulsed 25 keV, 0.5 mA proton beam; and a 25 keV, 10 mA proton beam. The input emittance was fixed using a multi-aperture collimator. A comparison is made between experiment and numerical simulations for a wide variety of operating conditions. A second possible operating mode is the quasi-octupole mode, which offers significantly reduced aberration when compared to the quadrupole mode. The results of preliminary tests in this operating mode will be presented.

  5. Test of the transport properties of a helical electrostatic quadrupole and quasi-octupole

    SciTech Connect

    Xiu, L.; Ohnuma, Shoroku; Wang, K.; Meitzler, C.R.; Xu, Y.

    1993-06-01

    A third-generation continuous helical electrostatic quadrupole (HESQ) lens has been built and tested. The new HESQ is 21.5 cm long and has a 3.6 cm diameter aperture. The HESQ has been tested under two separate conditions: with a pulsed 25 keV, 0.5 mA proton beam; and a 25 keV, 10 mA proton beam. The input emittance was fixed using a multi-aperture collimator. A comparison is made between experiment and numerical simulations for a wide variety of operating conditions. A second possible operating mode is the quasi-octupole mode, which offers significantly reduced aberration when compared to the quadrupole mode. The results of preliminary tests in this operating mode will be presented.

  6. Rotation induced octupole correlations in the neutron-deficient 109Te nucleus

    NASA Astrophysics Data System (ADS)

    de Angelis, G.; Fahlander, C.; Gadea, A.; Farnea, E.; Bazzacco, D.; Belcari, N.; Blasi, N.; Bizzeti, P. G.; Bizzeti-Sona, A.; de Acuña, D.; de Poli, M.; Grawe, H.; Johnson, A.; Lo Bianco, G.; Lunardi, S.; Napoli, D. R.; Nyberg, J.; Pavan, P.; Persson, J.; Rossi Alvarez, C.; Rudolph, D.; Schubart, R.; Spolaore, P.; Wyss, R.; Xu, F.

    1998-10-01

    High spin states in the neutron deficient nucleus 109Te have been populated with the 58Ni+54Fe reaction at 220 MeV and investigated through γ-spectroscopy methods at the GASP spectrometer making use of reaction channel selection with the ISIS Si-ball. The level scheme has been extended up to an excitation energy of ~12.1 MeV. The spins and parities of the observed levels are assigned tentatively supporting the identification of two bands of opposite parity connected by strong dipole transitions inferred to be of E1 character. Octupole correlations in 109Te induced by rotation are suggested as the cause of this effect.

  7. First Atomic Electric Dipole Moment Limit Derived from an Octupole-Deformed Nucleus

    NASA Astrophysics Data System (ADS)

    Parker, Richard; Bishof, Michael; Kalita, Mukut; Lemke, Nathan; Dietrich, Matt; Bailey, Kevin; Greene, John; Holt, Roy; Korsch, Wolfgang; Lu, Zheng-Tian; Mueller, Peter; O'Connor, T. P.; Singh, Jaideep

    2015-05-01

    Ra-225 (half-life = 15 d, nuclear spin = 1/2) is a promising isotope for a measurement of the EDM of a diamagnetic atom. Due to its large nuclear octupole deformation and high atomic mass, the EDM sensitivity of Ra-225 is expected to be 2-3 orders of magnitude larger than that of Hg-199. We demonstrate an efficient multiple-stage apparatus in which radium atoms are first loaded into a MOT, then transferred into a movable optical-dipole trap (ODT) that carries the atoms over 1 m to a magnetically-shielded science chamber, loaded into a standing-wave ODT, polarized, and then allowed to precess in magnetic and electric fields. We will discuss our first measurement of the EDM of Ra-225, as well as plans for future improvements. This work is supported by DOE, Office of Nuclear Physics (DE-AC02-06CH11357).

  8. Interplay between octupole and quasiparticle excitations in {sup 178}Hg and {sup 180}Hg

    SciTech Connect

    Kondev, F. G.; Janssens, R. V. F.; Carpenter, M. P.; Abu Saleem, K.; Ahmad, I.; Alcorta, M.; Amro, H.; Bhattacharyya, P.; Brown, L. T.; Caggiano, J.

    2000-10-01

    Excited structures in the Z=80, {sup 178}Hg (N=98), and {sup 180}Hg (N=100) isotopes have been investigated with the Gammasphere spectrometer in conjunction with the recoil-decay tagging technique. The present data extend the previously known ground-state bands to higher spin and excitation energy. Negative parity bands with a complex decay towards the low spin states arising from both the prolate-deformed and the nearly spherical coexisting minima have been observed for the first time in both nuclei. It is shown that these sequences have characteristics in common with negative-parity bands in the heavier even-even Hg isotopes as well as in the Os and Pt isotones. These structures are interpreted as being associated at low spin with an octupole vibration which is crossed at moderate frequency by a shape driving, two-quasiproton excitation.

  9. Role of Projectile Degrees of Freedom in Sub-Barrier Fusion Dynamics

    NASA Astrophysics Data System (ADS)

    Gautam, Manjeet Singh

    2016-04-01

    This work theoretically investigates the role of the projectile degrees of freedom on the fusion dynamics of various heavy-ion fusion reactions. The impact of the projectile breakup channel is studied for the fusion mechanism of the 4 9 Be + 39 89 Y, 6 12 C + 39 89 Y, and 16 32,34 S + 39 89 Y reactions within the view of the coupled channel approach and the energy-dependent Woods-Saxon potential model (EDWSP model). The above-barrier fusion cross-section data of the 4 9 Be + 39 89 Y reaction is suppressed by about 20 % with respect to the theoretical predictions of the coupled channel approach and the single barrier penetration model while this suppression factor is reduced to 10 % within the context of the EDWSP model calculations. Such fusion hindrance at above-barrier energies can be understood in terms of the projectile breakup effects that arise due to its low breakup threshold. However, the observed fusion enhancement of the 6 12 C + 39 89 Y and 16 32,34 S + 39 89 Y reactions, wherein the colliding pairs are stable against breakup, is adequately explained by the EDWSP model and the coupled channel approach in the whole range of energy around the Coulomb barrier. This reveals that the energy dependence in the nucleus-nucleus potential governs barrier modification effects (barrier height, barrier position, barrier curvature) in closely similar way as reflected from the coupled channel formulation.

  10. Penetration of Granular Projectiles into a Water Target

    PubMed Central

    González-Gutiérrez, Jorge; Carrillo-Estrada, J. L.; Ruiz-Suárez, J. C.

    2014-01-01

    The penetration of low-speed projectiles into a water target has been studied in the last several years to understand the physics behind the formation and collapse of cavities. In such studies, the projectiles employed were solid bodies or liquid drops. Here we report similar impact experiments using granular projectiles, with the aim to investigate how the morphology of the cavities is determined by the balance between the dynamic pressure exerted by the fluid and the cohesive strength of the impactors. From the results we present and discuss in this manuscript, we speculate on the dynamics of meteorite disintegration in the atmosphere of our planet. PMID:25342448

  11. Penetration of granular projectiles into a water target.

    PubMed

    González-Gutiérrez, Jorge; Carrillo-Estrada, J L; Ruiz-Suárez, J C

    2014-01-01

    The penetration of low-speed projectiles into a water target has been studied in the last several years to understand the physics behind the formation and collapse of cavities. In such studies, the projectiles employed were solid bodies or liquid drops. Here we report similar impact experiments using granular projectiles, with the aim to investigate how the morphology of the cavities is determined by the balance between the dynamic pressure exerted by the fluid and the cohesive strength of the impactors. From the results we present and discuss in this manuscript, we speculate on the dynamics of meteorite disintegration in the atmosphere of our planet. PMID:25342448

  12. Corrected Launch Speed for a Projectile Motion Laboratory

    NASA Astrophysics Data System (ADS)

    Sanders, Justin M.; Boleman, Michael W.

    2013-09-01

    At our university, students in introductory physics classes perform a laboratory exercise to measure the range of a projectile fired at an assigned angle. A set of photogates is used to determine the initial velocity of the projectile (the launch velocity). We noticed a systematic deviation between the experimentally measured range and the range calculated using the speed as determined by the photogates. In this paper, we will discuss the origin of this systematic error and derive a simple formula to correct it. In particular, we find that the launch speed given by our instrument is significantly different from the actual launch speed of our projectile.

  13. Microcraters formed in glass by low density projectiles

    NASA Technical Reports Server (NTRS)

    Mandeville, J.-C.; Vedder, J. F.

    1971-01-01

    Microcraters were produced in soda-lime glass by the impact of low density projectiles of polystyrene (p = 1.06 g/cu cm) with masses between 0.7 and 62 picograms and velocities between 2 and 14 km/s. The morphology of the craters depended on the velocity and the angle of incidence of the projectiles and these are discussed in detail. It was found that the transitions in morphology of the craters formed by polystyrene spheres occurred at higher velocities than they did for more dense projectiles.

  14. Dynamic impact analysis of the M1 105mm projectile

    SciTech Connect

    Walls, J.C.; Webb, D.S.

    1993-06-01

    Evaluation of the effects of {open_quotes}rough-handling{close_quotes}-induced stresses in the nose region of a 105mm artillery projectile was performed to determine if these stresses could have contributed to the premature explosion of a projectile during a Desert Shield training mission of the 101st Army Airborne in Saudi Arabia. The rough-handling evaluations were simulated by dynamic impact analysis. It was concluded that the combined residual stress and dynamic impact-induced stress would not be of sufficient magnitude to cause cracking of the projectile in the nose region.

  15. Dynamic impact analysis of the M1 105mm projectile

    SciTech Connect

    Walls, J.C.; Webb, D.S.

    1993-06-01

    Evaluation of the effects of [open quotes]rough-handling[close quotes]-induced stresses in the nose region of a 105mm artillery projectile was performed to determine if these stresses could have contributed to the premature explosion of a projectile during a Desert Shield training mission of the 101st Army Airborne in Saudi Arabia. The rough-handling evaluations were simulated by dynamic impact analysis. It was concluded that the combined residual stress and dynamic impact-induced stress would not be of sufficient magnitude to cause cracking of the projectile in the nose region.

  16. Comparison of less lethal 40 mm sponge projectile and the 37 mm projectile for injury assessment on human thorax

    NASA Astrophysics Data System (ADS)

    Nsiampa, N.; Robbe, C.; Oukara, A.; Papy, A.

    2012-08-01

    Since there is an increasing interest in avoiding human body injury in diverse situations like crowd control or peacekeeping missions, less lethal ammunition are more and more used. In this study we focus only on kinetic energy non-lethal (KENLW) projectiles. Their desired effects on human body are the temporary incapacitation through blunt trauma. There are different types of KENLW projectiles ranging from rigid to deformable projectiles. Unfortunately, the effects of such projectiles are not really well known as it is difficult to measure the force transmitted to the human body or the related deformation. Because the potential of injury excludes human living tests, tests are performed on cadavers, animals or human tissue surrogates. Besides these tests, numerical simulations are more and more used to gain more understanding, to assess or to predict the effects of this kind of projectile on human body. In this paper a comparison based on the viscous criterion between the 37 mm rigid projectile and the 40 mm sponge projectile was made.

  17. Perforation of woven fabric by spherical projectiles

    SciTech Connect

    Shim, V.P.W.; Tan, V.B.C.; Tay, T.E.

    1995-12-31

    Rectangular specimens of Twaron{reg_sign} fabric, clamped on two opposite sides, are subjected to impact perforation by 9.5 mm diameter spherical steel projectiles at speeds ranging from 140 m/s to 420 m/s. This plain woven fabric, comprising PPTA (poly-paraphenylene terepthalamide) fibers, is commonly employed in flexible an-nor applications. Its perforation response is examined in terms of residual velocity, energy absorbed and resulting deformation patterns. The existence of a critical or transition impact velocity, beyond which there is a significant reduction in energy absorbed by perforation, is observed. Differences in creasing and deformation induced in specimens are also demarcated by this transition impact velocity. Effects of difference in boundary conditions (clamped and free) on yarn breakage are also noted. A numerical model, based on an initially orthogonal network of pin-jointed bars interconnected at nodes, is formulated to simulate the fabric. Fiber yam mechanical properties are represented via a three-element spring-dashpot model which encapsulates viscoelastic behavior and fiber failure. Numerical results exhibit good correlation with experimental observations in terms of prediction of threshold perforation velocity, energy absorbed, occurrence of a transition critical velocity and fabric deformation characteristics.

  18. 32. VAL, DETAIL SHOWING LOADING PLATFORM, PROJECTILE LOADING CAR, LAUNCHER ...

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

    32. VAL, DETAIL SHOWING LOADING PLATFORM, PROJECTILE LOADING CAR, LAUNCHER SLAB AND UNDERSIDE OF LAUNCHER BRIDGE LOOKING SOUTHWEST. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  19. 22. Emplacement no. 1 showing well for projectile hoist at ...

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

    22. Emplacement no. 1 showing well for projectile hoist at right. at left is passage toward the shot gallery. View looking northwest - Fort Wadsworth Battery Romeyn B. Ayers, South side of Ayers Road, Staten Island, Rosebank, Richmond County, NY

  20. Penetration analysis of projectile with inclined concrete target

    NASA Astrophysics Data System (ADS)

    Kim, S. B.; Kim, H. W.; Yoo, Y. H.

    2015-09-01

    This paper presents numerical analysis result of projectile penetration with concrete target. We applied dynamic material properties of 4340 steels, aluminium and explosive for projectile body. Dynamic material properties were measured with static tensile testing machine and Hopkinson pressure bar tests. Moreover, we used three concrete damage models included in LS-DYNA 3D, such as SOIL_CONCRETE, CSCM (cap model with smooth interaction) and CONCRETE_DAMAGE (K&C concrete) models. Strain rate effect for concrete material is important to predict the fracture deformation and shape of concrete, and penetration depth for projectiles. CONCRETE_DAMAGE model with strain rate effect also applied to penetration analysis. Analysis result with CSCM model shows good agreement with penetration experimental data. The projectile trace and fracture shapes of concrete target were compared with experimental data.

  1. Oblique Perforation of Thick Metallic Plates by Rigid Projectiles

    NASA Astrophysics Data System (ADS)

    Chen, Xiaowei; Li, Qingming; Fan, Saucheong

    2006-08-01

    Oblique perforation of thick metallic plates by rigid projectiles with various nose shapes is studied in this paper. Two perforation mechanisms, i.e., the hole enlargement for a sharp projectile nose and the plugging formation for a blunt projectile nose, are considered in the proposed analytical model. It is shown that the perforation of a thick plate is dominated by several non-dimensional numbers, i.e., the impact function, the geometry function of projectile, the non-dimensional thickness of target and the impact obliquity. Explicit formulae are obtained to predict the ballistic limit, residual velocity and directional change for the oblique perforation of thick metallic plates. The proposed model is able to predict the critical condition for the occurrence of ricochet. The proposed model is validated by comparing the predictions with other existing models and independent experimental data.

  2. Fusion and direct reactions for strongly and weakly bound projectiles

    NASA Astrophysics Data System (ADS)

    Hugi, M.; Lang, J.; Müller, R.; Ungricht, E.; Bodek, K.; Jarczyk, L.; Kamys, B.; Magiera, A.; Strzałkowski, A.; Willim, G.

    1981-09-01

    The interaction of 6Li, 9Be and 12C projectiles with a 28Si target was investigated by measuring the angular distributions of the elastically scattered projectiles and of the emitted protons, deuterons and α-particles. The experiment was performed in order to deduce direct and compound nucleus process contributions to the total reaction cross section and to study the influence of the projectile structure on the relative importance of these two mechanisms. Optical model parameters and therefore the total reaction cross section are strongly influenced by the binding energy of the projectile. The parameters of the Glas-Mosel model describing the fusion reaction vary smoothly with the atomic number. In the system 9Be + 28Si around 50% of all reactions are direct processes even at energies near the Coulomb barrier, whereas in the other systems the direct part amounts to 15 % ( 12C) and 30 % ( 6Li) only.

  3. Projectile-power-compressed magnetic-field pulse generator

    SciTech Connect

    Barlett, R.H.; Takemori, H.T.; Chase, J.B.

    1983-03-17

    Design considerations and experimental results are presented of a compressed magnetic field pulsed energy source. A 100-mm-diameter, gun-fired projectile of approx. 2MJ kinetic energy was the input energy source. An initial magnetic field was trapped and compressed by the projectile. With a shorted load, a magajoule in a nanohenry was the design goal, i.e., 50 percent energy transformation from kinetic to magnetic. Five percent conversion was the highest recorded before gauge failure.

  4. Response of simulated propellants and explosives to projectile impact

    SciTech Connect

    Yuan, W.

    1990-11-01

    This dissertation deals with experimental, analytical and numerical investigations into the response of two types of simulated propellants and explosives, known as Propergol, to projectile impact. The targets consisted of a polymeric mixture composed of potassium chloride, plaster of Paris and a polyurethane binder. Following the determination of the constitutive behavior of Propergol, experiments were conducted to study their penetration, perforation and fragmentation by projectiles. Both pneumatic and powder guns were employed in the tests, perfragmentation by projectiles. Both pneumatic and powder guns were employed in the tests, permitting impact velocities ranging from 40 to 1100 m/s, for flat- and conically-tipped as well as armor-piercing projectiles. The specimens include monolithic, composite and constrained Propergol circular disks and cylinders of 140 mm diameter with thicknesses ranging from 9 to 90 mm. Penetration tests were also conducted on model warheads loaded with the simulant material. Ballistic limit velocities for various target/projectile combinations were determined. Damage modes, such as cracking and fragmentation, were examined using experimental evidence including high-speed film data and microscopic photographs. Two types of fragments, Propergol clusters and crystalline particles, were recognized, and their size distributions were found to fit exponential functions. The dependent of fragment number and volume on initial projectile velocity was also studied. 103 refs., 172 figs., 19 tabs.

  5. Orientation estimation algorithm applied to high-spin projectiles

    NASA Astrophysics Data System (ADS)

    Long, D. F.; Lin, J.; Zhang, X. M.; Li, J.

    2014-06-01

    High-spin projectiles are low cost military weapons. Accurate orientation information is critical to the performance of the high-spin projectiles control system. However, orientation estimators have not been well translated from flight vehicles since they are too expensive, lack launch robustness, do not fit within the allotted space, or are too application specific. This paper presents an orientation estimation algorithm specific for these projectiles. The orientation estimator uses an integrated filter to combine feedback from a three-axis magnetometer, two single-axis gyros and a GPS receiver. As a new feature of this algorithm, the magnetometer feedback estimates roll angular rate of projectile. The algorithm also incorporates online sensor error parameter estimation performed simultaneously with the projectile attitude estimation. The second part of the paper deals with the verification of the proposed orientation algorithm through numerical simulation and experimental tests. Simulations and experiments demonstrate that the orientation estimator can effectively estimate the attitude of high-spin projectiles. Moreover, online sensor calibration significantly enhances the estimation performance of the algorithm.

  6. a Study of Ricochet Phenomenon for Inclined Impact of Projectile

    NASA Astrophysics Data System (ADS)

    Jo, Jong-Hyun; Lee, Young-Shin

    In this study, the numerical simulation using AUTODYN-3D program was investigated for trajectory prediction for inclined impacts of projectiles. The penetration and perforation of polycarbonate(PC) plate by 7.62 mm projectile was investigated numerically. The characteristic structure of the projectile's trajectory in the PC plates was studied. Two combined failure criteria were used in the target plate, and the target plate was modeled with the properties of polycarbonate for simulating the ricochet phenomenon. The numerical analyses were used to study the effect of the angle of inclination on the trajectory and kinetic energy of the projectile. The dynamic deformation behaviors tests of PC were compared with numerical simulation results which can be used for predictive purpose. Ricochet phenomenon for angles of inclination of 0° ≤ θ ≤ 20° in the analysis. The projectile perforated the plate for θ > 30°, thus defined a failure envelope for numerical configuration. The numerical analyses was used to study the effect under the projectile impact velocity on the depth of penetration(DOP).

  7. Coupling of nuclear quadrupole and octupole degrees of freedom in an angular momentum dependent potential of two deformation variables

    SciTech Connect

    Minkov, N.; Yotov, P.; Drenska, S.; Scheid, W.; Bonatsos, Dennis; Lenis, D.; Petrellis, D.

    2006-04-26

    We propose a collective rotation-vibration Hamiltonian of nuclei in which the axial quadrupole {beta}2 and octupole {beta}3 variables are coupled through the centrifugal interaction. We consider that the system oscillates between positive and negative {beta}3-values by rounding a potential core in the ({beta}2,{beta}3)- space. We examine the effect of the 'rounding' in the structure of the spectrum.

  8. Tritium projectiles for fueling magnetic fusion plasmas

    SciTech Connect

    Fisher, P.W.; Gouge, M.J.

    1995-12-31

    As part of the International Thermonuclear Engineering Reactor (ITER) plasma fueling development program, Oak Ridge National Laboratory (ORNL) has fabricated a pellet (cylindrical projectile of frozen hydrogenic gas at a temperature in the range 6--16 K) injection system to test the mechanical and thermal properties of extruded tritium, a radioactive isotope of hydrogen. This repeating, single-stage, pneumatic injector, called the Tritium-Proof-of-Principle Phase 2 (TPOP-2) Pellet Injector, has a piston-driven mechanical extruder and is designed to extrude and accelerate hydrogenic pellets sized for the ITER device. The TPOP-2 program has the following development goals: evaluate the feasibility of extruding tritium and deuterium-tritium (D-T) mixtures for use in future pellet injection systems; determine the mechanical and thermal properties of tritium and D-T extrusions; integrate, test, and evaluate the extruder in a repeating, single-stage light gas gun that is sized for the ITER application (pellet diameter {approximately} 7 to 8 mm); evaluate options for recycling propellant and extruder exhaust gas; evaluate operability and reliability of ITER prototypical fueling systems in an environment of significant tritium inventory that requires secondary and room containment systems. In initial tests with deuterium feed at ORNL, up to 13 pellets have been extruded at rates up to 1 Hz and accelerated to speeds of 1.0 to 1.1 km/s, using hydrogen propellant gas at a supply pressure of 65 bar. The pellets, typically 7.4 mm in diameter and up to 11 mm in length, are the largest cryogenic pellets produced by the fusion program to date. These pellets represent about a 11% density perturbation to ITER. Hydrogenic pellets will be used in ITER to sustain the fusion power in the plasma core and may be crucial in reducing first-wall tritium inventories by a process called isotopic fueling in which tritium-rich pellets fuel the burning plasma core and deuterium gas fuels the edge.

  9. Search for stable octupole deformation in the nucleus /sup 225/Fr

    SciTech Connect

    Burke, D.G.; Kurcewicz, W.; Loevhoeiden, G.; Nyboe, K.; Thorsteinsen, T.F.; Gietz, H.; Kaffrell, N.; Rogowski, J.; Naumann, R.A.; Borge, M.J.G.; and others

    1987-12-10

    The level structure of /sup 225/Fr has been studied from the /sup 225/Rn(..beta../sup -/) decay in on-line experiments at the ISOLDE facility. A level scheme was constructed on the basis of gamma--gamma coincidence data, and the multipolarities of many transitions were established by conversion electron measurements. Levels in /sup 225/Fr were also studied with the /sup 226/Ra(t,..cap alpha..)/sup 225/Fr reaction at the McMaster University Accelerator Laboratory, using a target of /sup 226/Ra(T/sub 1/2/ = 1600y) and a magnetic spectrograph to analyze the alpha spectra. The first three excited states, at 28.5, 82.5 and 128.2 keV, are interpreted as rotational band members based on the ground state, which is known to have I = 3/2. The (t,..cap alpha..) strengths to these levels indicate a 3/2/sup -/(532) assignment to the ground state. No evidence for an octupole deformation in /sup 225/Fr has been found so far, although analysis of data for other excited states is continuing.

  10. Search for the two-phonon octupole vibrational state in {sup 208}Pb

    SciTech Connect

    Blumenthal, D.J.; Henning, W.; Janssens, R.V.F.

    1995-08-01

    We performed an experiment to search for the two-phonon octupole vibrational state in {sup 208}Pb. Thick targets of {sup 208}Pb, {sup 209}Bi, {sup 58,64}Ni, and {sup 160}Gd were bombarded with 1305 MeV beams of were bombard {sup 208}Pb supplied by ATLAS. Gamma rays were detected using the Argonne-Notre Dame BGO gamma-ray facility, consisting of 12 Compton-suppressed germanium detectors surrounding an array of 50 BGO scintillators. We identified some 30 known gamma rays from {sup 208}Pb in the spectra gated by the 5{sup -} {yields} 3{sup -} and 3{sup -} {yields} 0{sup +} transitions in {sup 208}Pb. In addition, after unfolding these spectra for Compton response, we observed broad coincident structures in the energy region expected for the 2-phonon states. Furthermore, we confirmed the placement of a 2485 keV line observed previously in {sup 207}Pb and find no evidence consistent with the placement of this line in {sup 208}Pb. We are currently in the process of investigating the origin of the broadened lines observed in the spectra, extracting the excitation probability of states in {sup 208}Pb, and determining the relative probability of mutual excitation and neutron transfer in this reaction. An additional experiment is also being performed to collect much higher statistics germanium-germanium coincidence data for the thick {sup 208}Pb target.

  11. Evidence for octupole vibration in the superdeformed well of {sup 190}Hg from eurogam

    SciTech Connect

    Crowell, B.; Carpenter, M.P.; Janssens, R.V.F.

    1995-08-01

    Gammasphere experiments in 1993-94 brought to light the existence of an excited superdeformed (SD) band in {sup 190}Hg with the unusual property of decaying entirely to the lowest (yrast) SD band over 3-4 transitions, rather than to the normally deformed states as is usually the case in the A {approximately} 150 and A {approximately} 190 regions of superdeformation. Although M1 transitions between signature-partner SD bands were previously observed in {sup 193}Hg, no such mechanism was available to explain the situation in the even-even nucleus {sup 190}Hg, whose yrast SD band has no signature partner. The best explanation appears to lie in long-standing theoretical predictions that the SD minimum in the potential energy surface would be quite soft with respect to octupole vibrations. This would lead to enhanced E1 transitions connecting the one-phonon and zero-phonon states. The data and this interpretation were published. A shortcoming of the Gammasphere experiments was that they did not allow the definitive measurement of the energies of the gamma-ray transitions connecting the two bands, due to the very weak population of the excited band ({approximately}0.05% of the {sup 190}Hg channel) and also partly, we believed, to the angular distributions of the transitions, which were peaked near 90 degrees, where Gammasphere had few detectors.

  12. Measuring the Nuclear Magnetic Octupole Moment of a Single Trapped Barium-137 Ion

    NASA Astrophysics Data System (ADS)

    Kleczewski, Adam; Fortson, Norval; Blinov, Boris

    2009-05-01

    Recent measurements of hyperfine structure in the cesium-133 atom resolved a nuclear magnetic octupole moment φ much larger than expected from the nuclear shell model[1]. To explore this issue further, we are undertaking an experiment to measure the hyperfine structure in the 5D manifold of a single trapped barium-137 ion which, together with reliable calculations in alkali-like Ba^+, should resolve φ with sensitivity better than the shell model value [2]. We use a TmHo:YLF laser tuned to 2051 nm and a fiber laser tuned to 1762 nm to drive the 6S1/2 to 5D3/2 and 6S1/2 to 5D5/2 electric quadrupole transitions. These lasers allow us to selectively populate any hyperfine sub-level in the 5D manifold. We will then perform RF spectroscopy on the 5D states to make a precision measurement of the hyperfine frequency intervals. We report on the development of the laser and RF spectroscopy systems. [1] V. Gerginov, A. Derevianko, and C. E. Tanner, Phys. Rev. Lett. 91, 072501 [2] K. Beloy, A. Derevianko, V. A. Dzuba, G. T. Howell, B. B. Blinov, E. N. Fortson, arXiv:0804.4317v1 [physics.atom-ph] 28 Apr 2008

  13. Injury risk assessment of non-lethal projectile head impacts.

    PubMed

    Oukara, Amar; Nsiampa, Nestor; Robbe, Cyril; Papy, Alexandre

    2014-01-01

    Kinetic energy non-lethal projectiles are used to impart sufficient effect onto a person in order to deter uncivil or hazardous behavior with a low probability of permanent injury. Since their first use, real cases indicate that the injuries inflicted by such projectiles may be irreversible and sometimes lead to death, especially for the head impacts. Given the high velocities and the low masses involved in such impacts, the assessment approaches proposed in automotive crash tests and sports may not be appropriate. Therefore, there is a need of a specific approach to assess the lethality of these projectiles. In this framework, some recent research data referred in this article as "force wall approach" suggest the use of three lesional thresholds (unconsciousness, meningeal damages and bone damages) that depend on the intracranial pressure. Three corresponding critical impact forces are determined for a reference projectile. Based on the principle that equal rigid wall maximal impact forces will produce equal damage on the head, these limits can be determined for any other projectile. In order to validate the consistence of this innovative method, it is necessary to compare the results with other existing assessment methods. This paper proposes a comparison between the "force wall approach" and two different head models. The first one is a numerical model (Strasbourg University Finite Element Head Model-SUFEHM) from Strasbourg University; the second one is a mechanical surrogate (Ballistics Load Sensing Headform-BLSH) from Biokinetics. PMID:25400712

  14. Injury Risk Assessment of Non-Lethal Projectile Head Impacts

    PubMed Central

    Oukara, Amar; Nsiampa, Nestor; Robbe, Cyril; Papy, Alexandre

    2014-01-01

    Kinetic energy non-lethal projectiles are used to impart sufficient effect onto a person in order to deter uncivil or hazardous behavior with a low probability of permanent injury. Since their first use, real cases indicate that the injuries inflicted by such projectiles may be irreversible and sometimes lead to death, especially for the head impacts. Given the high velocities and the low masses involved in such impacts, the assessment approaches proposed in automotive crash tests and sports may not be appropriate. Therefore, there is a need of a specific approach to assess the lethality of these projectiles. In this framework, some recent research data referred in this article as “force wall approach” suggest the use of three lesional thresholds (unconsciousness, meningeal damages and bone damages) that depend on the intracranial pressure. Three corresponding critical impact forces are determined for a reference projectile. Based on the principle that equal rigid wall maximal impact forces will produce equal damage on the head, these limits can be determined for any other projectile. In order to validate the consistence of this innovative method, it is necessary to compare the results with other existing assessment methods. This paper proposes a comparison between the “force wall approach” and two different head models. The first one is a numerical model (Strasbourg University Finite Element Head Model-SUFEHM) from Strasbourg University; the second one is a mechanical surrogate (Ballistics Load Sensing Headform-BLSH) from Biokinetics. PMID:25400712

  15. Dependence of debris cloud formation on projectile shape

    NASA Astrophysics Data System (ADS)

    Konrad, C. H.; Chhabildas, L. C.; Boslough, M. B.; Piekutowski, A. J.; Poormon, K. L.; Mullin, S. A.; Littlefield, D. L.

    1994-07-01

    A two-stage lights-gas gun has been used to impact thin zinc bumpers by zinc projectiles over the velocity range of 2.4 km/s to 6.7 km/s to determine the propagation characteristics of the impact generated debris. Constant-mass projectiles in the form of spheres, discs, cylinders, and rods were used in these studies. Radiographic techniques were employed to record the debris cloud generated upon impact and the dynamic formation of the resulting rupture in an aluminum backing plate resulting from the loading of the debris cloud. The characteristics of the debris cloud generated upon impact is found to depend on the projectile shape. The data indicate that the debris front velocity is independent of the shape of the projectile, whereas the debris lateral/radial velocity is strongly dependent on projectile geometry. Spherical impactors generate the most radially dispersed debris cloud while the normal plate impactors result in column-like debris. It has been observed that the debris generated by the impact of thin plates on a thin bumper shield is considerably more damaging to a backwall than the debris generated by an equivalent-mass sphere.

  16. Dependence of debris cloud formation on projectile shape

    SciTech Connect

    Konrad, C.H.; Chhabildas, L.C.; Boslough, M.B.; Piekutowski, A.J.; Poormon, K.L.; Mullin, S.A.; Littlefield, D.L.

    1993-07-01

    A two-stage light-gas gun has been used to impact thin zinc bumpers by zinc projectiles over the velocity range of 2.4 km/s to 6.7 km/s to determine the propagation characteristics of the impact generated debris. Constant-mass projectiles in the form of spheres, discs, cylinders and rods were used in these studies. Radiographic techniques were employed to record the debris cloud generated upon impact and the dynamic formation of the resulting rupture in an aluminum backing plate resulting from the loading of the debris cloud. The characteristics of the debris cloud generated upon impact is found to depend on the projectile shape. The data indicate that the debris front velocity is independent of the shape of the projectile, whereas the debris lateral/radial velocity is strongly dependent on projectile geometry. Spherical impactors generate the most radially dispersed debris cloud while the normal plate impactors result in column-like debris. It has been observed that the debris generated by the impact of thin plates on a thin bumper shield is considerably more damaging to a backwall than the debris generated by an equivalent-mass sphere.

  17. The Chicxulub impact at the K-Pg boundary - search for traces of the projectile

    NASA Astrophysics Data System (ADS)

    Deutsch, A.

    2012-04-01

    flat REE patterns cannot originate from any known alteration process; they truly reflect a "meteoritic" component in the spherules. Accepting this fact, a certain amount of the siliceous host material (i.e., the spherules) must consist also of projectile material. Depending on the sampling site, the spherules with the flat REE distribution patterns amount to between 10 and ~70 vol% of the Chicxulub event bed. The widespread occurrence of this projectile matter in the K-Pg event bed reconciles observations with impact models [4]. Ref. [1] Trinquier A. et al. (2006) EPSL 241, 780-788. [2] Smit J. (1999) Ann. Rev. Earth Planet. Sci. 27, 75-113. [3] Schulte P. et al. (2010) Science 327, 1214-1218. [4] Artemieva N. and Morgan J. (2009) Icarus 201, 768-780.

  18. Influence of the projectiles' material in a coilgun

    NASA Astrophysics Data System (ADS)

    Hinaje, Melika; Netter, Denis

    2006-09-01

    A simple model of an electromagnetic launcher is introduced in this paper. The proposed model is an electrical one and is suitable for undergraduate students. The work consists of establishing an electrical model whose resolution gives the induced current and the speed of the projectile at a given inductor current and material projectile. In this manner by changing the material of the projectile we can deduce which one is the best. Then, a simple experiment illustrating the principles of a coilgun is described and some test results are given. Therefore, students learn electromagnetic phenomena through an electrical model which is simpler to study than a magnetic one. They have to solve a system of differential equations of the second order using numerical method. And finally, their theoretical study of the coilgun leads to an experimental bench.

  19. Perforation of HY-100 steel plates with long rod projectiles

    SciTech Connect

    Hanchak, S.J.; Altman, B.S.; Forrestal, M.J.

    1993-07-01

    The authors conducted perforation experiments with 4340 steel, rod projectiles and HY-100 steel, target plates at striking velocities between 80 and 370 m/s. Projectiles were machined to nominally 30-mm-diameter and 281-mm-length so they could be launched from a 30-mm-powder gun without sabots. The target plates were rigidly clamped at 305-mm diameter and had a nominal thickness of 10.2 mm. In addition to measuring striking and residual projectile velocities, they obtained back surface framing camera data that showed clearly the plate deformation and plug ejection process. An Imacon 792 camera provided up to 20 frames per experiment with an interframe time duration of 10 {mu}s. The modeling work is in progress, but they present a beam model that exhibits the features observed in the experiments.

  20. Using Tracker as a pedagogical tool for understanding projectile motion

    NASA Astrophysics Data System (ADS)

    Wee, Loo Kang; Chew, Charles; Hwee Goh, Giam; Tan, Samuel; Lee, Tat Leong

    2012-07-01

    This article reports on the use of Tracker as a pedagogical tool in the effective learning and teaching of projectile motion in physics. When a computer model building learning process is supported and driven by video analysis data, this free Open Source Physics tool can provide opportunities for students to engage in active enquiry-based learning. We discuss the pedagogical use of Tracker to address some common misconceptions concerning projectile motion by allowing students to test their hypothesis by juxtaposing their mental models against the analysis of real-life videos. Initial research findings suggest that allowing learners to relate abstract physics concepts to real life through coupling computer modelling with traditional video analysis could be an innovative and effective way to learn projectile motion.

  1. Projectile transverse motion and stability in electromagnetic induction launchers

    SciTech Connect

    Shokair, I.R.

    1993-12-31

    The transverse motion of a projectile in an electromagnetic induction launcher is considered. The equations of motion for translation and rotation are derived assuming a rigid projectile and a flyway restoring force per unit length that is proportional to the local displacement. Linearized transverse forces and torques due to energized coils are derived for displaced or tilted armature elements based on a first order perturbation method. The resulting equations of motion for a rigid projectile composed of multiple elements in a multi-coil launcher are analyzed as a coupled oscillator system of equations and a simple linear stability condition is derived. The equations of motion are incorporated into the 2-D Slingshot circuit code and numerical solutions for the transverse motion are obtained. For a launcher with a 10 cm bore radius with a 40 cm long solid armature, we find that stability is achieved with a restoring force (per unit length) constant of k {approx} 1 {times} 10{sup 8} N/m{sup 2}. For k = 1.5 {times} 10{sup 8} N/m{sup 2} and sample coil misalignment modeled as a sine wave of 1 mm amplitude at wavelengths of one or two meters, the projectile displacement grows to a maximum of 4 mm. This growth is due to resonance between the natural frequency of the projectile transverse motion and the coil displacement wavelength. This resonance does not persist because of the changing axial velocity. Random coil displacement is also found to cause roughly the same projectile displacement. For the maximum displacement a rough estimate of the transverse pressure is 50 bars. Results for a wound armature with uniform current density throughout show very similar displacements.

  2. Numerical simulation of fluid flow around a scramaccelerator projectile

    NASA Technical Reports Server (NTRS)

    Pepper, Darrell W.; Humphrey, Joseph W.; Sobota, Thomas H.

    1991-01-01

    Numerical simulations of the fluid motion and temperature distribution around a 'scramaccelerator' projectile are obtained for Mach numbers in the 5-10 range. A finite element method is used to solve the equations of motion for inviscid and viscous two-dimensional or axisymmetric compressible flow. The time-dependent equations are solved explicitly, using bilinear isoparametric quadrilateral elements, mass lumping, and a shock-capturing Petrov-Galerkin formulation. Computed results indicate that maintaining on-design performance for controlling and stabilizing oblique detonation waves is critically dependent on projectile shape and Mach number.

  3. Definition of lethality thresholds for KE less-lethal projectiles

    NASA Astrophysics Data System (ADS)

    Cuadros, Jaime H.

    1997-01-01

    The interest in the definition and application of the lethality threshold for KE less-lethal projectiles has increased in the last few years, as the demand for proper use of these weapons has increased from the public at large and the law enforcement community. Experiments have been performed and reported utilizing commercially available projectiles in 12 ga., 37 mm against an anthropomorphic dummy and damage criteria developed by the automobile industry. The utility of the method is discussed and future trends are presented.

  4. Projectile general motion in a vacuum and a spreadsheet simulation

    NASA Astrophysics Data System (ADS)

    Benacka, Jan

    2015-01-01

    This paper gives the solution and analysis of projectile motion in a vacuum if the launch and impact heights are not equal. Formulas for the maximum horizontal range and the corresponding angle are derived. An Excel application that simulates the motion is also presented, and the result of an experiment in which 38 secondary school students developed the application and investigated the system is given. A questionnaire survey was carried out to find out whether the students found the lessons interesting, learned new skills and wanted to model projectile motion in the air as an example of more realistic motion. The results are discussed.

  5. [The dynamics of projectile wounding. Concepts in ballistic injuries].

    PubMed

    Houdelette, P

    1998-04-01

    Analysis of the structure and terminal ballistic behavior of bullets provides a better understanding of their wounding power. The studies of ballistics specialists serve as a base. The concept of "scientific shot" remains an intellectual approach to a random phenomenon. Wound ballistic studies examine the behavior of projectiles in vivo or in a simulation medium. War events, in which projectiles do not meet requirements of international conventions, sport or hunting accidents, urban violence may confront the surgeon with various types of ballistic pathologies. The appropriate saying of Lindsey that the surgeons has to treat a wound and not a weapon should not justify etiologic ignorance. PMID:9768076

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

    PubMed

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

    2013-09-01

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

  7. Decay of quadrupole-octupole 1- states in 40Ca and 140Ce

    NASA Astrophysics Data System (ADS)

    Derya, V.; Tsoneva, N.; Aumann, T.; Bhike, M.; Endres, J.; Gooden, M.; Hennig, A.; Isaak, J.; Lenske, H.; Löher, B.; Pietralla, N.; Savran, D.; Tornow, W.; Werner, V.; Zilges, A.

    2016-03-01

    Background: Two-phonon excitations originating from the coupling of two collective one-phonon states are of great interest in nuclear structure physics. One possibility to generate low-lying E 1 excitations is the coupling of quadrupole and octupole phonons. Purpose: In this work, the γ -decay behavior of candidates for the (21+⊗31-)1- state in the doubly magic nucleus 40Ca and in the heavier and semimagic nucleus 140Ce is investigated. Methods: (γ ⃗,γ') experiments have been carried out at the High Intensity γ -ray Source (HI γ S ) facility in combination with the high-efficiency γ -ray spectroscopy setup γ3 consisting of HPGe and LaBr3 detectors. The setup enables the acquisition of γ -γ coincidence data and, hence, the detection of direct decay paths. Results: In addition to the known ground-state decays, for 40Ca the decay into the 31- state was observed, while for 140Ce the direct decays into the 21+ and the 02+ state were detected. The experimentally deduced transition strengths and excitation energies are compared to theoretical calculations in the framework of EDF theory plus QPM approach and systematically analyzed for N =82 isotones. In addition, negative parities for two J =1 states in 44Ca were deduced simultaneously. Conclusions: The experimental findings together with the theoretical calculations support the two-phonon character of the 11- excitation in the light-to-medium-mass nucleus 40Ca as well as in the stable even-even N =82 nuclei.

  8. MEMIN: Chemical Modification of Projectile Spheres, Target Melts and Shocked Quartz in Hypervelocity Impact Experiments

    NASA Astrophysics Data System (ADS)

    Ebert, M.; Hecht, L.; Deutsch, A.; Kenkmann, T.

    2011-03-01

    We present results of hypervelocity cratering experiments using iron meteorite as projectile and a sandstone target. The ejecta show shock features (melting, PDFs, lechatelierite) and physical as well as chemical mixing between projectile and target.

  9. Cosmic flows on 100 h-1 Mpc scales: standardized minimum variance bulk flow, shear and octupole moments

    NASA Astrophysics Data System (ADS)

    Feldman, Hume A.; Watkins, Richard; Hudson, Michael J.

    2010-10-01

    The low-order moments, such as the bulk flow and shear, of the large-scale peculiar velocity field are sensitive probes of the matter density fluctuations on very large scales. In practice, however, peculiar velocity surveys are usually sparse and noisy, which can lead to the aliasing of small-scale power into what is meant to be a probe of the largest scales. Previously, we developed an optimal `minimum variance' (MV) weighting scheme, designed to overcome this problem by minimizing the difference between the measured bulk flow (BF) and that which would be measured by an ideal survey. Here we extend this MV analysis to include the shear and octupole moments, which are designed to have almost no correlations between them so that they are virtually orthogonal. We apply this MV analysis to a compilation of all major peculiar velocity surveys, consisting of 4536 measurements. Our estimate of the BF on scales of ~100h-1Mpc has a magnitude of |v| = 416 +/- 78 kms -1 towards Galactic l = 282° +/- 11° and b = 6° +/- 6°. This result is in disagreement with Λ cold dark matter with Wilkinson Microwave Anisotropy Probe 5 (WMAP5) cosmological parameters at a high confidence level, but is in good agreement with our previous MV result without an orthogonality constraint, showing that the shear and octupole moments did not contaminate the previous BF measurement. The shear and octupole moments are consistent with WMAP5 power spectrum, although the measurement noise is larger for these moments than for the BF. The relatively low shear moments suggest that the sources responsible for the BF are at large distances.

  10. High performance projectile seal development for non perfect railgun bores

    SciTech Connect

    Wolfe, T.R.; Vine, F.E. Le; Riedy, P.E.; Panlasigui, A.; Hawke, R.S.; Susoeff, A.R.

    1997-01-01

    The sealing of high pressure gas behind an accelerating projectile has been developed over centuries of use in conventional guns and cannons. The principal concern was propulsion efficiency and trajectory accuracy and repeatability. The development of guns for use as high pressure equation-of-state (EOS) research tools, increased the importance of better seals to prevent gas leakage from interfering with the experimental targets. The development of plasma driven railguns has further increased the need for higher quality seals to prevent gas and plasma blow-by. This paper summarizes more than a decade of effort to meet these increased requirements. In small bore railguns, the first improvement was prompted by the need to contain the propulsive plasma behind the projectile to avoid the initiation of current conducting paths in front of the projectile. The second major requirements arose from the development of a railgun to serve as an EOS tool where it was necessary to maintain an evacuated region in front of the projectile throughout the acceleration process. More recently, the techniques developed for the small bore guns have been applied to large bore railguns and electro-thermal chemical guns in order to maximize their propulsion efficiency. Furthermore, large bore railguns are often less rigid and less straight than conventional homogeneous material guns. Hence, techniques to maintain seals in non perfect, non homogeneous material launchers have been developed and are included in this paper.

  11. Projectile deformation effects in the breakup of 37Mg

    NASA Astrophysics Data System (ADS)

    Shubhchintak; Chatterjee, R.; Shyam, R.

    2016-05-01

    We study the breakup of 37Mg on Pb at 244MeV/u with the recently developed extended theory of Coulomb breakup within the postform finite range distorted wave Born approximation that includes deformation of the projectile. Comparing our calculated cross section with the available Coulomb breakup data we determine the possible ground state configuration of 37Mg.

  12. On the Trajectories of Projectiles Depicted in Early Ballistic Woodcuts

    ERIC Educational Resources Information Center

    Stewart, Sean M.

    2012-01-01

    Motivated by quaint woodcut depictions often found in many late 16th and 17th century ballistic manuals of cannonballs fired in air, a comparison of their shapes with those calculated for the classic case of a projectile moving in a linear resisting medium is made. In considering the asymmetrical nature of such trajectories, the initial launch…

  13. Projectile Motion in the "Language" of Orbital Motion

    ERIC Educational Resources Information Center

    Zurcher, Ulrich

    2011-01-01

    We consider the orbit of projectiles launched with arbitrary speeds from the Earth's surface. This is a generalization of Newton's discussion about the transition from parabolic to circular orbits, when the launch speed approaches the value [image omitted]. We find the range for arbitrary launch speeds and angles, and calculate the eccentricity of…

  14. The Long Decay Model of One-Dimensional Projectile Motion

    ERIC Educational Resources Information Center

    Lattery, Mark Joseph

    2008-01-01

    This article introduces a research study on student model formation and development in introductory mechanics. As a point of entry, I present a detailed analysis of the Long Decay Model of one-dimensional projectile motion. This model has been articulated by Galileo ("in De Motu") and by contemporary students. Implications for instruction are…

  15. Projectile General Motion in a Vacuum and a Spreadsheet Simulation

    ERIC Educational Resources Information Center

    Benacka, Jan

    2015-01-01

    This paper gives the solution and analysis of projectile motion in a vacuum if the launch and impact heights are not equal. Formulas for the maximum horizontal range and the corresponding angle are derived. An Excel application that simulates the motion is also presented, and the result of an experiment in which 38 secondary school students…

  16. Using Tracker as a Pedagogical Tool for Understanding Projectile Motion

    ERIC Educational Resources Information Center

    Wee, Loo Kang; Chew, Charles; Goh, Giam Hwee; Tan, Samuel; Lee, Tat Leong

    2012-01-01

    This article reports on the use of Tracker as a pedagogical tool in the effective learning and teaching of projectile motion in physics. When a computer model building learning process is supported and driven by video analysis data, this free Open Source Physics tool can provide opportunities for students to engage in active enquiry-based…

  17. Fusion of a polarized projectile with a polarized target

    SciTech Connect

    Christley, J.A.; Johnson, R.C.; Thompson, I.J.

    1995-07-15

    The fusion cross sections for a polarized target with both unpolarized and polarized projectiles are studied. Expressions for the observables are given for the case when both nuclei are polarized. Calculations for fusion of an aligned {sup 165}Ho target with {sup 16}O and polarized {sup 7}Li beams are presented.

  18. 73. DETAIL OF 'A' FRAME STRUCTURE LOOKING NORTH SHOWING PROJECTILE ...

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

    73. DETAIL OF 'A' FRAME STRUCTURE LOOKING NORTH SHOWING PROJECTILE CAR, CAMERA TOWER, CANTILEVERED WALKWAYS AND ELECTRICAL GEAR, August 17, 1948. (Original photograph in possession of Dave Willis, San Diego, California.) - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  19. 22. VAL, VIEW OF PROJECTILE LOADING DECK LOOKING NORTHEAST TOWARD ...

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

    22. VAL, VIEW OF PROJECTILE LOADING DECK LOOKING NORTHEAST TOWARD TOP OF CONCRETE 'A' FRAME STRUCTURE SHOWING DRIVE CABLES, DRIVE GEAR, BOTTOM OF CAMERA TOWER AND 'CROWS NEST' CONTROL ROOM. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  20. 78. PHOTO OF A PROJECTILE FIRING USING A SABOT TAKEN ...

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

    78. PHOTO OF A PROJECTILE FIRING USING A SABOT TAKEN WITH A 70 MM MITCHEL MOTION PICTURE CAMERA, Date unknown, circa 1950. (Original photograph in possession of Dave Willis, San Diego, California.) Photograph represents central frame of negative. - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

  1. Apparatus for Teaching Physics: A Versatile Projectile Motion Board.

    ERIC Educational Resources Information Center

    Prigo, Robert B.; Korda, Anthony

    1984-01-01

    Describes the design and use of a projectile motion apparatus to illustrate a variety of projective motion results typically discussed in an introductory course. They include independence of horizontal (constant speed) and vertical (constant acceleration) motions, parabolic path shape, and other types of motion. (JN)

  2. Survivability of Meteorite Projectiles - Results from Impact Experiments

    NASA Technical Reports Server (NTRS)

    Bland, P. A.; Cintala, M. J.; Hoerz, F.; Cressey, G.

    2001-01-01

    An experimental impact study investigating the fragmentation of various projectiles, including meteorite, at speeds up to 1.8 km/s. The results have implications for the survivability of meteorites impacting planetary and asteroidal surfaces. Additional information is contained in the original extended abstract.

  3. 34. mu. s isomer at high spin in sup 212 Fr: Evidence for a many-particle octupole coupled state

    SciTech Connect

    Byrne, A.P.; Dracoulis, G.D.; Schiffer, K.J.; Davidson, P.M.; Kibedi, T.; Fabricius, B.; Baxter, A.M.; Stuchbery, A.E. Australian National University, G.P.O. Box 4, Canberra, Australian Capital Territory )

    1990-07-01

    A very high spin isomeric state with {tau}{sub {ital m}}=34(3) {mu}s has been observed at an excitation energy of 8.5 MeV in {sup 212}Fr. The experimental evidence favors an {ital E}3 assignment, with a very large {ital E}3 transition strength, {ital B}({ital E}3)=100(12){times}10{sup 3} {ital e}{sup 2}fm{sup 6}, to one of the {gamma} rays de-exciting the isomer. The observed properties are in very good agreement with the characteristics of a 34{sup +} state predicted by the multiparticle octupole vibration model.

  4. Interference between selected dipoles and octupoles in the optical second-harmonic generation from spherical gold nanoparticles.

    PubMed

    Butet, J; Bachelier, G; Russier-Antoine, I; Jonin, C; Benichou, E; Brevet, P-F

    2010-08-13

    Optical second-harmonic generation from gold nanoparticles is investigated both experimentally and theoretically. The contribution of octupoles is reported for the first time in the second-harmonic emission pattern, by using an harmonic polarization in the scattering plane. The experimental results presented here for particle sizes up to 100 nm are in excellent agreement with finite element method simulations involving the normal surface term only in the nonlinear polarization source. In addition, analytical calculations based on nonlinear Mie scattering theory clearly evidence the constructive and destructive interferences occurring between the dipolar and octupolar responses selected with this polarization configuration. PMID:20868074

  5. Reflection Asymmetric Shapes in the Neutron-Rich 140,143Ba Isotopes

    NASA Astrophysics Data System (ADS)

    Zhu Sheng-jiang (S, J. Zhu; Wang, Mu-ge; J, H. Hamilton; A, V. Ramayya; B, R. S. Babu; W, C. Ma; Long, Gui-lu; Deng, Jing-kang; Zhu, Ling-yan; Li, Ming; T, N. Ginter; J, Komicki; J, D. Cole; R, Aryaeinejad; Y, K. Dardenne; M, W. Drigert; J, O. Rasmussen; Ts, Yu Oganessian; M, A. Stoyer; S, Y. Chu; K, E. Gregorich; M, F. Mohar; S, G. Prussin; I, Y. Lee; N, R. Johnson; F, K. McGowan

    1997-08-01

    Level schemes for the neutron-rich 140,143Ba nuclei have been determined by study of prompt γ-rays in spontaneous fission of 252Cf. The level pattern and enhanced E1 transitions between π = + and π = - bands show reflection asymmetric shapes with simplex quantum number s = +1 in 140Ba and s = ±i in 143Ba, respectively. The octupole deformation stability with spin variation has been discussed.

  6. Evaluation of different projectiles in matched experimental eye impact simulations.

    PubMed

    Weaver, Ashley A; Kennedy, Eric A; Duma, Stefan M; Stitzel, Joel D

    2011-03-01

    Eye trauma results in 30,000 cases of blindness each year in the United States and is the second leading cause of monocular visual impairment. Eye injury is caused by a wide variety of projectile impacts and loading scenarios with common sources of trauma being motor vehicle crashes, military operations, and sporting impacts. For the current study, 79 experimental eye impact tests in literature were computationally modeled to analyze global and localized responses of the eye to a variety of blunt projectile impacts. Simulations were run with eight different projectiles (airsoft pellets, baseball, air gun pellets commonly known as BBs, blunt impactor, paintball, aluminum, foam, and plastic rods) to characterize effects of the projectile size, mass, geometry, material properties, and velocity on eye response. This study presents a matched comparison of experimental test results and computational model outputs including stress, energy, and pressure used to evaluate risk of eye injury. In general, the computational results agreed with the experimental results. A receiver operating characteristic curve analysis was used to establish the stress and pressure thresholds that best discriminated for globe rupture in the matched experimental tests. Globe rupture is predicted by the computational simulations when the corneoscleral stress exceeds 17.21 MPa or the vitreous pressure exceeds 1.01 MPa. Peak stresses were located at the apex of the cornea, the limbus, or the equator depending on the type of projectile impacting the eye. A multivariate correlation analysis revealed that area-normalized kinetic energy was the best single predictor of peak stress and pressure. Additional incorporation of a relative size parameter that relates the projectile area to the area of the eye reduced stress response variability and may be of importance in eye injury prediction. The modeling efforts shed light on the injury response of the eye when subjected to a variety of blunt projectile

  7. Parity splitting and E1/E2 branching in the alternating parity band of {sup 240}Pu from two-center octupole wave functions using supersymmetric quantum mechanics

    SciTech Connect

    Jolos, R. V.; Brentano, P. von

    2011-08-15

    An interpretation is suggested of the recently published experimental data on the alternating parity bands in {sup 240}Pu. The interpretation is based on the assumption that the main role in the description of the properties of the alternating parity bands plays the octupole mode which preserves the axial symmetry. The mathematical technique of the supersymmetric quantum mechanics is used for the realization of the model with the two-center octupole wave functions. A good description of the parity splitting and of the ratio of the dipole and quadrupole transitional moments is obtained for the first two bands.

  8. A comparison of finite element analysis to smooth particle hydrodynamics for application to projectile impact on cementitious material

    NASA Astrophysics Data System (ADS)

    Nordendale, Nikolas A.; Heard, William F.; Sherburn, Jesse A.; Basu, Prodyot K.

    2016-03-01

    The response of structural components of high-strength cementitious (HSC) materials to projectile impact is characterized by high-rate fragmentation resulting from strong compressive shock waves coupled with reflected tensile waves. Accurate modeling of armor panels of such brittle materials under high-velocity projectile impact is a complex problem requiring meticulous experimental characterization of material properties. In a recent paper by the authors, an approach to handle such problems based on a modified Advanced Fundamental Concrete (AFC) constitutive model was developed. In the HSC panels considered in this study, an analogous approach is applied, and the predictions are verified with ballistic impact test data. Traditional Lagrangian finite element analysis (FEA) of these problems tends to introduce errors and suffers from convergence issues resulting from large deformations at free surfaces. Also, FEA cannot properly account for the issues of secondary impact of spalled fragments when multiple armor panels are used. Smoothed particle hydrodynamics (SPH) is considered to be an attractive alternative to resolve these and other issues. However, SPH-based quantitative results have been found to be less accurate than the FEA-based ones when the deformations are not sufficiently large. This paper primarily focuses on a comparison of FEA and SPH models to predict high-velocity projectile impact on single and stacked HSC panels. Results are compared to recent ballistic experiments performed as a part of this research, and conclusions are drawn based on the findings.

  9. Reflecting Reflective Practice

    ERIC Educational Resources Information Center

    Galea, Simone

    2012-01-01

    This paper demystifies reflective practice on teaching by focusing on the idea of reflection itself and how it has been conceived by two philosophers, Plato and Irigaray. It argues that reflective practice has become a standardized method of defining the teacher in teacher education and teacher accreditation systems. It explores how practices of…

  10. The FRS Ion Catcher - A facility for high-precision experiments with stopped projectile and fission fragments

    NASA Astrophysics Data System (ADS)

    Plaß, W. R.; Dickel, T.; Purushothaman, S.; Dendooven, P.; Geissel, H.; Ebert, J.; Haettner, E.; Jesch, C.; Ranjan, M.; Reiter, M. P.; Weick, H.; Amjad, F.; Ayet, S.; Diwisch, M.; Estrade, A.; Farinon, F.; Greiner, F.; Kalantar-Nayestanaki, N.; Knöbel, R.; Kurcewicz, J.; Lang, J.; Moore, I.; Mukha, I.; Nociforo, C.; Petrick, M.; Pfützner, M.; Pietri, S.; Prochazka, A.; Rink, A.-K.; Rinta-Antila, S.; Schäfer, D.; Scheidenberger, C.; Takechi, M.; Tanaka, Y. K.; Winfield, J. S.; Yavor, M. I.

    2013-12-01

    At the FRS Ion Catcher at GSI, projectile and fission fragments are produced at relativistic energies, separated in-flight, range-focused, slowed down and thermalized in a cryogenic stopping cell. A multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) is used to perform direct mass measurements and to provide an isobarically clean beam for further experiments, such as mass-selected decay spectroscopy. A versatile RF quadrupole transport and diagnostics unit guides the ions from the stopping cell to the MR-TOF-MS, provides differential pumping, ion identification and includes reference ion sources. The FRS Ion Catcher serves as a test facility for the Low-Energy Branch of the Super-FRS at the Facility for Antiproton and Ion Research (FAIR), where the cryogenic stopping cell and the MR-TOF-MS will be key devices for the research with stopped projectile and fission fragments that will be performed with the experiments MATS and LaSpec. Off-line tests of the stopping cell yield a combined ion survival and extraction efficiency for 219Rn ions of about 30% and an extraction time of about 25 ms. The stopping cell and the MR-TOF-MS were commissioned on-line as part of the FRS Ion Catcher. For the first time, a stopping cell for exotic nuclei was operated on-line at cryogenic temperatures. Using a gas density almost two times higher than ever reached before for a stopping cell with RF ion repelling structures, various 238U projectile fragments were thermalized and extracted with very high efficiency. Direct mass measurements of projectile fragments were performed with the MR-TOF-MS, among them the nuclide 213Rn with a half-life of 19.5 ms only.